ImagineNano Abstract Booklet (part II)

Oral Development of Hydrogel membranes for long term biopotential monitoringusingflexible wet electrodes

Carme de Haro1 2 R.Ruiz 1 P. Lacharmoise and 1 N. Guilera

cdeharo@cetemmsa.com 1 2

Fundació CETEMMSA, Avd. Ernest Lluch, 36 08302 Mataró (Barcelona) RGB Medical Devices S.A.,Alfonso Gómez 42 28037 Madrid - Spain

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Ubiquitous monitoring of biopotentials can greatly enhance comfort, health and safety of patients dealing with chronic diseases. For home use, clinical grade adhesive electrodes are often cited as irritating and uncomfortable, leading to low usage compliance [1]. For long-term monitoring it is mandatory to have innocuous and disposable electrodes with constant impedance over long periods of time.

In previous work we developed 100% dry electrodes to fabricate a T-shirt for long-term ECG monitoring [2]. These dry electrodes exhibit low stability: they change their impedance over length of use and may even vary within a single ECG register. We concluded that dry electrodes can´t bring enough stability and thus electrodes with interfacial wet membranes are preferred. In the current work we present the development, fabrication and characterization of wet bioelectrodes for long-term biopotential monitoring. The new printed and textile-based electrodes allow carrying out long-term recordings due to their biocompatibility (non-toxic, nonallergic and non-irritant). However, they present high electrode-tissue interface impedance, providing a low level signal with clear motion artifacts that can´t be digitally filtered without losing valuable information. To improve the signal quality, a non-irritating hydrogel membrane which improves the contact impedance and reduces the movement artifact is being developed. Apart from biocompatibility, the developed membranes must satisfy two basic requirements: good mechanical adhesion to the skin of the patient and interfacial impedance equal or lower than conventional ECG electrodes. We are studying two different hydrogel formulations based on acrylamide polymers on one hand and polyvinylpyrrolidone (NVP) on the

other hand. Apart from the hydrogel formulation, we focused our attention in the mechanical behavior of the membranes. In order to improve their mechanical stability we propose the use of embedded tissue that strengthens the hydrogel membrane without losing flexibility. A wide variety of tissues were tested, being XXX and XXX the ones that showed best compatibility into the membrane. Pictures of tissue embedded membranes are shown in Figure 1. Relative impedance measurements between commercial ECG electrodes and textile electrodes with different formulations of interfacial membranes are shown in Figure 2. The impedance of the textile electrodes remain below the measured impedance for commercial ECG electrodes independently of the NVP formulation membrane.

We have proved that hydrogel-based interfacial membranes can be used in combination with textile electrodes for long term ECG monitoring.

The developed solution provides good functional behavior in terms of stability, mechanical adhesion and conductivity. These membranes are actually being tested in T-shirt prototypes with integrated textile sensors which are expected to allow for comfortable ubiquitous ECG monitoring. The final product is a T-shirt where the electrodes will do the register in continuous. The T-shirt has 4 different register points, two on the front of the Tshirt and the others two on the back. In Figure 3 we present one prototype of the T-shirt with textile ECG electrodes.

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References [1] A. Gruetzmann, S. Hansen, J. M端ller. Novel dry electrodes for ECG monitoring. Physiol. Meas.

28 (2007) 1375-1390.

[2] C. de Haro, C. Carenas, R.Ruiz, E. Calderon, L. Francesch. Development of new printed electrodes for biopotential monitoring.

Tarragona 25-27 May 2012, 8th International Conference on Organic Electronics -ICOE 2012.

Oral.

[3] L. Beckmann, C. Neuhaus et al.

Characterization of textile electrodes and conductors using standardized measurement setups. Physiol. Meas. 31 (2010) 233-247.

Figure 1: a) hydrogel membrane with synthetic wadding. b) hydrogel membrane with web cotton c) hydrogel membrane with silk.

Figure 2: Impedance register of different ECG electrodes, referenced to ECG commercials.

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Figure 3: View of different parts of developed T-shirt to biopotencials registers.

Invited Force nanoscopy of microbial pathogens

Yves DufrĂŞne

Yves.Dufrene@uclouvain.be Institute of Life Sciences, UniversitĂŠ catholique de Louvain, Belgium

Progress in nanomedicine relies on the development of advanced tools for imaging and manipulating biological systems on the nanoscale. Among these, atomic force microscopy (AFM) techniques have emerged as a powerful platform for analyzing the structure, properties and functions of living cells, including microbial pathogens. AFM imaging enables researchers to observe microbial cell walls in solution and at high resolution, and to monitor their remodelling upon interaction with drugs. In addition, single-molecule force spectroscopy analyzes the localization, mechanics and interactions of the individual cell wall constituents, thereby contributing to our understanding of how cell surface receptors are spatially-organized (e.g. clustering) and respond to force (e.g. single specific bonds, sequential unfolding of single protein domains, zipper-like adhesion, and spring-like properties).

Knowledge of these molecular properties is critical to our understanding of pathogen surface interactions. In the future, we expect this new form of nanoscopy to have an important impact on nanomedicine, particularly for understanding microbe-drug and microbe-host interactions and for developing new antimicrobial strategies. I will survey recent breakthroughs we have made in applying AFM to microbial pathogens [1-4].

References

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[1] Beaussart et al. (2012). ACS Nano 12: 1095010964.

[2] El-Kirat-Chatel et al. (2012). ACS Nano 12: 10792-10799.

[3] Alsteens et al. (2012). ACS Nano, 6: 77037711.

[4] Tripathi et al. (2013). ACS Nano, 10.1021/nn400705u.

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Oral Metallophilic Hydrogels: A New Family of Injectable and Self-Healing Materials

Damien Dupin P. Casuso, N. Diaz I. Odroziola, H. - J. Grande G. Cabañero and I. Loinaz

IK4-CIDETEC, Parque Tecnológico de San Sebastián, Paseo Miramón 196, 20009 Donostia-San Sebastián, Spain

ddupin@cidetec.es

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properties for a wide range of application from tissue engineering as injectable scaffolds, synovial liquid replacement due its shear-thickening behavior to material for wound healing.

[1] Burkoth, A. K. et al. BIOMATERIALS 21 (2000) 2395-2404.

[2] Klouda, L. et al. EUR. J. PHARM. BIOPHARM. 68 (2008) 34-45.

[3] Casuso, P. et al. ORG. BIOMOL. CHEM. 8 (2010) 5455-5458.

[4] Odriozola, I. et al. ORG. BIOMOL. CHEM. 9 (2011) 5059-5061.

[5] Patent number EP11382365.

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References

Figure 1: Self-healing behavior of the supramolecular hydrogel.

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In-situ forming hydrogel systems have attracted considerable interest as injectable scaffolds for tissue engineering and drug delivery due to their easy applications and minimally invasive injection procedure. [1,2] Our research group has recently developed a new generation of injectable supramolecular hydrogels based on low molecularweight Au (I) and Ag (I) thiolates. [3,4] Here we present a new family of polymeric hydrogel with self-healing properties and adjustable mechanical properties. [5] Supramolecular polymeric hydrogels were obtained by mixing an aqueous solution of salt metals (AgNO3 or HAuCl4) with an aqueous solution of thiolated polymer at physiological pH. The instantaneous gel formation allows its application as injectable scaffold for tissue engineering, e.g. bone or cartilage replacement.

Interestingly the supramolecular polymeric hydrogel exhibits self-healing properties (Figure 1) due to the reversible supramolecular interaction of thiolates metal (I).

Moreover, the mechanical properties of these supramolecular hydrogels could be tuned on demand by varying the amount of metal ions incorporated into the hydrogel. For example, hydrogels with high amount of added gold exhibit a shear-thickening behavior similar to synovial liquid (Figure 2). Furthermore supramolecular hydrogels with lower gold concentration show more toughness but their self-healing properties are kept in (Figure 3). Also a judicious selection of the metal allows the hydrogel to be an excellent cell proliferation scaffold or to have antibacterial properties when gold and silver are used, respectively.

In summary, this new family of polymeric supramolecular hydrogels offers advantageous

Figure 2: Variation of G’ (solid behavior) and G’’ (liquid behavior) with frequency.

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Figure 3: Variation of the storage modulus (G’) with different amount of metallophilic interactions ranging from 20 to 110 mol % based on the initial quantity of thiols.

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Oral Nanoassembly of the Protein Corona on Nanoparticles

Giancarlo Franzese 1 P. Vilaseca 1 O. Vilanova M. Bernabei1 2 K. A. Dawson

1

1

Cellular responses to materials in a biological medium reflect greatly the adsorbed biomolecular layer, rather than the material itself. Here, we study by molecular dynamic simulations the competitive protein adsorption on surfaces, i.e. the non-monotonic behavior of the amount of protein adsorbed on a surface in contact with plasma as a function of contact time and plasma concentration. We study the effects of different curvatures and nanoparticles size when the surface chemistry is the same [1].

References [1] P. Vilaseca, K. A. Dawson, and G. Franzese, “Understanding and modulating the competitive surface-adsorption of proteins�, arXiv: 1202.3796 (2012).

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gfranzese@ub.edu

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Departament de Fisica Fonamental, Facultat de Fisica, Universitat de Barcelona, Diagonal 645, 08028, Barcelona, Spain, 2 Center for BioNano Interactions (CBNI), University College of Dublin, Ireland

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Figure 1: Simulation snapshot of a model plasma solution in contact with a nanoparticle (in the center). The model plasma is made of three different proteins (Albumin, Immunoglobulin-gamma, Fibrinogen) adsorbing on a hydrophobic nanoparticle and selfassempling in a protein soft corona.

Invited Challenges in spintronic platforms for biomedical applications 1

INESC-MN–Ins. de Engenharia de Sistemas e Computadores-Microsistemas e Nanotecnologias and IN-Ins. of Nanoscience and Nanotechnology, Rua Alves Redol, 9, 1000-029, Lisbon, Portugal; 2 INL–Int. Iberian Nanotechnology Laboratory, Av. Mestre José Veiga, 4715-31 Braga, Portugal 3 IBB-Ins. for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho Campus de Gualtar, 4700-057 Braga, Portugal 4 IBB- Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering (CEBQ), Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal 5 INESC-ID–Ins. de Engenharia de Sistemas e Computadores-Inovação e Desenvolvimento, Rua Alves Redol, 9, 1000-029, Lisbon, Portugal 6 Laboratory of Neurosciences, Faculty of Medicine, University of Lisbon, Portugal 7 ICVS, U.Minho, Braga, Portugal

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Integrated spintronic biochip platforms are being developed for portable, point-of-care, diagnostic and cytometric applications [1,2]. Hybrid systems incorporating magnetoresistive sensors are applied to neuroelectronic studies and biomedical imaging, namely magnetoencephalography and magnetocardiography. Lab-on-a-chip MR-based platforms are under development to perform biological studies at the single molecule level. This review introduces and discusses the potential and main characteristics of those MR-based biomedical devices, comparing to the existing technologies, while giving particular examples of targeted applications. Applications to the detection of DNA hybridization events (DNA-chips) [3] and antibodyantigen recognition at immunoassays (immunochips) [4] are discussed. Particular examples for cell free DNA and genomic sequences detection, for pathogen (Salmonella enteritidis, see Fig.1) detection and for flow cytometry (separation and counting) of CD34+ magnetically labeled cells coming from bone marrow or cord blood samples are given. Moreover, lateral immuno-assay configurations where analytes are labeled with magnetic nanoparticles are discussed. For biomedical imaging applications, field sensitivity is being pushed towards 1pT/sqrt(Hz) and below in hybrid devices incorporating flux guides with the magnetoresistive element allowing the direct detection of bio-magnetic fields (from brain and heart). For neuroelectronic applications, sensors are being incorporated in microelectrode arrays (Si and polyimide) to record spontaneous or stimulated neural activity (in vitro and in vivo, see Fig.2).

Paulo P. Freitas

1,2

F.A. Cardoso1, V.C. Martins2 E. Fernandes2,3, S.A.M. Martins4 T. Dias1,4, J.P. Amaral1 S. Cardoso1, J. Germano5 T. Costa5, M.S. Piedade5 J. Gaspar2, J. Noh2 M. Costa2, H. Fonseca2 M. Debs2, R. Ferreira2 A.M. Sebastião6 and V. Pinto7

paulo.freitas@inl.int

References [1] P. P. Freitas, F. A. Cardoso, V. C. Martins, S. A. M. Martins, J. Loureiro, J. Amaral, R. C. Chaves, S.Cardoso, L. P. Fonseca, A. M. Sebastião, M. Pannetier-Lecoeur and C. Fermon “Spintronic platforms for biomedical applications”, Lab Chip, 12, 546-557 (2012).

[2] V.C. Martins, J. Germano, F.A. Cardoso, J. Loureiro, S. Cardoso, L. Sousa, M. Piedade, L.P. Fonseca, P.P. Freitas “Challenges and trends in the development of a magnetoresistive biochip portable platform” Journal of Magnetism and Magnetic Materials, 322, 1655-1663 (2010).

[3] V.C. Martins, F.A. Cardoso, J. Germano, S. Cardoso, L. Sousa, M. Piedade, P.P. Freitas, L.P. Fonseca “Femtomolar Limit of Detection with a Magnetoresistive Biochip” Biosensors and Bioelectronics, 24, 2690-2695 (2009).

[4] Sofia A. M. Martins, Verónica C. Martins, Filipe A. Cardoso, Paulo P. Freitas, Luís P. Fonseca, “Waterborne Pathogen Detection Using a Magnetoresistive Immuno-Chip”, in Molecular Biological Technologies for Ocean Sensing (Sonia Tiquia, ed.), Springer Protocols Handbooks series, Humana Press, 263-288 (2012).

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Figure 2: (a) SEM image of the probe shafts with MR sensors, (b) transfer curve of a used MTJ sensors and its structure. (c) MR needles array with respect to the different hippocampus structures and (d) sensor output after an impulse in the CA1 brain region..

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Figure 1: Phage-based magnetoresitive biochip measurements performed on an electronic reader. (a) Measurement curves for different sensors (Reference sensor – no probe; Positive sensor – specific phage for Salmonella; Negative sensor – phage for Campylobacter) on the same chip for a Salmonella sample analysis. (b) Picture from the biochip over a culture plate with grown Salmonella colonies. (c) SEM picture from a gold surface with immobilize bacteriophage recognizing Salmonella cells.

Oral Application of the enzymatic product mediated stabilization of in situ produced CdS quantum dots: serum paraoxonase, acetylcholine esterase and glutathion reductase detection

Gaizka Garai-Ibabe L. Saa and V. Pavlov

ggarai@cicbiomagune.es

CICbiomaGUNE, Parque Tecnologico de San Sebastian, Paseo Miramón 182, 20009, Donostia, Spain

Detection of analytes in biosensing is carried out by interaction of biological recognition elements (DNA, enzymes, antibodies and so on) with analytes of interest. The event of recognition is transduced and amplified to yield a signal measurable by physical techniques such as UV-Vis and fluorescence spectroscopy, Raman spectroscopy, electrochemistry etc.

Semiconductor inorganic fluorescent nanoparticles, known as quantum dots (QDs), have been extensively used in recent years as labels for antibodies, DNA and small molecules in bioanalytical affinity assays and imaging.[1,2,3]The advantages of QDs over traditional organic fluorophores include higher quantum yield, reduced photo-bleaching and higher extinction coefficient. Until now QDs based assays relied on pre-synthesized semiconductor NPs. However, the drawbacks of such assays used to be the high background signals caused by the nonspecific adsorption of decorated QDs on surfaces or poor quenching of donor couples. Thus we believed that the generation of QDs in situ can address these drawbacks of relevant analytical systems by decreasing the background signal.

Here we introduce a novel concept in bioanalysis and apply it to the rapid, highly sensitive and inexpensive fluorimetric detection of different enzymes with biomedical interest: serum paraoxonase-1(PON-1)(Figure 1), acetylcholine esterase (AChE) (Figure 2) and glutathione reductase (GR)(Figure 3 3).[4,5,6].

[2] Goldman, E. R.; Clapp, A. R.; Anderson, G. P.; Uyeda, H. T.; Mauro, J. M.; Medintz, I. L.; Mattoussi, H. Anal. Chem., 76 (2004) 684.

[3] Green, M. Angew. Chem. Int. Ed., 43 (2004) 4129.

[4] Garai-Ibabe G., Möller M., Pavlov V. Anal.

Chem., 84 (2012) 8033.

[5] Garai-Ibabe G., Saa L., Pavlov V. submitted Analytical Chemistry.

[6] Garai-Ibabe G., Saa L., Pavlov V. submitted Analytical Chemistry

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Figure 1 A) Detection of PON1 activity by the enzymatic modulation of growth of fluorescent CdS QDs. B) Emission spectra of CdS QDs formed in the system containing PTA (2mM), Na2S (0.3 mM), Na3PO3S (0.9 mM), Cd(NO3)2 (1.25 mM) and various concentrations of rHuPON1: a) 0 mU mL-1; b) 0.625 mU mL-1; c) 1.25 mU mL-1; d) 2.5 mU mL-1; e) 5 mU mL-1; f) 10 mU mL-1; g) 20 mU mL-1; h) 40 mU mL-1. C) Calibration curve of rHuPON1, measured by the enzymatic modulation of growth of fluorescent CdS QDs, □, and the standard PA method, ■.

References

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[1] Zhang, Y.; So, M.-K.; Loening, A. M.; Yao, H.; Gambhir, S. S.; Rao, J. Angew. Chem. Int. Ed., 45 (2006) 4936.

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Figure 3 A) Detection of GR activity by the enzymatic stabilization of fluorescent CdS B) Emission spectra of CdS QDs formed in diluted human serum (1:1000) containing NADPH (17.5 碌M), Na2S (0.1 mM), Cd(NO3)2 (1.25 mM) and different concentrations of GR: a) 0 pM; b) 5 pM; c) 10 pM; d) 25 pM; e) 50 pM;. C) Calibration curve of GR at 位=550 nm.

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Figure 2 A) Detection of AChE activity by the enzymatic productmediated stabilization of fluorescent CdS QDs B) Fluorescence intensities of the formed CdS QDs in the system containing different concentrations of added standard solution of AChE, ATCh (0.5 mM), Na2S (0.1 mM), Cd(NO3)2 (1.25 mM) and varying volumes of human serum a) 5 nL; b) 6.7 nL; c) 10 nL; d)13.3 nL. C) Dependence of the calculated AChE activity on serum volume.

Oral Detection of Alzheimer Disease Markers by High Performance Plasmonic Silver Nanostars

Jose V. Garcia-Ramos A. Garcia-Leis and S. Sanchez-Cortes

jvicente.g.ramos@csic.es Instituto de Estructura de la Materia. IEM-CSIC. Serrano, 121. 28006 Madrid. Spain

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The manufacture of nanoparticles (NPs) with metallic plasmonic properties, displaying advanced spectroscopic applications is one of the tasks of our research Group. In fact, shape control of metal nanostructures is a promising strategy to tailor their physical and chemical properties. A variety of metal nanostructures with well-defined morphology have been obtained e.g. spheres, triangle, cubes, octahedrons, rods, and plates.

Recently, metal nanostructures with complex three dimensional (3D) surface morphology, which are often referred to as nanoflowers or nanostars in literature, have received considerable attention due to their excellent performance as SERS (Surface Enhanced Raman Scattering) substrates.

[1] Further, for a metal nanostar, the hybridization of plasmons of the core and tips could dramatically increase the excitation cross section and the electromagnetic field enhancements of the tip plasmons, which results in better SERS performance. [2] The main purpose of our work is the fabrication of nanoscopic systems leading to high electromagnetic field intensifications. The strategy for obtaining these systems has been the preparation of anisotropic NPs with special morphologies leading to high field enhancement, as triangular nanoprisms and nanostars. Progress has been made in a very special way to develop protocols for the preparation of silver nanoshaped nanoparticles, which were not prepared so far in silver.

These nanoparticles have a larger number of advantages in relation to gold, since Ag is more efficient in SERS, because of the greater intensification factor, and because of their wider range of activity, as the Ag NPs exhibit plasmon

resonances in the visible spectrum and the nearinfrared. In addition, the protocols of preparation of Ag nanostars were aimed at avoiding the use of surfactants, which are normally used in the preparation of Au nanostars, since these substances prevent the approach of the analyte to the surface, thus decreasing the efficiency of these systems in spectroscopy. In this work we describe the one-step colloid synthesis of silver nanostars and their characterization by spectroscopic and microscopic techniques (Extinction spectroscopy, SERS, TEM and SEF).

Two nanostar types have been fabricated. One of them by synthesis in one step of chemical reduction of nitrate silver solution with neutral hydroxylamine (NS-Ag). The second one, by synthesis in two steps adding gold solution to the first Ag nanostars and reducing with citrate at 1% at 100ยบC (NS-Ag@Au).

Figure 1 shows the TEM images (inset) and the extinction spectra of both colloids. In particular, the NS-Ag@Au nanoparticles have a thin uniform shell of gold coating the silver core. Extinction spectra of these nanoparticles show a big background at high wavelengths indicating a high size and shape distribution with many different numbers of tips, in both cases. The extinction peak about 535 nm in the case of NS-Ag@Au is indicative the presence of gold shell in the nanoparticles.

In order to test these nanostar morphologies as plasmon surfaces, Congo Red (CR) and Thioflavine (ThT) dyes were characterized by vibrational spectroscopy (IR, Raman, SERS) and SEF. CR and ThT are used as histological dyes for staining the peptide _-amyloid, which is a pathologically aggregated form of protein and found in some

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Figure 1 Extinction spectra and TEM (inset) images of NS-Ag and NSAg@Au nanoparticles.

Acknowledgements: This work has been supported by the Spanish Ministerio de Econom铆a y Competitividad (grant FIS2010- 15405) and Comunidad de Madrid through the MICROSERES II network (grant S2009/TIC-1476). A.G. - L. also acknowledges CSIC and FSE for a JAE-predoctoral scholarship.

References [1] X.S. Shen, G.Z. Wang, X. Hong, W. Zhu. Phys.

Chem. Chem. Phys., 11 (2009) 7450-7454.

[2] V. Giannini, R. Rodriguez-Oliveros, J.A. Sanchez-Gil. Plasmonics, 5 (2010) 99-104.

[3] T. Miura, C. Yamamiya, M. Sasaki, K. Suzuki, H. Takeuchi. J. Raman Spectrosc., 33 (2002) 530 535.

[4] S.A. Hudson, H. Ecroyd, T.W. Kee, J.A. Carver.

FEBS Journal, 276 (2009) 5960-5972.

Figure 2 SERS spectra with NS-Ag and NS-Ag@Au without aggregation for (a) RC and (b) ThT. 位exc. = 532 nm. Spectra normalized to the water band.

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human diseases including Alzheimer and prion diseases. [3,4] Figure 2 shows the SERS spectra of RC and ThT obtained using NS-Ag and NS-Ag@Au as SERS substrates. As can be seen, intense SERS bands of both RC and ThT were obtained in the fabricated nanostars. However, the intensity was higher when using NS-Ag@Au. In addition, the SERS enhancement is much higher in the case of RC. The higher activity of the latter nanoparticles is attributed to the higher extinction of light occurring on NS-Ag@Au due to the better match of the extinction plasmon with the exciting laser.

Moreover, the larger SERS intensity obtained for RC can be explained on the basis of the higher resonance effect obtained for this dye at the 532 nm excitation.

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Oral Multi-purpose X-ray diffractometer platform with versatile SAXS/WAXS options

Jan Gertenbach 1 J. Bolze 2 V. Kogan D. Beckers1 1 P. Munk and 1 M. Fransen

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PANalytical B.V., 7602 EA Almelo, The Netherlands DANNALAB B.V., 7543 BK Enschede, The Netherlands

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jan.gertenbach@panalytical.com

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A multi-purpose laboratory X-ray diffractometer was configured for advanced small angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS) measurements. The modular concept of the instrument incorporates pre-aligned optical components and sample stages and thus allows for a quick and easy reconfiguration for a wide variety of applications.

The high-end, user-friendly SAXS/WAXS setup is compact and includes an evacuated beam path. It enables measurements in an angular range of 0.08 – 78° 2θ and is also suitable for weakly scattering, dilute samples. Basic 2-dimensional (2D) SAXS experiments can also be undertaken.

The EasySAXS software offers a user-friendly, comprehensive toolbox for data analysis.

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Oral Design of an efficient Graphene-based TiO2 nano-composite for photocatalytic removal of pharmaceuticals from water

Zahra Gholamvand 2 K. Nolan 1 J. Tobin A. Morrissey3

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zahra.gholamvand@dcu.ie 1

School of Biotechnology, Dublin City University, Dublin 9, Ireland.

School of Chemical Sciences, Dublin City University 3 Oscail, Dublin City University, Dublin 9, Ireland, Dublin 9, Ireland

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effect of chemical bonding between TiO2 and graphene, all composites were prepared by in-situ synthesis of TiO2 in the solution on graphene and also physical mixing of pre-synthesised bare TiO2 and graphene. The composite materials were systematically evaluated for the degradation of Diclofenac, Carbamazepine and Famotidine under both UV and visible light irradiation in a designed immersion well reactor shown in figure 1(f).

Results and Conclusions In-situ synthesis of TiO2 nanostructures on GO yields uniform composite with strong physical and chemical binding without any free particle (figure 2(a),(c)(d)) which enhances the photocatalytic efficiency when compared to simple solution mixing and pure TiO2 (figure 1b). In natural pH TiO2 forms solid fibres during the hydrothermal process which grow uniformly on the surface of GO with ‎an average length of 1-2 micron and an average diameter of 10-20 nano meter (figure 1d). In highly alkaline solution, they form nanotubes on the surface of GO (figure 2c). ‎The highest photocatalytic performance under UV and visible was obtained for in-situ synthesised TiO2 nanotubes/GO composite. According to TEM, Raman spectroscopy, and BET analysis data, the superior photocatalytic enhancement was attributed to 1) the optimal assembly and interfacial coupling between the reduced GO sheets and TiO2 nanotubes, 2) the increase of surface-‎adsorbed reactant species due to large surface area (350 m2/g comparing 60 m2/g for P25) and meso-porous structure of nanotubes, 3) ‎the lower rate of photogenerated electron–hole pairs recombination due to the high conductivity of graphene, 4) the extension of the light ‎absorption range due to carbon doping in TiO2 during the hydrothermal process.‎ Almost 100% degradation of famotidine pollutant was achieved

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The presence of pharmaceutical compounds in the aquatic environment and their possible ‎effects on living organisms has emerged as a serious environmental concern particularly as conventional wastewater treatments only can partially remove them. The use of photocatalysts, particularly TiO2, has been considered one of the most cost and energy efficient clean technologies for use as tertiary wastewater treatment. The aim of this study is to find the most efficient TiO2/graphene nano-composite which is easy to process and able to purify water under solar light irradiation. The combination of TiO2 and reduced graphene oxide which ‎possess excellent adsorption, transparency, conductivity and controllability promises to simultaneously enhance pollutant adsorption and charge transportation to ‎facilitate photodegradation of the pollutants.

Facile and reproducible routes to obtain chemically ‎bonded TiO2/graphene composites have been reported in the literature and their ability to degrade pharmaceuticals pollutants from water has been evaluated. The role of reduced graphene oxide platform in prohibiting electron-hole recombination and stimulating visible light activity of structurally controlled TiO2 photocatalyst (zero, one, and three-dimensional nano-structures shown in figure 1a) were also demonstrated. The effect of the dimensionality of TiO2 on photocatalytic performance, surface area, adsorption, and carrier transfer of the composites were investigated by preparing the homogeneous distributions of four different morphologies of TiO2 including nanoparticles, nanotubes, nanofibers and meso-porous beads via in-situ sol-gel method, alkaline hydrothermal method, solvothermal and sol-gel/solvothermal method respectively. This was followed by 2 h of post-thermal annealing at 400 C in Argon atmosphere. In order to study the

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after 40 min irradiation by UV and 100 min by visible light (figure 3-D1). In summary when ‎graphene is hybridized with TiO2, it can slow down the recombination of photo-‎generated electronhole pairs, increasing charge transfer rate of electrons and surface-adsorbed ‎amount of chemical molecules via π–π interactions which causes the enhancement in photocatalytic functionality of the composite [1].

References [1] P. V. Kamat. (2010 01/21). The Journal of Physical Chemistry Letters 1(2), pp. 520-527.

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Figure 1: of TiO2/graphene composite (a), the effect of synthesis method on photocatalytic efficiency (b).

Figure 2: SEM and TEM images of (a) sol-gel synthesised TiO2/GO, (b) solution mixing of P25/GO, (c): in-situ hydrothermally synthesised TiO2 nanotubes on RGO, (d): hydrothermally synthesised TiO2 nanofibres/GO, (e): 3D network of TiO2 beads/GO, (f): schematic image of immersion well Photocatalytic reactor.

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Figure 3: UV and visible light photocatalytic degradation of famotidine

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Invited Radiolabelling of Nanoparticles using Cyclotron-Based Techniques

Neil Gibson

neil.gibson@jrc.ec.europa.eu Institute for Health and Consumer Protection, Joint Research Centre, Ispra (VA) Italy

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Figure 1: The Scanditronix MC-40 Cyclotron at JRC Ispra, and the target capsule and holder used for direct ion-beam radiolabelling of dry nano-particulate powders.

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Radiolabelled nanoparticles can be used for tracing studies of relevance to many fields, such as nanomedicine, nanotoxicology, environmental tracing, occupational health, etc. Various methods for nanoparticle radiolabelling exist, each with advantages and disadvantages for particular studies. An outline is presented here of cyclotronbased techniques that can be used to directly radiolabel engineered nanoparticles, as well as some methods for synthesis of labelled nanoparticles using cyclotron-generated radioactive precursor materials. A basic outline is given of how cyclotron accelerators can be used to induce nuclear reactions, the characteristics of different radio-isotopes and their practical applicability for tracing, and what effect the direct ion-beam radiolabelling process might have on the nanoparticles themselves. In particular, the issues of thermal effects and radiation damage effects are addressed.

Selected details are presented regarding some of techniques applied in our laboratories and those of collaborating groups, including direct light-ion activation of dry nanoparticle samples, neutron activation using a cyclotron ion-beam driven source, preparation of activated precursors and physical nanoparticle synthesis methods, recoillabelling via ion bombardment of mixed powders, and radiochemical synthesis of nanoparticles using radioactive precursors.

Invited New two-photon based nanoscopic modalities and optogenetics

DTU Fotonik, Dept. of Photonics Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark www.ppo.dk www.optorobotix.com

The science fiction inspired shrinking of macroscale robotic manipulation and handling down to the micro- and nano-scale regime open new doors for exploiting the forces and torques of light for micro- and nanobiologic probing, actuation and control [1-3]. A generic approach for optimizing light-matter interaction on these scales involves the combination of optimal light-sculpting [4] with the use of optimized shapes in micro-robotics structures [5]. Micro-fabrication processes such as two-photon photo-polymerization offer threedimensional resolutions for creating customdesigned monolithic microstructures that can be equipped with optical trapping handles for convenient mechanical control using only optical forces [6].

These microstructures illustrated below can be effectively handled with simultaneous top- and side-view on our BioPhotonics Workstation to undertake six-degree-of-freedom optical actuation of two-photon polymerised microstructures equipped with features easily entering the submicron-regime.

Aided by European collaborators who fabricated test structures with built-in waveguides for us, we were able to put the idea of optically steerable freestanding waveguides – coined: wave-guided optical waveguides - to the test using our BioPhotonics Workstation [7]. We also propose using these techniques for generating two-photon real-time spatially sculpted light for the strongly emerging areas of neurophotonics and optogenetics [4].

[2] [3] [4]

[5]

[6]

[7]

Jesper Glückstad

jesper.gluckstad@fotonik.dtu.dk

microenvironments for biomedical studies," Optics Express 17, 6578-6583 (2009).

J. Glückstad, “Sorting particles with light,” Nature Materials 3, 9-10 (2004).

J. Glückstad, “Optical manipulation: Sculpting the object,” Nature Photonics 5, 7-8 (2011).

E. Papagiakoumou, F. Anselmi, A. Begue, V. de Sars, J. Glückstad, E. Isacoff, V. Emiliani, “Scanless two-photon excitation of channelrhodopsin-2,” Nature Methods 7, 848-854 (2010).

D. Palima, A. R. Bañas, G. Vizsnyiczai, L. Kelemen, P. Ormos, and J. Glückstad, "Wave-guided optical waveguides," Opt. Express 20, 2004-2014 (2012).

D. Palima and J. Glückstad, “Gearing up for optical microrobotic manipulation: mechanical actuation of synthetic microstructures by optical forces,” Laser & Photonics Reviews (2013).

H. Ulriksen, J. Thøgersen, S. Keiding, I. P.-Nielsen, J. Dam, D. Palima, H. Stapelfeldt, J. Glückstad, "Independent trapping, manipulation and characterization by an all-optical biophotonics workstation," J. Eur. Opt. Soc-Rapid 3, 08034 (2008).

Figures

References

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[1] P. Rodrigo, L. Kelemen, D. Palima, C. Alonzo, P. Ormos, and J. Glückstad, "Optical microassembly platform for constructing reconfigurable

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Invited Dielectric properties of biological samples measured at the nanoscale: from single bacteria to single viruses

Gabriel Gomila

gabriel.gomila@ub.edu Institut de Bioenginyeria de Catalunya (IBEC) and Universitat de Barcelona, Baldiri I Reixac 11-15, Barcelona (Spain)

[2] Gramse, G., Casuso, I., Toset, J., Fumagalli, L.

[3]

[4]

[5] [6]

[7]

and Gomila, G,. Nanotechnology 20, 395702 (2009).

Fumagalli, L., Gramse, G., Esteban-Ferrer, D., Edwards, M. A. and Gomila, G., Appl. Phys.

Lett. 96, 183107 (2010).

Fumagalli, L., Esteban Ferrer, D., Cuervo, A., Carrascosa, J. and Gomila, G., Nature Materials, 11, 808–816 (2012).

Fumagalli, L., Ferrari, G., Sampietro, M. and Gomila, G., Nano Lett. 9, 1604-1608 (2009).

Gramse, G., Edwards, M., Fumagalli, L. and Gomila, G., Appl. Phys. Lett., 101, 213108 (2012).

Gramse, G., Dols-Pérez, A., Edwards, M., Fumagalli, L. and Gomila, G., Biophysical Journal, 104, 1257-1262 (2013).

NANOBIO&MED 2013

Nanoscale dielectric microscopy (NDM) is a scanning probe microscopy technique that in addition to measure surface topography, enables to measure the local dielectric response (the dielectric constant, εr) of materials with nanoscale spatial resolution (< 50 nm). NDM can be performed in both AC current-sensing or forcedetection mode, and in recent years it has become a well applied technique for the study of dielectric materials [1-3]. Besides its application in materials science, it enables also to quantify the dielectric properties of biological samples and hence to quantitatively investigate electrostatic phenomena in biology. In the present communication, we will introduce nanoscale dielectric microscopy and present recent results obtained in the study of a variety of biological systems ranging from single viruses [4] and single bacteria to supported biomembranes [5]. In particular, we will show that the quantitative nature of the technique enables to develop a novel label-free material identification method based on the measurement of the dielectric response of the samples [4].

Examples include the identification of dielectric nanoparticles of different material composition [4], of single viruses from its empty capsids [4] or of single bacteria of different types. Finally, we will show how this technique can be extended to the liquid environment [6,7] opening a number of important possibilities in the study of electric processes in small scale biological systems References

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[1] Fumagalli, L., Ferrari, G., Sampietro, M. and Gomila, G. Appl. Phys. Lett. 91, 243110 (2007).

Oral Safety Implementation of Nanotechnology for Chemical Enterprises within a Bottom-Up Approach towards Communication

1

S. Hartl 1,2 F. Sinner Ch. Micheletti3 and A. Falk1

sonja.hartl@bionanonet.at

1

BioNanoNet Forschungsgesellschaft mbH, Graz, Austria 2 JOANNEUM RESEARCH- HEALTH, Graz, Austria 3 Veneto Nanotech ScpA, Padova, Italy This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF.

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Within the aim of the Central Europe project NANOFORCE the general objective is to connect public and private organizations, to carry out collaborative and interdisciplinary researches on nanomaterials, and to turn the most promising laboratory results into innovative industrial applications.

To build up a legal advisory board for chemical enterprises starting in nanotechnology, a state of the art report on existing safety procedures and nanotech related legislation was produced to illustrate the existing regulatory framework within the European region. Data sets of lab analysis which are performed on three different nanomaterials will lead to safety data sheets showing how the tested nanomaterials can be produced and professionally used conforming to safety and users guidelines. Results can already be shown generated by standardised in vitro testing methods for human toxicity and ecotoxicological testing for nanomaterials like nano-silver, zinc oxide and titanium dioxide.

In the outline of presenting a transnational guideline on responsible management for researchers and industry, to have a safe and informative set of regulations to be followed when entering the nanotechnology businesses, another focus was laid on the correct implementation of nano-derived products and market placement, also partly focusing on consumer acceptance to be one of the major problems. Furthermore the guideline will help to distribute information on risks and benefits resulting from the use of nanotechnology as one of the key enabling technologies.

Additionally the regions attractiveness for investors in nanotechnology within the CE area is presented by business plan incorporating information on micro-economic data, infrastructure and funding situation. This is needed

to foster the interactions between research and industry and additionally strengthened by a supervised online platform focusing on start-up collaborations between researchers and industry.

This “NanoDeals- Generator” platform provides expertise tailored to individual needs and support innovative SMEs in launching new joint nanotechnology initiatives. Until now several experts have been registered and proposed their project ideas and NANOFORCE is providing a match-making facility to boost the communication activities. To evaluate the proposals a technology rating methodology for the assessment, validation and evaluation of “NanoDeals” has been developed following the “three-pillar bridge” presented by the High-Level Expert Group on Key Enabling Technologies, focusing on technology research, product demonstration and competitive manufacturing.

Within this contribution and together with the current state of the art on regulations to be used for nanomaterials, necessities in regulation of nanomaterials will be presented. Preliminary test results in the field of nanosafety will be shown on different used and produced nanomaterials and directly provided by companies. Possible market barriers and including strategies to overcome these barriers are going to be presented within the NANOFORCE transnational guideline in terms of benefits resulting from nanotechnologies. In addition to this the “NanoDeals-Generator” online platform and the proposal of a business plan will be shown to outline the projects output - to fill the gap between more and less experienced regions and to turn investments in R&D into industrial innovations.

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Oral

Automated particle tracking (APT) for simultaneous zeta potential-, size distribution and concentration analysis of exosomes

Clemens Helmbrecht 2 K. de Miroschedji 2 A. -K. Ludwig B. Giebel2and 1 H. Wachernig

1

1

Particle Metrix GmbH, Neudiessener Str. 6, D-86911 Diessen, Germany Institute for Transfusion Medicine, University Hospital Essen, Hufelandstr. 55, 45122 Essen, Germany

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positions within the electro-optical cell to enhance statistical significance. As the particles are visualized, influences affecting the quality of the measurement such as agglomeration, fluctuation of concentration and background noise due to precipitation are better detectable by APT than with any other indirect characterization method.

Particularly with regard to samples of low exosome concentration, the analysis of samples with particle concentrations as low as 0.5 million particles per mL can be performed.

In summary, automated measurement of size, zeta potential and concentration of particles is the outcome of one simple measurement sequence.

The analysis of several thousands of single particles is completed within minutes. Results on this technique will be demonstrated on selected exosome samples

References [1] Ludwig, A. K., Giebel, B., Exosomes: Small Vesicles Participating in Intercellular Communication, Int J Biochem Cell Biol.

(2012), 44, 11-5.

[2] Crocker, J. C., Grier, D. G., Methods of Digital Video Microscopy for Colloidal Studies, J. Colloid Interf Sci. (1996) 174, 298-310.

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Exosomes are extracellular vesicles between 30 and 170 nm in size range and occur naturally in bodyfluids. Research about the role of exosomes as transmitters of information between cells is a fast growing field which could open up the door to new approaches in diagnosis and therapy [1].

Research into this new field has been aggravated by the lack of techniques suitable for exosome characterization in buffers of high ionic strength.

Direct 2D light scattering of liquid suspensions is an attractive instrument to assist researchers on the quantification of particle size, zeta potential and concentration. By tracking the 90째 scattering light of particles while undergoing Brownian migration, the particle size is derived by applying the Stokes - Einstein equation [2]. Trajectories of several thousands of single particles of the same sample are analyzed resulting in a representative particle size distribution (PSD) of high resolution (Fig. 1). The agglomeration of exosomes in the presence of the high ionic strength of the phosphate buffer (pH 6.5) resulted in a shift of the PSD towards larger hydrodynamic particle size. The electrokinetic properties of charged particles, i.e. electrophoretic mobility and zeta potential are determined by microelectrophoresis. In microelectrophoresis, the migration of particles in an electrical field is recorded. Electrophoretic mobility and zeta potential are calculated from the trajectory data by an automated algorithm. Fig. 2 shows examples of zeta potential distributions of exosomes determined in different buffers.The bench-top system is equipped with an automated start-up routine. After performing of auto-focus, auto-alignment and check of cell quality, the system is ready for measurements. Multiple measurements of concentration, particle size and zeta potential can be carried out in up to 11

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2

Figures

Figure 1: Effect of agglomeration of Exosomes isolated from BMBO cell line in phosphate buffer (pH 6.5) after 2 and 8 min of preparation.

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Figure 2: Zeta potential distributions of more than 400 single particles of each sample measured by automated particle tracking.

Aquisition time was less than 2 min. actor.

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Oral Ultrafast laser spectroscopy of molecular tweezers

1

Wawrzyniec Kaszub 2 2 P. Uriac , B. Legouin 3 3 J. Graton , D. Jacquemin E. Hitti3and 1 M. Lorenc

1

IPR, UMR UR1-CNRS 6251, 263 av. Du General Leclerc, 35042 Rennes, France ISCR - UMR 6226, 2 Avenue du Pr. Leon Bernard CS 34317, 35043 Rennes, France CEISAM UMR CNRS 6230, Faculte des Sciences & des Techniques de Nantes 2, rue de la Houssiniere, BP 92208, 44322 Nantes, France 2 3

[6] J. Graton et al., J. Phys. Chem. (2012).

[7] J. Graton et al., Chem. Phys. Lett. (2012).

Figures

Figure 1: Molecular tweezer synthetized with (1R,2R)-1,2diaminocyclohexane as spacer and two molecules of (+)-usnic acid as pincers [4].

NANOBIO&MED 2013

Femtosecond laser pulses open new perspectives to the ultrafast science, especially in that they allow controlling and observing molecular materials. Recent studies on molecular nanocrystals showed that pump-probe spectroscopy is an insightful method delivering information on the transient states. The same method was applied to the study of molecular tweezers, we present here.

A molecular tweezer, which is essentially a hostguest pair of molecules, is a simple and efficient model to study and understand molecular recognition and self-assembly by Ď&#x20AC; - Ď&#x20AC; interaction.

These non-covalent and hydrophobic interactions are involved in material science, catalysis and especially in biological processes and medical chemistry. A more recent and promising application of host-guest recognition is the design of molecular machines. In this context we have studied Pi0 and TNF complex with ultrafast laser spectroscopy, with the main goal being to reveal the mechanisms leading to the locking and unlocking of the guest by the host. The long term goal would be the laser control of such and related processes, and also design of functionalizable molecular tweezers.

maciej.lorenc@univ-rennes1.fr

References

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[1] R. Bertoni et al., Angew. Chem. Int. Ed. 51 (2012) 7458.

[2] C. D'Amico et al., J. Phys. Chem. C 116 (2012) 3719.

[3] M. Lorenc et al., Phys. Rev. Lett. 103 (2009) 028301.

[4] B. Legouin et al. Org. Lett., 11, (2009) 745.

[5] N. Ruangsupapichat et al., Nature Chemistry 3 (2011) 53.

Invited Sébastien Lecommandoux

Biomimetic polypeptide and polysaccharide based polymersomes for therapy and diagnosis

lecommandoux@enscbp.fr Université de Bordeaux, IPB-ENSCBP, 16 avenue Pey Berland, 33607 Pessac Cedex, France, CNRS, Laboratoire de Chimie des Polymères Organiques, UMR5629, Pessac, France

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Polymer vesicles (polymersomes) are among the most attractive systems for drug delivery applications. Actually, vesicles obtained by selfassembly of block copolymers are expected to overcome some of the current limitations in drug delivery, allowing the development of robust nanocontainers of either hydrophilic or hydrophobic species. In addition, the development of macromolecular nanodevices that can be used within the living body implies that sensors detecting chemical signals -such as ions, enzymes or pH changes- and generating internal signals or appropriate responses be integrated in the macromolecular system [1]. The use of peptide and saccharide building blocks in the copolymer structure would allow both controlling the selfassembled structure and the resultant biofunctionality.

We report an overview on the self-assembly in water of amphiphilic block copolymers into polymersomes, and their applications in loading and controlled release of both hydrophilic and hydrophobic molecules and biomolecules. We pay special attention to polysaccharide and polypeptide-based block copolymer vesicles that we have studied these recent years in our group [2,3]. These newly developed copolymers that mimic the structure and function of glycoproteins represent an example of the effectiveness of a biomimetic strategy in implementing materials design [4]. In addition, magnetic polymersomes, including iron oxide γ-Fe2O3 nanoparticles are currently investigated, together with their potential applications as contrast agent for imaging and as therapeutic nanoparticles using hyperthermia [5]. Exciting and very promising results about their therapeutic evaluation for tumor targeting and in vivo tumor regression studies will be presented [6].

Finally our recent advances in using “biomimicry approaches” to design complex, compartmentalized materials will be proposed [7].

We demonstrate the formation of compartmentalized polymersomes with an internal «gelly» cavity using an original and versatile emulsion-centrifugation process. Such a system constitutes a first step towards the challenge of structural cell mimicry with both “organelles” and “cytoplasm mimics”. This study constitutes major progress in the field of structural biomimicry and will certainly enable the rise of new, highly interesting properties in the field of high-added value soft matter, especially in controlled cascade (bio) reactions

References [1] Garanger, E.; Lecommandoux, S. Angew.

Chem. Int. Ed. 2012, 51, 3060-3062.

[2] (a) Sanson, C.; Schatz, C.; Le Meins, JF.; Soum, A.; Thevenot, J.; Garanger, E. Lecommandoux, S. J. Control. Release (2010), 147, 428. (b) Sanson, C.; Schatz, C.; Le Meins, JF.; Brulet, A.; Soum, A.; Lecommandoux, S. Langmuir (2010), 26, 7953. (e) Sanson, C.; Le Meins, JF.; Schatz; Soum, A.; Lecommandoux, S. Soft Matter (2010), 6, 1722.

[3] (a) Schatz, C.; Louguet, S.; Le Meins, JF.; Lecommandoux, S. Angew. Chem. Int. Ed. (2009) 48, 2572. (b) Upadhyay, K.K.; Le Meins, JF.; Misra, A.; Voisin, P.; Bouchaud, V.; Ibarboure, E.; Schatz, C.; Lecommandoux, S. Biomacromol. (2009), 10, 2802 [4] (a) Bonduelle, C.; Huang, J.; Ibarboure, E.; Heise, A.; Lecommandoux, S. Chem. Commun.

2012, 48, 8353. (b) Huang, J.; Bonduelle, C.;

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Thévenot, J.; Lecommandoux, S.; Heise, A. J. Am. Chem. Soc. 2012, 134, 119.

[5] (a) Sanson, C.; Diou, O.; Thevenot, J.; Ibarboure, E.; Soum, A.; Brulet, A.; Miraux, S.; Thiaudiere, E.;Tan, S.; Brisson, A.; Dupuis, V.; Sandre, O.; Lecommandoux, S. ACS Nano (2011), 5, 1122. (b) Oliveira, H.; Pérez-Andrés, E.; Thevenot, J.; Sandre, O.; Berra, E. ; Lecommandoux, S. J. Control. Release (2013), ASAP (doi: 10.1016/j.jconrel.2013.01.013).

[6] (a) Upadhyaya, KK.; Bhatt, A.N.; Mishra, A.N.; Dwarakanath, B. S.; Jain, S.; Schatz, C.; Le Meins, JF.; Farooque, A.; Chandraiah, G.; Jain, AK.; Misrac, AK.; Lecommandoux, S. Biomaterials (2010), 31, 2882. (b) Upadhyay, Mishra, AK.; Chuttani, K.; Kaul, A.; Schatz, C.; Le Meins, JF.; Misra, A.; Lecommandoux, S. Nanomedicine (2012), 8, 71.

[7] (a) Marguet, M.; Edembe, L.; Lecommandoux, S. Angew. Chem. Int. Ed. 2012, 51, 1173. (b) Marguet, M.; Sandre, O.; Lecommandoux, S. Langmuir 2012, 28, 2035. (c) Marguet, M.; Bonduelle, C.; Lecommandoux, S. Chem. Soc. Rev. 2013, 42, 512-529.

Oral Cyclic measurements of DPPC monolayers at low surface tensions

Biolin Scientific, Tietäjäntie 2, FI-02130 Espoo, Finland

Pulmonary surfactants cover the alveoli of the lungs and have a vital function in making the process of breathing easy. During inhalation, the surfactant reduces the surface tension of tissue by a factor of about 15. During exhalation, the surface area of the alveoli decreases making the surfactant even more concentrated on the surface. It is known that the highly ordered solid phase of dipalmitoylphosphatidylcholine (DPPC) sustains the near-zero surface tension on the alveoli during exhalation [1]. In order to model the actual surfactant behavior in the alveoli, measurements at near-zero surface tensions are needed.

Several groups have investigated the behavior of DPPC monolayers under low surface tensions using Langmuir troughs [2, 3], but with a conventional Langmuir trough it is challenging to measure nearzero surface tensions. We have shown that the compression speed in a Langmuir trough has a distinct effect on the layer formation of DPPC at low surface tensions and temperatures ranging from 20 ºC to 37 ºC. Now we further expand this observation by showing controlled cyclic measurements of DPPC at low surface tensions. The measurements were done on ultrapure water surface at temperatures of 20 ºC, 30 ºC and 37 ºC using a Langmuir trough equipped with a ribbon barrier to prevent monolayer leakage.

The measurements show reliable compression measurements of natural phospholipid surfactants at surface tensions down to 15 mN/m. The measurements can be further expanded to examine phospholipid reactions with nanoparticles, phase transitions and the selective enrichment process of DPPC on the alveoli surface

Kaisa E. Lilja J. Välimaa

kaisa.lilja@biolinscientific.com

[3] Zhang, H.; Wang, Y. E.; Fan, Q.; Zuo, Y. Y. Langmuir 27 (2011) 8351.

References

334

[1] Zuo, Y. Y. J. Appl. Physiol. 102 (2007) 1733.

[2] Xicohtencatl-Cortes, J.; Mas-Oliva, J.; Castillo, R. J. Phys. Chem. B 108 (2004) 7307.

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Invited Biosensing with Gold Nanoparticles

Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia, Spain Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain

llizmarzan@cicbiomagune.es

[3] R.A. Alvarez-Puebla, A. Agarwal, B.P. Khanal, P.

Aldeanueva-Potel, E. Carbó-Argibay, N. PazosPérez, E.R. Zubarev, N.A. Kotov, L.M. LizMarzán PNAS 108 (2011) 8157.

NANOBIO&MED 2013

Metal nanoparticles display very interesting optical properties, related to localized surface plasmon resonances (LSPR), which give rise to well-defined absorption and scattering peaks in the visible and near-IR spectral range. Such resonances can be tuned through the size and shape of the nanoparticles, but are also extremely sensitive towards dielectric changes in the near proximity of the particles surface.

Therefore, metal nanoparticles have been proposed as ideal candidates for biosensing applications.

Additionally, surface plasmon resonances are characterized by large electric fields at the surface, which are responsible for the so-called surface enhanced Raman scattering (SERS) effect, which has rendered Raman spectroscopy a powerful analytical technique that allows ultrasensitive chemical or biochemical analysis, since the Raman scattering cross sections can be enhanced up to 10 orders of magnitude, so that very small amounts of analyte can be detected. In this communication, we present several examples of novel strategies to employ colloidal nanostructures comprising gold or silver and silica in various morphologies, as substrates for ultrasensitive detection of a wide variety of analytes, including cancer markers, drug metabolytes and scrambled prions.

Luis M. Liz-Marzán

References [1] L. Rodríguez-Lorenzo, R. de la Rica, R. Alvarez-

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Puebla, L.M. Liz-Marzán, M.M. Stevens Nature Mater. 11 (2012) 604.

[2] M. Sanles-Sobrido, L. Rodríguez-Lorenzo, S. Lorenzo-Abalde, A. González-Fernández, M.A. Correa-Duarte, R.A. Alvarez-Puebla, L.M. LizMarzán Nanoscale 1 (2009) 153.

Invited Skin applications of Atomic Force Microscopy

Gustavo S. Luengo

gluengo@rd.loreal.com L’Oréal Recherche and Innovation, Aulnay sous Bois, France

The skin surface can be observed with different methods more or less invasive. Atomic Force Microscopy (AFM) in vitro or ex-vivo allows a good resolution of the morphology of skin, not limited by the wavelength of light. In addition mechanical and chemical information is possible thanks to the physical interaction of a small nanometric probe on the surface.

This presentation will show some of our recent studies on skin applications using this technology.

In particular we will comment experimental aspects that are critical for performing this type of experiments from sample preparation to protocols of measurements (ambient, water, dry conditions, etc.).

We will comment the specific morphological aspects like the micro topography of skin, the influence of age, the visualization of skin components. A special consideration will be given to the mechanical characterization of corneocytes, main constituents of the stratum corneum (outermost layer of skin). Their physical characterization from a elastic Young modulus determination to friction studies Finally we will show our current efforts to have access to chemical information by the use of modified AFM tips for protein recognition.

force microscopy. Experimental Dermatology 19 (11):1014-1019, 2010.

[3] A. Potter, Gustavo S. Luengo, R. Santoprete and B. Querleux “Stratum Corneum Biomechanics” Ch. 16 in Skin moisturization V. Rawlings and J. J. Leyden Eds.., Informa Healthcare, 2009.

References [1] W. Tang and B. Bhushan. Adhesion, friction

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and wear characterization of skin and skin cream using atomic force microscope. Colloids Surf.B Biointerfaces 76 (1):1-15, 2010.

[2] Christian Rankl, Rong Zhu, Gustavo S. Luengo, Mark Donovan, Nawel Baghdadli, and Peter Hinterdorfer. Detection of corneodesmosin on the surface of stratum corneum using atomic

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Oral Silica nanostructures toxicity assessment and their potential for biomedical applications

Maria Ada Malvindi

1

V. Brunetti1 G. Vecchio2 A. Galeone1 V. De Matteis1 R. Cingolani3 and P. P. Pompa1

1

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ROS. We found that SiO2NPs doped with iron oxide nanoparticles do not induce detectable cytotoxic effects up to 1 nM concentration (Fig.3b) with negatively charged NPs exerting the higher toxicity. This is likely associated to the nanoparticles degradation in lysosomal environment.

Overall, we demonstrate that SiO2 nanostructures are quite safe in vitro and have promising potential in biomedical applications.

References [1] M.A. Malvindi et al., Nanoscale, 2012, 4; 4(2), 486-495.

[2] G. Bardi et al., Biomaterials, 2010, 31, 65556566.

Figures

Figure 1: Representative TEM images of three sizes of SiO2NPs: 25, 60 and 115 nm.

Figure 2: a) Viability of A549 cells 48 and 96 h after the exposure to increasing doses evaluated of 25 nm SiO2NPs by the WST-8 assay; b) In vitro silencing of tGFP expression.

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Silica nanoparticles are widely used in various industrial fields and recently, they have been exploited also for biomedical research. The impact of SiO2NPs on human health and the environment is thus of great interest. Nowadays, the overall evaluation of the toxicity/biocompatibility of SiO2NPs is extremely difficult, owing to controversial results in the literature and to the lack of standard procedures and/or insufficient characterization of the nanomaterials in biological systems. Therefore the biocompatibility needs to be documented in greater detail. In this study we evaluated the toxicity of different silica nanostructures, both pure and quantum dots (QDs)- or iron oxide-doped, and studied their potential applications in gene delivery. We performed a systematic in vitro study to assess the biological impact of pure SiO2NPs, by investigating 3 different sizes (Fig.1) and 2 surface charges in 5 cell lines. We analyzed the cellular uptake and distribution of the NPs along with their possible effects on cell viability, membrane integrity and generation of reactive oxygen species (ROS). We observed that all the investigated SiO2NPs do not induce detectable cytotoxic effects (up to 2.5 nM concentration) in all cell lines (Fig.2a). Once having assessed the biocompatibility of SiO2NPs we evaluated their potential in gene delivery, showing their ability to bind, transport and release DNA, allowing the silencing of a specific protein expression (Fig.2b)1. The biocompatibility of SiO2NPs and their gene carrier performance were also evaluated and confirmed in primary neuronal cells2. Finally, we investigated the toxicity of silica nanoparticles doped with iron oxide nanocrystals.

We tested nanoparticles with two surface charges in two cell lines by evaluating their effect on cell viability, cell membrane integrity and induction of

mariada.malvindi@iit.it

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Istituto Italiano di Tecnologia, Center for Bio-Molecular Nanotechnologies@Unile, Via Barsanti,1 â&#x20AC;&#x201C; 73010 Arnesano (Lecce), Italy Telephone number: +39 0832-1816248, Fax: +39 0832-1816230 2 Mawson Institute, University of South Australia, Mawson Lakes, SA 5095, Australia 3 Istituto Italiano di Tecnologia, Central Research Laboratories, Via Morego, 30 â&#x20AC;&#x201C; 16136 Genova, Italy

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Figure 3: a) SiO2NPs doped with iron oxide NPs; b) Viability of A549 cells 48 and 96 h after the exposure to increasing doses of SiO2NP doped with iron oxide NPs evaluated by the WST-8 assay; c) Iron release in lysosomal environment.

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Functionalization of silicon dioxide micropillars for biosensing and microarray technology

Lluis F. Marsal M. Alba P. Formentín P. Jacob J. Pallarès and J. Ferré-Borrull

Departament Departament d’Enginyeria Electrònica, Elèctrica i Automàtica, Universitat Rovira i Virgili, Avda Països Catalans 26, 43007 Tarragona (Spain)

lluis.marsal@urv.cat

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These micropillar arrays can be used as microarchitectured substrate for cell capturing and for biosensing. In all the cases the surface have to be functionalized in order to be selective to specific substances [7-8]. To demonstrate the feasibility of the chemical modification, the outer surface of the silicon dioxide micropillars was functionalized by silanization with 3aminopropyltriethoxysilane (APTES). Subsequently, the amine group of APTES is activated by incubation in glutaraldehyde (GTA). Finally, the samples were incubated with fluorescein-labelled bovine serum albumin (BSA-FITC). Figure shows a composed figure of scanning electron microscope (SEM) image of one inverted pyramid with micropillars and a schematic representation of the functionalization of the SiO2 micropillars. The FITC fluorescent labelling of the protein is used to confirm the BSA attachment onto the functionalized SiO2 micropillars. The observation under a fluorescence microscope revealed that the FITC-BSA bounds to the SiO2 micropillars. Figure 3 shows a confocal microscopy image top view of the silicon dioxide micropillars functionalized with APTES, GTA and FITC. Green colour comes from the FTIC-BSA functionalized surfaces.

In conclusion, silicon dioxide micropillar arrays are potential biosensing platforms for molecular detection in biotechnological applications such as the detection of molecular binding events, substrates for cell culture and so on.

Acknowledgements: This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under grant number TEC2012-34397, CONSOLIDER project CSD20070007 and by Generalitat of Catalunya under project 2009 SGR

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Macroporous silicon produced by electrochemical etching has been proved to be a promising material in a broad range of applications due to its versatility and low cost technology [1-3]. One interesting structure that can be obtained from macroporous silicon is silicon dioxide (SiO2) micropillar arrays. The uniformity and geometry of these micropillar arrays rely on the fabrication conditions as the micropillar structure is directly related with the pore geometry of the macroporous silicon. Briefly, these structures can be fabricated from macropores produced by electrochemical etching of n or p-type silicon wafers in hydrofluoric acid (HF) solutions. After the fabrication of macroporous silicon, the samples are thermally oxidized under oxygen atmosphere to obtain a silicon dioxide layer on all the surface. The last step is to remove the silicon dioxide layer on the backside of the wafer and to etch the silicon in TMAH solution to release the micropillars. The oxide within the macropores is resistant to the TMAH etch and silicon ioxide tips begin to appear on the backside of the wafer [4-5].

If the backside of the silicon wafer is patterned by lithographic techniques, we can obtain a platform of silicon dioxide pillar arrays inside truncated micropyramids. Figure 1 shows an example of silicon dioxide micropillar arrays inside of a set of truncated inverted pyramids. The size of the mask together with the etching time determine the dimensions of the pyramid. A large number of these structures can be fabricated on a single wafer and each one of those truncated pyramids can be used for detection of different molecular binding events [6] increasing at the same time the contact area between probes and target molecules due to the presence of the micropillars.

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Oral

References [1] V. Lehmann, Phys. Status Solidi (a), 197 (2003) 13.

[2] V. Lehmann, Electrochemistry of Silicon:

[3]

[4]

[5]

[6] [7] [8]

Instrumentation, Science, Materials and Applications, Wiley-VCH, (2002).

T. Trifonov, A. Rodríguez, L.F. Marsal, J. Pallarès, R. Alcubilla, Sensors and Actuators, APhysical 141 (2008) 662.

T. Trifonov, A. Rodríguez, F. Servera, L.F. Marsal, J. Pallarès, R. Alcubilla, Phys. Status Solidi (a), 202 (2005) 1634.

A. Rodríguez, D. Molinero, E. Valera, T. Trifonov, L.F. Marsal, J. Pallarès, R. Alcubilla, Sensors and Actuators, B-Chemical 109 (2005) 135.

V. Lehmann, Nature Materials 1, (2002) 12.

M.J. Sweetman, C.J. Shearer, J.G. Shapter, N.H. Voelcker, Langmuir, 27 (2011) 9497.

I. Mey, C. Steinem, A. Janshoff, Journal of Materials Chemistry, 22 (2012) 19348.

Figure 3: Confocal microscopy top view of functionalized and fluorescent labelled (APTES + FITC) a) ordered SiO2 micropillars and b) single unattached SiO2 micropillar. The green color indicates the fluorescence of FTIC.

Figures

Figure 1: SEM image of a set of inverted truncated pyramids with disordered SiO2 micropillars.

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Figure 2: SEM image of an inverted truncated pyramid with disordered SiO2 micropillars and schematic functionalization of micropillar.10 μm.

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Oral KTP nanocrystals exhibiting high SHG emission for bio-imaging applications 1

Laboratoire de Physique de la Matière Condensée – Ecole Polytechnique-CNRS, UMR 7643, 91128 Palaiseau Cedex, France 2 Laboratoire de Photonique Quantique et Moléculaire – ENS Cachan & CNRS, UMR 8537, 94235 Cachan, France 3 CEA/CNG, Laboratoire Génomique Fonctionnelle, 91057 Evry, France 4 INSERM 894, Centre Psychiatrie & Neurosciences de l’INSERM, 75014 Paris, France

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1

A. Slablab2 G. Dantelle1, V. Jacques2 A.-M. Lepagnol-Bestel3 S. Perruchas1, P. Spinicelli2 A. Thomas4, D. Chauvat2 M. Simonneau4 T. Gacoin1 and J.-F. Roch2

ludovic.mayer@polytechnique.edu thierry.gacoin@polytechnique.edu jean-francois.roch@ens-cachan.fr

References [1] F. C. Zumsteg, J. D. Bierlein, T. E. Gier, J. Appl.

Phys. 47, (1976) 4980.

[2] L. Le Xuan, C. Zhou, A. Slablab, D. Chauvat, C.

Figures

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Tard, S. Perruchas, T. Gacoin, P. Villeval, J.F.Roch, Small, 4(9) (2008) 1332.

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In the last few decades, numerous works have been devoted to the development of efficient luminescent probes for bio-imaging applications.

KTiOPO4 (KTP), a well-known material for its nonlinear optical properties (especially second harmonic generation) [1] could be a good candidate as nonlinear optical probe because of its SHG excitation windows laying in the near IR range (transparent for biological tissues) and the possibility to determine the crystal orientation allowing orientation tracking [2 ].

We present here the coprecipitation synthesis of single-crystal KTP nanoparticles whose size ranges from 200 nm to less than 30 nm. They can be easily dispersed in water and are stable at physiological pH. Using a pulsed Ti-Sapphire laser at a wavelength of 1020 nm and a standard twophoton microscope combined with an Atomic Force Microscope, non-linear optical properties of these particles are investigated. They exhibit a perfectly stable high SHG signal and their crystalline orientation can be fully determined using the SHG high sensitivity to the polarization of the excitation light. We also show the possibility to use these particles as nonlinear optical probe for biology by introducing KTP nanoparticles into a culture medium with mouse primal neural cells.

Investigations prove that individual KTP nanoparticles can be imaged inside the cell body and the neurites, while the absence of any visible impact on the short term development of the cells indicates their low toxicity at least for our in-vitro experiments.

Ludovic Mayer

Invited Multiple-probe scanning probe microscopy: a potential application to bio-inspired materials research

1

WPI Center for Materials Nanoarchitectonics (MANA), NIMS, 1-1 Namiki, Tsukuba, Ibaraki, Japan 2 Grad. School of Pure and Applied Sciences, Univ. of Tsukuba, 1-1 Namiki, Tsukuba, Ibaraki, Japan

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Multiple-probe scanning tunneling microscope (MP-STM) [1] enables us to investigate, at the nanometer scale, electrical properties of nanomaterials and functions of extended nanosystems as schematically illustrated in Figure 1. So far, MP-STM has been developed and used for characterizing electrical properties of nanomaterials, such as fullerene polymers, selforganized metal silicide nanowires, carbon nanotubes and so on [2]. However, our recent development to convert the MP-STM into MPatomic force microscope (MP-AFM) [3] really opens possibilities to perform MP-scanning probe microscope (MP-SPM) measurements on a variety of materials, ranging from metal, semiconductor, insulator and even biomaterials.

One of the challenging and exciting research which can be done using MP-SPM would be the application of MP-SPM to biology. Since MP-SPM is, in principle, a device equipped with multiple inputs and outputs to/from materials and systems of interest, application of MP-SPM, for example, to a single cell would establish a signal processing cell system. Here, an important thing is to use appropriate probes for detecting signals in biosystems, i.e., molecular signals. Therefore, we have developed a tungsten suboxide probe which greatly enhances Raman scattering from molecules in a solution.

Another example of interesting research is a development of neuromorphic architecture for neural network computation with MP-SPM. One of the major tackles in creating neural network based on silicon technology lies on the difficulty in preparing highly cross-over interconnections between units (some equivalent circuits to mimic neuron cells and synapses). Recently, an inorganic metal compound system was found to form neuromorphic structures [4]. We discuss how our

Tomonobu Nakayama1,2 1 J. Xu 1 R. Creasey 1 Y. Shingaya and 1 M. Aono

nakayama.tomonobu@nims.go.jp

MP-SPM can contribute to the development of neuromorphic network research toward future computation, together with preliminary results in forming bio-inspired neuromorphic network using carbon-based nanomaterials.

References [1] M. Aono et al., OYO Buturi 67 (1998) 1361. (in Japanese).

[2] T. Nakayama et al., Advanced Materials 24 (2012) 1675.

[3] S. Higuchi, O. Kubo, H. Kuramochi, M. Aono

and T. Nakayama, Nanotechnology 22 (2011) 285205.

[4] A.Stieg, A. Avizienis, H. Sillin, C. Martin-Olmos, M. Aono and J. Gimzewski, 24 (2012) 286.

Figures

Figure 1: Possible measurements using scanning tunneling microscopes with (a) single, (b) double, (c) triple, and (d) quadruple probes.

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Invited Structural characterization and mimicking of biological nanostructures in native heterogeneous environment

Niels Chr. Nielsen

ncn@inano.au.dk

Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, Aarhus, Denmark

[3] S. Zhang, M. Andreasen, J. T. Nielsen, L. Lei, E.

H. Nielsen, T. Skrydstrup, F. Besenbacher, N. C. Nielsen, D. E. Otzen, and M. Dong, Proc. Natl.

Acad. Sci. USA, in press (2013).

[4] N. V. Kulminskaya, M. Ø. Pedersen, M. Bjerring, J. Underhaug, M. Miller, N.-U. Frigaard, J. T. Nielsen, and N. C. Nielsen, Angew. Chem. Intl. Ed. 51 (2012) 6891.

[5] C. U. Hjørringgaard, B. S. Vad, V. V. Matchkov, S. B. Nielsen, T. Vosegaard, N. C. Nielsen, D. E. Otzen, and T. Skrydstrup, J. Phys. Chem. B 116 (2012) 7652.

[6] M. N. Burkhardt, R. Taaning, N. C. Nielsen, and T. Skrydstrup, J. Org. Chem. 77 (2012) 5357.

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In the quest for obtaining inspiration from Nature's advanced nano machineries, it is of great interest to establish high-resolution structure information of biological macromolecules in their heterogeneous, native, and functional environment. This is not trivial using traditional high-resolution methods such as X-ray diffraction and liquid-state NMR spectroscopy requiring the molecular entities either being in wellordered 3D crystals or in a state with fast molecular tumbling in solution.

With examples addressing antimicrobial peptides [1], amyloid fibrils [2,3], and the photo antenna system of the chlorosomes in green sulfur bacteria [4], we demonstrate that combinations of solid- and liquidstate NMR spectroscopy, AFM/SPM, SAXS, TEM, cryo-EM, and MRI offers great potential to explore structure and dynamics of proteins residing in functional, heterogeneous environment. In addition to providing fundamental biological insight, these studies motivates the design of artificial nanoscale ion channels (Fig. 1) [5], biomarkers for early-stage detection of dementia [6], and artificial photo receptors.

References [1] J. Dittmer, L. Thøgersen, J. Underhaug, K.

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Figure 1: Artificial antimicrobial ion channel.

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Bertelsen, T. Vosegaard, J. M. Pedersen, B. Schiøtt, E. Tajkhorshid, T. Skrydstrup, and N. C. Nielsen, J. Phys. Chem. B 113 (2009) 6928.

[2] J. T. Nielsen, M. Bjerring, M. D. Jeppesen, R. O. Pedersen, J. M. Pedersen, K. L. Hein, T. Vosegaard, T. Skrydstrup, D. E. Otzen, and N. C. Nielsen, Angew. Chemie Intl. Ed., 48 (2009) 2118, P. Villeval, J.-F.Roch, Small, 4(9) (2008) 1332.

Oral Multifunctional Coordination Polymer Particles for Bio-medical application

1

Fernando Novio 1 P. González-Monje 2 J. Lorenzo and D. Ruiz-Molina1

1

Centro de Investigación en Nanociencia y Nanotecnología, Campus UAB, 08193 Bellaterra (Spain) 2 Unitat d´Enginyeria de Proteïnes i Proteòmica. Institut de Biotecnologia i Biomedicina Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain)

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The development of different techniques to achieve nanomaterials with unusual and enhanced properties compared to traditional materials have afford new systems with interesting applications in areas such as electronics, catalysis, sensing or biomedicine. The coordination polymers are a fascinating family of materials created from supramolecular assembly of metal ions or clusters and organic ligands that act as building blocks to generate a superstructure with genuine and highly tailorable properties. The results obtained in the last years have shown that these systems can be interesting alternative materials for technological uses. The easy of tuning and modification of their properties based on chemical-structural changes allow control rationally their physicochemical properties.

Our principal efford within our research group is to develop an specific kind of coordination polymers particles synthesized at the nanoscale with application in Biomedicine.[1] In this research area there is an special interest in achieve multifunctional platforms that can provide different properties with interest in biomedicine.[2] A posible ideal system would consist in a nano-platform with optimun size and shape to penetrate in different tisues but also to avoid the immunological system, that is be able to encapsulate different active substances, with biosensing properties and active as bioimaging agent. Moreover, the posibility of building these systems containing the active specie as buildingblock open a new approximation to achieve a platform with smart activity and added value.

With this aim, our research group has developed the synthesis of nanoscale polymeric coordination particles (CPPs)1 able to encapsulate a wide variety of substances and materials for biomedical

fnovio@cin2.es

application.[3,4] The last experimental results have afford the synthesis and characterization of smart responsive CCPs able to tune such release upon external stimuli.[5] We will also show our most recent advances for their use not only for delivery but also for bioimaging purposes as well as the possiblity to functionalize them to improve their cell internalization processes, biocompatibility, and targeting directionality for especific recognition.[6] The good physicochemical properties of these nanoplatforms joint to the extremelly low toxicity, make them an interesting alternative to the current systems.

Here we report the synthesis and characterization of CPPs with controllable dimensions (between 40nm-2µm) bearing reactive groups (-COOH, -NH2, etc.) at the surface. Their crystallinity and morphology can be controlled systematically by the proper combination of ligands and metal ions and reaction conditions. Using carbodiimide assisted coupling reactions different active molecules and biomolecules have been attached to the nanoparticles surface confering them a given specific property. In that manner we have been able to graft CPPs with dyes or poly-ethylene glycol derivates, among others. These ligands confer new interesting properties such as fluorescene to follow the cellular internalization of the CPPs or robustness against opsonization processes.

As complementary studies, we have achieved the robust immobilization of these functionalized systems in gold surfaces. This approximation provides interesting platforms to be used in integrate systems with potential uses in biosensing and in clinical diagnosis All these preliminary results joint to the cytotoxicity experiments that shown a very good

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biocompatibility of the resulting functional capsules even for the case of using cobalt metal ions, open new venues for CPPs to be used as multifunctional platforms at biological level.

References [1] . Novio, J. Simmchen, N. Vazquez, L. Amorín,

[3]

[4]

[5]

[6]

Figure 2: a-b) TEM image of iron oxide nanoparticles, c) interaction of the loaded nanoparticles with a magneto, and d) hysteresis loop of encapsulated magnetic nanoparticles

Figure 3: Scheme of fluorescein functionalized CCPs by carbodiimine assisted coupling reaction.

Figures

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[2]

D. Ruiz-Molina, Coord. Chem. Rev. submitted invited paper.

M. De, P. S. Ghosh, V. M. Rotello Adv. Mater.

20, (2008), 4225.

I. Imaz, J. Hernando, D. Ruiz-Molina, D. Maspoch, Angew. Chem. Int. Ed. 48, (2009), 2325.

I. Imaz, M. Rubio-Martínez, L. GarcíaFernández, F. García, D. Ruiz-Molina, J. Hernando, V. Puntes, D. Maspoch, Chem.

Commun., 46, (2010), 4737.

F. Novio, J. Simmchen, J. Ruiz, V. Rodriguez, N. Cutillas, J. Lorenzo, D. Ruiz-Molina, paper in preparation.

F. Novio, P. González-Monje, J. Lorenzo, D. Ruiz-Molina, Angew. Chem. Int. Ed. Engl.

Submitted.

Figure 4: Optical and fluorescence images of the fluorescent nanoparticles internalization.

Figure 1: a) Scheme of CPPs synthesis, b) SEM images of the resulting nanoparticles, and c) TEM image of a drug loaded nanoparticles.

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Figure 5: HR-SEM images of CPPs attached to gold surface.

Invited Singlet Oxygen in Mammalian Cells: Exploiting Nanoscopic Tools in Single Cell Experiments

Peter R. Ogilby

progilby@chem.au.dk

Center for Oxygen Microscopy and Imaging, Department of Chemistry, Aarhus University, Aarhus, DK-8000, Denmark

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Singlet oxygen, the lowest excited electronic state of molecular oxygen, is a â&#x20AC;&#x153;mature citizenâ&#x20AC;? that has been studied for many years from a wide range of perspectives. Among other things, singlet oxygen has a unique chemistry that results in the oxygenation of many organic molecules. In this way, it plays important roles in biology, particularly in mechanisms of cell signaling and cell death.

Singlet oxygen is commonly produced in a photosensitized process wherein light is absorbed by a given molecule (the so-called sensitizer) followed by energy transfer from the excited state sensitizer to ground state oxygen. The production of singlet oxygen in this way is a natural phenomenon (i.e., we live in a world of light, oxygen, and suitable sensitizers).

We have a multi-faceted program in which the behavior of singlet oxygen is examined under conditions and in systems that have, heretofore, been inaccessible. We are particularly interested in developing and exploiting tools that provide unique insight into the mechanistic behavior of singlet oxygen in cells. I will briefly describe our latest work that is relevant to phenomena on the nano-scale: (a) focused two-photon sensitizer excitation to impart spatial selectivity in single cell experiments, (b) protein-encapsulated sensitizers that can be localized in specific intracellular domains, (c) electric fields associated with nanoparticle surface plasmons to enhance radiative transitions in oxygen, and (d) added quenchers to influence diffusion-dependent singlet oxygen deactivation.

Our results indicate that there is still much to be gained from studies of singlet oxygen.

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Invited Enzymes and fluorescent nanoparticles

Valeri Pavlov L. Saa and G. Garrai

vpavlov@cicbiomagune.es CIC BiomaGUNE, Paseo Miramon 182, San Sebastian, Spain

References [1] Saa L., Virel A., Sanchez-Lopez J., Pavlov V., Chem-Eur. J. 16 (2010) 6187.

[2] Saa L., Pavlov V., Small, 8 (2012) 3449.

Figures

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Semiconductor inorganic NPs can be photoexcited to generate electron/hole couples which recombine to yield fluorescent emission of light.

The stable and bright emission of semiconductor NPs arises from quantum confinement effects that occur in nanometer-sized semiconductors hence such NPs are called quantum dots (QDs). QDs modified with antibodies, DNA and small molecules found application as labels in bioanalytical affinity assays and imaging.

Decorated hybrid NPs, iron oxide NPs and nanostructures with an elongated assembly of cores are utilized in magnetic resonance and fluorescence imaging for detection of cancer. The above mentioned analytical systems are based on presynthesized NPs decorated with recognition elements acting as labels or donor/quencher FRET pairs for quantification of enzymatic activities.

Their performance is frequently hindered by high background signals caused by nonspecific adsorption of decorated NPs on surfaces or poor quenching of donor couples. Generation of NPs in situ can address these drawbacks of relevant analytical systems by decreasing the background signals.

We developed some methods employing enzymatically driven formation of CdS QDs. The examples are represented in Scheme 1, Scheme 2, Scheme 3 and Scheme 4.

The above mentioned enzymatic assays demonstrated sensitivity better by one-two orders of magnitude than previously reported assays using commercially available chromogenic substrates

Scheme 1: Assay for acetylchololinesterase (AChE)1.

Scheme 2: Assay for alkalinephosphatase (ALP)1.

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Scheme 3: Assay for glucose oxidase (GOx)2.

Figures

348

Scheme 4: Assay for horseradish peroxidase (HRP)2.

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Invited Molecular nanomechanics in human health

Raul Perez-Jimenez

rperezjimenez@nanogune.eu CIC nanoGUNE Tolosa Hiribidea 76, Donostia-San Sebastian, Spain

[2] Wiita AP, Perez-Jimenez R et al. Nature, 450(7166), 2007, pp 124-127.

[3] Perez-Jimenez R et al. Nat Struct Mol Biol,

16(8), 2009, pp 890-6.

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Mechanical forces play a crucial role in a myriad of biological processes including numerous diseases and disorders [1].

However, molecular nanobiomechanics are barely considered in modern medicine. Our research line focuses on atomic force microscopy (AFM) to investigate the effect of mechanical forces in proteins and enzymatic reactions that are relevant to human pathologies. In the past years, we have investigated how force affects the chemistry of thioredoxins, a class of enzymes that regulate the redox balance in cells. We showed that force regulates their chemistry, revealing several mechanisms for disulfide bond reduction that were hidden in standard bulk assays [2,3]. Importantly, these enzymes seem to be important during HIV-1 infection by reducing disulfide bonds in human CD4, the primary receptor of the virus. Using AFM techniques we have investigated the mechanics of CD4. We observed that force might trigger mechanical unfolding of CD4 and subsequent disulfide bond reduction in CD4 by Trx enzymes.

Further experiments demonstrated, for the first time, that an antibody that blocks HIV-1 infection produces a mechanical effect on CD4 by preventing mechanical unfolding. We suggest that mechanical force might be important during HIV-1 infection which may change our understanding of the mechanism of infection. This observation might offer new avenues to explore novel treatments focused in the mechanics of proteins and enzymes, that is, mechanopharmacology.

References

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[1] Vogel V, Sheetz MP, Nanomedicine. WileyVCH, Wenheim, (2009) pp 235-303.

Oral Multifunctional Nanoplatform for Biomedical Applications 1

Rafael Piñol

Ins. de Ciencia de Materiales de Aragón (ICMA), CSIC–Univ. of Zaragoza, C/ Pedro Cerbuna 10, 50009 Zaragoza, Spain.

2 Departamento de Física and CICECO. University of Aveiro, 3810-193 Aveiro, Portugal.

3 Lab. of Molecular Toxicology, Fac. of Veterinary Medicine, Univ. of Zaragoza, 50009 Zaragoza, Spain.

4 Department of Hematology, Faculty of Medicine, University of Zaragoza, 50009 Zaragoza, Spain.

5 Department of Physics “A. Volta”, University of Pavia, 27100 Pavia, Italy.

6 Laboratoire de Physique et Chimie des Nano-Objets (LPCNO), INSA-University of Toulouse, 135, av. de Rangueil, F-31077 Toulouse, France.

7 Ins. de Química Avanzada de Cataluña (IQAC), CSIC, Jordi Girona, 18-26, 08034, Barcelona, Spain.

8 Centro de Investigación del Cáncer (CIC), CSIC-Univ. of Salamanca, 37007 Salamanca, Spain.

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After a period of intense research, nanoparticles incorporating a biological functionality have already found several punctual applications in biotechnological and clinical practices. Nowadays, the development of functionalization techniques with a high versatility permits to aspire to a more general use of nanoparticles in nanomedicine. In this direction, the concept behind this work pretends to use nanoparticles as a platform for assembling multiple interchangeable pieces each of them incorporating a physical or biological functionality. The nanoplatform presented here shows that it is possible to combine physical, chemical and biological functionalities in a single particle and simultaneously. It consists on a hydrophobic polymer core having a surface with multiple equal anchoring groups for the covalent bonding of the functionalised pieces. This core in itself may also incorporate several functionalities in the form of smaller inorganic nanoparticles. The functionalised pieces consists of hydrophilic chains ending on a reactive group that fits on the core surface and holds at the other end a biological or physical functionality. The coupling system is a Michael addition from a Michael-donor (amine, thiol, etc) to a Michael acceptor (acrylate) [1]. This system has the advantages of a clean synthesis (no by-products), mild conditions, and an easy and controlled multifunctionalization.

The nanoplatform has been functionalized with radiochemical tracers (In111), luminescent dyes (fluorescein, rhodamine, lanthanide compounds), and magnetic nanoparticles, and therefore it can be a powerful tool in imaging. Besides, it has also been functionalized with a therapeutic drug, an antibody, and an optical thermometer made of lanthanide complexes [2]. Health safety of the system has been tested in cellular and in vivo assays. The nanoplatform is highly stable in

1

L.M.A. Ali1, R. Bustamante1 C. Brites2, L. Gabilondo1, J.L. Murillo1, N.J.O. Silva2 V. Sorribas3, M. Gutierrez4 R. Cornudella4, L. Carlos2, F. Palacio1, A. Lascialfiari5 J. Carrey6, M. Respaud6 G. C. Sanmartí7, J.-P. Salvador7 M.-P. Marco7, J. Criado8 M. Fuentes8 and A. Millan1

pinol@unizar.es amillan@unizar.es palacio@unizar.es

biological fluids, shows low cell toxicity [3], high capacity of cell internalization, no in vivo damage for tissues and organs, excellent hematocompatibility, and anticoagulation properties [4]. It is shown that magnetic properties can be tuned up in the whole superparamagnetic range [5]. Moreover, the system has shown excellent performance in magnetic resonance imaging [6] and hyperthermia

References [1] R. Piñol, A. Millán, F. Palacio, L. Gabilondo,

[2]

[3]

[4]

[5]

[6]

Spanish Patent no. P201031493 submitted to the Spanish Patent and Trademark Office (0710-2010).

C. D. S. Brites, P. P. Lima, N. J. O. Silva, A. Millán, V. S. Amaral, F. Palacio, L. D. Carlos, Advanced Materials, 22 (2010) 4499-4504.

R.Villa-Bellosta, G. Ibarz, A. Millan, R. Piñol, A. Ferrer-Dufol, F. Palacio, V. Sorribas, Toxicology Letters, 180, (2008) S221-S2216.

Lamiaa M.A. Ali, M. Gutiérrez, R. Cornudella, J.A. Moreno, R. Piñol, L. Gabilondo, A. Millán and F. Palacio, J. Biomed. Nanotechn. (in press) (2013).

A. Millan, F. Palacio, A. Falqui, E. Snoeck, V. Serin, A. Bhattacharjee, V. Ksenofontov, P. Gütlich and I. Gilbert, Acta Materialia, 55, (2007), 2201-2209.

H. Amiri, P. Arosio, M. Corti, A. Lascialfari, R. Bustamante, A. Millán, N.J.O. Silva and F. Palacio, Magn. Res. in Medicine, 66, (2011) 1715-1721.

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Figures

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Figure 1: Hydrophobic polymer Fluorescent probe Magnetic core (ÎłFe2O3) Hydrophilic polymer (PEG) Hydrophilic polymer with anchoring groups (PEG) Antibody Scheme of core-shell multifunctional nanoplatform containing magnetic nanoparticles.

Oral Nanoparticles of plant origin exploited for multiple applications

Fernando Ponz F. Sรกnchez, C. Mansilla P. Ibort, S. Cuenca M. Aguado, C. Cruz and I. Gonzรกlez.

CBGP (UPM-INIA). Montegancedo, Pozuelo, Madrid, Spain

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Plant-made viral nanoparticles (VNPs) are natural nano-objects with the characteristics of typical nanoparticles such as size, monodispersity and symmetry, which can be exploited as scaffolds for building modified nanostructures with multiple applications. In addition, plant VNPs are produced at a rather low cost; being composed of proteins they are completely biocompatible; and they do not have the ability to infect animals or humans, thus offering an extremely high degree of biosafety.

(VNPs) can take several forms, which mainly fall into two biological categories. Either the particles enclose and pack a nucleic acid (virions) or they do not (virus-like particles, VLPs). Each of them has its particular pros and cons for nanotechnological deployment. The modifications performed on VNPs also can be achieved by two main approaches: genetic or chemical modifications.

Using combinations of these possibilities we are currently developing VNPs derived from Turnip mosaic virus (TuMV) as a nanoplatform for several applications.

Each TuMV VNP is a flexuous nanorod with a diameter of ca. 15nm, made up of over 2000 identical protein subunits helically arrayed (Figure 1). This structure can be conveniently modified for different purposes depending on the particular application sought. We will be presenting and discussing our progress in the exploitation of TuMV VNPs as scaffolds for peptide and protein presentation. These modifications have allowed us to develop applications in the areas of enhanced immunization and antibody production, sensitive detection of antibodies and infectious agents, and enzyme nanoimmobilization for improved industrial biocatalysis.

Figures

Figure 1: Electron micrograph of purified TuMV VNPs, showing their structural characteristics of flexuous nanorods.

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Víctor Puntes J. Comenge, C. Sotelo F. Romero, O. Gallego A. Barnadas T. García-Caballero and F. Domíngue

Institut Català Nanotecnologia, Universidad Santiago de Compostela, Universidad de Lugo, Hospital de Sant Pau, Spain

victor.puntes@ic.cat

Last decade has seen a flourishment in the study of the properties of inogranic nanoparticles for medical applications. Nanoparticles display properties that are strongly determined by both morphology and environment and in the physicochemical context where they are immersed, therefore allowing to monitor and manipulate biological states. In fact, inorganic nanoparticles behave as "artificial atoms", since their high density of electronic states -which controls many physical properties- can be extensively and easily tuned by adjusting composition, size and shape and used in biological environments. In fact, nanotechnology’s ability to shape matter on the scale of molecules is opening the door to a new generation of diagnostics, imaging agents, and drugs for detecting and treating disease at its earliest stages. But perhaps more important, it is enabling researchers to combine a series of advances, creating thus nanosized particles that may contain drugs designed to kill tumours together with targeting compounds designed to home-in on malignancies, and imaging agents designed to light up even the earliest stage of cancers. In fact, a description of cancer in molecular terms seems increasingly likely to improve the ways in which human cancers are detected, classified, monitored, and (especially) treated, and for that, nanoparticles, which are small and therefore allows to address molecular structures in an unique manner, may be specially useful for those tasks.

Thus, Nanoparticles (NPs) have emerged as a potential tool to improve cancer treatment.

Among the proposed uses in imaging and therapy, their use as a drug delivery scaffold has been extensively highlighted. However, there are still some controversial points which need a deeper

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understanding before clinical application can occur. Here the use of gold nanoparticles (AuNPs) to detoxify the antitumoral agent cisplatin, linked to a nanoparticle via a pH-sensitive coordination bond for endosomal release, is presented. The NP conjugate design has important effects on pharmacokinetics, conjugate evolution and biodistribution and results in an absence of observed toxicity. Besides, AuNPs present unique opportunities as drug delivery scaffolds due to their size and surface tunability. Here we show that cisplatin-induced toxicity is clearly reduced without affecting the therapeutic benefits in mice models. The NPs not only act as carriers, but also protect the drug from deactivation by plasma proteins until conjugates are internalized in cells and cisplatin is released. Additionally, the possibility to track the drug (Pt) and vehicle (Au) separately as a function of organ and time enables a better understanding of how nanocarriers are processed by the organism.

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Detoxifying Antitumoral Drugs via Nanoconjugation: The Case of Gold Nanoparticles and Cisplatin

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Invited

Oral Nanofluidic system for matrix-free DNA analysis

Hubert Ranchon 2 J. Lacroix 1 C. BlatchĂŠ and A. Bancaud1

1

1

CNRS, LAAS; 7 avenue du colonel Roche, F-31400 Toulouse, FRANCE Univ de Toulouse, LAAS, F-31400 Toulouse, France

hranchon@laas.fr

2

354

Chromosomes are the universal support of the genomic material, and their analysis at the genome level is among the most active field of research and innovation. Most analytical tools have the ability to sequence short DNA fragments, which are subsequently registered by computers to define a complete genome. This cost-ineffective situation is mostly related to the history of molecular biology techniques, which have been developed to characterize DNA chains of less than ~20 kbp. We posit that micro- and nanotechnologies offer new solutions to manipulate long DNA fragments, and hold great promise to the analysis of large scale genomic rearrangements which are common in cancer [1].

In this report, we describe a novel technology to separate biomolecules by size, which does not require the use of a separation matrix. The system consists of a silicon fluidic chip obtained by conventional photolithography, followed by dry etching (Fig.1.a). The slit-like geometry enables to monitor the environment of biomolecules, and we use a combination of hydrodynamic and electrophoretic to convey biomolecules (Fig.1.b), so that three control parameters, namely the geometry, the pressure, and the electric field, enable to control the progression of biomolecules in the channels. The application of an hydrodynamic field alone does not induce separation, whereas the application of an electric field acting opposite to the hydrodynamic flow improves the performances of our system: the chromatogram obtained with 500 mbar and 30 V shows sharp peaks for ten DNA species spanning 500 to 10000 bp in less than 8 minutes (Fig. 2).

Small DNA molecules migrate faster than large ones, as observed with conventional gel electrophoresis but not with hydrodynamic

separations [2]. Using real time single molecule nanoscale imaging, we show that size-dependent migration is achieved through transverse displacements: molecules accumulate along streamlines according to their molecular weight, so that their progression along channels is determined by their size. This phenomenon is enhanced with the geometry of the channel and with the rheological properties of the fluid, and we show the successful separation of DNA molecules from 100 bp to 100000 bp in minutes, a performance inaccessible to most technologies available on the market. Most importantly we demonstrate sharp variations of DNA velocity as a function of its size characterized by power-law scalings up to ~-2,75 (Fig. 3), thus outperforming conventional electrophoresis that is associated to a power-law scaling of -1 [3].

Overall this study is a demonstration of the potential of fluidic technologies for the life sciences. Our technology is readily adapted for integration in Lab-on-Chip applications, and it is well-suited to perform analytical operations on whole-chromosomes for novel biodiagnostic applications.

References [1] Stephens P.J. et al., Cell, 144 (2011) 27-40.

[2] Liu K.J et al., Journal of the American Chemical Society, 133 (2011) 6898-6901.

[3] Viovy J.L., Review of Modern Physics, 72

(2000) 813-872.

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Figures Buffer tanks RĂŠservoirs (solvant)

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Figure 3: Velocity of DNA molecules as function of their lengths. kb ladder (left). 100 bp ladder (right). Pressure drops and voltages are indicated in inset. Tuning of the electric field and pressure drop induces sharp variations in mobility with the molecular weight. The highest variations are associated to a power scaling of ~ -1.33 and ~ -2.75 (black dashed and dotted lines).

Oral Towards DNA-Coated Anisotropic Building-Blocks: A Robust Surface Modification Strategy to Functionalize Gold Nanorods with DNA Oligonucleotides

Jessica Rodríguez-Fernández V. Baumann and F. Haase

Jessica.Rodriguez@lmu.de

Ludwig-Maximilians-Universität (LMU), Amalienstr. 54, Munich, Germany

Anisotropic nanoparticles like gold nanorods (Au NRs) are appealing building-blocks for the development of higher-order assemblies with strong plasmon-plasmon interactions and thus, sensing potential. DNA-directed assembly is one of the most powerful and versatile strategies to controllably direct either the self-organization of colloidal nanoparticles [1] or the formation of biocompatible organic-inorganic nanoscale hybrids of complex geometries.[2] In this context, the effective functionalization of Au NRs with DNA is a necessary key step, where the challenge remains in avoiding NR aggregation throughout the DNAmodification process.

In this work we have developed a strategy to functionalize CTAB-stabilized gold nanorods with DNA oligonucleotides while maintaining their colloidal stability.[3] Our approach consists of a ligand exchange process that leads to the careful displacement of CTAB from the Au surface by “thiolated” helper molecules first and by thiolated DNA strands in the last instance. We will present our results on the optimization of the different surface functionalization steps and on the quantification of DNA grafting on the Au NRs’ surface. We will also show that the asfunctionalized nanorods are highly stable overtime in high ionic strength media. Taken altogether, our results indicate that our DNA-functionalized Au NRs may be used as building-blocks for DNAdirected (self)-organization.

[2] J. K. Do, R. Schreiber., A. A. Lutich, T. Liedl, J.

Rodríguez-Fernández, J. Feldmann, Nano Letters, 12 (2012), 5008.

[3] V. Baumann, F. Haase, J. Rodríguez-Fernández, in preparation.

References

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[1] C. A. Mirkin, R. L. Letsinger, R. C. Mucic, J. J. Storhoff, Nature, 382 (1996), 607.

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Oral Transformation and toxicity of PAMAM dendrimers under irradiation and ozonation processes

1,2

Roberto Rosal 2 J. Santiago-Morales 3 M. D. Hernando M. M. Ulaszewska1 1 E. García-Calvo and 1 A. R. Fernández-Alba

1

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corona discharge and continuously bubbled as described elsewhere [7]. Irradiation experiments were carried out using a 15W Heraeus Noblelight TNN 15/32 low-pressure mercury vapour lamp emitting at 254 nm and a Heraeus TQ Xe 150 Xearc lamp with spectral emission in the visible region. The temperature was 25°C and pH was controlled at 7.0 ± 0.1 units. Samples were withdrawn for analysis at prescribed intervals.

Analytical. The analyses have been performed by liquid chromatography using a hybrid quadrupole/time of flight mass analyzer (LC-ESIQTOF-MS) and a TripleTOF 5600 System (AB SCIEX, Concord, ON) coupled to an HPLC Agilent 1200 (Agilent Technologies, Wilmington, DE, USA) with a ESI source. The AB SCIEX TripleTOF 5600 equipment offers the capability of high resolution detection with resolving power 40000 (FWHM).

The LC analyses were performed with a reversedphase C5 analytical column 150 mm length x 4.6 mm I.D. and 5 µm particle size. The MS was operated in full scan TOF-MS and MS/MS mode through information dependent acquisition (IDA) in a single run analysis. The data acquisition and processing was carried out using Analyst® TF 1.5 and PeakViewTM. Toxicity. The toxicity of samples corresponding to partially oxidized and irradiated mixtures was assessed using the following bioassays: multigenerational growth inhibition of the green alga Pseudokirchneriella subcapitata (OECD TG 201), the inhibition of the constitutive luminescence of the marine bacterium Vibrio fischeri (ISO 11348-3 standard protocol), the 48 h immobilization of the microcrustacean Daphnia magna (OECD TG 202 performed with the commercially available text kit Daphtoxkit F™ magna, Creasel, Belgium) and the phytotoxicity

NANOBIO&MED 2013

Dendrimers are a class of thoroughly branched polymers characterized by a high chemical versatility. Dendrimers have unique properties such as uniform size, well-defined molecular weight and tunable surface functionality and solubility. Also, the presence of rather large internal cavities makes them interesting for many biological and medical applications [1, 2]. The cytotoxic properties of dendrimers including the influence of surface modification have been the subject of recent scientific publications [3, 4]. Most of the available data found connections between cytotoxicity surface charge and dendrimer generation, which determine cell permeability. In general, cationic PAMAM dendrimers have been associated with higher cytotoxicity than anionic or neutral dendrimers. Also, growing dendrimer generation has been associated with increased toxicity [5]. After therapeutic use dendrimers are excreted. For example, Nigavekar et al. reported that neutral PAMAM G5 dendrimer-based organic nanoparticles resulted in a higher urinary excretion (and lower via faeces) than those bearing positive charge [6]. Once released, the dendrimers would undergo oxidation and photolytic transformation processes, either in water treatment plants or under the action of natural processes. This may lead to the production of secondary pollutants which occurrence and toxicity also needs to be addressed. The goal of this work is to identify and to assess the toxicity of the transformation products of G3-PAMAM-(NH2)32 dendrimer during irradiation and oxidative degradation.

Oxidation and irradiation procedures. PAMAM dendrimer G3-PAMAM-(NH2)32 was purchased from Dendritech. The solutions were prepared in pure water (Milipore Mili-Q) with a resistivity of at least 18 Mcm-1 at 25 ºC. Ozone was produced by

roberto.rosal@uah.es

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Advanced Study Institute of Madrid, IMDEA-Agua, Parque Científico Tecnológico, Madrid, Spain 2 Department of Chemical Engineering, University of Alcalá, Alcalá de Henares, Madrid, Spain 3 Department of Environment, Spanish National Institute for Agricultural and Food Research and Technology (INIA), Madrid, Spain

based on seed germination tests following US EPA procedures on Licopersicon esculentum, Lactuca sativa and Lolium perenne [8]. The assessment of reactive oxygen species (ROS) generation was performed by loading cultures of control and treated cells with the fluorescents dyes 2,7dichlorofluorescein diacetate (H2DCFDA) and C4BODIPY, the first serving as indicator for hydrogen peroxide and other ROS, such as hydroxyl and peroxyl radicals and the later being used for evaluating lipid peroxidation. Dichlorofluorescein (DCF), chlorophyll and C4-BODIPY fluorescence was visualised using confocal fluorescence microscopy (Leica TCS SP5).

The analytical method developed with LC-ESIQTOF-MS has allowed the identification of the dendrimer G3-PAMAM-(NH2)32 and the structural elucidation of the transformation products generated in the oxidation and irradiation processes. The multiple-charging phenomenon of G3-PAMAM-(NH2)32, associated with ESI, makes it possible the formation of multiply charged ions and provided key advantages in dendrimer identification by assignation of charge state through high resolution of 13C/12C isotopic clusters as well as a mass accuracy below 3.8 ppm for the diagnostic ions. The structures of relevant TP have been elucidated based on mass accuracy, in both full scan and MS/MS modes via IDA, and elemental composition assignation. Fig 1 (left) shows the LCESI-QTOF-MS mass spectrum in full scan mode for G3-PAMAM-(NH2)32. G3 was characterized by a charge state distribution up to +10, 13C/12C isotopic resolution (peak-spacing and isotopic distribution).

This figure also presents an overlay of the TIC (total ion chromatograms) with the gradual formation of two relevant transformation products corresponding to the treatment with O3 after 130 min.

[4] Ulaszewska MM, Hernando MD, Uclés A, Rosal

[5] [6]

[7]

[8]

R, Rodríguez A, García-Calvo E, Fernández-Alba AR. Chemical and ecotoxicological assessment of dendrimers in the aquatic environment, in Marinella Farré y Damià Barceló (Eds.) Analysis and Risk of Nanomaterials in Environmental and Food Samples, Comprehensive Analytical Chemistry Volume 59, Chapter 6, 197-233, Elsevier 2012.

Naha PC, Davoren M, Casey A, Byrne HJ. Environ. Sci. Technol. 43 (2009) 6864–6869.

Nigavekar SS, Sung LY, Llanes M, El-Jawahri A,.

Lawrence TS, Becker CW, Balogh L, Khan MK. Pharm. Res., 21 (2004) 476-483.

Rosal R, Rodríguez A, Gonzalo MS, GarcíaCalvo E. Appl. Catal. B: Environ. 84 (2008) 48– 57.

US EPA. Ecological Effects Test Guidelines.

OPPTS 850.4200; Seed Germination/Root Elongation toxicity Test. US Environmental Protection Agency, Washington, DC. EPA712C-96-154 (1996).

Figures

Figure 1: LEFT: LC-ESI-QTOF-MS mass spectrum in full scan mode for G3-PAMAM-(NH2)32 and TIC chromatograms showing the formation of oxidation products. RIGHT: Confocal microscopy images of P. subcapitata exposed to 0.5 mg/L G3NH2 PAMAM during 72 h showing intracellular green BODIPY fluorescence as a result lipid peroxidation. Red fluorescence: chlorophyll autofluorescence. Bottom: overlay image of chlorophyll red autofluorescence and BODIPY green fluorescence and bright field image of the same preparation.

References [1] Suárez IJ, Rosal R, Rodríguez A, Uclés A,

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Fernández-Alba AR, Hernando MD, GarcíaCalvo E. TrAC Trend. Anal. Chem., 30 (2011) 492-506.

[2] Majoros IJ, Baker JR. (2008) Dendrimer-Based Nanomedicine, Pan Stanford Publishing, Singapore, 2008.

[3] Menjoge AR, Kannan RM, Tomalia DA. Drug Discov. Today 15 (2010) 171–185.

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Oral Versatile Bionanostructured Materials via Direct Reaction of Functionalized Catechols

Daniel Ruiz-Molina 1 J. Saiz-Poseu 2 B. García J. Sedó1 3 J. Hernando and 3 F. Busqué

1

1

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diameter in water, which easily stick to polyester fibers affording stable NP coatings. Even though synthetic polydopamine nanoparticles resembling eumelanin particles that constitute sepia ink have already been described in the literature, to our knowledge this is the first example where chemically-related NPs have been reported to exhibit adhesive properties. On the other side, when this material is dissolved in non-polar solvents such as hexane, robust coatings on a representative variety of substrates, both at the nano-/macroscale are obtained, by means of a quick and ex situ approach without any pretreatment or modification. Whereas catechol monomers bearing a long alkyl chain afford coatings with a persistent hydrophobic character, it was shown that this methodology can be extended to several other catechols with different ring pendant groups, providing varied surface functionalities such as oleophobic/hydrophilic, anti-fouling, anti-bacterial activities and water remediation.

Conclusion A new methodology for the fabrication of bionspired catechol-based nanoparticles and coatings is reported. The chemical versatility of the approach allows for a broad range of functionalities that can be added, opening new paths in the realization functional and bioactive materials, an ever growing field of interest.

Acknowledgments: This work was supported by MICINN through projects MAT2012-38318-C03-02, MAT2012-38319-C02-01, CTQ2010-15380 and CTQ2009-07469. We are also grateful to Generalitat de Catalunya for project 2010VALOR00039.

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Mussel-adhesive proteins have been the subject of intensive scientific research associated to their remarkable ability to strongly adhere to virtually all surfaces. Albeit diverse in structure, this behavior has been attributed to their varying amounts of the non-essential catecholic aminoacid DOPA. Since this discovery, an ever-increasing number of bioinspired catechol-based polymers have been used for the fabrication of water-resistant adhesives, protective layers, primers for functional adlayers and nanoscale coatings, among others.1 Herein we report a new approach for the preparation of catechol-based materials based on a simple polymerization process in the presence of ammonia,2 in a way reminiscent of melanization reactions. This strategy represents a significant advance in combining many advantages of methods reported previously: ease of preparation, solubility in appropriate solvents and a high ratio of adhesive (catecholic)-to-functional moieties.

Experimental methods In a typical experiment, a large molar excess of aqueous ammonia was slowly added under vigorous stirring in the presence of air to a solution of the corresponding monomer (0.2 % , w/v) in methanol, at 40 ºC. Thin-layer chromatography (TLC) was used to follow the reaction, showing that the majority of monomer had already reacted after 3 hours, and consumed quantitatively within 24 hours, after which a dark-brown amorphous solid could be extracted with chloroform and isolated by evaporation.

Results and discussion As a proof of concept, the first molecule of choice was a catechol bearing a long alkyl chain. The material resulting from its reaction with ammonia is shown to spontaneously structure in the form of nanoparticles a few hundred nanometers in

druiz@cin2.es

NANOBIO&MED 2013

Centro de Investigación en Nanociencia y Nanotecnología, Campus UAB, 08193, Cerdanyola del Valles,Spain 2 Fundación Privada ASCAMM, Unidad de Nanotecnología (NANOMM), ParcTecnològic del Vallès, Av. UniversitatAutònoma, 23 - 08290 Cerdanyola del Vallès, Spain 3 Chemistry Department, Universitat Autònoma de Barcelona, Campus UAB 08193, Cerdanyola del Vallès, Spain

References [1] Ruiz-Molina et al. et col. Adv. Mat. 2013 DOI: 10.1002/ adma. 201202343.

[2] Ruiz-Molina et al. Adv. Mat. 2013 In press.

[3] Ruiz-Molina et al. Adv. Funct. Mat. Submitted.

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Figure 1: Left: (a) Molecular structure of the building block. (b) TEM and (c) SEM images of the polymerization product. (d) Fluorescence emission spectrum of the polymer in aqueous solution (位exc=355 nm, 位det>400 nm) and (inset) fluorescence microscopy image of 2NPs deposited onto glass (位exc=540-552 nm). Right: (a) Schematic representation of the process carried out for coating the substrates with compound 2. (b) TEM images of MWCNT coated with the polymer after being dispersed in a 0.5% (w/v) n-hexane solution for 30 minutes. The green arrows mark the MWCNT wall; the orange arrows point at the coating thickness. (c) Different behavior of blank and treated MWCNT dispersed in water and ethyl acetate.

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Oral Recent therapeutic advances using polystyrene microspheres as delivery systems

Rosario M. Sánchez-Martín

rmsanchez@ugr.es rosario.sanchez@genyo.es

University of Granada, Deparment of Medicinal and Organic Chemistry, Faculty of Pharmacy, Campus Cartuja, s/n, 18071, Granada, Spain GENYO. Centre for Genomics and Oncological Research: Pfizer / University of Granada / Andalusian Regional Government, Av. de la Ilustración, 114 – PTS, 18016, Granada, Spain

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References

N.; How, S.E.; Mittoo, S.; Bradley, M., ChemBioChem, 6 (2005) 1341-1345.

[2] Unciti-Broceta, A.; Johansson, E. M.V.; Yusop, M.; Sánchez-Martín, R. M.; Bradley. M., Nature Protocols, 7 (2012) 1207–1218.

[3] Sánchez-Martín, R. M., * Alexander, L.; Cardenas-Maestre, J.M.; Bradley, M., Strategies for Microsphere-Mediated Cellular Delivery, Book: Ideas in Chemistry and Molecular Sciences: Where Chemistry meets Life, Wiley-VCH Ed. Pignataro, B. (2010) 117– 140.

[4] Sanchez-Martin, R.M.; Cuttle, M.; Mittoo, S.; Bradley, M. Angew. Chem. Int. Ed., 45 (2006) 5472 - 5474.

[5] Sanchez-Martin, R. M.*; Alexander, L.; Muzerelle, M.; Cardenas-Maestre, J. M. ; Tsakiridis, A.; Brickman, J. M.; Bradley, M. ChemBioChem, 10 (2009) 1453-1456.

[6] Tsakiridis, A.; Alexander, L.; Gennet, N.; Sanchez-Martin, R. M.; Livigni, A.; Li, M.; Bradley, M.; Brickman, J. M., Biomaterials, 30 (2009) 5853-5861.

[7] Alexander, L.; Sanchez-Martin, R. M.; Bradley, M. Bioconjugate Chem, 20 (2009) 422-426.

[8] Borger, J.G.; Cardenas-Maestre, J.M.; Zamoyska, R.; Sanchez-Martin, R.M.* Bioconjugate Chem,22 (2011) 1904-1908.

[9] Cardenas-Maestre, J.M.; Panadero-Fajardo, S.; Perez-Lopez, A.M.; Sanchez-Martin, R.M.* J. Mater. Chem., 21 (2011) 12735-12743.

[10] Unciti-Broceta, A.; Díaz-Mochón, J. J.; SánchezMartín, R. M.* and Bradley, M.* Accounts Chem. Res., 45(7) (2012) 1140-1152.

[11] Dhaliwal, K.; Alexander, L.; Escher, G.; UncitiBroceta, A.; Jansena, M.; Mcdonalda, N.;

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[1] Sanchez-Martin, R.M.; Muzerelle, M.; Chitkul,

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The search for efficient and safe carrier systems to achieve better availability of therapeutic cargoes at the target site has been a challenging yet exciting area of research. Nowadays many research teams are focused in the development of approaches based in the use of nanodevices as tool to achieve novel therapeutic strategies.

We have developed a simple technique for the synthesis of a range of robust and biocompatible functionalized polymer microspheres of highly defined size (100 nm – 500 nm) and loading (Figure 1). [1-2] A range of bioactive cargoes have been conjugated to these particles following a multifunctional strategy and they have been effectively taken up by different type of cells included primary cells and embryonic, neuronal and mesenchymal stem cells (Figure 2).[3] We have demonstrated that these microspheres can efficiently deliver various small molecules (e.g. biosensors) and macromolecules (e.g. proteins).[45] We also show that microsphere internalization does not affect ES cell pluripotency as beadtreated ES cells could be used to generate high contribution chimeric embryos.[6] We have developed several chemical strategies to use these devices as transfection agents (delivery of oligonucleotides such as pDNA and siRNA).[7-10] These devices have been for in vivo cell tracking.[11] Recently we have successfully developed micro heterogeneous catalysts by immobilising palladium nanoparticles on these microspheres and employed them to do chemistry in living systems.[12] These microspheres are inherently attractive as a delivery system due to their lack of toxicity and highly controllable cellular loading.

Cardenas-Maestre, J.M.; Sanchez-Martin, R.; Simpson, J.; Hasletta, C.; Bradley, M. Faraday Discuss., 149 (2011) 107-114.

[12] Yusop, M.; Unciti-Broceta, A.; Johansson, E. M.V.; SĂĄnchez-MartĂ­n, R. M.; Bradley. M. Nature Chemistry, 3 (2011) 239-243.

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Figure 1: SEM images of cross linked microspheres.

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Figure 2: Microspheremediated delivery in differentiating Embryonic Stem (ES) cells. Confocal microscopy images of day 7 EBs derived from aEGFP cells.

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Oral Stimuli-Responsive DNA- Nanovalves for Controlled Delivery and Nanodevices

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stimulus such as temperature or pH. These interfaces were incorporated both into mesoporous structures as well as nanoporous membranes [1,2] and upon contacting with the target molecule, they were supposed to cause a change in membrane permeability owing to the significant conformational change of the aptamer receptor molecules. This work will highlight both the capacity of DNA-aptamers for triggering permeability or controlled release, as well as the characterization techniques employed for elucidating and verifying their function and dimensions of the respective conformational changes [3].

Methods: The surface of nanoporous alumina membranes and mesoporous particles was adequately modified for the immobilization of an ATP-aptamer (receptor) as well its unselective mutated form as a negative control. Flouresceine was then used as a tracer molecule in an adjacent feed solution and its permeation across the modified nanoporous membranes monitored as a function of the presence of ATP (target) in the feed. For characterizing the ATP-aptamer responsive membranes, characterization techniques such as quartz crystal microbalance with dissipation monitoring (QCM-D), surface Plasmon resonance (SPR) and dual polarization interferometry (DPI) were employed. The latter proved particularly useful in case where changes were only in the sub-nm range. With regard to the receptor molecules, we opted for an ATP-binding aptamer because ATP with a molar mass of 507,18 g•mol−1 may still be considered a small molecule, and as such posed a challenge to serve as a trigger for conformational changes that would be sufficient to reversibly change the permeability of the overall membrane barrier.

NANOBIO&MED 2013

Approaches to creating stimulus-responsive membranes have been explored for decades for liquid separations or controlled release applications yielding materials whose permeability varies, triggered by a change of pH, temperature, or ionic strength of the adjacent liquid, or the exposure to light, an electrical or a magnetic field.

It remains a challenge, however, to mimic the specific and locally acting molecular recognition mechanism found in Nature for triggering a change of permeability in cell membranes, where a specific target-receptor interaction triggers a conformational change of a membrane transporter protein resulting in turn in a variation of the effective diameter of the cell membrane pores.

While the incorporation of such transporter proteins is one route to creating artificial molecular stimuliresponsive membranes, a possibly more robust and simpler one is the surface modification of a porous membrane structure with simpler molecules but likewise capable of recognition of a molecular stimulus, such as DNA-aptamers. The capacity of DNAaptamers to reversibly and specifically bind to target molecules of virtually any molecular size while undergoing a conformational change is being explored since very recently for the surface modification of nanoparticless or biosensors1. The challenge for membrane barriers, however, has remained in the application of their molecular recognition principle on a larger substrate area, and most of all to achieve reversibility in its conformational changes for repeated applications.

We here report on the performance of selfassembled stimuli-responsive interfaces based on DNAaptamers which respond upon a molecular recognition of a relatively small molecule, adenosinetriphosphate (ATP) rather than a bulk

thomas.schafer@ehu.es

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POLYMAT, University of the Basque Country, Av. Tolosa 72, Donostia-San Sebastián, Spain

Thomas Scháfer V.C. Özalp A. Pinto F.J. Hernadez L. Hernandez and A. Pinto

Results: The self-assembled stimuli-responsive membrane barrier, with its concept depicted in Figure 1, as well as mesoporous particles based on aptamers were capable of reversibly changing their permeability or controlled release upon the molecular recognition of ATP, rather than respond to a bulk stimulus.

Negative controls using both mutated aptamers or GTP as a target rather than ATP did not show any significant response of the membrane, whatsoever, proving that the concept proposed did actually rely on a highly selective molecular recognition mechanism as is hitherto mainly known from biological membranes. When the system proposed was furthermore tested under varying medium compositions, such as the presence of serum in order to simulate physiological conditions, no deterioration of the stimuli-responsiveness was observed. The proofof-concept of our membrane design is particularly promising as aptamers as acting receptor molecules can be selected toward virtually any kind of target, ranging from small molecules to proteins and even cells. We will show how we have also successfully applied this modular approach for nanoparticles targeting cancer cells [4], proving that the approach taken addresses a wide range of possible applications in biomedicine or bioseparations in general.

Figures

Figure 1: Schematic of the gate-keeper membranes developed. In absence of the target (ATP), fluoresceine freely permeates the nanoporous membrane; in presence of the target, ATP, the NAaptamer undergoes a drastic conformational change causing a relatice blocking of the pore.

References [1] Özalp, V.C., and Schäfer , T. Chem. Eur. J., 17(36), 9893–9896, 2011.

[2] Schäfer, T., Özalp, V. C. in: Responsive

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Membranes and Materials, Eds. D. Bhattacharyya, R. Ranil Wickramasinghe, Sylvia Daunert, Thomas Schäfer, John Wiley & Sons, 2012.

[3] Serrano-Santos, M.B., Llobet, E., Özalp, V.C and Schäfer, T. Chem. Commun., 2012, 48, 10087 - 10089 (cover story).

[4] Hernandez, F.J., Hernandez, L.I., Pinto, A., Schäfer, T. and Özalp, V.C., Chem. Commun., 2013,49, 1285-1287.

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Invited SERS Microscopy: Tissue Diagnostics with Rationally Designed Nanoparticle Probes

Sebastian Schlücker M. Salehi and M. Schütz

sebastian.schluecker@uni-due.de University of Duisburg-Essen, Physical Chemistry, D-45141 Essen, Germany

References

[2] S. Schlücker, B. Küstner, A. Punge, A. Marx, P.

[3] [4]

[5]

[6] [7]

Ströbel, J. Raman Spectrosc. 37 (2006) 719721.

Y. Wang, S. Schlücker, Analyst. 138 (2013) 2224-2238.

C. Jehn, B. Küstner, P. Adam, A. Marx, P. Ströbel, C. Schmuck, S. Schlücker, PCCP 11 (2009) 7499-7504.

B. Küstner, M. Gellner, M. Schütz, F. Schöppler, A. Marx, P. Ströbel, P. Adam, C. Schmuck, S. Schlücker, Angew. Chem. Int. Ed. 48 (2009) 1950-1953.

M. Schütz, B. Küstner, M. Bauer, C. Schmuck, S. Schlücker, Small 6 (2010) 733-737.

M. Salehi, D. Steinigeweg, P. Ströbel, A. Marx, J. Packeisen, S. Schlücker, J. Biophoton. (2013), DOI: 10.1002/jbio.201200148.

Figures

NANOBIO&MED 2013

Surface-enhanced Raman scattering microscopy (µSERS) [1] employs target-specific colloidal SERS probes in combination with Raman microspectroscopy. For example, SERS-labeled antibodies allow the selective and sensitive localization of the corresponding antigen in tissue specimens [2].

The physical and chemical properties of the colloidal SERS probes are crucial for the success of SERS microscopic experiments [3]. Stability and robustness, sensitivity as well as steric accessibility for bioconjugation are few very important aspects.

Figure 1 left shows a hydrophilic SERS probe stabilized by many short and few longer hydrophilic spacer units [4]. A second approach, based on the glass encapsulation for stabilizing SERS labels, is schematically depicted in Figure 1 right. This type of SERS probes was optimized for red laser excitation in order to improve image contrast by minimizing unwanted autofluorescence of biological specimens [5]. Two different routes to the glass encapsulation of a complete monolayer of Raman reporters will be described [5-6]. Small clusters (dimers, trimers) of gold nanocrystals even exhibit single-particle sensitivity and enable rapid mapping experiments with only 30 msec acquisition time per pixel [7].

Future directions of this innovative Raman/SERS microspectrosopic technique for tissue-based tumor diagnostics will be discussed.

Figure 1: (Left) SERS labels [3] stabilized by many short and few longer hydrophilic spacer molecules for controlled bioconjugation [4]. (Right) SERS nanoprobes optimized for red laser excitation for minimizing tissue autofluorescence. Gold/silver nanoshells are covered by a complete self-assembled monolayer (SAM) of Raman labels. The SERS particle is protected and stabilized by a glass shell [5-6].

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365

[1] S. Schlücker, ChemPhysChem 10 (2009) 13441354.

Oral Current research strategies for toxicity assessment of engineered nanomaterials. Lessons learned from European Projects

Blanca Suárez-Merino F. Goñi de Cerio C. Aristimuño and P. Heredia

suarezb@gaiker.es GAIKER Technology Center, Parque Tecnológico de Zamudio Ed. 202, 48170, Zamudio, Vizcaya, Spain

366

The rate at which novel nanomaterials are entering the marketplace and their unlimited economic potential is not being followed by updated regulation regarding the use of nanomaterials and their implications for human and environmental safety. The consequences of this gap of knowledge are at least two fold, on one hand consumer´s confidence is at stake, on the other there is a risk to lose an opportunity for innovation.

At present there are a large number of uncertainties regarding the use of traditional toxicology to evaluate the toxicity of nanomaterials, which, due to their special physical characteristics, require further assessment when considering the particular methodology to be used.

Furthermore, these new properties may be able to alter the absorption and transport capacity of nanoparticles across membranes. There is also a potential for nanoparticles to accumulate in organs, enter into blood circulation or even cross biological barriers.

In this context GAIKER-IK4 is involved in the development of novel methodologies to perform in vitro toxicological evaluation combining technologies such as flow cytometry, confocal microscopy and nanogenotoxicity to produce an in vitro tool-kit to accurately assess nanotoxicity. Our experience is based on our participation and leading roles in International Projects dealing with safety and efficacy assessment of nanomaterials from a Pharma, Cosmetic and Occupational Health point of view [1,2].

Our strategy aims at the core of engineered nanomaterial development, assisting in nanomaterial design by providing a fast and reliable evaluation of nanoparticle toxicity in the same fashion as any other conventional drugs are assessed for toxicity at their preclinical stage.

References [1] Serri R, Iorizzo M, Cosmeceuticals: focus on

topical retinoids in photoaging. Clin Dermatol 26 (6) (2008) 633-635.

[2] Halevy S Dead Sea bath salt for the treatment of psoriasis vulgaris: a double-blind controlled study. Journal of the European Academy of Dermatology and Venereology 9. (1997) 237242.

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Oral

2

College of Engineering, Swansea University, SA2 8PP Swansea, UK College of medicine, Swansea University, SA2 8PP Swansea, UK

Human chorionic gonadotropin (hCG), a 37 kDa glycoprotein hormone [1], is an important biomarker for pregnancy and one of the most important tumor markers for several cancers [2].

Most modern assay systems for hCG are optical based ELISAs. Though advances have been made in miniaturization of sensor diagnostics, in point of care detection, and even automated/continuous monitoring systems, the desired level of sensitivity for early detection and monitoring for cancer has not yet been achieved.

A novel chemically-modified graphene diagnostic sensor has been developed for ultrasensitive detection of a hCG (human chorionic gonadotropin) biomarker. Multi-layer epitaxial graphene (MEG), grown on silicon carbide substrates, has been patterned using electron beam lithography to produce channel based devices. Silicon Carbide (SiC) is a suitable substrate for graphene growth [3-7]. Graphene is grown by sublimating the silicon from the SiC substrate.

Graphene, essentially a single atomic layer of graphite, has some exceptional electronic properties such as carrier mobilities of more than 15000 cm2 V-1s-1 at room temperature and ballistic transport of carriers [4]. Modifying the growth conditions yields variations in the graphene layer thickness and consequently its electronic properties.

Diagnostics based on bio-functionalised semiconductor devices are an important development in ultrasensitive sensors for early detection and monitoring of disease biomarkers.

The chemical sensor uses chemically-modified graphene channels, functionalized with a “bioreceptor” antibody to detect the presence of the disease target biomarker, anti-hCG. It is then able to interact with the surface-bound bioreceptor and produce a change in the charge properties of the

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r.s.r.teixeira.607010@swansea.ac.uk

biosensor device. This surface charge modification is measured by amperometry on our graphenebased channel devices.

The attachment of the anti-hCG onto the graphene surface requires two parallel processes: the surface modification and the antibody modification.

The surface modification is performed by firstly terminating the graphene with -OH groups using the Fenton reaction [8], then reacted with 3Aminopropyl-triethoxysilane (APTES) [9] in order to obtain an amine-terminated surface. This is illustrated in Figure 1 (a to d) where the presence of the silane and the carbon chain from the Aptes molecule are clearly detected using XPS. Amine groups, along with oxygen in the C-O-Si configuration were also detected (Table 1).

In order to be able to react with the surface amine groups, the carboxylic acids on the antibody are activated. However, in order to prevent the antibody from cross-linking, the majority of amine groups on the antibody are blocked using Di-tertbutyl dicarbonate. The antibody can now be reacted with the amine on the surface. The groups blocking the amines on the antibody are subsequently removed by mild acidic treatment.

The sensitivity of the obtained device was then tested against varying concentration of hCG by measuring the resistance across the modified graphene channel (Figure 2). The obtained result showed a sensitivity of the sensor of 142 Ω/(ng/ml), and a detection limit around 1ng/ml.

References [1] J. Chen, J.H. Tang, et al. Biomaterials 27 (2006) 2313–2321.

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1

1

Sofia Teixeira 1 A. Castaing 1 G. Burwell R.S. Conlan2 and 1 O.J. Guy

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Graphene Biosensor for Detection of hCG Biomarker

[2] M. Aizawa, A. Morioka, et al. Anal. Biochem.

94 (1979) 22–28.

[3] O.J. Guy, M. Lodzinski, et al. Appl. Surf. Sci.,

Vol. 254, pp.8098-8105, 2008.

[4] C. Berger, Z. Song, et al. Science, Vol. 312, pp.1191-1196, 2006.

[5] A. Charrier, A. Coati, et al. J. Appl. Phys., Vol. 92,pp.2479-2484, 2002.

[6] C. Berger, Z. Song, et al. J. Phys. Chem. B, Vol. 108, pp.19912-19916,2004.

[7] A. Castaing, O.J. Guy, et al. Mater. Sci. Forum, Vols. 615-617, pp.223-226, 2009.

[8] R.H. Bradley, K. Cassity, et al. Applied Surface Science 258 (2012) 4835–4843.

[9] J. Kathi, K. Y. Rhee. J Mater Sci (2008) 43:33– 37.

Figure 1 (d): XPS core level spectrum of the C1s peak of a graphene sample after functionalisation (a) measured data, (b) fitted graphene peak(c) fitted SiC peak, (d), fitted APTES peak..

Figures

Figure 2: hCG concentration plotted as a function of channel resistance across a 100 μmx 4mm graphene channel.

Figure 1 (a): XPS core level spectrum of the Si2p peak of an epitaxial graphene sample (grown on SiC) before functionalisation (a) measured data, (b) fitted peak attributed to SiC.

Tabla: Description of bonds and atomic abundances calculated from the fitted components of the C, Si and N core peaks from XPS measurement before and after functionalisation with APTES.

Figure 1 (b): XPS core level spectrum of the Si2p peak of an epitaxial graphene sample after functionalisation (a) measured data, (b) fitted peak attributed to SiC and (c) fitted peak attributed to the silicon atom of the APTES molecule

368

Figure 1 (c): XPS core level spectrum of the C1s peak of a graphene sample before functionalisation (a) measured data, (b) fitted SiC peak and (c) fitted epitaxial graphene peak.

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Oral

Nano clays as sepiolite and clinoptilolite, have attracted increasing interest in biomedicine for their potential applications as nanovehicles.

However, no attempts have been made to evaluate the potential undesirable effects of sepiolite and clinoptilolite nanoparticles. The cytotoxicity of this two nano clays with different chemical structures was systematically evaluated in various macrophages types, such as human peripheral blood, mice bone marrow and cell line 264,7, by measuring cell viability and apoptotic pathway of death. In vivo evaluation was performed exposing CD1mice to suspensions of nano sepiolite and clinoptilolite at different concentrations (1, 2.5 and 5 mg/Kg of weight) by different ways (cutaneous, subcutaneous, intramuscular and intraperitoneal). No significant cytotoxic or toxic effects could be seen in both cases (in vitro and in vivo), but nano sepiolite was determined to be slightly more toxic than clinoptilolite in terms of cell viability and inflammation, this may be due to the differences in the structure. It is, therefore, expected that nano clays could be promising candidates for novel inorganic drug delivery carriers.

Introduction The origin of nanoscience and nanotechnologies is often attributed to a concept advanced by Nobel Laureate Richard P. Feynman, who in a 1959 lecture at the California Institute of Technology, stated: “There is plenty ofroom at the bottom. Many of the cells are very tiny, but they are active: they manufacture substance; they walk around; they wiggle: and they do all kinds ofmarvelous thingsall on a very small scale. Also they store information. Consider the possibility that we too can make things very small which does what we want when we want-and that we can manufacture an object that maneuvers at that

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yanistoledano@gmail.com

level”. [1] Nanoparticles are used in various fields such as photonics, catalysis, magnetics, and biotechnology including cosmetics, pharmaceutics, and medicines. In particular, research interest has focused on their potential as drug delivery nano vehicles and nano medicines [2,3] It is, therefore, needed to answer the questions on their safety issue by performing vigorous toxicological evaluation based on various models [4-7], and to understand their interaction mechanism as well.

Such a toxicological study can provide not only the critical information on the biological applications of nanoparticles, but also help to avoid any undesirable effects [8]. However, only a few studies have evaluated the safety of nano-sized materials and their potential adverse effects on biological systems [9].

Materials and methods. Parasite culture Entamoeba histolytica HM1-IMSS trophozoites were axenically grown in TYI-S33 medium supplemented with each nano clay so that the final concentrations were as follows: 1, 10, 50, and 100 mg/ml. Amoebic trophozoites viability was assessed employing two different methods, (1) vital marker trypan blue and (2) carboxyfluorescein diacetate (CFDA Vibrant kit) and propidium iodide done at 24, 28 and 72 hours under a microscope using a haemocytometer. Cellular assays Macrophages from human peripheral blood, for each experiment 1x105 cells per well were placed in 96 well-plate with 100μl of RPMI 1640 supplemented and enough nanoclay to reach 0.1, 1, 10 and 100mg/ml of medium in each well.

Apoptosis and necrosis were analysed each 12 hours for 48 hours by flow cytometry. In vivo tests CD1 mice were treated orally, cutaneously, subcutaneously, intramuscular and intraperitoneal with 1, 2.5 and 5mg of nano clay/Kg of weight and

NANOBIO&MED 2013

Universidad Nacional Autónoma de México, Circuito exterior s/n, Ciudad Universitaria, CP 04510 México D.F., México.

Yanis Toledano-Magaña L. Flores-Santos G. Montes de Oca-Ramírez A. González-Montiel and J. C. Carrero

369

Biocompatibility of nanoclays for future applications in biomedicine

analytes were measured for kidney and kiver function.

Results There is no significant effect in the cultures of Entamoeba histolytica treated with clinopiloite but the one that can be seen is dose and time dependent like for sepiolite but for this one the effect is significant for the higher concentrations (50 and 100mg/ml) it can be associated with the structure of the clays cause it is known that sepiolite is a fibrous clay until clinoptilolite have octahedric structure (Figure1). In the case of HPB (human peripheral blood) macrophages the effect is significant for the two clays at the higher concentrations (10, 100μg/ml) but is largest the percentage of cells affected with nano sepiolite (25%) than with nano clinoptilolite (20%) (Figure2).

For in vivo tests we observed the accumulation of nano clays without inflammation (Figure3), but orally the mice stomachs treated with nano sepiolite have a size reduction and black color in some areas (Figure4) however kidney and liver function are normal (Figure 5).

Conclusions Nano clinoptilolite seems to be a ciocomativle nano clay that in the case of nano sepiolite more studies are necessary but the effect is higher in cultures and animals.

Figures

Figure 1: Left A Cultures of Entamoeba histolytica treated with nano clinoptilolite. B Cultures of Entamoeba histolytica treated with nano sepiolite. Right Analyze with CFDA and PI that shows in green the live cells and in red the nucleus of dead cells.

Figure 2: A Macrophages of HPB treated with nano clinoptilolite. B Cultures of macrophages of HPB treated with nano sepiolite. Cells were analyzed by flow cytometry in a FacsCanto cytometer.

Figure 3: Accumulation of nano clays in the administration areas in CD1 mice.

References [1] Feynman RP, Leighton RB, Sands M. The

[2] [3] [4] [5] [6]

[7] [8]

370

[9]

Feynman Lectures on Physics, vol. 1. Reading MA: Addison Wesley Publishers; 1961.

S.M. Moghimi, A.C. Hunter, J.C. Murray, Faseb.

J. 19 (2005) 311–330.

U. Pison, T. Welte, M. Giersig, D.A. Groneberg, Eur. J. Pharmacol. 533 (2006) 341–350.

H.M. Kipen, D.L. Laskin, Am. J. Physiol. Lung Cell Mol. Physiol. 289 (2005) L696–697.

A. Nel, T. Xia, L. Madler, N. Li, Science 311 (2006) 622–627.

G. Oberdorster, E. Oberdorster, J. Oberdorster, Environ. Health Perspect. 113 (2005) 823–839.

M.C. Powell, M.S. Kanarek, W. M. J. 105 (2006) 16–20.

K. Thomas, P. Sayre, Toxicol. Sci. 87 (2005) 316–321.

R.F. Service, Science 304 (2004) 1732–1734.

Figure 4: Effect on the stomach morphology and colouration of CD1 mice treated with nano sepiolite.

Figure 5: Analytes for liver and kidney fuction that are in the normal range.

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Invited Visulaization of proteins in solution in situ

Rupert Tscheliessnig S. Ho Shin and A. Jungbauer

rupert.tscheliessnig@boku.ac.at ACIB, Muthgasse 11, 1190 Vienna, Austria

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References

[2] [3]

[4]

[5]

[6]

Angew. Chem. Int. Ed. 1999, 38, 1034. b) U.B. Sleytr, P. Messner, D. Pum, M. Sara, Crystalline Bacterial Cell Surface Protein, Landes/Academic Press, Austin, 1996. c) J. Lechner, F. Wieland, Annu. Rev. Biochem.

1989, 58, 173-194.

S. Mann, Angewandte Chemie-International Edition 47, 5306-5320(2008). a) D. Moll, C. Huber, B. Schlegel, D. Pum, U. B. Sleytr, M. Sara, Proceedings of the National Academy of Sciences of the United States of America, 2002, 99 ,14646. b) B. Aichmayer, M. Mertig, A. Kirchner, O. Paris, P. Fratzl, Adv. Mater. 2006, 18, 915. c) S. S. Mark, M. Bergkvist, X. Yang, L. M. Teixeira, P. Bhatnagar, E. R.Angert, C. A. Batt, Langmuir 2006, 22, 3763. c) W. Shenton, D. Pum, U. B. Sleytr, S. Mann, Nature, 1997, 585. a) J. E. Norville, D. F. Kelly, T. F. Knight, A. M. Belcher, T. Walz, J. Struct. Biol . 2007 , 160 , 313-323. b) H. Engelhard, J. Struct. Biol. 2007, 160 , 115-124. c) H. Engelhard, J. Struct. Biol.

2007 , 160 , 190-199.

S. Chung, S.-H. Shin, C. R. Bertozzi, J. J. DeYoreo, Proceedings of the National Academy of Sciences of the United States of America, 2010 . 107 (38) 16536-16541. a) C. Horejs, D. Pum, U. B. Sleytr, R. Tscheliessnig, J. Chem. Phys. 2008, 128 , 065106. b) C. Horejs, H. Gollner, Di. Pum, U. B. Sleytr, H. Peterlik, Al. Jungbauer, R. Tscheliessnig, ACS Nano, 2011, 5 (3), pp 2288â&#x20AC;&#x201C;2297. c) C. Horejs, D. Pum, U. B. Sleytr, H. Peterlik, A. Jungbauer, R. Tscheliessnig, J. Chem. Phys. 2010, 133 , 175102.

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[1] a) U.B. Sleytr, P. Messner, D. Pum, M. Sara,

371

Time dependent visualization of proteins in situ, e.g. their degradation during manufacturing and storage, the impact of salts upon their conformations are of broad interest in industrial biotechnology. The interest gets broader and arouses interest wihin the field of material sciences if it comes to self assemblies.

The outmost of cells of a broad spectrum of bacteria and archae are covered by layer proteins (S-layers). Consequently these are strongly involved in metabolic processes in response to the environment, serving numerous functions including structural stabilization, cell adhesion, pathogenicity, drug resistance and mineralization [1]. These two-dimensional crystals of S-layers have been recognized as a distinct class among numerous protein architectures found in nature [2, 4] that present various lattice periodicities commensurate with the dimensions of synthetic nano-materials, such as quantum dot and carbon nano-tubes. These long-range order self assemblies attractive bio-molecules for nano-scale templates for prospective nano-material engineering [3]. The assembly process in particular its detailed mechanism is understood if at all, poorly.

We combine Differential Scanning Calorimetry, in situ atomic force microscopy [5], Small Angle X-ray Scattering [6], Transmission electron microscopy as well as tomography with reversed Molecular dynamic simulations and reverse Monte Carlo simulations, to model possible crystallization pathways and conformational changes in situ.

Figures

372

Figure 1: Gray data refer to 3D experimental data of SbpA unit cell. a-c) Three complementary conformations of an SbpA monomer are superimposed. Pink circles refer to possible positions of secondary structure elements.

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Oral Magnetoresponsive hybrid microgels: close packed magnetite nanoparticles core - double layer polymeric shells with anionic or cationic functionalities 1

1

Rodica Turcu 1 I. Craciunescu 2 V. Socoliuc A. Petran1 2 C. Daia and 2 L. Vekas

rodica.turcu@itim-cj.ro

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microgels with cation exchange (CEX) or anion exchange (AEX) functionalities have been obtained by coating the NPCs with two polymer shells using layer by layer free radical polymerization of either N-isopropylacrylamide and acrylic acid (M-NIPAAAc) or N-isopropylacrylamide and 3acrylamidopropyl)-trimethylammonium chloride (M-NIPA-APTAC) in the presence of the crosslinker N,N-methylene bis-acrylamide and oxidant ammonium persulfate.

The TEM image of NPCs coated with SDS, figure 1 shows that magnetite nanoparticles stabilized with oleic acid are densely packed into spherical clusters coated with SDS with sizes in the range 100-500 nm. Dynamic light scattering and zeta potential measurements of the microgels gives values of the mean hydrodynamic diameter, Dh in the range 517-914 nm and zeta potential values between -23mV and -37mV for CEX microgels and between +35 mV and +39 mV for AEX microgels.

The magnetization vs. applied magnetic field at room temperature for NPCs stabilized with SDS and for magnetic microgels shows superparamagnetic behavior, the saturation magnetization has relatively high values in the range 46-56 emu/g, figure 2.

The chemical surface analysis of magnetic nanoparticle clusters and magnetic microgels was performed by X-ray Photoelectron spectroscopy (XPS). The coating of NPCs stabilized with SDS with double layer of polymers poly(N-isopropyl acrylamide) and polyacrylic acid is evidenced by the characteristic peaks in XPS spectra: (i) amide group N-C=O (286 eV) in C1s spectrum, NH (399 eV) in N1s spectrum, C=O (532.5 eV) in O1s spectrum, which are specific for pNIPA; (ii) carboxyl group O-C=O in C1s and O1s spectrum, specific for pAAc. XPS spectra of AEX magnetic

373

Magnetic nanoparticles (MNPs) well separated or in clusters, with proper surface functionalization usually dispersed in liquid carriers or embedded/encapsulated in polymeric networks, are the basic building blocks of a large variety of multifunctional carriers. The encapsulation of magnetic nanoparticles into polymeric micro/nanogel systems gives rise to hybrid magnetic carriers that combine the features of a polymeric gel with the interesting properties of magnetic nanoparticles and make them suitable for applications such as magnetically targeted drug delivery, hyperthermia treatments, magnetic resonance imaging contrast enhancement, magnetic carriers in bioseparation equipments [12].

We report the synthesis and characterization of magnetic microgels based on controlled clustering of hydrophobic magnetite nanoparticles and coating with different polymeric shells of poly(Nisopropylacrylamide), polyacrylic acid, poly(3acrylamidopropyl)-trimethylammonium chloride.

The oil in water miniemulsion method [3] was applied for the preparation of magnetic nanoparticles clusters (NPCs) using toluene based magnetic nanofluid (MF) containing Fe3O4 nanoparticles stabilized with a hydrophobic layer of oleic acid. The MF was added to the aqueous solution containing sodium dodecyl sulphate (SDS) as surfactant and treated ultrasonically to obtain small stable droplets with NPCs. The as prepared magnetic miniemulsion was heated to remove the toluene and then was carefully washed several times with methanol-water mixture, magnetically separated and redispersed in water. Stable aqueous dispersions of magnetic nanoparticles clusters coated with the surfactant SDS were used for encapsulation into polymers. Magnetic

NANOBIO&MED 2013

National Institute R&D for Isotopic and Molecular Technologies, 65-103 Donath Street, 400293 Cluj-Napoca, Romania 2 Romanian Academy-Timisoara Branch, Center for Fundamental and Advanced Technical Research, Lab. Magnetic Fluids, Timisoara, Romania

microgel, confirm the double layer polymer coating of SDS stabilized NPCs with poly(Nisopropyl acrylamide) and poly(3-Acryloamidopropyl trimethylammonium chloride), figure 3.

The CEX and AEX magnetic microgels exhibit good stability, high saturation magnetization/large magnetic moment, response to moderate magnetic fields, being promising materials for applications in high gradient magnetic separation and nanomedicine.

Acknowledgements: Support by the European project FP7 No. 229335 MAGPRO²LIFE and the Romanian project 83EU/2010 is acknowledged.

References

Figure 3: High resolution XPS spectra for C1s, O1s, N1s, S2p, core levels from AEX microgel M-NIPA-APTAC obtained by coating of SDS stabilized NPCs with poly(N-isopropyl acrylamide) and poly(3Acryloamido-propyl trimethylammonium chloride).

[1] . Lu, M. Ballauff, Progress in Polymer Science, 36 (2011) 767-792.

[2] N.S. Satarkar, D. Biswal, J.Z. Hilt, Soft Matter, 6

(2010) 2364-2371.

[3] P. Qiu, C. Jensen, N. Charity, R. Towner, C.

Mao, J. AM. CHEM. SOC. 132 (2010) 17724â&#x20AC;&#x201C; 17732.

Figures

Figure 1: TEM images of NPCs stabilized with SDS prepared by oil in water miniemulsion method.

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Figure 2: Magnetization curves at room temperature for NPCs and magnetic microgels M-NIPA-AAc (CEX), M-NIPA-APTAC (AEX).

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Oral Characterization of Functionalized, Magnetic Nanoparticles

Barbara Unterauer M. Rohn and M. Mühlberger

Profactor GmbH, Im Stadtgut A2, 4407 Steyr-Gleink, Austria

barbara.unterauer@profactor.at

Acknowledgements: This work was supported by Die Österreichische Forschungsförde rungsge sellschaft FFG. Part of this work was supported by the NanoInk and NanoShape projects of the NSI project cluster in the Austrian nanoinitiative (www.nanoscience.at). Part of this work was also supported by the MacroFun project in the COMET initiative (www.macrofun.tugraz.at).

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References [1] Kovalenko M.V., Bodnarchuk M.I., Lechner

R.T., Hesser G., Schäffler F., Heiss W., Journal of American Chemical Society 129 (2007) 6352.

Figure 1: Reaction scheme of the particle synthesis. These particles are characterized with AFM.

NANOBIO&MED 2013

Figures

Figure 2: Size and size distribution of particles on the example of a 1μm AFM image.

375

Nanoparticles play an important role in various fields like pharmaceuticals, advanced materials, environmental detection and monitoring.

Obviously there is not a single best technique to characterize nanoparticles, but AFM is a very suitable technique offering qualitative and quantitative information on the particle.

In this study we are dealing with the characterization of iron-oxide nanoparticles. They were synthesized in a batch process based on the protocol described by Kovalenko et al [1] and shown in Figure 1 below. After particle formation the oleate shell was replaced by hydrophilic ligands. In one special case we functionalized them with a dye to create a so-called laccase sensor.

For the characterization we were interested in qualitative and quantitative information on physical properties like size, morphology and magnetic properties and statistical information on size distribution.

We will show the particle synthesis, the various functionalization products, the sample preparation for the AFM measurements and the results of the measurements.

Oral Ruben Van Roosbroeck 1 T. Stakenborg 1 W. Van Roy J. Lammertyn2 and 1 L. Lagae

1

Ruben.Vanroosbroeck@imec.be

Imec, Kapeldreef 75, Leuven, Belgium KUL (Mebios), Kasteelpark Arenberg 30, Leuven, Belgium

2

Magnetic nanoparticles show great promise and are widely investigated as agents in various biomedical applications including analyte detection, biosensing, drug delivery and imaging. A particular field of interest is magnetic resonance imaging (MRI) where such particles can serve as T2 contrast enhancers. Most of the reported research related to MRI is focussing on superparamagnetic nanoparticles, synthesized by bottom-up wet chemistry methods[1]. These magnetic particles are, however, restricted to the superparamagnetic limit to avoid magnetic remanence and aggregation in the absence of a magnetic field.

This restriction therefor implies a size limit (20-25 nm) and consequently a limited magnetic moment per particle. The ideal particle diameter for contrast agents in MRI-experiments unfortunately exceeds this limit[2]. Moreover, bottom-up synthesis often results in polydisperse particle suspensions.

To overcome these issues, synthetic antiferromagnetic (SAF) particles are proposed here as alternative T2 contrast agents for MRI applications. These particles are composed of two ferromagnetic layers, separated by a non-magnetic layer (Figure 1). Using the interlayer exchange coupling effect, synthetic antiferromagnetism can be produced which mimics superparamagnetic behavior (i.e. no magnetic moment in the absence of a magnetic field). Size and shape can be controlled through a range of litohgraphic methods to produce highly magnetic and monodisperse particle suspensions. To fabricate the SAF particles, we used colloidal lithography with monodisperse polystyrene beads (60-200 nm) serving as an etch mask. By controlling the size of the polystyrene beads, the final SAF particles could be fine-tuned in size. After synthesis on wafer

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1,2

Synthetic Antiferromagnetic Nanoparticles As Contrast Agents In MRI

scale and a lift-off step, the particles were suspended in aqueous solution and chemically stabilized.

As intended, the particles showed no magnetic remanence despite the fact that they are composed of ferromagnetic materials (Figure 2).

To show the performance of the SAF particles as contrast agents simulations were performed and experimental relaxivities were determined. Using simulations the effect of size, composition and shape of the particles on the relaxivity was demonstrated. Second, experimental relaxivities r2 up to 350 s-1mM-1 were achieved for NiFe-based particles which is competitive with conventional superparamagnetic nanoparticle suspensions[3].

These proposed SAF particles, behaving like superparamagnetic particles without being restricted in size, show a great potential for MRI applications.

References [1] Hilgner I, Kaiser WA, Nanomedicine 7 (2012) 1443-1459.

[2] Vuong QL, Gillis P, Gossuin Y, Journal of

Magnetic Resonance 212 (2011) 193-48.

[3] Vuong QL, Berret JF, Fresnais J, Gossuin Y,

Sandre O, Advanced Healthcare Materials 1 (2012) 502-512.

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Figures

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Figure 2: SQUID-measurement of suspended synthetic antiferromagnetic nanoparticles with a mean diameter of 100 nm.

The schematics show the magnetization of the magnetic layers inside the particle. At zero field no magnetic remanence is observed due to the SAF-coupling of the magnetic layers.

NANOBIO&MED 2013

Figure 1: Electron microscopic image of the fabricated synthetic antiferromagnetic nanoparticles with a mean diameter of 100nm.

The inset (upper right) shows a magnification of a single particle.

The SAF particle is composed of two NiFe layers (black) in the center separated by a thin Ru-spacer (bright). A gold layer on top and bottom (thick bright layers) surround the SAF stack.

Oral Ladislau Vékás 1 1 V. Socoliuc , F. Bălănean 1 1 A. Moaca , C. Daia D. Susan-Resiga1, O. Marinică1 1 2 N.C. Popa , T. Borbáth 2 3 T. Boros and R. Turcu

1

vekas@acad-tim.tm.edu.ro vekas.ladislau@gmail.com

Romanian Academy-Timisoara Branch (RATB), 24 Mihai Viteazul Str., Timisoara, Romania 2 ROSEAL Co., N. Balcescu Str. 5A. Odorheiu Secuiesc, Romania 3 National Institute of R&D for Isotopic and Molecular Technologies (NIIMT), 65-103 Donath Str., Cluj-Napoca, Romania

High magnetic moment nano – or micron sized carriers with superparamagnetic behavior and various added functionalities provide advanced therapeutic, diagnostic or bioprocessing capabilities [1]. The strongly magnetoresponsive character and appropriate design of surface properties are among the main requirements for nano- or micro-adsorbents to be used in magnetic bio-separation processes, such as protein purification [2] involving high gradient magnetic separation (HGMS) step [3]. The building blocks for the fabrication of magnetoresponsive microcarriers are the subdomain magnetite nanoparticles surface coated by biocompatible molecular layers, such as carboxylic (lauric, myristic, oleic) acids, which ensure their stabilization-dispersion in an appropriate carrier liquid, to obtain stable magnetic nanofluids - the primary materials for the envisaged magnetic nanocomposites.

In this work we report on kg scale synthesis of magnetite nanoparticles with biocompatible coating used as primary particles for the preparation of magnetoresponsive hybrid nanocomposites designed for magnetic separation [4] or drug targeting [5]. Controlled clusterization of magnetite nanoparticles from light hydrocarbon or water based magnetic nanofluids is a widely applied procedure to synthesize polymer-magnetic nanoparticles hybrid microspheres with sizes well above 50 nm having both high magnetic moment and superparamagnetic behavior [4, 5]. The synthesis procedures of magnetite nanofluids (fig.1) using the chemical co-precipitation method developed on laboratory level [6] were optimized and scaled up to achieve the main characteristics required for the preparation of magnetoresponsive microspheres. The procedures

378

1

Hydrophobic and hydrophilic magnetite nanoparticles: non-polar and polar magnetic nanofluids designed for magnetic carriers manufacturing

were validated by using the data of TEM, DLS, SLS, VSM, magnetogranulometry and rotational rheometry investigations: mean particle size 6-9 nm (figs.2 and 3), biocompatible surface coating (vegetable origin oleic acid; Merck product), high colloidal stability (reduced fraction of small agglomerates; hydrodynamic mean size below 50 nm, figs.4 and 5), well screened magnetic dipoledipole interactions between particles also at close packing (fig.6; ϕ= 0.2 corresponds to approx. 0.5 hydrodynamic volume fraction); superparamagnetic behavior and high specific magnetic moment of surfacted magnetite nanoparticles (fig.7; approx. 50 emu/g), reduced costs.

Acknowledgement: Financial support by the European project FP7 No. 229335 MAGPRO²LIFE and the Romanian project 86EU/10CF/2010 is acknowledged.

References [1] L.H. Reddy, J.L. Arias, J. Nicolas, P. Couvreur, Chemical Reviews, 112 (2012) 5818-5878.

[2] C. Müller, K. Wagner, K. Frankenfeld, M.

Franzreb, Biotechnology Lett., 33(5) (2011) 929-936.

[3] G. N. Brown, C. Müller, E. Theodosiou, M. Franzreb, O.R.T. Thomas, Biotechnology and Bioengineering, DOI: 10.1002/bit.24842 (2013).

[4] M.S.A. Darwish, U. Peuker, U. Kunz, T. Turek, J. Mater. Sci., 46 (2011) 2123-2134.

[5] L. Vékás, EtelkaTombácz, RodicaTurcu, I. Morjan, M.V. Avdeev, Theodora KrasiaChristoforou, V. Socoliuc, in: Nanomedicine-

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Basic and Clinical Applications in Diagnostics and Therapy (Ed. ChristophAlexiou) Karger Publ. Basel, Switzerland, 2 (2011) 35-52.

[6] L. Vekas, M.V. Avdeev, D. Bica, in: NanoScience in Biomedicine (Ed. Donglu Shi, Springer USA, 2009) 645-70.

Figures Figure 5: Hydrodynamic size distribution of hydrophobic magnetite NPs (Fe3O4.OA).

Figure 6: Dependence of magnetic mean size and standard deviation on the solid volume fraction of magnetite NPs dispersed in hydrocarbon carrier.

Figure 2: TEM of magnetite NPs dispersed in hydrocarbon carrier liquid.

Figure 3: Size distribution of magnetite NPs.

NANOBIO&MED 2013

Figure 1: Magnetic nanoparticle synthesis procedures-main steps.

Figure 7: Full magnetization curve for hydrophobic magnetite organosol (Fe3O4.OA).

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379

Figure 4: Hydrodynamic size distribution of hydrophilic magnetite NPs (Fe3O4.(OA+OA)).

Invited Precisions synthesis of nanocrystals and their use in biomedical applications

Horst Weller

weller@chemie.uni-hamburg.de Department of Chemistry, University of Hamburg Center for Applied Nanotechnology Hamburg (CAN) Interdisciplinary Nanoscience Center Hamburg (INCH) The Hamburg Center for Ultrafast Imaging (CUI) Grindelallee 117 - 20146 Hamburg, Germany

380

We report on the precision synthesis of fluorescent and magnetic nanocrystals using a preparative flow reactor. Experimental design is used to determine the crucial parameters and their influence on particle growth and size distribution.

In the second part of the talk, we will present biological applications of nanocrystals. In particular, we will show a comparison of different shell materials in respect of unspecific cell adhesion and uptake and discuss parameters controlling these processes. Nanocrystals, which were equipped with cross-linked block-copolymer ligand shells or encapsulated by emulsion polymerization show extraordinary low unspecific cell interactions. We present various techniques for bio-conjugation with recognition molecules and show examples for specific cell and tissue targeting. In-vitro and in-vivo fluorescence and MRI data will be discussed

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Invited Biomedical applications of magnetic nanoparticles: from cell imaging to tissue engineering

Claire Wilhelm

claire.wilhelm@univ-paris-diderot.fr

Laboratoire Matière et Systèmes Complexes, UMR 7057, CNRS and Université Paris Diderot, France

References

[2]

[3]

[4]

[5]

[6]

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3161. Levy M, Luciani N, Alloyeau D, Elgrabli D, Deveaux V, Pechoux C, Chat S, Wang G, Vats N, Gendron F, Factor C, Lotersztajn S, Luciani A, Wilhelm C, Gazeau F, Biomaterials. 32 (2011) 3988. Lesieur S, Gazeau F, Menager C, Wilhelm C. J. Mat. Chem. 21, 14387-14393 (2011). Lartigue L, Wilhelm C, Servais J, Factor C, Dencausse A, Bacri J-C, Luciani N, Gazeau F. ACS Nano, 6 (2012) 2665.

Wilhelm C, Phys Rev Lett 101 (2008) 028101.

Robert D, Nguyen TH, Gallet F, Wilhelm C, PLoS one 5, (2010) e10046. Robert D, Pamme N, Conjeaud H, Gazeau F, Alexander Iles A, Wilhelm C. Lab on Chip, 11 (2011) 1902.

Robert D, Fayol D, Le Visage C, Frasca G, Brulé S, Ménager C, Gazeau F, Letourneur D, Wilhelm C, Biomaterials, 31 (2010) 1586.

Chaudeurge A, Wilhelm C, Chen-Tournoux A, Farahmand P, Bellamy V, Autret G, Larghéro J, Thiam R, Desnos M, Hagège A, Gazeau F, Clément O, Menasché P. Cell Transplantation, 21 (2012) 679.

Fayol D, Luciani N, Lartigue L, Gazeau F, Wilhelm C. Adv Healthcare Materials, 2 (2013) 312.

Di Corato R, Gazeau F, Le Visage C, P Levitz P, Letourneur D, Luciani N, Tillement O, Wilhelm C. ACS nano, In revision.

Frasca G, Gazeau F, Wilhelm C. Langmuir. 25 (2009) 2348. Fayol D, Frasca G, Le Visage C, Gazeau F, Luciani N, Wilhelm C. Advanced Materials, In press (2013). Patent B1224FR00.

Fayol D, Le Visage C, Ino J, Gazeau F, Letourneur D, Wilhelm C, Cell Transplant Jan 2 (2013).

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[1] Wilhelm C, Gazeau F, Biomaterials, 29 (2008)

381

Recent advances in cell therapy and tissue engineering opened new windows for regenerative medicine, but still necessitate innovative techniques to create and image functional tissues.

One promising approach is to associate magnetic nanoparticles with cells in order to supply them with sufficient magnetization to be detectable by MRI [1] or manipulated by magnetic forces [2], while maintaining cell viability and functionalities.

A few years ago, we proposed the use of anionic iron oxide nanoparticles as efficient agents for cell internalisation without impacting cell functions [1].

Recently we examined the influence of the amount of internalized iron and the state of nanoparticle aggregation on the capacity for mesenchymal stem cell differentiation and MRI single cell tracking [3].

We then demonstrated that high resolution Magnetic Resonance Imaging (MRI) allowed combining cellular-scale resolution with the ability to detect two cell types simultaneously at any tissue depth [4]. In parallel, we adressed the challenge to create a functional tissue from stem cells in vitro. The aim was to confine stem cells in three dimensions at the millimetric scale by using home-designed miniaturized magnetic devices, in order to create cellular patterns for cartilage tissue engineering [5]. The labeling of endothelial precursors provided as well new possibilities to create potential vessel substitutes [6]. Taken togeter, these results have fundamental implications for the use of magnetic nanoparticles for cell therapy, from MRI imaging studies of stem cell fate to tissue engineering.

Figures

382

Figure 1: From left to right : Magnetic nanoparticles are confined within intracellular endosomes, providing the cell with enough magnetization to be detected individually on high resolution MRI scans - Magnetically driven fusion of stem cell aggregates assembled by micromagnets results in the formation of a continuous tissue layer containing abundant cartilage matrix - A technological approach combining a tubular scaffold and magnetic endothelial cells allows creating a pluricellular and organized vascular graft, with in depth MRI detection of individual cellular components.

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Oral 1

Graphene/graphene oxide – multifunctional platform for drug delivery and photodynamic therapy in cancer treatment

Malgorzata Wojtoniszak

1

mwojtoniszak@zut.edu.pl

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drug release from graphene oxide in physiological solution – phosphate buffered saline (PBS) containing different biocompatible polymers will be investigated. It was discovered that dispersion of MTX-GO in poly sodium-4-styrene sulfonate (PSS) and poly ethylene glycol (PEG) resulted in significant increase of the release time. The material was characterized with transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) and UV-vis spectroscopy. Furthermore, antineoplastic action against human breast adenocarcinoma cell line MCF7 of MTX-functionalized graphene oxide and empty graphene oxide was explored. It was found that the anti-proliferative activity of MTX-GO depended on dispersant used to stabilize the suspension.

References [1] H. Park, J.A. Rowehl, K.K. Kim, V. Bulovic, J. Kong, Nanotechnology, 21 (2010) 505204.

[2] T. Truong-Huu, K. Chizari, I. Janowska, M.S.

Moldovan, O. Ersen, L.D. Nguyen, M.J. Ledoux, C. Pham-Huu, D. Begin, Catalysis today, 189 (2012) 77-82.

[3] Y. Li, G. Zhao, C. Liu, Y. Wang, J. Sun, Y. Gu, Y. Wang, Z. Zeng, Intern. J. Hydrogen Energy, 37 (2012) 5754–5761.

[4] H. Wang, T. Chen, S. Wu, X. Chu, R. Yu, Biosensors and Bioelectronics, 34 (2012) 8893.

[5] X. Yang, Y. Wang, X. Huang, Y. Ma, Y. Huang, R. Yang, H. Duan, Y. Chen, Journal of materials chemistry, 21 (2011) 3448–3454.

383

Recently, graphene has attracted a great scientific interest in many fields such as electronics, gas storage, catalysis, and medicine among others [14]. Because of its electronic, optical and structural properties it has been explored as a carrier of variety molecules such as drugs for cancer chemotherapy, ferromagnetic for hyperthermia or photosensitizers for photothermal therapy and photodynamic therapy [5-7].

In this study, potential of graphene oxide biomedical applications will be presented. Firstly, in vitro cytocompatibility tests of graphene oxide and reduced graphene oxide dispersed in different polymers will be shown. Here, type of dispersant and concentration of nanomaterials effects on mice fibroblast cells (L929) viability will be reported. Secondly, graphene oxide (GO) functionalization with methylene blue (MB) and its performance in singlet oxygen generation (SOG) under irradiation of laser with excitation wavelengths of 785 nm will be reported.

Remarkably, it was noted that GO functionalized with MB (MB-GO) showed an enhanced efficiency in singlet oxygen generation compared to pristine MB. The efficiency in SOG was detected by photobleaching of 9,10anthracenediylbis(methylene)dimalonic acid (ABMDMA). Detailed characterization of the obtained material was carried out with UV-Vis spectroscopy, Raman spectroscopy, FT-IR spectroscopy, and confocal laser scanning microscopy. Interestingly, in contrast to previous study [8], fluorescence confocal microscopy demonstrated that the adsorption of MB on GO resulted in an enhanced fluorescence when the material was excited with light from blue to orange range. Finally, covalent functionalization of graphene oxide with anticancer drug methotrexate (MTX) through amide bonding will be shown. A kinetics of the

NANOBIO&MED 2013

West Pomeranian University of Technology in Szczecin, Institute of Chemical and Environment Engineering, Pulaskiego 10, 70-322, Szczecin, Poland 2 Pomeranian Medical University, Department of General Pathology, Powstańców Wlkp. 72, 70-111, Szczecin, Poland 3 Pomeranian Medical University, Department of Pharmacology, Powstańców Wlkp.

72, 70-111, Szczecin, Poland

D. Rogińska2 M. Perużyńska3 M. Kurzawski3 M. Droździk3 B. Machaliński2 and E. Mijowska1

[6] L.Z. Bai, D.L. Zhao, Y. Xu, J.M. Zhang, Y.L. Gao,

L.Y. Zhao, J.T. Tang, Materials letters, 68 (2012) 399–401.

[7] K. Yang, L. Hu, X. Ma, S. Ye, L. Cheng, X. Shi, C. Li, Y. Li, Z. Liu, Advanced materials, 24 (2012) 1868–1872.

[8] K. Haubner, J. Murawski, P. Olk, L.M. Eng, C. Ziegler, B. Adolphi, E. Jaehne, Chemphyschem A European Journal Of Chemical Physics And Physical Chemistry, 11 (2010) 2131-2139.

Figures

Figure 1: AFM image of graphene oxide functionalized with methotrexate (MTX-GO).

384

Figure 2: Fluorescent confocal images of MB-GO obtained in different excitations (blue: A, green: B, orange: C, far red: D).

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Oral Alexey Yashchenok 1 A. Masic 2 D. Gorin B. Parakhonskiy3,4 1 H. Möhwald and 1,5 A. Skirtach

1

alexey.yashchenok@mpikg.mpg.de

Max Planck Institute of Colloids and Interfaces, Department of Interfaces, Germany Saratov State University, Department of Nano- and Biomedical Technologies, Russia 3 University of Trento, BIOtech center, Italy 4 Shubnikov Institute of Crystallography, Russia 5 Ghent University, Department of Molecular Biotechnology, Belgium 2

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increase of SNR due to SERS allows visualization and detection of biomolecules. The Raman probes developed in this work can be ubiquitously applied for molecular imaging and sensing in cells and tissues.

We continue our study for assembling of gold nanoparticles within pores of calcium carbonate microparticles.

Porous calcium carbonate microparticles exhibited superior performance in comparison to smooth silica particles. Porosity which can be linked to adsorption of particles is identified as a key mechanism leading to an increased nanoparticle adsorption and enhanced label-free Raman based detection [2]. Using these particles, label-free detection of important biomolecules such as glucose (Fig. 2) and bovine serum albumin is demonstrated at concentrations of nM–μM levels. Such an approach is attractive for developing biomarker sensing at concentrations corresponding to healthy and diseased individuals.

References [1] A. Yashchenok. A. Masic, D. Gorin, B.S. Shim,

N.A. Kotov, P. Fratzl, H. Möhwald, A. Skirtach, Small, 9 (2013) 351.

[2] A.M. Yashchenok, D. Borisova, B.V. Parakhonskiy, A. Masic, B.E. Pinchasik, H. Möhwald, and A.G. Skirtach, Annalen der Physik Special Issue: Plasmonic Sensors, 524 (2012) 723.

385

Self-assembly of colloidal noble metal nanoparticles into macroscopic one, two, and three-dimensional arrays either flat or curved substrate is very promising approach, that is to developing sensors based on plasmonic effect.

Layer-by-Layer (LbL) deposition is established method for fabrication of multicomponent structures on the solid support in the nanoscale.

We applied in this work LbL approach to fabricate nanoplasmonic sensors based on gold nanoparticles adsorbed over carbon nanotubes network and also introduced those into pores of calcium carbonate (CaCO3) microparticles.

Roughened structure of developed colloids allowing us to use them as detectors of molecules in Raman experiments based on surface enhancement Raman scattering effect (SERS).

Today SERS is one of powerful analytical tool, especially in term of label-free purposes. Compare with fluorescence imaging SERS overcomes photobleaching and provides highly detailed molecular information. Since the discovery of surface enhanced Raman scattering novel platforms have evolved and various approaches to SERS substrates have been introduced.

Currently, we achieved remarkable high Raman scattered signal from probe based on silica core coated with carbon nanotubes subsequently functionalized with gold nanoparticles aggregates.

Functionalized carbon nanotubes provide easy localization at extremely low laser powers and increased roughness necessary for highly efficient SERS amplification [1]. Upon intracellular incorporation probes significantly enhance molecular fingerprints of biomolecules commonly found inside NIH3T3 fibroblast and enable fast acquisition rates at laser powers completely harmless to living cells (Fig. 1). Remarkable

NANOBIO&MED 2013

1

Layer-by-Layer assembly of nanocomposite colloidal probes for Raman-based detection of biomolecules

Figures

Figure 1: Raman spectroscopic imaging of a living fi broblast cell with incorporated colloidal probes. (a) Linear combination of the averaged single spectra b) Characteristic for cell compartments (green-cytoplasm, blue-nucleus, yellow-carotenoids) and goldnanoparticle- SWCNT functionalized colloidal probes (red). (c) Intracellular SERS signal recorded at the surface of the probe.

386

Figure 2: SERS spectra of D-Glucose molecules with varying concentration. The characteristic peak at 1130 1/cm is pointed out.

All measurements were made using 785 nm laser (10 mW)..

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Oral In vitro diagnostics of microbial cells and their antibiotic resistance using nanostructured anodic aluminum oxide growth platforms 1

1

Tatiana Zimina 2 L. Kraeva 1 E. Sokolova A. Soloviev1 1 V. Luchinin and 2 G. Hamdulaeva

tmzimina@gmail.com

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functional elements of the system are presented including culture growth platform (Figure 1) based on porous anodic alumina (PAA), AST diffusion and laser speckle optics turbidimetry modules are discussed. The PAA membranes with regular pore arrays and nano porous supports for the cell growth are fabricated using MEMS/MOEMS technologies. These elements could be incorporated into an integrated system for isolation and reliable direct identification of a range of pathogens, as well as express determination of their viability and threshold concentrations of various classes of antibiotics in the “point-of-care” format. The structured colonies growth platform fabricated on the basis of microporous aluminium oxide (AAO) is a principal part of the system1, which could facilitate direct CB method in terms of analysis time, accuracy and point-of-care availability. The main feature of such platform is a possibility to cultivate homogeneous juvenile colonies, sufficient for identification. Using such juvenile colonies accelerates microbiological analysis by factor of 3 and above as well as provides new opportunities for process automation. Isolated small colonies are grown at spatially arranged growth spots as micropores covered with nanoporous AAO. After limited growth time (lower than in conventional microbiological procedures), when colonies achieve a moderate size of approximately 8 to 128 organisms, they should be cautiously displaced.

The separation of juvenile colonies from original “nesting sites” is made by microhydroblow generated from underneath by micro pump. In this case micropores are used as jets to form a hydraulic impulse. Then microflow moves them to the next functional elements. This allows to prepare a sample ready for aligning and transport

387

The development of tools for express analysis of human specimens related to aggravated problem of bacteriological threats, combined with the drug resistance is becoming increasingly important.

Conventional in vitro microbial cells identification and antibiotic resistance diagnosis is based on culture growth of microorgranisms.

Implementation of this direct approach is usually labour intensive, low throughput and slow. The amplification of clinically relevant DNA by the Polymerase Chain Reaction (PCR) and micro arrays provides data on potential pathogenicity while in clinical use it is crucial to have information on resistance of an actual pathogen from a particular clinical case to correctly select medication. Thus, improving culture based (CB) diagnosis methods could contribute to solving the drug resistance problem, via facilitating the optimal and timely choice of medication. Main limiting factors of CB methods, which restrict their express implementation, are: microorganism growth rate (to make a sample available for manual operations), pathogen recognition and determination of its viability in response to antibiotic exposure (antibiotic susceptibility testing - AST). Miniaturization and heterogeneous integration of living bacteria and MEMS components further contribute to resolving the problems associated with classical CB approaches.

To produce a miniaturised automated platform, appropriate for integration to carry on total microbiological procedure automatically. The presented devise consists of a number of functional modules, namely: colonies growth platform, microfluidic transport system with liquid key for colonies sorting, express pathogen recognition system, AST growth and viability determination module etc. In this work, essential

NANOBIO&MED 2013

St. Petersburg Electrotechnical University “LETI”, 5 Professora Popova str., St. Petersburg, Russia 2 Pasteur Institute of Epidemiology and Microbiology, 14 Mira str., St. Petersburg, Russia

to other functional elements of total system intended for pathogen identification, sorting and AST. The growth spots are formed in a single technological process of anodic oxidation. The growth platform is intended for further integration targeted at development of full automatic pointof-care microbiological analyser including AST module, with disposable microbial platforms and analysis time 6 – 8 hours. The application of the module in analysis of a number of microbiological samples is described.

Acknowledgement: The work was funded by FMBA RF grant No 40.002.12.0 of 20.02.2012 and by the Russian Federation Ministry of Education and Science under Federal Grant Program “Scientific and Educational Human Resources of Innovative Russia”, The State Contracts No 14.B37.21.0568 and No 14B37210793.

References [1] Tatiana M. Zimina1, Victor V. Luchinin1,

Figures

Figure 1: (a) Schematic representation of growth chamber: 1 – AAO substrate, 2 – micropore, 3 – nanoporous Al2O3 membrane permeable for nutrient, 4 – cell, 5 – juvenile colony, 6 – direction of microhydroblow displacing colonies; (b) AAO platform with micropores; (с) the same as (b) with microbial cells; (d) juvenile colony of Staphylococcus aureus, growth time t = 1 h, number of cells N ~ 800, size of colony ~10 microns, (e) juvenile colony of Staphylococcus epidermidis, t = 1 h; (f, g) nanoporous Al2O3, section and top view correspondingly.

388

Aleksei V. Soloviev1, Nadezhda V. Kuznetsova1, Nikolai I. Mukhurov2, Irina V. Gasenkova2, Liudmila A. Kraeva3, Galina Ja. Tseneva3, Functional Elements of Laboratoryon-a-Chip for Express Identification and Antimicrobial Susceptibility Testing of Bacterial Respiratory Tract Infections, Proc. of.

“Lab-on-Chip”, Dublin, 27-29 May, 2010.

[2] T. M. Zimina, A. V. Soloviev, V. V. Luchinin, E. V. Sokolova, A method of microbial cells growth and a device for its realization. Patent app. N 2011154770/10 (082262). Filed 29.12.2011.

[3] N. I. Mukhurov, I. V. Gasenkova, I. F. Kotova, E. A. Tyavlovskaya, T. M. Zimina, I. G. Kazarin, N. I. Latnikova, V. V. Luchinin. Nanopore structures of anodic aluminium oxide for analytical Microsystems. Proc. of. “Dielectrics2008”. St. Petersburg.

[4] L. Kraeva, G.Tseneva, T.Zimina. Express diagnostics of toxin–positive strains of C. diphtheriae. // Tenth International Meeting of the European Laboratory Working Group on Diphtheria, ELWGD, Larnaca, Cyprus, 5-7 November 2008.

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PPM

2013

Index PPM2013 Contributions Invited

Pag

■ Javier Aizpurua (CFM/CSIC & DIPC, Spain) "The quantum regime in tunneling plasmonics"

399

■ Remi Carminati (ESPCI, France) "Weak and strong coupling to photonic modes in nanoscale disordered media"

407

■ Alfonso Cebollada (IMM-CNM-CSIC, Spain) "Magnetoplasmonics: combining magnetic and plasmonic functionalities"

410

■ Aristide Dogariu (Univ. of Central Florida, USA) “Optical Action in Complex Media”

-

■ Francisco J. García-Vidal (UAM, Spain) "Theory of strong coupling between quantum emitters and propagating surface plasmons"

424

■ Rainer Hillenbrand (CIC nanoGUNE, Spain) "Infrared Near-field Spectroscopy - From Nanoscale Chemical Identification of Polymers to Real-space Imaging of Graphene Plasmons"

431

■ Tobias Kippenberg (EPFL, Switzerland) "Cavity Optomechanics: Exploring the coupling of light and micro- and nanomechanical oscillators"

433

■ Philippe Lalane (IOGS, Palaiseau, France) "Purcell factor of photonic and plasmonic nanoantennas"

437

■ Maciej Lorenc (IPR- UMR6251, Rennes, France) "Femtosecond Spin-State Photoswitching of Molecular Nanocrystals"

442

■ Lukas Novotny (ETH Zurich, Switzerland) "Cascaded Field Enhancement with Self-Similar Antennas"

444

■ Romain Quidant (ICFO, Spain) "Controlling the interaction of light with the very small"

451

■ Anne Sentenac TBC (Institut Fresnel- UMR 7249, Marseille, France) "Improving the resolution of optical far-field microscopes using structured illumination"

453

■ Niek F. van Hulst (ICFO, Spain) "Non-dipolar & magnetic interactions with optical antennas"

458

■ Martin Wegener (Karlsruhe Inst. of Technology, Germany) "Three-dimensional optical laser lithography: No limits?"

461

■ Diederik Wiersma (LENS, Italy) Abstrat not provided by the speaker

-

■ Anatoly Zayats (King's College London, UK)

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462

391

"Active Nanoplasmonics: Loss, Gain and Nonlinearity"

Oral

Pag

■ Rodrigo Alcaraz de la Osa (University of Cantabria, Spain) 400

"Quantum effects in small plasmonic particles in the UV-VIS range"

■ Pablo Alonso-González (CIC nanoGUNE, Spain) Visualizing the near-field coupling and interference of bonding and anti-bonding modes in infrared dimer nanoantennas""

402

■ Hidehiko Asanuma (Max Planck Institute of Colloids and Interfaces, Germany) "Molecular self-assembly towards macroscale ordering: application as SERS substrate"

404

■ Alvaro Blanco (ICMM-CSIC, Spain) 405

"Observation and use of internal water in silica photonic structures"

■ Alexandre Cazé (Institut Langevin ESPCI Paristech CNRS, France) 408

"Cross Density of States and spatial coherence in complex plasmonic systems"

■ Alexander Chizhik (Universidad del País Vasco, Spain) "Mechanisms of magnetization reversal in magnetic wires. Magneto-optical study"

411

■ Eduardo Coutino Gonzalez (KULeuven, Belgium) "Luminescent zeolite composites with outstanding external quantum efficiency using silver clusters as dopants"

413

■ Nuno de Sousa (Universidad Autonoma de Madrid, Spain) 415

"Theoretical study of the magneto-optical activity in Au/Co/Au disks"

■ Ruben Esteban (Centro de Fisica de Materiales, Centro Mixto CSIC-UPV/EHU and Donostia International Physics Center (DIPC), Spain)

416

"Linear chains as optical building blocks of complex metallic clusters"

■ Josep Ferré i Borrull (Universitat Rovira i Virgili, Spain) "Simplified Method for 3D-structured Nanoporous Anodic Alumina with stop bands in the visible"

418

■ Luis S. Froufe-Perez (CSIC, Spain) "Wide band transparent metallo-dielectric nanowires at telecommunications wavelengths"

420

■ Juan Galisteo-López (ICMM-CSIC, Spain) 422

"FRET-mediated amplified spontaneous emission in biopolymer complexes"

■ Manuel Gómez (CIQUS, Center for Research in Biological Chemistry and Molecular Materials, Spain) 425

"New SERS substrates made of polymers and Al, cheap and highly efficient"

■ Jordi Gomis Bresco (Institut Català de Nanotechnologia (ICN), Spain) "Optomechanical coupling in 1D corrugated structures with complete dual photonic and phononic band gap"

427

■ Juan Bautista Gonzalez Diaz (CIC nanoGUNE, Spain) "Quantitative Magneto-Optical Characterization of Diffusive Reflected Light from Rough Steel Samples"

428

■ Marcin Grzelczak (Universidad de Vigo, Spain) 430

"Optical response of individual Au-Ag@SiO2 hetero-dimers"

■ Magnus Jonsson (Delft University of Technology, Netherlands) 432

"Nanopores for Bioanalytical Sensing"

■ Oleksandr Kovalenko (Institut des Molécules et Matériaux du Mans, France) 434

"Magnetization switching by ultrashort acoustic pulses"

■ Valentina Krachmalnicoff (Institut Langevin, France)

392

"Nanoscale mapping of the local density of optical states in the near-field of a plasmonic antenna"

436

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Oral

Pag

■ Kristof Lodewijks (Chalmers University of Technology, Sweden) "Designer magnetoplasmonics in ferromagnetic nanoparticles through symmetry breaking"

438

■ Fernando López-Tejeira (Universidad de Zaragoza, Spain) "High Performance Nanosensors Based on Plasmonic Fano-Like Interference"

440

■ Beri N. Mbenkum (Centro Nacional de Microelectrónica (CSIC), Spain) "Size- & Shape-Independent Tuning of Plasmon Resonance Frequency of Sub 10 nm Gold Nanoparticles"

443

■ Vilianne Ntsame Guilengui (Institut d'Electronique du Sud, France) "Localized Surface Plasmons Resonances on GaSb-based materials for Infrared applications"

445

■ Olalla Pérez-González (University of the Basque Country, Spain) "Transport and Sensing in Plexcitonic Nanocavities"

447

■ Mohamed Ameen Poyli (Donostia International Physics Center (DIPC) and Centro de Fisica de Materiales, CFM(CSIC_UPV/EHU)., Spain) "Dielectric Gap-nanoantennas for Low-loss Field Enhanced Spectroscopy"

449

■ Juan Jose Saenz (Universidad Autonoma de Madrid, Spain) "Theoretical and experimental analysis of the directionality of the electromagnetic scattering by magnetodielectric small spherical particles"

452

■ Viktor Shalagatskyi (Institut des Molécules et Matériaux du Mans, France) "The nanostructured acoustic Fresnel lens for focusing THz phonons in gold"

454

■ Francisco Javier Valdivia-Valero (ICMM-CSIC, Spain) "Optical forces on cylinders near subwavelength slits illuminated by either a Gaussian beam or a photonic nanojet: effects of extraordinary transmission and excitation of Mie resonances"

456

■ Alan Vitrey (IMM-CSIC, Spain)

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459

393

"Near-field patterns in two dimensional arrays of gold nanorods supporting geometric resonances"

Index PPM2013 Contributions Alphabetical Order I:Invited / O: Oral

Pag

■ Javier Aizpurua (CFM/CSIC & DIPC, Spain) "The quantum regime in tunneling plasmonics"

I

399

O

400

O

402

O

404

O

405

I

407

O

408

I

410

O

411

O

413

O

415

I

-

O

416

O

418

O

420

O

422

I

424

■ Rodrigo Alcaraz de la Osa (University of Cantabria, Spain) "Quantum effects in small plasmonic particles in the UV-VIS range"

■ Pablo Alonso-González (CIC nanoGUNE, Spain) "Visualizing the near-field coupling and interference of bonding and anti-bonding modes in infrared dimer nanoantennas"

■ Hidehiko Asanuma (Max Planck Institute of Colloids and Interfaces, Germany) "Molecular self-assembly towards macroscale ordering: application as SERS substrate"

■ Alvaro Blanco (ICMM-CSIC, Spain) "Observation and use of internal water in silica photonic structures"

■ Remi Carminati (ESPCI, France) "Weak and strong coupling to photonic modes in nanoscale disordered media"

■ Alexandre Cazé (Institut Langevin ESPCI Paristech CNRS, France) "Cross Density of States and spatial coherence in complex plasmonic systems"

■ Alfonso Cebollada (IMM-CNM-CSIC, Spain) "Magnetoplasmonics: combining magnetic and plasmonic functionalities"

■ Alexander Chizhik (Universidad del País Vasco, Spain) "Mechanisms of magnetization reversal in magnetic wires. Magneto-optical study"

■ Eduardo Coutino Gonzalez (KULeuven, Belgium) "Luminescent zeolite composites with outstanding external quantum efficiency using silver clusters as dopants"

■ Nuno de Sousa (Universidad Autonoma de Madrid, Spain) "Theoretical study of the magneto-optical activity in Au/Co/Au disks"

■ Aristide Dogariu (Univ. of Central Florida, USA) “Optical Action in Complex Media”

■ Ruben Esteban (Centro de Fisica de Materiales, Centro Mixto CSIC-UPV/EHU and Donostia International Physics Center (DIPC), Spain) "Linear chains as optical building blocks of complex metallic clusters"

■ Josep Ferré i Borrull (Universitat Rovira i Virgili, Spain) "Simplified Method for 3D-structured Nanoporous Anodic Alumina with stop bands in the visible"

■ Luis S. Froufe-Perez (CSIC, Spain) "Wide band transparent metallo-dielectric nanowires at telecommunications wavelengths"

■ Juan Galisteo-López (ICMM-CSIC, Spain) "FRET-mediated amplified spontaneous emission in biopolymer complexes"

■ Francisco J. García-Vidal (UAM, Spain)

394

"Theory of strong coupling between quantum emitters and propagating surface plasmons"

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I:Invited / O: Oral

Pag

■ Manuel Gómez (CIQUS, Center for Research in Biological Chemistry and Molecular Materials, Spain) "New SERS substrates made of polymers and Al, cheap and highly efficient"

O

425

O

427

O

428

O

430

I

431

O

432

I

433

O

434

O

436

I

437

O

438

O

440

I

442

O

443

I

444

O

445

O

447

O

449

I

451

O

452

■ Jordi Gomis Bresco (Institut Català de Nanotechnologia (ICN), Spain) "Optomechanical coupling in 1D corrugated structures with complete dual photonic and phononic band gap"

■ Juan Bautista Gonzalez Diaz (CIC nanoGUNE, Spain) "Quantitative Magneto-Optical Characterization of Diffusive Reflected Light from Rough Steel Samples"

■ Marcin Grzelczak (Universidad de Vigo, Spain) "Optical response of individual Au-Ag@SiO2 hetero-dimers"

■ Rainer Hillenbrand (CIC nanoGUNE, Spain) "Infrared Near-field Spectroscopy - From Nanoscale Chemical Identification of Polymers to Real-space Imaging of Graphene Plasmons"

■ Magnus Jonsson (Delft University of Technology, Netherlands) "Nanopores for Bioanalytical Sensing"

■ Tobias Kippenberg (EPFL, Switzerland) "Cavity Optomechanics: Exploring the coupling of light and micro- and nanomechanical oscillators"

■ Oleksandr Kovalenko (Institut des Molécules et Matériaux du Mans, France) "Magnetization switching by ultrashort acoustic pulses"

■ Valentina Krachmalnicoff (Institut Langevin, France) "Nanoscale mapping of the local density of optical states in the near-field of a plasmonic antenna"

■ Philippe Lalane (IOGS, Palaiseau, France) "Purcell factor of photonic and plasmonic nanoantennas"

■ Kristof Lodewijks (Chalmers University of Technology, Sweden) "Designer magnetoplasmonics in ferromagnetic nanoparticles through symmetry breaking"

■ Fernando López-Tejeira (Universidad de Zaragoza, Spain) "High Performance Nanosensors Based on Plasmonic Fano-Like Interference"

■ Maciej Lorenc (IPR- UMR6251, Rennes, France) "Femtosecond Spin-State Photoswitching of Molecular Nanocrystals"

■ Beri N. Mbenkum (Centro Nacional de Microelectrónica (CSIC), Spain) "Size- & Shape-Independent Tuning of Plasmon Resonance Frequency of Sub 10 nm Gold Nanoparticles"

■ Lukas Novotny (ETH Zurich, Switzerland) "Cascaded Field Enhancement with Self-Similar Antennas"

■ Vilianne Ntsame Guilengui (Institut d'Electronique du Sud, France) "Localized Surface Plasmons Resonances on GaSb-based materials for Infrared applications"

■ Olalla Pérez-González (University of the Basque Country, Spain) "Transport and Sensing in Plexcitonic Nanocavities"

■ Mohamed Ameen Poyli (Donostia International Physics Center (DIPC) and Centro de Fisica de Materiales, CFM(CSIC_UPV/EHU)., Spain) "Dielectric Gap-nanoantennas for Low-loss Field Enhanced Spectroscopy"

■ Romain Quidant (ICFO, Spain) "Controlling the interaction of light with the very small"

■ Juan Jose Saenz (Universidad Autonoma de Madrid, Spain)

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395

"Theoretical and experimental analysis of the directionality of the electromagnetic scattering by magnetodielectric small spherical particles"

I:Invited / O: Oral

Pag

■ Anne Sentenac TBC (Institut Fresnel- UMR 7249, Marseille, France) "Improving the resolution of optical far-field microscopes using structured illumination"

I

453

O

454

O

456

I

458

O

459

I

461

I

-

I

462

■ Viktor Shalagatskyi (Institut des Molécules et Matériaux du Mans, France) "The nanostructured acoustic Fresnel lens for focusing THz phonons in gold"

■ Francisco Javier Valdivia-Valero (ICMM-CSIC, Spain) "Optical forces on cylinders near subwavelength slits illuminated by either a Gaussian beam or a photonic nanojet: effects of extraordinary transmission and excitation of Mie resonances"

■ Niek F. van Hulst (ICFO, Spain) "Non-dipolar & magnetic interactions with optical antennas"

■ Alan Vitrey (IMM-CSIC, Spain) "Near-field patterns in two dimensional arrays of gold nanorods supporting geometric resonances"

■ Martin Wegener (Karlsruhe Inst. of Technology, Germany) "Three-dimensional optical laser lithography: No limits?"

■ Diederik Wiersma (LENS, Italy) Abstrat not provided by the speaker

■ Anatoly Zayats (King's College London, UK)

396

"Active Nanoplasmonics: Loss, Gain and Nonlinearity"

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A b s t r a ct s Alphabetical order

PPM 2013

Invited

1

Material Physics Center CSIC-UPV/EHU and Donostia International Physics Center DIPC, Donostia-San Sebastián Spain, ruben_esteban@ehu.es, aizpurua@ehu.es.

2 Institut des Sciences Moléculaires d’Orsay - UMR 8214, CNRS-Université Paris Sud, Orsay Cedex, France.

3 Department of Physics,MS61, Laboratory for Nanophotonics, Rice University, Houston, Texas, USA 4 Nanophotonics Centre, Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom

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aizpurua@ehu.es

effects in plasmonic gaps at subnanometer separation distances [3]. The modelled structures (longer than 1 micrometer), exceed by several orders of magnitude the sizes typically tackled with TDDFT. Notably, the measured and calculated farfield spectra are in good agreement, which further emphasizes the relevance of the proposed method to correctly address experimental situations.

Moreover, our QCM simulations open the possibility to predict both the optimal near field enhancement and confinement expected a task that has still not been yet reported experimentally.

References [1] J. Zuloaga and P. Nordlander, Nano Lett. 9 (2009) 887.

[2] . Esteban, A. Borissov, P. Nordlander and J. Aizpurua, Nature Communications 3 (2012) 825.

[3] K.J. Savage, M.M. Hawkeye, R. Esteban, A.G. Borisov, J. Aizpurua and J.J. Baumberg, "Revealing the quantum regime in tunnelling plasmonics," Nature 491, (2012) 574.

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Electron transfer due to quantum tunnelling between two metallic structures strongly modifies the plasmonic resonances of the system. For small particles, the resulting optical behaviour can be studied using Time-Dependent Density Functional Theory (TDDFT) [1]. The particles used in typical plasmonics applications, however, often have dimensions that are tens, hundreds of even thousands of nanometers long, and thus they are too large to be treated with state-of-the-art TDDFT. Here, we present a Quantum Corrected Model (QCM) that includes the effect of quantum tunnelling in the calculation of the plasmonic response of large structures at subnanometer separation distances [2]. The model requires to define an effective material in the region where tunnelling is happening, with the properties of the material given by exact quantum calculations from a simplified system. A standard solver of Maxwell equations can then be used to obtain the response of the entire system. QCM is straightforward to implement for arbitrary geometries, which can exhibit narrow gaps or particles in contact.

We first test the QCM results against small Na spheres that can be also simulated using TDDFT, and find very good agreement between both methods. Next, we consider the case of large Drude-like Au structures to illustrate the effect of tunnelling in realistic plasmonic systems formed by large nanometric structures. As expected from previous work in small particles, we observe a spectral redistribution of the modes for all the geometries and a collapse of the near-field enhancement at very short separation distances..

We also consider the experimental situation of two approaching gold tips, a system which we have recently tested to experimentally reveal quantum

1

Javier Aizpurua 1 2 R. Esteban , A. G. Borisov 3 4 P. Nordlander , K. J. Savage M. M. Hawkeye4 and 4 J. J. Baumberg

PPM 2013

The quantum regime in tunneling plasmonics

Oral Quantum effects in small plasmonic particles in the UV-VIS range

Rodrigo Alcaraz de la Osa J. M. Sanz J. M. Saiz F. González and F. Moreno alcarazr@unican.es

Grupo de Óptica, Departamento de Física Aplicada. Universidad de Cantabria Avda. de Los Castros s/n, 39005 Santander, Spain

400

The remarkable growth of nanotechnology has been driven by the ability to alter material properties as dimensions are reduced towards the atomic scale. Nanomaterials exhibit physical and chemical properties very different from those of their bulk counterparts, often resulting from enhanced surface interactions or quantum confinement. Therefore, the plasmonic properties of particles in the quantum size regime (radii below 10 nm) have recently received a renewed attention [1], fueled by the race of technologies towards the low nano-scale domain. Our group has recently examined the plasmonic properties of silver and gold nanospheres and dimers, with radii ranging from 10 to 1nm, extending from the classically described regime to the quantum size regime [2]. As a summary, it can be said that the introduction of quantum mechanically (QM) corrected optical properties becomes in blueshifted [1] and weaker resonances [2]. As a consequence, a dramatic change in the interaction of dimers is observed, especially in the case of gold, where the introduction of QM corrected optical properties quenches the plasmonic resonance and predicts an absence of the expected associated redshift.

In response to an increasing demand to detect and recognize biological toxins [3], to enhance biological imaging and to characterize semiconductor devices at the nanometer scale [4] among other applications, interest in UV plasmonics is rapidly growing. In this work we present what we believe is the first study of quantum effects in small plasmonic particles in the UV-VIS range, comparing UV-candidate materials such as aluminum or gallium with silver and gold.

To model the optical properties of quantumsized plasmonic particles, a revised expression for the permittivity is required. In our analysis, the

standard Drude model is recast with Lorentzian terms that are defined quantum mechanically, based on fundamental physical phenomena, such as electron transition frequencies ωif and oscillator strengths S. The overall permittivity expression can then be described as follows [5] (1)

where εIB is a frequency-dependent correction term to account for the contribution of the d-band valence electrons to interband transitions at higher energies, ω is the plasma frequency and γ is the scattering frequency, dependent on the nanosphere dimension (particle radius) [1].

As an example, Figure 1 shows a color plot of the QM corrected relative electric permittivity (both real and imaginary parts) as a function of both the incident energy (resonance range) and the particle radius, comparing silver and aluminum. The black dots represent the resonance position (where Re{ε} = -2). The results indicate an increasingly substantial change in the nanoparticle permittivity, with a clear blueshift of the resonance as the radius is reduced below 5 nm.

Figure 2 shows the spectral (as a function of the incident wavelength) extinction efficiency for isolated spherical particles of radius R = 4nm made of silver and aluminum, calculated with both bulk and QMcorrected optical properties. The characteristic blueshift is observed in both cases, whereas the weakening of the resonance is much lower in the case of aluminum, in part due to the larger size parameter compared to that of the silver case.

In summary, in this research we will explore the consequences of introducing QM corrected optical properties when considering very small plasmonic

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particles in the UV-VIS range, paying special attention to the relative size as compared with the incident wavelength and its effects on their plasmonic properties (blueshifting [1] and weakening [2]).

Figures

References

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Figure 1: QM corrected relative electric permittivity (both real and imaginary parts) as a function of both the incident energy (resonance range) and the particle radius for silver and aluminum.

The black dots represent the resonance position (where Re{ε} = -2).

Figure 2: Spectral (as a function of λ) extinction efficiency for isolated spherical particles of radius R = 4nm made of silver and aluminum, calculated with both bulk and QM-corrected optical properties.

401

[1] J. A. Scholl, A. L. Koh, and J. A. Dionne, Nature, 483 (2012) 421.

[2] R. Alcaraz de la Osa, J. M. Sanz, J. M. Saiz, F. González, and F. Moreno, Optics Letters, 37 (2012) 5015-5017.

[3] I. Lieberman, G. Shemer, T. Fried, E. M. Kosower, and G. Markovich, Angewandte Chemie, 120 (2008) 4933.

[4] D. Cooper, F. de la Peña, A. Béché, J.-L. Rouvière, G. Servanton, R. Pantel, and P. Morin, Nano Letters, 11 (2011) 4585-4590.

[5] W. A. Kraus, and G. C. Schatz, J. Chem. Phys., 79 (1983) 6130.

PPM 2013

Acknowledgements: This research has been supported by MICINN under project FIS201021984. R. Alcaraz de la Osa also thanks the Ministry of Education of Spain for his FPU grant.

Oral Visualizing the near-field coupling and interference of bonding and antibonding modes in infrared dimer nanoantennas 1

CIC nanoGUNE Consolider, 20018 Donostia-San Sebastian, Spain Centro de Fisica de Materiales (CSIC-UPV/EHU) and Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain 3 I.N.T.I.– CONICET, Av. Gral. Paz 5445, Ed. 42, B1650JKA, San Martín, Bs As, Argentina 4 IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain

Pablo Alonso-González

1

P. Albella2, F. Golmar1,3 L. Arzubiaga1, F. Casanova1,4 L. E. Hueso1,4, J. Aizpurua2 and and R. Hillenbrand1,4

palonso@nanogune.eu

2

In this talk we will show the direct visualization and identification of capacitive coupling of infrared dimer antennas in the near field by employing scattering-type scanning near-field optical microscopy (sSNOM) [1]. The coupling is identified by (i) resolving the strongly enhanced nanolocalized near fields in the antenna gap (Figure 1) and by (ii) tracing the red shift of the dimer resonance when compared to the resonance of the single antenna constituents (Figure 2).

Furthermore, by modifying the illumination geometry we break the symmetry, providing a means to excite both the bonding and the “dark” antibonding modes. By spectrally matching both modes, their interference yields striking net enhancement or suppression of the near fields at specific locations, which could be useful in nanoscale coherent control applications.

Figures

References

402

[1] P.Alonso-González, P. Albella, F. Golmar, L. Arzubiaga, F.Casanova, L. E. Hueso, J. Aizpurua, and R. Hillenbrand. Optics Express, 21(1) (2013) 1270.

Figure 1: Experimental set-up and near-field imaging. (a) Illustration of the s-SNOM used for mapping the near-field distribution and topography of infrared dimers. The Si tip, which vibrates at the mechanical resonance frequency Ω of the AFM cantilever, is used to scatter the antenna fields. Using a parabolic mirror objective, the dimer is illuminated with the focused beam of a CO2 laser (Einc), which is polarized parallel to the long axis of the antennas (s-polarization). The same objective is used to collect the backscattered light (Eff). A polarizer in front of the detector ensures the selection of either s-polarized or p-polarized backscattered fields. Signal demodulation at higher harmonics nΩ in combination with a pseudo-heterodyne interferometric detection yields background-free near-field amplitude |En| and phase ϕn maps. (b) Topography and near-field images of a dimer antenna for (c) p-polarization (|E4|p, ϕ4p) and (d) s-polarization (|E4|s, ϕ4s) detection schemes. The imaging wavelength is λinc= 11.1 µm. The dashed white line in the phase images highlight the nanorods contour.

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PPM 2013

403

Figure 2: Verification of near-field coupling in dimer antennas. (a) Near-field amplitude |E4|s and (b) phase Ď&#x2022;4s images of dimer antennas with a varying length L. The horizontal white lines separate the images taken individually. (c) Comparison of the normalized near-field amplitude in dimer antennas (red dots) and single nanorods (blue dots) as a function of nanorod length L. (d) Comparison of the near-field phase Ď&#x2022;4s/2 in dimer antennas (red dots) and single nanorods (blue dots) as a function of nanorod length L. The crosses in the antenna schematics show the locations were the fields were evaluated: the center of the gap for the dimers and the nanorod extremity for the single nanorods.

Numerical calculations by FDTD of the in-plane component of the antennas´s near-field amplitude and phase are also shown in (c) and (d) by red (dimers) and blue (single nanorods) solid lines.

Oral Molecular self-assembly towards macroscale ordering: application as SERS substrate

Hidehiko Asanuma 1 H. MĂśhwald and 2 T. Nakanishi

1

Hidehiko.Asanuma@mpikg.mpg.de 1

Department of Interfaces, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany 2 Macromolecules Group, National Institute for Materials Science, Organic Nanomaterials Center, Tsukuba 305-0047, Japan

A â&#x20AC;&#x153;bottom-upâ&#x20AC;? approach to construct organized structure has been investigated immensely by scientists and engineers. Self-assembly has shown to fabricate numbers of different organized structures. Molecular self-assembly, however, has yet to exhibit ordered structure greater than micron; at greater scale, molecular interactions alone rarely translate into organized structure.

Here, we report a method where intermolecular forces among the molecules solely drive structural formation of highly organized three-dimensional structure at macroscopic scale. The method involves spreading solvated molecule at air-water interface. By tuning equilibrium and nonequilibrium conditions, intermolecular forces among the molecules solely can drive structural formation to organize at meso/microscopic scale.

Currently, the library of molecules that are capable to form such structures are expanding.

Furthermore, these mesoscopic structures were metalized and applied as a surface enhanced raman spectroscopy (SERS) substrate, Terahertz (THz) antenna, and for surface enhanced photochemistry.

404

Figure

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Oral Observation and use of internal water in silica photonic structures

Alvaro Blanco M. Morales F. Gallego-Gómez and C. López

ablanco@icmm.csic.es

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thermal annealing. By doing this we can acquire deep knowledge on silica chemistry and use it to tune the structure photonic response. Further, although thermal effects regarding the whole structure (sample size around some square centimeters) are usually rather slow (seconds) we can bring this response to the millisecond range by inducing local heating [7]. The opal was photoirradiated with a focused 488-nm Ar+-laser while measuring the opal reflectance spectrum in order to monitor in situ the PBG changes.

Photoirradiation significantly affected the spectrum of the infiltrated opal in a reversible fashion (Figure 2a). Under light exposure the Bragg peak shifted to shorter wavelengths (up to 13 nm) within a few milliseconds and rapidly shifted back to the original position after turning the light off (Figure 2). Simultaneously, the bandgap width decreased (up to 5%) during irradiation, also reversibly. Thus, the photoinduced PBG changes were fast and, without external stimulus, fully reversible, and the shift distance directly depended on the irradiation intensity I. Additionally, the overall performance was reproducible over millions of cycles. All these issues are greatly relevant for switching applications demanding not only spontaneous reverse effect but also accurate response and fidelity in a fast fashion.

References [1] F. Gallego-Gómez, A. Blanco, V. CanalejasTejero and C. López, Small 2011, 7, 1838.

[2] F. Gallego-Gómez, A. Blanco, and C. López, Langmuir 2012, 37, 13992.

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Recently, it has been shown that silica artificial opals possess a PBG controlable by simple heating on a hot plate [1]. Submicrometer silica spheres easily form high-quality face-centered-cubic (fcc) structures displaying a Bragg peak (the lowest energy PBG) in the visible range. Given the hydrophilic character of silica, these opals inherently contain a substantial amount of molecular water (as much as 8 wt.% in asgrown samples) physisorbed on the silanol groups at the spheres surface. This water is partially placed between the spheres forming necks, leading to a nonclose-packed arrangement, so that the opal lattice parameter directly depends on the amount of water. Thus, controlled desorption of this water upon moderate opal heating induced large effects in the opal photonic properties, mostly due to shrinking of the lattice parameter in up to ~ 12 nm.

Complete water removal (achieved at ~ 120 ºC) leads to a pronounced blueshift of the Bragg peak of 25 nm. PBG changes are reversible upon cooling down to room temperature (RT) by virtue of spontaneous water re-adsorption. By in situ measuring PBG behavior with temperature one can extract relevant fundamental knowledge regarding water morphology and adsorption in silica colloidal systems [2], [3]. Further, this internal water plays an important role in AzoMolecules photo-alignment [4] or in the mechanical properties of these systems [5].

Furthermore, we have recently succeeded in observing this water by standard electronic microscopy as shown in figure 1 [6].

Once the presence of water is characterized we are able to use it for different means. The amount of adsorbed water and its distribution can be controlled by modifying the chemistry of the silica surface, from hydrophilic to hydrophobic through

PPM 2013

Instituto de Ciencia de Ciencia de Materiales de Madrid ICMM-CSIC C/ Sor Juana Inés de la Cruz 3 28049 Madrid, Spain

[3] F. Gallego-Gómez, A. Blanco, and C. López, J. of Phys. Chem. C 2012, 116, 18222.

[4] F. Gallego-Gómez, A. Blanco, D. Gomayo, and C. López, Adv. Funct. Mater. 2011, 21, 4109.

[5] F. Gallego-Gómez, V. Morales-Flórez, A. Blanco, De la Rosa-Fox, N. and C. López, Nano Letters 2012, 12, 4920.

[6] A. Blanco, F. Gallego-Gómez, and C. López, (Submitted 2013).

[7] F. Gallego-Gómez, A. Blanco, and C. López, Adv. Mater. 2012, 24, 6204.

Figures

Figure 1: Field emission electron microscope image of water bridges connecting three silica spheres

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Figure 2: Temporal evolution of the Bragg peak position of infiltrated as-grown (black lines) and annealed (at 450, 525 and 600 0 C, orange, green and blue lines) opals. The laser was turned on/off 2 ms after beginning the measurement (denoted by the dashed lines). In all cases, the irradiated area S was 0.002 mm2 and the laser intensity I was 30 W cm-2.

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Invited Weak and strong coupling to photonic modes in nanoscale disordered media

Remi Carminati A. Cazé and R. Pierrat

remi.carminati@espci.fr

The interplay between multiple scattering, nearfield interactions and material resonances in disordered media leads to substantial changes in the photonic properties, compare to that of bulk materials. Changes in the local density of optical states (LDOS) influence spontaneous emission as well as absorption of light (weak coupling regime or Purcell effect). LDOS statistics can be used to probe the photonic modes from the inside, and reveals the substantial role of near-field interactions [1-3]. In the regime of Anderson localization in quasi-1D and 2D geometries, strong coupling can be reached [4,5]. We analyze the strong coupling regime based on exact numerical simulation, in perfect agreement with a coupledmode theory. The theory shows how concepts from cavity QED and from transport theory can be connected, providing simple tools to guide and analyze experiments.

PPM 2013

Institut Langevin, ESPCI ParisTech, CNRS 1 rue Jussieu, 75238 Paris Cedex 05, France

References

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407

[1] A. Cazé, R. Pierrat, R. Carminati, Phys. Rev. A 82, 043823 (2010).

[2] V. Krachmalnicoff, E. Castanié, Y. De Wilde and R. Carminati, Phys. Rev. Lett. 105, 183901 (2010).

[3] R. Sapienza, P. Bondareff, R. Pierrat, B. Habert, R. Carminati and N. F. van Hulst, Phys. Rev. Lett. 106,163902 (2011).

[4] H. Thyrrestrup, S. Smolka, L. Sapienza and P. Lodahl, Phys. Rev. Lett. 108, 113901 (2012).

[5] A. Cazé, R. Pierrat and R. Carminati, Strong coupling to two-dimensional Anderson localized modes, submitted (2013).

Oral Cross Density of States and spatial coherence in complex plasmonic systems

Alexandre Cazé R. Pierrat and R. Carminati alexandre.caze@espci.fr

Institut Langevin, ESPCI ParisTech, CNRS 1 rue Jussieu, 75238 Paris Cedex 05, France

The Local Density Of States (LDOS) is a fundamental quantity for the understanding of light-matter interaction. It can be accessed experimentally by measuring the spontaneous decay rate of a fluorescent emitter. A good picture to understand this connection is that the stronger the modes available at the emitter position, the faster the latter decays.

Theoretically, the LDOS can be defined independently of the mode structure, using the Green function G

In this theoretical and numerical work, we introduce a new quantity that we call Cross Density Of States (CDOS), defined by analogy with the LDOS as

408

Whereas the LDOS contains information on the average strength of the modes at one position r, the CDOS counts the average strength of all modes that coexist at both positions r and r’. As a consequence, the CDOS contains an information on the spatial coherence due to the mode structure. More precisely, it allows us to define rigorously an intrinsic coherence length at any point r of a complex structure.

To illustrate the interest of this new quantity, we have focused on the case of disordered semicontinuous gold films. These structures are known to support unconventional plasmon modes that, in particular, can localize optical energy in subwavelength areas (hot spots) [1]. It

has been previously shown experimentally in our group that light localization on these systems could be addressed considering the statistical properties of the local density of optical states (LDOS) [2]. A correlation between enhanced fluctuations of the LDOS near the percolation threshold of the film and a reduction of the spatial extent of plasmon modes has been established.

We have developed a numerical method based on the Lippmann-Schwinger equation that allows us to compute with no approximation the Green function in the near-field of three-dimensional disordered semi-continuous films.

Our calculations take into account polarization, retardation and near-field interactions. They give us access to both the LDOS and the CDOS in the near field of these films.

Our numerical results exhibit the same enhanced LDOS fluctuations as in experiments [3].

Moreover, we are able to compute CDOS maps and to observe rigorously an overall squeezing of the optical modes near the percolation threshold (Fig. 1) [4]. This clarifies a basic issue in plasmonics concerning the description of the optical properties of these films. This illustrates the relevance of the CDOS in the study of spatial coherence in photonics and plasmonics systems, and more generally in wave physics.

References [1] S. Grésillon et al. Phys. Rev. Lett. 82 (1999) 4520.

[2] V. Krachmalnicoff, E. Castanié, Y. De Wilde and R. Carminati, Phys. Rev. Lett. 105 (2012) 183901.

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[3] A. CazĂŠ, R. Pierrat and R. Carminati, Photon.

Nanostr. Fundam. Appl. 10 (2012) 339.

[4] A. CazĂŠ, R. Pierrat and R. Carminati, Photon.

Nanostr. Fundam. Appl. 10 (2012) 339.

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Figures

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409

Figure 1: (a,b) Two numerical realizations of disordered gold films, with respective filling fractions f=20% and f=50%; (c,d) LDOS maps at distance d=40nm over the top of films (a) and (b); (e,f) CDOS maps on the same areas with one spatial dependance r fixed at the center of the film. Both LDOS and CDOS maps are normalized by the LDOS in vacuum. Wavelength is 780nm.

Invited Magnetoplasmonics: combining magnetic and plasmonic functionalities.

IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC) Isaac Newton 8, PTM, E28760 Tres Cantos, Madrid, Spain

Nanosystems with combined magnetic and plasmonic functionalities have in recent years become an active topic of research [1]. By an adequate internal architecture of the constituting components, the magneto-optical activity of these systems can be largely increased due to the electromagnetic field enhancement associated with the plasmon resonance. Simultaneously, the magnetic functionality permits the control of the plasmonic properties by an external magnetic field, which allows the development of active plasmonic devices. Magnetoplasmonic structures find applications for example in gas and biosensing areas and in integrated photonic devices for telecommunications.

After an introductory review of the current understanding on this topic, I will make special emphasis on the phenomenology that metaldielectric magnetoplasmonic nanodisks present.

These systems may exhibit two modes [2] of magnetic and electric dipolar character due to the interaction between the disks, coupling to the incident light in a different way, and giving rise to regions with low and high optical extinction. In this scenario, the insertion of a ferromagnetic component inside the structure introduces magneto-optical activity in the system [3]. The effect that the diferent constituent parameters have on the optical and magneto-optical properties of these systems will be discussed in detail.

Alfonso Cebollada G. Armelles A. García Martín M.U. González D. Meneses-Rodríguez F.García and J.C.Banthí

alfonso@imm.cnm.csic.es

[3] J.C.Banthi et al., Advanced Materials, 24 (2012) OP36.

References

410

[1] G.Armelles et al., Advanced Optical Materials 1 (2013) 10.

[2] A.Dmitriev et al., Small 3 (2007) 294.

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Oral Mechanisms of magnetization reversal in magnetic wires. Magneto-optical study.

1

Alexander Chizhik 1,2 A. Zhukov and 1 J. Gonzalez

1

oleksandr.chyzhyk@ehu.es

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circular magnetic field HCIRC, an electric current flowing I through the wire has been used.

It was found 4 different mechanisms of the magnetization reversal depending on the configuration of external magnetic field (Fig. 1).

The increase of the DC circular magnetic field causes the change of the mechanism.

First, the magnetization reversal has been studied for the case of HCIRC = 0. The sample of Kerr image obtained for the magnetic field applied parallel to the wire is presented in Fig. 1 (a). This observation corresponds well to the found earlier long distance quick motion of the solitary circular domain walls (DW) related to giant Barkhausen jump.

It was found that the increase of the circular magnetic field causes the successive changes of the mechanism of the magnetization reversal.

Here we present 3 different types of this mechanism as a dependence of the value of HCIRC DC. The first change of the mechanism of the surface magnetization reversal takes place for the value of the HCIRC DC of 0.5 Oe: the effect of domain suppression is observed (Fig. 1(b)) - the advantageous dark CIRCS domain placed in the centre of the frame, disappears under the pressure of two moved domain walls marked by the red arrows in the figure. The specific feature which we consider as a key one is the periodical difference in the angle of the inclination of the domain walls: the left DW of the bright domains is more inclined toward the axial direction then the right DW. This difference results into a formation of wedge shaped domain with the tendency to instability and disappearance.

Subsequent growth of the HCIRC DC (up to 0.65 Oe) leads to a new modification of the magnetization reversal - the drift of the surface

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Sensors based on magnetic microwires have reached the competitive level in the area of micro-sensors [1]. Application of GMI effect in these sensors – the most promising effect discovered in glass covered microwires, is related mainly to the transformation of surface magnetic domain structure. Although the magnetic microwires have been studied widely during the last years the elucidation of the mechanisms of magnetization reversal is the actual task. The present work is devoted to the recent results on magneto-optical Kerr effect (MOKE) study of the surface magnetization reversal and surface domain structure in glass covered amorphous microwires.

Experiments have been performed in Co-rich microwires (metallic nucleus radius 50 µm, glass coating thickness 20 µm, and a ratio of metallic nucleus diameter to total microwire diameter ρ = 0.7). Magnetic domain imaging in the surface of microwires has been performed by means of optical polarizing microscopy in the longitudinal magneto-optical Kerr effect (L-MOKE) configuration [2]. The magnetic contrast of the domain structure was improved by standard image processing. The surface magnetic domains could be observed basically because of different in-plane (circular) components of the surface magnetization that transforms to black-white contrast when the polarized light reflects from the top of the cylindrically shaped surface of the microwire.

The incidence plane was perpendicular to the wire axis In the present study we put our attention mainly on the transformation of the surface domain structure. The experiments have been performed in crossed magnetic fields. The external magnetic field HΣ was a sum of an axial (HAX) and a circular (HCIRC) fields (Fig. 1). In order to produce the

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Departamento de Física de Materiales, Facultad de Química, Universidad del País Vasco, UPV/EHU, San Sebastián, Spain 2 IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain

domains is observed (Fig. 1(c)). The magnetization reversal occurs basically as the nucleation of multiple domains followed by the directed motion of the wedged domains as whole objects along the microwire. The moved domains reduce during the drift process up to the complete disappearance.

The last type of the mechanism of the magnetization reversal observed here is the formation and transformation of the vortex domain structure (Fig. 1(d)). The increase of the DC circular magnetic field (up to 1 Oe) causes the formation of the compact structure which could be qualified as a non-planar vortex-type structure. The domain structure observed under the present configuration of two magnetic fields is very unusual and never has been fixed earlier in magnetic microwires. At the first stage of the magnetization reversal this surface structure is characterized by the extended domain walls parallel to the wire axis.

The analysis of the obtained results has been performed based on our theoretical model supposed four magnetization states with different chirality [3]. Helical magnetic field induces the co-existence of stable and metastable helical magnetic states in the surface of the microwire. The variation of DC circular magnetic field causes the formation of complex magnetic multi-domain structure. When the circular field is high enough four different helical states co-exist forming the vortex structure. In turn, the axial magnetic field induces the transformation and rearrangement of the vortex structure.

Figure

Figure 1: Kerr image obtained for different configurations

of external magnetic field. (a) HCIRC DC = 0; (b) HCIRC DC = 0.5 Oe; (c) HCIRC DC = 0.65 Oe; HCIRC DC = 1 Oe.

References

412

[1] V. Zhukova, M. Ipatov and A. Zhukov, Sensors 9 (2009) 9216.

[2] J. Gonzalez, A. Chizhik, A. Zhukov and J. M. Blanco, Journal of Physics: A 208 (2011) 502.

[3] A. Chizhik, V. Zablotskii, A. Stupakiewicz, C. G贸mez-Polo, A. Maziewski, A. Zhukov, J. Gonzalez, and J. M. Blanco, Phys. Rev. B 82 (2010) 212401.

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Oral Luminescent zeolite composites with outstanding external quantum efficiency using silver clusters as dopants

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among the different types of silver clusters; most of the samples presented a high photo and chemo stability. Based on these results, silver containing zeolites were suggested to be used as potential phosphor substitutes for the fabrication of fluorescent lamps or as wavelength converters in solar cells because of their large stokes shift and luminescent performance. Next to price, the major decisive factor for such application is the external quantum efficiency (EQE). The EQE of a luminescent material is defined as the ratio of the amount of photons emitted to the amount of photons absorbed by a material, this measure takes into account losses associated with the absorption of photons by non-emissive species, like for instance in this case silver ions and impurities associated with the starting material.

The EQE parameter is of paramount importance to carefully select the luminescent materials for different applications. To the best of our knowledge there are no data available concerning the measurement of EQE of silver-clusters zeolite composites. One of the reasons for this lack of information on the luminescent of silver-clusters zeolite composites, is the difficulty of correctly measuring the EQE on highly scattering solid materials, especially when approaching the UV region for excitation.

Since the report published by de Mello and collaborators, in which an integrating sphere was used to measure the absolute EQE of thin dye doped films, many other studies were carried out to obtain the EQE of a wide range of solid samples showing the versatility of the method.

For instance, the EQE of fluorescent dye-loaded zeolites, fluorescent nanopigments incorporated in solid matrices, and polymer light emitting films have been reported using the integrating sphere

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Silver-zeolite composites are a versatile family of materials. Their applications range from catalysts, to antibacterial materials, information storage, and pressure or chemical sensors. The use of zeolites as molecular scaffolds for the fabrication of luminescent materials by incorporating transition metals has widely been explored. The creation of such oligoatomic metal clusters in zeolite voids is based on a ship-in-a-bottle approach, taking advantage of the high cation exchange capacity of zeolites. One of the most popular methods to produce metal clusters in zeolitic matrices is by exchanging the original charge-balancing cations present in the zeolites with the desired metal ions, followed by a thermal treatment. Small clusters are thus formed, whose size is ideally limited by the cage/pore dimensions of the zeolite topology.

The mechanism of cluster formation has been proposed as an â&#x20AC;&#x153;autoreductionâ&#x20AC;? mechanism, in which the electrons needed for metal ion reduction are provided by zeolite framework oxygen (resulting in local lattice damages) and/or by oxygen of the hydration water in the zeolite.

Alternatively, chemical reduction and photoactivation, have been employed for the creation of metal clusters and nanoparticles in zeolite matrices.

We recently reported the production of luminescent silver-clusters in zeolites. In this study, the effect of zeolite topology, silver loading, and counter-ion on the luminescence color, was systematically evaluated; green and red emitters were mainly found in LTA zeolite, while for FAU zeolite green and yellow emitters were observed. The photo-, chemo- and hydrostability of the materials were investigated in detail. The study revealed dramatic differences

eduardo.coutino@chem.kuleuven.be

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KULeuven Department of Chemistry Celestijnenlaan 200F, Leuven, Belgium

Eduardo Coutino-Gonzalez M. B. J. Roeffaers B. Dieu G. De Cremer B. Sels and J. Hofkens

method. Unlike the silver zeolites, most of the reported materials present a small stokes shift for which re-absorption problems are obviously expected. Furthermore, their optimal excitation wavelengths fall in the visible area, while the silver-clusters zeolite composites are mainly excitable by ultraviolet light. Remarkably, while all reports agreed on the usage of the integrating sphere, the set-up configuration and the methodology of the EQE experiments was sometimes different and often depending on the sample requirements. In order to obtain reliable results, it is critical to perform appropriate calibrations, taking into account the nature of the sample; thin film, loose powder, powder incorporated in a polymer, etc., and corrections for re-absorption processes.

We have measured for the first time the external quantum efficiency (EQE) of silver-clusters containing zeolites. These materials, fabricated by cation exchange followed by a thermal autoreduction process, have EQE's up to 69 percent.

Due to their unique spectral features such as large stokes shift and high EQE, these materials could be potentially used as phosphors for the fabrication of fluorescent lamps and as wavelength convertors in solar cells.

References

Figures

Figure 1: Emission-excitation 2D plots of two different luminescent silver-zeolite composites. Faujasite X zeolite with intermediate silver loading (top). Faujasite Y zeolite with intermediate silver loading (botton).

Figure 2 Schematic representation of the silver clusters contained in a sodalite cage (faujasite and LTA unit cage). Emission spectra of three luminescent silverzeolite composites upon UV excitation (right side up), and photographs under 366 nm irradiation with their respective EQE values (right side low).

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[1] Jacobs, P.; Uytterhoeven, J. J. Chem. Soc. Faraday T. 75 (1979) 56-64.

[2] Sun, T.; Seff, K. Chem. Rev. 94 (1994) 857870.

[3] de Mello, J.; Wittmann, H.; Friend, R. Adv. Mater. 9 (1997) 230-232.

[4] De Cremer, G.; Antoku, Y.; Roeffaers, M.; Sliwa, M.; Van Noyen, J.; Smout, S.; Hofkens, J.; De Vos, D.; Sels, B.; Vosch, T. Angew.

Chem. Int. Ed. 47 (2008) 2813-2816.

[5] De Cremer, G.; Coutino-Gonzalez, E.; Roeffaers, M.; Moens, B.; Ollevier, J.; Auweraer, M.; Schoonheydt, R.; Jacobs, P.; De Schryver, F.; Hofkens, J.; et al. J. Am. Chem. Soc. 131 (2009) 3049-3956.

[6] De Cremer, G.; Coutino-Gonzalez, E.; Roeffaers, M.; De Vos, D.; Hofkens, J.; Vosch, T.; Sels, B. ChemPhysChem 11 (2010) 16271631.

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Oral

1

Departmento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain 2 IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC), Isaac Newton 8, PTM E-28760 Tres Cantos, Madrid, Spain 3 Instituto de Estructura de la Materia, CSIC, Serrano 121 28006 Madrid, Spain

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1,

G. Armelles2 A. Cebollada2 F. García2 M. U. González2 D. Meneses-Rodríguez2 L. S. Froufe-Pérez3and A. García-Martín2

nuno.teixeira@uam.es

References [1] A. Dmitriev, T. Pakizeh, M. Käll, and D.S. Sutherland, Small 3, 294 (2007).

[2] J.C. Banthí et al., Adv. Mater. 24, OP36 (2012).

[3] P.J. Flatau, B.T. Draine, J. Opt. Soc. Am. A, 11, 1491 (1994).

Figure

Figure 1: Representation of the system modeled. Two gold disks separated a distance of z.

415

Metal/dielectric/metal plasmonic nanodiscs present a rich optical behaviour with the appearance of a bonding and an anti-bonding configuration that result in an electric- and a magnetic-dipole, respectively [1]. Due to symmetry considerations, the coupling of each configuration with the incident light differs, and the modes show a bright (electric dipole) or a dark (magnetic one) nature. The insertion of a ferromagnetic component in the structure introduces magneto-optical (MO) activity, and the presence of the MO response in both modes has been recently established, as well as the influence of the position of the ferromagnetic component [2].

So far, no attention has been paid to the differences in the MO response attending to the magnetic- or electric-dipolar character of each mode, neither to the influence of the coupling between the two metallic disks.

In this presentation we will show a theoretical model based on coupled dipole method [3], where we study the system above by considering each disk as a single dipole particle with an oblate geometry (fig. 1). The electromagnetic properties of the disks are described by an effective dielectric tensor, which incorporates the properties of the material constituents: gold for the plasmonic material and a ferromagnetic metal (cobalt) for the magneto-optically active one.

We will analyze the optical and magneto-optical response of that simple system as a function of the degree of interaction between the two dipoles. We will also explore the effect that the amount of ferromagnetic material present in the magneto-optically active ‘disk’ (mainly losses) has on these responses.

Nuno de Sousa

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Theoretical study of the magnetooptical activity in Au/Co/Au disks

Oral Linear chains as optical building blocks of complex metallic clusters 1

Centro de Fisica de Materiales, Centro Mixto CSIC-UPV/EHU and Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastiรกn, Spain 2 NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge, CB3 0HE, U.K. 3 Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge,Cambridge, CB2 1EW, U.K.

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Self-assembled clusters formed by metallic particles usually show clear plasmonic resonances, with hotspots characterized by very intense local fields [1]. These aggregates are of particular interest for surface enhanced Raman spectroscopy (SERS), which relies on the strong increase in the Raman signal emitted by a molecule when placed in a hot-spot. Here we study gold clusters glued by cucurbiturils, a macrocyclic molecule that acts as a linker between particles in the aggregate, setting the gap-distance between contiguous particles to approximately 1nm [2]. In contrast with other selfassembled systems, the interparticle distance is not only very small but it also presents relatively little variability between different gaps.

Furthermore, the cucurbiturils may also serve as a cage that captures a molecule under investigation at the positions between particles where the hot-spots are created. Such clusters show reliable and systematic optical properties and lead to clear Raman signals from gold particles of different sizes.

Clusters of metallic particles linked by cucurbiturils are thus a promising system for Raman spectroscopy of molecules. We focus our study on aggregates in solution presenting diffusion-limited growth and formed by gold spheres of fixed diameter, but other alternatives are possible. The diameter varies between clusters from 10 to 60 nm. We present experimental results of the optics of such clusters and interpret the phenomena observed using a simple model based on the optical activation of linear chains of particles within the cluster [3-6].

Notably, our experimental set-up allows for real time measurement of the extinction spectra and SERS signal, and thus for gaining information on

1

Ruben Esteban 2 R. W. Taylor 3 R. Coulston T. C. Lee3 2 S. Mahajan 3 O. A. Scherman 2 J. J. Baumberg 1 and J. Aizpurua

ruben_esteban@ehu.es

the dynamics of the aggregation process and how it affects the plasmonic response. In general, we observe a redshift of the lowest energy extinction peak that eventually reaches saturation. The exact results, however, depend on the diameter considered. Smaller particles lead to significantly weaker redshifts. Further, the number of particles in the cluster that optimizes the SERS signal also depends on the diameter of the spheres.

Our simulations [3-5,7-8] help to interpret the optical measurements. We consider complex clusters of up to 100 spheres, and observe how they support various resonances at different wavelengths, preferentially affecting different subunits of the full structure: at larger frequencies dimers and short chains modes are excited at the periphery of the cluster, while at larger wavelengths long chains modes are present, often located in the interior of the structure [4]. The measured and calculated extinction spectra are similar, which gives confidence on the validity of the particular simulations of aggregates to model the experimental situation. It is possible to identify in the spectra measured two different contributions [3] that can be associated with the dimers and long chains modes observed in the simulations.

These results supports the validity to model the optical response of the aggregate as that of a composite of linear chains of different length [4,5,9]. The description of the clusters in terms of simple chains does not only explain qualitatively the nature of the different modes supported by the structures, but it also allows for understanding the observed redshifts. Moreover, based in this description we have developed a simple semi-analytical composite dipole model

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[10] Z. B. Wang et al., J. Chem. Phys 128, (2008) 094705.

Figure

Figure 1: Displacement field D on a 2-dimensional aggregate of 100 spheres of 40nm diameter, illuminated by a plane wave at a wavelength of a) 645nm and b) 850nm. Strong fields extend over considerably longer chains for the larger wavelength, while they are mostly confined to dimers and small chains at the periphery of the aggregate for the larger energy. Logarithmic scale is used for the color scale.

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(CDM) [5] to gain information about the experimental clusters otherwise difficult to obtain. The CDM gives an effective length of the long chain modes and an effective proportion of spheres that contribute to this long chain resonance.

Last, we use the calculated behavior of straight chains to better understand the Raman measurements of complex clusters. When a fixed laser is used as excitation, both theory and experiments indicate that it is generally favorable for SERS to select structures of a particular size that results in the excitation of 2 the lowest energy mode by the illumination wavelength. The optimal size depends on the diameter of the spheres, due to the different redshifts pointed out above. More interesting from a theoretical perspective is the case when the excitation wavelength is not fixed, but can be tuned to maximize the Raman signal for a particular size of the structure and particle diameter. In this case, chain simulations show that there is still an optimal length [10] that depends on the diameter, with long chains being favorable for the smaller particles, and short chains or even dimers for the larger ones. We explain this observation by a simple model that considers a radiative correction, which significantly increases losses for long chains of large particles. This effect should also be important to explain the experimental optics of clusters.

References

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417

[1] M. I. Stockman et al., Phys. Rev. Lett. 72, (1994) 2486.

[2] Lee, T. C. and Scherman, O. A., Chem. Comm.

46, (2010) 2438.

[3] R. W. Taylor et al., ACS Nano 5, (2011) 3878.

[4] R. Esteban et al., Langmuir 28, (2012) 8881.

[5] R. W. Taylor et al., J. Phys. Chem. C 116, (2012) 25044.

[6] C. Girard et al., Phys. Rev. Lett. 97, (2006) 100801.

[7] F. J. GarcĂ­a de Abajo and A. Howie, Phys. Rev. B 65, (2002) 115418.

[8] T. Sannomiya et al., J. Comput. Theor.

Nanosci. 6, (2009) 749.

[9] N. Harris et al., J. Phys. Chem C 113, (2009) 2784.

Oral Simplified Method for 3D-structured Nanoporous Anodic Alumina with stop bands in the visible

Josep FerrÊ-Borrull M. Mahbubur Rahman J. Pallarès and L. F. Marsal

josep.ferre@urv.cat Universitat Rovira I Virgili Av. Paisos Catalans, 26 43007, Tarragona, Spain

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Nanoporous anodic alumina (NAA) is a material obtained by the electrochemical etching of aluminum in acid electrolytes with great interest in nanotechnology [1,2]. Its mechanical and structural properties and cost-effectiveness make NAA a first-choice candidate for several applications, such as in Biosensing [3,4] or Energy Harvesting [5,6]. When produced in the adequate conditions NAA shows a porous structure with a self-assembled pore distribution, what confers NAA a structure close to a Photonic Crystal: it consists of a 2-D triangular lattice of cylindrical parallel pores in an aluminum oxide matrix.

However, the periodicity is not perfect and natural self-assembled NAA shows symmetry breaking points that produce domains of random size (a few microns in characteristic length) and orientation. In this sense, we called such a structure quasi-random[7]. In this communication we show the development of a simplified method to modulate the pore geometry along its depth, and consequently to obtain a varying refractive index also in the direction parallel to the pores.

With this, NAA-based distributed Bragg reflectors (DBR) can be fabricated. This modulation of the refractive index contrast along the length of the pores can be used to obtain photonic crystal properties for all propagation directions along the material.

The method is based in our previous work[8] which shows that when a wet etching is applied to NAA to enlarge the pore diameter, the pore widening rate depends on the voltage applied in the anodization process. This result is depicted in Fig. 1, where the evolution of the refractive index of single-layer NAA with the pore widening time is plotted. The straight lines are only included as a guide-to-the eye. This result shows that the

refractive index for as-anodized samples is very similar if the applied voltage, but the refractive index contrast increases with the pore widening time.

This result enables the modulation of the pores by a slow variation of the anodization voltage as the one depicted in Fig. 2, followed by an additional pore widening step that contributes to the enhance these pore modulations. Figs. 2b,c show FESEM cross-sectional pictures of two samples produced with a cyclic voltage as shown in Fig. 2a. The cycles can be clearly distinguished, and their length can be controlled precisely by the amount of charge spent in the phase at which the voltage is maximum and constant. Even though the images in Fig. 2b,c correspond to asanodized samples, a clear pore modulation can be observed with a conical shape (a) and the beginning of pore branchings (b), corresponding to the lowest voltage within a cycle.

Fig. 3 shows the evolution with the pore widening time of the transmittance spectra of NAA DBR in samples produced after 150 cycles. The firstorder stop band shifts to lower wavelengths for increasing pore widening times and becomes deeper. The pore widening has also the effect of increasing the transmission losses for the shorter wavelengths. This stop band dependence can be related to the morphology of the pores. It has to be remarked that the stop bands in the visible range may have possible application in low-cost biosensors.

Acknowledgements This work was supported by projects CONSOLIDER HOPE project CSD2007-00007, AGAUR 2009 SGR 549 and TEC2012-34397. The

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authors thank the group CRNE of the Universitat Politècnica de Catalunya for the FE-SEM pictures

[1] Ingham, C. J., ter Maat, J., de Vos, W. M., Biotechnology Advances, 30 (2012) 1089.

[2] Lee, W., Schwirn, K., Steinhart, M., Pippel, E., Scholz, R., Gösele, U., Nature Nanotechnology, 3 (2008) 234.

[3] Nicolini, C.; Bragazzi, N.; Pechkova E., Advanced Drug Delivery Reviews, 64 (2012) 1522.

[4] de la Escosura-Muñiz, A and Merkoçi, A, ACS Nano, 6 (2012) 7556.

[5] Haberkorn, N; Lechmann, M.C.; Sohn, B. H.; Char, K; Gutmann, J. S.; Theato, P.; Macromolecular Rapid Communications, 30 (2009) 1146.

[6] Santos, A.; Formentín, P.; Pallarés, J.; FerréBorrull, J.; Marsal, L.F., Solar Energy Materials and Solar Cells, 94 (2010) 1247.

[7] Maksymov, I.; Ferré-Borrull, J.; Pallarès, J.; Marsal, L. F., Photonics and Nanostructures, Fundamentals and Applications, 10 (2012) 459.

[8] Rahman, M. M.; Garcia-Caurel, E.; Santos, A.; Marsal, L. F.; Pallarès, J.; Ferré-Borrull, J., Nanoscale Research Letters, 7 (2012) 474.

Figures

Figure 2: a) Applied voltage-time and registered current time curves for the first three cycles used to obtain NAA-based DBRs. b) and c) FE-SEM cross-sectional pictures of two different samples obtained with a different amount of charge spent in the constant 50V phase of each cycle.

1.6 1.5 1.4 1.3 1.2 0

20 V 30 V 40 V 50 V

2 4 6 8 Pore Widening Time (min)

10

Figure 1: Refractive index of NAA single layers produced with different anodization voltages as a function of the pore widening time.

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Figure 3: Transmittance spectra of NAA-based DBR for different pore widening times.

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Refractive Index

1.7

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References

Oral Luis S. Froufe-Pérez 1 R. Paniagua-Domínguez 1 D. R. Abujetas J. J. Sáenz2and 1 J. A. Sánchez-Gil

1

l.froufe@csic.es

Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Científicas, Serrano 121, 28006 Madrid, Spain.

2 Condensed Matter Physics Dept. and Centro de Investigación en Física de la Materia Condensada (IFIMAC), Universidad Autónoma de Madrid, Fco. Tomás y Valiente 7, 28049-Madrid, Spain.

Since several decades ago, different systems showing small light scattering efficiency has been proposed [1,2]. More recently, several nanometer sized structures have been studied and, even, experimentally demonstrated [3-7].

Those systems are based on the interaction of the electromagnetic modes in core-shell submicron sized particles. Even with relatively simple geometries, such as spherical or cylindrical coreshell structures, the degrees of freedom provided by size, available realistic materials and core-toshell size ratios, are enough to obtain a global optical response with prescribed properties in a given frequency range.

Optically invisible metamaterial fibers [3], multishell cylindrical cloaking devices [4], metal coated dielectric invisible cylinders [5] or ZnO/Ag nanowire composites [6] have been recently proposed as cylindrical devices showing certain cloaking properties, or combining high transparency -low scattering- with other properties such as high electrical conductivity.

One of the characteristics usually shared by many of the proposed systems is the resonant nature of the effect responsible for the transparency that, along with chromatic dispersion and absorption, lead to a narrowing of the transparency window.

In this work, we analyze in detail the conditions required to obtain small scattering efficiency in a coreshell cylinder for any metal or dielectric combination in the infrared at bands relevant to telecommunications. By the use of a simple model based on the quasi-static approximation with radiative corrections to the polarizability of a core-shell cylinder [8], we obtain general properties required to achieve transparency in realistic structures [9]. We also check our

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Wide band transparent metallo dielectric nanowires at telecommunications wavelengths

predictions against a more accurate model based on Mie theory for cylinders [10].

We find that, under rather general conditions, metal nanowires with high refractive index coating can show a transparency region which is more robust against fabrication defects (size polydispersity) than metal coated fibers. Also, it is shown that it is possible to obtain up to three orders of magnitude lower scattering efficiency ,compared with raw metal cylinders, in a band as wide as 20% of the central frequency, and with realistic materials (Si coated Ag wires) in the infrared (See figure 1). The transparency condition is also quite robust regarding the angle of incidence and polarization of the incoming signal [9].

It is shown that the near field scattering is extremely weak in the transparency region.

Hence, the coupling through evanescent modes among equal cylinders is essentially negligible.

Then, a high density assembly of appropriately designed nanowires present a extremely low scattering efficiency [9]. Even the wavefronts are negligibly disturbed in a random and high density assembly of transparent nanowires.

Acknowledgements Spanish “Ministerio de Economía y Competitividad” (CSD2008-00066, CSD200700046, FIS2009-11264, FIS2009-13430, FIS2012-36113 and FIS2012-31070), “Comunidad de Madrid” (S2009/TIC-1476), and European Social Fund (CSIC JAE-Pre and JAE-Doc grants).

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References

Figure 1: Approximate scattering efficiency Qscat as obtained from the quasi-static approximation. TM polarization (dashed line), TE polarization (dotted line) and unpolarized (continuous line) radiation is considered for both Ag@Si (black curves) and Si@Ag (red curves) structures. In a) Qscat at a constant wavelength λ=1550 nm is plotted as a function of the core to shell radii ratio.

In b), the spectra for the different polarization are presented. The ratio Rc/Rs is fixed in such a way that Qscat is minimized in TM polarization for each structure. In the inset c), the core radius is reduced by 5%.

421

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Figures [1] H. Chew and M. Kerker, Journal of the Optical Society of America 5 (1976) 445.

[2] M. Kerker, Journal of the Optical Society of America 65, (1975) 376.

[3] A. Tuniz, B. T. Kuhlmey, P. Y. Chen, and S. C. Fleming, Optics express 18 (2010) 18095.

[4] P. Mundru, V. Pappakrishnan, and D. Genov, Physical Review B 85 (2012) 045402. (3).

[5] P. Fan, U. K. Chettiar, L. Cao, F. Afshinmanesh, N. Engheta, an d M. L. Brongersma, Nature Photonics, 6 (2012) 380.

[6] Areum Kim, Yulim Won, Kyoohee Woo, ChulHong Kim, and Jooho Moon, ACS Nano, DOI 10.1021/nn305491x, January 21, 2013 (Web).

[7] R. Paniagua-Domínguez, F. López-Tejeira, R. Marqués, and J. A.Sánchez-Gil, New Journal of Physics 13 (2011) 123017.

[8] S. Albaladejo, R. Gómez-Medina, L. S. FroufePérez, H. Marinchio, R. Carminati, J. F. Torrado, G. Armelles, A. García-Martín, and J. J. Sáenz, Optics Express 18 (2010) 118710.

[9] L.S. Froufe-Pérez, R. Paniagua-Domínguez, D. R. Abujetas, J. J. Sáenz, and J. A. Sánchez-Gil, preprint.

[10] C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles (John Wiley &Sons, New York, 1998).

Oral FRET-mediated amplified spontaneous emission in biopolymer complexes

Juan F. Galisteo-L贸pez M. Ibisate V. Esteso and C. L贸pez

Instituto de Ciencia de Materiales de Madrid (CSIC) C/ Sor Juana In茅s de la Cruz 3, Cantoblanco 28049 Madrid, Spain

galisteo@icmm.csic.es

422

F枚rster resonance energy transfer (FRET), a longrange dipole-dipole interaction through which energy can be transferred between two chromophores separated by distances in the nanometer range, is becoming increasingly relevant in the field of photonics. Recently it has been shown how one can profit from such transfer mechanism in order to i.e. increase the efficiency of organic LEDs [1] or lasers [2].

Due to the nanometer sensitivity of FRET, materials presenting an intrinsic nanoscale structuration are commonly used as hosts to impose a chromophore distribution which can favor the efficiency of the FRET process. Some examples are zeolites, polymer blends or DNA. The latter, a biopolymer rapidly gaining attention in the field of photonics,[3] has been long studied in relation with FRET in both directions: using FRET as a means to detect structural changes in DNA and profiting from its natural scaffold to improve or control the transfer process. Recently DNA-lipid complexes [4,5] have been proposed as an environment where efficient FRET can be achieved by controlling the donor-acceptor concentration ratio [6]. These complexes are extremely attractive from the point of view of applications in photonics as they are soluble in organic solvents, represent a cost-effective approach and can be cast in the form of a polymer allowing the preparation of thin films, fibers, etc. To date, the feasibility of triggering two or even three-step FRET process [7] has been demonstrated in this polymeric matrices but a precise understanding of the transfer process is lacking. Further, its potential as FRET-based gain media has not been explored so far. Crucial to improving current and developing new applications for this system is a detailed knowledge of the FRET mechanism.

In this work we unveil the statistics of FRET in the above mentioned solid state biopolymer matrices. Tracking the dynamics of a population of donor molecules D (Coumarin 480) as acceptor ones A (DMASMPI) are added we find that rather than a single transfer process, a distribution of transfer processes (see Figure 1) has to be considered and an effective efficiency introduced.

Additionally, the occurrence of amplified spontaneous emission (ASE) is demonstrated and the possibility of controlling it with the FRET efficiency is assessed (see Figure 2) enabling DNA-lipid complex lasers.

References [1] M.A. Baldo, M.E. Thompson, S.R. Forrest, Nature 403 (2000), 750.

[2] M. Berggren, A. Dodabalapur, R.E. Slusher, Z. Bao, Nature 389 (1997) 466.

[3] A.J. Steckl, Nature Phot. 1 (2007) 3.

[4] K. Tanaka, Y. Okahata, J. Am. Chem. Soc. 118 (1996) 10679.

[5] L. Wang, J. Yoshida, N. Ogata, Chem. Mater.

13 (2001) 1273.

[6] Y. Ner, J. G. Grote, J. A. Stuart, G. A. Sotzing, Angw. Chem. Int. Ed. 48 (2009) 5134.

[7] D. Navarethne, Y. Ner, J. G. Grote, G. A Sotzing, Chem. Comm. 47 (2011) 12125.

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Figures

Figure 1: (a) PL decay curves for DNA-CTMA films with different ratios of D and A: 100:1 (grey curve) and 50:1, 25:1, 10:1 and 5:1 (black lines, arrow indicates decreasing values). (b) Decay curve for a sample having a 25:1 ratio (grey line) and a fit with a lognormal distribution of decay rates (black line). (c) Residual of the above fit.

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Figure 2: ASE threshold for DMASMPI emission (solid circles) and FRET efficiency (open circles) as a function of D/A concentration ratio.

Invited Theory of strong coupling between quantum emitters and propagating surface plasmons

Francisco J. García-Vidal

fj.garcia@uam.es

Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid 28049 (Spain)

In this talk we present the theoretical foundation of the strong coupling phenomenon between quantum emitters and propagating surface plasmons observed in two-dimensional metal surfaces [1]. For that purpose, we develop a quantum framework that accounts for the coherent coupling between emitters and surface plasmons and incorporates the presence of dissipation and dephasing. Our formalism is able to reveal the key physical mechanisms that explain the reported phenomenology and also to determine the physical parameters that optimize the strong coupling. A discussion regarding the classical or quantum nature of this phenomenon is also presented

References

424

[1] A. González-Tudela, P.A. Huidobro, L. MartínMoreno, C. Tejedor and F.J. García-Vidal, Phys.

Rev. Lett. 110, 126801 (2013).

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Oral New SERS substrates made of polymers and Al, cheap and highly efficient

Manuel G贸mez M. Lazzari

x.gomez@usc.es

ImagineNano2013

The experiments show an uniform SERS enhancement of several orders of magnitude over the structured substrates when tested with organic analytes like Rhodamine 6G, Coumarin 440 or Rhodamine B, using a excitation laser of 785nm working at 1 or 0.1mW . The signal enhancement is comparable or higher than that obtained with commercial substrates.

Aluminum coated substrates with comparable or even better enhancement of signal respect to the same substrates made of gold reduces even more the cost of these substrates. Additionally no change in the intensity of the spectra was observed after a month of storage at room conditions.

With this simple, fast and versatile molding process, it is possible to produce polymer SERS substrates with extremely low cost, high throughput, and in a highly repeatable way.

References [1] E.C. Le Ru, E. Blackie, M.Meyer, and P.G. Etchegoin, J.Phys. Chem. 111 (2007), 1379413803.

[2] F. Gentile , G. Das , M. L. Coluccio , F. Mecarini , A. Accardo ,L. Tirinato , R. Tallerico , G. Cojoc , C. Liberale , P. Candeloro ,P. Decuzzi , F. De Angelis , E. Di Fabrizio , Microelectron. Eng. 87 (2010), 798.

[3] B. Xu, Y. Zhang, W. Zhang, X. Liu, J. Wang, X. Zhang, D. Zhang H. Jiang, R. Zhang and H. Sun, Adv. Opt. Mat. 1, (2013), 56-60.

[4] M. G贸mez and M. Lazzari, Microelectronic Engineering,97, (2012), 208-211.

425

Raman signals are inherently weak, so a low number of scattered photons are available for detection; Surface Enhanced Raman Scattering (SERS) is a useful method to amplify weak Raman signals by an increment of the apparent Raman cross-section [1].

SERS uses nanoparticles or structured metal surfaces typically made of noble metals, commonly gold (Au) or silver (Ag). Laser excitation of these metal nanostructures resonantly drives the metal surface charges creating highly localized plasmonic light fields at these photonic structures, which we know as hotspots. When a molecule is bonded, adsorbed or lies close to the enhanced field of a hot-spot at the surface, a large enhancement in the Raman signal can be observed, -usually of several orders of magnitude- thereby making it possible to detect concentrations as low as 1018M of target molecules [2].

The main problem to use SERS as everyday lab technique is the lack of appropriate substrates.

The number of available commercial substrates is scarce and they are expensive and quite unstable, requiring to keep them in controlled atmospheres and a careful handling to maintain their enhanced properties. Important research efforts try to provide cheap and reliable substrates [3] In this work we show our results testing homemade SERS substrates based in an easy and cheap fabrication process comprising just two steps: a replica molding based on a UV-NIL like process, and coating of a thin layer of metal (Au, Ag), Al, or Ir by sputtering with Ar plasma or coated by PVD. As supporting material we choose a crosslinkable tetrafuntional perfluoropolyether derivate [4], and a commercial ormocer photoresist.

PPM 2013

CIQUS, Center for Research in Biological Chemistry and Molecular Materials Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain

Figures

426

Coumarin 440 Substrate: Structured PFPE +Al

ImagineNano2013

Oral

Optomechanical coupling in 1D corrugated structures with complete dual photonic and phononic band gap.

1

Jordi Gomis-Bresco

D. Navarro-Urrios1, M. Oudich2 A. Griol3, D. Puerto3 A. Martínez3, S. El-Jallal2 Y. Pennec2, B. Djafari-Rouhani2 F. Alzina1 and C. M. Sotomayor Torres1, 4, 5

1

Catalan Institute of Nanotechnology (ICN), 08193 Bellaterra, Spain.

IEMN, Universite de Lille 1, Villeneuve d’Ascq, France Nanophotonics Technology Center, Univ. Politecnica de Valencia, Valencia, Spain 4 Dept. of Physics, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain.

5 Catalan Inst. for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain.

2

jordi.gomis@icn.cat

Simultaneous confinement of photons and phonons in a tailored structure leads to a strong interaction between light and mechanical motion, allowing optomechanical effects, i.e., transduction of motion through optical signals and even direct actuation through energy transfer from light to phonons (heating, regenerative oscillations) or vice versa (cooling). The observation of such effects is limited to high quality factor photonic structures, and in photonic crystal cavities requires a careful design of the defect. We present the design and experimental characterization of suspended silicon one-dimensional corrugated nanobeams. We start from a unit cell that has simultaneously large and complete photonic and phononic band gaps1 and we chose parabolic variation of the period, the wing width and the hole radius to obtain highquality-factor cavities. By means of the evanescent field out of tapered fibre, we coupled light into the proposed cavities and identify several photonic resonances with Q factors in the range of 104.

Performing RF spectroscopy, spectral analysis of the time domain transmitted and re-coupled light, we identified several phononic modes ranging from tenths of MHz (clamping modes) to 7 GHz (confined modes).

Figures

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3

Figure 1: SEM image of a fabricated structure.

Figure 2: a) Photonic characterization of the structure b) RF spectroscopy of the different phononic modes.

References

ImagineNano2013

427

[1] Pennec, Y. et al. Band gaps and cavity modes in dual phononic and photonic strip waveguides. AIP Advances 1, 041901 (2011).

Oral Quantitative Magneto-Optical Characterization of Diffusive Reflected Light from Rough Steel Samples

Juan Bautista Gonzalez Diaz 1 J.A. Arregi 1 D. R. Abujetas A. Martínez-de-Guerenu 2 2 F. Arizti and 1 A. Berger

1

j.gonzalez@nanogune.eu 1

CIC nanoGUNE Consolider, Tolosa Hiribidea 76, E-20018 Donostia-San Sebastián, Spain 2 CEIT, Manuel de Lardizábal 15, E-20018 Donostia-San Sebastián, Spain

428

Magneto-Optical Kerr Effect (MOKE) magnetometry, spectroscopy and ellipsometry has been employed to characterize and study magnetic systems with different types of surfaces including rough ones [1-6], where it has been shown that there is an important relation in between surface roughness on one hand and domain size and magnetization reversal on the other [1-2,4]. The study of this kind of surfaces is of great importance to achieve a better understanding of the macroscopic magnetic response that arises from complex surfaces and its application to all types of devices. However, up to now, all magnetic optical studies have focused on surfaces where two fundamental characterization parameters, namely average roughness Ra and mean peak spacing RS, are small in comparison to the wavelength of light [16]. To our knowledge, no study has analyzed the magneto-optical response in other roughness regimes, i.e., magnetic surfaces with roughness parameters of the order (or much larger) than the wavelength of light, that makes the reflected light show a diffusely broadened spot. The only exception, being a very special particular case of roughness, is the study of the magneto-optical response of diffracted beams, in which the surface presents periodic variations [7,8]. This lack of studies may be attributed to the fact that diffuse light is not only very difficult to measure but also to interpret for generalized geometries, since the measurements usually depend on the spot size collected at the photo-detector as well as on the different optical and magneto-optical responses that occur at different scattering angles [7,8].

Such an analysis of samples with significant roughness would be useful from an applied and industrial point of view, since it may allow a low-

cost non-invasive surface magnetic characterization of industrial samples. The purpose of our study is therefore to explore this possibility. Specifically, we measure here the magneto-optical response of polished industrial samples of varying average roughness R, which is of the order of the light wavelength and has a mean peak spacing RS that is much larger than the observation wavelength (see figure 1). For this purpose, we performed quantitative MOKE measurements for diffusely scattered light with high signal-to-noise ratio, using a crossed polarizer setup that is conventionally utilized for MOKE and generalized magneto-optical (GME) ellipsometry. Our study demonstrates that for these specific samples, the magneto-optical activity is monotonously increasing as a function of the scattering angle, while preserving its field dependent shape, i.e. the hysteresis loop shape (see figure 2). We furthermore find that this behavior can be explained by considering the diffused light reflected from a rough surface to be equivalent to the reflection of light m from planar surface segments with varying incidence angles.

Finally, these results allow for scatter ing angle dependent integration and therefore, we expect that quantitative magneto-optical characterization of rough surfaces will find widespread applications for industrial samples.

References [1] M. Li, G.C. Wang, and H.G. Min, J. App. Phys.

83, 5313 (1998).

[2] Y.-P. Zhao, R. M. Gamache, G. C. Wang, T.M. Lu, G. Palasantzas and J.Th.M. De Hosson, J. Appl. Phys. 89, 1325 (2001).

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[3] P. Vavassori, L. Callegaro, E. Puppin, F. Malizia, and F. Ronconi, J. Mag. Mag. Mater.

157, 171 (1996).

[4] H.S. Nagaraja, K.K. Nagaraja, and F. Rossignol, J. Supercond. Nov. Magn. 25, 1901 (2012).

[5] J. Swerts, S. Vandezande, K. Temst, and C. Van Haesendonck, Solid State Commun. 131, 359 (2004).

[6] K. Zhang, M. Uhrmacher, H. Hofsäss, and J. Krauser, J. Appl. Phys. 103, 083507 (2008).

[7] T. Verduci, C. Rufo, A. Berger, V. Metlushko, B. Illic, and P. Vavassori, App. Phys. Lett. 99, 092501 (2011).

[8] M. Grimsditch and P. Vavassori, J. Phys.

Condens. Matter 16, R275 (2004).

Figures

Figure 1 Light microscopy images of the different samples employed in this study. For the sake of roughness comparison, all sample stripes are aligned vertically. The scale shown in (a) applies to all pictures. Below the images, we show the scattered laser spots corresponding to each of the samples. â&#x2C6;&#x2020; accounts for the difference in between incidence and scattering angles (â&#x2C6;&#x2020; = 0 for specular reflection)

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Figure 2 Experimentally determined Kerr rotation hysteresis loops for different scattering angles: (a-g) sample S1 with small roughness; (h-n) sample S3 with larger roughness. For comparison, figure (a) also displays the normalized bulk magnetization response of sample S1 (which is equivalent for all samples in our study) as a function of the applied magnetic field.

Oral Marcin P. Grzelczak1

Optical response of individual AuAg@SiO2 hetero-dimers 1

Departamento de Química Física, Universidade de Vigo, 36310 Vigo, Spain.

FemtoNanoOptics group, Université Lyon 1, CNRS, Institut Lumière Matière, 43 Bd du 11 Novembre, 69622 Villeurbanne, Fr 3 Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia- San Sebastián, Spain 4 Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain 2

The optical response and local field enhancement effect associated to the Localized Surface Plasmon Resonance (LSPR) of metal nanostructures have been extensively investigated, both experimentally and theoretically, during the last decade. Though the LSPR spectral position, amplitude and light polarization dependence can be modified for specific applications through tuning the nanoobject size, shape and composition [1-2]. This provide additional features not observed using objects formed by a single particle. The optical extinction response of individual Au-Ag@SiO2 hetero-dimers is investigated using spatial modulation spectroscopy and compared to numerical simulations using the dimer morphology determined by transmission electron microscopy (TEM). The extinction spectra show two resonances spectrally close to the surface plasmon resonances of the constituting Au and Ag@SiO2 core-shell particles. The inter-particle electromagnetic coupling is demonstrated to induce a large increase of the optical extinction of the dimer around its Au-like surface plasmon resonance for light polarized along its axis, as compared to that for perpendicular polarization and to that of an isolated Au nanoparticle [3].

A. Lombardi2 A. Crut2 P. Maioli2 I. Pastoriza- Santos1 L. M. Liz-Marzán3,4 N. Del Fatti2 and F. Vallée2

marcin@uvigo.es

[2] Liz-Marzán, L. Tailoring surface plasmons through the morphology and assembly of metal nanoparticles. Langmuir 2006, 32–41.

[3] Anna Lombardi, Marcin P. Grzelczak, Aurélien Crut, Paolo Maioli, Isabel Pastoriza-Santos, Luis M. Liz-Marzán, Natalia Del Fatti and Fabrice Vallée. Optical response of individual Au-Ag@SiO2 hetero-dimers. ACS Nano 2013, accepted.

References

430

[1] Kelly, K.; Coronado, E.; Lin Lin Zhao and George C. Schatz. The optical properties of metal nanoparticles: the influence of size, shape, and dielectric environment. The journal of physical chemistry B 2003, 107, 668–677.

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Invited Infrared Near-field Spectroscopy From Nanoscale Chemical Identification of Polymers to Real space Imaging of Graphene Plasmons

Rainer Hillenbrand

r.hillenbrand@nanogune.eu

During the last years, near-field microscopy based on elastic light scattering from atomic force microscope tips (scattering-type scanning nearfield optical microscopy, s-SNOM [1]) has become a powerful tool for nanoscale optical imaging and spectroscopy. Acting as infrared antennas, the tips convert the illuminating light into strongly concentrated near fields at the tip apex (nanofocus), which provides a means for localized excitation of molecule vibrations, plasmons or phonons in the sample surface. Recording the tipscattered light subsequently yields nanoscaleresolved infrared images, beating the diffraction limit more than two orders of magnitude.

Using broadband IR illumination and Fouriertransform spectroscopy of the tip-scattered light [2,3], we are able to record IR spectra with 20 nm spatial resolution (nano-FTIR). Particularly, we demonstrate that nano-FTIR can acquire near-field absorption spectra of molecular vibrations throughout the mid-infrared fingerprint region, allowing for chemical mapping and identification of polymer and protein nanostructures [3]. s-SNOM also enables the launching and detecting of propagating and localized plasmons in graphene nanostructures. Spectroscopic real-space images of the plasmon modes allow for direct measurement of the ultrashort plasmon wavelength and for visualizing plasmon control by gating the graphene structures [4.5].

[5] Z. Fei, et al., Nature 487, 82 (2012).

Figures

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CIC nanoGUNE Consolider, San Sebastian, Spain Ikerbasque, Basque Science Foundation, Bilbao, Spain

Figure 1 Figure: Optical nanoimaging of graphene plasmons. Upper panel: Sketch of the imaging method. A laser illuminated scanning tip launches plasmons on graphene. Detection is by recording the light backscattered from the tip. Lower panel: Optical image of graphene, where the fringes visualize the interference of the graphene plasmons.

References

ImagineNano2013

431

[1] F. Keilmann, R. Hillenbrand, Phil. Trans. R. Soc. Lond. A 362, 787 (2004).

[2] F. Huth, et al., Nature Mater. 10, 352 (2011).

[3] F. Huth, et al., Nano Lett. 12, 3973 (2012).

[4] J. Chen, et al., Nature 487, 77 (2012).

Oral Plasmonic Nanopores for Bioanalytical Sensing

1

Magnus P. Jonsson 2 F. Mazzotta 2 F. Höök A. Aksimentiev3 and 1 C. Dekker

1

Bionanoscience Department, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands 2 Division of Biological Physics, Applied Physics, Chalmers University of Technology, Fysikgränd 3, 41296 Gothenburg, Sweden 3 Department of Physics, The University of Illinois at Urbana Champaign, 405 N. Mathews, Urbana IL 61801, USA

432

Solid-state nanopores and plasmonic nanoantennas are two concepts that both have shown valuable for manipulation and investigation of biomolecules and biomolecular interactions, down to the level of single molecules. Nanopore sensing is based on monitoring biomolecular-induced changes in the ionic conductance of an around 10 nm in diameter pore in a thin solid-state membrane.

Plasmonic nanosensors instead utilize that the resonance condition for excitation of plasmons in metal nanostructures is highly sensitive to changes in refractive index close to the nanostructure, as, for example, induced by biomolecular binding reactions. In addition, the excitation of these collective electron oscillations known as plasmons also provides a means to focus and localize light to subdiffraction limited spots with highly intense electromagnetic fields.

Some of the most fascinating applications of such hot spots include surface-enhanced Raman scattering and optical nanotweezing.

In our recent work we combine nanopores and plasmonic nanoantennas into one concept termed plasmonic nanopores (see example in Figure 1). I will discuss how plasmonic nanopore systems can be used to significantly improve nanoplasmonic sensing by using the nanofluidic pores for efficient delivery of target molecules.

[1,2] Vice versa, nanopore sensing could be improved using plasmonic effects, where I will focus on the possibility to control biomolecular translocations using optical forces provided by plasmonic nanoantennas. As an example of a conceptually new application I will present our recently developed optical profiling method based on light-induced plasmonic heating in a single plasmonic nanopore [3].

p.m.jonsson@tudelft.nl

References [1] M.P. Jonsson et al., Analytical Chemistry, 82 (2010) 2087-2094.

[2] F. Mazzotta, F. Höök and M.P. Jonsson.

Nanotechnology 2012, 23 (2012), 415304.

[3] M.P. Jonsson and C. Dekker. In revision.

Figure

Figure 1 Schematic example of a plasmonic nanopore, composed of gold bowtie nanoantenna (yellow) on a thin solid-state membrane (grey) with a nanopore at the gap centre (white).

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Invited Cavity Optomechanics: Exploring the coupling of light and micro- and nanomechanical oscillators

Tobias J. Kippenberg

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using the phenomenon of optomechanically induced transparency(8).

From a broader perspective the described experiments that exploit optomechanical coupling are motivated both by the effort to realize quantum measurement schemes on mechanical systems in an experimental setting as well as to explore the behavior of nanomechanical systems at low temperatures.

References [1] T. J. Kippenberg, K. J. Vahala, Cavity Optomechanics: Backaction at the mesoscale.

Science 321, 1172 (2008, 2008).

[2] T. J. Kippenberg, H. Rokhsari, T. Carmon, A. Scherer, K. J. Vahala, Analysis of RadiationPressure Induced Mechanical Oscillation of an Optical Microcavity. Physical Review Letters 95, 033901 (2005).

[3] V. B. Braginsky, S. P. Vyatchanin, Low quantum noise tranquilizer for Fabry-Perot interferometer. Physics Letters A 293, 228 (Feb 4, 2002).

[4] V. B. Braginsky, Measurement of Weak Forces in Physics Experiments. (University of Chicago Press, Chicago, 1977).

[5] A. Schliesser, P. Del'Haye, N. Nooshi, K. J. Vahala, T. J. Kippenberg, Radiation pressure cooling of a micromechanical oscillator using dynamical backaction. Physical Review Letters 97, 243905 (Dec 15, 2006).

[6] A. Schliesser, R. Riviere, G. Anetsberger, O. Arcizet, T. J. Kippenberg, Resolved-sideband cooling of a micromechanical oscillator. Nature Physics 4, 415 (May, 2008).

[7] E. Verhagen, S. Deleglise, S. Weis, A. Schliesser, T.J. Kippenberg, Nature (2012).

[8] S. Weis et al., Optomechanically Induced Transparency. Science 330, 1520 (Dec, 2010).

433

The mutual coupling of optical and mechanical degrees of freedom via radiation pressure has been a subject of interest in the context of quantum limited displacements measurements for Gravity Wave Detection for many decades, however light forces have remained experimentally unexplored in such systems.

Recent advances in nano- and micro-mechanical oscillators have for the first time allowed the observation of radiation pressure phenomena in an experimental setting and constitute the emerging research field of cavity optomechanics [1].

Using on-chip micro-cavities that combine both optical and mechanical degrees of freedom in one and the same device [2], radiation pressure back-action of photons is shown to lead to effective cooling [3-6] of the mechanical oscillator mode using dynamical backaction, which has been predicted by Braginsky as early as 1969 [4].

This back-action cooling exhibits many close analogies to atomic laser cooling. With this novel technique the quantum mechanical ground state of a micromechanical oscillator has been prepared with high probability using both microwave and optical fields. In our research this is reached using cryogenic precooling to ca. 700 mK in conjunction with laser cooling, allowing cooling of micro-mechanical oscillator to only 1.7 quanta. â&#x20AC;&#x201C; implying the oscillator resides more than 1/3 of its time in the quantum ground state.

Moreover it is possible in this regime to observe quantum coherent coupling in which the mechanical and optical mode hybridize and the coupling rate exceeds the mechanical and optical decoherence rate (7). This accomplishment enables a range of quantum optical experiments, including state transfer from light to mechanics

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EPFL , Switzerland

Oral Magnetization switching by ultrashort acoustic pulses

Oleksandr Kovalenko T. Pezeril and V. V. Temnov

Institut des Molécules et Matériaux du Mans, UMR CNRS 6283 Université du Maine 72085 Le Mans cedex, France.

oleksandr.kovalenko.etu@univ-lemans.fr

434

The knowledge of the fundamental limits of information transfer and data recording rates are crucial for the development of new ultrafast data recording technologies. However, there is a need to develop even faster data recording schemas operating in the terabit per second (Tbit/s) based on new physical principles. Here we study the possibility of ultrafast magnetization switching using THz acoustic pulses which have potential applications in future telecommunication and data recording technologies.

So far the magnetization switching has been demonstrated by applying pulses of magnetic field and spin-polarized current, and, in the most spectacular way, by single circularly polarized femtosecond laser pulses [1]. Trying to take advantage of the recently reported generation of giant ultrashort acoustic pulses in hybrid metalferromagnet structures [2,3] here we present a new concept for the magneto-acoustic switching in Terfenol-D [4].

This rear-earth-based compound is well suited for magneto-acoustic investigations due to the large value of magneto-elastic (magnetostrictive) coupling [5]. The realistic design of a hybrid magneto-acoustic multilayer sample is presented in Fig.1a. An opto-acoustic cobalt transducer excited through the substrate launches through the buffer layer of gold a giant ultrashort acoustic pulse, which is injected in a thin (110) layer of Terfenol-D. If the investigated Terfenol-D film is sufficiently thin and is covered by an acoustically matched dielectric layer, the action of the acoustic pulse can be adequately described by applying an ultrafast but spatially homogeneous time-dependent strain.

The dynamics of magnetization induced by an ultrashort acoustic strain pulse  (t ) can be

described by the Landau-Lifshitz-Gilbert (LLG) equation  dM dt

       M  H eff  [ M  ( M  H eff )], (1) Ms

which

describes

the

precession



of

the

magnetization vector M around the effective



 1 dF   H ext 0 dM

magnetic field H eff  

In the absence of the external magnetic field

 dF H ext 0 it is determined by the gradient  of dM

free on free energy density F with respect to magnetization direction. The second term in Eq. (1) describes the damping of magnetization direction with Gilbert constant   0.1 . The phenomenological expression F  Fk  FMEL  Fd  F for free energy

z

density of Terfenol-D [5] is dominated by the competition of the magnetocrystalline anisotropy 2 2 2 2 2 2 2 2 2 Fk  K1( x  y   x  z   y z )  K 2 ( x  y z )

(2)

and the magnetoelastic energy density 2 2 2 FMEL  b1( x  xx   y yy   z  zz )  b2 ( x y xy   x z xz   z y zy )

(3) The explicit dependence of the magnetoelastic term on the components  ij of the strain tensor and

the

directional

magnetization

cosines



vector M

αi

of

the

 M s ( x ,  y ,  z )

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 ac  

(b2  2b1 ) ' '  y x  (t )dt 2M s



Figures

(4)

This kick angle appears to be proportional to the acoustic pulse area resembling similar phenomena in coherent optics. Numerical simulations show that sufficiently strong acoustic pulses can switch the magnetization vector back and force between two different metastable states 1 and 2 (Fig. 1b). The magneto-elastic phase diagram in Fig. 1c shows that depending on the acoustic pulse duration amplitude, switching is possible between all four metastable magnetization directions. Whereas at short pulse durations below 10 ps the switching strain is inversely proportional to pulse duration, for longer pulses it saturates and reaches the value of 0.3%. Therefore, according to our simulations the conditions for ultrafast magneto-elastic switching in Terfeno-D are experimentally accessible.

Figure 1 (a) Design of a multilayer structure for the acoustic magnetization switching. An opto-acoustic cobalt transducer is excited by an ultrashort optical pulse and generates a giant acoustic pulse with 1% amplitude and 4 ps duration (see Ref. [3] for details). An acoustic pulse propagates through the gold buffer layer and interacts with magnetization in Terfenol. (b) The magnetization vector in a thin (110) Terfenol film possesses four metastable in-plane magnetization directions: 1,2,3 and 4. An ultrashort tensile strain pulse with an amplitude of 0.9% and 3 ps duration ‘kicks’ the magnetization vector out of the sample plane, resulting into its precession and decay into another minimum (magnetization switching between energy minima 1 and 2 occurs). (c) Depending on the duration ac and amplitude  of rectangular acoustic pulses, the magnetization can be switched between its all four metastable states. The initial magnetization state is 2.

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suggests that the application of a time-dependent strain will modify the total free energy density and induce magnetization precession. Whereas for arbitrary acoustic pulses only numerical solutions can be obtained, an ultrashort acoustic pulse  (t ) with a duration significantly shorter than the precession period (about 25 ps in Terfenol-D) results in the ‘out-of-plane kick’ of the magnetization vector by an angle [4]

References

ImagineNano2013

435

[1] C. D. Stanciu et al., Phys. Rev. Lett. 99 (2007) 047601.

[2] V.V. Temnov, Nature Photonics 6 (2012) 728.

[3] V.V. Temnov et al., Nature Communications 4 (2013) 1468.

[4] O. Kovalenko, T. Pezeril and V.V. Temnov, arXiv: 1212.0669 (2012).

[5] . de la Fuente et al., J. Phys. Condens. Matter 16 (2004) 2959.

Oral Nanoscale mapping of the local density of optical states in the near field of a plasmonic antenna 1

Institut Langevin, ESPCI ParisTech & CNRS UMR 7587, 1 rue Jussieu, 75005 Paris, France 2 Laboratoire de Photonique et Nanostructures (CNRS), Route de Nozay, 91460 Marcoussis, France

436

We report on the experimental and theoretical study of the local density of states (LDOS) and intensity fluctuations of the electro-magnetic field at the surface of a plasmonic nanoantenna. The experimental data are acquired by scanning a fluorescent nanoemitter, grafted at the apex of the tip of an atomic force microscope (AFM), in the near-field of the sample. By combining our AFM with a confocal microscope, we can simultaneously measure the topography of the sample, the intensity of the fluorescent emission and the fluorescence decay rate. The last quantity is directly proportional to the LDOS. Some recent results [1] obtained with the experimental setup described above are shown in figure 1. In this case a 100 nm fluorescent bead was scanned on the top of three gold nanodiscs of diameter 150 nm, separated by 50 nm. As one can see, two dimensional maps of the intensity (fig.1b) and the decay rate (fig.1c) of the fluorescent bead show subwavelength details.

A good understanding of these maps is achieved by comparison with exact numerical simulations, which also allows one to analyze the optical response of the fluorescent near-field probe used to perform the experiments. Theory and experiments are in good agreement. Since the near-field images of fluorescence intensity and LDOS provide complementary information, the simultaneous acquisition of the two maps is crucial to achieve a full characterization of the optical properties of the studied sample.

While the study presented here is devoted to the analysis of the optical response of a plasmonic nanoantenna, the developed active AFM can be used for the investigation of the electromagnetic modes on any type of photonic nanostructure. The manipulation of a fluorescent nano-object with nanometer accuracy at the surface of a photonic

Valentina Krachmalnicoff 1 1 D. Cao , A. Cazé 1 1 E. Castanié , R. Pierrat N. Bardou2, S. Collin2 1 R. Carminati and 1 Y. De Wilde

1

valentina.krachmalnicoff@espci.fr

nanostructure opens interesting new perspectives for the realization of quantum optics experiments, such as the investigation of the coupling of quantum emitters with plasmonic (or dielectric) devices, the characterization of electromagnetic modes on photonic nanostructures, or the search for Anderson localized modes in disordered systems [2-4].

References [1] V. Krachmalnicoff, D. Cao, A. Cazé, E. Castanié, R. Pierrat, N. Bardou, S. Collin, R. Carminati, and Y. De Wilde, “Towards a full characterization of a plasmonic nanostructure with a fluorescent near-field probe", submitted (2013).

[2] V. Krachmalnicoff, E. Castanié, Y. De Wilde and R. Carminati, “Fluctuations of the Local Density of States Probe Localized Surface Plasmons on Disordered Metal Films", Phys.

Rev. Lett. 105 (2010) 183901.

[3] E. Castanié, V. Krachmalnicoff, A. Cazé, R. Pierrat, Y. De Wilde, and R. Carminati, “Distance dependence of the local density of states in the near field of a disordered plasmonic film", Opt. Lett. 37 (2012) 3006.

[4] A. Cazé, R. Pierrat and R. Carminati, “Radiative and non-radiative local density of states on disordered plasmonic films", Phot. Nano.

Fund. Appl. 10 (2012) 339.

Figures

Figure 1 Topography (a), fluorescence intensity (b) and fluorescence decay rate (c) maps measured on the top of three gold nanodiscs of diameter 150 nm, separated by 50 nm.

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Invited Purcell factor of photonic and plasmonic nanoantennas

Philippe Lalanne 1 C. Sauvan and 2 J. -P. Hugonin

1

1

~ 

)/Im( ~  )). The formalism allows us to derive a generalized Purcell formula valid for any nanocavity quasi-normal mode with radiative leakage, absorption and material dispersion, including the important case of plasmonic nanoantennas. Our findings are not marginal, as they greatly impact and expand our current understanding of coupling between low Qresonance and dipoles and solve a longstanding problem related to the normalization of quasinormal modes. For instance we show that 1. the contribution of a quasi-normal mode to the total power radiated by a source may be detrimental (it may reduce the emission), even when the frequencies of the source and the mode are matched.

2. a detuning between the quantum emitter and cavity frequencies does not necessarily result in a Lorentzian lineshape response, as it is presently accepted by everyone.

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All our findings are carefully checked and validated by comparison with fully-vectorial numerical results obtained for distinct cavity constructs representative of modern studies in quantum plasmonics. The following figure shows an example of such a test for a gold nanorod (diameter d = 30 nm and length L = 100 nm) embedded in a host medium of refractive index 1.5 (see (a)). Figure (b) shows the normalized decay rates (total and absorption) calculated with the Green-tensor approach (solid curves) and with the proposed model (circles or squares). The dipole is on-axis, parallel to the nanorod axis (red arrow) at a distance d = 10 nm from the metal surface. In (c), we show the same for the resonance frequency as a function of d. The work is presently submitted for publication.

Figures

437

The spontaneous emission of a quantum emitter is a cornerstone of nano-optics, with the objective to control light absorption and emission at the nanometre scale. At the heart of the engineering lies the emitter-cavity coupling. A figure of merit for this coupling is the famous Q/V ratio introduced by Purcell in 1946. During the last decennia, the Purcell factor has been essentially used to fashion purely dielectric microcavities that confine light at the wavelength scale.

In this work, from first-principle calculations based on Maxwell’s equations and the Fermi’s golden rule, we propose a self-consistent theoretical framework of the coupling between a dipole emitter and a cavity quasi-normal mode. The latter is a solution of Maxwell’s equation without source and with a complex frequency ~  . It is an advanced representation of a resonance (2Q = Re (

PPM 2013

Laboratoire Photonique, Numérique et Nanosciences, Institut d’Optique, Univ Bordeaux 1, CNRS, 33405 Talence cedex, France.

2 Laboratoire Charles Fabry, Institut d’Optique, CNRS, Univ Paris-Sud, 2 avenue Augustin Fresnel, 91127 Palaiseau cedex, France.

Oral Kristof Lodewijks 1 I. Zubritskaya 2 R. Dumas J. Åkerman2 1 A. Dmitriev

1

kristof.lodewijks@chalmers.se

Applied Physics, Chalmers University of Technology, Fysikgränd 3, 412 96 Göteborg, Sweden 2 Physics Deparment, Gothenburg University, Fysikgränd 3, 412 96 Göteborg, Sweden

The interaction between magnetic materials and plasmon resonances has been extensively studied in the field of magnetoplasmonics. It was recently shown that ferromagnetic nickel nanoparticles support localized surface plasmon resonances that can be exploited to modify the magneto-optical behavior at will [1]. As such, the magnetization loops that are measured in spectroscopic Magneto-Optical Kerr Effect (MOKE) experiments can show changes both in sign and magnitude depending on the excitation wavelength and its relative position with respect to the localized surface plasmon resonance (LSPR) frequency. The large phase change between both spectral sides of the LSPR and the intrinsic phase shift that the magnetization of the ferromagnetic material induces allows tuning of the magnetization loops by means of the plasmon resonance. Here we show that symmetry breaking adds one more degree of freedom by modifying both the magnetic and optical behavior of the nanoparticles. We studied the magnetization behavior of round and elliptical nickel nanoparticles in longitudinal spectral MOKE, measuring along the different symmetry axes of the system, as illustrated in figure 1.

From the loops in figure 1, it can be seen directly that the short and long axis of the nanoparticles behave as a hard- (red) and easy (blue) axis for the magnetization, which severely alters the magnetization behavior compared to simple round disks (black). When we compare the coercivity between the different particles we see that it is increased (decreased) along the long (short) axis with respect to the values for round nanoparticles.

Moreover, the particles also support 2 pronounced localized plasmon resonances along the 2 symmetry axes of the system, which adds one

438

1

Designer magnetoplasmonics in ferromagnetic nanoparticles through symmetry breaking

more degree of freedom that can be exploited to tailor the magnetoplasmonic response of the system. It was already shown for round disks that a reversal of the sign of the magnetization loops can be achieved by properly designing the size of the nanoparticles and choosing the appropriate measurement wavelength in spectroscopic MOKE measurements.

The tunability of the magnetoplasmonic response originates in the intrinsic phase change induced by the magnetization of the nickel and the interplay with the polarizability of the nanoparticles and the associated phase change between the two spectral sides of the LSPR mode.

Figure 2 shows the overview of the spectral dependence of the magneto-optical response of round and elliptical nickel nanoparticles for P- and S-polarization and different sample orientations.

The axis along which the magnetization was applied is indicated in the different graphs (LA = long axis / SA = short axis). This implies that in Ppolarization the LSPR is excited along the same axis, while for the S-polarization the LSPR is excited along the perpendicular axis.

For the different samples in S-polarization, the behavior looks very similar to what was observed before in round nanoparticles. The magnetization loops change sign in the vicinity of the LSPRwavelength. The behavior of round particles and elliptical particles with the field along the long axis is almost identical, while for the elliptical particles with the field along the long axis the crossing point is red-shifted. This can easily be understood, as in the S-polarization we excite the LSPR perpendicular to the magnetic field direction, so along the short and long axis respectively. Note that with respect to the reference spectrum for a

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Figures

Figure 1 Schematic overview of the measurement configuration in L-MOKE (left) and magnetization loops measured with 800nm wavelength along the different symmetry axis of round (170nm) and elliptical (170/240nm) particles in P-polarization.

PPM 2013

nickel film, at the LSPR the rotation value is pulled down to lower values.

In P-polarization, we observe very different behavior in the elliptical nanoparticles. When the magnetic field is applied along the long axis, the behavior is fairly similar to round disks, although the rotation angle reaches even more negative values at the LSPR along the long axis (800 nm). If the magnetic field is applied along the short axis, the magnetization behaves totally different from all other configurations. In this case, we observe that the LSPR along the short axis (650nm) pulls the rotation angles to much larger values compared to the reference film. In this particular configuration, the induced plasmon dipole is aligned along the magnetic field direction and thus should not experience any pronounced Lorentz force, which implies that this is a very surprising result. By breaking the symmetry of the nanoparticles, not only the magnetic behavior is altered, but also the polarizability along the different symmetry axes of the particles. As such, the phase difference that is picked up in MOKE between the intrinsic magnetization behavior of nickel and the LSPR mode can be tuned to an even larger extent, allowing to tailor the magnetooptical behavior of these nanoparticles at will.

Future applications for such effects include amongst others magnetic memories and (bio-) chemical sensing.

Figure 2 Spectroscopic dependence of the rotation angle in L-MOKE for P- and S-polarization and different sample orientation.

References

ImagineNano2013

439

[1] C. D. Stanciu et al., Phys. Rev. Lett. 99 (2007) 047601.

Oral High Performance Nanosensors Based on Plasmonic Fano-Like Interference

1

Fernando López-Tejeira 2 R. Paniagua-Domínguez 3 R. Rodríguez-Oliveros and J.A. Sánchez-Gil2

1

Universidad de Zaragoza, EINA, María de Luna 3, E-50018 Zaragoza, Spain Instituto de Estructura de la Materia (IEM-CSIC), Serrano 121, E-28006 Madrid, Spain 3 Humboldt-Universität zu Berlin, Lise-Meitner-Haus, Newtonstrasse 15, D-12489 Berlin, Germany 2

440

Unlike those propagating at metal/dielectric interfaces, localized collective oscillations of charges confined to the surface of metal nanoparticles can be directly excited by external illumination without the need of any additional coupling-in technique, provided that particles are much smaller than the incident wavelength.

These oscillations, which can be pictured as a “wave” of electrons moving across the surface of the particle, are referred to as localized surface plasmon resonances (LSPRs) and they are responsible of nanoparticles' bright colors when in colloidal suspension, as a result of their intense absorbing and scattering of light in the visible range.

One of the most appealing properties of LSPRs is that their resonant frequency strongly depends on nanoparticles's size, shape and composition, as well as on the refractive index of the surrounding medium. Given that present technological advances allows one to control particle geometry down to nanometer scale, spectral shift of LSPRs can then be used to detect extremely small changes of the immediate dielectric environment. For instance, such as those produced by the binding of some biological molecules with a higher refractive index than that of their aqueous solvent.

When assessing the actual performance of a refractive index sensing scheme based on the spectral shift of a given plasmon resonance, we have to first consider its refractive index sensitivity, which is defined as the linear regression slope within a given range for the position of the resonance (either a peak or a dip) as a function of refractive index. This magnitude is usually expressed in terms of wavelength or energy shifts per refractive index unit and it provides a preliminary measure of the sensor

flt@unizar.es; flt_jdc@yahoo.es

quality. However, sensitivity alone cannot characterize the sensor performance but in an ideal scenario of infinitely high spectral resolution and no system noise. Sherry et al. [1] therefore proposed the socalled figure of merit (FoM), which is defined as the Plasmon resonance sensitivity divided by its “Full Width at Half Maximum” (FWHM), as the most meaningful indicator for evaluating the performance of LSPRbased sensors. Such dimensionless quantity allows one to directly compare the sensing properties of different systems irrespective of their shape, size and operating wavelength.

According to its very definition, the optimal FoM would then be obtained from those resonances exhibiting both high sensitivity to environment and narrow FWHM, which are precisely the main features of spectral line profiles arising from Fano interference [2]. Such an interaction of discreteand continuum-like states (often labeled as “dark” and “bright” modes) has already been employed for refractive index sensing by means of either propagating or localized Plasmon resonances.

In order to design high performance LSPR-based nanosensors, we have focused our attention to the occurrence of asymmetric line shapes in the scattering spectra of single metallic nanorods acting as half-wave antennas in the optical range.

Contrary to the common assumption that interference does not play a role in the total scattering or extinction of a single metallic surface, we have found [3] that longitudinal plasmon resonances occurring at individual metallic nanoparticles may present Fano-like interaction provided that they overlap in both spatial and frequency domains. Next, we propose [4] two different configurations for which this Fano-like interference can be easily employed in

ImagineNano2013

References [1] L. J. Sherry et al., Nano Letters, 5 (2005) 2034.

[2] B. Luk’yanchuk et al., Nature Materials, 9 (2010) 707.

[3] F. López-Tejeira et al., New Journal of Physics, 14 (2012) 023035.

[4] F. López-Tejeira, R. Paniagua-Domínguez and J. A. Sánchez-Gil, ACS Nano, 6 (2012) 8989.

PPM 2013

refractive index sensing: a colloidal suspension of nanospheroids (nanorice) and a single nanowire with rectangular cross section (nanobelt) on top of a dielectric substrate. We numerically study the performance of the two in terms of their figures of merit, which are calculated under realistic conditions. For the case of nanorice, we explicitly incorporate the effect of size dispersity into the simulations. Our obtained results show that the application of the proposed configurations seems to be not only feasible but also very promising.

Figures

Figure 1 Schematic representation of the emergence of asymmetry in the spectral response of different rod-shaped nanoantennas.

ImagineNano2013

441

Figure 2 Schematic representations of our two proposed configurations for refractive index sensing based on plasmonic Fano-like interference.

Invited Femtosecond Spin-State Photoswitching of Molecular Nanocrystals

Maciej Lorenc E. Collet H. Cailleau R. Bertoni M. Buron and M. Servol

Institute of Physics of Rennes UMR 6251 CNRS - University Rennes, France

maciej.lorenc@univ-rennes1.fr

Controlling molecular states in a solid material with an ultrashort laser pulse poses a new challenge to the ultrafast science, ensuing the now established field of femtochemistry.

Molecular materials can be directed between different macroscopic states by using appropriate electronic, or other, excitations. By contrast to a dilute solute in a passive solvent, all molecules that make up a solid are active and can be switched. Emerging cooperativity and coherence of different degrees of freedom underpin the resulting phase transitions of various sorts. The pertinent time scales for photo-switching processes in materials have been rather difficult to scrutinise. The pioneering investigations dealt mainly with the electron/phonon dynamics immediately following the femtosecond excitation, or the kinetics of recovery to the thermally stable states. In solids, we can expect the dynamics to follow a complex pathway from molecular to material scale through a sequence of processes. Spincrossover (SCO) compounds are excellent photo-active prototypes by virtue of their photomagnetic properties, which can be switched by promoting the constituent molecules to their low-spin or high-spin electronic states.

We scrutinise the switching timescales and the underlying mechanisms by investigating the SCO single crystals [1-3] and the SCO nanocrystal films [4].

[3] M. Lorenc et al., Phys. Rev. B. 85, 054302 (2012).

[4] R. Bertoni et al., Angew. Chem. 51, 7485 (2012).

References

442

[1] M. Lorenc et al., Phys. Rev. Lett. 103, 028301 (2009).

[2] H. Cailleau et al., Acta Cryst. A66, 189 (2010).

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Oral Beri N. Mbenkum 1 T. N. Ackermann 2 A. Vlad L. Shanming3 3 Lin Gu

1

beri.mbenkum@imb-cnm.csic.es

Centro Nacional de Microelectrónica (IMB-CNM), Campus UAB, 08193 Bellaterra (Barcelona), Spain 2 Synchrotron Soleil, L'Orme des Merisiers - Saint-Aubin BP 48, 91192 Gif sur Yvette Cedex, France 3 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

ImagineNano2013

properties of the plasmonic NPs can be studied and utilized simultaneously. The current platform is as an alternate route to shift the spectral response of sub 10 nm NPs beyond their standard regions of expression.

References [1] B. N. Mbenkum, A. Diaz-Ortìz, L. Gu, P. A. Van Aken, G. Schuetz, J. Am. Chem. Soc., 132 (2010), 10671-10673.

Figures

Figure 1 Schematic representation of NPs prepared via diblock copolymer nanolithography: Crosssection of metal-loaded micelle before (left) and during (middle) plasma treatment, respectively.

Representative SEM and high-resolution SEM micrographs (right) illustrate the ordered 2D array of ligand-free Au NPs obtained after plasma treatment

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Nanotechnology has unveiled exotic phenomena in materials while concurrently enhancing or annihilating intrinsic ones. The key to controllably extract and exploit these phenomena is through precise control over the architecture (size, composition and pattern formation) of nanomaterials. Nanoparticles (NPs) are ideal features with properties that enable them to function in a vast range of technological domains.

Assemblies thereof, create configurations which rely either on their individual or collective response to external stimulus. This fundamental understanding has been implemented with plasmonic NPs (e.g. Au, Ag, Cu), to enable the development of e.g. enhanced molecular sensing, energy harvesting and spectroscopic systems.

The spectral properties of plasmonic NPs have so far been found to be fundamentally dependent on the material of the NP as well as its electronic charge or that of the surrounding medium, the spacing between NPs, their shape as well as size.

The presentation will illustrate an enticing means to tune the spectral properties of spherical Au NPs of the same size within a spectral range of ~ 485 – 540 nm, with air as a surrounding medium.

The NPs are ligand-free and adequately spaced out (70 ± 10 nm) to minimize proximity effects. It will also be shown how the spectral properties can be further modified or stabilized with an ultra-thin (~ 1nm thick) dielectric shell around each individual NP. To achieve all this, we employ the concept of diblock copolymer micelle nanolithography to synthesize monodisperse, two-dimensional (2D) arrays of sub 10 nm NPs and core-shell systems. [1] 2D arrays of NPs are used here to exploit the advantage of such a configuration: It provides an interesting regime wherein the individual and or collective

PPM 2013

1

Size - & Shape-Independent Tuning of Plasmon Resonance Frequency of Sub 10 nm Gold Nanoparticles

Invited Cascaded Field Enhancement with Self-Similar Antennas 1 2 3

ETH Zürich, Photonics Laboratory, 8092 Zürich, Switzerland, Institute of Optics, University of Rochester, Rochester, NY 14627, USA; Institute of Physics, University of Münster, 48149 Münster, Germany.

444

Optical antennas consisting of plasmonic materials provide extreme light localization and small mode volumes, thereby boosting the sensitivity and signal-to- noise ratio in applications ranging from single photon sources to photodetection. Optical antennas can also be employed to efficiently control and manipulate light on the nanometer scale and to achieve directional emission.

Different optical antenna designs have been studied over the past years, ranging from colloidal single-particle antennas to more sophisticated multi-element antennas. Antenna gain is the most common figure-of-merit for the performance of antennas and while general design criteria have been developed for the radiowave and microwave frequency regimes, these criteria are not directly scalable to optical antennas. The reason is that because of the finite electron density, optical radiation penetrates into metals and gives rise to an effective wavelength shortening, which leads to an increase of kinetic inductance and a reduction of radiation efficiency. Thus, the directed design and optimization of optical antennas remains an open challenge.

In this presentation we will demonstrate that high antenna gains can be achieved by self-similar antennas [1,2]. These self-similar antennas consist of arrays of gold nanoparticles of different size.

The local field enhancement is probed by single molecule fluorescence using fluorophores with high intrinsic quantum efficiency (Qo > 80%). Using a self-similar trimer antenna consisting of a 80nm, 40nm and 20nm gold nanoparticle, we demonstrate a fluorescence enhancement of 40 and a spatial confinement of 15 nm. Compared to a single gold nanoparticle, the self-similar trimer antenna improves the enhancement-confinement ratio by more than an or- der of magnitude. Self-

1,2

Lukas Novotny 2,3 C. Höppener 1,2 Z. J. Lapin and P. Bharadwaj1,2

lnovotny@ethz.ch

similar antennas hold promise for high-resolution imaging and spectroscopy, ultrasensitive detection and efficient single photon sources.

References [1] K. Li, M. I. Stockman, and D. J. Bergman, Phys.

Rev. Lett. 91, 227402 (2003).

[2] C. Höppener, Z. J. Lapin, P. Bharadwaj, and L. Novotny, Phys. Rev. Lett. 109, 017402 (2012).

Figures

Figure 1 Excitation of single molecule fluorescence with a trimer antenna consisting of an 80 nm, 40 nm, and 20 nm gold nanoparticle. (a) Fluorescence image of the single molecule sample.

Inset: Line-cut through the single fluorescence spot marked by the arrow. (b) Fluorescence from a single z-oriented molecule recorded as a function of distance from a trimer antenna. The steep rise of fluorescence counts for separations smaller than 15 nm is due to strong field localization along the z-axis at the apex of the trimer antenna.

ImagineNano2013

Oral Localized Surface Plasmons Resonances on GaSb-based materials for Infrared applications

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Etching (RIE) with Cl2, N2 and Ar [7]. This method provides vertical sidewalls and the conservation of the mask shape and precludes parasitic resonances in the reflectivity spectrum. We thus obtain a grating period of 540nm with a constant ribbon width of 240nm. Some samples were overgrown with a 600 nm-thick GaSb layer in a second epitaxy step. This method planarizes the surface on the grating.

Reflectance experiments have been performed using a Fourier Transform Infrared (FTIR). Figure 1 present spectra for s and p polarizations (black and red lines respectively) for a 100nm-thck InAsSb array with a period p=540nm and a ribbon width w=240 nm. The inset shows a profile view of the array obtained by Scanning Electron Microscopy (SEM). As expected, the s-polarized incident light cannot excite surface plasmons, whereas in p-polarization we can see a resonance in the reflectance spectra around 12 µm. The smaller one at 10µm is due to the trapezoidal shape of the array. Both are signatures of the LSP modes at the interface between InAsSb and GaSb material. In fact, these resonances are affected to LSP because of the very small period of the array compared to the wavelength of incident light [8].

This is confirmed by angular resolved reflectance.

The wavelengths of the LSP resonances are sensitive to the size and the shape of the grating.

They follow a similar behavior than in the case of metallic particles [9].

We also performed reflectivity measurements on an InAsSb array encapsulated by a GaSb layer (black line) and compare it with the spectrum obtained for uncovered InAsSb array. This is reported on figure 2. The main observation is the red-shift of all the resonances observed in InAsSb/air array. It moves from 12 µm for an InAsSb/air system to 14µm for an InAsSb/GaSb

PPM 2013

We propose to realize and to study an allsemiconductor plasmonic structure based on GaSb materials. Composed of a highly-doped InAsSb sub-wavelength arrays lattice-matched to a GaSb substrate, it supports Localized Surface Plasmons (LSP). The resonance frequencies can be modulated by adjusting the dielectric function of the surrounding material and by adapting the geometry of the array.

The use of Surface Plasmons Polaritons (SPP), electromagnetic excitations at the metaldielectric interface, offers the ability to control the light mater coupling which is an exciting topic of research. Traditionally, noble metals like gold are employed for plasmonic devices, to obtain wave-guiding [1], biosensing [2] or metamaterials [3]. However, many studies show the benefit of using semiconductors materials instead of metals, especially in the infrared range [4, 5].

Here, we propose an experimentally study demonstrating that for a highly Si-doped InAsSb layer on GaSb substrate, it is possible to design plasmonic structures which exhibits Localized Surface Plasmons Resonances in the midinfrared.

The InAsSb layer is 100 nm thick and latticematched to the GaSb substrate by adjusting the amount of Sb. Moreover, electrons in InAsSb have a small effective mass and the material can then be easily doped at high value (up to few 1020 cm-3) to obtain plasmonic resonances in the midinfrared [6]. The Si concentration varies from 1019 cm-3 to 1020 cm-3 which is confirmed by Secondary Ionization Mass Spectroscopy (SIMS) and Hall effects measurements.

To create the InAsSb array on large areas, a holography insolation is realized using an AZMIR 701 diluted positive photoresist. Then, InAsSb material is etched by chlorine-based Reactive Ion

ntsame@ies.univ-montp2.fr

445

Institut d’Electronique du Sud, CNRS-INSIS-UMR 5214, Université Montpellier 2, 34095 MONTPELLIER cedex 05, France

Vilianne Ntsame Guilengui L. Cerutti J.-B. Rodriguez E. Tournié and T. Taliercio

system, with an enhancement and a shape modification of the resonance. Since Surface Plasmons are sensitive to changes in their surroundings. Adding GaSb material creates this shift. Interferences at shorter wavelengths are due to the superposition of layers.

This present work is the demonstration of the possibility to elaborate an all-semiconductor plasmonic device operating in the infrared.

Figures

References

446

[1] Leilei Yin, Vitali K. Vlasko-Vlasov ,John Pearson ,Jon M. Hiller ,Jiong Hua ,Ulrich Welp , Dennis E. Brown ,Clyde W. Kimball, Nano Lett. 5 (7), (2005) 1399–1402.

[2] Kabashin, A. V., Evans, P., Pastkovsky, S., Hendren, W., Wurtz, G. A., Atkinson, R., Pollard, R., Podolskiy, V. A. and Zayats, A. V., Nature Mate 8 , (2009) 867–871.

[3] Smith, D. R., Pendry, J. B. and Wiltshire, M. C. K., Metamaterials and Negative Refractive Index, Science, 305, 788 (2004).

[4] Cleary, J. W., Medhia, G., Peale, R. E., Buchwald, W. R., Edwards, O., and Oladeji, I., Proc. of SPIE Vol. 7673, 767306 (2010).

[5] Joseph M. Luther, Prashant K. Jain,Trevor Ewers and A. Paul Alivisatos, Nature Materials 10,(2011)361–366.

[6] Tokumitsu, E.,Jpn. J. Appl. Phys. 29, L698 (1990).

[7] Lee, J. W., Hong, J., Abernathy, C. R., Lambers, E. S., Pearton, S. J., Hobson, W. S., Ren, F., Journal of Vacuum Sci. and Technol.

14, 2567-2573 (1996).

[8] Ntsame Guilengui V., Cerutti, L., Rodriguez, J.-B., Tournie, E., Taliercio, T., Appl. Phys.

Lett. 101, 161113 (2012).

[9] Gomez C., J. Phys. Chem. C, 111, 10,( 2007) 3806–3819.

Figure 1 Reflectivity spectra in s (black line) and p (red line) polarizations for a 100nm-thick InAsSb/air grating on Gasb substrate. The inset shows a SEM view of the grating with the following dimensions: p=540 nm and w=240 nm. LPSR are only visible in s polarization.

Figure 2 Reflectivity spectra in s polarization for a InAsSb/air grating (red line) and InAsSb/GaSb grating (black line). The SEM image in the inset represents a InAsSb grating with p=540 nm and w= 240 nm. The layer of GaSb is 600 nm-thick. A red shift of LSPR is observed for the encapsulated structure.

ImagineNano2013

Oral Transport and Sensing in Plexcitonic Nanocavities

Olalla Pérez-González1,2 1,2 N. Zabala and Javier Aizpurua2

1

ImagineNano2013

BDP+ and BDP- in Fig. 1a)). Furthermore, the Charge Transfer Plasmon (CTP) resonance, involving a net current through the junction, emerges when the conductance G through the linker is above a threshold value GCTP [7,8].

The results have been generalized to consider molecular linkers presenting different resonances in the range of Eex = 0.62-3 eV (λ0 = 2000-413 nm).

In particular, in Figure 1b) (above), where the radius of the molecular linker is fixed to a = 3nm and its corresponding excitation energy is Eex = 1.24 eV (λ = 1000 nm), the splitting of the BDP plasmon resonance into BDP+ and BDP- plexcitons is also observed.

Since the use of metallic NPs as sensors is one of the most promising applications of plasmonics, we have explored the possibilities of the plexciton nanocavity for sensing. Figure 1b) shows the evolution of the optical extinction cross-section of a NP dimer bridged by a molecular linker with radius a = 3nm and excitation energy Eex = 1.24 eV (λex = 1000 nm), as the dielectric response of the embedding medium εd is varied. The BDP+ plexciton mode red-shifts and gains intensity as εd is increased, indicating that it is adequate for standard shiftbased sensing. In contrast, the BDP- plexciton is hardly red-shifted while its intensity is dramatically increased. This indicates that the sensitivity of the BDP- plexciton might be exploited in an alternative way to shift-based sensing, involving the variation of the intensity of the spectral peaks.

We believe that the study of this kind of spectral changes in plasmonic nanocavities might lead to a deeper knowledge on plasmonic structures for active devices.

PPM 2013

In the last years fundamental advances have been achieved in the fields of molecular electronics [1] and plasmonics [2]. In particular, the optical properties of plasmonic dimers with different shapes have been deeply studied and explained using exact numerical calculations and hybridization models [3]. Recent experiments, such as the simultaneous measurements of electronic conduction and Raman spectroscopy in molecular junctions [4], have suggested the possibility of sensing individual molecules, connecting both fields.

Boosted by the recent interest in molecular switches [5], we have studied the optical response of a gold nanoparticle (NP) dimer bridged by a molecular junction with an excitonic transition. The dielectric response of the linker is characterised by a Drude-Lorentz model, which takes into account the excitation energy Eex of the bridging molecule. We connect the NPs with a cylindrical region of radius a mimicking the molecules, and we observe the evolution of the optical properties of the whole system as the bridge becomes wider. Electromagnetic fields and optical extinction cross-sections are obtained from full electrodynamical calculations with a Boundary Element Method (BEM) [6].

Figure 1a) shows the evolution of the optical extinction cross-section of a gold NP dimer, with radius R = 50 nm and gap d = 1 nm between them, as the radius of the molecular junction is increased up to a = 25 nm. The excitation energy of the molecules is Eex = 1.51 eV (λ = 820 nm). The Bonding Dimer Plasmon (BDP) and the Bonding Quadrupolar Plasmon (BQP) resonances, arising respectively from the hybridization of the dipolar and quadrupolar modes of the individual NPs, couple to excitons giving rise to new coupled plasmon-exciton modes called plexcitons (see

beri.mbenkum@imb-cnm.csic.es

447

Department of Electricity and Electronics, University of the Basque Country (UPV-EHU), Leioa, Spain 2 Center of Materials Physics and Donostia International Physics Center (DIPC), Donostia, Spain

References [1] T. Dadosh, Y. Gordin, R. Krahne, I. Khivrich, D. Mahalu, V. Frydman, J. Sperling, A. Yacoby and I. Bar-Joseph, Nature 436, (2005) 677.

[2] J. Aizpurua, G.W. Bryant, L.J. Ritcher and F.J. García de Abajo, Phys. Rev. B 71, (2005) 235420.

[3] J.B. Lassiter, J. Aizpurua, L.I. Hernández, D.W. Brandl, I. Romero, S. Lal, J.H. Hafner, P. Nordlander and N.J. Halas, Nano Lett. 8, (2008) 1212.

[4] D.R. Ward, N.J. Halas, J.W. Ciszek, J.M. Tour, Y. Wu, P. Nordlander and D. Natelson, Nano Lett. 8, (2008) 919.

[5] Y.B. Zheng, Y.W. Yang, L. Jensen, L. Fang, B.K. Juluri, A.H. Flood, P.S. Weiss, J.F. Stoddart and T.J. Huang, Nano Lett. 9, (2009) 819.

[6] F.J. García de Abajo and A. Howie, Phys. Rev. Lett. 80, (1998) 5180.

[7] O. Pérez-González, N. Zabala, A.G. Borisov, N.J. Halas, P. Nordlander and J. Aizpurua, Nano Lett. 10, (2010) 3090.

[8] O. Pérez-González, N. Zabala and J. Aizpurua, New J. Phys. 13, 083013 (2011).

Figures

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Figure 1 a) Optical extinction cross-section of a gold NP dimer bridged by molecular linkers with an excitonic transition of energy Eex =1.51 eV (λex = 821 nm), as a function of the radius a and conductance G of the linker. b) Optical extinction cross-section of a dimer bridged by a molecular linker with radius a= 3nm and excitation energy Eex = 1.24 eV (λex = 1000 nm) as the dielectric response of the embedding medium εd is varied.

ImagineNano2013

Oral

1

Centro de Física de Materiales CFM (CSIC-UPV/EHU) and Donostia International Physics Center (DIPC), P. Manuel de Lardizabal 5, 20018 San Sebastián, Spain 2 Experimental Solid State Group, Department of Physics, Imperial College London 3 Departamento de Física Aplicada, Universidad de Cantabria, Avenida de los Castros s/n, 39005 Santander, Spain 4 Departamento de Física de la Materia Condensada and Instituto Nicolas Cabrera, Universidad Autonoma de Madrid, 28049 Madrid, Spain

ImagineNano2013

1

*aizpurua@ehu.es

efficiency of the emission for an electric and magnetic dipolar emitter, respectively, oriented both along and perpendicular to the dimer axis, placed in the geometrical center of the dimer.

Reduced quenching and high quantum efficiency of emission are some of the clear advantages of dielectric nanoantennas over metallic ones.

References [1] A. Garcia-Etxarri et al., Opt. Express. 19, 4815 (2011).

[2] J. M. Geffrin et al., Nat. Comm. 3, 1171 (2012).

[3] Mikolaj K. Schmidt et al., Opt. Express. 20, 13636 (2012).

Figures

Figure 1: Extinction spectra of two interacting electric and magnetic dipoles calculated using the dipole-dipole model compared with the full electrodynamical calculation (FDTD) for a Si dimer of radius 150 nm and gap 10 nm. This basic model provides a full understanding of the extinction spectrum.

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Submicron spheres made of low-loss dielectric materials with moderately high refractive index, such as Silicon, show spectrally distinct and well defined electric and magnetic dipolar resonances at optical-near infrared frequencies [1]. This magneto-dielectric response leads to antenna effects that generate enhanced scattering and enhanced local fields. In addition, submicron silicon particles qualify as good dielectric nanoantennas due to both absence of absorption and directional scattering properties [2]. Here, we study the potential of submicron silicon dimers as building blocks for low-loss field-enhanced spectroscopy and sensing of magnetic activity.

We perform a full electrodynamical study of submicron silicon dimers and address their antenna properties in the optical and nearinfrared range of the spectrum.

An analytical dipole-dipole model is developed to understand the basic interactions responsible for the antenna properties. The electric-electric, magnetic-magnetic and the electric-magnetic dipole interactions are the basic interactions responsible for the far-field optical response of a Si dimer of 150 nm radius and 10 nm gap, as shown in Fig. 1. This configuration also shows a significant near-field enhancement in the dimer gap, which makes it a good candidate as a dielectric antenna for field-enhanced spectroscopy.

Furthermore, dielectric antennas have been proven to control the emission from electric and magnetic dipolar emitters coupled to the antenna modes [3]. We thus study the enhancement of the fluorescence of electric and magnetic dipolar emitters when coupled to the antenna modes of the silicon dimer. Fig. 2 and Fig. 3 show the radiative rate enhancement (ΓR/Γ0) and quantum

Mohamed Ameen Poyli 1,2 P. Albella 1 M. K. Schmidt S. A. Maier2 3 F. Moreno 4 J. J. Saenz and 1,* J. Aizpurua

PPM 2013

Dielectric Gap-nanoantennas for Lowloss Field Enhanced Spectroscopy

Figure 2: Radiative decay rate enhancement and quantum efficiency of emission of an electric dipole emitter placed in the dimer gap for different orientations of the emitter calculated for different dimer gaps.

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Figure 3: Radiative decay rate enhancement and quantum efficiency of emission of a magnetic dipole emitter placed in the dimer gap for different orientations of the emitter calculated for different dimer gaps.

ImagineNano2013

Invited Controlling the interaction of light with the very small

Romain Quidant

romain.quidant@icfo.es

ImagineNano2013

we are able to retrieve the actual local field enhancement within the gap [3].

Beyond permanent immobilization, the second approach we discuss here consists in raster scanning the nano-object of interest above the plasmonic structure. In particular we report on the use of optical tweezers to trap and manipulate an individual diamond nanocrystal hosting a single Nitrogen Vacancy (NV). Remarkably, we find the NV axis is nearly fixed inside the trap and can be controlled in-situ, by adjusting the polarization of the trapping light. By combining this unique spatial and angular control with coherent manipulation of the NV spin and fluorescent lifetime measurements near an integrated photonic and plasmonic systems, we prove optically trapped NV center as a novel route for both 3D vectorial magnetometry and sensing of the local density of optical states [4].

References [1] A. G. Curto et al, Science 329, (2010) 930.

[2] C. Galloway et al, submitted (2013).

[3] E. Bermúdez Ureña et al, Adv. Mater. 24, (2012) 314.

[4] M. Geiselmann, M. L. Juan, J. Renger, J. M. Say, L. J. Brown, F. J. García de Abajo, F. Koppens, R. Quidant, Nature Nanotechnol. 8, (2013) 175.

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Extensive research in plasmonics over the last decade has demonstrated the ability of noble metal nanostructures to control optical fields on the nanometer scale. Such concentration of light, well beyond the limit of diffraction, potentially opens new opportunities for enhanced interaction with tiny amounts of matter down to the single molecule/atom level. In practice though, fully exploiting the capability of plasmonics requires nanoscale positioning of the molecule/atoms within the hot spot, where the light is concentrated.

In this talk, we first present different experimental strategies to accurately control the interaction of topdown metallic nanostructures with few to single molecules or artificial atoms. We then discuss some applications to different areas including nanochemistry and biosensing.

The first approach we discuss is based on immobilizing a nano-object of interest (either a molecule, a nanoparticle or a qdot) at a predefined location of the plasmonic nanostructure, and more especially in the hot spot where the plasmonic field is concentrated. A first technique consists in combining e-beam lithography with surface chemistry to define a functionalized nanowell in which the nano-object can bind [1]. Along the same line, we report on another technique in which the immobilization within the hot spot is triggered by a photochemical process that creates a chemical bond that acts as a scaffold for the subsequent immobilization of a nano-object of interest [2]. As an illustration of the potential of these techniques, we demonstrate reproducible immobilization of single qdots in the gap of gold dimers. The delivered qdot is used as a nanoprobe of the plasmonic hot spot. By monitoring the change in the X/BX ratio via lifetime measurement,

PPM 2013

ICFO-The Institute of Photonic Sciences, Castelldefels (Barcelona), Spain and ICREA – Institució Catalana de Recerca I Estudis Avançats, Barcelona, Spain

Oral Theoretical and experimental analysis of the directionality of the electromagnetic scattering by magnetodielectric small spherical particles

Juan Jose Sáenz

2,3

J.M. Geffrin1 R. Gómez- Medina2, P. Albella3 L.S. Froufe-Pérez4, C. Eyraud1 A. Litman1, R. Vaillon5 F. González6 M. Nieto-Vesperinas7 and F. Moreno6

1

Institut Fresnel, CNRS, Aix-Marseille Université, Ecole Centrale Marseille, , 13013 Marseille, France Dep. de Física de la Materia Condensada and Instituto “Nicolás Cabrera”, UAM, 28049 Madrid, Spain.

Material Physics Center CSIC-UPV/EHU and DIPC, Paseo Manuel de Lardizabal 5, Donostia, 20018, Spain.

4 Instituto de Estructura de la Materia, CSIC, Serrano 121, 28006 Madrid, Spain.

5 Université de Lyon, CNRS, INSA-Lyon, UCBL, CETHIL, UMR5008, F-69621, Villeurbanne, France 6 Grupo de Óptica, Dep. Física Aplicada, Univ. Cantabria, Avda. de Los Castros s/n, 39005 Santander, Spain.

7 Instituto de Ciencia de Materiales de Madrid, CSIC, Campus de Cantoblanco, 28049 Madrid, Spain 2 3

Magnetodielectric small spheres present unusual electromagnetic scattering features, theoretically predicted a few decades ago by Kerker et al. [1].

However, achieving such behavior has remained elusive, due to the non-magnetic character of natural optical materials or the difficulty in obtaining low-loss highly permeable magnetic materials in the gigahertz regime. Here we present unambiguous experimental evidence that a single low-loss dielectric subwavelength sphere of moderate refractive index (n≈4 like some semiconductors (Si, Ge) at near-infrared) and radius a<λ radiates fields identical to those from equal amplitude crossed electric and magnetic dipoles, and indistinguishable from those of ideal magnetodielectric spheres. The measured farfield scattering radiation patterns (see Fig. 1(a)) and degree of linear polarization (3–9 GHz/33– 100mm range) show that, by appropriately tuning the a/λ ratio, zero-backward (‘Huygens’ source) or almost zero-forward (‘Huygens’ reflector) radiated power can be obtained [2]. Also, the near-field scattering distributions and their correlation with those measured in far-field, are numerically calculated and analyzed (see Fig. 1(b)). These Kerker scattering conditions [1] only depend on a/λ. Our results open new technological challenges from nano and microphotonics to science and engineering of antennas, metamaterials and electromagnetic devices.

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Acknowledgements: We acknowledge helpful discussions with I. Suárez-Lacalle and José Mª Saiz. R.V., and J.M.G. acknowledge the technical expertise brought and the work done by B. Lacroix (CETHIL) over recent years to improve some parts of the measurement device. This work was supported by the Spanish Ministerio de

juanjo.saenz@uam.es

Ciencia e Innovación through grants: Consolider NanoLight (CSD2007-00046), FIS2009-13430-C01 and C02, FIS2010-21984, as well as by the Comunidad de Madrid (Microseres-CM, S2009/TIC-1476). L.S.F.-P. acknowledges the financial support from the JAE- Program of the Spanish Council for Scientific Research (CSIC) cofunded by the European Social Foundation (ESF).

References [1] Kerker, M., Wang, D.S. & Giles, L. Electromagnetic scattering by magnetic spheres. J. Opt. Soc. Am. 73, (1983) 765–767.

[2] Geffrin, J.M. et al. Magnetic and electric coherence in forward - and back-scattered electromagnetic waves by a single dielectric subwavelength sphere. Nat. Commun.

3:1171 doi: 10.1038/ncomms2167 (2012).

Figures

Figure 1 (a) Far-Field (experiment (blue line), theory (black line)) and (b) Near field intensity distributions of a subwavelength dielectric sphere (refractive index˜4+0i), illuminated by a linearly polarized monochromatic wave (white arrow), for the two Kerker frequencies: Zero-backward: 3.6GHz (left in (a), top in (b)) and near zero-forward: 4.3GHz (right in (a), bottom in (b)).

ImagineNano2013

Invited Improving the resolution of optical far-field microscopes using structured illumination

Anne Sentenac

anne.sentenac@fresnel.fr

In this talk, we will show how using structured illumination permits to improve significantly the resolution of far-field microscope, either for fluorescent samples or for unstained samples.

This technique consists in recording many images of the same sample under various illuminations.

A reconstruction algorithm [1] is then used to extract the super-resolved map of the sample from the stack of images. The ultimate resolution of the microscope is strongly dependent on the spatial frequency content of the illuminations.

Structured illumination microscopy using unknown speckle patterns [2].

PPM 2013

Institut Fresnel, Faculté St Jérôme case 161, 13 397 Marseille, France

References

ImagineNano2013

453

[1] E. Mudry et al, Nature Photonics, 6, 312–315 (2012).

[2] Volume: J. Girard et al, Phys. Rev. lett., 109, (2012).

Oral The nanostructured acoustic Fresnel lens for focusing THz phonons in gold

Institut des MolĂŠcules et MatĂŠriaux du Mans, UMR CNRS 6283, UniversitĂŠ du Maine, 72085 Le Mans cedex, France

Tremendous progress in nano-photonics using hybrid metal-ferromagnet nanostructures [1,2] was recenty extended to acoustics with THz frequency waves [3]. The ability to focus THz frequency phonons with acoustic wavelength of a few nanometers would extend the horizons of nano-photonics with plenty of exciting applications in life sciences and data recording technologies.

Photoacoustic imaging and spectroscopy represent a bunch of widely used techniques exploiting generation and detection of high frequency ultrasound for imaging and nondestructive characterization of biological objects [4]. In some cases, in order to generate acoustic images with ~100 MHz frequency acoustics waves the researchers are using an acoustic Fresnel zone plate [5]. By analogy with optics it consists of a set of rings with different radius to provide constructive interference in a focal point.

Here we consider the possibility to focus sound waves in the terahertz (THz) frequency range (acoustic wavelength of the order of a few tens of nanometers) by a miniature Fresnel lens presented on Fig. 1a. The proposed Fresnel lens consists of a thin cobalt layer (40 nm) sandwiched between a dielectric substrate and a crystalline (111) layer of gold (500 nm, equal to the focal length). A sequence of five rings (with the outer radius of 400 nm) can be etched in cobalt by electron lithography before sputtering the gold layer on top. The cobalt thickness of 40 nm is chosen such that acoustic wave at 0.1 THz frequency propagating through gold and cobalt

Viktor Shalagatskyi V. V. Temnov

viktor.shalagatskyi.etu@univ-lemans.fr

reflections at these interfaces can be neglected and the acoustic Fresnel lens generates spatial phase modulation.

The geometrical path difference of acoustic waves coming to the focal spot from the two adjacent zones in a Fresnel lens is also equal to , leading to the constructive interference of sound waves in the focal point.

In the isotropic approximation such Fresnel zone plate would generate a spatially isotropic acoustic strain distribution in a focal spot with a diameter of 60 nm (FWHM), as shown in Fig. 1b. However, due to the high acoustic anisotropy in gold crystal the intensity distribution in the focal plane is strongly distorted resembling the lattice symmetry (i.e. the 3-rd order symmetry (111) axes in cubic gold) along the propagation direction, see Fig. 1c.

This structure makes it possible to focus longitudinal phonons with frequency of 0.1THz (acoustic wavelength in gold (111) direction equals to 34 nm) down to the spot size below 60 nm (FWHM). Therefore our Fresnel lens can be used in sub-100 nm ultra-high resolution microscopy. A more complicated version of the Fresnel lens with asymmetric zones can be developed to compensate for focal distortions and create a perfect focus like in Fig. 1b.

By analogy with optical tweezers that use fieldgradient force of a highly focused laser beam to trap and move microscopic dielectric objects, our acoustic Fresnel lens can be also used for acoustic trapping of tiny living objects (viruses, cells of cancer etc.) with particle size larger than acoustic wavelength (in the so-called Mie regime).

454

accumulate a phase difference of . A good acoustic impedance matching between gold, cobalt and sapphire [3] suggests that acoustic

ImagineNano2013

References

Figures

PPM 2013

[1] V.V. Temnov, Nature Photonics 6 (2012) 728.

[2] G. Armelles et al., Advanced Optical Materials 1 (2013) 10.

[3] V.V. Temnov et al., Nature Communications 4 (2013) 1468.

[4] L.V. Wang, Photoacoustic imaging and spectroscopy, CRC Press (2009).

[5] B. Hadimioglu et al., Ultrasonics Symposium (1993) 579.

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Figure 1 (a) Model of the nanostructured acoustic Fresnel lens showing the focusing of a monochromatic sound wave at frequency of 0.1 THz into the small acoustic focal spot of 60 nm. (b) An ideal distribution of strain in focal plane for an isotropic case. (c) Strain distribution taking into account the acoustic anisotropy in gold. For this case the maximum intensity in the central spot is observed 200 nm beyond the expected focal distance, i.e. in a 700 nm thick gold layer.

Oral Optical forces on cylinders near subwavelength slits illuminated by either a Gaussian beam or a photonic nanojet: effects of extraordinary transmission and excitation of Mie resonances

Francisco J. Valdivia-Valero M. Nieto-Vesperinas

fvaldivia@icmm.csic.es mnieto@icmm.csic.es

Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC) Sor Juana InĂŠs de la Cruz, 3, Cantoblanco, 28049 Madrid, Spain

456

Studies on optical forces on micro- and nanoobjects, both in their applications of trapping [1] and optical binding [2], show the sensitivity of these techniques of thermal action on the kinetics of these systems. This involves to increase both the numerical aperture NA and the power of the illuminating beam [3] to control the experiments; the former procedure has obvious limitations for thermal manipulation of biological specimens. The effectiveness of optical trapping increases [3, 4] by illuminating particles through subwavelength apertures in extraordinary transmission [5], namely one excitation of the aperture morphology-dependent resonances (MDR). This allows lower illumination power and its performance is greatly improved [4] when also the Mie resonances of the particles are excited, i. e. their whispering gallery modes (WGM) [6] or localized surface plasmons (LSP) [7]. This enhances the aperture transmittance and localization of light [8-10]. Nevertheless, illuminating with photonic nanojets (PNJ) [11] constitutes an alternative mean to enhance that transmission and localization of light through apertures [12]. PNJs have subwavelength spatial resolution [13] and hence are of great interest of microscopy and detection at the nanoscale [14].

Since, however, they are non-resonant focusing effects, their appearance is not so narrowly constrained by the constitutive parameters and morphology of the particles as Mie resonances are.

We calculate, by means of Maxwell Stress Tensor and a finite element method, optical forces exerted on both dielectric and metallic particles, i. e. infinite cylinders, in or out their Mie resonances, near a subwavelength slit in extraordinary transmission regime. Thus, this

latter is illuminated in p-polarization, by either a Gaussian beam or a photonic nanojet. We show the different effects of these particle resonances on the optical forces; namely, while whispering gallery modes under those illumination conditions weaken the force strength, this latter is enhanced by localized plasmon excitation. We show that, the presence of the slit already enhancing by two orders of magnitude the transversal forces of optical tweezers from a beam alone, optical forces additionally incremented by a factor between 3 and 10, at the exit of the aperture, can be reached by illuminating the slit by means of a photonic nanojet. In the first case, we demonstrate a force enhancement, also of binding nature, at plasmon resonance wavelengths on metallic nanocylinders [15]. The role of both scattering and gradient forces are addressed, for the particles at either the exit or entrance of the slit, regarding the bonding or antibonding nature of the overall force on them. In the second case, the presence of the slit can also change the pulling nature of the force that the direct illumination by the nanojet exerts on the small metallic particle in resonance, becoming repulsive at certain lateral positions of this latter [16].

References [1] A. Ashkin, J. M. Dziedzic, J. E. Bjorkholm, S. Chu, Optics Letters, 11 (1986) 288.

[2] P. C. Chaumet, M. Nieto-Vesperinas, Physical Review B, 64 (2001) 035422.

[3] M. L. Juan, R. Gordon, Y. Pang, F. Eftekhari, R. Quidant, Nature Physics, 5 (2009) 915.

ImagineNano2013

ImagineNano2013

PPM 2013

Figures

Figure 1 (a)Example of calculation of optical forces (arrows) and intensity, norm of the time-averaged Poynting vector |<S>| (colors) on a Si cylinder at the exit of a slit practiced through an Al slab. A Gaussian beam impinges on the slit. (b) A slit similar to that of (a) illuminated by a photonic nanojet focused through a silica microcylinder. This mechanism exerts enhanced optical forces on an Ag nanocylinder at the exit of the slit. Map of |<S>| (colors) and <S> (arrows).

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[4] F. J. Valdivia-Valero, M. Nieto-Vesperinas, Optics Express, 20 (2012) 13369.

[5] T. W. Ebbesen, H. J. Lezec, H. F. Ghaemi, T. Thio, P. A. Wolff, Nature, 391 (1998) 667.

[6] J. R. Arias-Gonzรกlez, M. Nieto-Vesperinas, Optics Letters, 25 (2000) 782.

[7] S. A. Maier, H. A. Atwater, Journal of Applied Physics, 98 (2005) 011101.

[8] F. J. Valdivia-Valero, M. Nieto-Vesperinas, Optics Communications, 284 (2011) 1726.

[9] F. J. Valdivia-Valero, M. Nieto-Vesperinas, Optics Express, 18 (2010) 6740.

[10] F. J. Valdivia-Valero, M. Nieto-Vesperinas, Journal of Nanophotonics, 5 (2011) 053520.

[11] Z. Chen, A. Taflove, V. Backman, Optics Express, 12 (2004) 1214.

[12] F. J. Valdivia-Valero, M. Nieto-Vesperinas, Optics Express, 19 (2011) 11545.

[13] X. Li, Z. Chen, A. Taflove, V. Backman, Optics Express, 13 (2005) 526.

[14] A. Heifetz, K. Huang, A. V. Sahakian, X. Li, A. Taflove, V. Backman, Applied Physics Letters, 89 (2006) 221118.

[15] F. J. Valdivia-Valero, M. Nieto-Vesperinas, Optics Express, 20 (2012) 13368 [16] F. J. Valdivia-Valero, M. Nieto-Vesperinas, Optics Communications, 13 (2013) http://dx.doi.org/10.1016/j.optcom.2012.12.

025.

Invited Non-dipolar & magnetic interactions with optical antennas

1,3

Niek van Hulst 1 1 A. Curto , I. Hancu 1 1 M. Kuttge , M. Castro-L贸pez and T. Taminiau2

Niek.vanHulst@ICFO.eu 1

ICFO - The Institute of Photonic Sciences, Castelldefels, Barcelona 2 Kavli Institute of Nanoscience Delft, the Netherlands 3 ICREA - Barcelona

Plasmonic antennas are ideal to manage the interaction with single photon emitters, such as quantum dots or fluorescent molecules [1].

Tailoring the electromagnetic mode one can control electronic transitions rates and angular emission patterns, which is key for bright directed single photon sources [2]. Here we present three different examples of hybrid emitter-antenna coupled systems where electric dipole, quadrupole or magnetic dipole moments are dominant. Experimental angular radiation patterns show striking differences in the emission of resonant and non-resonant magnetic modes excited by local light sources [3]. Finally we present a magneto-electric antenna: by exploiting the interference between magnetic and electric modes we experimentally realize a compact and robust optical antenna for directed photon emission, which outperforms larger, multielement antennas in both bandwidth and directionality.

References

458

[1] AG Curto et al. Unidirectional emission of a Q-dot coupled to a nanoantenna, Science 329, 930 (2010).

[2] TH Taminiau et al. Optical nanorod antennas as cavities for dipolar emitters: sub- & superradiant modes, NanoLett. 11, 1020 (2011).

[3] AG Curto et al. Magnetic Resonance of a Nanoslot Optical Antenna, Submitted.

ImagineNano2013

Oral Near-field patterns in two dimensional arrays of gold nanorods supporting geometric resonances

1

Alan Vitrey 2 L. Aigouy 1 P. Prieto J. M. García-Martín1 and 1 M. U. González alan.vitrey@imm.cnm.csic.es

1

ImagineNano2013

40nm above the structures, as well as in the vertical plane which contains the small axis of the nanorods. Different polarizations of the incident light were used for both far and near field experiments.

Our results show that the collective geometrical response induces a complex redistribution of the nearfield distribution. In fact, we pinpoint that the vertical component of the electric field can play an important role in the resulting field pattern, a significant difference with previous theoretical works that only considered in-plane components [4]. For instance, the z-component is rapidly delocalized when approaching the wavelength of the RA, leading to a characteristic profile of the electric field with intense lobes, as illustrated in Fig. 2. Moreover, we show that the intensity of this component depends on the spectral position of the LSPR in a drastic manner.

Our results offer a deeper insight on the interplay between individual and collective resonances, which can be of interest for tailoring the near field distribution involved into the designing of sensing applications, and more generally, into the 3D electromagnetic shaping of nanostructures

References [1] S. Zou and G.C. Schatz, The Journal of Chemical Physics 121 (2004) 12606.

[2] S. Zou and G.C. Schatz, Chemical Physics Letters 403 (2005) 62.

[3] P. Offermans, M.C. Schaafsma, S.R.K. Rodriguez, Y. Zhang, M. Crego-Calama, S.H. Brongersma, and J. Gómez Rivas, ACS Nano 5 (2011) 5151.

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Arrays of metallic nanoparticles have been found to exhibit attractive properties such as sharp peaks of extinction [1] and field enhancements higher than the ones exhibited by localized surface Plasmon resonance (LSPR) of single nanoparticles [2] These features arise from the coupling with the LSPR and the diffraction orders of the arrays, and can be exploited in different applications such as sensing [3], enhanced Raman scattering, etc.

Therefore, a deeper understanding on these phenomena and the underlying near-field distribution is of interest to enhance the performance of the arrays.

In this work, we have investigated the far and near field responses of two dimensional arrays of gold nanorods on glass by means of extinction spectra (figure 1), scanning near field optical microscopy (SNOM) and numerical simulations using FDTD techniques (the model uses the morphological data obtained from scanning electron and atomic force microscopies). We have fabricated by e-beam lithography a set of arrays of nanorods with different width, length and height (see example in Fig. 1). Every type of nanorod sustains a LSPR in the same range of wavelengths than the laser used for the SNOM measurements (658 nm). As we want to distinguish between the contribution to the near field distribution that is induced by the interaction LSP – array and that produced by the LSP itself, we have chosen different array periodicities in order to place the Rayleigh anomaly (RA) inside or outside the LSPR region, respectively. The near field microscopy has been carried out by exciting the samples in transmission and by probing the near field with a fluorescent particle of 100nm diameter. We have scanned the samples in a horizontal plane about

PPM 2013

IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC), Isaac Newton 8, 28760 Tres Cantos, Spain 2 Laboratoire de Physique et d’Etude des Matériaux, UMR CNRS 8213, ESPCI, 10 rue Vauquelin, Paris 75231, France

[4] A.G. Nikitin, A.V. Kabashin, and H. Dallaporta, Opt Express 20 (2012) 27941.

Figures

Figure 1 (a) SEM picture of an array of nanorods. b) Experimental extinction spectra of the array shown in (a). The vertical dashed line shows the wavelength of a Rayleigh anomaly. Inset: the schema represents the array of nanorods and the definition of the coordinate system. The incident light is polarized along the double arrow labeled Einc.

460

Figure 2 Near-field distribution at a wavelength close to the RA. The zone corresponds to the x-z plane crossing the nanorods on their center. Left: Numerical result. z=0nm is the surface of the substrate. The white dashed rectangles represent the crosssections of the nanorods. Right: Experimental SNOM image which corresponds to the region shown by the green dashed rectangle on the numerical result. On the experimental image, z=0 is actually about 40nm above the nanorods.

ImagineNano2013

Invited Three-dimensional optical laser lithography: No limits?

Martin Wegener

martin.wegener@kit.edu

Three-dimensional (3D) direct laser writing (DLW) has become a commercially available workhorse and can be seen as the 3D counterpart of planar electron-beam lithography. However, DLW was previously subject to seemingly fundamental limitations regarding (i) spatial resolution due to the Abbe diffraction barrier, (ii) accessible sample heights due to finite microscope-lens working distances, and (iii) writing speed. This talk gives an introduction and presents the state-of-the-art. (i) Stimulated-emission-depletion (STED) 3D DLW has recently broken the diffraction barrier [1]. For example, this has enabled the first 3D visiblefrequency polarization-independent invisibility cloak and the first visible-frequency 3D completephotonic-band-gap material. (ii) 3D â&#x20AC;&#x153;dip-inâ&#x20AC;? DLW has enabled the first 3D pentamode mechanical metamaterial.

PPM 2013

Karlsruhe Institute of Technology (KIT), Institute of Applied Physics, Institute of Nanotechnology, and DFG-Center for Functional Nanostructures, 76128 Karlsruhe, Germany

References

ImagineNano2013

461

[1] J. Fischer and M. Wegener, Laser Photon. Rev. 7, 22 (2013).

Invited Active Nanoplasmonics: Loss, Gain and Nonlinearity

Anatoly Zyats

anatoly.zayats@kcl.ac.uk

Department of Physics, Kingâ&#x20AC;&#x2122;s College London Strand, London, WC2R 2LS, United Kingdom

462

Active and tuneable plasmonic components are required for development of integrated photonic circuits, in highdensity data storage applications as well as bio- and chemical sensing in lab-on-a-chip systems, to name a few. Plasmonic crystals, waveguiding components and metamaterials have recently been demonstrated to enhance various active functionalities based on electric, magnetic, acoustic and optical control signals. Amplification of plasmonic signals and dispersion management have also been addressed. All-optical control is especially interesting as it allows achievement of fast response and variety of approaches to be used, including nonlinear response and spontaneous and stimulated emission effects [1].

Other important prospective applications rely on the enhanced nonlinear magneto-optical effects.

In this talk, we will overview new opportunities provided by plasmonic nanostructures for controlling photonic signals using the effects enabled by sub-wavelength field confinement and interaction between plasmonic resonances [2-16].

In addition to conventional intensity and phase modulations, active control of light polarization presents an important alternative. In turn, the polarization can be used as a control and condition the signal. The role of electron and phonon temperature effects will be discussed on the optical response of the nanostructures and it will be shown that their influence depends on the type of coupling between the plasmonic resonances.

We will also discuss nonlinearities originating from free electrons in a metal in specifically tailored nanostructures to enhance second- and thirdorder nonlinearities [2-5]. We will show how to go beyond the brute-force field enhancement effects to achieve the enhanced nonlinear optical response due to the nonlocal properties of the assembly of interacting nanopartcicles. The

loss/gain-induced coupling of plasmonic resonances will also be considered in nonHermitian metamaterials, and its role in controlling polarization of transmitted/reflected light will be shown [15,16].

References [1] M. Kauranen, A. V. Zayats, "Nonlinear plasmonics," Nature Photonics 6, 2012, pp.

737-748.

[2] V.L. Krutyanskiy, E.A. Gan'shina, P. Evans, I.A. Kolmychek, S.V. Lobanov, T.V. Murzina, R. Pollard, A.A. Stashkevich, G.A. Wurtz, A.V. Zayats, "Plasmonic enhancement of the nonlinear magneto-optical response of nickel nanorod metamaterials," Phys. Rev. B 87, 2013, 035116.

[3] G. A. Wurtz, R. Pollard, W. Hendren, G. P. Wiederrecht, D. J. Gosztola, V. A. Podolskiy, A. V. Zayats, "Designed ultrafast optical nonlinearity in a plasmonic nanorod metamaterial enhanced by nonlocality," Nature Nanotech. 6, 2011, pp. 107-111.

[4] P. Ginzburg, A.V. Krasavin, A.V. Zayats, "Cascaded second-order surface plasmon solitons due to intrinsic metal nonlinearity," New J. Phys. 15, 2013, 013031.

[5] P. Ginzburg, A. Krasavin, Y. Sonnefraud, A. Murphy, R. J. Pollard, S. A. Maier, A. V. Zayats, "Nonlinearly coupled localized plasmon resonances: resonant second-harmonic generation," Phys. Rev. B 86, 2012, 085422.

[6] P. Ginzburg, A. V. Zayats, "Linewidth enhancement in spasers and plasmonic nanolasers," Opt. Express 21, 2013, 21472153.

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ImagineNano2013

PPM 2013

463

[7] A. V. Krasavin, Th. Ph. Vo, W. Dickson, P. M. Bolger, A. V. Zayats, "All-plasmonic modulation via stimulated emission of copropagating surface plasmon polaritons on a substrate with gain," Nano Lett. 11, 2011, pp.

2231-2235.

[8] D. Fedyanin, A. V. Krasavin, A. Arsenin, A. V. Zayats, "Surface plasmon polariton amplification upon electrical injection in highly-integrated plasmonic circuits," Nanoletters 12, 2012, pp. 2459– 2463.

[9] A. N. Poddubny, P. A. Belov, P. Ginzburg, A. V. Zayats, Yu. S. Kivshar, "Microscopic model of the Purcell enhancement in hyperbolic metamaterials," Phys. Rev. B 86, 2012, 035148.

[10] A. N. Poddubny, P. Ginzburg, P. A. Belov, A. V. Zayats, Yu. Kivshar, "Tailoring and enhancing spontaneous two-photon emission processes using resonant plasmonic nanostructures," Phys. Rev. A 86, 2012, 033826.

[11] J.-S. Bouillard, S. Vilain, W. Dickson, G. A. Wurtz, A. V. Zayats, "Broadband and broadangle optical antennas based on plasmonic crystals with linear chirp," Sci. Rep. 2, 2012, 829.

[12] Y. Veniaminova, A. A. Stashkevich, Y. Roussigné, S. M. Chérif, T. V. Murzina, A. P. Murphy, R. Atkinson, R. J. Pollard, A. V. Zayats, "Brillouin light scattering by spin waves in magnetic metamaterials based on Co nanorods," Opt. Mater. Expr 2, 2012, pp.

1260-1269.

[13] A. V. Krasavin, A. V. Zayats, "Photonic signal processing on electronic scales: electro-optical fieldeffect nanoplasmonic modulator, "Phys.

Rev. Lett. 109, 2012, 053901.

[14] J.-S. Bouillard, G. A. Wurtz, W. Dickson, D. O'Connor, A. V. Zayats, "Low-temperature plasmonics of metallic nanostructures," Nanoletters 12, 2012, pp. 1561-1565.

[15] P. Ginzburg, A. V. Zayats, "Non-exponential decay of dark localized surface plasmons," Opt. Exp. 20, 2012, pp. 6720-6727.

[16] P. Ginzburg, F. J. Rodríguez Fortuño, A. Martínez, A. V. Zayats, "Analogue of the quantum Hanle effect and polarisation conversion in non-Hermitian plasmonic metamaterials," Nanoletters 12, 2012, pp.

6309–6314.

TNA

2013

Index TNA2013 Contributions Invited

Pag

■ Gabriel Abadal Berini (UAB,Spain) "Energy harvesting from ambient mechanical vibrations and electromagnetic radiations based on MEMS and NEMS devices"

473

■ Jouni Ahopelto (VTT, Finland) Abstrat not provided by the speaker

-

■ Javier Carretero (energiGUNE,Spain) "Carbon nanotubes and other low dimensional carbons for energy harvesting, conversion and storage"

476

■ Luca Gammaitoni (Università di Perugia, Italy) "Toward Zero-Power ICT"

479

■ Didier Gigmes (IRC - UMR 5256, France) "Synthesis of single-ion BAB triblock nanostructurated copolymers as efficient electrolytes for lithium metal batteries"

480

■ Fabian Hartann (University of Wuerzburg, Germany) Abstrat not provided by the speaker

-

■ Florence Lefebvre-Joud (LITEN CEA, France) "Nanomaterial activities at CEA LITEN for low carbon energy technologies development"

483

■ Serge Palacin (CEA Saclay, IRAMIS SPCSI, France) "Functional catalysts for hydrogen production and uptake, and oxygen reduction based on modified carbon nanotubes networks"

492

■ Michael Silver (American Elements, USA) "Recent Research & Development at American Elements Using Nanotechnology in Fuel Cells"

496

■ Patrice Simon (Université Paul Sabtier, France) "Ion confinement in carbon nanopores - application to supercapacitors"

497

■ Bjorn Sothmann (Université de Genève, Switzerland) "Powerful and efficient energy harvesting with resonant-tunneling quantum dots"

498

■ Clivia M. Sotomayor Torres (Catalan Institute of Nanotechnology, Spain) "Phonon Engineering for Heat Transport Control"

500

■ Helios Vocca (Nipslab, University of Perugia, Italy)

ImagineNano2013

-

467

Abstrat not provided by the speaker

Oral

Pag

■ Sweta Bhansali (Catalan Institute of Nanotechnology, Spain) 474

"Metal-oxide thin films as high efficiency thermoelectric materials"

■ Emigdio Chávez (Catalan Institute of Nanotechnology, Spain) "Thermal properties of silicon ultra-thin membranes: A theoretical and experimental approach"

477

■ Wen-Yin Ko (National Chung-Hsing University, Taiwan) "Solvothermal-Processed Spinel-type Manganese Oxide Microspheres and Their Improved Supercapacitive Properties"

482

■ Wei-Shun Liao (National Cheng Kung University, Taiwan) "Free carrier screening effects on piezotronic properties and piezoelectric nanogenerators of GaN nanowire arrays"

485

■ Lifeng Liu (International Iberian Laboratoy (INL), Portugal) "Nickel foam supported MnO2 nanosheet arrays for electrochemical energy storage"

487

■ Javier Martínez Rodrigo (Universidad Politécnica de Madrid, Spain) 488

"3D graphene supercapacitor for energy applications"

■ Cécile Mayousse (CEA / LITEN, France) "Transparent and flexible electrodes based on metallic nanowire networks for optoelectronic devices"

490

■ Mathieu Pinault (CEA Saclay, France) "Nanocomposites based on electronically conducting polymers / aligned carbon nanotubes for electrochemical storage in liquid media"

493

■ Miguel Ribeiro (CeNTI - Centre for Nanotecnology and Smart Materials) "Low energy consumption electrochromic systems based on metallo-organic polymers"

495

■ Amin Tabatabaei Mohseni (Istanbul Technical University, Turkey) 501

"Photochromic electrospun fibers based on tungsten hexachloride"

■ Marko Tadjer (Universidad Politécnica de Madrid, Spain) 502

"MnO2-based electrochemical supercapacitors on flexible carbon substrates"

■ Marta Urdanpilleta (UPV/EHU, Spain) "Relation between surface structure and performance of bulk heterojunction organic solar cells"

504

■ Fei Yao (Institute of Basic Science, Sungkyunkwan University, Korea)

468

"Silicon-Coated Carbon Nanofiber Mat for Anode of Lithium Ion Battery"

505

ImagineNano2013

Index TNA2013 Contributions Alphabetical Order I:Invited / O: Oral

Pag

■ Gabriel Abadal Berini (UAB,Spain) "Energy harvesting from ambient mechanical vibrations and electromagnetic radiations based on MEMS and NEMS devices"

I

473

I

-

O

474

I

476

O

477

I

479

I

480

I

-

O

482

I

483

O

485

O

487

O

488

O

490

I

492

O

493

■ Jouni Ahopelto (VTT, Finland) Abstrat not provided by the speaker

■ Sweta Bhansali (Catalan Institute of Nanotechnology, Spain) "Metal-oxide thin films as high efficiency thermoelectric materials"

■ Javier Carretero (energiGUNE,Spain) "Carbon nanotubes and other low dimensional carbons for energy harvesting, conversion and storage"

■ Emigdio Chávez (Catalan Institute of Nanotechnology, Spain) "Thermal properties of silicon ultra-thin membranes: A theoretical and experimental approach"

■ Luca Gammaitoni (Università di Perugia, Italy) "Toward Zero-Power ICT"

■ Didier Gigmes (IRC - UMR 5256, France) "Synthesis of single-ion BAB triblock nanostructurated copolymers as efficient electrolytes for lithium metal batteries"

■ Fabian Hartann (University of Wuerzburg, Germany) Abstrat not provided by the speaker

■ Wen-Yin Ko (National Chung-Hsing University, Taiwan) "Solvothermal-Processed Spinel-type Manganese Oxide Microspheres and Their Improved Supercapacitive Properties"

■ Florence Lefebvre-Joud (LITEN CEA, France) "Nanomaterial activities at CEA LITEN for low carbon energy technologies development"

■ Wei-Shun Liao (National Cheng Kung University, Taiwan) "Free carrier screening effects on piezotronic properties and piezoelectric nanogenerators of GaN nanowire arrays"

■ Lifeng Liu (International Iberian Laboratoy (INL), Portugal) "Nickel foam supported MnO2 nanosheet arrays for electrochemical energy storage"

■ Javier Martínez Rodrigo (Universidad Politécnica de Madrid, Spain) "3D graphene supercapacitor for energy applications"

■ Cécile Mayousse (CEA / LITEN, France) "Transparent and flexible electrodes based on metallic nanowire networks for optoelectronic devices"

■ Serge Palacin (CEA Saclay, IRAMIS SPCSI, France) "Functional catalysts for hydrogen production and uptake, and oxygen reduction based on modified carbon nanotubes networks" "Nanocomposites based on electronically conducting polymers / aligned carbon nanotubes for electrochemical storage in liquid media"

ImagineNano2013

469

■ Mathieu Pinault (CEA Saclay, France)

I:Invited / O: Oral

Pag

■ Miguel Ribeiro (CeNTI - Centre for Nanotecnology and Smart Materials) "Low energy consumption electrochromic systems based on metallo-organic polymers"

O

495

I

496

I

497

I

498

I

500

O

501

O

502

O

504

I

-

O

505

■ Michael Silver (American Elements, USA) "Recent Research & Development at American Elements Using Nanotechnology in Fuel Cells"

■ Patrice Simon (Université Paul Sabtier, France) "Ion confinement in carbon nanopores - application to supercapacitors"

■ Bjorn Sothmann (Université de Genève, Switzerland) "Powerful and efficient energy harvesting with resonant-tunneling quantum dots"

■ Clivia M. Sotomayor Torres (Catalan Institute of Nanotechnology, Spain) "Phonon Engineering for Heat Transport Control"

■ Amin Tabatabaei Mohseni (Istanbul Technical University, Turkey) "Photochromic electrospun fibers based on tungsten hexachloride"

■ Marko Tadjer (Universidad Politécnica de Madrid, Spain) "MnO2-based electrochemical supercapacitors on flexible carbon substrates"

■ Marta Urdanpilleta (UPV/EHU, Spain) "Relation between surface structure and performance of bulk heterojunction organic solar cells"

■ Helios Vocca (Nipslab, University of Perugia, Italy) Abstrat not provided by the speaker

■ Fei Yao (Institute of Basic Science, Sungkyunkwan University, Korea)

470

"Silicon-Coated Carbon Nanofiber Mat for Anode of Lithium Ion Battery"

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A b s t r ac t s Alphabetical order

TNA 2013

Invited Energy harvesting from ambient mechanical vibrations and electromagnetic radiations based on MEMS and NEMS devices

Gabriel Abadal

Departament d’Enginyeria Electrònica. Universitat Autònoma de Barcelona.

08193-Bellaterra (Barcelona). SPAIN

electret technology in a microcantilever based non-linear vibration energy harvester”, To be published in Appl. Phys. Lett. (2013).

Figures

TNA 2013

Microelectromechanical systems (MEMS) have demonstrated to be a suitable technology to implement the transducer element of energy harvesting devices at the micrometer scale. This is so especially when mechanical vibration sources are involved. However, MEMS based realizations of vibration energy harvesters (VEH) have to overcome several intrinsic limitations related to the mismatch between their natural resonance frequency with the characteristic frequency of the vibration source, as well as those related to the low energy that a microsystem can extract from the ambient.

In this talk we are going to show some strategies that are oriented to treat such limitations. From one hand we are going to present a non-linear vibration energy harvester (NLVEH) implemented on an AFM triangular cantilever. Bistable nonlinearity is induced by means of one electret locally charged at the free end of the AFM cantilever and another at a closely placed counter electrode1.

Experimental results show (figure 1) that an accurate control of the distance between the cantilever and the counter electrode (d), allows optimizing the rms value of the cantilever deflection when the system is excited with a certain intensity of pink noise.

On the other hand, proof of concept devices of micro-opto-electromechanical systems (MOEMS) based energy harvesters, which have been designed to extract energy from electromagnetic radiation sources in the radiofrequency (RF) range and in the IR optical range, will be also presented.

Figure 1: Experimental (symbols) and simulated (lines) results for the rms value of the AFM cantilever deflexion as a function of cantilever – counter electrode distance, d. The intensity of the excitation noise is Frms=4nN.

References

ImagineNano2013

473

[1] M. López-Suárez, J. Agustí, F. Torres, R. Rurali, G. Abadal. “Inducing bistability with local

Oral Metal-oxide thin films as high efficiency thermoelectric materials 1

Sweta Bhansali

Catalan Institute of Nanotechnology, Campus de la UAB, 08193 (Bellaterra) Barcelona, Spain Centre d’Investigació en Nanociencia i nanotecnología (CIN2), Campus de la UAB, 08193 (Bellaterra) Barcelona, Spain 3 Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Spain 4 Thermoelectrics Research Group, Instituto de Microelectronica de Madrid, CSIC, Isaac Newton, 8 PTM, 28760 Tres Cntos (Madrid), Spain 5 Catalan Institute for Research and Advanced Studies ICREA, 08010 Barcelona, Spain 6 Dept. of Physics, Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona), Spain 7 CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia (FCT), Universidade Nova de Lisboa and CEMOP-UNINOVA,Portugal 2

474

The continuous quest for advanced technologies and materials towards clean and renewable energy consumption model has triggered a large amount of research activities.

In particular, thermoelectricity represents a good example of smart heat management, e.g. the waste heat production from a primary process is converted into usable energy. A large figure-of-merit (ZT=S2σ/k) is usually the key parameter to obtain a high thermoelectric efficiency. To achieve this, two strategies are usually followed: i) decreasing the thermal conductivity (k), and 2) Increasing the power factor (S2σ; S:Seebeck coefficient, σ:electrical conductivity). While the former is usually achieved by enhancing phonon scattering by nanostructuring [1,2], the later is achieved by modification of the electronic density of states [3].

Metal-oxides present many interesting properties such as their high thermal and chemical stability, which make them ideal candidates for high temperature thermoelectric applications.

However, due to the poor electrical conductivity their prospect as thermoelectric materials has been overlooked. Recently, the observation of enhanced electrical conductivity and Seebeck coefficient in layered metal oxide such as NaCo2O4 and Ca3CoO9 [4], has renewed the interest in this type of materials. In this case, a strongly correlated electron layer of CoO2 serves as the electronictransport layer and the Na+ ions act as phonon scatterers limiting the thermal conductivity. These materials lead to a figure of merit ZT as high as 0.8 at 1000K [4], which is comparable to a state-ofthe-art thermoelectric such as Bi2Te3. Furthermore, the low mobility problem was also recently overcame by Ohta and co-workers[5] by applying the well-established concept of the 2-dimensional electron gas formation to increase the electrical

1

W. Khunsin1, J. S. Reparaz1 J. Roqueta2, J. Santiso2 P. O. Vaccaro3,5, M. Garriga3 M. I. Alonso3, A. R. Goñi3,5 B. Abad Mayor4, P. Díaz-Chao4 M. Martin-Gonzalez4,J. Loureiro1,5,6 I. Ferreira1,5,6 and C. M. Sotomayor Torres1,5,6

conductivity and the Seebeck coefficient of the oxides.

In this contribution, we will present a comprehensive study of the thermoelectric properties of metal-oxides. We will mainly focus on Nb-doped SrTiO3 thin layers as function of film thickness, temperature, and doping level. Figure 1 shows the thermoelectric characterization of lightly (2%) Nb doped SrTiO3 thin films prepared by pulsed laser deposition as a function of the film thickness. A large enhancement of the Seebeck coefficient as well as the power factor is observed for the thinner films, which arises from the formation of a 2D electron gas at the interface between the SrTiO3 thin film and the LaAlO3 substrate. On the contrary, the thermal conductivity of the layers exhibits a 2 to 3-fold reduction with respect to the bulk values arising from the combined effect of boundary scattering with oxygen deficiency within the layers.

Furthermore, the ZT values exhibit a similar behaviour as the power factor with values as high as ZT = 0.625 at 300K for the thinner layers. Finally, figure 1 also displays high-resolution TEM images of the layers. In figure 2 we show the thermoelectric properties for V2O5 and ZnO thin layers doped with different metals (Ag, Au, Pt, Cr).

In this case the figure of merit of these materials is comparable to that observed for the thicker SrTiO3 samples. A comparison between these materials systems will be presented pointing out their relative advantages as good thermoelectrics for future energy conversion applications.

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References [1] Jinyao.Tang et. al, Nano Lett. 10, 4279 (2010).

[2] Jen-kan Yu et al, Nature Nanotechnology 5, 718 (2010).

[3] M. S. Dresselhaus et. al, Phys. Rev. B 47, 16631 (1993).

[4] I. Terasaki et. al, Phys. Rev. B 56 (1997) R12685.

[5] S. Ohta et. al, Appl. Phys. Lett. 87 (2005) 092108.

TNA 2013

Figures

Figure 1: Thermoelectric properties of Nb-doped SrTiO3 thin films on LaAlO3 substrate as a function of the film thickness. (a) Seebeck coefficient and thermal conductivity (b) Power factor (c) ZT (Figure of merit) (d, e) High-resolution transmission electron microscopy images of a thin film.

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Figure 1: Thermoelectric properties of V2O5 and ZnO thin flims for different dopants: Au, Ag, Pt, Cr. (a) Temperature dependent thermal conductivity, (b) ZT as a function of the different materials.

Invited Carbon nanotubes and other low dimensional carbons for energy harvesting, conversion and storage

Javier Carretero-González

CIC EnergiGUNE, Albert Einstein 48 - ED. CIC, 01510 Miñano, Alava, Spain

In this talk I will show a brief view of three different applications related with energy in which low dimensional carbons like carbon nanotubes and graphene nanoribbons [1] are involved. The first one is related with the capture of waste heat produced in chemical industry at relatively low temperature (≤ 130 °C) by using carbon nanotubes in both electrodes (positive and negative) in thermocells. [2] The second one provides a new procedure for making nanotube electrodes for energy storage applications by using a biscrolling procedure of nanotube sheets from spinnable nanotube forests. [3] Generically applicable biscrolling methods are demonstrated for producing yarns comprising up to 99 wt % of otherwise unspinnable nanopowders or nanofibers that remain highly functional. These methods utilize the strength and electronic connectivity of down to 1 wt % of carbon nanotube sheet that is helically scrolled in the yarn. This new technology is used to make yarns of graphene ribbons, high performance battery materials and catalytic nanofibers for fuel cells. The last part of this talk will show the latest developments on nanotechnology research for electrochemical energy storage (supercapacitors and alkaly-ion batteries) that we are carrying out in CIC energiGUNE.

Electrochemical Cell, Renchung Hu, et al. Nano Lett., 10, 2010, 838-846.

[3] Biscrolling Nanotube Sheets and Functional Guests into Yarns, Lima, et al. Science 7 January 2011: 51-55.

Figures

Figure 1: (A) Cyclic voltammogram of a 95% LiFePO4@MWNT4,6 biscrolled yarn between 2.5 and 4.2 V at 0.1 mV/s in an electrolyte containing 1 M LiPF6 in a 1:2:3 by volume mixture of propylene carbonate, ethylene carbonate, and dimethylcarbonate, respectively. (B) SEM micrograph of the surface of a 94% LiFePO4@MWNT2,1 biscrolled yarn, showing LiFePO4 particles contacted by a web of MWNTs.

References

476

[1] Oriented Graphene Nanoribbon Yarn and Sheet from Aligned Multi-Walled Carbon Nanotube Sheets, Javier Carretero-Gonzalez et al., Adv. Mater. 8 November, 2012, 56955701.

[2] Harvesting Waste Thermal Energy Using a Carbon-Nanotube-Based Thermo-

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Oral Thermal properties of silicon ultra thin membranes: A theoretical and experimental approach 1

Catalan Institute of Nanotechnology (ICN), 08193 Bellaterra, Spain Dept. of Physics, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA 4 .VTT Technical Research Centre of Finland, PO Box 1000, 02044 VTT, Espoo, Finland 5 Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain 2

Emigdio Chávez

1, 2

J.S. Reparaz1, J. Cuffe3 J. Gomis-Bresco1, M. R. Wagner1 A. Shchepetov4, M. Prunnila4 J. Ahopelto4, F. Alzina1 and C. M. Sotomayor Torres1, 2, 5

echavez@icn.cat

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was also studied using state-of-the-art ultrafast pump-probe, i.e. asynchronous optical sampling (ASOPS). We have observed that the lifetime of the first-order dilatational mode decreases significantly from ∼ 4.7 ns to 5 ps with decreasing membrane thickness from ∼ 194 to 8 nm [7].

Finally, the thermal conductivity of the membranes was investigated using a novel contactless technique known as Raman thermometry. We have found that the thermal conductivity of the membranes gradually reduces with their thickness, reaching values as low as 9 W/mK for the thinnest membrane.

In order to account for the observed thermal behaviour of the ultra-thin membranes we have developed different theoretical approaches to explain the size dependence of the dispersion relations based on an elastic continuum approach, Debye model and fitting models. The size dependence of the lifetimes was modelled considering intrinsic phonon-phonon processes and extrinsic phonon scatterings. The thermal conductivity was modelled using a modified 2D Debye approach and Srivastava-Callaway-Debye model.

References [1] A. Majundar, Science, 303 (2004), 777.

[2] R. Venkatasubramanian, E. Siivola, T. Colpitts and B. O’Quinn, Nature, 413 (2001), 597.

[3] A.I. Boukai, Y. Bunimovich, J. Tahir-Kheli, J.-K. Yu, W.A. Goddard and J.R. Heath, Nature, 451(2008).

[4] G.D. Mahan and H.B. Lyon, J. Appl. Phys., 76(1994), 1899.

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A deep understanding of heat transport in lowdimensional semiconductor structures is a topic of increasing research activities driven by the need for a more energy conscious society. This is motivated in part from the increasing importance of thermal management as a consequence of the large power densities resulting from the continuous miniaturization of electronics components. Moreover, the quest for enhanced thermoelectric properties generally requires large values of the figure of merit ZT [1]. Recent experimental and theoretical reports point to an enhancement of the figure of merit in thin films [2], nanowires [3] and superlattices [4] [5], primarily as a result of the decrease of the thermal conductivity compared to the bulk counterpart, without a corresponding decrease in electrical conductivity. The reduced dimensions lead to the confinement of acoustics modes and the discretization of their spectrum, resulting in the modification of phonon density of states and dramatic decrease of group/phase velocity [6] and phonon lifetime [7].

In the present work we study theoretically and experimentally the thickness-dependence of the thermal properties of Silicon membranes with thicknesses ranging from 9 to 1500 nm. We investigate the dispersion relations and the corresponding modification of the phase velocities of the acoustic modes, which are mostly responsible for the heat transport, using inelastic Brillouin light scattering spectroscopy. A reduction of the phase/group velocities of the fundamental flexural mode by more than one order of magnitude compared to bulk values was been observed and is theoretically explained [6]. In addition, the lifetime of the coherent acoustic phonon modes with frequencies up to 500 GHz

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[5] D. Broido and T. Reinecke, Phys. Rev. B, 51(1995), 13797.

[6] J. Cuffe, E. Chávez, A. Shchepetov, P.-O. Chapuis, E. H. El Boudouti, F. Alzina, T. Kehoe, J. Gomis-Bresco, D. Dudek, Y. Pennec, B. Djafari-Rouhani, M. Prunnila, J. Ahopelto and C. M. Sotomayor Torres, Nano Lett., 12(2012), 3569.

[7] J. Cuffe, O. Ristow, E. Chávez, A. Shchepetov, P-O. Chapuis, F. Alzina, M. Hettich, M. Prunnila, J. Ahopelto, T. Dekorsy and C. M. Sotomayor Torres, Phys. Rev. Lett., (2013) Accepted.

[8] J. Cuffe, Phonon-Photon Interactions in Nanostructures, Ph.D. Thesis, University College of Cork, 2011.

Figures

Figure 1: (a) Dispersion curves plotted in terms of the phase velocity as a function of dimensionless wavevector (q//·d) for membranes with thickness values ranging from 400 to 7.8 nm. Inset: Optical microscope image of the 30 nm Si membrane. (b) Magnified image of the highlighted region in showing data for membranes of thickness from 7.8 to 31.9 nm. The linear relationship observed is a direct result of the quadratic dispersion relation. A phase velocity down to approximately 300 ± 40 m/s is recorded for the 7.8 nm membrane [6].

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Figure 2: (a) Experimental and theoretical phonon lifetime in freestanding silicon membrane. Red dots: experimental data [7]. Green line: extrinsic boundary scattering processes. Blue-dotted line intrinsic three-phonon normal scattering processes. Black-dashed line: total contribution, calculated through Matthiessen’s rule. (b) Experimental and theoretical thermal conductivity. Red dots: Experimental thermal conductivity measured by transient thermal gradient technique [8]. Black dots: Experimental thermal conductivity measured by Raman thermometry. Blue line Theoretical prediction.

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Invited Toward Zero-Power ICT

Luca Gammaitoni

NiPS Laboratory, Physics Department, University of Perugia and INFN Perugia, Via A. Pascoli, 1, 06123 Perugia, IT

harvesting), Contemporary Physics, 53, 2, p.

119-135, 2012.

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It is a common understanding that ICT is the key engine of growth in modern society. Most importantly ICT is becoming strategic to improve energy efficiency by managing energy demand and use. The energy consumption and carbon dioxide emission from the expanding ICT use, however, is unsustainable. New methods are required to make ICT technology more energy efficient but also the development of new self-powered, energyharvesting technologies that would enable microand nano-scale systems that consume ZEROPOWER through the harvesting of waste energy from the environment are required. Such technologies provide an opportunity for Europe to lead and generate significant economic benefit whilst simultaneously addressing climate change, healthcare and manufacturing efficiency benefits.

Developing ZEROPOWER energy harvesting technology will be key for Europe to meet many of the Europe 2020 targets [1].

In this talk we will briefly address the two sides of the ICT-Energy problem: the decrease of energy dissipation in present ICT devices and the increase of energy efficiency in harvesting technologies [2].

We need to solve these two problems in order to bridge the gap between energy demand and energy request in mobile ICT devices. Both tasks require advances on the very same scientific topic: the management of energy transformation processes at nanoscale.

luca.gammaitoni@nipslab.org

References

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[1] ZEROPOWER Strategic Research Agenda, Nanoenergy Letters, 4, p.6, 2012.

[2] L. Gammaitoni, There's plenty of energy at the bottom (micro and nano scale nonlinear noise

Invited Synthesis of single-ion BAB triblock nanostructurated copolymers as efficient electrolytes for lithium metal batteries

Didier Gigmes

didier.gigmes@univ-amu.fr

Aix Marseille UniversitĂŠ, CNRS, Institut de Chimie Radicalaire 13397, Marseille cedex 20, France

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The development of alternative transportation modes such as electric or hybrid vehicles, has become a key need for a sustainable long term development [1]. In this context, the increase of energy density for the battery systems is crucial and imposes necessary to explore original strategies for both the active electrode materials and electrolyte [2,3]. Among the different systems, battery technology based on a lithium metal anode would be particularly attractive notably in combination with Li-S and Li-air systems [4].

Unfortunately, the use of lithium metal associated with liquid electrolyte, led to safety problems due to a possible irregular metallic lithium electrodeposits during the recharge. In some cases, this phenomenon could result in dendrite formation responsible for dramatic explosion hazards. The use of a solid polymer electrolyte (SPE), could solve most of the safety issues encounter with liquid electrolyte. However, the development of SPE has been hampered by two hurdles i/ the inability to design a SPE that exhibits both a high ionic conductivity and good mechanical properties and ii/ during battery operation, the motions of lithium ions carry only a small fraction of the overall ionic current which leads to the formation of strong concentration gradient resulting in undesired effects like favored dendritic growth [5] and limited energy density especially when power increases.

In recent years, increasing research efforts have been focused on SPE made from block copolymers such BAB, where A represents an ionic conductor typically poly(ethylene oxide) (PEO) block and B a polymer providing the mechanical strength.

Indeed, thank to their ability to self-assemble at the nano-scale, block copolymers represent a unique class of materials allowing the combination of different properties in a single material. The

main advantage of the block copolymers is based on the covalent attachment of two different polymers, thus avoiding the unwanted macrophase separation when the blocks are immiscible.

In this presentation we will demonstrate the potential of the Nitroxide Mediated Polymerization technique to prepare a series of block copolymers fulfilling the specific criteria of solid polymer electrolytes films designed for lithium metal battery. More particularly, we will present the synthesis of a series of new type of BAB nanostruturated symmetric triblock copolymers with an A block consisting of a linear poly(ethylene oxide) (PEO) as a template for lithium ion conduction, and a B block consisting of poly(4-styrene sulfonyl(trifluoromethylsulfonyl)imide) lithium salt.

The conductivity of these copolymers is almost one order of magnitude higher then that of the state of the art for such materials (1.310-5 Scm-1 at 60°C) combined with a lithium ion transport number close to unity. Moreover the mechanical strength is drastically improved and the electrochemical window stability is extended to more than 5 V. The battery tests show that the power performances and cycling are outstanding particularly at 60°C which makes these materials highly attractive for next battery generation [6].

References [1] J. Tollefson, Nature, 456 (2008) 436-440.

[2] F. Cheng, J. Liang, Z. Tao, J. Chen, Advanced Materials, 23 (2011) 1695-1715.

[3] M. Armand, J-M Tarascon, Nature, 451 (2008) 652-657.

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[4] P. G. Bruce, S. A. Freunberger, L. J. Hardwick, JM. Tarascon, Nature Materials, 11 (2012) 1929.

[5] J-N Chazalviel, Physical Review A, 42 (1990) 7355-7367.

[6] R. Bouchet, S. Maria, R. Meziane, A. Aboulaich, L. Lienafa, J.-P. Bonnet, T. N. T. Phan, D. Bertin, D. Gigmes, D. Devaux, R. Denoyel, M. Armand, Nature Materials (2013) accepted.

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Oral Solvothermal-Processed Spinel-type Manganese Oxide Microspheres and Their Improved Supercapacitive Properties

Wen-Yin Ko L. - J. Chen Y. - H. Chen and K. - J. Lin*

kjlin@dragon.nchu.edu.tw wininnko@gmail.com Department of Chemistry, National Chung-Hsing University, 250 Kuo Kuang Rd., Taichung 402, Taiwan R.O.C.

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stability and the potential application in supercapacitors. In addition, the MS-MnO2 with highly giant cavity through post-annealing treatment can be obtained, which is beneficial for the electrolyte access to the active material, useful for the application in energy storage devices, recharge lithium batteries, photovoltaic devices, solar cells and electrochemical sensors.

References [1] P. Simon, Y. Gogotsi, Nat. Mater., 7 (2008) 845.

[2] O. Ghodbane, J.-L. Pascal, F. Favier, ACS Appl.

Mater. Interfaces, 1 (2009) 1130.

[3] S. Devaraj, N. Munichandraiah, J. Phys. Chem.

C, 112 (2008) 4406.

[4] Y. Xue, Y. Chen, M.-L. Zhang, Y.-D. Yan, Mater.

Lett., 62 (2008) 3884.

Figures 1.5 1.0

Current / Ag-1

Oxide supercapacitors, with advantages of high power density, rapid charge-discharge rates, and long cycle life, have been considered as the promising energy storage devices.[1] Among several materials, manganese dioxide with 3D spinel phase has attracted extensive interest as an appealing electrode material for supercapacitors due to its capability to offer more electrolyte transport paths for the electrons transfer and protons/cations diffusion, which allows enhanced charge transport efficiency through the electrodes during charge/discharge process and leads to good supercapacitive performances.[2] However, the most common strategy to fabricate spinel MnO2 is complicated and difficult to obtain products with high purity and great quality. In our work, MnO2 microspheres (MS-MnO2) with spinel phase have been successfully synthesized by a fast and costeffective one-step solvethermal route in the presence of tetraethyl ammonium bromide surfactant as the template. The electrochemical performances of the MS-MnO2 for supercapacitor device applications were investigated by cyclic voltammetry and galvanostatic charge-discharge measurements through a three electrode system in neutral 1M Na2SO4 electrolyte. These obtained results showed that the MS-MnO2 exhibits good specific capacitance (SC) of ~ 190 F/g which was approximately five times higher than that of the commercial β-MnO2 based device (~36 F/g) and also competitive with that of other reported spinel MnO2 materials including slightly truncated nanoparticles (21 F/g at 20 mV/s),[3] interconnect nanofibers (241 F/g at 5 mV/s),[2] and particles with polyhedral shape (53 F/g at 10 mA/cm2).[4] Besides, with excellent SC retention of ~100% and Coulombic efficiency of ~95 % after 1000 cycles at 1 A/g, the as-synthesized spinel MS-MnO2 materials can be suggested its excellent long-term

â&#x20AC;&#x201D; MS-MnO2 â&#x20AC;&#x201D; Commercial MnO2 --- Carbon black --- Pure Ni film

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Invited Nanomaterial activities at CEA LITEN for low carbon energy technologies development

Florence Lefebvre-Joud F. Lambert H. Burlet and S. Mailley

florence.lefebvre-joud@cea.fr

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of an additional layer between the electrode and the electrolyte upon cycling (Figure 1) [1].

Horizontal carbon nanotubes (CNT) interconnections with realistic size (50nm diameter 13 and 20 Âľm lengh) and density (close to 10 cm-2) have been produced, integrated and tested electrically. The line resistivity is two orders of magnitude higher than copper which is among the best values ever published [2-4].

Currently available transparent electrodes for photovoltaic application suffer from major limitations like costly fabrication process and brittleness. An innovative technology based on random networks of metallic nanowires has been developed which involves a highly flexible and lowcost material with performances similar to the ITO reference. These electrodes have been used to fabricate flexible transparent capacitive touch sensors for demonstrating their potential [5,6].

Mono-like silicon production merges the two main silicon manufacturing growth processes for photovoltaic applications, the Czochralski monocrystalline and the directional multicrystalline solidifications.

This technology combines the low O2 concentration and high productivity of the multi-crystalline wafers with the good crystalline and electrical quality of the mono-crystalline <100> oriented wafers.

Successfully P- and N-type <100> oriented industrial 450 kg ingots were produced with more than 95% <100> controlled oriented areas paving the way for low cost and high efficiency silicon solar cells [7].

To understand degradation mechanisms occurring in Solid Oxide Cells, an original approach has been implemented that combines high technology characterization techniques (Synchrotron X-ray nano-holo-tomography and FIB-SEM) with a multi-

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CEA LITEN, the Laboratory of Innovations for New Energies Technologies and Nanomaterials, located in Grenoble, is part of CEA, a French Governmental Research Organization devoted to both fundamental and industrial R&D in the field of energy, information and health technologies and defence. The activities of LITEN are structured around the production, storage and uses of energy with specific emphasis given to renewable energy sources such as solar energy or biomass, energy efficiency and advanced materials for energy application.

In this context the development of nanomaterials aims at increasing material efficiency, durability and safety, at reducing costs and environmental impact by reducing or even substituting toxic or rare metals. The approach of LITEN covers the entire development chain from the raw materials specification and synthesis, their processing, to their integration and test in full scale prototype.

For that purpose several technological R&D platforms have been developed that allow either advanced characterisation of nanostructures or full scale production and prototyping.

Several examples of such integrated approach are given in the field of nanomaterial developments for high energy batteries, for fuel cell catalysts without noble metals, for high durability solid oxide cells, for low cost carbon conductors, and for and for increased safety of hydrides tank.

Layered Li(Li,Mn,M)O2 are very promising positive electrode materials for high energy Li-ion batteries, however, upon cycling their complex structure undergo evolutions that affect the electrode performance. Atomic scale evolutions in the layered oxide have been studied by diffraction & HRSTEM experiments highlighting the formation

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CEA LITEN, 17 rue des martyrs, 38054 Grenoble Cedex 9, France

scale model of electrode materials. Severe nickel agglomeration in Ni-YSZ cermet electrode has been shown to upon electrolysis operation (Figure 2). The associated decrease of electrochemical active sites has been quantified as well as its impact on the decrease of the cell performance [810]

Figures

References

Figure 1: Atomic scale evolutions in the layered oxide have been studied by diffraction & HRSTEM experiments highlighting the formation of an additional layer between the electrode and the electrolyte upon cycling [1].

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[1] A. Boulineau, L. Simonin et al., Chem. Mater.

24 (2012) 3558.

[2] J. Dijon, H. Okuno, M. Fayolle, T. Vo, J. Pontcharra, D. Acquaviva, D.Bouvet, A. M. Ionescu, C. S. Esconjauregui, B. Capraro, E. Quesnel, J. Robertson, IEDM (2010), p334.

[3] A.Ionescu, J.Dijon, J.Robertson Invited article IEEE microwave magazine 2011, dec 2011 p4250.

[4] J. Dijon Invited paper MRS spring Meeting San Francisco 2013.

[5] C. Celle, C. Mayousse, E. Moreau, H. Basti, A. Carella, J.P. Simonato, Nano Research, 5(6), 2012, 427–33.

[6] J.P. Simonato , E-Nano Newsletter, 24, 2011, 57-9.

[7] A. Jouini, Progress in Photovoltaïcs, 20 (2012) 735–746.

[8] P. Bleuet, P. Gergaud, L. Lemelle, R. Tucoulou, P. Cloetens, J. Susini, G. Delette, A. Simionovici, TrAC, 29 (2010) 518.

[9] J. Villanova, J. Laurencin, P. Cloetens, P. Bleuet, G. Delette, H. Suhonen, F. Usseglio, Journal of Power Sources, submitted.

[10] J. Laurencin, R. Quey, G. Delette, H. Suhonen, P. Cloetens, P. Bleuet, Journal of Power Sources, 198 (2012) 182.

Figure 2: Comparison of the microstructure of the H2 electrode before (left) after (right) operation revealed by XRay nano-holotomography and showing strong Ni coarsening and TPB length decrease.

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Oral

Wei-Shun Liao 1 N. - J. Ku 1 C. - H. Wang and 1,2,3,4 C. - P. Liu

1

cpliu@mail.ncku.edu.tw

Department of Materials Science and Engineering, National Cheng Kung University, No.1, University Road, Tainan City 701, Taiwan 2 Institute of Microelectronics, National Cheng Kung University, No.1, University Road, Tainan City 701, Taiwan 3 Advanced Optoelectronics Technology Center, No.1, University Road, Tainan City 701, Taiwan 4 Center for Micro/Nano Science and Technology,No.1, University Road, Tainan City 701, Taiwan

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increase from 3.7 nA to 8.4 nA with strain at -4V bias and decrease from 1.12 nA to 0.04 nA at +7V bias at the Pt and Ag side, respectively, for the Sidoped GaN NWs. The lnI-V1/4 curves derived from the I-V curves are fairly linear as shown in Figure 3(b), indicating that the thermionic emission diffusion model is the dominant carrier transport process and could be applied to calculate the SBH change from the I-V characteristics. The change of SBH is increased by 75 meV with normal force 3nN for undoped NW. However in the doped GaN NW, the change of SBH is increased by 65 meV with the same force. Apparently, due to the screening effect, external forces can generate higher piezo-field for undoped GaN by piezotronic effect. In conclusion, GaN NWs based piezoelectric nanogenerators have been demonstrated. We investigate the influence of carrier concentration on the energy harvesting and piezotronic effect of doped and Si-doped GaN NWs by AFM. The results can help design high performance piezoelectric nanogenerators and piezotronic devices in the future.

References [1] Z.L. Wang, J.H. Song, Science 312 (2006) 242246.

[2] C.T. Huang, J.H. Song, W.F. Lee, Y. Ding, Z.Y. Gao, Y. Hao, L.J. Chen, Z.L. Wang, Journal of the American Chemical Society 132 (2010) 4766-4771.

[3] N.J. Ku, J.H. Huang, C.H. Wang, H.C. Fang, C.P. Liu, Nano Letters 12 (2012) 562-568.

[4] Y.S. Zhou, K. Wang, W.H. Han, S.C. Rai, Y. Zhang, Y. Ding, C.F. Pan, F. Zhang, W.L. Zhou, Z.L. Wang, Acs Nano 6 (2012) 6478-6482.

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With the advent of global warming and energy crises, developing nanomaterial technologies into various nanodevices for energy harvesting has attracted a lot of attentions recently. Of which, nanogenerators by taking advantage of piezoelectric properties of nanowires (NWs) such as wurtzite compound semiconductors of ZnO [1], GaN [2], InN [3] and CdSe [4] can convert mechanical energy into electricity efficiently.

When a GaN NW is bent by an atomic force microscopy (AFM) tip, an asymmetric strain is produced across the width of the NW. The output current is generated when the tip contacts the stretched side (negative piezoelectric potential side) of the NW as the working principle of a nanogenerator [1]. The key factors to the current generation process include the Schottky contact between metal electrode and GaN NWs and piezopotential created in NWs [5]. In order to deeply understand the role of the piezopotential, the free carrier screening effect [6] is studied by varying the doping concentration in GaN NW arrays on silicon (111) substrate by molecular beam epitaxy as shown in Figure 1 where undoped and Si-doped GaN NWs are prepared. Piezoelectric measurements were performed by AFM in contact mode using a Pt coated Si tip. As shown in Figure 2, while no output current is detected from the undoped GaN, a 0.07nA output current is harvested from the Si-doped GaN with a force of 3nN because of doping-induced lower resistivity.

We also study the effect of strain on currentvoltage characteristics of NWs by applying normal forces on tops of individual NWs with an AFM tip in Figure 3. With the normal force, the Schottky barrier height (SBH) at the Pt site is decreased but is increased at the Ag site due to the piezotronic effect. Consequently, this effect results in a current

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Free carrier screening effects on piezotronic properties and piezoelectric nanogenerators of GaN nanowire arrays

[5] J. Liu, P. Fei, J.H. Song, X.D. Wang, C.S. Lao, R. Tummala, Z.L. Wang, Nano Letters 8 (2008) 328-332.

[6] Y. Gao, Z.L. Wang, Nano Letters 9 (2009) 11031110.

Figures

Figure 1: Vertically aligned GaN NW array grown on the Si substrate.

Side-view SEM images.

Figure 2: Compare different doping concentration piezoelectric output current shown in the 3D graph.

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Figure 2: (a)Schematics of experimental setup for measuring I-V characteristics of a single GaN NW by an AFM tip under various normal applied forces; (b) plot of ln I as a function of V (for si doped GaN sample) (c) I-V curves of undoped GaN; (d) I-V curves of Si doped GaN ; (e) calculated change in Schottky barrier height from the measured I-V curves in (c) and (d).

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Oral Nickel foam supported MnO2 nanosheet arrays for electrochemical energy storage

Lifeng Liu M. Kundu

lifeng.liu@inl.int

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nature of the MnO2 nanosheets shortens lithium insertion/extraction distances, offering enhanced rate capability; iii) the fact that nearly all nanosheets have a direct intimate contact with the underlying nickel foam (see the SEM image) and the binder free nature of the electrode eliminate the extra contact resistance between the current collector and active materials which usually prevails in an electrode using binder, therefore facilitating the electron transport in the electrode.

Our results manifest that nickel foam supported MnO2 nanosheets hold great promise for use as high-performance anode in lithium-ion batteries.

Figures

Figure 1: (a) Rate capability of nickel foam supported MnO2 nanosheet arrays for use as an electrode in lithium-ion batteries.

Inset: SEM and TEM micrographs. (b) Specific capacitance of the nickel foam supported MnO2 nanosheet electrode as a function of current densities.

Inset: cyclic voltammograms and charge/discharge profiles. Electrolyte: 2 M KOH solution.

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Well-defined ď §-MnO2 nanosheet arrays have been grown on nickel foam current collectors by onestep electrodeposition followed by lowtemperature thermal annealing. Extensive SEM and TEM investigations reveal that the nanosheets are 20 nm thick on average and highly porous (see Fig. a below). The as-fabricated nickel foam supported MnO2 nanosheets are directly utilized as an electrode in lithium-ion coin cells without using any binder. They are found to possess remarkably high specific capacity, which is around 1250 mAh/g at a charge/discharge current density of 100 mA/g.

Even at a current density as high as 1000 mA/g, the specific capacity of these nanosheets still remains 680 mAh/g, much higher than the theoretical capacity of graphite (372 mAh/g) â&#x20AC;&#x201C; the anode material currently being widely used in commercial lithium-ion batteries. Moreover, these nanosheets also exhibit very good cycling performance and a nearly 100% Coulombic efficiency. Aside from lithium-ion coin cells, supercapacitors based on nickel foam supported MnO2 nanosheets are also fabricated and found to be able to work within a wide potential window from 0 to 1V versus saturated calomel electrode (SCE). Extensive electrochemical tests confirm that the MnO2 nanosheet based supercapacitors have reasonably high specific capacitance, good rate capability and satisfactory cycling performance (Fig. b).

The excellent electrochemical performance of the as-fabricated MnO2 nanosheets/nickel foam electrodes can be attributed to the following advantages of the electrode structure: i) the open porous network of MnO2 nanosheets effectively enhances the electrolyte/electrode contact area, and facilitates the mass transport of electrolyte and different charge carriers; ii) the ultrathin

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International Iberian Nanotechnology Laboratory (INL), Av. Mestre Jose Veiga, 4715-330 Braga, Portugal

Oral 1

3D graphene supercapacitor for energy applications

Javier Martinez 1 1 A. Bosca , J. Pedros 1,2 1,3 D. J. Choi , S. Shrestha V. Barranco4, J.M. Rojo4 1 and F. Calle

1

ISOM Instituto de Sistemas Optoelectronicos y Microtecnologia, Universidad Politecnica de Madrid, Av. Complutense s/n. Madrid 28040. Spain 2 Division of Materials Science and Engineering, Hanyang University, Seoul, 133-791, Korea 3 Institute of Engineering, Tribhuvan Univ,Pulchowk, Lalitpur, Nepal.

4 CSIC â&#x20AC;&#x201C; Instituto de ciencia de materiales de Madrid. Cantoblanco, Madrid, Spain

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Due to its excellent mechanical, optical and electrical properties, graphene a 2D sp 2 hybridized carbon sheet with one-atom thickness, has attracted increasing attention in recent years [1]. Its high theoretical surface area (2630 m2 g-1) and high electrical conductivity make it an attractive material for applications in energystorage systems [2]. Considering this facts, the fabrication of a supercapacitor with graphene will provide an energy storage device with high power performance, long life cycle and low maintenance cost [3].

Graphene can be prepared by several techniques: mechanical exfoliation from graphite, precipitation on a silicon carbide surface, reduction of exfoliated graphene oxide, and chemical vapor deposition (CVD) growth on Cu or Ni. One of the most used is CVD, and the synthesized graphene is commonly grown on a flat metal foil or thin film. This method provides high quality graphene, but the amount of energy than can be stored in a monolayer is quite small. In order to solve that problem, it is necessary to use 3D graphene structures.

A commercial Ni foam was used as a catalytic metallic mesh to growth graphene by plasmaenhanced CVD (PECVD). Analyzing the sample by Raman spectroscopy, one can observe that the graphene has a few number of monolayers. In a posterior step, the Ni template was removed immersing the sample in HCl acid during several hours. The graphene foam obtained was characterized by scanning electron microscopy (SEM) showing similar morphology than the original foam. This graphene foam can be used as an electrode in a supercapacitor device.

A home-made supercapacitor cell was built in polypropylene with two stainless steel collectors

javier.martinez@upm.es

(Fig. 1). Two 3D graphene foam discs were inserted inside the cell with a separator in the middle. This sandwich structure was dipped in a 1 mol L-1 KOH aqueous solution that acts as the electrolyte. The two collectors of the supercapacitor cell were connected to a potentiostat/galvanostat equipment. The electrochemical measurements are plotted in Figure 2. In this graph one can observe the charge and discharge of the 3D graphene supercapacitor. The specific capacitance of this device is 2 F g-1, but further capacitance values can be reached by using several additives, like metal oxide nanoparticles or carbon nanotubes.

Acknowledgements: This work has been partially supported by Repsol (Programme Inspire) and Ministerio de EconomĂ­a y Competitividad (Project No. TEC 2010-19511).

References [1] B. Luo, S. Liu, L. Zhi, Small 8 (2012) 630.

[2] M. D. Stoller, S. Park, Y. Zhu, J. An, R. S. Ruoff, Nano Letter, 8 (2008) 3498.

[3] X. Cao, Y. Shi, W. Shi, G. Lu, X. Huang, Q. Yan, Q. Zhang, and H. Zhang, Small 7 (2011) 3163.

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Figure 1: Picture of the graphene supercapacitor cell.

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Figure 2: Charge/discharge cycles in the graphene supercapacitor cell at 0.5 mA and 1 mA.

Oral Transparent and flexible electrodes based on metallic nanowire networks for optoelectronic devices

Céline Mayousse C. Celle A. Carella and J. - P. Simonato

celine.mayousse@cea.fr

CEA-LITEN / DTNM / LCRE, 17 rue des Martyrs, 38054 Grenoble, France

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Transparent conductive thin films are widely used in technologies like solar cells, light-emitting diodes, and display technologies. The fabrication of transparent conductive films is currently realized with thin films of transparent conductive oxides (TCOs), and in particular indium tin oxide (ITO). The asmade ITO transparent conductors suffer from limitations like costly fabrication process and brittleness. The use of solutionprocessable nanomaterials appears as a promising alternative since it affords a large area, low-cost deposition method with high performances. In the past few years, extensive efforts have been performed to develop flexible transparent electrodes based on metallic nanowires and in particular silver nanowires (Ag-NWs) [1]. Among metals, silver has the highest thermal conductivity and the lowest electrical resistivity, thus it is a good candidate for fabrication of transparent conductive electrode.

Thanks to the polyol method, silver nanowires are rather easy to make in large amount from semibatch solution reactions [2]. A simple decantation process has been developed to remove remaining nanoparticles and organics instead of tedious and time-consuming centrifugation steps. The mean length of nanowires is ~10 μm and diameters are in the 50-100 nm range (see figure 1). Very high aspect ratios are necessary to allow fabrication of percolating random networks with very good transparency and electrical conductivity.

Ag-NWs dispersed in methanol have been spincoated or spray-coated on flexible substrates (see figure 1). The sheet resistances of the electrodes are measured by a four probe resistivity meter and the transmittance by a UV-Vis-NIR spectrophotometer. In the standard process, sheet resistance of only few tens of Ohm.sq-1 are

achieved above 90% of transmittance, which is comparable to the ITO performances.

As shown in figure 2, flexible electrodes present good mechanical properties, allowing small radius of curvature and stable sheet resistance after hundreds of flexions.

Thanks to their performances, silver nanowires are good candidates to be integrated into flexible optoelectronic devices [3]. A key point of these devices is the control of energetic level alignment to allow charge injection and collection between electrode and active materials. For that, the work function of silver nanowire networks should be tuned. This modulation can be made by covering the nanowires with a thin layer of metal oxide (ZnO, TiOx, WO3,…), polymer layer or selfassembled monolayers (SAMs). Work function values measured by Kelvin probe force microscopy (KPFM) will be presented.

We will present our work dealing with the solution processed fabrication of random networks of AgNWs, made by printing process. The very low sheet resistance and high transparency of the flexible electrodes, that are comparable to those of ITO, allowed us to integrate them in various functional devices such as thermochromic displays [2], organic solar cells or touch screens [4] (see figure 3).

References [1] D. S. Hecht, L. Hu, and G. Irvin, Advanced materials, 23 (2011) 1482-513.

[2] C. Celle, C. Mayousse, E. Moreau, H. Basti, A. Carella, and J.-P. Simonato, Nano Research, 5 (2012), 427-433.

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[3] J. Lee, P. Lee, H. Lee, D. Lee, S. S. Lee, and S. H. Ko, Nanoscale, 4 (2012). 6408-14.

[4] C. Mayousse, C. Celle, E. Moreau, J-F. Mainguet, A. Carella and J-P Simonato, submitted.

Figures

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Figure 1: Fabrication process of transparent Ag NW Electrodes.

Figure 2: Mechanical properties of flexible silver nanowire based electrodes.

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Figure 3: Silver nanowire based transparent and flexible capacitive sensor a) Change of oscillation value by touching b) LED switching on c) Recognition of each electrode (1,2,3,4).

Invited 1

Functional catalysts for hydrogen production and uptake, and oxygen reduction based on modified carbon nanotubes networks

Serge Palacin 1 2 A. Le Goff , V. Artero 1 1 B. Jousselme , A. Morozan P. T. Dinh2, N. Guillet3 1 2 R. Métayé ; Fihri, A. 2 and M. Fontecave

1

serge.palacin@cea.fr

Chimie des Surfaces et Interfaces, DSM/CEA Saclay; Chimie et Biologie des Métaux, DSV/CEA Grenoble 3 Technologies de l'Hydrogène, LITEN/CEA Grenoble 2

Interconversion of water and hydrogen in unitized regenerative fuel cells is a promising energy storage framework for smoothing out the temporal fluctuations of solar and wind power.

However, replacing currently used platinum catalysts by lower-cost and more abundant materials is a pre-requisite for this technology to become economically viable.

We show that the covalent grafting of bio-inspired catalysts onto multiwalled carbon nanotubes results in highly active material, even under the strongly acidic conditions required in classical PEMFCs. Hydrogen evolves from H2SO4 solution with very low overvoltages (20 millivolts), and the catalyst exhibits exceptional stability (> 100,000 turnovers). One of those catalysts is also very efficient for hydrogen oxidation, exhibiting current densities similar to those observed for hydrogenase-based materials.

Besides, similar carbon nanotubes networks are shown to be highly platinum-free efficient catalysts for oxygen reduction.

[7] Morozan, A.; Jousselme, B.; Palacin, S.; Energy & Environ. Sci. 2011, 4, 1238.

Figures

References

492

[1] Andreiadis, E. S. et al ; Nature Chemistry 2013, 5, 48-53.

[2] Tran, P. D. et al ; Angew. Chem. Int. Ed. 2011, 50, 1371-1374.

[3] Le Goff, A. et al ; Int. J. Hydrogen Energy 2010, 35, 10790-10796.

[4] Le Goff, A. et al ; Science 2009, 326, 13841387.

[5] Morozan, A. et al ; Chem. Commun. 2012, 48, 4627-4629.

[6] Morozan, A. et al ; ChemSusChem 2012, 5, 647 – 651.

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Oral Nanocomposites based on electronically conducting polymers / aligned carbon nanotubes for electrochemical storage in liquid media 1

CEA-IRAMIS-SPAM, Laboratoire Francis Perrin, CNRS URA 2453, Gif-sur-Yvette, Franc Laboratoire de Physico-chimie des Polymères et des Interfaces (LPPI), EA 2528, Université de Cergy-Pontoise, Franc 3 Laboratoire de Physico-chimie des Matériaux et des Biomolécules (PCMB), EA 4244, Université François Rabelais, Tours, France

Mathieu Pinault

1

F. Tatard1,2, M. Porcher 1,2,3 S. Lagoutte2, F. Tran-Van3 F. Ghamouss3, M. MayneL’Hermite1 and P. - H. Aubert2

mathieu.pinault@cea.fr

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current density, galvanostatic profile…). SEM coupled with EDX analyses have been performed along the aligned MWNT carpet cross section after electropolymerization of the ECP in order to investigate the spatial chemical elements distribution and specially the sulfur one that could be linked to the presence of the P3MT at the surface of the MWNT. Figure 2b confirms the homogeneous distribution all along the carpet length from the bottom to the top. TEM images (Figure 2 c) have also been performed in order to confirm the presence of the polymer as a uniform layer covering the external surface of each MWNT and evaluate the morphology and thickness of the polymer layer. Preliminary results concerning the elaboration and the performance of nanostructured ECP/aligned nanotubes will be presented, showing a significant increase of the specific capacitance Cm of the nanocomposite (180 F/g) and the possibility to obtain selfsupported and flexible nanocomposite carpets.

References [1] C. Arbizzani, M. Mastragostino and L. Meneghello, Electrochimica. Acta, 41, 1, 1996, 21.

[2] D. Bélanger, X. Ren, J. Davey, F. Uribe, S. Gottesfeld, J. Electrochem. Soc., 147, 2000, 2923.

[3] J. C. Carlberg, O. Inganäs, J. Electrochem. Soc., 144 , 1997, L61.

[4] A. Laforgue, P. Simon, J. F. Fauvarque, Synth.

Met., 123, 2001, 311.

[5] M. Pinault, V. Pichot, H. Khodja, P. Launois, C. Reynaud and M. Mayne-L’Hermite, Nano Lett 5 (12) 2005, 2394–2398.

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One of the obstacles in transportation (urban or military) is the use of autonomous electrical power sources (rechargeable batteries, fuel cells, etc.).

These devices do not allow for high enough specific powers, needed for the different type of applications they are expected for and limit their dynamical performances. For several years, developments have been achieved and have led to the development of supercapacitors. These components are characterized by much higher specific energies compared to classical capacitors as well as higher specific powers compared to electrochemical batteries Recently, with the development of supercapacitors, electronically conducting polymers (ECPs) have been suggested as promising materials for electrode elaboration due to their capacitance that can theoretically reach 200 to 1000F/g with polythiophene, polyaniline or polypyrroles derivatives.[1-4] Nevertheless, as most of the ECP, their low cyclability is still the limiting factor for a large development and their use for electrode elaboration often lead to an important decrease of electrode capacitance (80100F/g). In order to solve this problem nanostructuration of the ECP and its use with ionic liquids could be considered as a promising way.

In this study, we present the elaboration of nanocomposites made of poly(3-methylthiophene) (P3MT) as ECP electrodeposited onto nanostructured electrode made of aligned multiwalled carbon nanotubes (CNTs) (Fig.1) obtained by aerosol-assisted CCVD [5-6]. We will present the optimization of the electropolymerization parameter leading to controlled thickness of the ECP on the CNT acting as a template electrode and to the homogeneity of the coating in the depth of the carpet (TEM, SEM), depending on several parameters (concentration,

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2

[6] Castro C, Pinault M, Coste-Leconte S, Porterat D, Bendiab N, Reynaud C, Mayne-Lâ&#x20AC;&#x2122;Hermite M, Carbon 48, 2010, 3807-3816.

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Figure 1: SEM (a) and TEM (b) images of aligned MWNT carpets before polymers grafting.

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Figure 2: (a-b) SEM-EDX micrograph showing the homogeneous sulphur atom (in green) localization onto the aligned nanotubes carpet. (b) TEM micrograph of individual CNTs recovered by an electrosynthesized P3MT in ionic liquid media .

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Oral Low energy consumption electrochromic systems based on metallo-organic polymers

1

Miguel Ribeiro 1 2 J. Fonseca , M. Nunes 2 1 M. Araújo , A. Carneiro C. Moura3 and 2 C. Freire

1

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The polymeric films were characterized by cyclic voltammetry, in-situ UV-Vis spectroscopy and Xray photoelectron spectroscopy, in two different states: as-prepared and passivated by continuous redox cycling.

Among the films studied, the poly[Ni(3-Mesalen)] showed the greatest electrochemical stability, exhibited colour change during around 9000 oxidation-reduction electrochemical cycles, with a good optical contrast.

The electrochromic devices were fabricated using an ionic conductive polymeric gel based on PMMA and a lithium salt, with lifecycles around 3000 oxidation-reduction electrochemical cycles.

References [1] A. Branco, C. Pinheiro, J. Fonseca, J. Tedim, A. Carneiro, A.J. Parola, C. Freire, F. Pina, Electrochem. Solid St. 2010, 13, p. J114.

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Electrochromic materials are functional materials whose optical properties can be controlled by electrical stimulus, and therefore has considerable interest for different types of optical devices such as displays, light shutters, smart windows, variable-reflectance mirrors, smart labels and variable-emittance thermal radiators.

The majority of commercial available electrochromics materials are based on metal oxides such as tungsten trioxide or small organic molecules such as viologen and, although having long lifetimes they are usually rigid and their color palette is limited. The most promising alternative materials are probably conductive polymers. Being by nature flexible, they are characterized by high contrast ratios, fast switching times and low energy consumption. Additionally, their color states can be fine tuned by chemical functionalization: however, their major drawbacks for successful commercialization are still short term durability and large scale processability.

The poly[Msalen] are metallo-organic polymers based on salen-type complexes, which the electrochromic behavior have been recently extensively studied with promising results, specially, regarding to electrochemically stability.[1] In this work, electrochromic systems based on poly[Ni(II)salen] were obtained by electropolymerisation of a rational set of Ni(II) salen complexes. The deposition was performed in flexible polyethylene terephthalate coated with indium-tin oxide (ITO/PET), by cyclic voltammetry.

The experimental conditions, namely the supporting electrolyte and the number of potential cycles, were optimized for each complex, in order to fabricate films with good adherence to the substrate, good optical contrast and high cycle-life.

mribeiro@centi.pt

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CeNTI – Centre for Nanotechnology and Smart Materials, 4760-034 Vila Nova de Famalicão, Portugal 2 REQUIMTE /Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, 4169-007 Porto, Portugal 3 CIQ / Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, 4169-007 Porto, Portugal

Invited Recent Research & Development at American Elements Using Nanotechnology in Fuel Cells

Michael N. Silver

michael.silver@americanelements.com

American Elements 10884 Weyburn Avenue Los Angeles, CA, USA

496

Recent research at American Elements has shown how nanoscale materials can improve the performance of both Solid Oxide (SOFC) Fuel Cells and Proton Exchange Membrane (PEM) Fuel Cells; the two fuel cell technologies with the greatest industrial potential.

The greatest barrier to the use of solid oxide fuel cells (SOFC) in automotive and aerospace applications is the high temperature at which they operate (800°+ C). Nanoparticle usage is shown to reduce the operating temperatures of SOFCs, facilitating their possible usage in automobiles and other low temperature applications.

The typical electrolyte in SOFCs is yttria stabilized zirconia (YSZ). Research has shown that using nanoscale YSZ increases ionic conductivity at lower temperatures. Additionally, the typical SOFC anode is composed of a nickel cermet (NiO/YSZ). Using nanoscale NiO and YSZ to produce the cermet increases the area of electron conduction without reduction in gas path flow; further reducing operating temperatures.

Carbon nanotubes have the potential to reduce or eliminate the use of platinum in proton exchange membrane (PEM) fuel cells which has made them cost prohibitive for many uses. Research at American Elements has shown that use of multiwalled carbon nanotubes in replacement of carbon graphite dramatically increases the conductivity of the electrolyte. This may make it possible to replace expensive platinum with less expensive alternatives, such as palladium.

Another interesting area of ongoing PEM investigation involves the use of “controlled growth” platinum nanowires grown on carbon nanospheres. Similar research is underway at American Elements coating graphene with

platinum nanoparticles and coating “Bucky Balls” (C60 Nanoparticles) with platinum nanoparticles.

Current research showing how nanotechnology may solve the most vexing problems holding back full commercialization of fuel cells is discussed.

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Invited Ion confinement in carbon nanopores - application to supercapacitors 1

Université Paul Sabatier - Toulouse III, Toulouse, France UPMC University Paris 06, CNRS, ESPCI UMR 7195 PECSA, 75005 Paris, France 3 Dept. Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA

1

Patrice Simon 1 1 W.-Y. Tsai , R. Lin 1 1 P.-L. Taberna , B. Daffos M. Salanne2, B. Rothemberg2 2 C. Merlet and 3 Y. Gogotsi

2

Figures

Figure 1: Structure of the BMI,PF6 ionic liquid inside electrified pores of microporous carbons; from [1].

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This presentation will focus on different approaches for improving the energy density of electrochemical Capacitors. In a first step, we will show by electrochemical measurements how the control of the porous structure (pore size) of microporous carbons can greatly enhance their gravimetric capacitance. The basic mechanism of this capacitance enhancement will be explained thanks to recent results obtained by atomistic modeling [1], whose results were recently confirmed back by electrochemical experiments.

In a second step, we will present results about the characterization of new electrolytes based on eutectic mixtures of ionic liquids, for widening the operation temperature range and the single cell voltage. High voltage window up to 3.7V at room T were obtained, thus increasing the energy density.

Operation temperature down to -50°C were found to be possible thanks to the unique feature of the IL eutectic mixture that stays liquid at these temperature [2]. Modifying the carbon / electrolyte interface by selecting carbon with highly accessible surface area. Such approach is seems promising for designing electrochemical capacitors with large temperature range and high voltage.

simon@chimie.ups-tlse.fr

Figure 2: Normalized capacitance (C/C20°C) for the different carbon electrodes in (PIP13FSI)0.5(PYR14FSI)0.5 ionic liquid mixture and PC + 1 M TEA-BF4 electrolytes. From [2].

References

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[1] . Merlet, B. Rotenberg, P.A. Madden, P.L.Taberna, P. Simon, Y. Gogotsi, and M. Salanne, Nature Materials 11 (2012) 306-310.

[2] R. Lin, P.-L. Taberna, S. Fantini, V. Presser, C. R. Pérez, F. Malbosc, N. .L. Rupesinghe, K. B.K. Teo,¶ Y. Gogotsi and P. Simon, Journal of Chemistry and Physical Letters 19 (2011) 23962401.

Invited Powerful and efficient energy harvesting with resonant-tunneling quantum dots

Björn Sothmann 2 A. N. Jordan 3 R. Sánchez and M. Büttiker1

1

1

Département de Physique Théorique, Université de Genève, CH-1211 Genève 4, Switzerlan 2 Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA 3 Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Cantoblanco, E-28049 Madrid, Spain

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The main purpose of energy harvesting is to collect energy from the ambient and to convert it into useful work. Of particular interest are thermoelectric energy harvesters. They can be applied, e.g., in computer chips where they convert waste heat back into electricity. One of the central goals of research in this field is to find highly efficient thermoelectrics. Mesoscopic solidstate physics can help to achieve this goal.

Quantum dots - nanometer-sized, artificially made structures – in the Coulomb-blockade regime have been shown to be highly efficient heat- to chargecurrent converters that can even reach Carnot efficiency [1]. Unfortunately, they deliver only very little power since transport occurs via tunneling of single electrons. Chaotic cavities connected to reservoirs via many open transport channels have been shown to yield currents that are two orders of magnitude larger [2]. However, the resulting power is comparable to devices in the Coulombblockade regime and decreases as number of channels is increased.

This suggests that systems with a single open transport channel are the optimal candidates for powerful and efficient thermoelectric setups. A paradigmatic realization of such a single-channel conductor is given by resonant tunneling through a quantum dot.

Here, we consider a setup consisting of a central cavity in thermal equilibrium with a heat source. It is connected to two cold electronic reservoirs via quantum dots with a single resonant level.

Transport through the system can be described via scattering matrix theory. In the limit of small level width, we can solve the system analytically. We find that heat and charge currents are proportional to each other. Furthermore, the device can reach Carnot efficiency, i.e., it acts as an optimal

bjorn.sothmann@unige.ch

converter. In addition, we provide a numerical analysis for arbitrary system parameters.

Optimizing level position and width to maximize the output power, we find that the maximal power is given by P=0.4 (kΔT)2/h. For a temperature difference of ΔT=1 K, the device thus delivers 0.1 fW of power.

In order to scale up the output power, one can put many such heat engines in parallel. A practical way to realize this parallelization is shown below. A large central cavity is sandwiched between two layers of self-assembled quantum dots. Transport between the cavity and two cold, external electrodes is only possible via the quantum dots.

Interestingly, the layered structure can help to reduce phononic leakage heat currents that would otherwise reduce the device efficiency.

Furthermore, we find this proposal to be robust with respect to fluctuations of dot properties.

References [1] R. Sánchez and M. Büttiker, Phys. Rev. B, 83 (2011) 085428.

[2] B. Sothmann, R. Sánchez, A. N. Jordan and M. Büttiker, Phys. Rev. B, 85 (2012) 205301.

[3] A. N. Jordan, B. Sothmann, R. Sánchez and M. Büttiker, Phys. Rev. B, 87 (2013) 075312.

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Figures

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Figure 1: Right: Power P of a quantum-dot energy harvester as a function of the contact conductance G. In the Coulomb-blockade regime, power grows linearly with the conductance. For large conductances, the power decays as 1/G. Left: Sketch of a parallelized heat engine based on self-assembled quantum dots. Top and bottom electrode (blue) are connected via quantum dots (yellow) embedded in an insulating matrix (transparent) to a central hot cavity (red).

Invited Phonon Engineering for Heat Transport Control

Clivia M. Sotomayor Torres 1, 2 E. A. Chavez and 1 F. Alzina

1, 2, 3

1

Catalan Institute of Nanotechnology (ICN), 08193 Bellaterra, Spain.

Dept. of Physics, Universitat Autònoma de Barcelona, 08193 Bellaterra Barcelona, Spain.

3 Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain.

2

500

In the quest for alternative state variables, interest in phonon device concepts has been growing continuously over the last years [1]. Although somewhat far away from practical realisations, phonon engineering is perceived as a possible avenue for future information processing [2]. In fact, phonon engineering for thermal management in nanoelectronics, is considered by the semiconductor research communities in the USA and Asia as paramount for progress in the control of heat dissipation [3] and in the generation of thermoelectricity. Progress has been made in these fields enabled by advances in nanoscale materials, nanofabrication, theory and simulations methods and the increasing ability to measure nanoscale thermal properties, especially thermal conductivity and thermal conductance, which has greatly increased our understanding of phonon transport in the nanoscale while still leaving a huge number of research questions unanswered. The latter are a condition sine qua non for further progress in the physics and applications of phonons.

In this talk we will describe the possibility of engineering the nanoscale thermal properties in nanometer sized plates for a directionality control of the heat transport, as in thermal rectification.

For this purpose, we will show that the classical thermal rectification arising in certain cases from the contact of two dissimilar bulk materials with different temperature dependence of the thermal conductivity can be extended to the Si/Ge system when thickness effects are taken into account.

Moreover, the directionality of the in-plane heat flow in a Si plate can be achieved by tuning the thickness and the impurity concentration along the cross section of the plate. We have designed several potential structures with this function in

Clivia.sotomayor@icn.cat

mind and we will discuss the physics behind them as well as possible practical proposals for their realisation.

References [1] See, e.g., C. Dames, “Solid state thermal rectification with existing bulk materials”, ASME Journal of Heat Transfer 131, 061301-1 (2009).

[2] S. Sklan and J. C. Grossman, in Son et Lumière: from microphotonics to nanophononics, Les Houches, France, September 17th to 28th, 2012. http://arxiv.org/abs/1301.2807.

[3] J Welser, “Priorities of the NRI in Computing Technologies”, presentation at the Guardian Angels Worlshop, March 2012, San Francisco.

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Oral Photochromic electrospun fibers based on tungsten hexachloride

Amin Tabatabaei Mohseni E. O. Zayim

amintabatabaei@itu.edu.tr ozesra@itu.edu.tr Nanoscience & Nanotechnology Program, Istanbul Technical University, Maslak, Istanbul, Turkey

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[1] Heinz D端rr, Henri Bouas-Laurent, Photochromism: Molecules and Systems, ELSEVIER, 2003, ISBN: 0-444-51322-1.

[2] Journal of Nanomaterials, Design Modifications in Electrospinning Setup for Advanced Applications, Volume 2011.

[3] Seeram Ramakrishna et al. World Scientific Publishing Co. Pte. Ltd., An Introduction to Electrospinning and Nanofibers, ISBN 981-256415-2.

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References

Figures

Figure 1: Schematics of electrospinning system.

Figure 2: Electrospun microfibers of WCl6/PVP (a) before and (b) after the UV irradiation

501

Photochromism is defined as the light induced reversible change of color [1]. The synthesis and applications of variety of photochromic materials has developed rapidly during the past decade.

Electrospinning is one of the most widely used processes for the production of nanofibers. This technique of producing nanofibers employs electrostatic forces for stretching the viscoelastic fluid [2].

As depicted in a high DC voltage is applied to a polymer fluid such that charges are induced within the fluid until they reach a critical amount resulting in a fluid jet to erupt from the droplet at the capillary tip of the needle. The electrospinning jet will travel towards the region of lower potential, which in most cases, is a grounded metallic collection target [3]. The dry fibers are accumulated on the surface of the collection screen resulting in a nonwoven random fiber mesh of nano to micron diameter fibers. The process can be adjusted to control the fiber diameter by varying the electric field strength and polymer solution concentration.

We report on photochromic properties of tungsten hexachloride (WCl6) and Polyvinylpyrrolidone (PVP) blend solution prepared by electrospinning technique. WCl6/PVP fibers produced by electrospinning on glass substrate represent color alteration under UV lamp as displayed in. The fiber sustains the blue color unless held into darkness. It demonstrates that the photochromic fiber has a very good memory effect. The reversible coloration process takes about 3 minutes while the bleaching process takes about 3 hours. The coloration cycling of the material is repeatedly reversible and its durability has been tested several times functioning acceptably well.

Oral MnO2-based electrochemical supercapacitors on flexible carbon substrates 1

Institute for Systems based on Optoelectronics and Microtechnology, ISOM-UPM, Madrid, Spain 2 United States Naval Research Laboratory, Washington DC, 20375, USA 3 Instituto de Ciencias de Materiales de Madrid (ICMM), CSIC, Spain

502

There is an increasing need for supercapacitors as they are unique in their ability to deliver high power levels over a time span unattainable by a traditional capacitor. We present a low-cost MnO2based chemistry on large area sheets of carbon aerogel paper. The specific capacitance of manganese oxide is typically lower than the best in class of ruthenium oxide; however, the much lower cost and available supply of manganese makes this material much more attractive [1].

MnO2 nanostructures were deposited in aqueous solutions in a covered Teflon container on a commercially available carbon nanofoam paper substrate with specific capacitance of 47 F/g [2].

Prior to growth, the carbon nanofoam (aerogel) paper was washed in methanol and DI water. The MnO2 structures were formed on large area samples of this flexible substrate by an initial reaction based on 20 mL 0.01 M KMnO4 as the vessel was ramped in temperature to 150 C. Subsequently, the reaction was augmented by a continuous drip over 1 hr of a mixture of 20 mL of 0.01 M KMnO4 and hexamethylenetetramine (HMTA) (0.005 M) at 150 C. Examination of the Xray diffraction pattern shows the film formed as αMnO2. The two experiments of α-MnO2 growth resulted in morphologies resembling nanoflower and nanocube structures. Cyclic voltammetry was performed at 1 mV/s or 5 mV/s rate in the safe 00.8 V range, where the applied potential would not dissociate the oxide into Mn+ cations and O- anions [3].

Specific capacitance of MnO2 (CSP,MnO2) and series resistance (RS) at 1 mA and 5 mA of galvanostatic charging current (ICH) were calculated according to the expression CSP,M = mREF∙CREF/(mREF + mELECTRODE) + mMnO2∙CSP,MnO2/(mREF + mELECTRODE). The mass of the MnO2 sample under test is denoted by mELECTRODE,

1,

Marko J. Tadjer 2 3 M. A. Mastro , J. M. Rojo 1 1 A. Boscá Mojena , F. Calle F. J. Kub2 and 2 C. R. Eddy, Jr.

mtadjer@die.upm.es

the mass and specific capacitance of the carbon aerogel (C-aerogel) are mREF and CREF, respectively, and CREF is the measured total capacitance of the MnO2/C-aerogel composite, from which the specific capacitance of MnO2 (CSP,MnO2) can be extracted. Specific capacitance for sample B at 1 mA charging current was increased from 47 F/g to 64 F/g, a 36% improvement over a bare carbon paper surface. However, at 5 mA the CSP of all samples was comparable to within 4 F/g.

Compared to the control sample, the series resistance of sample B had increased by a factor of about 2.4 at 1 mA and about 4.7 at 5 mA, whereas RS of sample C had remained comparable, albeit slightly lower. This was a consequence of the better surface coverage of sample B with the lowconductivity MnO2 film.

Acknowledgements: M.J.T. acknowledges support from the PICATA program at the Moncloa Campus of International Excellence (CEI), Universidad Politécnica de Madrid, Spain. Research at NRL was supported by the Office of Naval Research (ONR).

References [1] M. A. Mastro, et al., Surface Rev. and Lett., vol. 16, no. 4 (2009) 513-517.

[2] S. Hu, R. Rajamani, and X. Yu, 100, 104103 (2012).

[3] D. Kalpana, K.S. Omkumar, S.S. Kumar, N.G. Renganathan, Electrochim. Acta 52 (2006) 1309-1315.

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Figures

Table: Charging current (ICH), specific capacitance (CSP), and series resistance (RS) measurements.

Figure 1: X-ray diffraction indicates that the coating formed as αMnO2.

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Figure 4: SEM micrograph of nanocube-MnO2 (Sample C).

Figure 2: Galvanostatic measurements comparing charge/discharge cycles. Series resistance was determined from V = V2 – V1.

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Figure 3: SEM micrograph of nanoflower-MnO2 (Sample B).

Oral Marta Urdanpilleta G.L. Schulz E. Mena-Osteritz and P. Bäuerle

Institute of Organic Chemistry II and Advanced Materials, University of Ulm, AlbertEinstein-Allee 11 D-89081 Ulm, Germany 1 Dpto. Física Aplicada I, Universidad del País Vasco (UPV/EHU),Pl. Europa 1, 20018 Donostia, Spain.

marta.urdanpilleta@ehu.es

The application of organic materials for the photovoltaic conversion corresponds to the third generation of solar cells. These systems are gaining ground to the classical silicon-based ones, due to their mechanical flexibility, low weight, low cost and eco-friendly potential.

Among the organic materials, poly- and oligothiophenes are two of the most used and studied systems for optoelectronic applications.

They present high stability in neutral state as well as in excited states. The advantage of the oligomeric (or small molecule) approach is that they are defined, monodispersed molecules able to crystallize: the structure-properties relationship of the photovoltaic devices employing oligothiophenes can be thus univocally established.

The solar cell devices based on small molecules are recently attracting increasing attention because of their advantages above conjugated polymeric systems in terms of easiness of purification, higher homogeneity between batches, and therefore higher reproducibility concerning efficiency of the devices. Power conversion efficiencies (PCE) up to 6.9% have been reported for oligomers based on vacuum-processed [1] and 7.4% for solution-processed single junction devices [2]. For this type of devices, probe microscopy can give insights into the distribution of the donor and acceptor within the blend of the photoactive layer. This is necessary to understand the relationship between structure and cell performance, and for a rational design of the cells.

In this contribution, the surface properties of solar cell devices based on DCV-capped quinquethiophene derivative as a donor part have been studied with Atomic Force Microscopy (AFM). Intriguing results correlating the solar cell

504

1

Relation between surface structure and performance of bulk heterojunction organic solar cells

performance and the surface characteristics will be discussed [3].

References [1] R. Fitzner, E. Mena-Osteritz, A. Mishra, G. Schulz, E. Reinold, M. Weil, C. Körner, H. Ziehlke, C. Elschner, K. Leo, M. Riede, M. Pfeiffer, C. Uhrich and P. Bäuerle, J. Am. Chem.

Soc., 134 (2012) 11064.

[2] J. Zhou, X. Wan, Y. Liu, Y. Zuo, Z. Li, G. He, G. Long, W. Ni, C. Li, X. Su and Y. Chen, J. Amer.

Chem. Soc., 134 (2012) 16345.

[3] G.L. Schulz, M. Urdanpilleta, R. Fitzner, E. Brier, E. Mena-Osteritz, E. Reinold, P. Bäuerle (submitted).

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Oral Silicon-Coated Carbon Nanofiber Mat for Anode of Lithium Ion Battery

1,2

Fei Yao 1 1 B. Li , K. So 1 1 J. Chang , V. Quoc An D. Pribat1, C. S. Cojocaru2 1 1 H. Yue , S. Xie 1,* and Y. H. Lee

1

Institute of Basic Science, Center for Integrated Nanostructure Physics, Department of Energy Science, BK21 Physics Division, Sungkyunkwan University, Suwon 440-746, Republic of Korea 2 LPICM CNRS, Ă&#x2030;cole polytechnique, Palaiseau 91120, France

References [1] N. T. Xuyen, E. J. Ra, H. Z. Geng, K. K. Kim, K. H. An, Y. H. Lee, J. Phys. Chem. B, 111 (2007), 11350.

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TNA 2013

Figures

Figure 1: Schematic of a silicon-coated CNF mat fabrication processes; (a) schematic of electrospinning apparatus, (b) the fabricated nanofiber network, (c) apparatus of electrodeposition of Si, and (d) the deposited Si/CNF mat. The inset shows cross section of coaxial type Si/CNF.

Figure 2: SEM images of Si/CNF mat with (a) 200 and (b) 1500 cycles of Si deposition (after 1000 oC annealing). (c) TEM image of Si-200-a.

The EDS line profile along the dashed line is shown in the bottom panel.

505

Si-coated carbon nanofiber (Si/CNF) mat was fabricated by electrochemical method for the anode of lithium ion battery (LIB). The freestanding CNF mat was first fabricated by electrospinning of polyamic acid followed by stabilization and carbonization, and then the asprepared CNF mat was used for Si electrodeposition through cyclic voltametry (CV), as shown in Figure 1 [1]. Spaghetti or granule-like Si was obtained by varying the deposition conditions, see Figure 2 a and b. This Si/CNF mat was directly used as an anode material, which involves neither binders nor additional metal substrate. The best performance was achieved in spaghetti-like Si due to its highly porous nature which can accomodate the volume expansion and large surface area which benifits efficient charge transfer of ions at the electrode/electrolyte interface. The optimized Si/CNF mat anode after annealing at 1000 oC delivered initially a capacity of 1545 mAh/g and 1388 mAh/g after 50 cycles at 0.1 C rate with an average fading rate of 0.34 % per cycle, improving the capacity of pure CNF mat (280 mAh/g at the 50th cycle), as shown in Figure 3.

Our X-ray photoemission spectroscopy and electrochemical analysis revealed that the formation of Si-C bond through high temperature annealing can enhance the adhesion between silicon and carbon at the interface which benefited the cyclic performance of the anode material ultimately.

leeyoung@skku.edu

506

Figure 3: Charge (filled symbols)/discharge (open symbols) capacity in terms of different numbers of silicon deposition cycles (200, 1500 cycles) after high temperature annealing (1000 oC). Capacity was calculated based on silicon mass only.

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SPM

2013

Index SPM2013 Contributions Invited

Pag

■ Adai Colom (INSERM U1006, Univ. Aix-Marseille, France) "High-speed and high-resolution AFM monitorsmembrane protein interactions"

519

■ Pedro J. de Pablo Gómez (Universidad Autónoma de Madrid, Spain) "Physical virology with Atomic Force Microscopy"

520

■ Martien Den-Hertog (Institut Neel, CNRS, Grenoble, France) "Correlation of polarity and crystal structure with optoelectronic and transport properties of GaN/AlN/GaN nanowire sensors"

521

■ Christoph Gerber (J Swiss Nanoscience Institute / Univ. of Basel, Switzerland) "AFM Technologies in Life sciences"

525

■ Julio Gómez (Universidad Autónoma de Madrid, Spain) "Atmospheric contaminants on graphitic surfaces and drive amplitude modulation"

526

■ Mervyn Miles (Nanoscience & Quantum Information Centre, University of Bristol, UK) "From High-speed AFM to 4π AFM"

534

■ Cesar Moreno (NIMS, Japan) "Disentangling atomic contrast on bimodal atomic force microscopy and simultaneous scanning tunneling microscopy on the TiO2(101) anatase surface"

535

■ Aitor Mugarza (ICN, Spain) "Inducing new molecular properties at the metallic interface"

538

■ José Ignacio Pascual (CIC nanoGUNE, Spain) "Forces and Photons in Molecular Tunneling Junctions"

542

■ Jérôme Polesel (CEA IRAMIS / SPSI, France) "Strategies to investigate biological objects with success using piezoelectric tuning fork Atomic Force Microscopy"

545

■ Vincent Repain (MPQ- UMR 7162, Paris , France) "Coupling adatoms or molecules to magnetic surfaces: a scanning tunneling spectroscopy study"

547

■ Dimitri Roditchev (INSP- UMR 7588, Paris, France) "Nano-Scale Confinement in Superconductors: A Scanning Tunneling Spectroscopy Study"

548

■ Volker Rose (Argonne National Lab., USA) "Synchrotron X-ray Scanning Tunneling Microscopy"

Oral

551

Pag

■ Andreas Bettac (Omicron NanoTechnology, Germany)

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515

509

"New Experiments and Applications Made Possible by a Low Temperature 4-Tip STM with UHV-SEM Navigation "

Oral

Pag

■ Xavier Bouju (CEMES-CNRS, France) "Supramolecular nanostructures formed from PTCDI and Ni on the Au(111) surface: STM experiments and theoretical study"

516

■ Muriel Bouttemy (CNRS, France) "New generation Auger nano-probes: a challenging tool for surface chemical analyses at localized scale"

517

■ Andrea Donarini (Institute of Theoretical Physics, Germany) "Topographical fingerprints of many-body interference blocking in STM junctions on thin insulating films"

522

■ José Miguel García-Martín (IMM-CSIC , Spain) "Novel Magnetic Force Microscopy Operation Employing Torsional Resonance Mode"

523

■ Jérôme Lagoute (CNRS-Université Paris Diderot, France) "Spin split molecular orbital induced by interface with a magnetic surface measured by spin polarized STM"

527

■ Lidia Martínez (ICMM-CSIC, Spain) 529

"Novel SuperSharp AFM tips with enhanced resolution and durability"

■ Michael Marz (Karlsruhe Institute of Technology, Germany) 531

"Ni cluster on HOPG: Growth Mode and Electronic Properties studied by STM"

■ Javier Mendez (ICMM - CSIC, Spain) "STM identification of N-doped nanoarchitectures formed by on-surface (cyclo)dehydrogenation of heteroaromatics"

533

■ María Moro Lagares (Instituto de Nanociencia de Aragón (INA), Spain) 537

"The surge of a Kondo lattice in atomic scale structures"

■ Carmen Munuera (ICMM-CSIC, Spain) 539

"AFM electrical characterization of graphene nanoLEDs"

■ Pietro Parisse (INSTM - Elettra Sincrotrone Trieste Unit, Italy) 541

"Mechanical Properties of DNA Nanografted Monolayer"

■ Carmen Perez Leon (Karlsruhe Institute of Technology (KIT), Germany) "Different contrasts in atomically resolved scanning force microscopy images of Si(111) 7x7"

543

■ Pablo Pou (Universidad Autónoma de Madrid, Spain) "The role of the bias voltage and the atomic thermal movements on the STM/FM-AFM images: how is a Si tetramer observed on the Si(111)-7×7 surface?"

546

■ Celia Rogero (Centro de Física de Materiales, Spain) "Bonding and self-organization of functionalized macrocycles: carboxylic versus pyrrole groups"

549

■ Ane Sarasola (UPV/EHU, Spain) "Adsorption of tetrathifulvalene (TTF) on Cu(100): can π-stacked 1-D aggregates be formed at low temperature?"

553

■ Peng Yang (Université Paris Diderot-Paris7, France) "C60-Cox complex built by atomic/molecular manipulation using low temperature scanning tunneling microscopy and its physical properties studied by tunneling spectroscopy"

555

■ Linda Angela Zotti (Universidad Autónoma de Madrid, Spain)

510

"A Molecular Platinum Cluster Junction: A Single-Molecule Switch "

556

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Index SPM2013 Contributions Alphabetical Order I:Invited / O: Oral

Pag

■ Andreas Bettac (Omicron NanoTechnology, Germany) "New Experiments and Applications Made Possible by a Low Temperature 4-Tip STM with UHV-SEM Navigation "

O

515

O

516

O

517

I

519

I

520

I

521

O

522

O

523

I

525

I

526

O

527

O

529

O

531

O

533

I

534

■ Xavier Bouju (CEMES-CNRS, France) "Supramolecular nanostructures formed from PTCDI and Ni on the Au(111) surface: STM experiments and theoretical study"

■ Muriel Bouttemy (CNRS, France) "New generation Auger nano-probes: a challenging tool for surface chemical analyses at localized scale"

■ Adai Colom (INSERM U1006, Univ. Aix-Marseille, France) "High-speed and high-resolution AFM monitorsmembrane protein interactions"

■ Pedro J. de Pablo Gómez (Universidad Autónoma de Madrid, Spain) "Physical virology with Atomic Force Microscopy"

■ Martien Den-Hertog (Institut Neel, CNRS, Grenoble, France) "Correlation of polarity and crystal structure with optoelectronic and transport properties of GaN/AlN/GaN nanowire sensors"

■ Andrea Donarini (Institute of Theoretical Physics, Germany) "Topographical fingerprints of many-body interference blocking in STM junctions on thin insulating films"

■ José Miguel García-Martín (IMM-CSIC , Spain) "Novel Magnetic Force Microscopy Operation Employing Torsional Resonance Mode"

■ Christoph Gerber (J Swiss Nanoscience Institute / Univ. of Basel, Switzerland) "AFM Technologies in Life sciences"

■ Julio Gómez (Universidad Autónoma de Madrid, Spain) "Atmospheric contaminants on graphitic surfaces and drive amplitude modulation"

■ Jérôme Lagoute (CNRS-Université Paris Diderot, France) "Spin split molecular orbital induced by interface with a magnetic surface measured by spin polarized STM"

■ Lidia Martínez (ICMM-CSIC, Spain) "Novel SuperSharp AFM tips with enhanced resolution and durability"

■ Michael Marz (Karlsruhe Institute of Technology, Germany) "Ni cluster on HOPG: Growth Mode and Electronic Properties studied by STM"

■ Javier Mendez (ICMM - CSIC, Spain) "STM identification of N-doped nanoarchitectures formed by on-surface (cyclo)dehydrogenation of heteroaromatics" "From High-speed AFM to 4π AFM"

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511

■ Mervyn Miles (Nanoscience & Quantum Information Centre, University of Bristol, UK)

I:Invited / O: Oral

Pag

■ Cesar Moreno (NIMS, Japan) "Disentangling atomic contrast on bimodal atomic force microscopy and simultaneous scanning tunneling microscopy on the TiO2(101) anatase surface"

I

535

O

537

I

538

O

539

O

541

I

542

O

543

I

545

O

546

I

547

I

548

O

549

I

551

O

553

O

555

O

556

■ María Moro Lagares (Instituto de Nanociencia de Aragón (INA), Spain) "The surge of a Kondo lattice in atomic scale structures"

■ Aitor Mugarza (ICN, Spain) "Inducing new molecular properties at the metallic interface"

■ Carmen Munuera (ICMM-CSIC, Spain) "AFM electrical characterization of graphene nanoLEDs"

■ Pietro Parisse (INSTM - Elettra Sincrotrone Trieste Unit, Italy) "Mechanical Properties of DNA Nanografted Monolayer"

■ José Ignacio Pascual (CIC nanoGUNE, Spain) "Forces and Photons in Molecular Tunneling Junctions"

■ Carmen Perez Leon (Karlsruhe Institute of Technology (KIT), Germany) "Different contrasts in atomically resolved scanning force microscopy images of Si(111) 7x7"

■ Jérôme Polesel (CEA IRAMIS / SPSI, France) "Strategies to investigate biological objects with success using piezoelectric tuning fork Atomic Force Microscopy"

■ Pablo Pou (Universidad Autónoma de Madrid, Spain) "The role of the bias voltage and the atomic thermal movements on the STM/FM-AFM images: how is a Si tetramer observed on the Si(111)-7×7 surface?"

■ Vincent Repain (MPQ- UMR 7162, Paris , France) "Coupling adatoms or molecules to magnetic surfaces: a scanning tunneling spectroscopy study"

■ Dimitri Roditchev (INSP- UMR 7588, Paris, France) "Nano-Scale Confinement in Superconductors: A Scanning Tunneling Spectroscopy Study"

■ Celia Rogero (Centro de Física de Materiales, Spain) "Bonding and self-organization of functionalized macrocycles: carboxylic versus pyrrole groups"

■ Volker Rose (Argonne National Lab., USA) "Synchrotron X-ray Scanning Tunneling Microscopy"

■ Ane Sarasola (UPV/EHU, Spain) "Adsorption of tetrathifulvalene (TTF) on Cu(100): can π-stacked 1-D aggregates be formed at low temperature?"

■ Peng Yang (Université Paris Diderot-Paris7, France) "C60-Cox complex built by atomic/molecular manipulation using low temperature scanning tunneling microscopy and its physical properties studied by tunneling spectroscopy"

■ Linda Angela Zotti (Universidad Autónoma de Madrid, Spain)

512

"A Molecular Platinum Cluster Junction: A Single-Molecule Switch "

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A b s t r a ct s Alphabetical order

SPM 2013

New Experiments and Applications Made Possible by a Low Temperature 4-Tip STM with UHV-SEM Navigation

a.bettac@omicron.oxinst.com

Omicron NanoTechnology GmbH, 65232 Taunusstein, Germany

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Figures

Figure 1: (a) SEM image of 4 STM probes placed on a Fe-nanowire for 4-point conductance measurements at T < 5 K; (b) High resolution STM image of a Ag(111) surface at T<5K. Imaging parameters: Scan area: 5.7nm x 5.7nm, Ugap= 25mV, Isetpoint=2nA; (c) Atom manipulation of Ag-particles on a Ag(111) surface at 5K. Imaging parameters: Scan area: 48.3nm x 48.3nm, Ugap= 90mV, Isetpoint=5.4nA; (d) High resolution NC-AFM image of a NaCl(001) surface at T=4.4K. Imaging parameters: Δf= - 1.3 Hz, fres= 23.8 kHz, A≈ 0.5 nm, Q≈ 20.000, Ugap= -200 mV.

515

A major challenge in the development of novel devices in nano- and molecular electronics is their interconnection with larger scale electrical circuits required to control and characterize their functional properties. Local electrical probing by multiple probes with STM precision can significantly improve efficiency in analyzing individual nano-electronic devices without the need of a full electrical integration. Recently we developed a new microscope stage that merges the requirements of a SEM navigated 4-probe STM and at the same time satisfy the needs for high performance SPM at low temperatures.

Besides SEM/STM probe fine navigation and NCAFM (QPlus) imaging with atomic resolution at temperatures of T<5K, the excellent STM/AFM performance level of the LT NANOPROBE expands applications to tunneling spectroscopy and even the creation or modification of nano-structures or single atoms by a sharp and precise SPM probe. In this contribution we will focus on measurements that prove the performance level of the instrument as well as on tunneling spectroscopy and atom manipulation experiments on Ag(111) at temperatures of T < 5K.

Andreas Bettac B. Guenther J. Chrost J. Koeble M. Maier and A. Feltz

SPM 2013

Oral

Oral Xavier Bouju 2 2 M. Yu , W. Xu 2 1,3 N. Kalashnyk , Y. Benjalal S. Nagarayan1, F. Masini2 2 1,3 E. Lægsgaard , M. Hliwa 1 1 A. Gourdon , C. Joachim 2 F. Besenbacher and 2 T. R. Linderoth

1

xavier.bouju@cemes.fr

CEMES-CNRS, 29 rue J. Marvig, F-31000 Toulouse, France iNANO and Dep. Phys. & Astronom., Aarhus Univ., DK-8000 Aarhus, Danemark 3 Faculté des sciences Ben M’Sik, Univ. Hassan II-Mohammédia, Casablanca, Morocco 2

Since the invention of local probes based methods, like scanning tunneling microscope (STM) and atomic force microscope (AFM), an important theoretical effort of image interpretation has been performed. Actually, due to many physical effects inherent in these techniques, calculations are necessary to explain the experimental results. In this context, different theoretical models were proposed giving rise to different numerical codes, each of them having specific functionalities or at least having a particular range of validity. In particular the combination of adsorption structure determination coupled to calculated STM images is an efficient methodology to compare with experimental results.

Here, we will focus on supramolecular selfassembly of the organic semiconductor perylene3,4,9,10-tetracarboxylic diimide (PTCDI) together with Ni atoms on the inert Au(111) surface. It is possible by tuning the co-adsorption conditions to synthesize three distinct self-assembled Ni–PTCDI nanostructures from zero-dimensional (0-D) nanodots over one-dimensional (1-D) chains to a two-dimensional (2-D) porous network. The subtle interplay among non-covalent interactions responsible for the formation of the observed structures has been revealed from force-field structural modeling and calculations of partial charges, bond orders and binding energies in the structures [1]. We have found that the role of the Ni atoms in forming the observed structures is not to participate in metal–organic coordination bonding. Rather, the Ni adatoms acquire a negative partial charge through interaction with the substrate and the Ni–PTCDI interaction is entirely electrostatic Calculated STM images have been obtained by using the ESQC code, which is based on an

516

1

Supramolecular nanostructures formed from PTCDI and Ni on the Au(111) surface: STM experiments and theoretical study

extended Hückel approach and allows the determination of the tunnel current inside the STM junction for a broad variety of physical systems [24].

References [1] [2] [3] [4]

M. Yu et al., Nano Res. 5 (2012) 903.

M. Yu et al., ACS Nano 4 (2010) 4097.

M. Yu et al., Chem. Commun. 46 (2010) 5545.

M. Yu et al., Nano Res. 2 (2009) 254.

Figures

Figure 1: Adsorption of PTCDI molecules with nickel atoms on Au(111) giving rise to different structures (left). Calculated structure and STM image of a trimer (right). [1].

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New generation Auger nano-probes: a challenging tool for surface chemical analyses at localized scale

1

Muriel Bouttemy 1,2 2 P.K. Yadav , E. Martinez 1 2 D. Aureau , O. Renault J.M. Hartmann2, E. Delbos3 3 H. El Belghiti 1 A. Etcheberry and 2 A. Chabli

SPM 2013

Oral

1

Institut Lavoisier de Versailles, UMR CNRS-UVSQ 8180, 45 av. des Etats-Unis, 78035 Versailles Cedex, France 2 CEA, LETI, MINATEC Campus, 17 rue des Martyrs – F-38054 GRENOBLE Cedex 9 3 OMG Ultra Pure Chemicals, Les Vieilles Hayes, F-50620 Saint-Fromond

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nuclei (figure 2). The accuracy of Auger quantification is tested on a SiGe multilayer sample1 with Ge concentration varying within the cross section from 6 to 30% (X-Ray diffraction calibration) by 300-500 nm steps.

References [1] K. Tsutsumi, JEOL news 41(1) (2006) 46.

[2] S. R. Raman, D. F. Paul, J. S. Hammond and K. D. Bomben, Microscopy Today 19(2) (2011) 12.

[3] P. K. Yadav, E. Martinez, F. Bertin, M. Bouttemy, E. De Vito, O. Renault, J. M. Hartmann, A. Etcheberry and A. Chabli, IOP Conf. Series: Materials Science and Engineering 41 (2012) 012020.

Figures

Figure 1: Al-LVV et Ga-LMM Auger line profiles and SEM image of the corresponding analysis area on a certified BAM-L200 reference sample (30 kV, 10 nA). The Al0.7Ga0.3As/GaAs stack is presented on top.

517

In recent years, Auger spectroscopy has been neglected on benefit of X-Ray photoelectron spectroscopy giving an easier access to the surface composition and chemical shift. Indeed, thanks to new generation electron sources, developed for high resolution microscopy, ultimate probe size of 10 nm is achieved with the new generation Auger nano-probes. Such equipments are therefore promising tools to address the need of localized chemical characterization of cutting edge structures whose dimensions are reaching the nanometric scale on which “classical” XPS (X-Ray source), with spot size of 400 to 30 microns, only permits to obtain global information. In addition, with energy resolution of 0.1 % (at 2000 eV), nanoAuger electron spectroscopy is not only able to give information about the composition but also, when the chemical shift is high enough, on the chemical environment.

The present work is dedicated to the determination of ultimate performances of nanoAuger spectroscopy. The lateral resolution is evaluated on a certified reference sample, BAML200 (« Bundesanstalt für Materialforschung und prüfung »), constituted of a stack of alternated lines of Al0.7Ga0.3As/GaAs with variable intervals ranging from 700 to 7 nm. Results obtained with the different acquisition modes (point, line profile or mapping) will be presented (figure 1).

Complementary AFM and XPS measurements will permit to extend the discussion about the impact of topography or surface oxidation state on the spatial resolution and on the detection limit. The capabilities of nano-Auger on practical cases are also presented. The question of the origin of the Auger signal with the topography of the sample and the geometry of electrons collection is approached on a textured Si wafer presenting Ni

muriel.bouttemy@uvsq.fr

518

Figure 2: (a) Secondary electron image of a textured Si substrate after Ni nuclei deposition (b) Auger spectra acquired at the positions mentioned on (a) with a spot size of 20 nm (10 kV, 10 nA, dE/E = 0,5% at 2000 eV).

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High-speed and high-resolution AFM monitors membrane protein interactions

Adai Colom I. Casuso and S. Scheuring

SPM 2013

Invited

adai.colom@inserm simon.scheuring@inserm.fr U1006 INSERM, UniversitĂŠ Aix-Marseille, Campus Luminy, 13009 Marseille, France

Membrane-mediated protein-protein and proteinlipid interactions, membrane protein localization, and related dynamics, modulate membrane protein function [1]. So far membrane structure and dynamics could not be studied altogether lacking the technique that analyzes unlabelled proteins at submolecular lateral and high temporal resolution. Here we used high-speed atomic force microscopy (HS-AFM, [2]) to characterize the movements and interactions of unlabelled porin OmpF (Fig. 1, [3]) and aquaporins (Fig. 2, [4]) in native membranes. First an introduction to AFM and its use in membrane biology will be given, followed by an introduction to the membrane proteins and the membrane structure as a current challenge in biology. Using HS-AFM, we are able to describe essential novel aspects that govern membrane protein assembly and membrane superstructure. Protein motion scales roughly with membrane crowding. However molecules display individuality of diffusion behavior ranging from fast moving to immobile molecules trapped by favorable protein-protein associations. We describe the molecular interaction and assembly rationales that we compare with coarse-grained molecular dynamics and Monte Carlo simulations.

Furthermore, the development of a hybrid microscope combining high-speed atomic force microscopy and optical microscopy for the analysis of cells will be discussed. HS-AFM may open a novel research avenue that bridges structure of individual membrane proteins and supramolecular membrane architecture.

[2] T. Ando, et al., Proceedings of the National Academy of Sciences, 2001, 98, 12468.

[3] I. Casuso, et al., Nature Nanotechnology, 2012, 7 (8): 525-529.

[4] A. Colom, et al., Journal of Molecular Biology, 2012, 423 (2): 249-256.

Figures

Figure 1: HS-AFM movie frames (frame rate 477 ms) showing the motion of OmpF trimmers.

Figure 2: HS-AFM movie frames (frame rate 250 ms) showing native AQP0 array assembly (A-E) and disassembly (E-H).

References

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519

[1] D.M. Engelman, Nature, 2005, 438, 578.

Invited Physical virology with Atomic Force Microscopy

Pedro J. de Pablo Gómez

Universidad Autónoma de Madrid, 28049 Madrid, Spain.

Viruses are striking examples of macromolecular assembly of proteins, nucleic acids, and sometimes lipid envelopes that form symmetric objects with sizes ranging from 10s to 100s of nanometers. The basic common architecture of a virus consists of the capsid a protein shell made up of repeating protein subunits, which packs within it the viral genome which can be single or double stranded DNA or RNA depending on the type of the virus.

Virtually every aspect of the virus cycle from DNA packing to maturation to interaction with the host modifies and, in turn, is influenced by the material properties of the virus. In this talk I will show how Atomic Force Microscopy has emerged as a unique technique to unveil some physical properties of viruses, such as stiffness and elasticity, which can be directly related to their structure and function (1). In addition, AFM enables monitoring the dynamics of virus disassembly in real time to unveil the ultimate physical changes to trigger virus infectivity (2).

References

520

[1] Hernando-Pérez, M., Miranda, R., Aznar, M., Carrascosa, J. L., Schaap, I. A. T., Reguera, D., and de Pablo, P. J. Small 8, 2365 (2012).

[2] Ortega-Esteban, A., Pérez-Berná, A. J., Menéndez-Conejero, R., Flint, S. J., San Martín, C., and de Pablo, P. J. Scientific Reports 3, 1434 (2013).

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Correlation of polarity and crystal structure with optoelectronic and transport properties of GaN/AlN/GaN nanowire sensors

2

Martien Den-Hertog F. Gonzalez-Posada R. Songmuang 2 J.L. Rouviere and 2 E. Monroy 2 1

martien.den-hertog@grenoble.cnrs.fr INSTITUT NEEL-CNRS, 25 rue des Martyrs, 38042 Grenoble cedex 9, France CEA-GRENOBLE, INAC / SP2M, 17 rue des Martyrs, 38054 Grenoble cedex 9, France

Semiconductor nanowires (NWs) are promising candidates for many device applications ranging from electronics and optoelectronics to energy conversion and spintronics. Their large surface-tovolume ratio can be used advantageously in sensor applications where especially the chemical inertness and robustness of GaN are highly desirable characteristics, enabling device operation in extreme environments such as high temperature, radiation and extreme pH levels.

In this work, we correlate the crystal structure and heterostructure measured by scanning transmission electron microscopy (STEM) and the photodetector performance of defect-free GaNAlN NW heterostructures on the level of a single NW, paying particular attention to the impact of the measuring environment on the electronic transport and photocurrent dynamics. The effects of GaN/AlN heterostructure engineering and surface states are discussed.

GaN NWs are grown by plasma-assisted MBE on Si(111) [1]. They have a length of 1.2–1.5 μm and a diameter of 30−80 nm. Individual NWs were dispersed on electron transparent Si3N4 membranes and contacted using e-beam lithography.

Using aberration-corrected annular bright field (ABF) and high angle annular dark field (HAADF) STEM, we identify the NW growth axis to be the Npolar [000−1] direction (Fig. 1). The electrical transport characteristics of the NWs are explained by the polarization-induced asymmetric potential profile and by the presence of an AlN/GaN shell around the GaN base of the wire. The AlN insertion blocks the electron flow through the GaN core, confining the current to the radial GaN outer shell, close to the NW sidewalls, which increases the sensitivity of the photocurrent to the environment

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and in particular to the presence of oxygen. The desorption of oxygen adatoms in vacuum leads to a reduction of the nonradiative surface trap density, increasing both dark current and photocurrent [2].

Acknowledgments: Financial support from the French FMN-SMINGUE 2011, the French CNRS and CEA METSA network, the ANR-2011-NANO-027 “UVLamp” project, the EU ERC-StG “TERAGAN” (#278428) project, and the ANR-2013-JCJC "COSMOS" is acknowledged.

References [1] R. Songmuang, T. Ben, B. Daudin, D. Gonzalez, and E. Monroy, Nanotechnol. 21, 295605 (2010).

[2] M. I. den Hertog, F. González-Posada, R. Songmuang, J.-L. Rouviere, T. Fournier, B. Fernandez, and E. Monroy, Nano Lett. 12, 5691 (2012).

Figures

Figure 1: From left to right: schematic of the NW structure, HAADF STEM image of a contacted GaN NW with an AlN insertion. Zoom of the boxed region viewed along the [11-20] direction. Atomic structure of GaN viewed along [11-20] overlaid on an ABF STEM image. I−V characteristic from the same NW device measured in the air and in vacuum, in the dark and under UV illumination.

521

1

1

SPM 2013

Invited

Oral Topographical fingerprints of manybody interference blocking in STM junctions on thin insulating films

Andrea Donarini B. Siegert S. Sobczyk and M. Grifoni

andrea.donarini@physik.uni-r.de Institute of theoretical physics, University of Regensburg, D-93040 Regensburg, Germany

Negative differential conductance is a nonlinear transport phenomenon ubiquitous in molecular nanojunctions [1]. Its physical origin can be the most diverse. In rotationally symmetric molecules with orbitally degenerate many-body states it can be ascribed to interference effects [2,3,4]. We establish in this paper [5] a criterion to identify the interference blocking scenario by correlating the spectral and the topographical information achievable in a scanning tunneling microscopy (STM) single-molecule measurement. Simulations of current-voltage characteristics as well as constant-height and constant-current STM images (see figures below) for a Cu-phthalocyanine on a thin insulating film are presented as experimentally relevant examples.

Figures

Figure 1: Left: Current through a CuPc singlemolecule junction as a function of the substrate (and tip) work function φ 0 and of the sample bias Vb Right: Current obtained from a cut of the left-hand plot corresponding to φ0 = 4.1 eV. The current scale is the same for the left and right panels. The numbers in the current-voltage plot refer to the current maps in Fig. 2 and Fig. 3.

References [1] B. W. Heinrich, M. V. Rastei, D.-J. Choi, T. Frederiksen, and L. Limot, Phys. Rev. Lett. 107, 246801, (2011), and references therein.

[2] S. Sobczyk, A. Donarini, and M. Grifoni Phys.

Rev. B, 85, 205408 (2012).

[3] A. Donarini, G. Begemann, and M. Grifoni Physical Review B, 82, 125451 (2010).

[4] A. Donarini, G. Begemann, and M. Grifoni Nano Letters, 9, 2897 (2009).

[5] A. Donarini, B. Siegert, S. Sobczyk, and M. Grifoni, Physical Review B, 86, 155451 (2012).

Figure 2: Constant-height current maps calculated for different bias voltages. The color bar on the left (right)-hand side corresponds to maps 1 and 3 (maps 2 and 4). The current map in the interference blockade regime (map 4) appears to be flat in the molecule region.

522

Figure 2: Isosurfaces of constant current calculated in the proximity of the Coulomb blockade (upper panel; Vb = 0.5303 V) and nterference blockade (lower panel; Vb = −0.9118 V) regimes. The surfaces correspond, in both cases, to the currents: I = 3.15, 3.075, 3.0, 2.925, and 2.85 pA.

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Novel Magnetic Force Microscopy Operation Employing Torsional Resonance Mode

José Miguel García-Martín A. Kaidatzis

SPM 2013

Oral

jmiguel@imm.cnm.csic.es IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC), Isaac Newton 8, PTM, E-28760 Tres Cantos, Madrid, Spain

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pass method is used for performing MFM measurements: a TM-AFM main scan yields the surface topography, while the long-range magnetic forces are detected using a lifted TR-MFM scan (or a TM-MFM scan, for comparison).

TR-MFM provides two main advantages over conventional TM-MFM measurements. The first is related to the insensitivity of TR mode to out-ofplane forces and most notably, the Van der Waals forces. Thus, the only long-range forces contributing to the signal detection scheme are magnetic forces, allowing the magnetic imaging of a surface with total absence of topography-related signal (see figure 1). The second advantage originates from the minimal flexural oscillation amplitude. As the flexural cantilever oscillation is only excited thermally, the corresponding oscillation amplitude is around 1 nm, more than one order of magnitude lower than in the case of TM-MFM. This provides the ability of performing dynamic MFM measurements with significantly reduced tip sample distance (the tip can even be lowered during the “lifted” scan). As a result, improved spatial resolution can be achieved (see figure 2), while preserving a high signal-to-noise ratio.

Taking into account the above-mentioned advantages, it is argued that TR-MFM provides a significant improvement to a prolific magnetic imaging method widely used in Academia and in Industry.

Acknowledgments: A. K. received funding from the EC through a FP7 Intra-European Marie Curie Fellowship (Grant No. PIEF-GA-2010-272470).

Funding from the Spanish MINECO (refs.

MAT2011-29194-C02-01, MAT2010-10213-E and

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The constant miniaturization of magnetic bits in hard-disk drives creates the need for a convenient and versatile high resolution magnetic imaging method. Magnetic Force Microscopy (MFM), a scanning probe technique, has been widely used for this purpose for more than two decades [1,2].

However, the current MFM lateral resolution in ambient conditions is roughly equal to the magnetic bit size of commercial hard-disks (≈40 nm), making imperative the improvement of MFM performance. In this work, we present the advantages of performing MFM imaging employing the Torsional Resonance (TR) mode of cantilever oscillation [3].

Traditional vibrating tip modes of MFM operation, e.g. Tapping Mode MFM (TM-MFM), employ the flexural ("diving board") cantilever deflection signal for feedback control, while the detection scheme is principally sensitive to forces perpendicular to the sample. However, TR-MFM takes advantage of the torsional (twisting) cantilever deflection. In this case, lateral forces that act on the tip can cause a change in the torsional resonance frequency of the cantilever, allowing the local characterization of sample properties and the detection of in-plane components of force-fields.

The utilization of TR mode for imaging in-plane components of magnetic fields has been demonstrated [4,5], but not extensively studied. In this work, TR-MFM is examined in detail [6].

Measurements have been performed using a commercial scanning probe microscope (Dimension Icon, Bruker). Home-coated magnetic probes have been used: hard magnetic CoCr layers have been deposited on commercial Atomic Force Microscopy (AFM) probes (Nanosensors), using ultrahigh vacuum magnetron sputtering. A double-

CSD2008-00023) and Comunidad de Madrid (S2009/MAT-1726) is also acknowledged.

same position. (a) TM-MFM phase image, lift height: 15 nm, color scale: 0 – 2.4 deg., S/N ratio: 17. (b) TR-MFM phase image, same area as in (a), lift height: -29 nm, color scale: 0 – 1.0 deg., S/N ratio: 4. (c) Line profiles averaged along the indicated directions in (a) and (b). The TM-MFM line profile has been inverted.

References [1] D. W. Abraham, C. C. Williams, and H. K. Wickramasikghe, Appl. Phys. Lett., 53, (1988) 1446.

[2] H. J. Mamin, D. Rugar, J. E. Stern, B. D. Terris, and S. E. Lambert, Appl. Phys. Lett., 53, (1988) 1563.

[3] L. Huang and C. Su, Ultramicroscopy, 100 (2004) 277.

[4] T. Kasai, B. Bhushan, L. Huang, and C. Su, Nanotechnology 15 (2004) 731.

[5] T. Mühl, J. Körner, S. Philippi, C. F. Reiche, A. Leonhardt, and B. Büchner, Appl. Phys. Lett., 101, (2012) 112401.

[6] A. Kaidatzis and J. M. García-Martín, accepted for publication in Nanotechnology.

Figures

Figure 1: MFM phase imaging of a 0.1 Gb/inch2 longitudinal magnetization hard-disk. The images have been obtained at the same position. (a-c) TM-MFM, lift height: 20 nm, (a) topography (0 – 68.4 nm), (b) phase image (0 – 4.3 deg.), signal/noise ratio: 13, (c) derivative of phase image (0 – 10.6 deg/μm). (d-f) TR-MFM, same area as in (a-c), lift height: -5 nm, (a) topography (0 – 60.0 nm), (b) phase image (0 – 0.5 deg.), signal/noise ratio: 25 (c) derivative of phase image (0 – 2.4 deg/μm). As TR mode is sensitive to lateral force gradients, the TR-MFM contrast is reversed with respect to TM-MFM.

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Figure 2: MFM phase imaging of a 100 Gb/inch2 perpendicular magnetization hard-disk. The images have been obtained at the

ImagineNano2013

AFM Technologies in Life sciences

Christoph Gerber

SPM 2013

Invited

Swiss Nanoscience Institute NCCR National Center of Competence for Nanoscience Institute of Physics Univ. of Basel Klingelbergstrasse 82 4056 Basel Switzerland http://cantileversensors.unibas.ch/ChGerber

ImagineNano2013

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Atomic Force Microscopy technologies have come of age and are ubiquitous in many applications in life sciences. Besides allowing high resolution 3 D images of samples close to their native state various technological developments has turned the technique into a multifunctional nanoscopic toolbox in life sciences. A variety of applications will be discussed: High speed AFM: Seeing Molecular Motors at work AFM has entered the clinic:  AFM Force spectroscopy in physiological environment revealing a nanomechanical signature of breast cancer  Taking AFM Technology beyond imaging towards Personalised Healthcare (PHC) diagnostics  Non invasive Breath analyses of patients in cancer diagnosis

Invited Atmospheric contaminants on graphitic surfaces and drive amplitude modulation

Julio GĂłmez-Herrero

Universidad Autonoma de Madrid Departamento FĂ­sica de la Materia Condensada, C03-609 Madrid 28049, Spain

526

Kelvin probe force microscopy images show that the surface potential of graphite changes with time as the contamination covers its surface. Using mass spectrometry we identify the molecular mass of the contaminants to be compatible with that of tetracene, a polycyclic aromatic hydrocarbon (PAH), and its isomers. A combination of desorption and Kelvin probe force microscopy experiments using drive amplitude modulation plus theoretical calculations confirms that these molecules are the main contaminant for graphitic surfaces in air ambient conditions. Interestingly, when the sample temperature is increased above ď ž50 oC the molecules are desorbed and the surface potential becomes fairly homogeneous, suggesting that graphitic surfaces should be almost atomically clean above this temperature. PAHs are potent atmospheric pollutants, potentially carcinogenic, that consist of fused aromatic rings. Incomplete combustion of organic materials can increase the concentration of PAHs in the atmosphere, which in urban regions is enough to totally cover the surface of graphite in a time period that varies from minutes to a few hours. One of the consequences of the adsorption of molecules on graphene is the doping of its surface and the variation of the charge neutrality point originated by the charge transfer between graphene and the contamination layer.

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Spin split molecular orbital induced by interface with a magnetic surface measured by spin polarized STM 1

MPQ, UniversitéParis iderot, Paris 7, CNRS, UMR 7162, Paris 13, France DSM/IRAMIS/SPCSI, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France

1

Jérôme Lagoute 1 L. Kawahara 1 V. Repain C. Chacon1 1 Y. Girard and 1 S. Rousset 2 A. Smogunov and 2 C. Barreteau

SPM 2013

Oral

2

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spectroscopic study of the spin resolved electronic density of states of the adsorbed molecules allowing us to obtain information on the spin dependent transport in the tunnel regime through single C60 molecules. We found TMR values up to 100% that reverses its sign between -0.5V and 0V. A spatial mapping of the spin resolved local density of states allowed to visualize the spin polarization of the molecular orbitals that appear at these energies. Using ab initio calculations all the molecular orbitals observed by STM were identified. The hybridization with the substrate was shown to lead to a spin split of the LUMO state with a large energy separation of 0.5 eV for the spin up and spin down channels. This hybridized molecular state is responsible for an inversion of sign of the tunneling magnetoresistance depending on energy.

These results show the strong spin polarization of a non magnetic molecule contacting a magnetic electrode opening new routes for the engineering of molecular spintronic devices.

References [1] S. L. Kawahara, J. Lagoute, V. Repain, C. Chacon, Y. Girard, S. Rousset, A. Smogunov, and C. Barreteau Nano Lett. 12 (2012) 4558.

[2] R. Wiesendanger, H.-J. Güntherodt, G. G¨untherodt, R. Gambino, and R. Ruf Phys.

Rev. Lett. 65, (2012) 247.

[3] J. Lagoute, S. L. Kawahara, C. Chacon, V. Repain, Y. Girard, and S. Rousset, J. Phys.

Cond. Matt. 23 (2011) 045007.

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Molecular spintronics is based on the exploitation of spin transport properties of organic materials connected to magnetic electrodes. In such devices, the interface between molecules and magnetic electrodes plays a major role. Therefore, the interfacial hybridization and spin polarization between the organic layer and the ferromagnetic electrodes has to be understood at the molecular scale. When an organic molecule is brought into contact with a metallic electrode, its molecular levels are generally broadened and shifted depending on the geometrical and electronic details of the contact. In the case of a magnetic electrode, these broadening and shifting are in principle spin dependent leading finally to a spinpolarized density of states of the molecule itself.

Using spin polarized scanning tunneling microscopy (SP-STM) we have studied the spin polarization of single C60 molecules adsorbed on a Cr(001) substrate [1]. The Cr(001) surface exhibits an antiferromagnetic coupling between adjacent terraces that can be revealed in the dI/dV spectroscopic signal using a tungsten tip coated by an iron layer [2,3]. Comparing the dI/dV spectra of molecules adsorbed on adjacent terraces allows therefore to access to the spin dependant electronic transport of C60 when the tip and the sample are in the parallel or antiparallel magnetic configurations. Figure 1 shows a composite SPSTM image where the 3D topography is color coded by the spin resolved differential conductance levels, revealing the two in-plane opposite magnetization of adjacent chromium terraces. A sparse distribution of single molecules all adsorbed on pentagonal rings allows simultaneous individual and statistical investigation of the spin-dependent transport through the fullerene molecules. We performed a

jerome.lagoute@univ-paris-diderot.fr

Figures

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Figure 1: Constant current STM image (100Ă&#x2014;65 nm2) of the C60 /Cr(001) system mapped with the color coded dI/dU values.

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Novel SuperSharp AFM tips with enhanced resolution and durability

Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas (ICMMCSIC), C/ Sor Juana Inés de la Cruz, 3 28049 Madrid, Spain

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lidia.martinez@icmm.csic.es

than the SuperSharp and the standard probes which makes it particularly interesting for several applications.

The presented tips modification method represents an alternative for the generation of high-aspect ratio tips for high-resolution measurements. It should be mentioned that the modification of the tips by deposition of nanoclusters is a "one step process" that does not need any additional chemical of physical processes. Furthermore, the ability to tune the chemical composition of the deposited nanoparticles implies that the technique can be extended for specific measurements in other force microscopy techniques such as Kelvin Probe Microscopy [3] or magnetic force microscopy.

These tips are commercially available in a recently created spin-off of the CSIC, named Next-Tip [4].

References [1] Spanish patent number P201030059, PCT/ES2011/070319, Elisa L. Román García, Lidia Martínez Orellana, Mercedes Díaz Lagos, Yves Huttel.

[2] L. Martínez, M. Tello, M. Díaz, E. Román, R. Garcia, and Y. Huttel, Review of Scientific Instruments, 82 (2011) 023710.

[3] C. V. Manzano, O. Caballero-Calero, S. Hormeño, M. Penedo, M. Luna, M. S. MartínGonzález, J. Phys. Chem. C, 117 (2013) 1502.

[4] http://www.next-tip.com/

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One of the factors that limit the spatial resolution in Atomic Force Microscopy (AFM) is the physical size of the probe. This limitation is particularly severe when the imaged structures are comparable in size to the tip's apex. The resolution in AFM is usually enhanced by using sharp tips with high aspect ratios. In this talk we present modified AFM tips based on a new method for both the functionalization and the reduction of the final radius of the tips that can be used in scanning probe microscopies (SPM). This approach to modify AFM tips consists in depositing nanoclusters on standard silicon tips. We will explain the modification process of the AFM tips [1] and present some examples comparing images acquired with the modified tips with SuperSharp tips.

In a previous work [2] we demonstrated that the modified tips improved the aspect ratio and the lateral resolution of standard tips. In this work an additional comparison with SuperSharp tips is performed. Figure 1 presents a comparison of a nanoparticuled system measured exactly in the same region. It can be observed how the NPs are better resolved with the modified tips. We know from previous studies that these nanoparticles presented a round shape. The ratio between the width and the height of the nanoparticles, measured in the attractive regime, presented around a 37 % reduction when using the modified tips. When performing similar experiments on single wall carbon nanotubes, SWCNT; (figure 2), we also observed a reduction of the measured width (see profile). In addition to this, we will present some other examples to prove how by the modification of standard tips with nanoparticles it is possible to improve also the spatial resolution of SuperSharp tips. This modification has a long lasting effect and the durability of the tips is larger

Lidia Martínez J. R. Ramos E. Román R. García and Y. Huttel

SPM 2013

Oral

Figures

Figure 1: AFM images (300x300 nm2) of Au nanoparticles deposited on a Si(100). The left image was acquired with a commercial SuperSharp tip and the center image with a modified tip. In the right image is displayed a comparison profile of two nanoparticles.

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Figure 2: AFM images (200x200 nm2) of SWCNT deposited on a Si(100). The left image was acquired with a commercial SuperSharp tip and the center image with a modified tip. A comparison profile is presented in the right image.

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Ni cluster on HOPG: Growth Mode and Electronic Properties studied by STM

Michael Marz¹·² R. Hofmann-Vogel² K. Sagisaka¹ and D. Fujita¹

¹National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan ²Karlsruhe Institute of Technology (KIT), Kaiserstraße 12, 76131 Karlsruhe, Germany

Michael.Marz @k it.edu

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randomly distributed on the basal plane. For higher coverage, the Ni-clusters showed the tendency to cluster. However, after annealing, a significant change in the shape and size occurred.

A stepwise procedure was used to study the details of the annealing process, where the temperature was raised in 100K steps up to 870K. Already the first annealing step at approximately 450K led to the formation of single crystalline clusters. This single crystalline structure was furthermore observed for all other used annealing temperatures, an example is shown in the inset of figure 2a. While the width of the clusters was not affected by the annealing, their height continuously increased for temperature higher than 550K. We ascribe this behavior to diffusion, which can be divided into two different regimes: First, at low annealing temperature mainly an atomic rearrangement takes place. Second, for higher temperature, whole clusters can diffuse on the HOPG surface. On the other hand, we found a reproducible way for picking-up individual clusters from the surface for both kind, as grown and annealed ones. So far we were not able to inverse the process, which means we are able to 'clean' the surface but can not fully manipulate the clusters.

Besides this topographic characterization, we carried out measurements of the electronic properties of the clusters by the means of currentvoltage measurements in a CITS experiments on individual clusters. The differential conductance was then derived by numerically differentiation of the currentvoltage signal. The overall shape of the current vs. voltage curve indicates a metallic behavior of the cluster. But we found a pronounced minimum in the differential conductance at the Fermi-edge for again both, non-annealed and annealed clusters. The averaged

531

Metallic nanoparticles are of growing interest owing to their great potential in applications and therefore, have been extensively investigated during the last two decades. Among others, they are especially useful for catalytic processes, where the total active surface is crucial [1]. Besides the importance of the application of the clusters, such small nanoparticles consisting of only a few atoms up to a several hundreds of atoms represent the crossover between isolated atoms and bulk, and are consequently interesting for fundamental research.

We will present a scanning tunneling microscopy (STM) study on Ni-clusters grown by depositing Ni under UHV condition on highly ordered pyrolytic graphite (HOPG), as reported in [2,3]. It is worth mentioning that a similar method was recently used to grow graphene on individual Ni islands [4], and for the growth of large area single and multilayer graphene on Ni [5]. STM permits the investigation of electronic properties through scanning tunneling spectroscopy (STS) and current imaging tunneling spectroscopy (CITS), in addition to the topographic properties of the nanoparticles, e.g. the size and the shape. All measurements were performed in an UHV-STM at liquid nitrogen temperature.

We investigated the dependence of the size, shape, and distribution of the clusters on the deposition parameters, namely deposition time, deposition rate, as well as, the HOPG mosaic spread and subsequent annealing. After deposition of Ni onto the 'cold' HOPG surface, the formed clusters showed a cloud like shape, as it can be seen in the inset of figure 1a. The shape and size of the cluster did not depend on neither the deposition parameters nor the mosaic spread of the substrate. For low coverage, the clusters grew preferentially along step edges, but appeared

SPM 2013

Oral

signals for various squares on the HOPG background (black) and the Ni-clusters (blue) are shown in figures 1a and 2a. Furthermore, all clusters display an enhanced signal at roughly 400mV along the edge of the cluster. The resulting CITS maps for selected voltages are displayed in figures 1b and 2b.

References [1] A. Z. Moshfegh, Journal of Physics D: Applied Physics 42 (2009) 233001.

[2] M. B채umer et al., Surf. Sci., 327 (1996) 321.

[3] Z. Bastl et al., Nanotechnology, 17 (2006) 1492.

[4] Y. Murata, et al., ACS Nano 4 (2010) 6509.

[5] M. Xu, et al.,ACS Nano 5 (2011) 1522.

Figures

(1a) non-annealed cluster

(2a) annealed cluster

Electronic properties of (left) non-annealed and (right) annealed cluster derived from CTIS measurements. The dl/dV graphs are calculated by numerical differentiation of the current-voltage curves that have been averaged over the rectangular areas marked in the topography image. For completeness the averaged current vs. voltage results are also given as inset. The measurements obtained on the HOPG substrate are plotted in black and display the typical spectra of HOPG. The results measured on the Ni-clusters are shoen in blue. For both, as grown and annealed clusters a significant minimum at the Fermi level can be found.

(1b) selectic CTIS maps at constant bias as marked in (1a)

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(2b) selectic CTIS maps at constant bias as marked in (2b)

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STM identification of N-doped nanoarchitectures formed by onsurface (cyclo) dehydrogenation of heteroaromatics

Javier Méndez A. L. Pinardi, J. I. Martinez G. Otero-Irurueta, M. Tello M. F. López and J. A. Martín-Gago

SPM 2013

Oral

jmendez@icmm.csic.es Instituto de Ciencia de Materiales de Madrid ((ICMM), Consejo Superior de Investigaciones Científicas (CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain

ImagineNano2013

images with theoretical ones calculated using a Keldysh–Green function formalism, together with the first-principles tight-binding Hamiltonian obtained from the local-orbital DFT-Fireball method allow us to present a chemical route for the transformation of a molecule upon dehydrogenation.

The theory-experiment agreement in the apparent height determination of STM features from different molecular nanostructures can be a valid methodology for identification at the nanoscale.

References [1] Méndez, J.; López, M. F.; Martín-Gago, J. A. Chem. Soc. Rev 40 (2011) 45783001.

[2] Otero, G.; Biddau, G.; Sánchez-Sánchez, C.; Caillard, R.; López, M. F.; Rogero, C.; Palomares, F. J.; Cabello, N.; Basanta, M. A.; Ortega, J.; Méndez, J.; Echavarren, A. M.; Pérez, R.; Gómez-Lor, B.; Martín-Gago, J. A. Nature 454 (2008) 865.

[3] A.L. Pinardi et al. ACS Nano in press.

Figures

533

Surface-assisted cyclodehydrogenation and dehydrogenative polymerisation of polycyclic (hetero)aromatic hydrocarbons (PAH) are among the most important strategies for bottom-up assembly of new nanostructures from their molecular building blocks [1]. Although diverse compounds have been formed in recent years using this methodology, a limited knowledge on the molecular machinery operating at the nanoscale has prevented a rational control of the reaction outcome. By controlling the diffusion of N-heteroaromatic precursors, the on-surface dehydrogenation can either lead to monomolecular triazafullerenes [2] and diazahexabenzocoronenes (N-doped nanographene), to N-doped oligomeric or polymeric networks, or to carbonaceous monolayers [3]. Governing the on-surface dehydrogenation process is a step forward towards the tailored fabrication of molecular 2D nanoarchitectures distinct to graphene and exhibiting new properties of fundamental and technological interest.

A significant progress in this area has been enabled by ultra-high vacuum scanning tunneling microscopy (UHV STM), which is a suitable technique for imaging nano-objects with ultimately intramolecular resolution. In this work we combine advanced in-situ surface characterization techniques as STM, near edge x-ray adsorption fine structure (NEXAFS) and high-resolution x-ray photoemission spectroscopy (XPS) with theoretical ab-initio calculations including van der Waals (vdW) forces to yield a complete understanding of the self-assembling of molecular precursors on surfaces.

Particularly, in this contribution we show that an adequate combination of STM experimental

Invited From High-speed AFM to 4π AFM

1 2

1

R. Harniman1, D.J. Phillips1 L.M. Picco1, O. Payton1 M. Antognozzi1, S. Simpson1 S. Hanna1, D.J. Engledew1 G. Gibson2, R. Bowman2 and M.J. Padgett2

Nanoscience & Quantum Information Centre, University of Bristol, U.K School of Physics and Astronomy, University of Glasgow, U.K.

Three areas in which conventional AFM has limitations: (i) low imaging rate, (ii) probe-sample force interaction, and (iii) the planar nature of the sample.

We are developing two high-speed force microscopy techniques. One high-speed AFM (HS AFM) technique is a DC method in which the tip is in continuous contact with the specimen. This routinely allows video-rate imaging (30 frames per second, fps) and has achieved imaging at over 1000 fps, i.e., 100,000 times faster than conventional AFM. Damage to specimens resulting from this high-speed contact mode imaging is surprisingly less than would be caused at normal speeds. The behavior of the cantilever and tip at these high velocities has been investigated and superlubricity is a key component in the success of this technique.

The other high-speed force microscope is a noncontact method based on shearforce microscopy (ShFM). In this HS ShFM, a vertically-mounted laterally-oscillating probe detects the sample surface at about 1 nm from it as a result of the change in the mechanical properties of the water confined between the probe tip and the sample.

With this technique, very low normal forces are applied to the specimen.

AFMs require planar samples because the probe scans in a plane. It is as if the tip is only ‘seeing’ the sample from above. We have overcome this limitation be steering the tip of a nanorod in a three dimensional scan with six degrees of freedom using holographically generated traps such that it is possible to scan around a sample.

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Mervyn Miles

Figures

Fletcher J, Harniman R, Anotgnozzi M, Miles MJ, Woolfson D, Science 339 (2013).

Phillips DB, et al., Nanotechnology 22 (2011) Art. No. 285503.

Olof SN et al., Nano Letters 12 (2012) 6018-6023.

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Disentangling atomic contrast on bimodal atomic force microscopy and simultaneous scanning tunneling microscopy on the TiO2(101) anatase surface 1

International Center for Young Scientists (ICYS), National Institute for Materials Science (NIMS), 1-21 Sengen Tsukuba, Ibaraki 305-0047, Japan 2 National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan 3 Universidad Autónoma de Madrid (UAM), 28049 Madrid, Spain 4 Institute of Chemical Research of Catalonia (ICIQ), Avda. Països Catalans 16, Tarragona, Spain # Corresponding Author, Tel: +81 (0) 29-859-3945

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MORENOSIERRA.Cesar@nims.go.jp

oscillation amplitudes (typically between 8 to 40 pm), and therefore, it is very sensitive to the short-range tip-surface interaction force [12]. In this presentation we will show how the combination of the different channels of information provided by simultaneous bimodal AFM/STM operation allows us to clarify the contribution of the different atomic species of the TiO2(101) anatase surface to the atomic resolution images. This is further corroborated by the study of the bonding structure of molecular water on the TiO2(101) anatase surface. We will also show that the average tunneling current enables to pinpoint subsurface defects that are otherwise unrevealed in the topographic AFM images (Fig. 1).

References [1] Wendt et al.,Science, 320, (2008) 1755-1759.

[2] Matthey et al., Science, 315, (2007) 16921696.

[3] Enevoldsen, et al.,Phys. Rev. B 78, (2008) 045416.

[4] Bechstein, et al., Nanotechnology 20, (2009) 505703.

[5] Hebenstreit et al., Physical Review B 62, (2000) R16334.

[6] Gong et al., Nature Materials 5, (2006) 665.

[7] He et al., Physical Review Letters 102, (2009) 106105.

[8] He et al., Nature Materials 8, (2009) 585.

[9] Grinter et al., J. Phys. Chem. C 116, (2012) 11643.

[10] Sawada et al., Appl. Phys. Lett. 94, (2009) 173117.

[11] Kawai et al., Physical Review Letters 103, (2009) 220801.

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Titanium dioxide (TiO2) is a highly strategic material with important applications in energyrelated developments, including photocatalytic production of hydrogen and solar energy conversion schemes. Since most of the peculiar TiO2 properties are surface-mediated, a deep understanding of the TiO2 surface properties is presented as critical issue to develop highperformance applications. Probably, the most studied TiO2 form is rutile because it was one of the first bulk single crystal displaying high quality surfaces at reasonable prices. Rutile surfaces has been extensively studied at atomic scale over several decades with both scanning tunneling microscopy (STM) [1,2] and atomic force microscopy (AFM) [3,4]. However, TiO2 anatase has superior performance than rutile in several energy harvesting related issues. At variance with the rutile structure, very few experimental studies on large single crystals of anatase exist, and the structure [5,6], intrinsic defects [7], and phenomenology [8,9] of the TiO2 anatase surfaces are still not very well understood.

Here, we present an atomic scale characterization of the TiO2(101) anatase surface by means of bimodal AFM and simultaneous STM measurements (Fig.1). By using Pt-Ir covered cantilevers, we are able to detect the average tunneling current flowing between the cantilever and a conductive sample while performing atomic resolution dynamic AFM [10]. Simultaneously, it is also possible to operate AFM in bimodal mode [11]. In this work, we use the variation of the resonant frequency of the first eigenmode of a rectangular cantilever to acquire topographic images while simultaneously detecting the variation of the resonant frequency of the second eigenmode, which is driven at ultra-small

1,2#

César Moreno 2 3 O. Stetsovych , M. Todorovíc 4 4 J. W. Ryan , E. Palomares R. Pérez3 and 2 O. Custance

SPM 2013

Invited

[12] Giessibl, Reviews of Modern Physics 75, (2003) 949.

Figures

536

Figure 1: Atomic scale characterization of the titanium dioxide (101) anatase surface: (left) AFM topographic image and (right) corresponding average tunneling current image recorded simultaneously by bimodal AFM/STM. The rectangle in both images marks the same surface region for reference

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The surge of a Kondo lattice in atomic scale structures

1,2

María Moro 1,2 D. Serrate 1,3 M. Piantek J. I. Pascual 1,4 and 1,2 M. R. Ibarra

SPM 2013

Oral

1

Instituto de Nanociencia de Aragón (INA) and Laboratory for Advanced Microscopy (LMA), University of Zaragoza, Spain 2 Dpto. Física de Materia Condensada, University of Zaragoza, Spain 3 Instituto de Ciencias de Materiales de Aragón (ICMA), University of Zaragoza-CSIC, Spain 4 Nanoscience Cooperative Research Center (CIC Nanogune)

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with the same number of neighbors but with topographically frustrated spin, the Kondo temperature does not show the same behaviour.

References [1] [2] [3] [4] [5]

S. Loth, et al. Science 335, 196 (2012).

Y. Jiang et al. Science 333, 324 (2011).

N. Tsukahara et al.,PRL 106, (2011).

P.Simon et al., PRL 94 (2005).

A.F.Otte et al., PRL 103 (2009).

Figures

Figure 1: Left: Topography image (Vbias=-20 mV, It=15 pA ) of a four Co atoms chain separated two Ag(111) interatomic distances( 0.58nm). Right: STS performed in the atoms reveal a 1.5 meV broadening of the Kondo resonance.

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Nanomagnets of atomic scale are promising devices for future technology [1]. In the development of the spin-based technology, the understanding of the interactions between magnetic impurities and the conduction electrons of the substrate is of crucial importance. The magnetic properties of single magnetic atoms on metals are inherently connected with many body interactions between the localized magnetic moment and the supporting surface. The Kondo effect is the one most frequently found. Using scanning tunneling microscopy we have developed a method to perform 2D-imaging of the Kondo resonance over Co magnetic impurities on Ag(111).

Starting with a single atom (Kondo screening length, ξk=0.7 nm) we have characterized the Kondo cloud as a function of the number of nearest neighbors and their separation with atomic-scale control.

We have observed a transition in the overall magnetic coupling between atoms separated by three Ag(111) interatomic distances (0.87nm) to impurities separated two atomic distances (0.58nm) where the corresponding Kondo clouds interfere owing to the interaction [2,3] through the conduction electrons of the metal host (Ruderman-KittelKasuya-Yosida interaction).

We have further addressed the competition between RKKY interactions and the Kondo liquid regime of such artificial structures. In linear atomic chains, scanning tunneling spectroscopy shows that the Kondo resonance of atoms with two neighbors is broadened by 1.3 meV (15K). In the RKKY mediated antiferromagnetic regime this broadening has been theoretically predicted [4], and experimentally assigned to a spin splitting of the otherwise degenerated doublet responsible for the Kondo phase [5] (fig.1). In contrast, for atoms

mmoro@unizar.es

Invited Inducing new molecular properties at the metallic interface

Aitor Mugarza

Catalan institute of Nanotechnology (ICN), UAB Campus, E-08193 Bellaterra

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The electronic and magnetic properties of organic compounds are in most cases strongly modified by the presence of a metallic interface [1]. The dramatic effect of the bonding configuration at the interface is in fact the responsible for the lack of reproducibility in the transport properties of molecular junctions [2]. On the other hand the metallic interface offers the possibility to induce new molecular charge and spin configurations.

Understanding the correlation between conformational and spectroscopic properties at the atomic scale is therefore fundamental to control the properties of molecular junctions, and the STM represents an ideal tool for such investigation.

Here we show how a careful choice of moleculemetal interaction can lead to interesting phenomena such as the induction of chiral molecular orbitals in achiral molecules [3], and of magnetism in organic compounds [4]. Using single metal-phthalocyanines deposited on Ag(100), we see that both effects depend on the central metal ion, which determines the active orbitals [5]. In the case of spin induction, the spatial localization of the Kondo resonance we observe indicates that the new spin belongs to a ligand orbital and coexists with that of the central transition metal ion. Magnetic excitations of the coupled spins contribute to the inelastic tunnelling, from which we can determine the magnetic ground state and intramolecular exchange coupling energy. Finally, we explore several methods to manipulate the charge and spin configuration by moving individual molecules in order to form intermolecular bonds or alkali atoms to electron-dope the molecules [6].

Atom by atom doping results in a manifold of charge and spin configurations, where the amount of charge is controlled by the dual donor/acceptor

capability of the substrate and its localization in metal or ligand orbitals depends on the bonding site. The presented results highlight the need of considering the molecule-metal interface as a functional, active part of molecular junctions.

References [1] S. Sanvito, Chem. Soc. Rev. 40, 3336 (2011).

[2] L. Bogani and W. Wernsdorfer, Nat. Mater. 7, 179 (2008).

[3] A. Mugarza et al., Phys. Rev. Lett. 105, 115702 (2010).

[4] A. Mugarza et al., Nature Comm. 2:490 (2011).

[5] A. Mugarza et al., Phys. Rev. B 85, 155437 (2012).

[6] C. Krull et al., Nature Mater. 12, 337 (2013)

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AFM electrical characterization of graphene nanoLEDs

1

Instituto de Ciencia de Materiales de Madrid (ICMM). Consejo Superior de Investigaciones Científicas (CSIC). Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain 2 ISOM Instituto de Sistemas Optoelectronicos y Microtecnologia, Universidad Politecnica de Madrid, Av. Complutense s/n. Madrid 28040. Spain

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cmunuera@icmm.csic.es javier.martinez@upm.es

grow the nanocolumns (NCs). With different conditions, one can create NCs with diverse doping (n or p) creating nanoLEDs. These devices are coated with a layer of SiO2 as isolator. Finally, on top we deposit a layer of graphene as transparent electrode.

The electrical transport properties of the graphene/GaN junction have been characterized by means of conductive Scanning Force Microscopy (c-SFM) measurements. The formation and rupture of nanocontacts is achieved by using the SFM probe as a movable top electrode to individually contact the graphene-covered GaN nanocolumns (Figure 1).

By combining multidimensional spectroscopy data acquisition [6] we have studied the influence of the loading force on the current versus voltage characteristics and identified the critical load at which a stable junction is formed and reproducible IV curves are obtained (Figure 2). Analysis of the measured IV curves is performed to extract the relevant parameters (barrier height, ideality factor) of the nanojunction.

References [1] B. Luo, S. Liu, L. Zhi, Small 8 (2012) 630.

[2] M. D. Stoller, S. Park, Y. Zhu, J. An, R. S. Ruoff, Nano Letter, 8 (2008) 3498.

[3] X. Cao, Y. Shi, W. Shi, G. Lu, X. Huang, Q. Yan, Q. Zhang, and H. Zhang, Small 7 (2011) 3163.

[4] G. Jo, M. Choe, C. Y. Cho, J. H. Kim, W. Park, S. Lee, W. K. Hong, T. W. Kim, S. J. Park, B. H. Hong, Y. H. Kahng, T. Lee, Nanotechnology 21 (2010) 175201.

[5] H. Park, J. A. Rowehl, K. K. Kim, V. Bulovic, J. Kong, Nanotechnology 21 (2010) 505204.

[6] Perez-Garcia et al., Nano Letters, 7 (2007) 1505.

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Graphene has attracted increasing attention in recent years [1] due to its excellent mechanical, optical and electrical properties. Its high theoretical surface area (2630 m2g-1) and high electrical conductivity make it an attractive material for many industrial applications [2]. Also it is a flexible transparent material that can be used for sensors, solar cells, light emitting diodes (LEDs) and organic LEDS (OLEDs), touchscreens and liquid crystal displays (LCD) [3].

A layer of graphene can be prepared by several techniques: mechanical exfoliation from graphite, precipitation on a silicon carbide surface, reduction of exfoliated graphene oxide, and chemical vapor deposition (CVD) growth on Cu or Ni. For electronics, the most used one is CVD, and the synthesized graphene is commonly grown on a flat metal foil or thin film and transferred to the desired substrate by sping coating of PMMA. In general, the transparent conducting electrode used for the light emitting diodes (LEDs) is the indium tin oxide (ITO), but this material has a high cost and is unstable in the presence of acids or bases and has poor transparency in the blue and near-infrared light ranges [4]. Furthermore the need to replace ITO is even increasing due to the limited availability of indium on earth [5].

Graphene is the ideal candidate in order to replace the ITO due to its excellent electrical, optical and mechanical properties. So in this work we used graphene as a transparent electrode as a top contact in the nanoLEDs. All the nanostructures were created in a 2 inch wafer of GaN over a sapphire substrate (Lumilog, France). The sample was patterned by colloidal lithography using 100 nm polystyrene nanospheres and a thin layer of 10 nm of Ti was deposit on top.

After removing the nanospheres, the sample was inserted inside a plasma assisted MBE in order to

1

Carmen Munuera 1 M. García-Hernandez 2 A. Bengoechea-Encabo S. Albert2, M. A. Sanchez2 2 García , E. Calleja 2 F. Calle and 2 J. Martinez

SPM 2013

Oral

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Figure 1: a) Optical image of the graphenecovered and uncovered GaN regions. b) Topographic image of the graphene/GaN nanocolumns surface. c) Schematics of the c-SFM set-up.

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Figure 2: IV curves acquired on top of a graphene/GaN column as a function of the applied load.

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Mechanical Properties of DNA Nanografted Monolayer 1

INSTM â&#x20AC;&#x201C; ST Unit, Trieste, Italy Sincrotrone Trieste S.C.p.A., Trieste, Italy University of Trieste, Doctorate School in Nanotechnology, Trieste 4 International School of Advanced Studies (SISSA), Italy 5 Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, USA 6 University of Udine, Department of Medical and Biological Sciences, Italy

1,2

Pietro Parisse 2,3 M. D. Nkoua Ngavouka 2,4 A. Bosco C. Micheletti4 5 A. Vindigni 2,6 G. Scoles and 1,2 L. Casalis

SPM 2013

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References [1] E. Mirmontaz, M. Castronovo, C. Grunwald, F. Bano, D. Scaini, A.A. Ensafi, G. Scoles, L. Casalis, Nanoletters 8, 4134 (2008) 4134.

[2] F. Bano, L. Fruk, B. Sanavio, M. Glettenberg, L. Casalis, C.M. Niemeyer, G. Scoles, Nanoletters 9, 2614 (2009).

[3] A. Bosco, F. Bano, P. Parisse, L. Casalis, A. DeSimone, and C. Micheletti, Nanoscale 4, 1734 (2012).

[4] P. Parisse, A. Vindigni, G. Scoles and L. Casalis, The Journal of Physical Chemistry Letters, 3, 3532 (2012).

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Nanografted monolayers (NAMs) of short oligonucleotides sequences (18-60 bps) show novel properties that make them ideally suited for advanced biosensing applications [1,2]. Due to their small size and the high homogeneity of the DNA surface coverage, they allow for extreme miniaturization and for ultrasensitivity. In order to optimize the performances of NAM-based devices, however, a thorough understanding of the physical-chemical properties of these systems is required.

Analyzing the mechanical response of DNA NAMs to the force exerted by an AFM (Atomic Force Microscope) tip by means of differential topographic height profiles in buffer solution and parallel coarse-grain modeling of the DNA nanostructures, we were able to estimate the NAM surface coverage and correlate it to the hybridization efficiency [3]. Also, we studied the dependence of the NAM height on the ionic strength of the solution, in order to optimize the responsiveness to hybridization events.

The different mechanical response of ss- and dsDNA NAMs, connected to their different flexibility, has been further exploited to investigate the reaction mechanism of helicases, which are accounted for strand separation in ds-DNA. We monitored the differential height variation of engineered dsDNA NAMs as a function of the enzyme incubation time, for two different, homologous helicases, the bacterial RecQ and the human RecQ1, highlighting different kinetic behaviors for these enzymes, and providing the first estimate of RecQ1 unwinding rate [4].

pietro.parisse@elettra.trieste.it

Invited Forces and Photons in Molecular Tunneling Junctions

Jose Ignacio Pascual

CIC nanoGune, Tolosa Hiribidea 78, San Sebastian – Donostia 20018, Spain Ikerbasque, Basque foundation for Science, Bilbao 48011, Spain.

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STM is an ideal probe to investigate electronic structure and excitations of individual adsorbates on surfaces. Combination of energy, space and time resolution is a powerful approach to track elementary processes involved in fields like chemistry, molecular electronics, magnetism,…

Bringing the tip of a STM to contact a molecule allows us to also investigate charge transport through molecular junctions in a controlled configuration. In this talk, I will present our results regarding the formation and measurement of electronic transport through conjugated polymers hosted between a clean metal surface and the tip of the STM. We combine electron transport measurements with two additional experimental techniques to obtain additional information, simultaneously to differential conductance measurements: i) Force spectroscopy, revealing the intramolecular flexibility and deformations occurring during the formation of a molecular junction and ii) Light spectroscopy, which provides an insight into vibrational temperature induced by inelastic electrons.

- The measurement of forces at the atomic scale is done by attaching the STM tip to a stiff resonator.

Interaction forces and energy can be sensed with high resolution. When investigating a molecular junction, the measurement of forces simultaneously to electrical transport, provides a new insight into the effect of molecular deformations in molecular conductance.

- Tunneling electrons also induce light emission mediated by field-enhanced plasmons at the tunnel junction. The spectroscopic characterization of emitted photons reveals “anti-stokes”-like phenomena, which we interpret as induced by hot molecular modes, excited by inelastic tunneling.

Figures

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Different contrasts in atomically resolved scanning force microscopy images of Si(111) 7x7

Carmen Pérez León H. Drees M. Marz and R. Hoffmann-Vogel

Karlsruhe Institute of Technology (KIT), Kaiserstrase 12, 76131 Karlsruhe, Germany

Carmen.Perez.Leon@kit.edu

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perpendicular to the surface and forms a dangling bond [5]. Covalent bonding interactions between undercoordinated atoms and unsaturated dangling bonds from the semiconductor surface and the tip are responsible for this atomic resolution [2].

Here, we present the results of our SFM investigations on the Si(111) 7x7 reconstructed surface at RT. We used the FM mode, in which the cantilever is oscillated at its resonance frequency while keeping an oscillation amplitude constant of few nanometers (<10nm). Two feedbak loops keep such magnitudes constant. The signal used to produce the topographic images comes from the forces acting on the tip which are detected as deviations in the cantilever resonant frequency.

The typical atomically resolved SFM of Si(111) images show the 12 protruding adatoms and a corner hole for every unit cell. In some cases, also the observance of the restatoms has been reported. However, in our atomic resolved experiments not only the expected images are reproduced, but also several different contrasts are found. The Si(111) surface was crosschecked with STM measurements that proved that the surface was (7x7) reconstructed. For the interpretation of our results, the other parameter images recorded simultaneously, such as the frequency shift, the dissipation, and the current are used for obtaining the correspondence of the structures observed with the DAS model. The different kind of images can be classified as follows: Normal contrasts: 1- imaging of the adatoms. This is the typical SFM image, similar to STM image for V>0 (empty states) with the 12 adatoms and a corner hole per unit cell, see Figure (a)&(b); 2- imaging of adatoms plus restatoms. This image

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Among scanning probe microscopies, scanning force microscopy (SFM), in particular in its dynamic mode under the frequency-modulation detection method (FM-DSFM), has shown to be a powerful tool for investigating the topography of both, conducting and insulating surfaces, at the nanometer scale. Owing to the high degree of complexity of the FM-DSFM instrumentation, atomic resolution was only obtained around ten years after its invention. For resolving atoms with the SFM microscope, the short-range forces related with the interaction of the foremost atom at the end of the cantilever and the atoms at the surface have to be detected [1,2]. These forces depend on the chemical and physical nature of both the tip apex and of the nearby sample atoms [3], and become appreciable at very close distances between the tip and the surface (typically <5 A). But the chemical and physical nature of the tip of the cantilever is often modified during the experiment (crashes, picking or losing atoms), making complicated the interpretation of the images obtained [3]. Additionally, long-range forces are also present, in vacuum they mainly correspond to the van der Waals force, the electrostatic force, and magnetic-dipole interactions. If the magnitude of the long-range forces is significant at close tip–surface distances, obtaining atomic resolution can become difficult [1]. Si(111) is the standard surface used in many surface science techniques, including SFM. The complex structure of the 7x7 reconstruction is described by the dimer adatom stacking-faulted model (DAS model) proposed by Takayanagi et al.

[4]. The uppermost layer consists of six adatoms in each half of the unit cell. These adatoms are bound by covalent bonds formed by 3sp3 hybrid orbitals.

One of the four 3sp3 hybrid orbitals is pointing

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is also similar to STM image but in this case for V<0 (filled states) with the 12 adatoms plus a weak signal of the 6 restatoms and a corner hole, Figure (c); 3- imaging of the restatoms. The 6 subsurface restatoms and a corner hole are imaged. No signal of the adatoms is measured although they are still there, like they would be transparent, see Figure (d).

Inverted contrasts: 4- complementary image: the “holes” between adatoms are imaged as protrusions. The corner holes look as brigther protrusions, whereas the ones between the restatoms look darker, see Figure (e); 5- complementary image with darker corner holes.

In these images the protrusions have all the same appearance but the corner holes look again dark.

Different protrusions and corner holes shapes are observed, sometimes circular, sometimes more star-shaped, see Figure (f)&(g); 6- bright corner holes. Again adatoms are resolved as protrusions, but some of them are not visible since the corner holes appear very bright and larger that their original size covering them, see Figure(h).

For the SFM experiments silicon cantilevers were used, some of them were coated with PtIr. Different treatments were applied to the cantilevers: in some cases we dipped them in organic solvents before introducing it into the vacuum chamber. In UHV, the majority of the tips were heated to 140oC, and for some experiments the cantilevers were sputtered in order to remove their native oxide layer. In general, the images were measured with a value of the bias that compensated the contact potential difference between the tip and the semiconductor surface. A switch between some of the contrasts was possible by only changing the frequency shift, i.e., by changing the distance to the surface.

The shape and nature of the tip together with its changes produced during scanning resulted in various kinds of interactions with the semiconductor surface giving rise to different contrasts. These are not only produced by a strange tip, since they have been reproduced with several cantilevers.

References [1] Óscar Custance, Rubén Pérez and Seizo Morita, Nature Nanotechnology, 4 (2009) 803.

[2] Ricardo García and Rubén Pérez, Surface Science Reports, 47 (2002) 197.

[3] M.A. Lantz, H.J. Hug, R. Hoffmann, S.Martin, A.Baratoff, and H.-J. Güntherodt, Physical Review B 68 (2003) 035324.

[4] K. Takayanagi, Y. Tanishiro, S. Takahashi, J. Vac. Sci. Technol. A, 3 (1985) 1502.

[5] Franz J. Giessibl, S. Hembacher, H. Bielefeldt, J. Mannhart, Science, 289 (2000) 422.

Figures

Figure 1: Different contrasts in the FM-AFM images Normal contrasts: (a)&(b) adatoms; (c) adatoms + restatoms; (d) restatoms.

Inverted contrasts: (e) complementary; (f) & (g) complementary + dark corner holes; (h) bright corner holes. Images size 7 x7 nm2.

DAS model is superimposed on the FM-AFM images.

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Strategies to investigate biological objects with success using piezoelectric tuning fork Atomic Force Microscopy

J茅r么me Polesel

SPM 2013

Invited

jerome.polesel@cea.fr

CEA Saclay, IRAMIS, Service de Physique et Chimie des Surfaces et Interfaces, F-91191 Gif-sur-Yvette, France

Piezoelectric quartz tuning fork has drawn the attention of many researchers for the development of new Atomic Force Microscope (AFM) self-sensing probes. Indeed, compared to silicon cantilevers used in conventional AFM, the tuning fork do not require the laser optical beam deflection technique which could induced signal artefacts and drift, and could be harmful to the scanned sample in some cases. Moreover, the high stiffness of tuning forks allows the AFM scanning with lower oscillation amplitudes than a cantilever which would offer a better sensitivity as shown by F. J. Giessibl (2001). However, using such selfsensing AFM probe is especially challenging when it concerns biological soft sample. Thus, we will discuss about the strategies to demonstrate the efficacy of this self-sensing AFM probe to perform high resolution imaging and force spectroscopy of biological objects in air and in aqueous media.

Figures

Figure 1: (a) Close view of a tuning fork AFM probe operating in a buffer droplet. (b) and (c): AFM topography mapping of individual IgM antibodies with respectively pentameric and hexameric structures.

References

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[1] A. Makky, Th. Berthelot, C. Feraudet-Tarisse, H. Volland, P. Viel, J. Polesel-Maris, "Substructures High Resolution Imaging of Individual IgG and IgM Antibodies with Piezoelectric Tuning Fork Atomic Force Microscopy", Sensors and Actuators B: Chemical 162(1), 269-277 (2012).

[2] J. Polesel-Maris, J. Legrand, Th. Berthelot, A. Garcia, P. Viel, A. Makky, S. Palacin, "Force Spectroscopy by Dynamic Atomic Force Microscopy on Bovine Serum Albumin proteins changing the tip hydrophobicity, with piezoelectric tuning fork self-sensing scanning probe", Sensors and Actuators B: Chemical 161(1), 775-783 (2012).

Oral The role of the bias voltage and the atomic thermal movements on the STM/FM-AFM images: how is a Si tetramer observed on the Si(111)-7×7 surface?

1

Pablo. Pou 1 1 L. Rodrigo , R. Pérez 2 2 P. Mutombo , P. Jelínek Y. Sugimoto3 3 3 M. Abe and S. Morita

pablo.pou@uam.es

1

Dpto. de Física Teórica de la Materia Condensada, Univ. Autónoma de Madrid, Spain 2 Inst. of Phys., Academy of Sciences of the Czech Republic, Prague, 16200, Czech Republic 3 IGraduate School of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan

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It is well known that both bias voltage and dynamical effects should be taken into consideration on the interpretation of STM images [1,2]. In this work we present a combined experimental and theoretical study on the influence of the bias voltage and the atomic thermal movements on both the STM and the FMAFM images of a Si tetramer on the Si(111)-7x7 surface [3].

Using the FM-AFM atomic manipulation ability [4] we have built up the Si tetramer. Topographic STM, CITS and constant high simultaneous FMAFM/STM images at RT show the Si4 atoms forming a symmetric structure (Fig. 1). Numerical simulations based on DFT show that the system is bistable, there are two solutions characterized by a rhombohedral tetramer with one of the atoms protruding over the other three (Fig. 1c). The corresponding STM simulated image displays this asymmetric structure. Molecular dynamic as well as energy barrier calculations disclose that, at RT, the tetramer is moving between the two solutions.

LT-STM experiments shows the two stable solutions at low voltages (< 0.3 eV) but recover the symmetric tetramer at bias larger than 0.7 eV. Therefore, RT-STM or high-voltage STM images are in fact an average of the two atomic configurations of the bistable system resulting in images displaying a symmetric structure. Explanation of the FM-AFM measurements is more complicate, simulations shows how not only the thermal or voltage-induced fluctuations but also the tipsurface interaction are playing an important role: at long tip-surface distances SR forces are negligible -no Δf contrast, standard STM image-, but at closer distances the outermost apex atom attracts its closer surface atom fixing the fluctuating tetramer in a particular solution (with that closer atom being the higher of the tetramer),

consequently both FM-AFM and STM images show the symmetric “on atom” solution.

References [1] J. Avila et al, Phys. Rev. Lett. 82, 442-445 (1999).

[2] B.C. Stipe, et al, Phys. Rev. Lett. 78, 4410 (1997).

[3] H. Tanaka et al., Jpn. J. Appl. Phys. 33, 366 (1994).

[4] Y. Sugimoto et al, Phys. Rev. Lett. 98, 106104 (2007).

Figures

Figure 1: a) RT-STM show a symmetric “on atom” structure for empty states and a cross-like image for the filled ones. b) Constant high simultaneous FM-AFM/STM for negative bias: STM images evolve for the cross-like structure to the “on atom” image upon tipsurface approximation. c) The asymmetric atomic structure calculated with the DFT method.

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Coupling adatoms or molecules to magnetic surfaces: a scanning tunneling spectroscopy study

Vincent Repain 1 L. Kawahara 1 1 J. Lagoute , C. Chacon Y. Girard1, S. Rousset1 2 A. Smogunov and 2 C. Barreteau

1

vincent.repain@univ-paris-diderot.fr

MP , UniversitĂŠParis iderot, Paris 7, CNRS, UMR 7162, Paris 13, France DSM/IRAMIS/SPCSI, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France

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molecule in contact with the magnetic surface states of the Cr(001) surface (cf. Fig. 1) [3]. This hybridized molecular state is responsible for an inversion of sign of the tunneling magnetoresistance depending on energy. This result opens the way to spin filtering through molecular orbitals

References [1] S. L. Kawahara, J. Lagoute, V. Repain, C. Chacon, Y. Girard, J. Klein, and S. Rousset, Phys. Rev. B 82 (2010) 020406.

[2] J. Lagoute, S. L. Kawahara, C. Chacon, V. Repain, Y. Girard, and S. Rousset, J. Phys.

Cond. Matt. 23 (2011) 045007.

[3] S. L. Kawahara, J. Lagoute, V. Repain, C. Chacon, Y. Girard, S. Rousset, A. Smogunov, and C. Barreteau Nano Lett. 12 (2012) 4558.

Figures

Figure 1: 3D STM image of single C60 molecules deposited on a chromium surface. The color scale indicates the local tunnel magneto-conductance. The tip of the microscope, the chromium surface and buckyballs are also schematized for clarity.

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The understanding of the coupling between discrete electronic states and a continuum is the key issue of transport through nanometer size conductors in general and for molecular electronics in particular. Up to now, this coupling has been mainly studied, especially at the nanometer scale, with non spin polarized continuums. However, the interaction of ultimate nano-objects like single atoms or molecules with a spin-polarized electronic bath (i.e. magnetic material) can be of particular interest both to better understand this coupling and for spintronics applications. In this talk, I will show two examples of such systems, studied by scanning tunneling spectroscopy.

Firstly, I will describe the Kondo resonance induced by a single cobalt adatom interacting with a ferromagnetic iron nanocluster, measured by lowtemperature scanning tunneling microscopy. The persistence of the Kondo resonance is evidenced along with the predicted splitting of the spectral density peak for a Kondo impurity surrounded by a spin-polarized electron bath. Reversible quenching of the split feature is observed using atom manipulation between adjacent adsorption sites.

Using a Greenâ&#x20AC;&#x2122;s-function formalism, we model a double Fano resonance leading to a quantitative insight of our observations [1].

Secondly, I will present spin-polarized scanning tunneling microscopy of the antiferromagnetic Cr(001) surface [2], discussing by comparison with ab initio calculations the origin of its different magnetic surface states. In a next step, I will show how, coupling state-of-the-art spin-polarized scanning tunneling spectroscopy and spin-resolved ab initio calculations, we have demonstrated the first experimental evidence of the spin splitting of a molecular orbital on a single non magnetic C60

SPM 2013

Invited

Invited 1,3

Nano-Scale Confinement in Superconductors: A Scanning Tunneling Spectroscopy Study

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Dimitri Roditchev 1 1 Ch. Brun , T. Cren 1 1 L. Serrier-Garcia , S. Pons V. Cherkez1, D. Fokin2 1 and F. Debontridder

Institut des Nanosciences de Paris, Université Pierre et Marie Curie UPMC and C.N.R.S.-UMR 7588, 4 place Jussieu, 75252 Paris, France.

2 Joint Institute for High Temperatures, RAS 125412, Moscow, Russia.

3 LPEM-UMR8213/CNRS-ESPCI ParisTech-UPMC, 10 rue Vauquelin-75005 Paris, France.

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The most famous macroscopic quantum phenomenon - superconductivity - is characterized by a nanometer-length scale, called coherence length ξ, at which the superconducting condensate may continuously evolve in space. The confinement of a superconducting material to scales comparable to ξ should substantially modify the superconducting properties. We addressed the problem of confinement in superconductivity by choosing a quasi-ideal model system – Pb atoms deposited in-situ on atomically clean surface of Si(111). Depending on growth conditions, we are able to produce superconducting Pb-nano-crystals of various sizes and shapes, but also to reach the ultimate thickness limit when only a singe atomic layer of Pb exists at Si-surface. We studied the superconductivity in these artificial materials by Scanning Tunneling Spectroscopy in UHV at low temperatures down to 0.3K, and under magnetic fields up to 8T. We will first discuss the simplest case of a vortex lattice weakly confined in relatively large superconducting samples ≈10ξ. We will show how the increasing confinement influences the vortex lattice, leading to novel ultra-dense configurations, impossible in bulk superconductors [1]. At even higher confinement, ≈3-4ξ, the Giant Vortices - quantum tornados characterized by a multiple phase accumulation L x 2π, L = 2; 3; 4 - are experimentally revealed, and their unusual cores probed [2].

In the second part of the lecture we will discuss the electron confinement effects, i.e. the cases when the carriers are spatially confined to kF-1.

We will present how the superconductivity evolves with the reduction of Pb-film thickness down to a single atomic layer limit [3]. In the latter case, the electronic properties become extremely sensitive

dimitri.roditchev@insp.jussieu.fr

to the precise structure of the Pb/Si interface, and may result in an insulating, metallic or superconducting behaviour. In superconducting samples, such tiny and usually ‘inoffensive’ defects as single atomic surface steps or stacking faults disrupt the superconducting order. The samples become a nanometer-scale network of atomic superconducting terraces weakly connected by native Josephson links at steps and stacking faults.

Keywords: superconductivity at nanoscale, confinement in superconductivity, vortex network, giant vortex, proximity effect in superconductors, Josephson vortex, STM/STS. References [1] Cren, T., et al., Phys. Rev. Lett. 102, 127005 (2009).

[2] Cren, T., Serrier-Garcia L., D., Debontridder et al., Phys. Rev. Lett. 107, 097202 (2011).

[3] Brun, C., Serrier-Garcia L., Cren, T., et al., Phys.

Rev. Lett. (2013) to appear.

Figures

Figure 1: STM-image (600nm x 600nm) of the studied system. The network consists of mono-atomic terraces of Si-substrate covered by non-superconducting wetting layer of Pb (in blue) and superconducting Pb-nano-islands few monolayer thick (greenyellow-orange). Rich island geometry provides a variety of landscapes confining quantum vortices.

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Bonding and self-organization of functionalized macrocycles: carboxylic versus pyrrole groups 1

Centro de Física de Materiales (CSIC-UPV/EHU), Material Physics Center (MPC), San Sebastián, Spain Donostia International Physics Center (DIPC), San Sebastian, Spain IKERBASQUE, Basque Foundation for Science, Bilbao, Spain 4 Departamento de Física de Materiales UPV/EHU, Facultad de Química, San Sebastián, Spain 5 Universidad Autónoma de Madrid, Instituto Nicolás Cabrera, Madrid, Spain.

6 Instituto de Ciencia de Materiales de Madrid (ICMM –CSIC), Madrid, Spain 7 Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-NANO), Madrid, Spain.

8 Istituto Officina dei Materiali (CNR-IOM), Laboratorio TASC,Trieste, Italy 9 Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland 10 Centro de Astrobiología, (INTA-CSIC), Torrejón de Ardoz, Madrid, Spain 2

Celia Rogero

1,2

R. González-Moreno1,2 A. GarcíaLekue2,3 A. Arnau1,2,4, M. Trelka5 J. M. Gallego6,7, R. Otero5,7 A. Verdini8, C. Sánchez-Sánchez9 P. L. de Andrés2,6 and J. A. Martín-Gago6,10

SPM 2013

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the protoporphyrin on a metallic surface, promoting the ring lifting, and promote the formation of strong chemical bond with the surface. Molecules are organized in such a way that the linker part of each molecule is buried under the macrocycle of the adjacent molecule.

Such a distinct behaviour of these Protoporphyrin molecules might be ascribed to the carboxyl groups, which act as buffers and significantly weaken the interaction of the ring with the surface. This result confirms the conclusion that peripheral groups are extremely relevant for the organization of molecules on metal surfaces. In parallel to this effect, due to the Cu surface the free-metal tetrapyrrole rings self-metalates with the Cu surfaces atoms changing from free-metal Protoporphyrin IX molecules, H2PPIX, to Cuprotoporphyrin molecules, CuPPIX, and this happens at room temperature.[5]

References [1] R. Gon le -Moreno, P.L. Cook, I. Zegkinoglou, X. Liu, P.S. Johnson, W. Yang, R.E. Ruther, R.J. Hamers, R.n. Tena-Zaera, F.J. Himpsel, J.E. Ortega, C. Rogero, The Journal of Physical Chemistry C, 115 (2011) 18195-18201.

[2] A. Rienzo, L.C. Mayor, G. Magnano, C.J. Satterley, E. Ataman, J. Schnadt, K. Schulte, J.N. O'Shea, Journal of Chemical Physics, 132 (2010) 084703.

[3] J. Chen, R.E. Ruther, Y. Tan, L.M. Bishop, R.J. Hamers, Langmuir, 28 (2012) 10437-10445.

[4] A. Garcia-Lekue, R. González-Moreno, S. Garcia-Gil, D.F. Pickup, L. Floreano, A. Verdini, A. Cossaro, J.A. Martín-Gago, A. Arnau, C. Rogero, Journal of Physical Chemistry C, 116 (2012) 15378-15384.

549

Our work is framed in understanding the interactions of typical dye organic molecules with metal-substrates, paying special attention to the role played by the functional group. We study the influence of the chemistry in the organization process of the macrocycles, particularly of porphyrin molecules. For that purpose we combine scanning tunnelling microscopy (STM), X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS), with abinitio calculations to analyze the interaction of sublimated protoporphyrins IX (H2PPIX) molecules, with a single crystal surface as Cu(110) surface in ultra high vacuum conditions (UHV) at room temperature.

Ideal single crystal surfaces are useful for modelling and understanding the possible interactions for further applications in more complex systems. The choice of H2PPIX among all porphyrins molecules was motivated by two factors. First its structural simplicity, i.e., an almost planar geometry, which facilitates studying the behaviour of the central macrocycle ring in the proximity of the surface. Second, H2PPIX are tetrapyrrole molecules functionalyzed with two propionic acids. These carboxylic acid groups provide solid anchoring for real devices.[1-3] The functional groups play a critical role determining the properties of a molecular overlayer. They control the stability, molecular arrangements and electronic properties. In this work, by the complementary information extracted from the experimental and the theoretical results we determine the carboxylic acid groups govern the intermolecular interaction at low temperature [4] and the surface-molecule interaction at room temperature. Moreover, the presence of the carboxylic acid groups importantly modify the kind of ordered structure formed by

celia_rogero@ehu.es

[5] R. González-Moreno, C. Sánchez-Sánchez, M. Trelka, R. Otero, A. Cossaro, A. Verdini, L. Floreano, M. Ruiz-Bermejo, A. García-Lekue, J.A. Martín-Gago, C. Rogero, Journal of Physical Chemistry C, 115 (2011) 6849-6854.

Figures

550

Figure 1: Summary of the main chemical and structural changes of the protoporphyrins IX molecules on Cu(110). At low temperatures there is a random molecular distribution stabilized by coordinated H bonds between carboxylic and tetrapyrrole rings of adjacent molecules. At room temperature the molecules in contact with the substrate suffer irreversible molecular transformations, mainly deprotonation of the carboxylic groups and self-metalation of the pyrroline subunits. The carboxylate groups act as anchored group.

ImagineNano2013

Synchrotron X-ray Scanning Tunneling Microscopy

Volker Rose

SPM 2013

Invited

vrose@anl.gov Advanced Photon Source and Center for Nanoscale Materials, Argonne National Laboratory, 9700 S Cass Ave, Argonne, Illinois 60439, USA

In this talk we will discuss the development of a novel high-resolution microscopy technique for imaging of nanoscale materials with chemical, electronic, and magnetic contrast [1,2]. It will combine the sub-nanometer spatial resolution of scanning tunneling microscopy (STM) with the chemical, electronic, and magnetic sensitivity of synchrotron radiation [3]. Drawing upon experience from a prototype that has been developed at the Advanced Photon Source to demonstrate general feasibility, current work has the goal to drastically increase the spatial resolution of existing state-of-the-art x-ray microscopy from only tens of nanometers down to atomic resolution. Key enabler for high resolution is the development of insulator-coated “smart tips” with small conducting apex (Figure 1) [4].

After entirely coating sharp tips with insulating films, the coating can be removed from the apex by means of high-resolution focused ion beam milling. Such tips drastically reduce the background of photoejected electrons that would otherwise cause an undesired signal at the sidewall of the tip. The novel microcopy technique will enable fundamentally new methods of characterization, which will be applied to the study of energy materials and nanoscale magnetic systems. A better understanding of these phenomena at the nanoscale has great potential to improve the conversion efficiency of quantum energy devices and lead to advances in future data storage applications.

Grant SC70705. Work at the Advanced Photon Source, the Center for Nanoscale Materials, and the Electron Microscopy Center was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract DEAC02-06CH11357. http://www.aps.anl.gov/Xray_Science_Division/Sxspm/

References [1] V. Rose, J.W. Freeland, S.K. Streiffer, “New Capabilities at the Interface of X-rays and Scanning Tunneling Microscopy”, in Scanning Probe Microscopy of Functional Materials: Nanoscale Imaging and Spectroscopy, S.V. Kalinin, A. Gruverman, (Eds.), Springer, New York (2011), pg 405-432.

[2] M.L. Cummings, T.Y. Chien, C. Preissner, V. Madhavan, D. Diesing, M. Bode, J.W. Freeland, V. Rose, Ultramicroscopy 112, 22 (2012).

[3] V. Rose, T.Y. Chien, J.W. Freeland, D. Rosenmann, J. Hiller, V. Metlushko, J. Appl.

Phys. 111, 07E304 (2012).

[4] V. Rose, T.Y. Chien, J. Hiller, D. Rosenmann, R.P. Winarski, Appl. Phys. Lett. 99, 173102 (2011).

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551

Acknowledgements: The author acknowledges generous funding by the Office of Science Early Career Research Program through the Division of Scientific User Facilities, Office of Basic Energy Sciences of the U.S. Department of Energy through

Figures

552

Figure 1: X-ray nanotomography surface rendering of a smart scanning tunneling microscope tip. The platinum-iridium tip (red) has been coated with a SiO2 insulating layer (green). Image obtained using the Center for Nanoscale Materials Hard X-Ray Nanoprobe beamline at Sector 26 of the Advanced Photon Source, USA.

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Adsorption of tetrathifulvalene (TTF) on Cu(100): can π-stacked 1-D aggregates be formed at low temperature?

1,2

Ane Sarasola 3 S. Monturet 4 S. Barja A. L. Vázquez de Parga4 and 1,5 A. Arnau

SPM 2013

Oral

1

Departamento de Física Aplicada I, UPV/EHU, Bilbao Donostia International Physics Center, San Sebastián CEMES-CNRS, 29 rue Jeanne Marvig, BP 94347, 31055 Toulouse Cedex 4, France 4 Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia) and Dep. Física de la Materia Condensada, UAM, Cantoblanco 28048, Madrid 5 Departamento de Física de Materiales, Facultad de Química UPV/EHU and Centro de Física de Materiales CFM Centro Mixto CSIC-UPV, San Sebastián 2

ane.sarasola@ehu.es

3

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our energetic analysis suggests the existence of a weakly attractive substrate mediated interaction.

However, both the adsorption energy and the intermolecular attraction are rather weak (a few hundred meV) and, therefore, the existence of these particular TTF aggregates is restricted to low temperatures

References [1] D. Sánchez-Portal, S. Riikonen, and R. M. Martin, Phys. Rev. Lett. 93, (2004) 146803.

[2] N. Gonzalez-Lakunza, I. Fernández-Torrente, K. J. franke, N. Lorente, A. Arnau, and J. I. Pascual, Phys. Rev. Lett. 100 (2008) 156805.

[3] M.-L. Bocquet, H. Lesnard, and N. Lorente, Phys. Rev. Lett. 96 (2006) 096101.

[4] M. Trelka, Ch. Urban, C. Rogero, P. de Mendoza, E. Mateo-Martin, Y. Wang, I. Silanes, D. Écija, M. Alcamí, F. Yndurain, A. Arnau, F. martin, A. M. Echevarren, J. A. Martín-Gago, J. M. Gallego, R. Otero, and R. Miranda, CrystEngComm 13 (2011) 5591.

[5] M. Feng, P. Cabrera-Sanfelix, Chungwei Lin, A. Arnau, D. Sánchez-Portal, Jin Zhao, P. M. Echenique, and H. Petek, ACS Nano vol. 5, No. 11 (2011) pp. 8877-8883.

553

The possibility of growing one-dimensional (1-D) chains of π-stacked molecules, like TTF, on surfaces represents a challenge that would permit the study of fundamental electronic properties in conducting 1-D systems as an alternative to, for example, those formed by 1-D rows of Au atoms on Si vicinal surfaces [1]. Usually, the adsorption geometry of planar organic molecules, like polyarenes, on single crystal surfaces is essentially parallel to the surface [2], as the bonding is typically due to the interaction between the π electron cloud and the surface electrons. As a consequence of this adsorption geometry, there is no π-stacking between the molecules, as in the molecular crystals. However, there are exceptional cases in which the molecules are adsorbed vertically on the surface, no matter whether it is a single crystal surface, due to the formation of a particular molecule-surface bond [3] or the existence of an unusual intermolecular bonding [4]. So far, its practical realization using semiconductor or insulating surfaces does not seem to be an easy task but metal surfaces represent a first alternative to explore although, in principle, it is unclear which type surface is better: a highly anisotropic quasi-1D surface, like O(2x1)/Cu(110) [5], or a more isotropic 2-D Cu(100) surface.

In this work we use first principles calculations to study the adsorption energy of TTF molecules on Cu(100) and explore the reasons why at low temperature STM topographical images seem to show the formation of one dimensional aggregates of π-stacked molecules. At low coverages, the energetically favoured adsorption geometry corresponds to planar TTF molecules parallel to the Cu(100) surface, while at high coverages a metastable phase with a tilted adsorption geometry appears to be stabilized by intermolecular van der Waals forces. Furthermore,

Figures

554

Figure 1: (Left) Low temperature (T=4.6 K) STM image (7x7 nm) of the Cu(100) surface at low TTF coverage. The green curve encloses a TTF tetramer that appears with brighter contrast in the image, as compared to the TTF monomer. (Right) Schematic representation of the adsorption geometry. Our DFT-vdW calculations suggest a planar adsorption geometry for the TTF monomer, while a tilted adsorption geometry in the one-dimensional TTF aggregate. This different adsorption geometry is due to intermolecular van der Waals attraction and the existence of a weak substrate mediated attractive interaction between TTFs.

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C60-Cox complex built by atomic/molecular manipulation using low temperature scanning tunneling microscopy and its physical properties studied by tunneling spectroscopy

Peng Yang J. Lagoute V. Repain C. Chacon-Carillo Y. Girard and S. Rousset

SPM 2013

Oral

peng.yang@univ-paris-diderot.fr

Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot et CNRS, UMR 7162, Case courrier 7021, 75205 Paris Cedex 13, France

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most only slightly affected by the interaction between the molecule and the Co atoms.

References [1] L. Gross, K.-H. Rieder, F. Moresco, S. M. Stojkovic, A. Gourdon, and C. Joachim, Nat. Mater., 4 (2005), 892.

[2] J. Repp, G. Meyer, S. Paavilainen, F. E. Olsson, and M. Persson, Science, 312 (2006), 1196.

[3] R. Yamachika, M. Grobis, A. Wachowiak, and M. F. Crommie, Science, 304 (2004), 281.

[4] . L. Kawahara, J. Lagoute, V. Repain, C. Chacon, Y. Girard, S. Rousset, A. Smogunov, and C. Barreteau, Nano Lett., 12 (2012), 4558.

[5] M. Gobbi, F. Golmar, R. Llopis, F. Casanova, and L. E. Hueso, Adv. Mater., 23 (2011), 1609.

Figures

Figure 1: Left, the C60 molecules (bigger spots) and the Co atoms (smaller spots) on the Au(111) surface; Middle, Formation of C 60-Co complex; Right, The movement of C60-Co complex. The dashed squares guide the eyes by indicating the initial position of C 60 molecule.

555

Understanding of the electronic process at the interface and the interaction between the organic molecule and metal at atomic/molecular scale is critical to build the new generation molecule electronic devices. Moreover, atom manipulation using scanning tunneling microscopy (STM) allows the formation of atomic controlled artificial molecule-metal conjugate [1–3]. As the interface between C60 molecule and magnetic material holds promises for molecular spin electronics [4,5], we studied the interaction between C60 molecule and Co atoms. Using a low temperature (LT) STM and scanning tunneling spectroscopy (STS), we manipulate atoms and molecules to build C60-Cox complex and study its physical properties.

The Co atoms and C60 molecules are deposited insitu on a clean Au(111)/mica surface in ultra-high vacuum (<10-10mbar) at low temperature (5K).

We show that it is possible to move a C60 molecule above a Co adatom and then manipulate the molecule-atom ensemble as a single object, suggesting that we formed a Co-C60 complex (Figure 1). Moreover C60-Cox entities with x>1 can be formed by a combined lateral manipulation of C60 molecule and Co adatoms in two different ways: the molecule is successively moved towards individual adatoms, or a Cox cluster is built by atomic manipulation then the molecule is moved towards the cluster. We have been able to add up to 9 Co atoms to a C60 molecule, which is, to our knowledge, the largest number achieved in such molecule-metal atom complex.

We performed dI/dU spectroscopy using the lockin technique in order to measure the influence of Co on the molecular spectrum. Although possible doping effect still need to be clarified, the C60-Cox spectrum exhibit the main features of the C60 single molecule suggesting that the pi states are at

Oral A Molecular Platinum Cluster Junction: A Single-Molecule Switch

Universidad Aut贸noma de Madrid, Cantoblanco, Madrid, Spain

We present a theoretical study of the electronic transport through single-molecule junctions incorporating a Pt6 metal cluster bound within an organic framework ((SC4S)2Pt6). In a previous experimental study [1] it was suggested that the presence of the Pt6 cluster creates an indentation in the potential barrier, giving a molecular analog of an inorganic double tunnelling barrier. This was, however, a speculative argument which was never fully proven, and neither was the nature of these states identified. In this study, we show that the insertion of this molecule between a pair of electrodes leads to a fully atomically engineered nano-metallic device with high conductance at the Fermi level and two sequential high on/off switching states [2]. The origin of this property can be traced back to the existence of a HOMO which consists of two degenerate and asymmetric orbitals, lying close in energy to the Fermi level of the metallic leads. Their degeneracy is broken when the molecule is contacted to the leads, giving rise to two resonances which become pinned close to the Fermi level and display destructive interference due to multiple electronic pathways through the molecule. These states, however, do not stem from the Pt unit alone, but specifically from two apical Pt atoms and their neighboring S atoms

Linda A. Zotti E. Leary M. Soriano J. C. Cuevas and J. J. Palacios linda.zotti@uam.es

[2] L. A. Zotti, E. Leary, M. Soriano, J. C. Cuevas, and J. J. Palacios, J. Am. Chem. Soc., 135 (2013), 2052.

Figures

Figure 1: Optimized geometry of ((SC4S)2Pt6 with its two degenerate HOMO orbitals.

Figure 2: (SC4S)2Pt6 embedded between two gold clusters.

References

556

[1] Leary, E.; van Zalinge, H.; Higgins, S. J.; Nichols, R. J.; de Biani, F. F.; Leoni, P.; Marchetti, L.; Zanello, P. Phys. Chem. Chem. Phys., 11 (2009), 5198.

Figure 3: Transmission as a function of energy for (SC4S)2Pt6 and for an alkyl chain of the same length (C18)

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NanoSD

2013

Index NanoSD2013 Contributions Invited

Pag

■ Jérôme Bourderionnet (THALES TRT, France) "Nanophotonics structures for signal processing in Radar systems"

565

■ Antonio Hernando (Univ. Complutense, Spain) Magnetic Microwires as elements for radar absorber"

568

■ Meyya Meyyapan (NASA, USA) "Nano Chemical and Radiation Sensors"

571

■ Claudia Simão (ICN2, Spain) "Dimension and positional metrology approaches in nanotechnology"

581

■ Jean-Pierre Simonato (LITEN CEA, Grenoble, France) "Detection of Neurotoxic Gases by Functionalized Silicon Nanowire Field-Effect Transistors"

582

■ Mark Welland (University of Cambridge, UK) -

Abstrat not provided by the speaker

Oral

Pag

■ Santiago Alvarez de Cienfuegos (Micromag, Spain) "Developing a Military-Grade Disruptive Technology"

563

■ Yaser Essa (AERNNOVA, Spain) "Nano Surface Engineering in Thermal Shields for Planet Re-entry"

566

■ Juan José Fernández (Industria Química del Nalón, Spain) "High Performance Nano-sized Materials. The Power of Nano"

567

■ Francisco Martín Julián (AIN, Spain) "Electrically Conductive Polypropylene fibers"

569

■ María Monteserín Leiva (AIN, Spain) "Antibacterial textiles based on Poly-Pyrrol Nanocoatings"

572

■ Nieves Murillo (Tecnalia, Spain) "Smart Nanofiber Filters for Personal Protection"

574

■ Maria Pilar Pina (INA – University of Zaragoza, Spain) "Enhanced Nitroderivates Detection with Si Microcantilevers by using Sorption Heat on Microporous Materials as Additional Discriminating Tool"

576

■ Luis Roca (Aimplas, Spain) "Plastics and Nanomaterials, new approaches for advanced properties"

578

■ Idoia Sancet (TECNAN, Spain)

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579

559

"Applications of TECNAN Nanoproducts in security and defense"

Index NanoSD2013 Contributions Alphabetical Order I:Invited / O: Oral

Pag

■ Santiago Alvarez de Cienfuegos (Micromag, Spain) "Developing a Military-Grade Disruptive Technology"

O

563

I

565

O

566

O

567

I

568

O

569

I

571

O

572

O

574

O

576

O

578

O

579

I

581

I

582

I

-

■ Jérôme Bourderionnet (THALES TRT, France) "Nanophotonics structures for signal processing in Radar systems"

■ Yaser Essa (AERNNOVA, Spain) "Nano Surface Engineering in Thermal Shields for Planet Re-entry"

■ Juan José Fernández (Industria Química del Nalón, Spain) "High Performance Nano-sized Materials. The Power of Nano"

■ Antonio Hernando (Univ. Complutense, Spain) Magnetic Microwires as elements for radar absorber"

■ Francisco Martín Julián (AIN, Spain) "Electrically Conductive Polypropylene fibers"

■ Meyya Meyyapan (NASA, USA) "Nano Chemical and Radiation Sensors"

■ María Monteserín Leiva (AIN, Spain) "Antibacterial textiles based on Poly-Pyrrol Nanocoatings"

■ Nieves Murillo (Tecnalia, Spain) "Smart Nanofiber Filters for Personal Protection"

■ Maria Pilar Pina (INA – University of Zaragoza, Spain) "Enhanced Nitroderivates Detection with Si Microcantilevers by using Sorption Heat on Microporous Materials as Additional Discriminating Tool"

■ Luis Roca (Aimplas, Spain) "Plastics and Nanomaterials, new approaches for advanced properties"

■ Idoia Sancet (TECNAN, Spain) "Applications of TECNAN Nanoproducts in security and defense"

■ Claudia Simão (Institut Català de Nanotecnologia, Spain) "Dimension and positional metrology approaches in nanotechnology"

■ Jean-Pierre Simonato (LITEN CEA, Grenoble, France) "Detection of Neurotoxic Gases by Functionalized Silicon Nanowire Field-Effect Transistors"

■ Mark Welland (University of Cambridge, UK)

560

Abstrat not provided by the speaker

ImagineNano2013

A b s t r ac t s Alphabetical order

NanoSD 2013

Oral

salvarez@micromag.es Micromag Jose Echegaray 8, Las Rozas - Madrid, Spain

This document briefly describes the research and development process on disruptive technologies and specifically in those targeting Military & Defense non-transparent market Military market has been, mainly due to high investment and long returns, a golden mine for long time on regards to innovation and cutting edge technology deployment. Is somehow familiar for all the industrial communities of certain advancements in Military Deployments are then transferred to the civil market on a dual use product and the likes. Investment and cutting edge technology usually go hand by hand in this sense, however, in Military and Defense markets, a line does not have to be the shortest path in between a disruptive innovation and a product commercial deployment.

What happens when customers reject a new technology, product concept, or way of doing business because it does not address their needs as effectively as a company’s current approach?

Does it necessarily mean that the technology or innovation is not suitable for market deployment?

Those, and many other questions, arise when thinking in innovating in the Military and Defense Space and especially on disruptive innovation. But before going in further detail let’s examine what is a disruptive innovation. An innovation is the process of translating an idea or invention into a good or service that creates value or for which customers will pay. In contrast, a disruptive innovation will bring a brand new value proposition to the marketplace. Usually this kind of innovation brings new features that customers will demand on the future, but no so much today.

What makes it even harder is that usually the performance in comparison with existing technologies is rather low. So with these two

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nanoSD 2013

Santiago Alvarez de Cienfuegos

characteristics, offering something that does not exist and not performing really well in comparison with existing solutions make this kind of innovation the hardest one [1]. Typically time to market is rather high, no one believes in it at the beginning and financing and development of such technologies is really difficult.

Particularly in these new environments there are common problems such as non-standardization, credibility, regulatory limitations and high cost associated with a new technology. It is the chicken and egg problem existing in any industry, either you bet for something or it simply disappears. It is not just to have the right product at the right timing but also to have the decision and leadership to make things happen. Most well-managed, established companies are consistently ahead of their industries in developing and commercializing new technologies— from incremental improvements to radically new approaches—as long as those technologies address the nextgeneration performance needs of their customers.

However, these same companies are rarely in the forefront of commercializing new technologies that don’t initially meet the needs of mainstream customers and appeal only to small or emerging markets.

Let’s examine why a disruptive technology is even harder to develop on Military and Defense environments. Usually in this type of markets the information on regards to the requirements is rather limited due to its very own nature. In any product having a clear view on what to develop is key for success, what happens when you do not have “directly” that kind of information? In these cases the R&D strategy should be able to accommodate new input variables throughout the whole lifespan of the process. Ability to re-

563

Developing a Military-Grade Disruptive Technology

engineering throughout the R&D process is key to success in these opaque environments.

Micromag has developed a disruptive Radar Absorbent Technology that took around 13 years to tweak and finalize. The development process covered from basic scientific research to fast prototyping and customization according to non – clear requirements. Curiously enough, it was even more complex to decrypt the unclear requirements in terms of performance than to develop them one the scientific basis were fully developed. Micromag ability to adjust the R&D process continuously with new input variables has been key to success. It has been also extremely relevant to be able to provide peace of mind in terms on one-on-one comparison with existing technologies and break the ever-existing “apple by apple” comparison. Also, experience has demonstrated how this type of technology has higher chances of success in small non-centered markets than in Tier 1 developed markets, usually because of hungriness of new solutions and risk assumption approaches from customers sitting in those environments.

References [1] Joseph L. Bower and Clayton M. Christensen.

Harvard business review January–February 1995 page 1.

564

Figures

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Nanophotonics structures for signal processing in Radar systems

Jérôme Bourderionnet S. Combrié and A. De Rossi

Thales Research & Technology, 1 avenue Augustin Fresnel, Palaiseau, France

jerome.bourderionnet@thalesgr oup.com

[1] J. Capmany, D. Novak, Nature Photonics, 1 (2007), pp. 319–330.

[2] J. Capmany, B. Ortega, D. Pastor, J. Lightw.

Technol., 24 (2006) pp. 201-229.

[3] Candy, J. V., Signal processing, the modern approach, McGraw-Hill, 1988.

[4] T.X.H. Huang, X. Yi, R.A. Minasian, Optics Express, 19 (2011), pp. 6231-6242.

[5] J. Sancho, J. Bourderionnet, J. Lloret, S. Combrié, I. Gasulla, S. Xavier, S. Sales, P. Colman, G. Lehoucq, D. Dolfi, J. Capmany, A. De Rossi, Nature Communications, 3 (2012), pp. 1075.

Figures

Delay (ps)

0

70ps

50 100 50 40

1530

30

1540

20 1550

10 0 1560

Tunable laser 1 Tunable laser 2 Tunable laser 3 Tunable laser 4

sin(t) IM

PhC dispersive delay line

Photodiode

sout(t)

Figure 1: 4 taps tunable MWP filter with a 1.5mm long III-V PhC waveguide dispersive delay line. Tunability demonstration with FSR from 40 to 70GHz by wavelength set tuning [5].

565

ImagineNano2013

References

4:1 combiner

Photonics is now part of the heart of modern radar systems, with already hundreds of optical links implemented in latest generation radars for analog and/or digital signal transportation from the antenna elements to the processing unit. Beside signal transportation, a decisive objective for radar and communication systems is to exploit photonics properties to perform more complex functions [1].

Photonics has proved for years its remarkable potential for manipulations of optically carried microwave signals, such as delaying, weighting, routing or sampling. Followed a considerable amount of implementations of microwave photonics signal processing [2]. A crucial functionality in a signal processing scheme is the microwave signal delaying, which is simply the physical implementation of the Z-transform [3]. A tunable delay line is achieved either by changing the light path length, for instance using chirped Bragg grating and tunable laser [4], or by exploiting a change in group index associated to a very strong dispersion. The last method is the most promising option towards integrated photonics signal processors, especially for radar front-end applications where lightweight, small volume and low consumption are mandatory.

Photonic crystal waveguide delay lines have recently reached performance levels, either in the available delay, the RF bandwidth, or losses standpoint that make these objects compatible with radar application requirements, and with a technological maturity that allows their integration in complex devices [5].

nanoSD 2013

Invited

Oral Nano Surface Engineering in Thermal Shields for Planet Re-entry

Yasser Essa M. A. Castillo Acero

miguelangel.castillo@aernnova.com

Av. Manoteras 20, Ed.B, 5th, Madrid, Spain http://www.aernnova.com

566

The nano materials offer a big potential for hight remperature pasivation protection. This paper presents the activities developed for an application on planet re-entry shielding. The high plasma temperatures developed are a very challenging requirement. Current state of the art is based on quite heavy ceramic plates. The feasibility of using nano- grapheme for this matter is demonstrated with the development, design, manufacturing and testing of coupon samples.

The high speed of a spacecraft during its re-entry is the origin of the high energies developed in the process. The external Earth atmospheric layers produce friction with the spacecraft and the result is the conversion of this energy to heat and plasma generation in the shock waves, critical specially on the spacecraft leading edges. The spacecrafts are covered by shielding materials to protect the spacecraft interiors and its occupants from these high reentry temperatures. These materials must fulfill the following requirements, also applicable to other security like applications:  Low Mass Density  Able to stand at a temperatures range from 110ºC to 1260ºC.  Able to achieve integrity under high and sever thermal gradients  Re-usable during at least 100 missions, typical Design Service Goal  Non cathalitic in relation to atmospheric plasma  High resistance to chemical erosion  High resistance to thermal shocking (hich mechanical failure properties and low Young modulus) In this paper a nano grapheme layer is developed to stand in fron of these requirements. Then coupons and samples have been manufactured

and successfully tested. The feasibility of further investigations and developments have been achieved.

References [1] “Ablation materials for atmospheric entry”, Leonard Roberts, Materials for Space Operations, NASA, 1962.

[2] “Inflatable Re-Entry Technologies: Flight Demonstration and Future Prospects”, L. Marraffa, D. Kassing, P. Baglioni, ESTEC, Noordwijk, The Netherlands. ESA bulletin 103 — august 2000.

[3] “Superior Thermal Conductivity of Single-Layer Graphene”, Alexander A. Balandin et al. Nano Letters. 2008. Vol. 8, No. 3. 902-907.

[4] “Surface energy engineering of grapheme”, Young Jun Shin, Journal National University of Singapore, 2009.

[5] “Large Area, Few-Layer Graphene Films on Arbitrary Substrates by Chemical Vapor Deposition”, Alfonso Reina et al, MIT Nano Letters, 2009, Publication Date (Web): 01 December 2008.

Downloaded from http://pubs.acs.org on February 14, 2009.

[6] “Effective Heat Transfer Properties of Graphene Sheet Nanocomposites and Comparison to Carbon Nanotube Nanocomposites”, Khoa Bui et al, The Journal of Physical Chemistry, American Chemical Society – ACS Publications 2011.

[7] “Processing of Nano Graphene Plates (NGPs) and NGP Nanocomposite”, Yena Li, Wright State University, 2007.

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Oral Juan José Fernández Rodríguez

juanjo@nalonchem.com Industrial Química del Nalón S.A. Avda. de Galicia 31, Bajo, 33005, Oviedo, Spain http://www.nalonchem.com

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

Reduction of current DLS particle size (35 – 40 nm) down to a mono-dispersion state in any sort of carrier fluid.

These nanoparticles have great potential as EMI shielding materials, hybrid polymers, printed electronics, surface coatings, transparent conductors, biotech materials, UV-absorbers, catalysts, etc

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Nanomaterials have been attracting much attention over the last the decade in the field of numerous functional materials. Their unique and unprecedented properties will definitely play a key role in the next generation of catalysts, ultraviolet absorbers, semiconductors, transparent conductors, cosmetics, coatings, solar cells, etc.

Only very few technologies offer the possibility to produce colloidal dispersions of nanoparticles having narrow size distributions and high available surface areas. This is accomplished by stabilizing the particles at their primary size with no formation of secondary or tertiary structures. To date most available technologies are dry powder techniques which generate large aggregates, being those difficult to formulate in solution. The resulting dispersions have much less effective surface area, thus defeating the purpose of nanotechnology itself.

At Industrial Química del Nalón S.A., an innovative, versatile and environmentally friendly technique is being developed to produce high performance nanoparticles in the form of nanosized metals, metal oxides or mixed metal oxides. This bottomup technology enables the continuous production of fully crystalline nanoparticles in dispersion with narrow size distributions and precise stoichiometries in a predictable manner and without post treatments.

Initial developments made possible the production of two kinds of pure nano-TiO2 (anatase) colloidal dispersions at different pH values and particle sizes for photocatalytic applications. Presently, efforts are focused on the following two developments:  Synthesis of CeO2, ZnO (nanoparticles or nanorods), silver and mixed ferrites.

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High Performance Nano-sized Materials. The Power of Nano

Invited Magnetic microwires as elements for radar absorber

Antonio Hernando

antonio.hernando@externos.adif.es

Instituto de Magnetismo Aplicado (UCM-ADIF-CSIC) and Departamento de FĂ­sica de Materiales (UCM). P.O.Box 155, Las Rozas, Madrid, 28230 Spain

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It is shown that magnetic metallic microwires composite media attenuates microwave reflection of metallic surfaces. We show how the distance to the metallic surface, as well as the length and volume fraction of microwires, determine the frequency of maximum absorption and the return loss level. Furthermore, we were able to fit the experimental results with a theoretical model based on Maxwell-Garnett mixing formula.

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Oral 1

Francisco Martin 1 M. MonteserĂ­n 1 G. G. Fuentes R. J. Rodriguez1 and 2 I. De Schrijver

1

Centre of Advanced Surface Engineering-AIN, C/ San Cosme y San DamiĂĄn S/N, 31191 Cordovilla-Pamplona, Spain.

2 Centexbel-Ghent, Technologiepark 7, BE-9052 Zwijnaarde, Belgium.

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that allows mass production of woven textiles. In good agreement with the high dispersion levels observed the conductivity and spinability of the material into fibers were better too.

We have observed a percolation threshold at 0.5% with a maximum conductivity of 70 S/m at 8% wt.

The different formulations can be extruded into fibers or tapes due to the small size of the clusters produced after the compounding method.

Different stretching rates of the tapes and fibers are obtained depending on the wt % of MWCNT in the composites. In good agreement with previous studies, alignment of the MWCNT along the fiber axial direction has been observed. In fact, alignment degree of MWCNT and deformation of clusters directly depends on the stretching forces applied during the extrusion of the fiber. An extensive characterization of the fiber and materials has been carried out (including SEM, XRD) to describe their internal structure and morphology. Macroscopic properties (MFI, DC and AC conductivities, roughness) have been also studied.

In conclusion, achieving a non-metallic and intrinsically conductive fiber is an appealing challenge with many applications in different fields. The ultrasonication assisted compounding method developed for thermoplastics (such as polypropylene) represents a promising alternative to improve the dispersion of the nanofiller within the polymeric matrices. This is especially indicated for very high end applications where a high performance of the product is expected using the minimum amount of filler necessary. In these particular scenarios, maximizing the outstanding properties of the nanofillers will represent the difference between success and failure.

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We report here the development of electrically conductive polypropylene-MWCNT fibers and tapes with conductivities up to 70 S/m.

Electrical conductor fibers and yarns are very desirable kind of materials in nanotechnology.

With the rapid development of electrical, and particularly electronics industry, flexible electrically conducting and semi-conducting materials are receiving a widespread attention.

These materials are playing a more and more important role in realizing lightweight, wireless and wearable interactive electronic textiles used in Smart Materials. They have also an important role in the development of EMI shielding textiles, which are used to avoid the exposition to electromagnetic waves. This is a particularly important problem to workers that are exposed to electromagnetic sources (such as antennas and power generation) and patients with pacemakers that can be confronted with some specific problems regarding EMI that might interfere with the pacemaker function.

Metallic fibers are expensive, more brittle and heavier than most textile fibers, making it difficult to produce homogenous blends and also they can suffer galvanic corrosion. It is also possible to impart electrical conductivity to commercial fibers by non-metallic conductive coatings. Nevertheless, intrinsically conductive fibers have a major advantage compare with the conductive fibers based on coated yarns because the former can not suffer from delamination, which clearly affects the electrical conductivity.

Using a solution compounding method assisted by sonication we have produced composite masterbatches (1Kg/batch) with improved MWCNT dispersion levels. These composites have been extruded into fibers by melt spinning which is a well implemented technique in textile industry

fmartinjulian@gmail.com

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Electrically Conductive Polypropylene fibers

References [1] P. Xue, X. Tao, M-Y. Leung and H. Zhang.

Wearable electronics and photonics.

Woodhead Publishing Ltd and CRC Press LLC. 2005, pp. 81.

[2] T.W. Chou, L. Gao. E. T. Thostenson et al.

Composites Science and Tecnology 2010, 70, 1.

[3] L.M. Ericson, H. Fan, HQ Peng et al. Science 2004, 305, 1447.

[4] J-K. Kim, P-C Ma, G. Marom et al. Composites: Part A 2010, 41, 1345.

Figures

Figure 1: Left: Electrical conductivity vs MWCNT %wt; right: SEM of fibers.

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Figure 2: SEM pictures form a 5% CNT composite. Left: Composite in powder form; right: Alignment of MWCNT along the fiber axial direction.

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Invited Meyya Meyyappan

m.meyyappan@nasa.gov NASA Ames Research Center Moffett Field, CA, USA

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Nano Chemical and Radiation Sensors

Single-wall carbon nanotubes (SWCNTs) exhibit a surface area as high as 1600 m2/g which is attractive for the adsorption of gases and vapors.

Gas adsorption can change SWCNTâ&#x20AC;&#x2122;s properties such as conductance, capacitance, dielectric constant etc, and measuring/monitoring one of these properties can then form the basis for gas/vapor sensing. Our group has constructed a chemiresistive sensor using SWCNTs with variations such as doping, metal loading, functionalization etc. A 1 cm x 1 cm chip typically consisting of 32 sensor elements is used with a pattern recognition algorithm in the operation of an electronic nose. Examples of gas and vapor sensing using this sensor array will be provided.

For radiation sensing, we use a silicon CMOS based approach. A vertical FINFET type device is used but the conventional SiO2 dielectric is replaced with a gel-like dieletric that responds to radiation. The device has been exposed to 1-100 kRad gamma radiation and the current-voltage characteristics change in a reproducible manner. In the long term, the gel can be replaced if it has undergone extensive damage and the device with replacement gel recovers its original characteristics.

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Aknowledges: The author acknowledges his colleagues Jing Li, Yijiang Lu and JinWoo Han

Oral Antibacterial textiles based on Poly Pyrrol Nanocoatings

María Monteserín F. Martín G. G. Fuentes and R. J. Rodriguez

mmonteserin@ain.es Centre of Advanced Surface Engineering-AIN_tech, Asociación de la Industria Navarra, Carretera de Pamplona, nº 1, C.P. 31191, Cordovilla, Spain

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The market of antibacterial textiles has gained increasing importance in the last few years. The growth of micro-organisms has negative effects on textiles, such as the generation of odour and stains, which is a particularly important problem in biomedical and technical textiles.

Nowadays, commercially-available antibacterial textiles usually use broad-spectrum biocides such as silver, quaternary ammonium compounds and triclosan as active agents [1]. However, recent studies have shown that silver nanoparticles are able to penetrate into the cells, damaging the genotype.

Besides, triclosan is a photo-reactive agent that is able to form chlorinated dioxins, toxic for waterliving organisms. Therefore, it is important to develop new materials for antibacterial textiles.

One of the main approaches in the development of alternative antibacterial materials is based in the presence of positively-charged molecules that disrupt the cell wall of the bacteria [1].

Polypyrrole, a widely known semi-conductive polymer, bases its conductivity on the dislocation of positive charges along its conjugated structure.

Textile fibers coated with chemically-synthesized polypyrrole have been shown to have antibacterial activity, although most part of it is lost during laundering [2].

In this work, plasma polymerized polypyrrole-like nanocoatings have been developed on textile yarns through RF plasma enhanced chemical vapour deposition (PE-CVD), which is a solventfree and environmentally friendly alternative technique. Plasma parameters such as power discharge, monomer flow, pressure, time and presence of gas carrier have been studied in order to obtain the best deposition conditions to get high conductivity and, therefore, the best antibacterial performance.

Although the

conductivity of the plasma polymerized polypyrrole is not as high as the one of the chemically synthesized polypyrrole, doping with iodine leads it conductive. Adhesion to the fibres has also been studied and improved through the use of argon plasma pre-treatment on the textile samples.

Plasma polymerized polypyrrole coatings have been characterized through conductivity, FT-IR, SEM and XPS measurements. Antibacterial activity against Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae of coated textiles have been evaluated following the international standard test methods: ASTM E 2149 and EN ISO 20645, dynamic and static methods, respectively. The antibacterial efficiency has been also studied after fastness tests simulating stresses to which the textiles are subjected during processing, maintenance and final use. Fastness has been evaluated following international standard test methods: laundering, dry-washing, abrasion, rubbing and fastness to perspiration.

References [1] Y. Gao, Textile Research Journal, 78, (2008), 60-72.

[2] A. Varesano, C. Vineis, A. Aluigi, F. Rombaldoni, "Antimicrobial polymers for textile products". In: A. Mendez- Vilas (Ed.), "Science against Microbial Pathogens: Communicating Current Research and Technological Advances, Vol. 3", Formatex, Microbiology Series Nº3, Vol. 1, Badajoz, Spain, pp. 99–110 (2011). ISBN-13: 978-84939843-1-1.

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Figure 1: SEM pictures from a poly-pyrrole coating deposited in cotton fabrics.

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Figures

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Figure 2: 3D images of AFM mapping carried out in tapping mode of 1.0 Îźm2 areas of polypyrrole coated substrates. Coating deposited at A) 10W and B) 100W, respectively.

Oral 1

Smart Nanofiber Filters for Personal Protection

Nieves Murillo 1 1 F. Seco , A. Perez 2 J. C. Cabria , P. Lorenzo Lozano2 2 and M. Gil García

1

TECNALIA, Pº Mikeletegi, 2. Parque Tecnológico, San Sebastian, Spain Instituto Tecnológico La Marañosa, Ctra San Martín de la Vega km 10,4, San Martín de la Vega (Madrid), Spain 2

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The objective of this work is to prove the retention efficacy and the elution of polycarbonate nanofibers against an aqueous suspension of Bacillus thurigensis spores (simulator of Bacillus anthracis) as well as to verify if there exists interference of the nanofibers with the detection techniques employed.

The electrospinning technology has been used to develop the polycarbonate nanofiber filter. In order to do so, a suitable solution of polycarbonate with appropriate solvents and other additives has to be developed with the suitable viscosity so that when subjected to a high potential difference between the solution and the place of deposition (collector) is applied nanofibers are produced and deposited in the form of a non-woven material.

The main difficulty of this work is related to finding the appropriate selection of process parameters, which are many and interrelated, and range from the polymer blend/solvent system ratios in the solution, required stabilisers, mixing time, applied voltage, flow rate, collector to needle tip distance, needle diameter and humidity. The best results were obtained with a solution composed of:  20% PC  DMF/THF (50/50 wt)  TBAC (1% wt with respect to PC)  Flow rate: 0,5 ml/h  V: 15 kV  Needle tip to collector distance: 150 mm  Needle diameter: 0.6 mm  Relative humidity: 30%  T-range: 23 ºC Figure 1 shows a shows a circular PC sample without beads (47 mm in diameter) successfully extracted from the Al foil that was used as a collector and figure 2 shows a SEM micrograph of the PC nanomesh obtained were it can be seen

nieves.murillo@tecnalia.com

that there is no presence of defects such a beads or excess solvent an the nanofibers show a quite uniform range of diameters that vary between 200-300 nm.

The number of microorganisms retained by the polycarbonate nanomesh was measured by comparing the ufc/ml of the stock solution with the ufc/ml of the filtered product using a kitasato flask to which a vacuum pump was attached.

Figure 3 shows the experimental setup. Counting was carried out using flow cytometry. Figure 4 shows number of viable spores counted for a standard nylon filter and the polycarbonate nanofiber filter after several washes. Almost all spores are recovered with the first wash. This is shown more clearly in figure 5 where the total number of spores found in the stock solution, the nylon filter and the polycarbonate nanofiber filter after the first wash is presented.

The main conclusions from this work are:  The polycarbonate nanofiber filter retains 99,6% of the Bacillus thuringiensis in the aqueous suspension.  The spore recovery from polycarbonate nanofiber filter, washing with PBS+0,05% Tween-20 is complete.  Polycarbonate nanofibers do not interfere with test techniques used in this study.

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Figures

Figure 1: Photograph showing a circular PC sample without beads (47 mm in diameter) successfully extracted from the Al foil.

Figure 4: Number of viable Bacillus thuringiensis spores counted for a standard nylon filter and the polycarbonate nanofiber filter after several washes.

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Figures

Figure 2: SEM micrograph of a PC nanomesh without beads.

Figure 5: Total number of Bacillus thuringiensis spores found in the stock solution, the nylon filter and the polycarbonate nanofiber filter after the first wash is presented.

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Figure 3: Experimental setup (A), nanofiber mesh in a Petri plate (B) and filtered product in a sterile Falcon tube.

Oral Enhanced Nitroderivates Detection with Si Microcantilevers by using Sorption Heat on Microporous Materials as Additional Discriminating Tool

1,2

Maria Pilar Pina 1 1 A. Peralta , I. Pellejero 1,3 M.A Urbiztondo J. Sesé1 and 1,2 J. Santamaría

mapina@unizar.es

1

Instituto de Nanociencia de Aragón (INA), Zaragoza, SPAIN Networking Research Center on Bioengineering, Biomaterials and Nanomedicine, (CIBERBBN), Zaragoza, SPAIN 3 Centro Universitario de la Defensa (CUD), Zaragoza, SPAIN 2

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This work deals with the vapor detection of explosives by easy to operate, low-cost, accurate and fast chemical sensors based on Si microcantilevers provied with internal heating and modified with nanoporous solids as chemical receptors. As a rough rule of thumb a method that is suitable for direct explosive detection should be able to detect explosives concentrations down to less than 1 ng/L. The progress achieved in the field of chemical sensors during the last decade has been truly outstanding, leading to a continuous lowering of sensitivity limits. This has been driven in large part by the development of cantileverbased sensors [1], and particularly by the advances in three main areas: smaller mechanical resonators, higher resonant frequencies and improved readout techniques to detect the motion. Regarding sensor selectivity, i.e., the ability of a sensor to discriminate among different analytes, advances have generally been achieved on an ad hoc basis, when a specific target has been identified for a certain analyte. However, this work puts forward a more realistic situation involving nanoporous solids [2-4], as chemical receptors that respond, at least partly, to more than one species.

To this end, zeolite type materials with tunable sorption properties have been deployed as isolated crystalline entities on the top surface of the mechanical transducers. Consequently, the strategy follows a biomimetic approach with the so-called artificial “nose” consisting of a chemical sensor array and a pattern recognition system. It is clear that a workable electronic nose requires miniaturization of its components, for economic as well as for practical (fast detection, regeneration times for efficient operation and system integration) reasons; a distinguished feature of the Si microcantilever array platforms herein used. The

cantilevers chips have been fabricated from n-type SOI (silicon on insulator) wafers by using standard optical lithography and bulk micromachining technologies with five-levels of masks. A multisensing platform comprising 8 microcantilevers per chip (Figure 1) with self-heating elements on the cantilever tips, and electromagnetic actuation and piezoresistive detection is proposed in this study for reproducible and reliable explosives detection. The use of meander shaped resistor (see Figure 1.b) is clearly beneficial for zeolite sorption capability refreshment with time on stream. The resonant frequency changes have been analyzed in presence of different concentration of toluene (13.5 mg/L3500 ppmV), water (2.1 mg/L- 2800 ppmV), and 2nitrotoluene (0.14 mg/L- 25 ppmV), vapors in dry N2. Detailed results obtained for two types of zeolite BEA (acid form denoted as HBEA & Fe exchanged type denoted as BEA-Fe) are depicted in Figure 2 and Figure 3 respectively. By using integrated heater, identical experiments have been performed at different temperatures on the cantilever tip (30ºC & 55ºC). Thus, additional finger prints of the same sample are obtained fulfilling time requirements. Unlike previous publications on explosives detection by following thermal signatures on microcalorimeter type cantilever sensors without chemical receptors [5], our sensing approach goes a step further in terms of reliability by using mass sensing as a function of temperature. The as calculated sorption heat values (Table 1), a distinguished feature of sorbate-sorbant interactions, could be used as additional key parameter for each of the Si coated cantilevers to improve false positive rates during explosives identification in complex environment.

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Aknowledges: Authors would like to acknowledge financial support from MICINN (CTQ2010-19276) Spain, DGA-CTP (CTPP11/11) and GICSERV actions in collaboration with IMB-CNM (CSIC).

References [1] A. Boisen, S. Dohn, S.S. Keller, S. Schmid, M. Tenje. Rep. Prog. Phys. 74 (2011) 036101/1.

[2] M. Urbitztondo, M.P Pina, J. Santamaría.

Ordered Porous Solids. Oxford: Elsevier (2009) 381.

[3] M. Urbiztondo, I. Pellejero, M. Villarroya, J. Sese, M.P. Pina, I. Dufour, J. Santamaria.

Sensors and Actuators B, 137 (2009) 608.

[4] M. Urbiztondo, A. Peralta, I. Pellejero, J. Sesé, M.P. Pina, I. Dufour, J. Santamaria. Sensors and Actuators B, 171-172 (2012) 822.

[5] A. Grave, J. Olsen, N. Privorotskaya, L.R. Senesac, T Thundat, W.P. King, A. Boisen, A. Microelectron. Eng. 87 (5-8) (2010) 696.

Figures

Figure 3: Resonant frequency changes per µg of zeolite BEA-Fe in presence of different concentration of toluene (13.5 mg/L- 3500 ppmV), water (2.1 mg/L- 2800 ppmV), and o-nitrotoluene (0.14 mg/L- 25 ppmV) at 30ºC and 55ºC.

Table 1: Detection results at 30ºC and 55ºC of 2-nitrotoluene, toluene and water by using zeolite HBEA and BEA-Fe. * Calculated from following fitting expression: Y = Yinf where Yinf represent the analyte adsorption per µg of zeolite in equilibrium and t1 is the time constant. ** Calculated from:

being R =

8,314 J·mol-1·K-1 and T1 and T2 expressed in K.

Figure 1: a) Chip with 8 microcantilevers (f0~72 KHz), and b) connection scheme of one microcantilever with electromagnetic actuation, piezo-resistive detection and integrated heater.

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Figure 2: Resonant frequency changes per µg of zeolite HBEA in presence of different concentration of toluene (13.5 mg/L- 3500 ppmV), water (2.1 mg/L- 2800 ppmV), and o-nitrotoluene (0.14 mg/L- 25 ppmV) at 30ºC and 55ºC.

Oral Plastics and Nanomaterials, new approaches for advanced properties

Luis Roca Blay

lroca@aimplas.es AIMPLAS Gustave Eiffel, 4 (València Parc Tecnològic) 46980 - PATERNA (Valencia), Spain

Carbon Nanotubes, Inorganic nanotubes, nanoclays, graphene; Nanomaterials offer a big potential for many properties: Electrical and thermal [1] conductivity, EMI [2] shielding, flame retardancy [3], antimicrobial activity, active principles release [4], or custom made materials due to nanomaterial’s modification; all these properties can be applied in many fields of high added value: Security, defense or health among others.

Nanomaterials by themselves can not fulfil the expectations of their good properties; they need a support, plastics, to be integrated for further transformation in useful items, plastic parts (protective cases, helmets, sockets etc…), plastic films, fibers (sensors [5] and high performance textiles).

Melt compounding is the technique that allows incorporating these new materials within plastics and dispersion is the key point, if we are not able to disperse properly these nanomaterials it will be impossible to reach these properties in the final products.

Plastics and its processing methods such as multilayer film die cast, co-injection or bi-injection moulding allow maximizing and economizing the efectivity of nanomaterials.

Therefore a holistic point of view of the challenge could give us the solution, nanomaterial plus plastic plus adequate processing method equals to desired performance.

[2]

[3]

[4]

[5]

Zhidong Han, Progress in Polymer ScienceVolume 36, Issue 7, July 2011.

“Comparative study of electromagnetic interference shielding properties of injection molded versus compression molded multiwalled carbon nanotube/polystyrene composites”, Mohammad Arjmand et al.

Carbon, Volume 50, Issue 14, November 2012.

“Nanoclay and carbon nanotubes as potential synergists of an organophosphorus flameretardant in poly(methyl methacrylate)”, Nihat Ali Isitman, Polymer Degradation and Stability, Volume 95, Issue 9, September 2010.

“Carbon nanotube nanoreservior for controlled release of anti-inflammatory dexamethasone” Xiliang Luo et al, Biomaterials, Volume 32, Issue 26, September 2011.

“Electromechanical performance of poly(vinylidene fluoride)/carbon nanotube composites for strain sensor applications”, A. Ferrreira et al, Sensors and Actuators A: Physical, Volume 178, May 2012.

References

578

[1] “Thermal conductivity of carbon nanotubes and their polymer nanocomposites: A review”,

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Oral Idoia Sancet

TECNAN S.L. Área Industrial “Perguita” , C/ A Nº1, 31210 Los Arcos , Navarra (Spain)

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Security and Defense.

Using TECNAN nanomaterials it is possible to improve different factors among this field: • Transparency: - TCOs: For specific pieces and coatings mainly in electronic devices.

- Transparent ceramics: To substitute glass elements in Night Vision devices or electromagnetic windows ‐ Improvement of abrasion resistance, strength and thermal stability.

Also they can be used As optical materials for specific lasers - New shields: To obtain transparency and provide maximum resistance without high weights.

• Magnetism: - Improved magnets: They make possible the miniaturisation and weight reduction of devices such as engines as well as the use of new weapons like the railgun.

- Magnetorheological fluids: For fast reinforcement of military cloth pieces or sudden transformation of temporary rigid structures. These fluids also improve the response in dampers which are subjected to extreme battle conditions.

• Merging into landscape (energy demand)/ Invisibility: - New energy storage devices like flux batteries by the use of new nanomaterials for highly active electrodes.

- Li‐ion batteries could be also improved with highly active nanomaterials - New complex nanomaterials are being developed to be deposited over solar panels so as to increase the quantity of visible light available for its transformation into electricity, taking advantage of additional radiations like IR and UV. • Visibility distortion: - Coating of nanocrystals: To distort normal light behavior over objects providing new possibilities

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TECNAN S.L. was created in December 2007 with the aim of producing and commercializing at industrial scale nanoparticles for multisectoral applications as well as other products based on them.

Currently, TECNAN counts with three lines of products: Powder Nanoparticles: TECNAN produces a wide range of ceramic nanopowders including simple and complex oxides, phosphates and carbonates.

Among the complex species which are available it is worth highlighting the mixed oxides which can be specifically synthesized according to the requirements of the client due to the outstanding versatility of the technology employed, being the only company in the world that has the capacity of producing at industrial scale these kind of nanoparticles.

The resulting nanoproducts have a high purity, low aggregation, narrow size distribution, very small size and a great specific surface area, what improves its activity and efficiency and makes those nanomaterials optimum for a big number of customized applications.

Nanodispersions: the nanoparticles produced by TECNAN can be supplied dispersed in a liquid media facilitating the introduction of these materials into the production processes and products of the clients.

READY TO USE PRODUCTS: nanoparticles‐based compositions ready to be directly applied on different substrates obtaining effects like hydrophobicity or oleophobicity.

TECNAN counts with an industrial capacity (tons per year) along the whole process having large‐scale production equipment based on advanced technologies.

The nanoproducts produced by TECNAN have different applications within the field of the

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Applications of TECNAN Nanoproducts in security and defense

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of refraction and reflection, both mirror and diffuse, as well as antireflective to avoid revealing the position of moving units with glass components.

• Material reinforcement (textiles): - High resistance textiles: Using nanomaterials or nanocomposites it is possible to improve resistance and supply textiles with properties like fire‐resistance or hydrophobicity.

• Missile deviation: - Modification of communication frequency: Using innovative geometric patterns combining conductive and isolating materials.

- New magnetically tunable filters and resonators for microwaves frequencies.

- Fake heat elements: An specific coating could be activated over specifically located objects/element so that a sudden exothermic reaction is produced.

Heat would be the result of a chain reaction where free radicals are involved.

• Others: - The ready to use products produced by TECNAN, could be applied for instance in security vehicles to improve the visibility of drivers or could be applied on facades of military buildings providing them with antigraffiti properties.

Figures

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Invited a

Claudia SimĂŁo 1 1 W. Khunsin , J. Gomis 2 T. Kehoe, D. Tuchapsky N. Kehagias1, A. Amann2 1,3,4 and C. M. Sotomayor Torres

1

Institut Català de Nanotecnologia, Edifici Nanotecnologia ICN2, Campus de la UAB. 08193 Barcelona, Spain; 2 School of Chemistry and the Tyndall National Institute, UCC, Cork Ireland; 3 Catalan Institute of Research and Advanced Studies (ICREA), Barcelona 08010, Spain; 4 Physics Department, Universitat Autònoma de Barcelona, Campus de la UAB, 08193 Bellaterra, Spain

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References [1] P.S. Peercy, Nature, 406 (2000) 1023-1026.

[2] W. Khunsin, A. Amann, G. Kocher-Oberlehner, S.G. Romanov, S. Pullteap, H.C. Seat, E.P. O'Reilly, R. Zentel, C.M. Sotomayor Torres, Adv. Funct. Mater., 22 (2012) 1812-1821.

[3] W. Khunsin, G. Kocher, S.G. Romanov, C.M. Sotomayor Torres, Adv. Funct. Mater., 18 (2008) 2471-2479.

[4] ] R.A. Farrell, N. Kehagias, M.T. Shaw, V. Reboud, M. Zelsmann, J.D. Holmes, C.M. Sotomayor Torres, M.A. Morris, ACS Nano, 5 (2011) 1073-1085.

[5] C. Simao, A. Francone, D. Borah, O. Lorret, M. Salaun, B. Kosmala, M.T. Shaw, B. Dittert, N. Kehagias, M. Zelsmann, M.A. Morris, C.M. Sotomayor. Torres, J. Photopolym. Sci. Technol., 25 (2012) 239-244.

[6] C.M. Sotomayor Torres, Alternative Lithography: Unleashing the Potentials of Nanotechnology, Springer, 2003.

[7] S. Zankovych, T. Hoffmann, J. Seekamp, J.U. Bruch, C.M. Sotomayor Torres, Nanotechnol., 12 (2001) 9195.

Figures

Figure 1: Opposite partner method for order quantification of selfassembled opals (a) and block copolymers (b).

Figure 2: Solvent assisted nanoimprint lithography (SAIL) process workflow (a) and SEM image of a poly(styrene-b-ethylene oxide) thin film imprinted by SAIL.

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Civilization progress has settled on the invention of novel devices and machines that improved greatly our daily life. In the last century, a great variety of novel instruments used for collecting, processing, displaying and storing information have come into use. Particularly, the vertiginous progress around information technology has been closely related to the progressive miniaturisation of the components employed for the construction of such devices and machines. [1] Dimensions get smaller and smaller reaching down to the atomic scale. The density of devices is still destined to increase in the future and to become reality, nanotechnology has to overcome continuously its limitations. While welldefined metrology down to the micrometer scale, the nanometre scale is largely unexplored in the context of dimensional metrology solutions suitable for transfer to the manufacturing environment.

Dimensional and positional metrology can play a major role in reproducibility, quality control, setting up standards but much more: positional metrology of nanostructures can potentially be used to enforce legislation on trademark and production of high-value or high-tec manufactured parts and products.

In this talk I will address two powerful approaches to dimensional and positional nanometrology, namely sub wavelength diffraction and the opposite element approach. [2, 3] The method will be illustrated in the few tenths of nm regime in the self-assembly of diblock copolymers. Our work devises sub-20 nm features on surfaces using block copolymers as alternative lithographic masks,[4, 5] by making use of nanoimprint lithography (NIL) technique.[6, 7]

claudia.simao@icn.cat

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Dimension and positional metrology approaches in nanotechnology

Invited Detection of Neurotoxic Gases by Functionalized Silicon Nanowire FieldEffect Transistors

1

Jean-Pierre Simonato 1 1 L. Ordronneau A. Carella 2 2 V. Passi , E. Dubois S. Lenfant2 and 2 D. Vuillaume jean-pierre.simonato@cea.fr

1

CEA-Liten, 17 rue des Martyrs, 38054 Grenoble, France 2 IEMN-CNRS, Avenue PoincarĂŠ, 59652, Villeneuve d'Ascq, France

The threat of a chemical attack on homeland and military forces continues to grow and recent examples such as the terrorist attack of the Metro of Tokyo have clearly shown that organophosphorus agents (OPs) are powerful neurotoxic molecules that can actually be used as weapons of chemical terrorism.

Some sensors are commercially available to detect warfare gases; however they suffer from some intrinsic defects that reduce significantly their interest in some specific kinds of operation. Up to now, there is still a lack of supersensitive and specific autonomous tiny sensors.

New sensors based on one-dimensional semiconducting nanomaterials like silicon nanowires have been chemically functionalized with tailor-made molecules for detection of traces of toxic gases. In particular, a chemical receptor specific to traces of neurotoxic OPs like Sarin has been synthesized and grafted to sensitive nanomaterial based electrical devices.

These results show that it is possible to detect very efficiently sub-ppm traces of OPs with high selectivity by monitoring the Drain-Source current of the SiNW-FET at an optimum back gate voltage as a function of time.

We will present results starting at the nanoscale using functionalized nanomaterials, up to their integration in an autonomous demonstrator.[1-5]

[3] Passi V., et al., IEEE Electron Device Letters, 32 (2011) 976.

[4] Clavaguera S., et al., Talanta, 85 (2011) 5242.

[5] Patents to CEA.

Figures

References

582

[1] Clavaguera S., et al., Angewandte Chemie Int. Ed., 49 (2010) 4063.

[2] Delalande M., et al., Chemical Communication, 47 (2011) 6048.

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INDUSTRIAL FORUM

2013

Index Industrial Forum Contributions Invited

Pag

■ Fréderic Amblard (CEA, France) -

Abstrat not provided by the speaker

■ Sven Bauerdick (Raith GmbH, Germany) "Advanced Focused Ion Beam Lithography for photonic, nanobio and graphene applications"

594

■ Jaques Bouillard (National Institut of Environmental and Industrial Risk, France) -

"Environmental risk. Aspects in nanosafety” (Abstrat not provided by the speaker)

■ Emmanuel Brun (European Agency For Safety And Hearth At Work, Belgium) -

"Nanomaterials and safety and health at work: an overview" (Abstrat not provided by the speaker)

■ Steffi Freidrichs (NIA, Belgium) "Advances on nanotechnology: From regulatory and safety-issues to commercialization and environmental and societal benefits" (Abstrat not provided by the speaker)

-

■ Jean-Charles Guibert (MINATEC, France) -

"Abstrat not provided by the speaker

■ Stéphanie Lacour (CECOJI-UMR 6224, Francia) "Interdisciplinar building of Nanosciences and nanotechnologies policies"

603

■ Amaia Martinez Muro (Agencia NanoBasque, Spain) "nanoBasque Strategy: Basque Country´s BIG commitment to the very small"

604

■ Michael Silver (American Elements, USA) "Recent Research & Development at American Elements Using Nanotechnology in Fuel Cells"

Oral

613

Pag

■ Timothy Ashworth (NanoScan AG, Switzerland) "A versatile, fully-integrated dual PLL controller for SPM with application to magnetic force microscopy"

593

■ Félix Bayón (GERDAU, Spain) "Contribution of micro/nanotechnologies in off-shore wind energy"(Abstrat not provided by the speaker)

-

■ Anthony Bochon (Université libre de Bruxelles (ULB), Belgium)) "Patenting and licensing nanotechnologies in Europe: now and the future"

596

■ Montserrat Calleja (Progenika-Mecwins, Spain) "BIOMEMS Micro and nano electromechanical systems for the life sciences" (Abstrat not provided by the speaker)

-

■ Maria Chachamidou (Aristotle Univ. of Tessaloniki, Greece) "Commercialisation of Organic and Large Area Electronics – COLAE Project"

598

■ Jose María Cuevas (GAIKER-IK4, Spain)

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600

585

"Successful cases of technological transfer from IK4 Research Alliance"

Oral

Pag

■ Begoña Galindo (AIMPLAS, Spain) "European Project NanoMaster Develops Graphene-based Thermoplastic Masterbatches for Conventional & Additive Manufacturing Processes"

602

■ Nuria Gisbert (CIC microGUNE, Spain) "The way to commercialization of Micro-Bio-Nano Systems. MNBS Cluster & EpoSS" (Abstrat not provided by the speaker)

-

■ José Ignacio Hormaeche(Basque Energy Cluster, Spain) "Technological needs and challenges of off-shore wind energy" (Abstrat not provided by the speaker)

-

■ Pedro Ilundain (Ikerlat Polymers, Spain) -

"Personalized Latex Particles"(Abstrat not provided by the speaker)

■ Arrate Jaureguibeitia (Biolan, Spain) "Biosensors applied to agro-food industry as a fast, effective and economical method to ensure quality and safety of products" (Abstrat not provided by the speaker)

-

■ Jean Baptiste Jorcin (Tecnalia) "Contribution of micro/nanotechnologies in off-shore wind energy"(Abstrat not provided by the speaker)

-

■ Iban Larroulet (Sensia, Spain) -

"...from the Idea to the Product..." (Abstrat not provided by the speaker)

■ Maria José López (Interplataforms Nanosafety Group, Spain) "Interplatforms Initiative about nanosafety" (Abstrat not provided by the speaker)

-

■ Javier Marqués (EVE) "Technological needs and challenges of wave power" (Abstrat not provided by the speaker)

-

■ Sébastien Maussang (Renishaw, Spain) "Recent advances in fast imaging Raman technology for nano materials characterisation"

605

■ Kepa Mayora ((CIC microGUNE, Spain) "The way to commercialization of Micro-Bio-Nano Systems. MNBS Cluster & EpoSS" (Abstrat not provided by the speaker)

-

■ Kazuo Muramatsu (Incubation Alliance, Japan) 606

"Mass production of high quality Graphene"

■ Mario Ordoñez (MAIER Group) -

"Nanotehcnology at Maier Group" (Abstrat not provided by the speaker)

■ Cristina Oyón (nanoBasque Agency - SPRI, Spain) "Introduction and methodology in the creation of a Road Map to apply micro/nanotechnologies in Marine Energies" (Abstrat not provided by the speaker)

-

■ Antonio Porro (Tecnalia, Spain) 608

"Nanotechnology, from technology push to market pull"

■ Fernando Resina (Vieira de Almeida & Associados, Portugal) 609

"Models for investment in R&D and Technology Transfer in Nanotechnology"

■ Sofia Rodriguez (Nanoscribe GmbH, Germany) "High-speed 3D laser lithography with high NA-objectives for 3D micro and nanofabrication"

611

■ Ainara Rodríguez (CIC microGUNE)

586

"Contribution of micro/nanotechnologies in off-shore wind energy" (Abstrat not provided by the speaker)

-

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Oral

Pag

■ Iñaki Sadaba (Iline Microsystems, Spain) "Point-of-Care Diagnostics in Haemostasis" (Abstrat not provided by the speaker)

-

■ Vasco Teixeira (Minho University, Portugal)

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614

587

"The strategic investment in a Europe of Knowledge and Innovation: challenges for the new Framework Programme Horizon 2020"

Index Graphene2013 Contributions Alphabetical Order I:Invited / O: Oral

Pag

■ Fréderic Amblard (CEA, France) Abstrat not provided by the speaker

I

-

O

593

I

594

O

-

O

596

I

-

I

-

O

-

O

598

O

600

I

-

O

602

O

-

I

-

O

-

O

-

O

-

■ Timothy Ashworth (NanoScan AG, Switzerland) "A versatile, fully-integrated dual PLL controller for SPM with application to magnetic force microscopy"

■ Sven Bauerdick (Raith GmbH, Germany) "Advanced Focused Ion Beam Lithography for photonic, nanobio and graphene applications"

■ Félix Bayón (GERDAU, Spain) "Contribution of micro/nanotechnologies in off-shore wind energy"(Abstrat not provided by the speaker)

■ Anthony Bochon (Université libre de Bruxelles (ULB), Belgium) "Patenting and licensing nanotechnologies in Europe: now and the future"

■ Jaques Bouillard (National Institut of Environmental and Industrial Risk, France) "Environmental risk. Aspects in nanosafety” (Abstrat not provided by the speaker)

■ Emmanuel Brun (European Agency For Safety And Hearth At Work, Belgium) "Nanomaterials and safety and health at work: an overview" (Abstrat not provided by the speaker)

■ Montserrat Calleja (Progenika-Mecwins, Spain) "BIOMEMS Micro and nano electromechanical systems for the life sciences" (Abstrat not provided by the speaker)

■ Maria Chachamidou (Aristotle Univ. of Tessaloniki, Greece) "Commercialisation of Organic and Large Area Electronics – COLAE Project"

■ Jose María Cuevas (GAIKER-IK4, Spain) "Successful cases of technological transfer from IK4 Research Alliance"

■ Steffi Freidrichs (NIA, Belgium) "Advances on nanotechnology: From regulatory and safety-issues to commercialization and environmental and societal benefits" (Abstrat not provided by the speaker)

■ Begoña Galindo (AIMPLAS, Spain) "European Project NanoMaster Develops Graphene-based Thermoplastic Masterbatches for Conventional & Additive Manufacturing Processes"

■ Nuria Gisbert (CIC microGUNE, Spain) "The way to commercialization of Micro-Bio-Nano Systems. MNBS Cluster & EpoSS" (Abstrat not provided by the speaker)

■ Jean-Charles Guibert (MINATEC, France) Abstrat not provided by the speaker

■ José Ignacio Hormaeche(Basque Energy Cluster, Spain) "Technological needs and challenges of off-shore wind energy" (Abstrat not provided by the speaker)

■ Pedro Ilundain (Ikerlat Polymers, Spain) "Personalized Latex Particles"(Abstrat not provided by the speaker)

■ Arrate Jaureguibeitia (Biolan, Spain)

588

"Biosensors applied to agro-food industry as a fast, effective and economical method to ensure quality

ImagineNano2013

I:Invited / O: Oral

Pag

and safety of products" (Abstrat not provided by the speaker)

■ Jean Baptiste Jorcin (Tecnalia) "Contribution of micro/nanotechnologies in off-shore wind energy"(Abstrat not provided by the speaker)

O

-

I

603

O

-

O

-

O

-

I

604

O

605

O

-

O

606

O

-

O

-

O

608

O

609

O

611

O

-

O

-

I

613

O

614

■ Stéphanie Lacour (CECOJI-UMR 6224, Francia) "Interdisciplinar building of Nanosciences and nanotechnologies policies"

■ Iban Larroulet (Sensia, Spain) "...from the Idea to the Product..." (Abstrat not provided by the speaker)

■ Maria José López (Interplataforms Nanosafety Group, Spain) "Interplatforms Initiative about nanosafety" (Abstrat not provided by the speaker)

■ Javier Marqués (EVE) "Technological needs and challenges of wave power" (Abstrat not provided by the speaker)

■ Amaia Martinez Muro (Agencia NanoBasque, Spain) "nanoBasque Strategy: Basque Country´s BIG commitment to the very small"

■ Sébastien Maussang (Renishaw, Spain) "Recent advances in fast imaging Raman technology for nano materials characterisation"

■ Kepa Mayora ((CIC microGUNE, Spain) "The way to commercialization of Micro-Bio-Nano Systems. MNBS Cluster & EpoSS" (Abstrat not provided by the speaker)

■ Kazuo Muramatsu (Incubation Alliance, Japan) "Mass production of high quality Graphene"

■ Mario Ordoñez (MAIER Group) "Nanotehcnology at Maier Group" (Abstrat not provided by the speaker)

■ Cristina Oyón (nanoBasque Agency - SPRI, Spain) "Introduction and methodology in the creation of a Road Map to apply micro/nanotechnologies in Marine Energies" (Abstrat not provided by the speaker)

■ Antonio Porro (Tecnalia, Spain) "Nanotechnology, from technology push to market pull"

■ Fernando Resina (Vieira de Almeida & Associados, Portugal) "Models for investment in R&D and Technology Transfer in Nanotechnology"

■ Sofia Rodriguez (Nanoscribe GmbH, Germany) "High-speed 3D laser lithography with high NA-objectives for 3D micro and nanofabrication"

■ Ainara Rodríguez (CIC microGUNE) "Contribution of micro/nanotechnologies in off-shore wind energy" (Abstrat not provided by the speaker)

■ Iñaki Sadaba (Iline Microsystems, Spain) "Point-of-Care Diagnostics in Haemostasis" (Abstrat not provided by the speaker)

■ Michael Silver (American Elements, USA) "Recent Research & Development at American Elements Using Nanotechnology in Fuel Cells"

■ Vasco Teixeira (Minho University, Portugal)

ImagineNano2013

589

"The strategic investment in a Europe of Knowledge and Innovation: challenges for the new Framework Programme Horizon 2020"

A b s t r ac t s Alphabetical order

INDUSTRIAL FORUM 2013

Oral A versatile, fully-integrated dual PLL controller for SPM with application to magnetic force microscopy

1

Timothy V. Ashworth 1 R. Dianoux 1 A. Scheidemann S. Zürcher1, H. Hosny1 2 2 M. Krehl and T. Heller

tv.ashworth@nanoscan.ch NanoScan AG, Überlandstrasse 129, 8600 Dübendorf, Switzerland ION-TOF GmbH, Heisenbergstrasse 15, 48149 Münster, Germany

A fully integrated Scanning Probe Microscope (SPM) controller featuring single and dual phase locked loops (PLL) has been developed by NanoScan. Here, its outstanding properties are briefly illustrated by application examples from our range of high and ultra-high vacuum SPM’s.

This modular SPM controller features all the necessary components to control a vacuum SPM. All standard SPM modes are available: from STM to non-contact AFM, and also Kelvin probe force microscopy.

The controller is matched to drive both tubescanners and fully-linearized flexure stages. The High Voltage Amplifier is specifically designed for the needs of the tube-scanner user, with ethernet controllable gains up to ±400V, attenuations and offsets enabling the use of the full range of controller output in an image size which can be arbitrarily small.

The Piezo-Motor Controller can combine fast sample stage drive with 20-nm accuracy positioning. This feature is taken advantage of with the unique Point-Approach Mode to record topographical data over long distances.

Both interferometric and optical beam deflection for cantilever oscillation detection are supported by the controller. Stand-alone hardware components are available: either a homodyne interferometer with adjustable outputs, or a fourquadrant beam deflection detection electronics.

To demonstrate the flexibility of the controller, a case study is presented where the controller is running a low temperature magnetic force microscope in a variable magnetic field. The sample studied is an example of the so-called bitpatterned media (BPM). BPM is one potential candidate to replace the current continuous

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magnetic recording media once the limit of bit density has been reached.

Bit-patterned media consists of magnetic islands which are physically discrete from one another.

This allows more magnetic bits to be packed into the same area. Physically structuring the media leads to many challenges, one of which is the wide switching field distribution (SFD) of the array of islands. Ideally, the SFD would be zero, and all islands would flip their magnetisation at the same field. In practise, there are many parameters which lead to an imperfect SFD such as morphology and strain.

This study investigates the SFD of BPM with island size 50 nm using magnetic force microscopy in an applied magnetic field. An array of islands was imaged and the SFD determined from the series of MFM images taken in increasing magnetic field.

Carrying out the same series of in-field MFM measurements at room temperature, low (10K) and elevated (360K) temperatures, the temperature dependence of the SFD, along with the coercivity of the islands can be elucidated.

Both the SFD and the coercivity increase with increasing temperature.

The same array was subsequently imaged in noncontact mode with a non-magnetic tip to elucidate the size and local morphology of the islands.

INDUSTRIAL FORUM

2

593

1

Invited Advanced Focused Ion Beam Lithography for photonic, nanobio and graphene applications

Sven Bauerdick A. Nadzeyka and A. Remscheid

bauerdick@raith.de

Raith GmbH, Konrad-Adenauer-Allee 8, 44263 Dortmund, Germany

594

Focused ion beam (FIB) systems and combined FIBSEM microscopes are widely used for sample preparation and various analytical tasks.

Moreover, focused Ion Beam Lithography (IBL) can have significant advantages over electron beam lithography (EBL), like direct, resistless, and threedimensional patterning, while at the same time delivering the in-situ process control by crosssectioning and inspection that a FIB instrument typically affords. A dedicated IBL tool will overcome nanofabrication specific limitations of an analytical platform by employing true lithography architecture and an ion column and source optimized for high resolution and large area nano patterning. This includes in particular a laser interferometer stage, long-term beam to sample position stability, as well as enhanced beam current stability and true automation capabilities.

These system features enable high resolution, large area patterning over long times for IBL applications such as X-ray zone plates [1], various photonic and plasmonic structures, large area gratings [2], and wafer-level nanopore devices (see Figure 1). As a result IBL is as powerful as, complementary to, and compatible with (mix & match) the other lithography techniques commonly found in nanoscale research and development facilities.

Membrane based solid state nanopore devices for DNA sequencing, molecule analysis or biological filtering are both from a scientific and an increasingly commercial point of view a high interest topic [3,4].Desirable nanopores must be <20 nm to permit single molecule transit, they must be round, have high aspect ratio, and minimal damage or implantation of contaminants around them. A large number of nanopore devices are spent for research and in particular for

commercial screening applications, which requires small batch wafer scale production with additional stability and reproducibility constrains on the process and instrumentation.

We have automatically fabricated 20 nm pores in 100 nm thick Si3N4 membranes on a 4 inch wafer (see Figure 1). In particular the reproducibility has been investigated by wafer-scale scanning electron microscope metrology capabilities of an EBL system.

Graphene synthesis, fabrication and patterning have been approached with various techniques, whereas the focused ion beam has been used for direct milling of suspended flakes [5]. Moreover we have developed a novel graphene nanoribbon nanofabrication process [6] employing specific ion implantation for reducing the graphitization temperature of SiC bulk substrates (see Figure 2).

We will report on these and other applications showing the benefits of ion beam patterning and especially the added capabilities of IBL. Results of sub 10 nm feature sizes, on highly topographic samples, of three-dimensional structures and of long-term processes are presented.

References [1] A. Nadzeyka et al., Microelectronic Engineering 98 (2012), 198-201.

[2] S. K. Tripathi et al., J. Micromech. Microeng.

22 (2012), 055005.

[3] J. Edel, T. Albrecht, Nanopores for Bioanalytical Applications: Proceedings of the First International Conference (ROYAL SOC OF CHEMISTRY, 2012).

[4] B. Schiedt et al., Microelectronic Engineering 87 (2010), 1300.

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[5] ] J. Gierak et al., MRS Proceedings 1259 (2010), 47.

[6] S. Tongay et al., Appl. Phys. Lett. 100 (2012), 073501.

Figures

Figure 1: Reproducible fabrication of nanobio devices with nanometer precision at wafer-scale.

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Figure 2: Novel fabrication process for graphene nanoribbons.

Oral Patenting and licensing nanotechnologies in Europe: now and the future

Anthony Bochon

abochon@ulb.ac.be

Université libre de Bruxelles (ULB) Avenue Franklin Roosevelt 50, CP 180; 1050 Brussels, Belgium

596

Although some skeptical lawyers still think that nanotechnologies do not change law substantially, patent law is a perfect example of the hot areas where researchers and industrials face the most difficult legal challenges. Patent Law texts applicable in Europe have been drafted at times where scientific knowledge was not comparable with the evolution seen during the last 20 years.

The conference will cover four different topics: the patentability of nanotechnologies, the future of the directive on the patentability of biotechnological inventions, the perspectives offered by the new unitary patent system and the future New regulation on licensing agreements on the transfer of technology which will be adopted in late 2013.

Patenting nanotechnologies At the level of the European Patent Convention, the different conditions of patentibility are questionnable. Although the case law of the European Patent Office remains limited, some trends about issues can already be pointed out of the recent cases delivered by the Board of Appeal.

The national case law also highlights hurdles that may appear.

Among the conditions, novelty and the question of the state of the art are challenged by certain nanotechnologies. The patent claims are sometimes subject to examination failures when applications seek patent recognition on unclearly limited nanotechnologies.

Nanotechnologies represent an opportunity of using utility models again as they are very popular in China and enhance the competitiveness of companies.

The future of the directive on the patentability of biotechnological inventions None can speak about nanotechnologies without drawing some parallelism with the most common

precedent to which nanotechnologies are compared, i.e. biotechnologies whose increasing R&D activities and business shaped many debates and legal changes in the 90s.

The current approach of the European Union towards nanotechnologies differs from the way it dealt with biotechnologies more than 10 years ago. The European Union’s answer to biotechnologies resulted in the adoption of various autonomous legal instruments while the Union prefers now to adapt the existing legal framework to integrate nanotechnologies.

In the field of intellectual property, the 98/44/EC directive provided for several years an answer to patenting issues in an emerging scientific field.

Nanobiotechnologies fall today in its scope and we may ask seriously whether the directive is not outdated or not.

A careful analysis of the provisions of the directive in the light of the case law of the European Court of Justice will allow to draw some conclusions about a potential call for review of this directive, as it concerns a substantial part of nanotechnological patents.

The new unitary patent sytem Second to last, the future impact of the unitary patent system adopted in December 2012 will be assessed.

This unitary patent system offers an alternative to the classical route that applicants follow with the so-called « European patent ». Although this system does not have any nanotechnology-related aspect, it will certainly improve the competitiveness of many actors of the industry as it decreases the costs for patenting inventions.

The future new Regulation on Licensing Agreements on the Transfer of Technology Finally, the conference will highlight the changes that will be brought by the new Regulation

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Technology Transfer Block Exemption to be adopted in mid-2013.

The current difficulties raised by market definitions will be pointed out, as well as the impact of a potential consumer choice that will, in the near future, distinguish markets for nano-free products and products including nanotechnologies.

Oral Commercialisation of Organic and Large Area Electronics – COLAE Project

Maria Chachamidou S. Logothetidis

mchacham@auth.gr logot@auth.gr Aristotle University of Thessaloniki, Department of Physics, Lab for Thin Films- Nanosystems & Nanometrology (LTFN), GR-54124 Thessaloniki, Greece

598

The area of Organic and Large-area Electronics (OLAE) is a new scientific and technological field of Nanotechnology with a multitude of potential applications that offer substantial advantages and the possibility for low cost large-scale manufacturing processes in high volumes. Most new technical and business opportunities are perceived to be in energy (Organic PhotovoltaicsOPV), displays (Organic Light Emitting DiodesOLEDs), lighting, signage, sensors (Organic Thin Film Transistor- OTFT), smart labeling and medicine (Organic Biosensors) [1, 2]. The applications of Organic Electronics are already penetrating every commercial and industrial field, aiming to dominate every aspect of life worldwide [3]. Europe has been pulling ahead of the rest of the world in many aspects of OLAE and probably has the most robust vertical integration of effort in OLAE. Actors in OLAE field in Europe involve several big companies, corporate and academic spin-offs [4], start ups as well as Universities and Research Institutes across various European countries that have contributed greatly to the growth of what is widely recognized to be a commercial prospect with immense potential [5].

Since OLAE technologies are becoming ready for incorporation into products of all types there is a need for technology transfer and research commercialization.

Europe’s leading organizations are collaborating to form COLAE – Commercialization of Organic and Large Area Electronics – a European funded project under the Seventh Framework Programme [6]. The project is designed to promote the commercial exploitation of OLAE technology for the benefit of European industry. COLAE aims to provide to European companies effective access to the knowledge base and technology know-how of

key European OLAE partners and their regional OLAE clusters, high-quality training, OLAE product and business idea feasibility support, the best European manufacturing, pilot production facilities and services, important future research topics through workshops, advanced OLAE open innovation process and coordinated support for better IPR landscaping and exploitation.

The expected impacts of COLAE include the growth of OLAE R&D services in Europe, increased effective product demonstration and pilot services, the improved coordination of infrastructure investments, the enlargement of the network of OLAE companies and an increase in the number and capability of OLAE technologists and designers. To achieve this, project activities include awareness of the opportunities given by OLAE. COLAE provides evaluation and verification of opportunities and provides a coordinated support service for their needs. A program of training, providing basic awareness as well as more advanced technology and entrepreneurship courses is being implemented. An OLAE feasibility network is being established and verified by executing selected trial cases in which new users of OLAE will be assisted to examine the feasibility of using OLAE technology into applications. The OLAE feasibility network is an important step towards the concept of a virtual European OLAE foundry, together with the development of an open innovation model for collaboration and rapid commercialization of OLAE.

References [1] Strategic Research Agenda Organic & Large Area Electronics (2009).

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[2] Logothetidis S., Materials Science and Engineering: B, Volume 152, Issues 1â&#x20AC;&#x201C;3, 25, Flexible organic electronic devices: Materials, process and applications (2008), 96-104.

[3] Intertechpira. Printed, Organic & Flexible Electronics Forecasts, Players & Opportunities 2012-2022, http://www.idtechex.com (2012).

[4] Chachamidou, M. & Logothetidis, S., Proceedings of the 2nd International Symposium on Flexible Organic Electronics, Academic entrepreneurship: the case of organic electronics (2009).

[5] Organic Electronics Association (OE-A), Roadmap for Organic and Printed Electronics (2011).

[6] COLAE Project- Commercialization of Organic and Large Area Electronics http://www.colae.eu (2012).

Oral Successful cases of technological transfer from IK4 Research Alliance

1 2

GAIKER-IK4, Parque Tecnológico, Edificio 202, 48170 Zamudio, SPAIN, IK4-TEKNIKER, Iñaki Goenaga 5, 20600 Eibar, Spain

600

IK4 Research Alliance comprises nine technological centers and is one of the major points of reference. Our main objective is to bring resources together and to exchange best practice in order to help our technological centers reach greater levels of technological-scientific excellence within the Basque System of Innovation. The following technology centers form part of IK4: AZTERLAN, CEIT, GAIKER, IKERLAN, LORTEK, TEKNIKER, CIDETEC, IDEKO and VICOMTech. As a result of our work, some results lead to the generation of patents, new products or spin-off companies. Two successful cases will be explained.

1/ The improvement in fatigue and wear resistance under high pressures in mechanical components is currently more and more taken into account as possible way of diminishing their component weight in association with a cost diminution. This is very important in industrial sectors under pressure like the automotive industry.

Traditionally DLC (Diamond like Carbon) layers have been studied and proposed for these tribological applications. These DLC thin layers have already shown some weak points for high temperature applications since the DLC layers tend to graphitize above 180ºC producing the failure of the tribo-systems. Thus, an alternative Zr(C,N) coating has been developed by IK4-TEKNIKER. Cathodic arc evaporation was used to deposit this 2.5 micron coating on a nitrogen alloyed steel substrate (Cronidur 30). The carbon content of the coating (acetylene gas in the chamber) was a parameter of great importance in the tribological performance of the system. The interface should also remain clean in the first phase of the deposition and the process-related interlayer (here made in Zr) must be very thin to reduce the risk of contamination or defect presences (see Figure 1).

Jose María Cuevas 1 JR Alonso and 2 J Barriga

1

cuevas@gaiker.es alonso@gaiker.es javier.barriga@tekniker.es

The coating is crystalline with a cubic structure.

The evaluated average grain size is situated between 7 to 10 nm. A benchmarking carried out by the BMW [1], regarding the load carrying capacity and lifetime under lubricated rolling and slip-rolling motion of these novel coatings, has revealed that these layers resist mean Hertzian pressures of P0max >2.94 GPa under mixing/boundary friction conditions at oil temperature of over 100ºC and up to ten millions cycles. These results confirm that the developed Zr(C, N) coating outperformed the latest developments in DLC coatings under these working conditions, opening a new field of applications for zirconium based coatings.

2/ Graphene is formed by a crystalline hexagonal net of carbon atoms, forming a layer with a thickness of one only atom. Thus, it is a bidimensional material. This particular structure leads this material to present exceptional properties and a wide range of potential applications: electronics, batteries, touch-screens, automotive body parts, etc.

In this work, graphene oxide GRAnPH® is obtained from carbon nanofibers (GANF®) synthesized by the company Grupo Antolín using chemical methods.

Samples have been analyzed by transmission electron microscopy (TEM). The equipment is a Tecnai G2 S-TWIN (FEI company). Samples were previously prepared at Grupo Antolín laboratories and analyzed at GAIKER-IK4 by HRTEM with 200 kV of voltage.

From the images obtained by TEM we can see graphene films which thicknesses are likely to be bellow 1 nm. Besides, this tool allow us to see the layered structure, dimensions in XY directions and flexibility (see Figure 2, right). Finally, we can also know the efficiency of the method used to obtain

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graphene oxide. We have to observe the existence or absence of original carbon nanofibers and as a result we can adjust the process parameters

References [1] Charles-Alix Manier, Holger Ziegele, Javier Barriga, Josu Goikoetxea, Mathias Woydt, Zirconium-based coatings in highly stressed rolling contacts as alternative solution to DLC and ta-C coatings, Wear 269 (2010) 770–781.

Figures

Figure 1: GDOES profile showing the composition of Zr(C, N) coating.

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Figure 2: images of oxide GRAnPH® with and without carbon nanofibers GANF®.

Oral European Project NanoMaster Develops Graphene-based Thermoplastic Masterbatches for Conventional & Additive Manufacturing Processes

Begoña Galindo Galiana

bgalindo@aimplas.es

AIMPLAS València Parc Tecnològic C/ Gustave Eiffel, 4; 46980 PATERNA Valencia

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Graphene-based composites manufactured on a lab scale have been shown to exhibit impressive properties over unreinforced polymers. A small percentage of graphene within a polymer matrix can significantly improve its strength and stiffness, however the material remains prohibitively expensive for large-scale use as a composite reinforcement.Therefore, the concept for this project is to develop the knowledge-based processing methods required to up-scale the production of graphene and expanded graphite reinforced thermoplastic masterbatches and compounds and, ultimately, enable its industrial commercialisation in Europe. The work will focus on developing processes for large scale rapid production of graphene reinforced plastic intermediate materials which can be integrated into current conventional and additive manufacturing processes.

The project is led by NetComposites, UK, and involves 12 other project partners: Philips Consumer Lifestyle, Holland, Timcal, Switzerland, Röchling Automotive, Italy, Asociación de Investigación de MaterialesPlásticos y Conexas (AIMPLAS), Spain, Aero Engine Controls, UK, Teknologisk Institut, Denmark, Promolding, Holland, Avanzare InnovacionTecnologica, Spain, Master Build Prototype, France, The Institute of Occupational Medicine, UK, Create It Real Aps, Denmark, and LATI Industria Termoplastici, Italy.

NanoMaster commenced in December, 2011, and has recently produced new grades of expanded graphite and nano-graphite. These are designed to be easier to exfoliate in both chemical and mechanical processes and are also useful when trying to tailor the properties of the final composite for different applications.

Further to this, the project has now used the new grade of graphite (plus other commercial grades) to produce graphene via a multiple-stage chemical exfoliation process involving oxidative treatment, washing, filtration and reduction. The target is to produce graphene of tailored flake diameter. The process is able to produce these materials at high yield in short reaction times (up to 90% yield in <24 hours).

The next steps for the partners include; scaling up the direct graphene production techniques, developing graphene functionalisation techniques and to begin production of graphene-reinforced powder and rods for use in SLS and FDM, respectively. In addition, because information regarding the potential hazards and exposure routes for nanomaterials is extremely limited, NanoMaster will combine up-to-date surveys of exposure and hazard literature with a workplace questionnaire to give a comprehensive overview of the current status.

The research leading to these results has received funding from the European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement n° 285718.

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Invited Interdisciplinar building of Nanosciences and nanotechnologies policies

Stéphanie Lacour

stephanie.lacour@cnrs.fr

CNRS - Centre d’Etudes pour la Coopération Juridique Internationale (CECOJI) Ivry sur Seine – France

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References

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[1] [Kelty, 2009] Christopher M. Kelty, “Beyond Implications and Applications: the Story of ‘Safety by Design’”, Nanoethics, (2009), 3, pp.79–96.

[2] [Lacour and al., 2013] Stéphanie Lacour, Sacha Loeve, Brice Laurent, Virginie Albe, Aurélie Delemarle, Bernard BArtenlian and Sophie Lanone, “Deliberating Responsibility : a collective contribution by the C’Nano Ile de France Nanoscience &Society Office”, forthcoming in Foundation of Chemistry, 2013.

[3] [Cutcliffe and al., 2012] Stephen H. Cutcliffe, Christine M. Pense and Michael Zvalaren, “Framing the discussion: nanotechnology and the social construction of technology – What STS scholars are saying, Nanoethics (2012), 6, pp. 81-99.

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Since its beginning and the US National Nanotechnology Initiative launch in 2001, the development of nanosciences and nanotechnologies policies was accompanied by a strong incentive of responsibility. Scientists and policy makers were particularly urged to build the frame of this responsible development through the involvement of some concrete interdisciplinary collaborations with toxicologists and ecotoxicologists, but also human and social scientists.

When they occurred, these collaborations were fruitful. Toxicologists began to cooperate with those who could help them in the characterization of their samples and to frame the study of a wide variety of new and mostly unknown materials.

Human and social scientists learnt a lot about the nanoscience’s community rules and milestones, the nano-research reality and tools and were able built their own studies on these concrete data.

Nanoscientists also benefited from this new path, building on these collaborations to foster some new interdisciplinary research activities, including the “safety by design” approach [Kelty 2009].

The talk will relate the experience we gathered in the Region Ile de France, through the launching and work of the Centre of competences in nanosciences and its “Nanoscience and Society” transverse action, which supports academic works on the way nanoresearches and society are both influencing each other. By escaping disciplinary divides to think nanosciences and nanotechnologies together, we hope to give the discussions on nanotechnology’s development a better frame [Lacour and al. 2013] and to foster an original way to explore the social construction of science and technology [Cutcliffe and al., 2012].

Invited nanoBasque Strategy: Basque Country´s BIG commitment to the very small

Amaia Martínez Muro

nanobasque@spri.es nanoBasque Agency - SPRI, Paseo Mikeletegi 56, 20009 Donostia-San Sebastian, Spain

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The commitment of the Basque Government’s Department of Industry, Innovation, Trade and Tourism to nanoscience, micro and nanotechnology s a means of diversifying the industrial framework became clear several years ago and was confirmed with the official launch of the nanoBasque Strategy and the creation of an agency, namely the nanoBasque Agency at Spri, dedicated specifically to the roll-out of this strategy.

The incorporation of nanoscience, micro and nanotechnology as a strategic area for industrial diversification in terms of the Basque Country’s science, technology and innovation policies was undertaken with two main goals: to exploit the huge potential applications of these technologies in almost every industrial sector in the Basque Country, especially the car industry, aeronautics, energy, electronics, telecommunications, machinery/tools, steel, metallurgy and household appliances, and to promote the creation of new technology companies with the express purpose of taking full advantage of applications based on such technologies.

The first roll-out phase of this strategy involved laying its foundations with a significant public investment in knowledge generation, basically by creation of the cooperative research centres CIC microGUNE and CIC nanoGUNE. The increasingly important participation of companies together with science/technology agents in R+D projects in these fields, the launch of a support system for the development of new business projects, with the creation of a nanoincubator, and the recently launched initiative, EHS Advance, the Competence Centre for Environment, Health and Safety issues that will support basque companies in the safe incorporation of nanomaterials in their products and processes, are a clear response to the business development and revitalisation actions proposed in this strategy.

Although it is still too early to be able to analyse its evolution, the scientific and corporate progress achieved in the Basque Country in the fields of

nanoscience, micro and nanotechnology suggests that the region’s scientific/ technological and corporate capabilities are moving in the right direction towards the stated objectives, such as greater private R+D investment in these fields, an increased technological intensity of the Basque industrial framework and the generation of a greater competitive advantage in the Basque Innovation System.

There are currently 180 companies working in the field of micro- and/or nanotechnology in the Basque Country. The cross-over nature of these technologies is reflected in the identification of companies from more than 15 different industrial sectors, the majority of which have high growth perspectives. Thus, the activity in intermediate sectors such as steel, metallurgy and metallic products, or final sectors such as the automotive industry, health and pharmaceuticals, should be highlighted.

What really gives value to this complete system of research centres, companies and organizations in the Basque Country is its constant coordination and interaction, based on a new model of relations driven by the nanobasque Agency. A new system in which, as is the case in nanotechnology, each part is ordered in an innovative way and the set acquires new properties.

Without a doubt, this ambitious strategy demonstrates that the Basque Country wants to position itself firmly on the global map of nanoscience, micro and nanotechnologies through its big commitment to the very small.

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Invited Recent advances in fast imaging Raman technology for nano materials characterisation

Sébastien Maussang

Renishaw Ibérica S.A.U., Spectroscopy Products Division Gavà Park. C. Imaginació, 3, 08850 GAVÀ, Barcelona, Spain

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order of fifty milliseconds. The method also benefits from ‘on the fly’ data analysis resulting in real time image creation. This innovative approach allows the technique to succeed where others have failed: producing uncompromised data and images for small or large areas at speeds much greater than possible with competing methods. A number of materials examples will be shown to illustrate the benefits of this method and will demonstrate how information can be achieved on the nanometre scale.

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Raman spectroscopy continues to provide analytical solutions in a variety of material science applications offering chemical specificity on a micrometer scale.

The ability to create chemical and stress images by acquiring Raman spectra from an array of positions and then processing them to reveal the parameter of interest is a powerful technique. Traditionally, these spatially-related data have been collected by raster scanning the sample beneath the incident laser spot, typically in micrometer intervals. New approaches to Raman imaging have been developed that enhance the capabilities of modern Raman instruments that now have the ability to produce images on the nano scale.

The use of either high precision motorised stages or piezoelectric-controlled sample stages permits accurate and repeatable sample movements in intervals significantly smaller than the diffraction limited laser spot size. When used in conjunction with an atomic force microscope tip, feedback can be applied to ensure the sample’s surface remains in the plane of the laser focus, optimising efficiency. Topographic images of the surface can be correlated with Raman images as the data are acquired simultaneously. This approach is proving to be most useful in materials research and the study of semiconductor materials, particularly in assessing carbon nanotube structures, graphene film properties and in stress in silicon devices.

Other application areas include biological intracellular structure and tissue imaging.

Additionally, a new method of acquiring both 2D and 3D confocal Raman images has been developed – ‘Streamline’. Spectra are collected in parallel, rather than in series using the traditional methods. Shorter total acquisition times result, with high quality individual spectra recorded in the

Oral Mass production of high quality Graphene

Kazuo Muramatsu

muramatsu@incu-alliance.co.jp

Incubation Alliance,Inc. 1-2-25-D307, Wadayama-dori, Hyogo-ku, Kobe 6520884 Japan

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Incubation Alliance Inc. has used a proprietary high-speed CVD process to successfully masssynthesize graphene without the use of substrates, catalysts, or stripping. [1] “GRAPHENEFLOWER” (registered trademark) is a mass of graphene that has been grown into individual flower pedal shapes, which together form a unified mass of graphene. GRAPHENE FLOWER dispersions are composed of graphene that has been finely powdered while suppressing the adhesion of the graphene by placing masses of GRAPHENEFLOWER in an organic solvent and storing the powder in the solvent. Dispersions can also be composed of recovered supernatant produced by ultrasonic wave treatment separation and centrifugation of the graphene As a GRAPHENE FLOWER dispersion, it is possible to apply graphene to a variety of applications via coating graphene stabilized in an organic solvent to a substrate, primarily through a wet process, or by dispersing the graphene in a material. In addition, some of the potential production methods for realizing these applications can apply relatively simple generalpurpose devices and existing wet process technology. Such approaches could possibly design a resource/energy saving production process with high productivity.

There are many approaches to produce the graphene currently, but almost all process needs some removing process or exfoliation process with very low productivity. Incubation Alliance Inc has made an effort to develop a new production method in order to escalate its application, which is to synthesize nanocarbon materials with high productivity. Our new technology features to perform CVD simultaneously in a full reaction container and can obtain a very high productivity.

This method is possible to synthesize graphene with a high productivity, because CVD advances

simultaneously and 3dimensionally in a full reaction container, and substrate-free/catalystfree synthesis are possible. [2] Graphene Flower is available as a dispersion of 10μm shaped with 1 nm thick graphene, perfect for wet coating of flexible transparent conductive films, heat radiation sheets, lithium-ion battery electrodes, capacitor electrodes, etc.It is also available as a dispersion in the requested solvent, including water, IPA, NMP, PGMEA, etc. and applicable to all printable electronics via spray coating, bar coating, gravure printing, screen printing, etc. [3] This development has been supported by Ministry of Economy, Trade and Industry of Japan, “Strategic Foundational Technology Improvement Support Operation 2010-2012.”

References [1] K. Muramatsu and M. Toyoda, EP2436648 (A1).

[2] K. Muramatsu and M. Toyoda,EP2537801 (A1).

[3] K. Muramatsu, K. Sutani and M. Toyoda, Graphene2012 International Conference, Brussels, Belguim, 2012.4.10-13.

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Figure 1: Graphene Flower as grown.

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Figure 3: Graphene Flower Dispersion.

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Figure 2: FE-SEM for Graphene Flower surface.

Oral Nanotechnology, from technology push to market pull

Antonio Porro

antonio.porro@tecnalia.com Tecnalia, Parque Tecnologico de Bizkaia, Edif. 700, 48160 Derio, Spain

Since the year 2001 Nanotechnology has captured the attention of the Governments all around the world. The reason is simple: Its ability to modify the industrial competitiveness rules.

Nanotechnology is able to confer new functionalities to products, which in turn can be produced in a more effective way, using less raw materials and consuming less energy.

Consequently, a big effort on nanotechnologyrelated research is under way. The European Commission selected in its 2009 Communication [1], six Key Enabling Technologies (KETs) and nanotechnology was included among them.

Furthermore, the High-level Expert Group on Key Enabling Technologies [2] highlighted that those nations and regions mastering KETs will be at the forefront of future advanced and sustainable economies.

To transform this vision into a reality the acquired knowledge must be transferred to industry. The nature of nanotechnology offers a wide action field for entrepreneurship: New products that provide solutions to unsolved problems in an efficient way, which entail a great deal of new business opportunities. This presentation is related to this specific subject. More precisely, it is focused on the start-up generation process, from the achievement of a discovery to the negotiation with investors.

[2] European Commission High-level Expert Group on Key Enabling Technologies, Final Report, June 2011.

References

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[1] Commission Communication COM(2009)512: â&#x20AC;&#x153;Preparing for our future: Developing a common strategy for key enabling technologies in the EUâ&#x20AC;?.

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Oral Models for investment in R&D and Technology Transfer in Nanotechnology

Fernando Resina da Silva

frs@vda.pt

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In this context moreover, collaboration with companies at all stages of the knowledge creation process, not just the final marketing stage, is a significant means of ensuring that R&D is marketoriented and meets the needs of the market.

Collaboration between universities/research centres and companies, by encouraging the creation of market-oriented technologies, has benefits for all agents of the inventive/creative process: researchers, universities/research centres and companies.

Researchers will of course find it easier to obtain funding for their work, along with greater exposure and promotion of their projects in the market.

Research centres, for their part, will benefit from enduring partnerships with companies while at the same time carrying out projects in a more competitive R&D environment.

Companies have the advantage of obtaining, often at more accessible costs, specialist human resources with extensive know-how in their areas of activity and dedicated exclusively to the project in hand.

However, for effective collaboration, there are a number of requirements that must be taken into account, such as:  Internal regulations/policies: universities/research centres (and companies) must create internal rules that clearly frame their R&D activities and their policy with regard to intellectual property and technology transfer; 

Detailed project identification: the project must be properly identified, stating intended endpoints, terms of finance, deliverables, deadlines, ownership of IP and associated

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Topic under analysis This document analyses the main models that can be implemented to promote investment in research and development (R&D) processes and active collaboration between companies and nanotechnology research centres and institutions, with a view to implementing effective and productive models of technology transfer.

Models of collaboration / Technology Transfer The creation of innovative technological solutions in the context of nanotechnology that meet the effective needs of the market, calls for the development of – increasingly agile - mechanisms for sustained collaboration and partnership between universities/research centres and companies. Mechanisms that make it possible to identify, on the one hand, technological opportunities for and challenges to companies as they arise and, on the other, the best ways to overcome the challenges identified.

Sharing of knowledge and solutions between organisations that have specific scientific or technological knowledge – in the case of nanotechnology, in such fields as life sciences, nanoengineering, nanobiotechnology,… - and organisations that have an interest in putting that knowledge to use, particularly for purposes of commercial application, plays a key role in pursuing the objectives mentioned.

In this respect, in order for a company, and in particular a technology-based company, to position itself competitively in the nanotechnologies market, it is essential that it be capable of generating and using knowledge to develop new products, processes and services.

Collaboration with universities/research centres constitutes an excellent means of achieving this aim.

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Vieira de Almeida & Associados IT & Outsourcing Department Av. Duarte Pacheco 26, 1070-110 Lisboa, Portugal

royalties, payment of registration costs, and licensing terms, among other things. 

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Identification of opportunities and obstacles, project approval and supervision: universities/research centres and companies must, in analysing the project, correctly identify the opportunities and constraints associated with it, including its economic viability, equipping themselves with means of supervising the project once approved;

In practice, particular care must be taken over a series of matters that must be properly reflected in a contract between the interested parties (see the flow chart in figure 1 below). All of these points can take very different forms and have very different effects depending on what is agreed. This in turn may depend not only on the area of activity and the maturity of the market, but also on the commercial and legal models adopted, which can in many cases be related to the nature of the entity that proposes the project (company, several companies – which may even be competitors in the market – or a researcher /centre).

Figure 1: Collaboration between researchers, universities/research centres and companies

References

610

[1] Silva, Fernando Resina da; Mendonça, Helena Correia de; Vieira de Almeida & Associados; 2013.

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Oral High-speed 3D laser lithography with high NA-objectives for 3D micro and nanofabrication

Sofía Rodríguez

rodriguez@nanoscribe.de

Nanoscribe GmbH, Eggenstein-Leopoldshafen, Germany

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illustrative overview of the applicability of our DLW technology. Moreover, we evaluate fabrication possibilities of photonic colorized materials (see Fig. 4) and diffractive optical elements potentially employed for security labels and sensors.

References [1] S. Kawata et al., Nature 412 (2001), 697.

[2] www.nanoscribe.de [3] T. Bückmann et al., Adv. Mater., 24 (2012) 2710.

[4] J.H. Atwater et al., Appl. Physics Letters, 99 (2011) 151113.

[5] F. Klein et al., Adv. Mater., 22 (2010) 868.

[6] S. Tottori et al., Adv. Mater. 24 (2012) 709.

Figure 1: Micro-photonic parabolic light directors along the publication [4].

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Three-dimensional (3D) direct laser writing (DLW) based on two-photon polymerization allows for versatile fabrication of micro- and nanostructures for a large variety of applications [1,2]. Nowadays, DLW has been established as standard tool in many scientific research laboratories covering the demands of research areas such as photonics, micro-optics, microfluidics, tissue engineering, optical telecommunications and mechanical metamaterials.

Here, we present the combination of our technical advantages of DLW to meet more of the high demands of 3D micro and nanofabrication in the scientific community and industry. (i) Highest resolution is achieved by the use of high-NA (NA= 1.4) objectives, which allow for feature sizes down to 150 nm. (ii) Ultra-high precision positioning for 3D structuring carried out either by means of a sample scanning routine relative to a fixed laser focus or by scanning the laser beam inside the photoresist. (iii) Highspeed fabrication based on the latter scanning mode has been enabled by the integration of a galvo mirror system that deflects the laser beam for typical writing speeds of 20 mm/s or better. (iv) Limited structural heights due to the working distance of microscope objectives have been overcome with the inhouse developed 3D Dip-in Laser Lithography (DiLL) [3].

The combination of these developments paves the way for a broad range of applications. Here, we present results achieved by means of our 3D Laser Lithography system on 3D photonic crystals, artificial extracellular matrices for tissue engineering, micro- and nanofludic devices for microchannels, magnetic helical micromachines, photonic wire bonding and mechanical metamaterials. The following figures exemplified some of the above mentioned applications for an

Figure 2: Biocompatible 3D scaffold for cell studies in tissue engineering along the publication [5].

Figure 3: Magnetic helical micromachines, structures coated with nickel [6].

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Figure 4: Photonic colorized elements.

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Invited Recent Research & Development at American Elements Using Nanotechnology in Fuel Cells

Michael N. Silver

michael.silver@americanelements.com

American Elements 10884 Weyburn Avenue Los Angeles, CA

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platinum nanoparticles and coating “Bucky Balls” (C60 Nanoparticles) with platinum nanoparticles.

Current research showing how nanotechnology may solve the most vexing problems holding back full commercialization of fuel cells is discussed.

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Recent research at American Elements has shown how nanoscale materials can improve the performance of both Solid Oxide (SOFC) Fuel Cells and Proton Exchange Membrane (PEM) Fuel Cells; the two fuel cell technologies with the greatest industrial potential.

The greatest barrier to the use of solid oxide fuel cells (SOFC) in automotive and aerospace applications is the high temperature at which they operate (800°+ C). Nanoparticle usage is shown to reduce the operating temperatures of SOFCs, facilitating their possible usage in automobiles and other low temperature applications.

The typical electrolyte in SOFCs is yttria stabilized zirconia (YSZ). Research has shown that using nanoscale YSZ increases ionic conductivity at lower temperatures. Additionally, the typical SOFC anode is composed of a nickel cermet (NiO/YSZ). Using nanoscale NiO and YSZ to produce the cermet increases the area of electron conduction without reduction in gas path flow; further reducing operating temperatures.

Carbon nanotubes have the potential to reduce or eliminate the use of platinum in proton exchange membrane (PEM) fuel cells which has made them cost prohibitive for many uses. Research at American Elements has shown that use of multiwalled carbon nanotubes in replacement of carbon graphite dramatically increases the conductivity of the electrolyte. This may make it possible to replace expensive platinum with less expensive alternatives, such as palladium.

Another interesting area of ongoing PEM investigation involves the use of “controlled growth” platinum nanowires grown on carbon nanospheres. Similar research is underway at American Elements coating graphene with

Oral The strategic investment in a Europe of Knowledge and Innovation: challenges for the new Framework Programme Horizon 2020

Vasco Teixeira

vasco@fisica.uminho.pt

University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal

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In 2014 starts a new funding cycle for research and innovation in Europe, the Horizon 2020 which succeeds to the 7 Framework Programme (FP7, 2007-2013). The FP7 for research and technological development (RTD) still remains the EU’ main instrument for funding research in Europe till end of 2013 (budget of 53.3 billion euros). The FP7 supports research actions in priority thematic areas from which Medicine, Food, Agriculture, Nanotechnology, Manufacturing Technologies, ICT, Regions of Knowledge and Research for the benefit of SMEs can be highlighted.

The Horizon 2020 brings together all the current EU funding in the domain of Research and Innovation, including the Research Framework Programme (FP), innovation aspects of Competitiveness and Innovation Framework Programme (CIP) and EU contribution to the European Institute of Innovation and Technology (EIT). It will have a budget of around 86 billion euros. In addition, the Horizon 2020 will concentrate the resources in three distinct mutually reinforced priorities: Scientific Excellence, Industrial Leadership and Societal Challenges.

RTD and innovation activities are considered to be the key pillar of the EU’ strategy in order to create sustainable, inclusive growth and prosperity of its members. In this sense, the focus on RTD investments for each member state it is crucial to enable the economic growth, to boost industrial competitiveness and to further empower the development of EU’ regions.

Under the scope of H2020 it will be invested nearly €6 billion for the development of European Industrial capabilities in Key Enabling Technologies (that include: photonics and micro- and

nanoelectronics; nanotechnologies; advanced materials and advanced manufacturing and processing; and biotechnology).

In this talk it will be highlighted the main challenges in the Next Framework Programme from the perspective of research institutes and SME with focus on Key Enabling Technologies, in particular nanotechnology and related areas.

Acknowledgments: The author would like to acknowledge NanoValor Project – “Creation and Promotion of a Competitiveness Pole in Nanotechnology for the capitalization of R&D potential in the North of Portugal - Galicia Euroregion” (reference: 0585_NANOVALOR_1_P) cofunded by ERDF through the Operational Programme for Cross-border Cooperation SpainPortugal 2007-2013 (POCTEP) www.nanovalor.org

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