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QuantumDots Fundamentals,SynthesisandApplications
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QuantumDots Fundamentals,SynthesisandApplications Editedby
RakshitAmeta
JayeshP.Bhatt
SureshC.Ameta
Elsevier
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1.Introduction 1 SureshC.Ameta
1.1Introduction 1 1.1.1Advantages2 1.1.2Disadvantages3
1.2Uniquefeaturesofquantumdots 3
1.2.1Highsurface-to-volumeratio3
1.2.2Surfaceplasmonresonance3
1.2.3Quantumconfinementeffect4
1.3Classificationofquantumdots 4
1.3.1Core-typequantumdots4
1.3.2Core shellquantumdots5 1.3.3Alloyedquantumdots5
1.4Synthesisofquantumdots 8
1.4.1Top-downapproach8
1.4.2Bottom-upapproach9
1.4.3Methodsofsynthesis9
1.5Applicationsofquantumdots 9
1.5.1Solarcells10
1.5.2Sensors11
1.5.3Lightemittingdiodes11
1.5.4Photocatalysis11
1.5.5Hydrogengeneration12 1.5.6Biomedicals12 1.6Conclusion 13 References 13 2.Hydrothermalsynthesisofquantumdots 15 JayeshP.BhattandNehaGodha 2.1Introduction 15 2.1.1Advantages17
5.Coprecipitationsynthesisofquantumdots 77
MonikaJangidandSeemaKothari
5.1Introduction 77
5.1.1Advantages77
5.1.2Disadvantages78
5.2Classificationofcoprecipitation 78
5.3Synthesisofquantumdots 79
5.3.1Metaloxidequantumdots79
5.3.2Metalsulfides80
5.3.3Metalselenidequantumdots83
5.3.4Carbon-based84
5.3.5Graphene-based85
5.3.6Others87
6.Biogenicsynthesisofquantumdots 93
MeghaviGupta,InderjeetYadavandAbhilashaJain
6.1Introduction
6.4Fungi
7.Microwave-assistedsynthesisofquantumdots 115
ChetnaAmeta,YogeshwariVyas,PriyankaChundawatand Dharmendra
7.1Introduction 115
7.1.1Advantages116
7.1.2Disadvantages117
7.2Synthesisofcore-typequantumdots 117
7.2.1Oxidequantumdots118
7.2.2Sulfidequantumdots122
7.2.3Selenidequantumdots126
7.2.4Telluridequantumdots127
7.2.5Otherquantumdots129
7.3Synthesisofcore shellquantumdots 130
7.3.1TypeICSquantumdots131
7.3.2InversetypeICSquantumdots131
7.3.3TypeIICSquantumdots132
8.Sonochemicalsynthesisofquantumdots
GarimaAmetaandSeemaKothari
9.Applicationofquantumdotsinphotocatalysis
10.Applicationofquantumdotsinlight-emittingdiodes
10.2Displayandlighting
10.2.1Whitelight-emittingdiodes207
10.2.2Bluelight-emittingdiodes213
10.2.3Redlight-emittingdiodes217
10.2.4Greenlight-emittingdiodes219
10.2.5Orangelight-emittingdiodes222
10.2.6Yellowlight-emittingdiodes223
11.Applicationofquantumdotsinbiomedicaland biotechnologicalfields
AncaArm ˘ a¸seluandPriyankaJhalora
11.4.1Photoluminescencesensors255 11.4.2Chemiluminescencesensors257
12.Applicationofquantumdotsinsolarcells
ShwetharaniR,ChandanHunsurRavikumar,M.S.Jyothiand R.GeethaBalakrishna
12.1Introduction 277
12.1.1Basicstructureofquantumdotsensitizedsolarcells278
12.1.2Workingprincipleofquantumdotsensitized solarcells280
12.2Propertiesofquantumdots 281
12.2.1Energygaptuning281
12.2.2Multipleexcitongeneration283
12.3Synthesisofquantumdots 286
12.3.1Chalcogenidequantumdots286
12.3.2Perovskitequantumdots289
12.4Quantumdotsensitizedsolarcells
13.Applicationofquantumdotsinsensors
NeelamKunwar,HetalZalaandKushnumaParveen
14.Applicationofquantumdotsinphotosplitting
LumaM.Ahmed,ThaqeefM.Jawad,HamadH.Kadiumand JayeshP.Bhatt
Listofcontributors LumaM.Ahmed DepartmentofChemistry,CollegeofScience,Universityof Kerbala,Karbala,Iraq
ChetnaAmeta DepartmentofChemistry,M.L.S.UniversityUdaipur,Rajasthan, India
GarimaAmeta DepartmentofChemistry,M.L.S.University,Udaipur,Rajasthan, India
RakshitAmeta DepartmentofChemistry,J.R.N.RajasthanVidhyapeeth(Deemed tobeUniversity),Udaipur,Rajasthan,India
RameshwarAmeta DepartmentofChemistry,PAHERUniversity,Udaipur, Rajasthan,India
SureshC.Ameta DepartmentofChemistry,PAHERUniversity,Udaipur, Rajasthan,India
AncaArma ˘ s ¸elu DepartmentofElectricalEngineeringandAppliedPhysics,Faculty ofElectricalEngineeringandComputerScience,TransilvaniaUniversityof Brasov,Brasov,Romania
R.GeethaBalakrishna CentreforNanoandMaterialSciences,JainUniversity, Bengaluru,Karnataka,India
InduBhati Maribyrnong,VIC,Australia
JayeshP.Bhatt DepartmentofChemistry,PAHERUniversity,Udaipur,Rajasthan, India
PriyankaChundawat DepartmentofChemistry,M.L.S.UniversityUdaipur, Rajasthan,India
Dharmendra DepartmentofChemistry,M.L.S.UniversityUdaipur,Rajasthan, India
NehaGodha DepartmentofChemistry,PAHERUniversity,Udaipur,Rajasthan, India
MeghaviGupta DepartmentofChemistry,PAHERUniversity,Udaipur,Rajasthan, India
ChandanHunsurRavikumar CentreforNanoandMaterialSciences,Jain University,Bengaluru,Karnataka,India;PilotPlantDevelopmentandTraining Institute,KingMongkut’sUniversityofTechnologyThonburi,Thakam, Bangkok,Thailand
AbhilashaJain DepartmentofChemistry,St.Xavier’sCollege,Mumbai, Maharashtra,India
MonikaJangid DepartmentofChemistry,PAHERUniversity,Udaipur,Rajasthan, India
KanchanK.Jat DepartmentofChemistry,M.L.S.UniversityUdaipur,Rajasthan, India
ThaqeefM.Jawad DepartmentofChemistry,CollegeofScience,Universityof Kerbala,Karbala,Iraq
PriyankaJhalora DepartmentofChemistry,PAHERUniversity,Udaipur, Rajasthan,India
M.S.Jyothi DepartmentofChemistry,AMCEngineeringCollege,Bengaluru, Karnataka,India
HamadH.Kadium DepartmentofChemistry,CollegeofScience,Universityof Kerbala,Karbala,Iraq
SeemaKothari DepartmentofChemistry,PAHERUniversity,Udaipur,Rajasthan, India
NeelamKunwar DepartmentofChemistry,PAHERUniversity,Udaipur,Rajasthan, India
KushnumaParveen KhamisMushayt,AhadRafaidah,KingdomofSaudiArabia
ShwetharaniR CentreforNanoandMaterialSciences,JainUniversity,Bengaluru, Karnataka,India
AvinashK.Rai DepartmentofChemistry,PAHERUniversityUdaipur,Rajasthan, India
NeetuShorgar DepartmentofChemistry,PAHERUniversity,Udaipur,Rajasthan, India
ShubangVyas DepartmentofChemistry,PAHERUniversity,Udaipur,Rajasthan, India
YogeshwariVyas DepartmentofChemistry,M.L.S.UniversityUdaipur, Rajasthan,India
InderjeetYadav DepartmentofAppliedSciences,UniversityofTechnologyand AppliedSciences,Alkhuwair,Muscat,SultanateofOman
HetalZala 1197-1,Uchigashimacho,A-101,Gunma,Ota-Shi,Japan xiv Listofcontributors
Abouttheeditors Dr.RakshitAmeta hasathoroughlyfirstclasscareer,securingfirstposition inhisMSc.andwasawardedaGoldMedal.HewasalsogiventheFateh SinghAwardfromMaharanaMewarFoundation,Udaipurforhismeritorious performance.AftercompletionofhisPhD,heservedinHindustanZinc Limited,VedantaGroupfor1year.HehasservedinM.L.Sukhadia University,Udaipur;UniversityofKota,Kota,PAHERUniversity,Udaipur, andpresentlyisatJ.R.N.RajasthanVidyapeeth(DeemedtobeUniversity) Udaipur.Underhissupervision12PhDstudentshavebeenawardedPhDson variousaspectsofGreenChemistry.Hehasaround140researchpublications tohiscreditinjournalsofnationalandinternationalrepute.Hehasapatent tohiscreditaswell.Heisareviewerofaround50internationaljournals.Dr. RakshithassuccessfullyorganizedmanyNationalConferencesatUniversity ofKota,Kora;PAHERUniversity,Udaipur;andJ.R.N.Rajasthan Vidyapeeth,Udaipur.HehasdeliveredInvitedlecturesandchairedsessions in20nationalconferencesindifferentpartsofthecountry.Dr.Rakshithas servedasacouncilmember(2011 13and2020 22)andassociateeditor, PhysicalChemistrySection(2014 16),scientist-in-chargeintheIndustrial andAppliedChemistrySection(2014 2016)oftheIndianChemical Society,Kolkata,andexecutivecouncilmember(2012 14)andZonal Secretary(2016 18)ofIndianCouncilofChemists,Agra.Hehadbeena recipientoftheDr.U.C.PantMemorialAward,IndianChemicalSociety, Kolkata.HehaswrittensixbookspublishedbyTaylor&Francis,UK; AcademicPress,Elsevier;AppleAcademicPress,andanumberofchapters inbooksbythesepublishersandalsoNovaPublishers;Trans-Tech Publications,Springer,etc.Hismainresearchfocusisonphotochemistry, greenchemistry,microwave-assistedreactions,environmentalchemistry, wastewatertreatment,nanochemistry,solarcells,bioactive&conducting polymers.
Dr.JayeshP.Bhatt receivedhisMSc.fromRSTMNagpurUniversityin 2011.HewasawardedhisPhDintheyear2019fromPAHERUniversity, Udaipur.Since2019hehasbeenworkingasanassistantprofessorinthe DepartmentofChemistry,PAHERUniversity,Udaipur.Hehasdone researchinthefieldofnanomaterials,particularlyquantumdots,wastewater treatment,etc.Dr.Jayeshhaspublished11researcharticlesinjournalsof
nationalandinternationalreputeandcontributed12chapters.Currentlyfour PhDstudentsareworkingunderhissupervision.Hehasbeenhonoredwith theYoungScientistAwardataninternationalconferencein2018,Best PosterPresentationin2019,BestOralPresentationin2020,andSenior ScientistAwardforBestOralPresentationinaninternationalconference (2021).
Prof.SureshC.Ameta obtainedhismaster’sdegreefromtheUniversityof Udaipurandwasawardedagoldmedalin1970.HeobtainedhisPhDdegree fromVikramUniversityin1980.Hehasservedasprofessorandhead, DepartmentofChemistry,NorthGujaratUniversityPatan(1994)andM.L. SukhadiaUniversity,Udaipur(2002 05)andhead,DepartmentofPolymer Science(2005 08).Healsoservedasdean,P.G.Studiesforaperiodof4 years(2004 08)inM.L.SukhadiaUniversity,Udaipuranddean,Facultyof Science,PAHERUniversity(2011 18).Now,heisservingasprofessorof eminence(distinguishedprofessor),FacultyofScience,PAHERUniversity, Udaipur.Prof.Ametahasaround50yearsofexperienceofteachingand research.Hehassuccessfullyguided108studentsthroughtheirPhDs.Prof. AmetahasoccupiedtheprestigiouspositionofPresident,IndianChemical Society,Kolkata(2000 01)andisnowalifelongadvisor.Hewasawarded anumberofprizesduringhiscareer,includingtheNationalprizetwicefor writingchemistrybooksinHindi,Prof.M.N.DesaiAward,Prof.W.U. MalikAward,ScientistoftheYearAward,NationalTeacherAward,Prof. G.V.BakoreAward,andaboveall,LifeTimeAchievementAwardsfrom theIndianChemicalSociety(2011),Kolkata,IndianCouncilofChemists, Agra(2015)andAssociationofChemistryTeachers,Mumbai(2018).Dr. Ametahasmorethan400researchpapersand36bookstohiscredit.Hehas contributedchaptersinbookspublishedbyTrans-Tech,Switzerland;Nova Science;Taylor&Francis;Elsevier;Springer;andAppleAcademicPress. Hehas12bookstohiscredit,includingGreenChemistry,Microwave AssistedOrganicSynthesis,SolarEnergyConversionandStorage,Group Theory,Photocatalysis,Storage,AdvancedOxidationProcessesforWaste WaterTreatment,Sonochemistry,etc.TheIndianChemicalSociety,Kolkata publishedaspecialissueoftheJournalofIndianChemicalSocietyonhis 60thbirthdayin2008andalsoinstitutedaNationalPrizeinhishonorasthe Prof.SureshC.AmetaAwardtobegiventoaSeniorScientistofthecountry from2003onwards.
Preface Nanomaterialshaverevolutionizedmanyresearchareasduetotheirunique optical,electronic,andotherproperties.Quantumdotshavelowerdimensions(2 10nm)inthenanometricrange.Thesequantumdotshaveahigh surfacearea-to-volumeratio,aquantumconfinementeffect,andsurface Plasmonresonance.Assuchtheyhavegreatpotentialforapplicationsindifferentfields.Thepresentbookisdividedintothreeparts.First,itdealswith thebasicsorfundamentalsofquantumdots,whilethesecondpartisdevoted tovariousmethodsofsynthesizingquantumdots,includinghydrothermal, sol gel,laserablation,coprecipitation,biogenic,microwave-assisted,and sonochemical.Thethirdpartofthepresentbookisdevotedtothepossible applicationsofquantumdotsintheseareas,suchasphotocatalysis,solar cells,light-emittingdiodes,sensors,photosplittingofwater,targeteddrug delivery,cancertherapy,etc.Thetimeisnotfaroffwhenquantumdotswill findafirmfooting,andtheywillbeconsideredamiracleparticleinthe yearstocome. RakshitAmeta
JayeshP.Bhatt
SureshC.Ameta
Thispageintentionallyleftblank
Chapter1 Introduction SureshC.Ameta
DepartmentofChemistry,PAHERUniversity,Udaipur,Rajasthan,India
1.1Introduction Thematerialsinthenanorange(1 100nm)aretermedasnanomaterials. Therearesomenanostructuredmaterialswithsizeinthe2 10nmrange, suchnanomaterialsarecalledquantumdots.Thenamequantumdotwas givenbecauseitisatinyspeckofmatter(2 10nm),whichisverysmall, justlikeasinglepointordot.Inotherwords,itisconsideredzerodimensional.Theparticlesinsidethequantumdotthatcarryelectricity(electronsandholes)aretrapped(constrained)andhavewell-definedenergy levels,followingthelawsofquantumtheoryjustlikeindividualatoms. Thereareafewdozentohundredsorafewthousandatoms.Althoughthese quantumdotsarenanocrystals,theybehavemorelikeindividualatoms; therefore,theyhavebeennicknamedartificialatomsalso.
Quantumdotshavequantizedenergylevels.Onexcitationanelectronin thequantumdotjumpstoahigherenergylevel.Whenthisexcitedelectron returnstoalowerlevel,thequantumdotemitsaphotonoflightwiththe sameenergyaswasoriginallyabsorbed.Thecoloroftheemittedlight dependsontheenergylevelsanditvariesfromonequantumdottoanother. Theenergylevelsofquantumdotsaregovernedbytheirsizeandnotthesubstancefromwhichitwasmade.Thequantumdotsandtheirapplicationhave beenexcellentlyreviewedbydifferentresearchers(e.g., Jamiesonetal.,2007; Jacaketal.,2013; Michler,2003; Wuetal.,2019; Molaei,2019; Divsar, 2020; Nairetal.,2020; AbdRanietal.,2020; Vyasetal.,2021).
Asmallquantumdothasalongerbandgap,andhenceitrequiresmore energytoexciteitselectron.Asthefrequencyofemittedlightisproportional totheenergy,smallerquantumdotsemitradiationofhigherenergyorfrequency,thatis,shorterwavelengths,whilelargerquantumdotshaveclosely spacedenergylevelsandemitphotonsoflowerenergyorfrequency,thatis, longerwavelengths.Itmeansthatasthesizeofquantumdotsincreases,the quantumdotwillemitphotonswithlowerenergyorfrequencyandhigher wavelengthandviceversa.Thisispresentedin Fig.1.1
QuantumDots
Whenthesizeofthequantumdotisgreater(diameter5 6nm),thenit willemitradiationoflargerwavelengthswithorangeorredcolors.Onthe otherhand,ifthesizeofquantumdotissmaller(diameter2 3nm),thenit willemitradiationofshorterwavelengthswithblueandgreencolors.But theactualcolordependsontheexactsizeandcompositionofthequantum dots.Accordingly,achangeincolorcanbeobservedastheparticlesizeof quantumdotsvaries.Thisisclearlyvisiblein Fig.1.2
1.1.1Advantages Thesearesomeadvantagesofquantumdotsandtheseare:
● Highquantumyield
● Highphotostability
● Symmetricandnarrowpeakofemission
FIGURE1.1 Relationshipbetweensizeofquantumdots,energyorfrequencyofemittedlight, andwavelengthofradiation.
FIGURE1.2 Changeincolorwithsizeofquantumdots.
● Longerlifetime
● Possibilitytocontrolemissionbychangingthesizeandstructureof quantumdots
● Brightness
● Resistancetophotobleachingascomparedtoorganicfluorophores
● Requiredsmallamountofenergyforexcitation(blueorUVradiation)
1.1.2Disadvantages
Apartfromtheadvantages,therearesomedisadvantagesofquantumdots suchas:
● Hightoxicity,whenusedinvivo
● Declineoffluorescenceexponentially
● Blinkingofquantumdotsmakestheminvisiblesometimes
● Quantumyielddeterioration
● Extendedlifetimemaycreateaproblemwhenrapiddegradationis required
1.2Uniquefeaturesofquantumdots Variouspropertiesofnanomaterialsorquantumdotschangeastheirsizeis changed.Atthisstage,thepercentageofatomsavailableatthesurfaceofa semiconductingmaterialbecomesquitesignificant.Therearethreemainfactorsthatareconsideredresponsibleforsomeuniquepropertiesinnanomaterialsaswellasquantumdots,whicharesignificantlyortotallydifferentfrom theircounterpartmicro-,macro-,orbulkmaterials.Theseare:
1.2.1Highsurface-to-volumeratio Asthesizeoftheparticleapproachesafewnm,thesurfacearea-to-volume ratioandsurface-to-bulkatomratiobothincreasedramatically.Depending onthecompositionandstructureofthematerialusedtoproducenanoparticlesorquantumdots,propertieslikeabsorptionoremissionwavelength,solubility,transparency,color,catalyticbehavior,conductivity,meltingpoint, etc.arechangedonlybyvariationinthesizeoftheparticle.Itleadstosome interestingbehaviorsofquantumdots.
1.2.2Surfaceplasmonresonance Surfaceplasmonresonance(SPR)isthecollectiveoscillationofvalence electronsinasolidstimulatedbyincidentlight.Sucharesonancecondition isestablishedwheneverthefrequencyoflightphotonsmatchesthenatural frequencyofoscillatingsurfaceelectronsagainsttherestoringforceofthe positivenuclei.ThisSPRinnanometricstructuresistermedaslocalized
SPR(LSPR).LSPRsarecollectiveoscillationsofelectronchargeinmetallic nanoparticlesorquantumdotsthatareexcitedbylight.Solutionscontaining nanoparticlesorquantumdotsofmetals(gold,silver,etc.)arecoloreddueto theSPRoftheparticles.Somepropertieslikeconductivity,dispersible nature,catalyticbehavior,opticalproperties,etc.changewithdifferentsurfacepropertiesoftheparticle.
1.2.3Quantumconfinementeffect Thequantumconfinementeffectcanbeobservedoncethediameterofany materialreachesthesamemagnitudeasthedeBrogliewavelengthofan electronwavefunction.Whenmaterialsaresosmall,theirelectronicand opticalpropertiesdeviatesubstantiallyfromthoseofbulkmaterials.Here, energylevelsarenotcontinuousbutarequantized,thatis,discrete,and thereforethesematerialsintherangeofnanosizeorthesizeofquantumdots exhibitthequantumconfinementeffect.
1.3Classificationofquantumdots Quantumdotsareclassifiedmainlyintothreetypesandtheseare:
● core-typequantumdots,
● core shellquantumdots(CSQDs),and
● alloyedquantumdots.
1.3.1Core-typequantumdots Thesequantumdotscanbesinglecomponentmaterials,whichhaveuniform internalcompositions.Thepropertiesofthesecore-typenanocrystalssuchas photo-andelectroluminescencecanbefine-tunedjustbysimplychanging thecrystallitesize.Theexamplesofcore-typequantumdotsarechalcogenides(sulfides,selenides,ortellurides)ofmetalslikecadmium,zinc,orlead (Fig.1.3).
FIGURE1.3 Core-typequantumdots.
1.3.2Core shellquantumdots Theluminescentpropertiesofquantumdotsareduetorecombinationof electron holepairs(excitons)throughradiativepathways.Thedecayofan excitoncanalsooccurvianonradiativemethods,whichreducesthefluorescencequantumyield.Oneofthepossiblemethodstoimproveefficiencyand brightnessofthesenanocrystalsistogrowashellofasemiconductingmaterialwithhigherbandgaparoundit.Suchparticles,wheresmallregionsof onematerialareembeddedinanotherwithawiderbandgap,aretermed CSQDsorcore shellsemiconductingnanocrystals(Fig.1.4).Iftheorderis reversed,thentheyarecalledreversetypequantumdots,whereashellis insidethecorestructure(Fig.1.5).Coatingofquantumdotswithsomeshells improvesthequantumyieldjustbypassivizingnonradiativerecombination sites.Thisalsomakesthemmorerobusttoprocessingconditions,sothat theycanfinduseinvariousapplications.CSQDsareclassifiedintotwo types:
● Core shelltype-Iquantumdots(Figs.1.6and1.7)
● Core shelltype-IIquantumdots(Figs.1.8and1.9)
1.3.3Alloyedquantumdots Althoughelectronicandopticalpropertiesofaquantumdotcanbetunedby justchangingitscrystallitesize,eventhensomeproblemsarefacedinmany applicationswherevertherearesomerestrictionsonsize.Propertiesof
FIGURE1.4 Core shelltypequantumdotswithvariousarrangementsofcore shell.
FIGURE1.5 Core shelltype I:(A)normal,and(B)reversedquantumdots.
FIGURE1.6 Energydiagramofcore shelltype I:(A)normaland(B)reversedquantum dots.
quantumdotshavingmulticomponentscanbetunedwithoutanychangein crystallitesize.Suchmulticomponentsystemsarecalledalloyedquantum dots(homogeneousandgradientinternalstructures)anditispossibletotune theirelectronicandopticalpropertiesbychangingtheirinternalstructure andcomposition.Thesealloyedquantumdotsarefabricatedbyalloyingany twosemiconductorswithdifferentbandgaps(Fig.1.9).Thesequantumdots showsomeinterestingproperties,whicharesometimesverydifferentfrom thepropertiesoftheiroriginalbulkcounterpartsorparentsemiconductors. Theycanbehomogeneousinnatureorwithaparticularzonerichinaspecificelement.
FIGURE1.7 Core shelltype IIquantumdots.(A)Boththebands(conductionandvalence) ofshellarehigherthancoreand(B)Boththebandsofshellarelowerthanthecore.
FIGURE1.8 Energydiagramofcore shelltype IIquantumdots.
FIGURE1.9 (A)Specificelement(Te-orSe-)richalloyedquantumdots,and(B)homogeneousalloyedquantumdots.
