College of Engineering
College of Engineering
POLY(3-HEXYLTHIOPHENE) AS AN ORGANIC HOLECONDUCTOR IN EXTREMELY THIN ABSORBER PHOTOVOLTAICS
Paul Lachaud Chemical Engineering
Dr. Jason Baxter Faculty Mentor Chemical & Biological
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The purpose of this project is to investigate Poly (3‐ hexylthiophene) (P3HT) as an organic hole‐conducting (p‐ type) layer in organic‐inorganic Extremely thin absorber (ETA) solar cells in planar and nanowire array morphologies. ETA layer provides high surface area with a thinner layer, leading to lower charge recombination by having a thin ilm absorber coated on geometrically structured material. Organic polymers are appealing in solar cells because of their potential to be cheaply processed on large scale production through roll‐to‐roll processing. Poly(3‐hexylthiophene) is a promising polymer for photovoltaic applications due to its high charge mobility compared to other polymers. In these cells, Zinc Oxide nanowires (ZnO NW) prepared by chemical bath deposition (CBD) or ZnO thin ilms prepared by dip‐coating are utilized as the electron acceptor (n‐type). Cadmium Selenide (CdSe) deposited position is utilized as a light absorbing layer between the transparent n‐type and p‐type materials. The P3HT was deposited on the ZnO core/CdSe shell nanowires with a 2% by weight solution of P3HT in Chlorobenzene by spin coating. Scanning electron microscopy (SEM) show that P3HT in iltrates the ZnO NW/CdSe arrays. Further experiments will be completed to determine the effect of P3HT compared to Poly(3, 4‐ethylenedioxythiophene) (PEDOT) on the current‐voltage characteristics of these cells in various ZnO nanowire and planar arrangements.
STAR Scholars Summer Showcase 2011
CONTROLLED GROWTH OF NANOWIRES FOR SOLAR CELL APPLICATIONS An extremely thin absorber (ETA) solar cell is a cell that has a high solar energy conversion rate. It has an n‐i‐p Daniel McPherson semiconductor arrangement that is composed of electron carrier, absorber, and hole carrier layers. To create the ETA Chemical solar cells, zinc oxide (ZnO) has been selected as the primary Engineering electron carrier, cadmium selenide as the absorber layer, as well as a number of hole carriers such as electrolyte solutions of and potassium ferrocyanide, copper thiocyanate, and P3HT. In order to maximize ef iciency in ETA solar cells, nanowire arrays have been used to decrease the thickness of the absorbing layer in the cell while still containing the same Dr. Jason volume of the absorbing layer compared to a planar cell. Baxter However, there have been problems when trying to deposit the hole conducting layers of the cell on top of ZnO nanowires Faculty Mentor covered in cadmium selenide due to a lack of space between Chemical & Biological the wires. In response, a method is being developed to create Engineering a less dense array of ZnO nanowires through use of an extremely thin layer of TiO2 above a dip‐coated ZnO seed layer. This layer was created by spin coating a solution of .033M titanium isopropoxide and .033M diethanolamine and is believed to block the nucleation of nanowires on the ZnO seed layer so that the number density of nanowires decreases.
STAR Scholars Summer Showcase 2011
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