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L2.5.1

Fabrication of Nanorod Arrays for Organic Solar Cell Applications Susan Huang, Harry Efstathiadis, and Pradeep Haldar College of Nanoscale Science and Engineering, The University at Albany - SUNY Hee-Gyoun Lee Korean Polytechnic University, Siheung, Korea Brian Landi, and Ryne Raffaelle NanoPower Research Laboratory, Rochester Institute of Technology

ABSTRACT We report on a novel use of nanorod arrays for organic based solar cell devices. A metal foil with copper nanorods attached to the surface was developed by electrodepositing copper from a copper sulfate solution into an anodic alumina oxide (AAO) template that had been coated with a metal on one side. The AAO membrane was dissolved in NaOH leaving behind an aligned array of copper nanorods. This nanorod array was evaluated to explore the possibility of increasing the power conversion efficiency of organic solar cells. Nanorod array characteristics were investigated by focus ion beam, scanning electron microscopy, and x-ray diffraction spectroscopy. A solar cell device was made by applying a polymer layer of poly(2methoxy-5-(3’,7’-dimethyloctyloxy)-1,4-phenylene-vinylene) (MDMO-PPV) mixed with 6,6 phentl-C61-butyl acid-methylester (PCBM) onto the copper nanorod array and sandwiching it with a film of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) applied onto a indium tin oxide coated glass substrate. INTRODUCTION Fabricating solar cells from organic materials is a promising method for inexpensive, flexible photovoltaics. Current efficiencies of organic solar cells are still less than 4% but there is a large effort on developing methods of increasing efficiencies. One of these methods is to embed nanomaterials into photoactive polymer matrix. Nanomaterials that have been incorporated into organic solar cells include chemically modified fullerenes [1,2], single wall carbon nanotubes [3], and nanorods [4] to increase exciton dissociation and carrier transport. Organic solar cells with colloidal nanorods embedded in the polymer matrix have been demonstrated to have relatively high efficiencies of 1.7% [5]. We plan to explore the effect on device efficiency of polymer solar cells with embedded aligned nanorod arrays. Metallic [6] and semiconducting [7] nanorods have been previously fabricated by electrodeposition into a template. Electrodeposition offers a simple alternative solution for high yield production of nanoparticles and nonorods compared to other methodologies developed for the synthesis of metal nanostructures. The use of nanorods is expected to increase the efficiency of the device because each nanorod could provide a direct path to the electrode. Metallic nanorod arrays have been prepared by electrodeposition into anodic alumina oxide (AAO) templates [8,9] for organic solar cell applications and characterized by scanning electron microscopy (SEM), x-ray diffraction spectroscopy (XRD) and focus ion beam

L2.5.2

(FIB) microscopy. These nanorod arrays have been incorporated into the polymer poly(2-methoxy-5-(3’,7’-dimethylo