Efficiency enhancement of polymer solar cells by localized surface plasmon of Au nanoparticles

We demonstrate the improvement of power conversion efficiency (PCE) in bulk heterojunction polymer solar cells based on blended poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester by introducing 40 nm Au nanoparticles (NPs) with various concentrations. The Au NPs were deposited on indium-tin-oxide (ITO) substrates by spin-coating from colloidal solution prior to deposition of poly (3,4-ethylene dioxythiophene: poly (styrene sulfonate) (PEDOT:PSS) buffer layer. It has been found that both short-circuit current density and PCE increase after incorporating Au NPs between ITO and PEDOT: PSS layer, and a suitable area density of Au NPs is required to achieve a maximum enhancement of device efficiency. The PCE of solar cells has been increased from 3.50% to 3.81% with 0.9wt.% Au NPs. The PCE enhancement is attributed to the localized surface plasmon excitation of Au NPs. The method employed herein is a kind of simple and convenient solution process, and it has great potential in future practical applications. (C) 2013 AIP Publishing LLC.