Performance improvement of polymer solar cells by using a solvent-treated poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) buffer layer

Photovoltaic performance of the polymer solar cell (PSC) based on poly(3-hexylthiophene) (P3HT) as donor and [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM) as acceptor was improved by using the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) modification layer treated by ethanol or 2-propanol. Power conversion efficiency (PCE) of the PSC based on P3HT: PCBM (1:1, w/w) with the 2-propanol-treated PEDOT: PSS modification layer reached 4.74%, in comparison with a PCE of 3.39% for the PSC with the PEDOT: PSS layer without the organic solvent treatment. The enhanced performance of the PSCs is attributed to higher conductivity and optimized surface morphology of the PEDOT:PSS layers treated by the organic solvent. (C) 2011 American Institute of Physics. [doi:10.1063/1.3600665]