Improving performance of polymer solar cells based on PSBTBT/PC71BM via controlled solvent vapor annealing

Controlled solvent vapor annealing (C-SVA) is a powerful tool to control the morphology for high performance polymer solar cells (PSCs). In this work, the PSCs employed a blend of poly[(4,4'-bis(2-ethylhexyl) dithieno[3,2-b:2',3'-d] silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)- 4,7-diyl] (PSBTBT) and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) is used to show this case. The solar cells upon C-SVA give Power Conversion Efficiency (PCE) of 5.40%, in contrast to 4.14% for the pristine and 4.70% for the thermally annealed devices. The increased PSBTBT concentration on the bottom surface of the C-SVA treated film favors charge carriers transportation to the anode, which contributes to the increased hole mobility of the photoactive layer and thus the device performance. (C) 2013 Elsevier B.V. All rights reserved.