The investigation of donor-acceptor compatibility in bulk-heterojunction polymer systems

Abstract

The fullerene derivative, indene-C-60 bisadduct (ICBA), has been introduced into poly(3-hexylthiophene) (P3HT) to improve the efficiency of P3HT-based devices. However, we found that ICBA is not suitable for most low bandgap polymers. In this study, we have correlated the cell performance with surface energy between the donor and acceptor materials in a bulk-heterojunction cell. These results show that higher photocurrent can be attributed to the morphology improvement induced by larger surface energy difference (Delta gamma) between the low bandgap polymer and fullerene. These results also suggest that synthetic strategies which adjust the Delta gamma between donor and acceptor should be considered. (C) 2013 AIP Publishing LLC.