Main-chain poly(fullerene) multiblock copolymers as organic photovoltaic donor–acceptors and stabilizers

Abstract

A multi-block copolymer based on main-chain fullerene repeating units is used in organic photovoltaic devices for the first time. A poly(fullerene) (PFDP) is linked at the chain-ends to poly(3-hexylthiophene) (P3HT) to give poly[poly(3-hexylthiophene)-block-poly{([1,4]-fullerene)-alt-[1,4-dimethylene-2,5-bis(cyclohexylmethyl ether)phenylene]}] (P3HT-b-PFDP). While normal devices give poor results, inverted architectures result in near 50-fold improvements in performances to a block copolymer efficiency of 2.8% for this novel system. PFDP-b-P3HT is also employed as an additive to P3HT:PCBM bulk heterojunction devices and demonstrates increases from 3.6% to 4.2%, and remarkably gives a stable flat-line efficiency over the time studied.