Two TPD-Based Conjugated Polymers: Synthesis and Photovoltaic Applications as Donor Materials

Abstract

Two conjugated thienopyrrolodione-thiophene-vinyl-thiophene (TPDTVT)-based polymers, with one of them having an additional cyano (CN) group attached to the TVT building block, are synthesized and incorporated in photovoltaic device as electron-donating materials. Both TPD-TVT and TPD-TVTCN showed good thermal stability and appropriate solubility in chlorinated solvents, but they exhibited quite different optoelectrochemical and photovoltaic properties. The stronger intermolecular interactions of TPD-TVTCN, compared to TPD-TVT, lead to enhanced aggregation in blends with PC71BM. The domain sizes within 15-20 nm and improved molecular packing in TPD-TVTCN:PC71BM blend films result in better photovoltaic performance of TPD-TVTCN:PC71BM device compared to the device employing TPD-TVT.