A benzo[ghi]-perylene triimide based double-cable conjugated polymer for single-component organic solar cells

Single-component organic solar cells (SCOSCs) with high stability and simplified fabrication process are supposed to accelerate the commercialization of organic photovoltaics. However, the types of photo-active materials and photovoltaic performance of SCOSCs are still far lagging behind the bulk-heterojunction type organic solar cells (BHJ OSCs). It is still an arduous task to introduce new photo-active materials into SCOSCs, aiming to improve the efficiencies of SCOSCs. One feasible way is to construct double-cable polymers with new structures and tune conformation, morphology and mobility for the improvement in power conversion efficiencies (PCEs). Hence, in this work, we constructed a new double-cable polymer PBTT-BPTI by introducing fused core 5,7-dibromo-2,3-bis(2-ethylhexyl)benzo[1,2-b:4,5-c']dithiophene-4,8-dione (TTDO) into the main backbone and benzo[ghi]-perylene triimide (BPTI) unit into the side chain. Both of the two units show strong electron-withdrawing property, which are expected to broaden absorption spectra and enhance intermolecular interaction. The double-cable polymer exhibited a broad absorption in the range of 300-700 nm with an optical band gap (E-g) of 1.79 eV. The PCE of PBTT-BPTI-based SCOSCs was 2.15%, which may be limited by the unconstructed efficient electron transporting channels. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.