Synthesis and photovoltaic properties of alkylthiothiophene modified benzodithiophene polymer

Abstract Here, we report a facile molecular engineering approach with alkylthio and fluorine atom modified the conjugated side chain of quinoxaline-based polymer, namely DTFFQx-TS, which afforded lower highest occupied molecular orbital energy level and enhanced interchain interactions. The conventional devices based on DTFFQx-TS:ITIC exhibited the power conversion efficiency (PCE) of 5.26% with a remarkably high open circuit voltage ( V oc ) of 0.99 V. This work not only provides a newly efficient candidate of quinoxaline acceptor block modified with fluorinated conjugated side chain, but also achieves high V oc copolymers for polymer solar cells via the synergistic effect of fluorination and side chain engineering strategies.