A new oligobenzodithiophene end-capped with 3-ethyl-rhodanine groups for organic solar cells with high open-circuit voltage

摘要

A new solution-processable small-molecule donor material,named DRBDT3,comprised of oligobenzo[1,2-b:4,5-b']dithiophene as the backbone and 3-ethyl-rhodanine as the end-capped group has been designed and synthesized for application in organic photovoltaic cells.The oligobenzodithiophene derivative exhibits an absorption band from 300 to 640 nm.The film of DRBDT3 shows highly long-range ordering assembly and high mobility of 1.21×10 4 cm2 V 1 s 1.The new molecule shows a deep highest-occupied molecular orbital energy level.The device based on DRBDT3 as the donor and PC71BM as the acceptor exhibits a power conversion efficiency of 4.09%with a high open-circuit voltage of 0.99 V under AM.1.5G illumination(100m W cm2).