High-Efficiency Polymer Solar Cells Over 13.9% With a High VOC Beyond 1.0V by Synergistic Effect of Fluorine and Sulfur

A novel phenyl substituted benzo(1,2-b:4,5-b')dithiophene (BDT) derivative containing both fluorine and sulfur atoms is designed and synthesized. Furthermore, a wide bandgap polymer PBTA-PSF based on the derivative shows a low highest occupied molecular orbital energy level and slightly reduces the donor materials' optical bandgap, which has a complementary absorption with a narrow-bandgap n-type small molecule ITIC. As a result, a power conversion efficiency of 13.91% is achieved with a high open-circuit voltage of 1.01V, and a large short-circuit current density of 18.51mAcm(-2). The result demonstrates that PBTA-PSF is a promising candidate for high-performance donor and phenyl-containing BDT derivatives and has potential in the design of high-performance polymers for organic photovoltaics.