In 2015, Wang et al. synthesized a

In 2015, Wang et al. synthesized a bay-linked PDI dimer, called SdiPBI-S (S7) (Fig. 9), inwhich sulfur atoms were incorporated into the perylene cores[123]. SdiPBI-S exhibits a twisted molecular configurationbecause of the steric repulsion between two modified PDIs. Theincorporated sulfur atoms resulted in enhanced light absorptionand suitable energy levels. Combining with a well-matched ptype polymer, PDBT–T1 (Fig. 2) as the donor, OSCs based onSdiPBI-S achieved a PCE up to 7.16%. The analog of SdiPBI-Swas further synthesized by replacing sulfur atoms with seleniumatoms, SdiPBI-Se (S8) (Fig. 9), which showed higher electronmobility due to the loose electron cloud of the outmost p orbitalof selenium [124]. To characterize the photovoltaic performance,BHJ OSCs based on PDBT–T1/SdiPBI-Se were fabricated.