Perylene Diimide Hexamer Based on Combination of Direct and Indirect Linkage Manners for Non-fullerene Organic Solar Cells

Perylene diimide (PDI) is one of the most intensively studied building blocks for the construction of non-fullerene acceptors (NFAs). In this contribution, based on combination of the direct and indirect linkage manners of PDI units at the bay position, a propeller-shaped PDI hexamer T-DPDI was designed and synthesized. The singly bonded PDI dimer DPDI and the benzene ring cored PDI trimer TPDI were synthesized for comparison. The photovoltaic performances of these three PDI derivatives were investigated using the commercially available PTB7-Th as electron donor. A best power conversion efficiency (PCE) of 6.58% was obtained for T-DPDI based organic solar cells (OSCs), which is higher than those of DPDI and TPDI based ones. The superior photovoltaic performance of T-DPDI can be ascribed to its stronger absorption and more favorable morphology. This study presents an interesting example of improving the photovoltaic performances of PDI based NFAs by hybridizing the direct and indirect linkage manners.