Synthesis and Photovoltaic Properties of a Tricyanated Perylene Diimide Trimer

Abstract

Cyano groups have been widely used in polymeric donor materials and acceptor–donor–acceptor (A–D–A)-type nonfullerene acceptors. However, they have not yet been introduced into PDI-based materials. To fill this research gap, we synthesized a ring-fused cyanated PDI trimer as the nonfullerene acceptors in organic solar cells to investigate the impact of cyano groups on the photoelectronic and photovoltaic properties. Cyano groups exhibit steric hindrance intermediate between that of fluorine and chlorine atoms, which twists the molecular backbone and thereby inhibits aggregation more efficiently. Concurrently, its strong electron-withdrawing ability lowers both the molar absorptivity and the frontier molecular orbital levels. A power conversion efficiency (PCE) of 4.79% is achieved with a Voc of 0.69 V, a Jsc of 12.93 mA·cm–2, and an FF of 53.67% when blended with one narrow band gap polymeric donor, PBDF-Cl. This work fills the knowledge gap in illustrating the cyanation effects on PDI-based electron acceptors and provides valuable guidelines for designing cyanated photovoltaic materials.