Effective design of novel low band gap acceptors for non-fullerene solar cells via modulating molecular planarity and F atom substitution

Abstract Due to the highly tunable molecular energy levels and potential for reducing synthesis costs, increased efforts have been devoted to developing non-fullerene acceptors. Herein we report two novel low band gap NF-SMAs for OSCs, namely IDBTC and IDBTCF. Thiophene-substituted benzothiadiazole is introduced between the donor and acceptor to regulate the coplanarity of the molecule and enhance intramolecular push-pull effect. In addition, the fluorine atom was introduced into the benzothiadiazole to study the effect of fluorination on the properties of NF-SMAs. As expected, they all exhibited good near infrared absorption and narrow band gap (Eopt g