D–π–A–π–D type benzothiadiazole–triphenylamine based small molecules containing cyano on the π-bridge for solution-processed organic solar cells with high open-circuit voltage

Abstract

Two novel D-π-A-π-D structured small molecules composed of benzothiadiazole and triphenylamine were designed and synthesized. with cyano on the π-bridge exhibited a deep HOMO energy level, resulting in an impressive V(OC) of up to 1.04 V with a PCE of 3.85%, while non-cyano substituted yielded a V(OC) of 0.94 V and a PCE of 1.99%.