Employing fullerene acceptor as the third component to enhance charge transfer for high-efficiency ternary organic solar cells

Abstract

Ternary organic solar cells (OSCs) based on one donor/one non-fullerene acceptor/one fullerene acceptor have been proven to be a promising method to boost photovoltaic performance. Herein, we report high-efficiency ternary OSCs fabricated with polymer donor PBDB-T, non-fullerene acceptor IDTCN-S and fullerene acceptor PC71BM, which possess complementary absorption spectra. The introduction of PC71BM as the third component into PBDB-T:IDTCN-S binary system can form cascade energy level alignment, which can facilitate charge transfer in the ternary blend films. Meanwhile, the addition of PC71BM also improve the ternary thin film morphology. As a result, ternary solar cells greatly boost the photovoltaic performance from 10.86% (PBDB-T:IDTCN-S) to 12.03%. Our research indicates that fullerene acceptor PC71BM is the efficiently third component for the construction of high-efficiency ternary OSCs.