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

Ternary organic solar cells based on polymer donor PBDB-T, non-fullerene acceptor IDTCN-S and fullerene acceptor PC 71 BM can achieve enhanced charge transfer and improved the ternary blend film morphology. [Display omitted] • The enhanced charge transfer can be achieved via ternary blend strategy. • PC 71 BM as the third component can also effectively improve the blend morphology. • The ternary devices demonstrate an elevated PCE compared with two binary devices. 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 PC 71 BM, which possess complementary absorption spectra. The introduction of PC 71 BM 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 PC 71 BM 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 PC 71 BM is the efficiently third component for the construction of high-efficiency ternary OSCs. [ABSTRACT FROM AUTHOR]