High-Efficiency Binary and Ternary Organic Solar Cells Based on Novel Nonfused-Ring Electron Acceptors.

In this study, we designed and synthesized three nonfused-ring electron acceptors (2TT, 2TT-C6-F, and 2TT-C11-F) with the same steric hindrance groups (2,4,6-tripropylbenzene) and explored the impact of electron-withdrawing and lateral alkyl side chains on the performance of binary and ternary organic solar cells (OSCs). For the binary OSCs, 2TT-C11-F with IC-2F terminal groups and lateral undecyl side chains displayed a red shifted absorption spectrum and suitable energy levels, and the corresponding blend film exhibited appropriate phase separation and crystallinity. Thus, binary OSCs based on 2TT-C11-F achieved an impressive power conversion efficiency of 13.03%, much higher than the efficiencies of those based on 2TT (9.68%) and 2TT-C6-F (12.11%). In the ternary OSCs, 2TT with CC terminal groups and lateral hexyl side chains exhibited complementary absorption and cascaded energy levels with a host binary system (D18:BTP-eC9-4F). Hence, the ternary OSCs based on 2TT achieved a remarkable efficiency of 19.39%, ranking among the highest reported values. Our research yielded comprehensive 2TT-series nonfused-ring electron acceptors, demonstarting their great potential for the fabrication of high-performance binary and ternary OSCs. This article is protected by copyright. All rights reserved.