Efficient Fused‐Ring Extension of A–D–A‐Type Non‐Fullerene Acceptors by a Symmetric Replicating Core Unit Strategy
Tian Xia, Chao Li, Hwa Sook Ryu, Jing Guo, Jie Min, Han Young Woo, Yanming Sun
Abstract
The extension of fused aromatic ring core structures is beneficial for enhancing intramolecular charge transfer and effective π conjugation in A-D-A-type (A=acceptor; D=donor) non-fullerene acceptors (NFAs). In this work, a novel strategy involving the extension of a fused-ring core by symmetrically replicating the core unit has been developed, and a novel symmetric fused-12-ring NFA, LC81, has been synthesized. When paired with the wide-bandgap polymer donor PBT1-C, the corresponding organic solar cells (OSCs) showed a high power conversion efficiency of 12.71 %, much higher than that of the device based on the reference NFA, TPTT-4F. Moreover, the LC81-based OSC displayed a lower energy loss and a better ambient stability than the TPTT-4F-based device. Our results indicate that the extension of the fused-ring core by the symmetric replicating core unit strategy is an effective approach to promoting the photovoltaic characteristics of A-D-A-type NFAs.