Asymmetric Nonfused Ring Electron Acceptor Based on Benzotriazole Moiety for Efficient Organic Solar Cells

Nonfused ring electron acceptors (NFREAs) have received much attention due to their distinguished advantages such as simple chemical structure, facile synthesis, and low cost. Herein, three NFREAs with asymmetric and symmetric terminal groups, named CY101, CY102, and CY103, respectively, are designed and synthesized. The effect of terminal groups on the photophysical, electrochemical, and charge transport properties of the NFREAs is further investigated, providing insight to the relationships between the molecular structures and properties of NFREAs. It is found that the asymmetric NFREA CY102-based organic solar cells (OSCs) can yield a power conversion efficiency of 11.30%, which is higher than those of the symmetric CY101-based OSCs (10.20%) and CY103-based OSCs (8.99%). These results indicate that the asymmetric design strategy can be introduced into NFREAs to engage the high-performance OSCs.