高性能非稠环受体分子改性的理论研究

Small molecule non-fused ring acceptors (SM-NFRA) constitute an important branch in the field of non-fullerene acceptors and have gradually garnered attention in organic photovoltaic (OPV) research in recent years. Currently, OPV cells based on SM-NFRA have achieved a power conversion efficiency (PCE) of up to 19%. However, research on high-efficiency SM-NFRA is still relatively scarce, and the PCE of OPV cells based on SM-NFRA remains lower than that of fused ring acceptors. Therefore, this study focuses on a high-performance SM-NFRA, namely 2BTH-2F-C2, and designs six new derivatives of 2BTH-2F-C2 through halogen substitution at the terminal groups and substitution of the central core element. Using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods, the geometric structures, ground-state, and excited-state properties of these molecules were systematically explored. The research results indicate that the modified molecules, particularly 2BTT4O-2F-C2, exhibit superior performance in multiple aspects compared to the original molecule. Specifically, 2BTT4O-2F-C2 demonstrates better planarity, a smaller exciton binding energy, a larger average electrostatic potential, a redshifted absorption spectrum, and stronger absorption in the visible light region. These findings provide insights for the structural design and performance optimization of non-fused ring acceptor molecules.????