Synthesis, Characterization, and Solar Cell Applications of a Non-fused-ring Electron Acceptor Based on Vinylene-bridged Difluorobenzothiadiazole

A new non -fused-ring electron acceptor (NREA), BE4T based on vinylene-bridged difluorobenzothiadiazole (FBTzE) has been synthesized and characterized. BE4T was found to be suitable for high-performance OPVs due to its strong absorp-tion around 600-800 nm and low-lying HOMO/LUMO energy levels. However, BE4T-based cells showed a low PCE of 1.05% owing to the formation of highly ordered edge-on and large phase separation structure in the blended films.