Porphyrin Acceptors with Two Perylene Diimide Dimers for Organic Solar Cells

Three small‐molecule acceptors (Por‐PDI, TEHPor‐PDI, and BBOPor‐PDI) with different side chains were synthesized by using a porphyrin core as the electron‐donating unit and connecting electron‐withdrawing perylene diimide dimers via acetylene bridges. The bulk heterojunction organic solar cells based on the three acceptors and a polymer donor provided power conversion efficiencies (PCEs) of 3.68–5.21 % when the active layers were fabricated with pyridine additives. Though the synthesis of Por‐PDI is easier with fewer reaction steps and higher yields, the devices based on Por‐PDI showed the best performance with a PCE of 5.21 %. The more ordered intermolecular packing due to the reduced steric hindrance at the porphyrin core of Por‐PDI could contribute to the more balanced hole/electron mobilities, higher maximum charge generation rate, and less bimolecular recombination in Por‐PDI devices, which are beneficial for the higher PCE. Porphyrin acceptors: Three porphyrin acceptors with different side chains at the porphyrin core are synthesized by two connecting perylene diimide dimers or the bulk heterojunction organic solar cells, which provide power conversion efficiencies of 3.68–5.21 %. The devices based on the acceptor without any side chains at the porphyrin core show the best performance, which is ascribed to the more ordered intermolecular packing.