Terrylene Diimide-Based Middle-Low Bandgap Electron Acceptors for Organic Photovoltaics

摘要： Rylene diimides have evolved as the most investigated compounds among polycyclic aromatic hydrocarbons, due to their excellent absorption, fluorescence and outstanding electron-withdrawing ability. In this work, we present two A-D-A type electron acceptors based on terrylene diimide and investigate the impact of intramolecular nonbonding conformational locks on the molecular geometry, the solid packing arrangement as well as the photovoltaic performance. Detailed investigation demonstrates that the introduction of fluoride atoms facilitates the noncovalent interactions with sulfur elements on adjacent thiophene groups and therefore, more balanced charge transfer as well as suppressed bimolecular recombination prompt the JSC and FF, endowing the solar cells based on fluoride-substituted acceptor with a higher PCE up to 5.29%.