A diketopyrrolopyrrole-based nonfullerene acceptor for organic solar cells with a high open-circuit voltage of 1.17？V

A new nonfullerene electron acceptor, BP(DPPB)4, with a biphenyl core and four diketopyrrolopyrrole (DPP) arms is synthesized. The molecular geometries, energy levels, optical properties, and photovoltaic properties of the acceptor are systematically studied. The relationship between thermal annealing temperature and morphology formation is discussed. Poly(3-hexylthiophene) is chosen as the electron donor material because of its complementary absorption profile and matched energy levels. The optimized organic solar cells can provide a power conversion efficiency of 1.43% with a high open-circuit voltage (Voc) of 1.17？V after thermal annealing at 120？°C for 10？min