Pyran-annulated perylene diimide derivatives as non-fullerene acceptors for high performance organic solar cells

There has been growing interest in the effectual strategy of constructing non-fullerene acceptors for organic solar cells that may overcome the defect of traditional fullerene-based acceptors. Herein, two novel push-pull (acceptor-donor-acceptor) type small-molecule acceptors, that is, TPA-PDI₂ and TPA-PDI₃, with triphenylamine (TPA) as the core unit and pyran-annulated perylene diimides (Py-PDIs) as peripheral groups are designed and synthesized for non-fullerene organic solar cells (OSCs). After device optimization, OSCs based on TPA-PDI₃ demonstrate good device performance with a power conversion efficiency (PCE) as high as 5.84%, surpassing the TPA-PDI₂-based counterparts fabricated under identical conditions (1.314% PCE). The high efficiency for TPA-PDI₃ can be attributed to the complementary absorption spectra with the donor material (PBDB-T), balanced carrier transport and favorable morphologies. To the best of our knowledge, this PCE of 5.84% is among the highest values based on ethynyl-functionalized TPA-shaped non-fullerene acceptors so far.