Effect of intermolecular interaction with phenothiazine core on inverted organic photovoltaics by using different acceptor moiety

Abstract Six novel small molecules containing phenothiazine as the core moiety of p-type materials were synthesized in combination with PC 61 BM or PC 71 BM as n-type materials for bulk heterojunction organic photovoltaic (OPV) cells. Phenothiazine was used as donor building blocks to construct acceptor–donor–acceptor (A–D–A) and A–D–D–A small molecule. We investigated the relationship between the molecular structures, optoelectronic and thermal properties, and their blend film morphologies for OPV applications. We further studied their photophysical properties using a time-dependent density functional theory model and the B3LYP functional. A solution-processed OPV employing PT2-DE combined with the electron acceptor PC 61 BM and additive DIO achieved optimal device performance, with a short-circuit current of 6.3 mA cm −2 , an open-circuit voltage of 770 mV, a fill factor of 0.55, and a corresponding overall conversion efficiency of 2.64%. To the best of our knowledge, this is the best-reported performance of a phenothiazine derivative for OPV application.