Efficient Inverted CsPbI3 Solar Cells with Pb―S Contained Organosulfide-Halide Perovskite Heterojunction

Here robust Pb-S covalency is successfully incorporated into CsPbI3 heterojunction by introducing a new zwitterionic organosulfide-halide perovskite on top of CsPbI3. Cysteamine (CYS: +NH3(CH2)(2)S-) will react with PbCl2 and form a new 3D perovskite with much shallower fermi level on CsPbI3 surface, constructing an efficient CsPbI3/[CYS][PbCl2] heterojunction. As a result, interfacial energy loss can be significantly inhibited and device open-circuit voltage (Voc) is increased to over 1.20 V with champion efficiency of 20.38% in inverted CsPbI3 perovskite solar cells (PSCs). Besides, the intrinsic moisture and phase stability of [CYS][PbCl2] perovskite will effectively stabilize the CsPbI3 beneath owing to its robust Pb-S covalency. PSCs with [CYS][PbCl2] exhibit significantly improved stability, whether in moist air or under continuous maximum power point (MPP) tracking.