Low-Temperature-Processed Perovskite Solar Cells Fabricated from Presynthesized CsFAPbI₃ Powder

Investigating the methylammonium (MA) and bromide (Br)-free perovskite structure is paramount to reduce thermal diffusion and phase segregation, which have plagued the rapid development of perovskite solar cells (PSCs). Such engineered compositions are intrinsically stable and compatible with single- and multi-junction solar cells. We demonstrate a δ-phase-free formamidinium-based solar cells, derived from a powder perovskite precursor Cs0.1FA0.9PbI3 fabricated at a moderate temperature of 80 °C, to yield a competitive performance >17% with negligible hysteresis. Importantly, these fabricated PSCs show enhanced stability and efficiency over the conventional FAPbI3 which demands high-temperature (150 °C) processing for solar cell fabrication. We put forward an innovative approach for substantial materials synthesis, which can be effectively processable at low temperatures.