First-Principles Screening of Lead-Free Methylammonium Metal Iodine Perovskites for Photovoltaic Application

Although organo-halide lead perovskite solar cells have achieved outstanding photovoltaic performance in recent years, environmental concern about lead pollutant limits its large-scale commercialization. To address lead-free organo-halide perovskite materials, here we report first-principles screening of different perovskite materials MAXI(3) with consideration of all possible (27 in total) divalent metal ions. Ten kinds of perovskite structures are obtained with a nonzero bandgap, and the others are metallic. Among them, five kinds of perovskite materials (MAXI(3): X = Pb, Sn, Ge, Cd, Be) have appropriate bandgaps as the light-absorbing material in solar cells, in which MACdI(3) and MABeI(3) are reported for the first time. Various corresponding experiments have been carried out to confirm our theoretical predictions