Fabrication of MASnI(3) and MASn(x)Pb((1-x))I(3) Thin Films by Conversion from SnS Thin Film

Methylammonium lead halide (MASnI(3)), an organic-inorganic hybrid perovskite material, is promising as light absorbing materials of solar cells. Nevertheless, necessity of reducing Pb contents in the perovskite materials is increasing due to the toxicity of Pb. Recently, tin-lead mixed perovskite materials have been studied intensively, by dissolving Sn and Pb sources simultaneously in one precursor solution. Here, for the first time, we report a two-step method to synthesize MASnI(3) and MASn(x)Pb((1-x))I(3) films. The films were prepared via spin-coating MAI or MASnI(3 )precursors on as-prepared SnS thin films. Crystal structures, phases, surface chemical states, and morphologies of the MASnI(3) and MASn(x)Pb((1-x))I(3) films were investigated. Our two-step method is expected to be used not only for Sn based perovskites but also for diverse compositions of perovskite materials.