Influence of A-Site Cation Composition on the Electronic Properties of Halide Tin Perovskites

Tin halide perovskites are interesting as a potential replacement for lead-based perovskites in various device technologies. However, their charge transport properties have received limited attention compared to those of their lead-based counterparts. In particular, the effect of the A-site cation on the electronic properties of tin perovskites warrants further attention to design efficient material systems for various applications beyond photovoltaics. In this study, we explore the relationship between the A-site composition and electronic properties in tin perovskites (ASnI 3 ) by leveraging the composition tunability of halide perovskites. We investigate the effect of prototypical A-site cations such as formamidinium (FA), methylammonium (MA), and cesium (Cs) and their binary combinations on structure, morphology, and electronic properties of ASnI 3 . Our findings reveal that the MA–Cs combination offers the highest electrical conductivity owing to simultaneously enhanced mobility and carrier density compared to single-cation compositions based on MA and Cs resulting in a thermoelectric power factor of ∼162 μW m –1 K –2 . The library of properties generated for Sn perovskites in this work will be valuable for their further development as an electronic material.