Co-treatment of an inorganic additive SnF2 and an organic additive P(VDF-TrFE) for improving the performances of MASnBr3 films

Abstract

Non-toxic tin (Sn)-based perovskite is one of the most promising substitutes for toxic lead (Pb)-based perovskite. However, it is difficult to prepare well due to its instability and self-oxidation. In this study, co-adding suitable inorganic tin (II) fluoride (SnF2) and organic poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] in the Sn-based precursor solution was applied for the first time to obtain the high-quality methylammonium tin bromide (MASnBr3) perovskite film. The structural, morphological, and optical analyses discussed in this article indicate that simply adding inorganic SnF2 is insufficient to obtain MASnBr3 perovskite films with high crystallinity, uniform surface, and good optical properties. However, the SnF2 and P(VDF-TrFE) co-additives help to cause a significant decrease in morphological defects, an increase in absorption, and an enhancement in photoluminescence (PL). The X-ray diffraction (XRD) peak positions do not differ regardless of the type of additives, but the peak intensities are changed depending on the amount of the additives. It is exciting that the device fabricated using the co-added MASnBr3 perovskite films has an increased current density and a lower turn-on voltage.