Synthesis of organo tin halide perovskites via simple aqueous acidic solution-based method

Organometal halide perovskites have been studied extensively during the last ten years for their interesting applications in solar cells and optoelectronics. One drawback of these materials is the presence of lead inside the compound, thus limiting their practical applications. Replacing lead with tin has been one of the implemented approaches for lead-free perovskites. In this paper, we report on the synthesis of organo tin mixed halide perovskites CH3NH3SnBrxCl3-x at room temperature in an aqueous acidic mixture between HCl and H3PO2 without the need of protecting perovskites against moisture. X-ray diffraction patterns show that the tin mixed halide perovskites adopt the trigonal phase. A detailed analysis of Raman scattering measurements has identified several low frequency Sn-Cl and Sn-Br modes of these perovskites. These results show that the high-quality CH3NH3SnBrxCl3-x crystals have been successfully synthesized by this aqueous solution-based method, demonstrating a low-cost approach to replace lead in organo metal halide perovskites for photovoltaic and optoelectronic applications.