The air and thermal stabilities of lead-free perovskite variant Cs2SnI6 powder

Cs2SnI6, as an inorganic lead-free perovskite variant, is regarded as a more environment friendly photovoltaic material than methylammonium lead iodide perovskite. However, its air and thermal stabilities still remain unclear. In this paper, Cs2SnI6 powders were synthesized via a chemical bath deposition method. The crystalline phases, morphologies, and vibrational properties were investigated. Moreover, its phase and morphology can retain in air with high relative humidity over a week even a month. The thermal stability measurements indicate Cs2SnI6 is stable up to 270 °C and then decomposes to CsI and SnI4. These results should pave the way for further application of Cs2SnI6 for more stable solar cells.