Systematic study on CsSnBr3 perovskite microcrystals: Chemical vapor deposition growth, structure, stability and optical properties

Although lead-based halide perovskites have promising applications in optoelectronic devices, these applications are limited by the toxicity of the materials. Therefore, it is necessary to develop lead-free all-inorganic substitute such as tin-based halide perovskites in spite of the enormous challenges in their controllable synthesis and stability. Here, we report the controlled growth of high quality CsSnBr3 microcrystals on SiO2/Si substrates by chemical vapor deposition method. The as-prepared products pre-dominantly show the morphology of triangle star and nail-like rod and the structure of cubic phase. The control of nucleation density and size of CsSnBr3 microcrystals has been realized by varying the growth temperature. The results of air-exposed samples explain the structural instability of the tin-based perovskites due to the production of SnO. The power and temperature dependent photoluminescence spectra reveal that CsSnBr3 microcrystals with different morphologies possess different exciton binding energies and produce different photoexcitation species due to the quantum confinement effect that changes the electron-hole effect.