Space-Confined Chemical Vapor Deposition Synthesis of All-Inorganic CsSnI₃ Perovskite Nanosheets

All-inorganic two-dimensional (2D) CsSnI3 nanosheets exhibit reduced biotoxicity, high mobility, and suitable band gap, making them highly promising for nanoelectronic or optoelectronic applications. However, the synthesis of 2D CsSnI3 nanosheets remains challenging. In this study, 2D CsSnI3 nanosheets were successfully synthesized by using a space-confined chemical vapor deposition (CVD) method for the first time. The average thickness and lateral size of 2D CsSnI3 nanosheets were well-controlled by adjusting the gap distance within the confined space and the growth temperature. This approach also facilitated in situ construction of CsSnI3-based vertical heterostructures by directly growing CsSnI3 nanosheets on the surface of target WSe2. The space-confined CVD growth of lead-free perovskite nanosheets will provide more options for the development of low-dimensional perovskite-based optoelectronic devices.