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.