Double‐Shell Encapsulation of Lead‐Free Tin Halide Perovskite for Self‐Powered Smart Windows

Abstract Luminescent solar concentrators (LSC) have the potential application in building integrated photovoltaic (BIPV). 0D tin‐based perovskites are a promising embedding phosphor in LSC due to the large Stokes shift and high photoluminescence quantum yield. But the instability and uncontrollable crystal growth are severe limiting their successful utilization in device fabrication. To tackle these issues, double‐shell encapsulated configurations are presented, soft ligands of hypophosphorous acid and hard‐shell of hollow mesoporous silica are simultaneously suppressing the oxidation of Sn 2+ and restricting crystal growth within nano‐matrix. The stable phosphor is subsequently embedded into LSC for harvesting solar energy and the resulting output power efficiently drives the combined electrochromic glass under natural light. These fabricated devices also offer the self‐adaptable switch on/off functionality to regulate light absorption with variable solar irradiation intensity in real time. This approach is anticipated to open new avenues for utilizing lead‐free perovskite nanomaterials in self‐powered smart windows for BIPV.