An Organic–Inorganic Tin Halide Perovskite with Over 2000‐Hour Emission Stability

Abstract Organic–inorganic tin (Sn)‐based halide perovskites have attracted special attention due to their outstanding photophysical properties and eco‐friendly nature. However, the instability of Sn‐based perovskites is still a pressing issue that needs to be addressed. Here, a new lead‐free hybrid Sn(IV) bromide hybrid (4‐APEA)₂SnBr₆ (4‐APEA: 2‐(4‐aminophenyl)ethylammonium) is synthesized with remarkable stability. This compound has strong electron–phonon coupling, resulting in excitons self‐trapping and broadband yellow emission with a photoluminescence peak at 566 nm. The bare (4‐APEA)₂SnBr₆ shows impressive emission stability in the air; maintains 90% of photoluminescence quantum yield under ultraviolet light irradiation over 2000 h (T₉₀ > 2000 h), representing the most stable halide hybrids. The excellent stability is profit from the stable valence state and few defect state densities. The findings show the promising prospect of environment‐friendly organic–inorganic halide perovskites and their usage in optoelectronic applications.