Highly Efficient Blue‐Emitting Bi‐Doped Cs2SnCl6 Perovskite Variant: Photoluminescence Induced by Impurity Doping

Abstract Lead halide perovskites show excellent optoelectronic properties but are unsatisfactory in terms of stability and toxicity. Herein, bismuth (Bi)‐doped lead‐free inorganic perovskites Cs 2 SnCl 6 :Bi are reported as blue emissive phosphors. Upon Bi doping, the originally nonluminous Cs 2 SnCl 6 exhibits a highly efficient deep‐blue emission at 455 nm, with a Stokes shift of 106 nm and a high photoluminescence quantum yield (PLQY) close to 80%. Hybrid density functional theory calculations suggest the preferred formation of Bi Sn +V Cl defect complex, which is believed to be responsible for the optical absorption and the associated blue emission. The Cs 2 SnCl 6 :Bi also shows impressive thermal and water stability due to its inorganic nature and the formation of protective BiOCl layer. White light‐emitting diodes (LEDs) are constructed using Cs 2 SnCl 6 :Bi and commercial yellow phosphors combined with commercial UV LED chips, giving the Commission Internationale de I'Eclairage (CIE) color coordinates of (0.36, 0.37). This work represents a significant step toward the realization of highly efficient, stable, and environmentally benign next‐generation solid‐state lighting.