Incorporating Rare‐Earth Terbium(III) Ions into Cs2AgInCl6:Bi Nanocrystals toward Tunable Photoluminescence

Abstract The incorporation of impurity ions or doping is a promising method for controlling the electronic and optical properties and the structural stability of halide perovskite nanocrystals (NCs). Herein, we establish relationships between rare‐earth ions doping and intrinsic emission of lead‐free double perovskite Cs 2 AgInCl 6 NCs to impart and tune the optical performances in the visible light region. Tb 3+ ions were incorporated into Cs 2 AgInCl 6 NCs and occupied In 3+ sites as verified by both crystallographic analyses and first‐principles calculations. Trace amounts of Bi doping endowed the characteristic emission ( 5 D 4 → 7 F 6‐3 ) of Tb 3+ ions with a new excitation peak at 368 nm rather than the single characteristic excitation at 290 nm of Tb 3+ . By controlling Tb 3+ ions concentration, the emission colors of Bi‐doped Cs 2 Ag(In 1− x Tb x )Cl 6 NCs could be continuously tuned from green to orange, through the efficient energy‐transfer channel from self‐trapped excitons to Tb 3+ ions. Our study provides the salient features of the material design of lead‐free perovskite NCs and to expand their luminescence applications.