Excitation‐Dependent Emission in All‐Inorganic Lead‐Free Cs2ScCl5·H2O Perovskite Crystals

Abstract Low‐dimensional lead‐free metal halides have recently attracted a great deal of attention for their unique photoluminescence properties. In this work, a new all‐inorganic zero‐dimensional (0D) rare‐earth perovskite, namely Cs 2 ScCl 5 ·H 2 O is reported. The 0D crystal exhibits a rare phenomenon of excitation‐wavelength dependent emission from blue‐green to white to yellow at room temperature. Spectroscopic characterizations indicate the tunable emission is originated from two distinct self‐trapped exciton states. In addition, the yellow emission quantum yield can be enhanced from 1.2% to ≈100% by doping Sb 3+ ions into the crystal. The work not only presents a new all‐inorganic semiconductor with tunable emission colors, but also provides a design strategy for developing nontoxic and high‐performance light‐emitting materials.