All-Inorganic Zero-Dimensional Sb3+-Doped Rb2ScCl5(H2O) Perovskite Single Crystals: Efficient Self-Trapped Exciton Emission and X‑ray Detection

Zero-dimensional (0D) halide perovskites have attracted extensive attention for their potential applications in solid-state lighting and X-ray detection due to their fascinating optoelectronic properties and convenient solution processability. Herein, we report the synthesis and photophysical properties of high-quality Sb3+-doped 0D Rb2ScCl5(H2O) perovskite single crystals. The pristine crystals exhibit weak yellow self-trapped exciton (STE) emission peaking at 632 nm. The emission quantum yield can be dramatically enhanced from less than 1% to about 53% via Sb3+ doping. Spectroscopic characterizations indicate that the photoluminescence enhancement is a result of the efficient energy transfer from Sb3+ to the emissive STEs. Additionally, 0.2%Sb3+:Rb2ScCl5(H2O) single crystals exhibit potential application in direct X-ray detection with a high sensitivity of 58.5 μC Gy–1 cm–2.