All-Inorganic Zero-Dimensional Sb 3+ -Doped Rb 2 ScCl 5 (H 2 O) 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 Sb 3+ -doped 0D Rb 2 ScCl 5 (H 2 O) 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 Sb 3+ doping. Spectroscopic characterizations indicate that the photoluminescence enhancement is a result of the efficient energy transfer from Sb 3+ to the emissive STEs. Additionally, 0.2%Sb 3+ :Rb 2 ScCl 5 (H 2 O) single crystals exhibit potential application in direct X-ray detection with a high sensitivity of 58.5 μC Gy -1 cm -2 .