All-Inorganic Copper Halide as a Stable and Self-Absorption-Free X-ray Scintillator

Lead halide perovskites have recently shown great potential as X-ray scintillators; however, the toxicity of the lead element seriously restricts their applications. Herein we report a new lead-free and self-absorption-free scintillator based on Rb₂CuCl₃ metal halide. The Rb₂CuCl₃ exhibits a near-unity photoluminescence quantum yield (99.4%) as well as a long photoluminescence lifetime (11.3 μs). Furthermore, Rb₂CuCl₃ demonstrates an appreciable light yield of 16 600 photons per megaelectronvolt and a large scintillation response with a linear range from 48.6 nGy_air s^-1 to 15.7 μGy_air s^-1. Notably, the detection limit is as low as 88.5 nGy_air s^-1, enabling a reduced radiation dose to the human body when a medical and security check is conducted. In addition, Rb₂CuCl₃ exhibits good stability against the atmosphere, continuous ultraviolet light, as well as X-ray irradiation. The combination of the decent scintillation performance, low toxicity and good stability suggests the Rb₂CuCl₃ could be a possible promising X-ray scintillator.