Non-Hygroscopic, Self-Absorption Free, and Efficient 1D CsCu₂I₃ Perovskite Single Crystal for Radiation Detection

A novel all-inorganic CsCu₂I₃ single-crystalline perovskite as a nonhygroscopic and efficient X-ray and γ-ray scintillator is described herein. It is featured by a one-dimensional (1D) perovskite structure with an orthorhombic system and a space group of Cmcm. The CsCu₂I₃ crystal emits yellow light peaking at 570 nm originated from strongly localized 1D exciton emission. It appears self-absorption free because of the large Stokes shift of 1.54 eV. The photophysics process of the self-trapped exciton was studied using temperature dependent photoluminescene spectra and decay kinetics measurements. The CsCu₂I₃ crystal exhibits an extremely low afterglow level of 0.008% at 10 ms under X-ray excitation. Under ¹³⁷Cs γ-ray irradiation, its light yield is 16 000 photons/MeV with an energy resolution of 7.8% at 662 keV.