Gamma-Ray Irradiation Stability of Zero-Dimensional Cs₃Cu₂I₅ Metal Halide Scintillator Single Crystals

Zero-dimensional Cs₃Cu₂I₅ is one of the most promising metal halide scintillators due to its large Stokes shift, photoluminescence quantum yields, freedom from toxic elements, and excellent energy spectrum resolution. To unlock the full potential of Cs₃Cu₂I₅ as an effective alternative to traditional scintillators for gamma-ray detection, the irradiation stability of Cs₃Cu₂I₅ single crystals under ⁶⁰Co gamma rays with a maximum accumulated dose of 800 krad was explored. Although the luminescence mechanism remained unchanged after irradiation, the optical properties of Cs₃Cu₂I₅ single crystals demonstrated a dose-dependent change at low accumulated doses (<600 krad). However, a further increase in the accumulated dose did not lead to more severe degradation and even slight performance recovery occurred. Electron paramagnetic resonance and theoretical calculation results revealed that the irradiation-induced Cs⁺-related Frenkel defects contribute to performance degradation. These results shed light on the microscopic mechanism of gamma-ray irradiation damage of Cs₃Cu₂I₅ single crystal and provide guidance to their real application.