High Thermal Stability of Copper-Based Perovskite Scintillators for High-Temperature X‑ray Detection

High-temperature scintillation detectors play a significant role in oil exploration. However, traditional scintillators have limited ability to meet the requirements of practical applications owing to their low thermal stability. In this study, we designed and developed a one-dimensional (1D) Cs5Cu3Cl6I2 scintillator with high thermal stability. In addition, by preparing Cs5Cu3Cl7I, we proved that the Cs5Cu3Cl6I2 scintillator exhibits high thermal stability because the bridges linking the structural units in the 1D chain structure are only formed by I– ions, which improve their structural rigidity. The scintillator has a high steady-state light yield (59,700 photons MeV–1) and exhibits the highest spatial resolution for powder-based scintillation screens (18 lp mm–1) after cyclic treatment within the temperature range of 298–423 K. The Cs5Cu3Cl6I2 scintillator allows the visualization of alloy melting, indicating that it has significant potential for application in high-temperature environments. This study provides a new perspective toward the design of scintillators with high thermal stability.