Enhanced Performance in Cesium Tellurium Chlorine by Hafnium Alloying for X-Ray Computed Tomography Imaging

The term "light yield" (LY) refers to the ability of scintillator materials to convert high-energy radiation into visible light. A higher LY corresponds to improved energy and spatial resolution in detectors. The enhancement of scintillator material performance is a crucial aspect of their development. In this study, the Cs2TeCl6 (CTC) double perovskite microcrystals is synthesized, and the broadband yellow emission shows a high degree of matching with the Charge-coupled Device (CCD). However, the LY of CTC is poor for practical applications in X-ray imaging. The scintillation performance is significantly enhanced through hafnium alloying. The LY increased from approximate to 4167 to 38 523 photons/MeV, and the detection limit decreased from 948 to 258 nGy s-1. The underlying mechanism of Te4+ ions emission is systematically explored through density function theory (DFT) analysis, along with investigations into pressure-dependent photoluminescence, temperature-dependent photoluminescence, and low-temperature thermoluminescence. Furthermore, a flexible X-ray scintillator screen with an outstanding high spatial resolution of 15.9 lp mm-1 is successfully fabricated. This work not only represents a substantial advancement in the scintillation performance of Te4+ ions emission double perovskite microcrystals but also provides an effective strategy for the development of the next generation of halide scintillators. The high-efficiency Te4+ ions emission is realized in alloyed halide Cs2Hf0.95Te0.05Cl6 under UV light and X-ray. High-quality X-ray imaging is realized by Cs2Hf0.95Te0.05Cl6-PDMS flexible scintillator screen. image