Turning Nonemissive CsPb₂Br₅ Crystals into High-Performance Scintillators through Alkali Metal Doping

Abstract

X-ray scintillators have utility in radiation detection, therapy, and imaging. Various materials, such as halide perovskites, organic illuminators, and metal clusters, have been developed to replace conventional scintillators due to their ease of fabrication, improved performance, and adaptability. However, they suffer from self-absorption, chemical instability, and weak X-ray stopping power. Addressing these limitations, we employ alkali metal doping to turn nonemissive CsPb 2 Br 5 into scintillators. Introducing alkali metal dopants causes lattice distortion and enhances electron−phonon coupling, which creates transient potential energy wells capable of trapping photogenerated or X-ray-generated electrons and holes to form self-trapped excitons. These self-trapped excitons undergo radiative recombination, resulting in a photoluminescence quantum yield of 55.92%. The CsPb 2 Br 5 -based X-ray scintillator offers strong X-ray stopping power, high resistance to self-absorption, and enhanced stability when exposed to the atmosphere, chemical solvents, and intense irradiation. It exhibits a detection limit of 162.3 nGy air s −1 and an imaging resolution of 21 lp mm −1 .

A NaBiF4:Gd/Tb nanoscintillator for high-resolution X-ray imaging

“…However, these traditional inorganic scintillators are typically confined to bulk crystals, and exhibit uncontrollable particle sizes, 15,16 non-uniform morphology, 17 non-tunable XEOL wavelength, 18,19 and limited conversion efficiency, hindering their practical utility. 20,21 As a result, it would be critical to investigate innovative methods for developing highly efficient and cost-effective scintillators 22,23 to overcome the aforementioned constraints and fulfil the rising needs of X-ray imaging technologies.…”