posted on 2024-01-23, 13:04authored byJian Qiu, He Zhao, Zhen Mu, Jiaye Chen, Hao Gu, Chang Gu, Guichuan Xing, Xian Qin, Xiaogang Liu
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 CsPb2Br5 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 CsPb2Br5-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 nGyair s–1 and an imaging resolution of 21 lp mm–1.