Enhancing persistent radioluminescence in perovskite scintillators through trap defect modulation

Abstract

Flexible X-ray sensors utilizing persistent radioluminescence scintillators have garnered considerable interest in medical imaging and industrial non-destructive testing. However, persistent radioluminescence in scintillators is typically generated by releasing stored electrons from deep trap defects at high temperatures, significantly limiting X-ray imaging sensitivity. The requirement of high temperatures for thermally-stimulated radioluminescence to erase harmful X-ray memory also impedes the repeated use of flexible sensors. Here we report high-efficiency persistent radioluminescence at room temperature by modulating the depth and density distribution of trap defects through codoping with Mn²⁺ and Sb³⁺ in CsCdCl₃ scintillators. This results in a 20-fold increase in radioluminescence afterglow at room temperature, leading to significantly enhanced X-ray imaging sensitivity and facile erasure of harmful X-ray memory at relatively low temperatures for repeated use of the flexible sensors. Furthermore, the as-synthesized scintillators exhibit excellent resistance to thermal quenching, maintaining 96.63% radioluminescence efficiency at 493 K, and commendable stability concerning humidity and solvent exposure. Additionally, we fabricated flexible X-ray imaging sensors achieving high-resolution (20.0 lp mm⁻¹) imaging of irregulate objects at room temperature using CsCdCl₃:5%Mn²⁺/0.1%Sb³⁺ crystals. These findings provide valuable insights into ion doping for the regulation of trap defects in scintillators, motivating the development of high-resolution time-lapse X-ray imaging sensors.