Double Perovskite Scintillators Enabled by Co‐Doped Trap Regulation for Thermally Enhanced X‐Ray Imaging

Abstract Scintillation materials play a significant role in the exploration of extreme space environments and high‐energy physics. Nevertheless, due to the prevalence of thermal quenching, most traditional scintillators are not capable of stable X‐ray imaging at high‐temperature working mode. In this work, Ce 3+ and Tb 3+ ions are successfully co‐doped into Cs 2 NaGdCl 6 double perovskites (DPs) via a solvothermal method, exhibiting unusual thermally enhanced scintillation performance. Specifically, the radioluminescence intensity of Cs 2 NaGdCl 6 :Tb 3+ /Ce 3+ increases with temperature to achieve a large intensity ratio of 3.67 from 80 to 500 K. Interestingly, the introduction of co‐doped ions brings the dramatic increase of thermoluminescence intensity, demonstrating that an increased number of deep trap results in the suppression of the thermal quenching. At the same time, the extra occurrence of deep traps can be traced to localized octahedral distortions around the dopant ions. Moreover, a flexible DP‐based scintillation film is fabricated by a direct coating method, showing thermally enhanced X‐ray imaging. Ultra‐stable X‐ray imaging performance over 5 h is realized under a high temperature of 380 K by the scintillation film. The results provide a trap regulation strategy for exploring novel high‐performance and stable scintillators at high temperatures.