Tb 3+ Single‐Doped High‐Entropy Glass Scintillator With Improved Thermal Stability for High‐Temperature X‐Ray Imaging

High‐entropy materials stand out owing to their unique entropy‐driven structural stabilization and high‐degree lattice disorder. As a representative subclass, high‐entropy luminescent materials gain wide attention for outstanding thermal tolerance, matching high‐temperature demands of phosphors and scintillators. Nevertheless, high‐entropy glass scintillators are barely explored and deserved in‐depth research. In this work, multi‐cation glass systems with entropies of 1.57 R –1.63 R were designed via mixing entropy, adopting a matrix composition of 20Al 2 O 3 ‐50SiO 2 ‐10NaF‐5CaF 2 ‐5SrF 2 ‐5BaF 2 ‐5MgF 2 . An optimized high‐entropy glass scintillator was fabricated with 8 mol% Tb 3+ doping. It integrates excellent optical performances, with high transmittance of over 88% and superior radioluminescence (RL) intensity of 262% of that of commercial Bi 4 Ge 3 O 12 . Thermoluminescence analysis results confirm that the high‐entropy engineering induces deeper trap and higher trap density. Compared with four reference glass materials, the high‐entropy specimen exhibits remarkably improved thermal stability of photoluminescence (PL) and RL. Specifically, at 573 K, its PL and RL intensities achieve 93.4% and 143% compared to that at room temperature. Owing to anti‐thermal‐quenching in RL, a spatial resolution of 25 lp/mm for x‐ray imaging is realized at elevated temperature. This work confirms the effectiveness of high‐entropy engineering based on mixing entropy to design high‐performance, thermally robust glass scintillators for high‐temperature x‐ray imaging.