Leveraging structural rigidity for thermal robust scintillation in rare-earth halide perovskites

High-temperature scintillators are critical components for X-ray imaging technique used in extreme environments such as oil well-logging, nuclear reactors and industrial inspections. Cu and Mn-based perovskites have high brightness but suffer from severe thermal quenching. In contrast, rare-earth based perovskites are candidates of high-temperature scintillators. However, their development is hindered by the absence of studying the relationship between structural rigidity and property. Herein, we find that rare-earth-doped 3D Cs 2 NaLuCl 6 and 0D Cs 3 LuCl 6 perovskites have thermally-stable emission resulting from their high Debye temperature exceeding 200 K and thermally-stable energy transfer efficiency. We also observe that Tb 3+ -green emission and Ce 3+ /Sm 3+ -red emission have brighter X-ray images than Ce 3+ -UV emission due to their camera-matched spectral emissions. The 3D perovskite has low structural rigidity and strong electron−phonon coupling, and the scintillator achieves a high emission intensity and slight thermal quenching. In contrast, the 0D perovskite has higher structural rigidity and weaker electron−phonon coupling, and the scintillator exhibits a lower emission intensity and pronounced anti-thermal-quenching. The findings provide insights into bolstering the structural rigidity of Lu-halide perovskites in achieving thermally-stable luminescence for high-temperature scintillators, and prompting efforts to utilize the emission color of scintillators. The structure-property relationship, including structural rigidity, Debye temperature, crystal hardness, electron−phonon coupling, RL intensity and thermal stability in 3D and 0D Lu-based perovskites is established. The 3D perovskite with low structural rigidity exhibits strong emission and undergoes slight thermal quenching. In contrast, the 0D perovskite with higher structural rigidity shows weaker emission and pronounced anti-thermal-quenching. Both 3D and 0D perovskite scintillators perform excellent X-ray imaging at the high temperature.