Defect engineering in Mg²⁺ co-doped LuAG:Ce ceramics: Towards ultrahigh fast scintillation proportion

A slow scintillation component due to charge carrier capture at point defects is a serious issue in scintillator materials. Therefore, the fabrication of scintillators with a high proportion of fast components in the scintillation response is of great interest to material scientists. By applying the defect engineering strategy in advanced optical Lu₃Al₅O₁₂:Ce,Mg (LuAG:Ce,Mg) ceramics, an ultrahigh fast scintillation proportion can be achieved with a slight loss of fast scintillation light. Moreover, low-temperature thermoluminescence (TSL) investigations revealed that the intensities of all the TSL peaks decreased in the Mg²⁺-codoped samples. The slight loss of fast scintillation light observed was explained by density functional theory (DFT) calculations. The effect of {Ce³⁺–Mg²⁻} pairs on emission quenching was compared with that of {Ce³⁺–Ca²⁻} pairs. As a consequence, the 0.3 at% Mg²⁺-codoped ceramic sample has an LY_0.5µs/LY_10µs ratio of 99.8%, which is better than those reported for isostructural ceramics and single crystals. We conclude with a discussion of the role of Mg²⁺ co-doping and future research directions concerning other oxide scintillators.