Developing new perovskite-based scintillator employing an overlooked luminescence phenomenon

Abstract

We have studied luminescence and scintillation properties of LaAlO₃ crystal triply codoped with 0.1%Ce, 0.1%Cr and 0.1% Mg. Such a doping invoked Ce-terminated Cr emission, a phenomenon observed earlier in other materials, but long time overlooked. The emission appeared at 418 nm under excitation into Ce³⁺ 4f-5d absorption bands. It is worth mentioning that such an observation was made for material where no Ce-related luminescence can be observed at all. The possible luminescence mechanism is discussed together with promising characteristics such as photoluminescence decay time around 45 ns and an overall scintillation efficiency just slightly inferior to that of BGO. However, the significant afterglow deteriorates the practical scintillation parameters. Despite that, we do believe that the described codoping strategy and deeper understanding of the luminescence and afterglow mechanisms can lead to development of new luminescence and scintillation materials where Ce³⁺ 5d-4f luminescence cannot usually take place, but the Ce-terminated Cr-emission can be exploited. There is also considerable room for further material optimization by the dopant concentration tuning.