Effects of Sc³⁺ and Y³⁺ codoping on luminescence and scintillation properties of LaBr₃:Ce single crystals

In this work, the effects of Sc and Y codoping on the luminescence and scintillation properties of LaBr₃:Ce single crystals were systematically studied. LaBr₃:Ce single crystals with a diameter of 7 mm codoped with different Sc and Y concentrations were grown by the vertical Bridgman method. It was found the incorporation of Sc codoping does not alter the luminescence mechanism and exhibits limited effects on light yield and energy resolution. In contrast, with the introduction of Y codopant, the LaBr₃:Ce single crystals exhibit coloration. In addition to the feature Ce³⁺ 5d-4f emission, Y codoped LaBr₃:Ce has a defect-related emission ranging from 450 nm to 800 nm under both photoluminescence and X-ray excitation. Moreover, Y codoping introduces a slow scintillation decay component of 260 ns and an enhanced X-ray afterglow level. Both light yield and energy resolution of LaBr₃:Ce were significantly deteriorated after Y codoping.