Composition engineering of Tb3-xGdxAl5-yGayO12:Ce single crystals and their luminescent, scintillation and photoconversion properties

Abstract The luminescence, scintillation, and photoconversion properties of the single crystals of Ce3+ doped Tb3−xGdxAl5-yGayO12 (х = 0–1.5; у = 2–2.5) mixed garnets, grown by the micro-pulling-down (μ-PD) method, are investigated as a function of the Tb/Gd ratio with the aim of development of phosphor-convertors of white LED and scintillators. The partial Tb3+ substitution by Gd3+ cations leads to the suitable change of the crystal field splitting of the 5d energy levels of Ce3 ions due to different sizes of the Gd3+ and Tb3+ cations. For this reason, the cation engineering enables to improve the luminescence and scintillation characteristics of Tb3−xGdxAl3-2.5Ga2-2.5O12 crystals due to increasing the efficiency of Gd3+→ Tb3+→ Ce3+ cascade energy transfer observed in these solid solutions. We have shown that from all the crystals under study, the Tb3-xGdxAl2.5Ga2.5O12:Ce (х = 1–1.5) crystal is the best promising candidate for the photoconversion and scintillation applications.