Tuning the persistent luminescence property of a Y3Al2Ga3O12:Ce3+,Yb3+ phosphor by controlling the intrinsic oxygen vacancy concentration.

Abstract

Oxygen vacancies (VO), acting as electron traps, have a significant impact on the persistent luminescence (PersL) property of persistent phosphors. However, the effect of VO on PersL remains still unclear enough to limit the development of PersL materials. In this study, the VO concentration of the Y2.978Ce0.018Yb0.004Al2Ga3O12 phosphor is accurately controlled by annealing in air and 10%H2/90%Ar atmospheres at various temperatures. The results show as the annealing temperature increases during the air annealing the VO concentration, the PersL durations, and the thermoluminescence (TL) intensity constantly decreases, and the three data coincide well with each other, indicating the PersL property of the Y2.978Ce0.018Yb0.004Al2Ga3O12 is successfully tuned. Besides, the trap structure of the Y2.978Ce0.018Yb0.004Al2Ga3O12 and the charge compensation effect of Yb ions on VO defects are also discussed. By deconvoluting the TL curves, the Yb trap with a depth of 0.58 eV has been distinctly separated from the VO traps with a quasi-continuous and broad distribution of depths ranging from 0.58 to 1.21 eV. Our work demonstrates a better understanding of the relationship between VO and PersL is of great significance to design a high-performance phosphor.