Evaluation of the role of oxygen vacancies in La3GaGe5O16:Tb3+ persistent phosphor

The persistent luminescence performance of a novel color-tunable Tb[Formula: see text]-doped La[Formula: see text]GaGe[Formula: see text]O[Formula: see text] phosphor has been modified by oxygen-deficiency control with an aim to explore the strategy to improve the persistent luminescence property. First-principles calculations were combined with thermoluminescence (TL) measurements to evaluate the role of oxygen vacancies in persistent luminescence of La[Formula: see text]GaGe[Formula: see text]O[Formula: see text]:Tb[Formula: see text] persistent phosphor. Our results show that the oxygen vacancies that act as an electron trap center have a limited contribution to the persistent luminescence. The formation of the ring structure of La[Formula: see text]GaGe[Formula: see text]O[Formula: see text] crystal and the resulting localized trap levels are very different from that of other outstanding persistent phosphors, like Sr[Formula: see text]MgSi[Formula: see text]O[Formula: see text], etc. Such differences are closely related to the inferior performance of La[Formula: see text]GaGe[Formula: see text]O[Formula: see text]:Tb[Formula: see text] persistent phosphor.