Phosphorescence performance of La_3GaGe_5O_16:Tb^3+ by enhancing the bridging oxygen vacancies

Abstract

La3GaGe5O16:Tb3+ phosphors deliver a long color-tuning persistent luminescence arising from the defect related emission and the 4f - 4f transitions of Tb3+. The persistent luminescence color was tuned by changing the doping Tb3+ concentration. The effect of the different atmospheres on the persistent luminescence of Tb3+-doped La3GaGe5O16 was investigated. Furthermore, we modified the composition around Tb3+ by adjusting the Ge/O content and improved the performance of persistent luminescence of the La3GaGe5O16:Tb3+. The samples synthesized in the poor-oxygen atmosphere most likely exhibited more exceptional persistent phosphorescence by enhancing the oxygen vacancies. To gain insight into the trapping and releasing processes involved in the persistent luminescence, we conducted a series of TL measurements by combining with the first-principles theory calculation. In addition, more investigations were carried out to unravel the nature of traps and also to verify the rationality of the material design.