Thermally stable photoluminescence and long persistent luminescence of Ca3Ga4O9:Tb3+/Zn2+

A green long persistent luminescence (LPL) phosphor Ca3Ga4O9:Tb3+/Zn2+ was prepared. Ca3Ga4O9 matrix exhibits blue self-activated LPL due to the creation of intrinsic traps. When Tb3+ is doped, the photoluminescence (PL) and LPL colors change from blue to green with their intensities significantly enhanced. The doping of Zn2+ evidently improves the PL and LPL performances of the Ca3Ga4O9 matrix and Ca3Ga4O9:Tb3+. The thermoluminescence (TL) spectra show that a successive trap distribution is formed by multiple intrinsic traps with different depths in the Ca3Ga4O9 matrix, and the incorporation of Tb3+ and Zn2+ effectively increases the densities of these intrinsic traps. The existence of a successive trap distribution makes the Ca3Ga4O9:Tb3+/Zn2+ phosphor exhibit thermally stable PL and LPL. It is indicated that this phosphor shows great promise for the application such as high-temperature LPL phosphor. (C) 2018 Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.