Luminescence properties of a Tb3+ activated long-afterglow phosphor

Luminescence properties of a new CaZnGe2O6:Tb3+ long-afterglow phosphor, including photoluminescence, excited-state decay curve, long-afterglow decay curve, and thermoluminescence curve, have been investigated in this paper. Photoluminescence spectra analysis shows that the Tb3+-doped CaZnGe2O6 phosphor emits intense green-lighting-emission from the 5D3,4 to 7FJ (J = 6, 5, 4, 3) transitions. Moreover, the Tb3+-related green-lighting-emission can last for more than 3 h after removal of the ultraviolet irradiation source. Both the excited-state decay curve and the long-afterglow decay curve of the Tb3+-doped CaZnGe2O6 phosphor contain a fast decay component and another slow decay one. Thermoluminescence curve indicates that the incorporation of Tb3+ ions into the CaZnGe2O6 host has produced suitable dense trapping centers with a thermoluminescence peak located at ca. 374 K, which is the origin of the long-afterglow phenomenon in this kind of material at room temperature. All the results indicate that the Tb3+-doped CaZnGe2O6 phosphor has promising potential of practical applications.