Commendable Pr3+-activated Ba2Ga2GeO7 phosphor with high-brightness white long-persistent luminescence

Abstract

Long-persistent phosphors can be used in diverse fields, such as emergency instruction, information storage and in vivo bioimaging. Currently, progress in research and development of white long-persistent phosphors is slow, although there is growing demand for applications in certain conditions. In this work, a novel white long-persistent phosphor Ba₂Ga₂GeO₇:Pr³⁺ was synthesized and systematically investigated through its structural information, photoluminescence and phosphorescence properties. Under ultraviolet light excitation, this phosphor gives white emission containing greenish-blue and red components stemming from ³P₀ and ¹D₂ multiplet electron transitions in the 4f level of Pr³⁺. The luminescent color of the phosphors is relatively stable at different temperatures and Pr³⁺ concentrations. Bright white afterglow can be observed by the naked eye in the dark for 3 hours after removal of the excitation source. Finally, a feasible afterglow mechanism of Ba₂Ga₂GeO₇:Pr³⁺ with a trap–detrap scenario was proposed to clarify the generation of the white afterglow.