A novel rare-earth free red long-persistent phosphor: Mg2GeO4:Mn4+

Abstract Red-emitting long-persistent phosphor Mg 2 GeO 4 : Mn 4+ was prepared by a high-temperature solid-state reaction. The photoluminescence and afterglow properties of Mg 2 GeO 4 : xMn 4+ phosphors were studied systematically. Furthermore, to improve the afterglow performance, co-doped Re 3+ (Re = Pr, Er, Nd and Yb) ions into Mg 2 GeO 4 : 0.001Mn 4+ separately to adjust the trap depth or increase the trap density was performed. The duration of Mg 2 GeO 4 : 0.001Mn 4+ can be observed 30 min by naked eyes, and the initial brightness and afterglow duration are significantly improved after Re 3+ ions are doped respectively. Especially, the afterglow emission of Mg 2 GeO 4 : Mn 4+ , Yb 3+ can last for 2 h. This investigation shows up a rare Mn 4+ -doped long-afterglow phenomenon, and provides a new and efficient red afterglow material for potential application.