The long persistent luminescence properties of phosphors: Li2ZnGeO4 and Li2ZnGeO4:Mn2+

The blue emitting long persistent phosphor (LPP) Li2ZnGeO4 and green emitting LPP Li2ZnGeO4: Mn2+ were newly prepared by a high temperature solid-state reaction method. The blue and green afterglow with duration of 5 and 8 h were confirmed to originate from host emission and d-dtransitions of Mn2+ ions, respectively. The density of traps with suitable depth was significantly increased with the incorporation of Mn2+ ions. The energy transfer from host emission to Mn2+ ions was observed. The motion of charge carriers and a possible LAG mechanism based on a tentative model were illuminated and discussed in detail.