A new long-lasting phosphor Zr4+ and Eu3+ co-doped SrMg2(PO4)2

Zr4+- and Eu3+-codoped SrMg2(PO4)2 phosphors were prepared by conventional solid-state reaction. Under the excitation of ultraviolet light, the emission spectra of Sr0.95Eu0.05Mg2−2xZr2xP2O8 (x = 0.0005–0.07) are composed of a broad emission band peaking at 500 nm from Zr4+-emission and the characteristic emission lines from the 5D0 → 7FJ (J = 0, 1, 2, 3 and 4) transitions of Eu3+ ions. These phosphors show the long-lasting phosphorescence. The emission color varies from red to white with increasing Zr4+-content. The white-light emission is realized in single-phase phosphor of Sr0.95Eu0.05Mg2−2xZr2xP2O8 (x = 0.07) by combining the Zr4+- and Eu3+-emission. The duration of the persistent luminescence of Sr0.95Eu0.05Mg2−2xZr2xP2O8 (x = 0.07) reaches nearly 1.5 h. The time at which the long-lasting phosphorescence intensity is 50% of its original value (T0.5) is 410 s. The afterglow decay curves and the thermoluminescence spectra were measured to discuss this long-lasting phosphorescence phenomenon. The co-doped Zr4+ ions act as both the luminescence centers and trap-creating ions.