Luminescent properties of R+ doped Sr2MgSi2O7: Eu2+, Dy3+ (R+ = Li+, Ag+) phosphors

Long afterglow phosphor Sr2MgSi2O7: Eu2+, Dy3+ doped with R+ (R+ = Li+, Ag+, respectively) was synthesized by the high temperature solid-state reaction method. Crystal structure, morphological and luminescent properties were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence (PL), decay curves and thermoluminescence (TL) curves. The results indicate that the incorporation of these metal ions has no influence on the position of the emission peak which is determined by the 4f7→4f65d1 Eu2+ ions, but has influence on the intensity of the emission and the afterglow. The highest phosphorescent intensity was observed with 2.5 mol% of Li+, and 0.4 mol% of Ag+ doping in respectively. Compared with the undoped sample, the optimum incorporation of Li+ ions could induce a remarkable increase of phosphorescent intensity and the decay constant by about 1.5 times and 1.6 times, respectively. Doping Ag+ ions can also improve the luminescence properties, but the performance is not good as Li+ ions. The mechanism of Sr2MgSi2O7: Eu2+, Dy3+, R+ (R+ = Li+, Ag+, respectively) enhancement has been discussed.