Persistent luminescence in BaGd2O4:Dy3+: from blue to infrared

This work reports a new persistent phosphor BaGd2O4:Dy3+. Its emission covers a broad spectral band from blue to infrared. The material was synthesized by coprecipitation method. The persistent phosphors were characterized by X-ray powder diffraction, photoluminescence, persistent luminescence and thermoluminescence spectra. After UV irradiation, BaGd2O4:Dy3+ phosphors show light yellow persistent luminescence (0.427, 0.418) at room temperature. Both of the photoluminescence and persistent luminescence is due to the F-6(9/2) -> H-6(J) transition of Dy3+. Energy transfer from Gd3+ to Dy3+ is observed. The deconvolution of the thermoluminescence curve reveals there are two kinds of traps responsible for the persistent luminescence. The depth of the dominating trap is 0.60 eV. Based on experimental results, an energy level scheme was proposed to explain the mechanisms of persistent luminescence as well as photoluminescence.