Long persistent and photostimulated luminescence properties of Sr2Al2SiO7:Eu2+/Tm3+ phosphors

A series of Sr2Al2SiO7 phosphors with fixed Eu2+ concentration and various Tm3+ concentrations were synthesized via a high temperature solid state reaction. The structure and luminescence properties of the samples were characterized by X-ray powder diffraction (XRD), photoluminescence (PL) spectra, decay curves, thermoluminescence (TL) glow curves as well as the photostimulated luminescence (PSL) spectra. Sr2Al2SiO7:Eu2+, Tm3+ phosphors exhibited strong green phosphorescence and photostimulated luminescence originating from 4f65d1–4f7 transition of Eu2+ after ultraviolet light stimulation. Deep traps were found by analyses on the phosphorescence decays and thermoluminescence spectra. It was also found that with increasing the time interval between UV excitation turn-off and stimulation turn-on, the photostimulated luminescence became stronger. This phenomenon resulted from the fact that the captured electron was retrapped by the deep traps. Compared with the Tm3+-free sample, it was found that the PSL intensity was strongly enhanced in Tm3+ codoping samples.

Graphical AbstractPSL and TL (at 490 K) intensities of Sr1.98–xAl2SiO7: 0.02Eu2+/xTm3+ (x=0, 0.001, 0.005, 0.01, 0.02, 0.04) labeled from sample 1 to 6Figure optionsDownload as PowerPoint slide