Photoluminescence and afterglow behavior of orange-reddish Pr3+-activated Sr3Al2O6 phosphor

The orange-reddish Sr3Al2O6:Pr3+ samples were prepared using solid state reaction in air and the photoluminescence properties of the phosphors were investigated. The as-prepared phosphors were studied systematically by X-ray diffraction, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS), photoluminescence (PL) spectra, afterglow decay curves, thermoluminescence (TL) glow spectra, X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). The luminescence of Pr3+-activated Sr3Al2O6 exhibited a strong emission peak at 611 ​nm under 246 ​nm excitation arising from the intrinsic f-f transition of Pr3+ as an emitting centre. The ions of Pr3+ acted as not only the activators but also the providers of traps. The doping concentration of Pr3+ has a significant effect on the photoluminescence and long afterglow luminescence. The TL process and possible luminescence working mechanism of the Sr3Al2O6:Pr3+ were discussed in detail. The suitable and effective trap depths as well as the high concentration of defects for Sr3Al2O6 phosphors were obtained though the introduction of Pr3+ ions, greatly extending the lifespan of the electron-hole pair in the lattices for the improvement of the luminescent properties of Sr3Al2O6 long afterglow phosphors.