Multi behaviors of Dy3+ for improving the luminescence properties of Pr3+-activated Sr3Al2O6 orange-reddish phosphors

Pr3+/Dy3+ co-doped Sr3Al2O6 phosphors were synthesized by a solid-state reaction. The powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and thermoluminescence (TL) were analyzed to investigate the luminescence and structure properties of the samples. The introduction of Dy3+ ions as multi behaviors significantly improve the luminescence properties of the phosphors. Dy3+ ions also behave as an emission center, showing the strong emission peaks at 617 nm and 645 nm, and work together with the activator of Pr3+ to responsible for the red color of the phosphors. The dopant of Dy3+ can significantly increase the trap concentrations with a suitable trap depth of 0.79 eV to extend the afterglow time of the materials. There exists some energy level overlaps among some excitation peaks of Dy3+ and some emission peaks of Pr3+, showing that Dy3+ ions still behave as sensitizers to improve the luminescence properties of the materials. Based on the energy band theory and defect theory, the luminescence mechanism of Pr3+/Dy3+ co-doped Sr3Al2O6 phosphors was proposed.