Enhanced afterglow behavior of a new Eu2+: Sr2Al2SiO7 green phosphor co-doped with different cations Nd3+, Dy3+, Ho3+, Tm3+ and Yb3+

Eu2+ and Ln3+ (Ln3+ = Nd3+, Dy3+, Ho3+, Tm3+, Yb3+) co-doped Sr2Al2SiO7 green-phosphors were synthesized via high temperature solid state method. The XRD analysis proved that the obtained phosphors are all pure-phased. To investigate the luminescent properties, the analysis of fluorescence, afterglow luminescence, photo-stimulated luminescence and diffuse reflection spectrum were conducted. It is evident that the central positions of excitation and emission spectra remained unchanged. However, the intensity and decay time of the afterglow and photo-stimulated luminescence of Eu2+ were tunable through doping with various Ln3+ ions. Among them, Eu2+ and Tm3+ co-doped Sr2Al2SiO7 exhibits excellent photo-stimulated luminescence properties. Moreover, the results from thermoluminescence (TL) measurements suggest that the introduction of Tm3+ doping induces deeper traps. Additionally, afterglow decay and TL curves were assessed, highlighting the exceptional phosphorescent properties exhibited by the present phosphors.