Near-infrared photo-stimulated red luminescence in Eu2+/Ln3+ (Ln = La-Lu):SrS persistent phosphors.

A series of Eu 2+ /Ln 3+ (Ln = La-Lu) co-doped SrS phosphors were successfully prepared by a conventional solid-state reaction. Both red persistent luminescence and near-infrared photo-stimulated red luminescence of Eu 2+ was observed in the Eu 2+ single-doped SrS sample benefited from the existence of intrinsic shallow and deep traps. Importantly, different to other Ln 3+ (Ln = La, Ce, Pr, Nd, Gd, Tb, Dy, Er, Ho, Tm, Yb, Lu) codopants, Sm 3+ ions were demonstrated to play an important role in increasing states/densities of deep traps, being beneficial to significantly enhance photo-stimulated red luminescence of Eu 2+ under the excitation of 808/980/1530 nm laser. Finally, persistent decay kinetics under the irradiation of periodically incident near-infrared laser were investigated to reveal the releasing process of electrons captured in the deep traps of Eu 2+ /Sm 3+ :SrS phosphor. [ABSTRACT FROM AUTHOR]