Deep-red photoluminescence and long persistent luminescence in double perovstkite-type La2MgGeO6:Mn4+

A novel non-rare-earth doped phosphor La2MgGeO6:Mn4+ (LMG:Mn4+) with near-infrared (NIR) long persistent luminescence (LPL) was successfully synthesized by solid-state reaction. The phosphors can be effectively excited using ultraviolet light, followed by a sharp deep-red emission peaking at 708nm, which is originated from E-2(g) -> (4)A(2g) transition of Mn4+ ions. The luminescent performance was analyzed by photoluminescence (PL) and photoluminescence excitation (PLE) spectra. The crystal field parameters were calculated to describe the environment of Mn4+ in LMG host. The LPL behaviors as well as the mechanisms were systematically discussed. This study suggests that the phosphors will broaden new horizons in designing and fabricating novel NIR long phosphorescent materials.