Luminescent and Long-Lasting Properties of Cd3Al2Ge3O12:Mn2+ Phosphor

Cd3Al2Ge3O12:Mn2+ afterglow phosphors were synthesized by the conventional solid-state reaction in this work, and the enhanced afterglow properties were observed with Zr4+ ions co-doping. The Cd3Al2Ge3O12:Mn2+, Zr4+ phosphors were characterized by using XRD, photoluminescence and thermoluminescence spectroscopy. The emission spectrum shows a broad emission band from 500 to 700 nm which is assigned to the T-4(1)((4)G)->(6)A(1)(S-6) transitions of Mn2+ ion. An energy transfer from the Cd3Al2Ge3O12 host to Mn2+ ions was observed. The center and the profile of the emission remain unchanged when co-doped with Zr4+ ions, but the introduction of Zr4+ ions improved the afterglow duration. Thermoluminescence spectra indicated that the introduction of Zr4+ into the host produces traps with suitable depth, resulting in the enhanced phosphorescence of Mn2+.