Enhanced Up-Conversion Emission in Al3+ Co-Doped ZnGa2O4:Yb3+,Tm3+ Powder Phosphors.

Yb3+-Tm3+ co-doped up-conversion powder phosphors using Zn(AlxGa1-x)2O4 (ZAGO) as the host materials were synthesized via solid-state reaction successfully. In addition, the morphology, structural characterization and up-conversion luminescent properties were all investigated by scanning electron microscope (SEM), x-ray diffraction (XRD) and fluorescence spectrophotometer (F-7000), respectively. Under the excitation of a 980 nm laser, all as-prepared powders can carry out blue emission at about 477 nm (corresponding to 1G4 → 3H6 transition of Tm3+ ions), and red emission at about 691 nm (attributed to 3F3 → 3H6 transition of Tm3+ ions). Also, the influence of doping Al3+ ions were investigated. In brief, the doping of Al3+ ions has no effect on the position of emission peak. Howbeit the up-conversion efficiency and intensity of ZAGO:Yb,Tm phosphors are stronger than ZGO:Yb,Tm and ZAO:Yb,Tm phosphors, while the crystallinity is the opposite. More particularly, all as-prepared powder phosphors emit strong luminescence, which is observable by the naked eye, demonstrating the potential applications in luminous paint, luminescent dye, etc.