Effect of the doping of Al3+ ions on up-conversion luminescent performance of ZnGa2O4:Yb3+, Er3+ Phosphors

Al3+ doped ZnGa2O4:Yb3+, Er3+ powder phosphors with different Al3+ doping content were synthesized by solid-state method with subsequent thermal treatment at 1300 degrees C. The morphology, structural characterization and up-conversion luminescent properties of as-prepared samples were investigated by scanning electron microscope (SEM), x-ray diffraction (XRD) and LSP920 spectrofluorometer under the excitation of a 980 nm laser with different power density. In brief, all samples have good crystallinity and consist of long rods with width of 600-900 nm and length of 1-3 mu m. Under the 980 nm excitation, all phosphors can generate strong green emission at 524 nm, 549 nm (attributed to H-2(11/2) -> I-4(15/2) transition, S-4(3/2) -> I-4(15/2) transition of Er3+), red emission at 659 nm (corresponding to F-4(9/2) -> I-4(15/2) transition of Er3+) and slight blue emission at 410 nm (attributed to H-2(9/2) -> I-4(15/2) transition of Er3+). By contrast, the up-conversion efficiency and intensity raises with the doping of Al3+ ions. Accordingly, the doping of Al3+ ions has no effect on up-conversion emission peaks, but improve the up-conversion efficiency and intensity of phosphors.