Color-tunable up-conversion luminescence of Zn(AlxGa1-x)2O4:Yb3+,Tm3+,Er3+ powders

Color-tunable up-conversion powder phosphors Zn(AlxGa1-x)2O4: Yb3+,Tm3+,Er3+ were synthesized via high temperature solid-state reaction. Also, the morphological and structural characterization, up-conversion luminescent properties were all investigated in this paper. In brief, under the excitation of a 980 nm laser, all powders have same emission peaks containing blue emission at 477 nm (attributed to 1G4→3H6 transition of Tm3+ ions), green emission at 526 nm and 549 nm (attributed to 2H11/2→ 4I15/2 and 4S3/2→4I15/2 transition of Er3+ ions respectively), red emission at about 659 nm and 694 nm (attributed to 4F9/2→4I15/2 transition of Er3+ ions and 3F3→3H6 transition of Tm3+ ions, respectively), which are not changed after the doping of Al3+ ions. However, the doping of Al3+ ions can enhance the up-conversion luminescent intensity and efficiency, while the emission color of as-prepared powder phosphors can be tunable by controlling the doping amount of Al3+ ions. Taking Zn(Al0.5Ga0.5)2O4:Yb,Tm,Er as the cut-off value, the emissions have clear blue-shift firstly and then show obvious red-shift with the increasing doping of Al3+ ions. Stated thus, pink emission in ZnAl2O4:Yb,Tm,Er, purplish pink emission in ZnGa2O4:Yb,Tm,Er and Zn(Al0.9Ga0.1)2O4:Yb,Tm,Er, purple emission in Zn(Al0.1Ga0.9)2O4:Yb,Tm,Er and Zn(Al0.3Ga0.7)2O4:Yb,Tm,Er, purplish blue emission in Zn(Al0.7Ga0.3)2O4:Yb,Tm,Er, blue emission in Zn(Al0.5Ga0.5)2O4:Yb,Tm,Er can be observed, which confirm the potential applications of as-prepared Zn(AlxGa1-x)2O4:Yb3+,Tm3+,Er3+ powder phosphors in luminous paint, infrared detection and so on.