Up-conversion luminescent materials of Y₂O₃:RE(RE=Er or Er/Yb) prepared by sol-gel combustion synthesis

Y₂O₃ powders doped with rare-earth ions were synthesized by sol-gel combustion synthesis. Effects of different calcinating temperatures, Er³⁺ doping concentration and Yb³⁺ doping concentration were investigated. It was shown that the single well crystallized Y₂O₃ powders could be obtained at 800°C; as the calcinating temperature increased, the crystallinity and upconversion luminescence intensity were higher; the particle size was uniform around 1 μm at 900°C; when Er³⁺ doping concentration was 1 mol%, the green upconversion luminescence intensity reached the maximum, but for red upconversion luminescence, when Er³⁺ doping concentration was 4 mol%, its luminescence intensity reached the maximum; as the ratio of Yb³⁺ to Er³⁺ was 4:1, the green emission intensity reached the maximum, while the red emission intensity was always increasing as Yb³⁺ doping concentration increased.