Study On The Synthesis And Luminescent Properties Of (Y,La)VO₄: Eu～(3+)

The commercial red emitting phosphor (Y,Gd)BO₃:Eu³⁺ has high luminescent efficiency under UV and VUV excitation, but its color purity is not satisfied because of the inversion symmetry of Eu³⁺ sites. In this case, we choose a new luminescent material YVO₄:Eu³⁺ in which Eu³⁺ is located in non-inversion symmetry sites, this can remedy the drawback of poor color purity. In this paper, we synthesized YVO₄:Eu³⁺ by solid-state reaction and investigated the luminescent property by co-doping Bi³⁺, Sc³⁺; In the process of preparing YVO₄:Eu³⁺ by solid-state reaction, the color of samples is impurity for volatile V₂O₅, so we composite YVO₄:Eu³⁺ in low temperature and study the luminescence at different pH values and morphologies, heat treatment was performed on the sample with highest intensity. In the end, we investigated the luminescent property by doping La³⁺ in YVO₄:Eu³⁺ and prepared metastable phased LaVO₄:Eu³⁺, compared with with LaVO₄:Eu³⁺and YVO₄:Eu³⁺ which were prepared by solid state reaction.XRD patterns, TEM photographs, excitation spectra and emission spectra have been measured on the samples. The results indicated that: YVO₄:Eu³⁺ had good luminescence property and chromaticity, the excitated band of was broaden after doping Bi³⁺, but the relative intensity was decreased. After doping Sc³⁺, emission intensity was first increased, and then increased. Under 147 nm excitation, emission intensity of (Y,Bi,Sc)VO₄:Eu³⁺ was lower than YVO₄:Eu³⁺; YVO₄:Eu³⁺ which were synthesized via hydrothermal method were sphere-like and bar-like, respectively, the luminescence property was best when pH value was 7, and the best thermal treatment temperature was 800°C; Under UV and VUV excitation, the best doping concentration of La³⁺ was 0.025 for (Y,La)VO₄:Eu³⁺, and the best doping concentration of Eu³⁺ in tetragonal phased LaVO₄:Eu³⁺ was 0.05 and 0.10, respectively. Relative emission intensity of tetragonal phased LaVO₄:Eu³⁺ was far higher than monazite type bulk LaVO₄:Eu³⁺, was 70 % of bulk YVO₄:Eu³⁺, was 56% of commercial phosphor (Y,Gd)BO₃:Eu³⁺, respectively, also it has better chromaticity than(Y,Gd)BO₃:Eu³⁺.