Study On Luminescent Properties And Modification Of Gd₂O₃:Eu³⁺ Phosphors

Rare earth doped oxide phosphors are widely used in many fields, such as field display, cathode ray tube, plasma display, white light emitting diodes, tri-color energy-saving lamps, molecular probe and so on, due to their long serving longevity,high color rendering, high thermal stability and environment amity. In order to study the effect of non-rare-earth metal ions on the luminescence properties of rare earth oxide phosphors, Gd2O3:Eu3+phosphors with different concentration ratio of Gd3+to Eu3+ were prepared by hydrothermal method in this dissertation. The optimum doping concentration was achieved after relative examinations. On the basis, the non rare earth ions Li+,K+,Mg2+ co-doped Gd2O3:Eu3+ phosphors were synthesized by the same method. The effect of co-doped ions on the structural, morphological, and luminescent properties were studied by means of X-ray diffraction（XRD）, scanning electron microscope（SEM）, and PL spectra.Major results as followed:（1） When the molar ratio of Gd³⁺:Eu³⁺ is 20:1, the luminescent intensity reaches highest. After doping Li+, Mg2+, K+ and Al3+, the spectra became stronger with the increase of doping concentration. When the molar ratio of Gd³⁺:Eu³⁺:Li+ is 20:1:0.5,the molar ratio of Gd³⁺:Eu³⁺:Mg2+, Gd³⁺:Eu³⁺:K+ and Gd³⁺:Eu³⁺:Al3+ is 20:1:1, the luminescent intensity reaches maximum, which is 2.3 times, 1.9 times, 1.7 times and1.6 times of un-doping ones respectively. Correspondingly, the quantum efficient increase 15 %,9 %,6 %,4 %, and the fluorescence decay time is 0.16 ms,0.11 ms,0.03 ms,0.07 ms shorter than un-doping ones. The results show that there is a phenomenon of concentration quenching when non-rare-earth metal ions are doped,which have a certain effect on the luminescent properties.（2） There is a close relation among crystallization morphology, the luminous intensity, quantum efficiency and the fluorescence decay time. Better crystallization,more uniform morphologies, similar length and width will increase luminous intensity, improve quantum efficiency and reduce fluorescence decay time.In summary, rare earth oxide phosphors of hydrothermal synthesis has goodcrystallization, moderate doped concentration can optimize the luminescent properties, so as to achieve the purpose of cutting the costs and reducing environmental pollution.