Effect Of Non-rare Earth Metal Ions Doping On The Properties Of CaGd₂（WO₄）₄:Re³⁺ Powder Phosphor

Tungstate phosphors is a potential application material for WLED because of its unique crystal structure,excellent optical properties,stable physical and chemical properties,non-toxic,easy to prepare and low preparation cost.How to improve the luminous properties of tungstate-based phosphors has become the focus of the current research.This paper mainly studies the effect of non-rare earth metal ions on the photoluminescence properties of tungstate phosphors.In this paper,CaGd₂（WO₄）₄:RE³⁺phosphors were successfully prepared by simple hydrothermal synthesis,and the photoluminescence properties of CaGd₂（WO₄）₄:RE³⁺phosphors were improved by doping metal ions Mⁿ⁺(Na⁺,K⁺,Mg²⁺,Al³⁺).The phase and crystal structure were analyzed by X-ray diffraction,and the luminescence intensity,quantum efficiency and fluorescence lifetime were analyzed by fluorescence spectrometer.The effect of non-rare earth metal ions doping on the photoluminescence properties of tungstate phosphors was studied.The main research contents and conclusions are as follows:（1）Different concentrations of metal ion Mⁿ⁺(Na⁺,K⁺,Mg²⁺,Al³⁺)doped CaGd_1.3（WO₄）₄:0.7RE³⁺:Mⁿ⁺phosphors were prepared by hydrothermal synthesis.The crystal structure of each sample did not change and belonged to monoclinic scheelite structure,but the intensity of the diffraction peak was different.Among them,the intensity of the diffraction peak of the sample was improved to a certain extent by doping Na⁺,K⁺and Mg²⁺,while the intensity of the diffraction peak was greatly reduced by doping Al³⁺.（2）The luminous intensity of Mⁿ⁺(Na⁺,K⁺,Mg²⁺,Al³⁺)doped CaGd_1.3（WO₄）₄:0.7Eu³⁺:Mⁿ⁺phosphors has been changed.When the doping amount of Na⁺is 0.03,the emission intensity of the sample reaches the maximum,which is 308%higher than that of undoped;when the amount of K⁺doping is 0.03,the emission intensity of the sample increases 186%;when the doping amount of Mg²⁺is 0.03,the emission intensity of the sample increases 57%,while the luminous intensity of the phosphor doped with Al³⁺decreases obviously.（3）The quantum efficiency of metal ion Mⁿ⁺(Na⁺,K⁺,Mg²⁺,Al³⁺)doped CaGd_1.3（WO₄）₄:0.7Eu³⁺:Mⁿ⁺phosphor is as follows.Compared with the undoped CaGd_1.3（WO₄）₄:0.7Eu³⁺phosphor when the Na⁺doping amount is 0.03,the quantum efficiency increases 135%,when the K⁺doping content is 0.03,the quantum efficiency increases 84%,and when the Mg²⁺doping amount is 0.03,the quantum efficiency increases 44%.However,the quantum efficiency of the samples decreased with the addition of Al³⁺.Na⁺,K⁺and Mg²⁺doping can increase the probability of radiative transition and increase the fluorescence lifetime of the sample,while Al³⁺doping reduces the radiative transition,thus shortening the fluorescence lifetime of the sample.（4）The luminous intensity of CaGd_1.3（WO₄）₄:0.7Tb³⁺:Mⁿ⁺phosphors doped with Mⁿ⁺(Na⁺,K⁺,Mg²⁺,Al³⁺)has been changed.When the doping amount of Na⁺is 0.05,the emission intensity of the sample reaches the maximum,which is 46%higher than that of undoped;when the amount of K⁺doping is 0.03,the emission intensity of the sample increases by 80%;when the doping amount of Mg²⁺is 0.05,the emission intensity of the sample increases by 65%,while the luminous intensity of the phosphor doped with Al³⁺decreases obviously.（5）The quantum efficiency of Mⁿ⁺(Na⁺,K⁺,Mg²⁺,Al³⁺)doped CaGd_1.3（WO₄）₄:0.7Tb³⁺:Mⁿ⁺phosphor is as follows.Compared with the undoped CaGd_1.3（WO₄）₄:0.7Tb³⁺phosphor,when the Na⁺doping content is 0.05 the quantum efficiency increases 74%,when the K⁺doping content is 0.03,the quantum efficiency increases 120%,and when the Mg²⁺doping amount is 0.05,the quantum efficiency increases 102%.However,the quantum efficiency of the samples decreased with the addition of Al³⁺.Na⁺,K⁺and Mg²⁺doping can increase the probability of radiative transition and increase the fluorescence lifetime of the sample,while Al³⁺doping reduces the radiative transition,thus shortening the fluorescence lifetime of the sample.In summary,the tungstate phosphors prepared by hydrothermal method have good crystallization properties,and proper metal ion doping can greatly improve the photoluminescence properties of tungstate.