Synthesis And Properties Of Gadolinium Phosphovanadate-based Single-phase White Phosphors For LEDs

White light emitting diodes（w LEDs）has been widely used in lighting and display.Commercially w LEDs are packaged with blue chips and YAG:Ce phosphors.Because people have diverse needs for lighting,it is of far-reaching significance to develop phosphors for w LED with high efficiency and stability that can be excited by ultraviolet.In this thesis,by introducing a certain amount of PO₄^3-into Gd VO₄ matrix,the luminescence intensity of VO₄^3-is tuned,by combining VO₄^3-blue emission with the characteristic emission of Bi³⁺,Sm³⁺and Dy³⁺,a series of color tuning was realized.Finally w LEDs were packaged with white light emitting phosphor and UV chip.It can be divided into the following aspects:In Gd（P_xV1-x）O₄:2 at.%Sm³⁺,the intensity of broad band emission from VO₄^3-can be regulated by changing the doping proportions of PO₄^3-/VO₄^3-,in consequence,the combination of VO₄^3-emission and characteristic Sm³⁺emission in different matrix of Gd（P_xV1-x）O₄ caused a series of color changing from orange-red to light-blue.On this basis,white light emitting phosphor Gd(P_0.6V_0.4)O₄:10 at.%Tb³⁺,0.5 at.%Sm³⁺with CCT=3997 K and Ra=84.8 was realized by adjusting concentration doping of Tb³⁺and Sm³⁺in Gd(P_0.6V_0.4)O₄:x at.%Tb³⁺,y at.%Sm³⁺.By changing the proportions of PO₄^3-/VO₄^3-in Gd(P_xV_1-x)O₄:1 at.%Sm³⁺,1 at.%Bi³⁺,the peak intensity and location of broad band emission from Bi³⁺,the characteristic emission peak intensity from Sm³⁺,as well as the energy transfer process among VO₄^3-,Sm³⁺,Bi³⁺can be effectively regulated.Finally,a w LED was packaged based on a 310 nm UV-chip and white light emitting phosphor Gd(P_0.7V_0.3)O₄:2 at.%Sm³⁺,1 at.%Bi³⁺.Electroluminescence（EL）spectrum was measured with corresponding CCT=3132 K and CRI=82.7.The combination of VO₄^3-emitting band and Dy³⁺characteristic emitting realized color tuning from yellow to white to cyan in Gd（P_xV1-x）O₄:1 at.%Dy³⁺.For single-phased white-light emitting Gd(P_0.3V_0.7)O₄:1at.%Dy³⁺phosphor,w LED was fabricated,J-O parameters and spectroscopic parameters were calculated in detail,quantum efficiency was also calculated to be 53.34%.The results mean single-phased Gd(P_0.3V_0.7)O₄:1at.%Dy³⁺can be a good candidate for UV-activated white-light emitting phosphor.