Study On The Synthesis And Performance Of Rare Earth Phosphate And Vanadate Phosphors For White Light LEDs

Rare earth luminescent materials have a wide range of applications in the field of light-emitting luminescent materials such as energy-saving lighting,medical imaging,modern information technology and display detection.And fluorescent luminescent materials with high efficiency and stability and good luminescence properties are also of great significance in applications such as white LEDs.Phosphate is an excellent luminescent matrix material due to its good physicochemical stability.In this paper,in order to find a good performance of the red color phosphor for the three primary colors,on the one hand,an anion VO₄^3-is added to the yttrium phosphate matrix to realize the red color distribution.On the other hand,a good red phosphor was obtained by introducing cations?Li⁺,Na⁺and K⁺?as sensitizing ions and by heat treatment temperature regulation,and a series of Eu³⁺doped red phosphors were prepared by chemical coprecipitation.In the bisphosphonate matrix prepared by the high-temperature solid phase method,the color of the red light is adjusted by changing the ratio of the cations Ca²⁺and Sr²⁺,and the performance of the phosphor is further improved.In this paper,the transition of a matrix material from a monoclinic monazite structure to a tetragonal zircon structure is achieved by introducing vanadate in a phosphate matrix,completely converted to a tetragonal structure at a phosphorus to vanadium ratio of 1:1,and its red light emission center it also changes from ⁵D₀?⁷F₁ to⁵D₀?⁷F₂.The optimum calcination temperature of Gd(P_0.5V_0.5)O₄:Eu³⁺is 1200°C.In the effect of the concentration of the sample on the luminescence performance,the mechanism by which the luminescence is characterized by its performance is the charge transfer of the O^2-?Eu³⁺transition and the O^2-?V⁵⁺transfer to the Eu³⁺ion,which deviates from the inversion center to enhance the red emission strength.At the same time,there is also the transfer of energy between Gd³⁺?Eu³⁺.The introduction of vanadate not only enhances the red light emission intensity,but also enhances the absorption capacity of the material at 280?350 nm.The optimum doping concentration of Eu³⁺ions is 6at.%due to the critical value of the ions and the multipole interaction,its optimal color coordinate is?0.6234,0.337?,which can be used as a potential red phosphor luminescent material.The addition of alkali metal ions?Li⁺,Na⁺,and K⁺?to the matrix material promotes its red light emission intensity as an intermediate transfer body.The K(Sr_xCa_1-x)Gd?PO₄?₂ bisphosphate phosphors prepared by high temperature solid phase method,the increase of Sr²⁺ion realizes the transfer of Eu³⁺ion emission from orange red to red light emission.