Synthesis And Luminescent Properties Of Ca₂Li₂BiV₃O₁₂:Eu³⁺ Phosphor

Rare earth vanadates are a kind of luminescent materials with advantages of lowsynthesis temperature, good chemical and thermostability which have expansiveutilization prospects. VO₄^3-shows high absorptions in near ultraviolet region andhigh-efficient sensitization to rare earth ions. In this study, a novel red phosphorCa₂Li₂BiV₃O₁₂:Eu³⁺with the potential application for solid state lighting wassynthesized by solid-state method. The phase composition, micromorphology andfluorescence spectra of samples were respectively characterized by X-ray diffraction（XRD）, scanning electron microscope （SEM） and fluorescencespectrophotometer（FL）. The influence of process parameters, including calcinationstemperature, holding time, and Eu³⁺ions concentration, on synthesized samples werestudied in detail. The potential luminescence mechanism was proposed, and theeffects of doping ions, including alkali metal ions, alkali-earth metal ions, and Y³⁺ions, on phase composition and fluorescence spectrum were also researched in thiswork.（1） The Ca₂Li₂BiV₃O₁₂:Eu³⁺samples can be obtained at600℃,650℃and700℃for3⁶h. XRD and SEM show that high purity and crystallinity ofCa₂Li₂BiV₃O₁₂:Eu³⁺can be obtained at650℃for4h.（2） In the fluorescence spectrum of Ca₂Li₂BiV₃O₁₂:Eu³⁺, the sample has abroad excitation band centered at²77nm,³23nm,³71nm and a number of sharpsmall peaks extending from385to480nm, corresponding to the f-f inner-shelltransitions of the Eu³⁺ions. The broad excitation band from200to385nm positionedat²77nm and³23nm is attributable to the allowed¹A₁â†'¹T₂and¹A₁â†'¹T₁transitions, respectively. And the broad excitation band positioned at³71nm is attributable to the¹S₀â†'³P₁transition of Bi³⁺ions. The emission spectra aredescribed by the well-known⁵D₀â†'⁷F_J（J=1,2,3,4） emission lines of the Eu³⁺ionswith the peak at612nm. And with the increasing of Eu³⁺ions, the luminous intensityof samples improve, The optimization condition is concentration of Eu³⁺ions14mol%.（3）10mol%Na+and K+ions （Na⁺or K⁺/Li⁺=1/9） can improve the luminousintensity of samples.（4） A small amounts of Mg²⁺, Sr²⁺and Ba²⁺ions can aslo improve the luminousintensity of samples with slight effect on phase composition. The optimizationconcentration of Mg²⁺, Sr²⁺and Ba²⁺ions is5mol%,10mol%and10mol%,respectively. And the main emission peak position shift from612nm to620nm as theSr²⁺and Ba²⁺ions doped.（5） The addition of Y³⁺ions has a slight effect on the phase composition butimproves the luminous intensity of samples perceptibly at the optimizationconcentration of20mol%. The color coordinates of samples are in a range of x=0.606⁰.639, and y=0.351⁰.371.