YTao4：Nb，Eu的发光性能研究

用高温固相反应法合成了铌酸根NbO^3-4和Eu^3 共掺杂的正钽酸盐化合物Y1－xEuxTa1-yNbyO4,研究该体系中紫外光和X射线激发下的发光性能，研究表明，在紫外光激发下，YTaO4:Nb,Eu是一种比较有效的红色发光材料，激发能可以通过NbO^3 4离子传递给Eu^3 ，随钽酸盐中NbO^3-4基团浓度的增中，化合物的结构从M'型YTaO4变成褐钇铌型YNbO4结构，它的发光性质也随之改变。

Luminescence Properties of YTaO4:Nb,Eu

A series of Y1-xEuxTa1-yNbyO4 (x=0－0.20,y=0－1.00) are synthesized by a modified solid state reaction method.When the concentration of NbO34- in yttrium tantalate is low,the structure of these systems is M′ type YTaO4.With increasing concentration of NbO34-,its structure completely changed from M′ type YTaO4 to fergusonite YNbO4.Under UV excitation,the emission spectra of YTaO4: Nb,Eu consist of two parts,the emission band between 300－450 nm is the charge transfer emission of NbO34-,and the sharp line emissions in the range of 500－720 nm originate from the transition of electrons in 4f shell of Eu3+.The main peak at 612.7 nm can be ascribed to the Eu3+5D0→7F2 transition and shows a strong red emission.Fixing the concentration of Nb5+ and Eu3+ separately,and changing the concentration of another ions,the luminescent properties of Y1-xEuxTa1-yNbyO4 will change rapidly.The difference of luminescence is originated from different structures.The excitation spectra of NbO34- emission (λ=400 nm) in YTa0.98Nb0.02O4 is a strong excitation band peak at 235 nm.In fact,the band is composed of charge transfer excitation of TaO34- and charge transfer excitation of NbO34-.The excitation spectra of Eu3+5D0→7F2 transition emission have two parts,the sharp lines between 300－600 nm and wide band between 200－300 nm.The sharp lines originate from Eu3+ f-f electron transitions,and the wide band includes both charge transfer excitation of TaO34- and NbO34-,and charge transfer excitation of Eu3+.The excitation spectra of NbO34- emission (λ=400 nm) in Y0.99 Eu0.01Ta0.98Nb0.02O4 is also a strong band,in which there also exists a charge transfer excitation of TaO34- and a charge transfer excitation of NbO34-.The strong evidence from excitation spectra,emission spectra of this system show that there is a energy transfer from host lattice to activator in the process of luminescence.