Eu^(2+)和Dy^(3+)掺杂浓度对Sr_2MgSi_2O_7材料的荧光和长余辉性能的影响  

Influence of Eu^(2+) and Dy^(3+) Concentrations on Fluorescence and Phosphorescence of Sr_2MgSi_2O_7 Phosphors

作　　者：毛启楠[1] 李鹤[1] 季振国[1] 席俊华[1] 张峻[1] 孔哲[1] 

机构地区：[1]杭州电子科技大学材料与环境工程学院,杭州310018

出　　处：《无机材料学报》2016年第8期819-826,共8页Journal of Inorganic Materials

基　　金：国家自然科学基金(61372025);浙江省自然科学基金(LY15E030009);浙江省科技计划项目(2014C33220;2015C37037)~~

摘　　要：采用高温固相法制备得到Sr_2Mg Si_2O_7:Eu^(2+)和Sr_2Mg Si_2O_7:Eu^(2+),Dy^(3+)发光粉,并详细研究了Eu^(2+)和Dy^(3+)的掺杂浓度对Sr_2Mg Si_2O_7材料的荧光和长余辉性能的影响。所有样品都在470 nm附近呈现较宽的发光峰,这可归因于Eu^(2+)离子的4f^65d→4f^7电子能级跃迁。当Eu^(2+)掺杂浓度超过淬灭浓度,其浓度淬灭效应导致发光粉的荧光强度下降和余辉时间减短。同时,发射峰的峰位随Eu^(2+)浓度的增加而发生红移,这主要由于晶体场分裂能和斯托克斯位移变化造成的,而电子云扩大效应变化所产生的影响相对较弱。Dy^(3+)离子会抑制荧光,但有助于延长余辉时间。当其掺杂浓度超过10mol%时,Eu^(2+)\Dy^(3+)离子通过隧道复合机制发生浓度淬灭,从而使材料的长余辉寿命减少。Eu^（2＋）-doped Sr_2 Mg Si_2O_7 and Eu^（2＋） and Dy^（3＋） codoped Sr_2 Mg Si_2O_7 phosphors were synthesized by conventional solid-state reaction. Eu^（2＋） and Dy^（3＋） concentration effects on the fluorescence and phosphorescence of Sr_2 Mg Si_2O_7phosphors were studied. All the samples show a broad emission band centered at about 470 nm, which are ascribed to 4f^65d→4f^7 transition of Eu^（2＋） ions. Concentration quenching is found to be the dominant factor decreasing emission intensity and afterglow duration time when Eu^（2＋） doping level exceeds the critical concentration. Redshift of the emission bands is also observed as the Eu^（2＋） concentration increasing. In order to explain the redshift of the emission bands, the centroid position of 5d level of Eu^（2＋）, crystal-field splitting energy and Stokes shift are estimated from excitation and emission spectra. Based on the calculation, the redshift of the emission bands mainly results from the variations of crystal-field splitting energy and Stokes shift, but is less influenced by the nephelauxetic effect. The Dy^（3＋） ions suppress the fluorescence but enhance the phosphorescence lifetime. When the Dy^（3＋） concentration is over 10mol%, the phosphorescence lifetime is shortened, because of concentration quenching of the Eu^（2＋）／Dy^（3＋） ions by the mechanism of tunneling recombination.

关 键 词：硅酸镁锶 发光性能 掺杂 浓度淬灭 

分 类 号：TB34[一般工业技术—材料科学与工程]