摘要
高温固相法合成了Na3Gd1-xCexSi2O7系列荧光粉。利用Na3LuSi2O7结构模型,通过Rietveld方法精修了Na3GdSi2O7晶体结构,结果表明,Na3GdSi2O7属于六方晶系,P63/m点群,晶格参数a=b=947.79(1)pm,c=1387.48(3)pm,c/a=1.4639。Na3GdSi2O7体系中存在Gd3+(1)和Gd3+(2)两个格位。Gd3+(1)离子位于Wyck.4f格位,为扭曲八面体结构。Gd3+(2)离子位于Wyck.2a格位,具有正三棱柱构型。进一步考察了Na3Gd1-xCexSi2O7荧光粉的真空紫外-紫外-可见发光光谱,讨论并指认了Ce3+在上述两个格位中的激发带位置及能级重心。发射光谱曲线分别由两个~400 nm和~508 nm宽带发射构成,随着Ce3+浓度增加,短波~400 nm发射逐渐增强。
The Ce3+ doped sodium gadolinium pyrosilicates Na3Gd1-xCexSi2O7 phosphors were prepared through a high-temperature solid-state reaction technique.The crystal structure of Na3GdSi2O7 was refined by Rietveld method with Na3LuSi2O7 structure model.The results showed that the compound Na3GdSi2O7 crystallized in a hexagonal system(P63/m) with lattice parameters a=b=947.79(1) pm,c=1387.48(3) pm and c/a=1.4639.There were two Gd3+ lattice sites in Na3GdSi2O7,denoted Gd(1)3+ and Gd(2)3+.The Gd(1)3+ ions at Wyck.4f sites were with 6-fold distorted octahedron coordination(trigonal antiprism tap),and Gd(2)3+ ions at Wyck.2a sites were with 6-fold regular trigonal prism coordination(tp).The VUV-VIS luminescence properties of phosphors Na3Gd1-xCexSi2O7 were investigated,and the origin of these 4f-5d excitation bands and the 5d centroid of Ce3+ in two sites were assigned and discussed.The emission spectra of phosphors Na3Gd1-xCexSi2O7 were composed of broad band at ~400 and ~508 nm,respectively,and the relative intensity of Ce3+ emission at ~400 nm increased with the increasing of Ce3+ concentration.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2013年第1期38-43,共6页
Journal of the Chinese Society of Rare Earths
基金
广州市珠江科技新星(2011J2200034)
国家自然科学基金(20871121
10979027
21171176)资助