论文部分内容阅读
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。
Na3Gd1-xCexSi2O7 series phosphors were synthesized by high temperature solid-state reaction. The crystal structure of Na3GdSi2O7 was refined by Rietveld method using Na3LuSi2O7 structure model. The results show that the crystal structure of Na3GdSi2O7 is hexagonal and P63 / m, the lattice parameters a = b = 947.79 (1) pm and c = 1387.48 c / a = 1.4639. There are two Gd3 + (1) and Gd3 + (2) sites in Na3GdSi2O7 system. Gd3 + (1) ions are located in the Wyck.4f lattice, distorted octahedral structure. Gd3 + (2) ions are located in the Wyck.2a lattice, with a regular triangular prism configuration. The vacuum ultraviolet-UV-visible luminescence spectra of Na3Gd1-xCexSi2O7 phosphors were further investigated. The excitation band positions and energy levels of Ce3 + in the above two sites were discussed and identified. The emission spectrum curves are composed of two ~ 400 nm and ~ 508 nm broadband emission respectively. As the concentration of Ce3 + increases, the emission from short wavelength to 400 nm gradually increases.