Li6(La2Ca)Nb2O12基质中掺杂Dy3+离子的发光性质研究

采用高温固相法制备了Li₆(La₂Ca)Nb₂O₁₂:Dy³⁺荧光粉样品,通过X射线衍射分析了样品的晶体结构,并利用光谱技术研究了样品的光致荧光光谱.光谱分析结果表明,Li₆(La₂Ca)Nb₂O₁₂:Dy³⁺的激发光谱由两部分组成:一是位于200～290 nm的一个宽带,峰值位于269 nm,属于Nb—O、Dy—O的电荷迁移带的叠加; 二是位于310～500 nm之间的系列尖锐的吸收峰,这些激发峰属于Dy³⁺的f →f跃迁.样品可被近紫外或蓝光LED有效激发.在269 nm激发下,样品在580 nm处有很强的黄光发射,色坐标为(0.470 3,0.492 7).随着Dy³⁺掺杂浓度的增加,样品的发光强度增强,当Dy³⁺浓度为10 mol%时出现浓度猝灭.

Luminescence properties of Dy~(3+) ion doped Li_6(La_2Ca)Nb_2O_(12) phosphor

A novel phosphor Li₆(La₂Ca)Nb₂O₁₂:Dy³⁺ was successfully prepared by high temperature solid phase method. The XRD patterns and photoluminescence spectra of the samples were studied by X-ray diffractometer and fluorescence spectrophotometer. Spectral analysis results show that the excitation spectrum of Li₆(La₂Ca)Nb₂O₁₂:Dy³⁺ exhibits two parts: one is a broad absorbtion band at 200-290 nm centered at 269 nm, which is assigned the charge transfer band(CTB)of Nb—O and Dy—O; the second is a series of sharp absorption peaks between 310 nm and 500 nm. These excitation peaks belong to the f →f transition of Dy³⁺ ion, which could be excited with the nUV or blue LEDs. Under the excitation of 269 nm, the color coordinates of the emission spectrum are(0.470 3,0.492 7), which is located in the yellow region at 580 nm. The luminescence intensities of the samples increased with the increase of content of Dy³⁺ till x=10 mol%. When the concentration of Dy³⁺ is over 10 mol%, the luminescence intensities decreased due to the concentration quenching mechanism.