Li_2O-CaO-Gd_2O_3-SiO_2:Eu,Bi体系的结构和发光性能之间的关系

Relationship Between Luminescent Properties and Structures of Li_2O-CaO-Gd_2O_3-SiO_2 :Eu,Bi System

用X射线粉末衍射法研究了Li_2O-CaO-Gd_2O_3-SiO_2:Eu,Bi发光体系的物相组成随Gd_2O_3含量的变化,探讨了不同硅酸盐物种和结构对Eu^(3+)和Bi^(3+)发光特性的影响。结果表明,无Gd_2O_3组分时发光体是β-CaSiO_4多晶体,当Gd_2O_3/SiO_2比超过2.5％时,Ca_2Gd_8(SiO_4)_6O_2和LiGd_9(SiO_4)_6O_2物相逐渐增加,当其成为主要物相时,EU^(3+)发光呈数倍增强,这2种含钆物相的结构既利于EU^(3+)的红光发射又利于敏化剂向激活剂传输能量,所形成的固熔体是优良的发光基质材料。

The variations of phase components depending on the concentrations of Gd2O3 in the system of Li2O-CaO-Gd2O3-SiO2 : Eu,Bi were studied by powder X-ray diffraction. It was investigated that the structures and species of silicates affect the luminescent properties of Eu(Ⅱ) ion and Bi(Ⅲ) ion. If Gd concentration is small, the product is β-Ca2SiO4. The phases Ca2Gd8 (SiO4)6O2 and LiGd9(SiO4)6O2 appear and their contents increase with Gd2/O3 being 0. 25 when the ratio Gd2O3/SiO2 is more than 2. 5 wt% . The luminescence intensity of Eu3+ ion in the sample is five times that of Eu3+ ion in the sample with Gd2O3/SiO2 being 0. 2. The structures of the two phases containing Gd favor both red emission of Eu3+ ion and energy transfer from sensitizer to activator. The solid solution formed by the two compounds is a better host material than single LiGd9(SiO4)6O2 phase.