稀土离子(Eu3+,Tb3+,Ce3+)掺杂ZnAl2O4/SiO2微晶玻璃的制备与发光性能

采用凝胶法分别制备出4.5ZnO-5.5Al₂O₃-90SiO₂(ZAS)以及ZAS[DK]:RE³⁺ (RE=Eu,Tb,Ce) 透明微晶玻璃。利用X射线衍射仪(XRD)、透射电子显微镜(TEM)和荧光光谱仪(PL)等测试手段,研究了稀土离子掺杂浓度对ZAS微晶玻璃的结构和发光性能的影响。XRD结果表明,ZAS[DK]:RE³⁺ (RE=Eu,Tb,Ce)微晶玻璃包含ZnAl₂O₄晶相和SiO₂非晶相,ZnAl₂O₄平均晶粒尺寸约为30 nm,稀土离子的掺杂没有显著改变原来的ZnAl₂O₄晶体结构。TEM结果表明,900 ℃时ZnAl₂O₄从ZAS体系中析出。PL光谱显示,Eu³⁺ 存在 ⁵D₀→⁷F₂跃迁,ZAS[DK]:Eu³⁺在611 nm 处发出强烈的红色光;由于Tb³⁺ 的⁵D₄→⁷F₅ 跃迁,ZAS[DK]:Tb³⁺在541 nm 处发出明亮的绿色光;ZAS[DK]:Ce³⁺ 在381 nm处显示了蓝光发射,对应于Ce³⁺ 的5d→4f 轨道跃迁。ZAS[DK]:RE³⁺ (RE=Eu, Tb, Ce)的PL发射光谱存在着浓度猝灭现象,Eu³⁺、Tb³⁺ 和Ce³⁺的最佳单掺杂摩尔分数分别为20%、20%和3%。CIE色度图表明,ZAS[DK]: RE³⁺ (RE=Eu,Tb,Ce)的色坐标分别位于红光、绿光和蓝光区域。实验结果表明,ZAS:RE³⁺ (RE=Eu,Tb,Ce) 微晶玻璃是一种良好的可用于全色显示的白光LED材料。

Preparation and Luminescence Properties of ZnAl2O4/SiO2:RE3+ (RE=Eu,Tb, Ce) Glass Ceramics by Sol-gel Method

Transparent bulk glass ceramics of 4.5ZnO-5.5Al₂O₃-90SiO₂ (ZAS) and single doped ZAS:RE³⁺ (RE=Eu, Tb, Ce) were synthesized by sol-gel method. X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectra were employed to study the influence of doping rare-earth ions concentration on the structure and luminescence properties of ZAS glass-ceramics. XRD results show that ZAS:RE³⁺ (RE=Eu, Tb, Ce) glass ceramics heat-treated at 900 ℃ consist of ZnAl₂O₄ phase with average grain size of 30 nm and amorphous SiO₂. TEM results show that ZnAl₂O₄ were precipitated from ZAS system when heat-treated at 900 ℃, and doping ions have not changed the original structure. PL spectra indicate that ZAS:Eu³⁺ emits intense 611 nm red light originating from ⁵D₀→⁷F₂ transition of Eu³⁺ ions, ZAS:Tb³⁺ shows 541 nm green emission attributed to ⁵D₄→⁷F₅ transition of Tb³⁺ ions, and ZAS:Ce³⁺ gives 381 nm blue light corresponding to the 5d to 4f transition of Ce³⁺ ions. Furthermore, the concentration quenching phenomena are observed while the single doping mole fraction of Eu³⁺, Tb³⁺ and Ce³⁺ was 20%, 20% and 3%, respectively. The excellent Commission International de I'Eclairage (CIE) chromaticity coordinates of ZAS:RE³⁺ (RE=Eu, Tb, Ce) glass-ceramics indicate that they are good candidates for the application of white LEDs.