CaF_2微晶玻璃的一步法制备及Eu~(3+)离子探针特性

以组成为n(SiO_2)∶n(Al2O3)∶n(CaO)∶n(CaF_2)∶n(NaF)∶n(B_2O_3)=40∶20∶10∶10∶15∶5的微晶发光玻璃为基质,采用一步析晶法制备了CaF_2析晶相.利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、X射线能量散射谱仪(EDS)和荧光分光光度计等对样品结构、组成及光谱性能进行分析,探讨了Eu3+掺杂浓度和析晶温度对微晶玻璃发光性能的影响.实验结果表明,在850℃下处理可获得分布均匀、粒径尺寸为200 nm的CaF_2析晶相,微晶玻璃的发光强度是基质玻璃的1.7倍.微晶玻璃的发射光谱在590,614,652和700 nm出现发射峰,分别对应Eu3+的5D0-7FJ(J=1,2,3,4)跃迁.通过对5D0-7F1和5D0-7F2跃迁强度的分析以及Judd-Ofelt理论参数Ω2值的计算可知Eu3+周围晶体场在析晶前后对称性发生变化.机理分析表明,析晶处理后Eu3+从高声子能量的Si-O环境进入低声子能量的Ca-F环境中,说明Eu3+可作为荧光探针研究微晶玻璃晶体结构的变化.

Preparation of Glass Ceramics Containing CaF2 by One-step Method and Analysis of the Fluorescent Probe of Eu3+Ion

Transparent glass-ceramics with composition n(SiO2):n(Al2O3):n(CaO):n(CaF2):n(NaF):n( B2 O3 )=40:20:10:10:15:5 were fabricated via traditional melting technique with one-step method. X-ray diffraction( XRD) results of as-prepared glass-ceramics confirmed the existence of CaF2 phase. Scanning electron microscopy( SEM) observation showed that the CaF2 crystalline phase had a size of 200 nm and dis-persed in the amorphous phase. The fluorescence intensity of glass ceramics was 1. 7 times that of the glass. The emission spectrum showed several luminescence peaks at 590 nm( 5 D0→7 F1 ) , 614 nm( 5 D0→7 F2 ) , 652 nm ( 5 D0→7 F3 ) and 700 nm( 5 D0→7 F4 ) , which are attributed to the Eu3+ion transition. The intensity ratio of 5 D0-7 F2 transition to the 5 D0-7 F1 transition and Ω2 of Judd-Ofelt parameters were used to measure the rare earth ion site symmetry. The data revealed that Eu3+ions are embedded into Ca-F environment from Si-O envi-ronment during the crystallization process. Therefore Eu3+can be applied to investigate the microstructures of glass-ceramic crystal as a fluorescence probe.