受限条件下玻璃基质中LaF_3微晶生长机理的光谱学探究

Spectroscopic exploration of growth mechanism of LaF_3 nanocrystals embedded in glass ceramics under restricted conditions

利用高温熔融法制备了Eu3+掺杂的45SiO2-25Al2O3-18Na2O-9.5LaF3玻璃,并将基础玻璃在可控条件下进行晶化热处理后获得了性能良好的玻璃陶瓷.通过XRD,TEM和光谱学手段对玻璃陶瓷进行了表征,结果表明晶化热处理后,LaF3纳米晶体从原有单一的玻璃相中析出,晶粒大小约为25 nm.Eu3+掺杂玻璃陶瓷、纳米晶体和玻璃3种基质的光谱分析及XRD结果证明稀土离子进入到LaF3纳米晶体中并计算出在其中富集的比例.进一步利用源自于Eu3+离子的发射谱和激发谱研究了退火温度和前驱物中重金属离子对玻璃网络结构中LaF3纳米晶体生长影响的机理,为玻璃陶瓷的人工设计合成提供了理论支持.

Eu3＋ doped 45SiO2-25Al2O3-18Na2O-9.5LaF3-2.5EuF3 glass was successfully prepared via solid-state reaction, and the corresponding glass ceramics showing an excellent optical property was also synthesized by annealing the prepared glass at 700℃. The glass ceramics was characterized by XRD, TEM and spectroscopic routes. The results indicated that LaF3 nanocrystals with size about 25 nm were embedded uniformly into the annealed glass. The Eu3＋ ions in glass phase and crystal phase local environment are excited selectively using the spectroscopic strategy. The difference of emission spectra of Eu3＋ in the glass ceramics, nanocrystals and glass matrices was compared in detail. We made up the characteristic spectrum of Eu3＋ in glass ceramics using the spectra of Eu3＋ in nanocrystals and glass matrices and subsequently inferred the radio of rare-earth ions located in two kinds of local ambiences including glass phase and crystal phase ambience. The effects of annealing temperatures and heavy metallic ions in starting materials on the growth of LaF3 nanocrystals are explored as well.