含水量对Tb:SiO_2光谱特性的影响  

Influence of the Amount of H_2O on the Emission Spectra of Tb Doped SiO_2 Xerogels

作　　者：潘静[1] 胡晓云[1] 刘国敬[1] 张德恺[1] 樊君[2] 

机构地区：[1]西北大学物理学系,陕西西安710069 [2]西北大学化工学院,陕西西安710069

出　　处：《光谱学与光谱分析》2010年第5期1179-1183,共5页Spectroscopy and Spectral Analysis

基　　金：西北大学研究生交叉学科项目(08YJC14);国家自然科学基金项目(20876125);陕西省教育厅科技计划项目(08JK451)资助

摘　　要：采用sol-gel法制备了稀土Tb3+掺杂的SiO2发光干凝胶,对样品微观结构和发光性能进行了表征,研究了含水量对样品荧光强弱,磷光特性,发光衰减等的影响。结果表明:当溶液中正硅酸乙酯、无水乙醇、蒸馏水配比为1∶4∶4时,650℃退火样品的发光最强,当配比为1∶4∶5时,750℃退火样品的发光最强,当配比为1∶4∶6时,850℃退火样品的发光最强。随着含水量的增加,经750℃退火处理的样品,发光强度先减弱后增强之后又减弱。可见,含水量和退火温度同时影响着Tb3+的发光,对发光强度的影响形成了一个竞争机制。通过测试磷光,初步得知基质中含有缺陷空位,含水量对磷光强度影响趋势与荧光的趋势一致。此外,含水量对发光衰减时间也有明显的影响。Tb-doped luminescent SiO2 xerogel was prepared by the sol-gel technique. FTIR was used to measure the microstructure of the luminescent materials. The luminescence properties were characterized by F-7000 UV-visible fluorescence spectrophotometer. The effects of the molar ratio of H2O on the fluorescence and phosphorescence intensity and phosphorescence lifetime of the sample were mainly investigated. The results showed that for the Tb^3＋ doped xerogels, the sample of 1∶4∶4 annealed at 650 ℃ reaches the maximum intensity, the sample of 1∶4∶5 annealed at 750 ℃ reaches the maximum, the sample of 1∶4∶6 annealed at 850 ℃ is the strongest. With increasing the amount of water, the luminous intensity of the samples annealed at 750 ℃ was first weakened, then enhanced and finally weakened. It was shown that the luminous intensity of samples is related to the molar ratio of aqueous solutions and annealing temperature, whose influence on the luminous intensity formed a competitive mechanism. Phosphorescence was observed at the same time, illustrating the existence of defects in the matrix space, and that the influence of water on the intensity is the same as that of fluorescence. In addition, with the increase in the molar ratio of aqueous solutions, the amount of defect gradually changed and resulted in a change in the luminescence decay time.

关 键 词：溶胶-凝胶法 二氧化硅干凝胶 稀土掺杂 发光特性 磷光寿命 

分 类 号：O482.3[理学—固体物理] O614.3[理学—物理]