Tb^(3+)离子与SnO_2纳米晶体共掺杂SiO_2薄膜荧光增强

Enhanced Photoluminescence of Tb^(3+) Ions and SnO_2 Nanocrystals Codoped Silica Thin Films

为了提高Tb^(3+)离子在硅基薄膜中的吸收截面与光发射效率,本文通过在硅基薄膜中引入具有更大吸收截面的SnO_2纳米晶体,利用共振能量转移机制,大幅提高了Tb^(3+)离子的光发射效率。首先,利用限制性晶化原理,采用基于旋涂技术的溶胶凝胶法制备了Tb^(3+)离子与SnO_2纳米晶体共掺杂非晶SiO_2薄膜。然后,通过选择最佳掺杂浓度的SnO_2纳米晶体作为敏化剂,Tb^(3+)离子掺杂SiO_2薄膜在541 nm处的特征荧光发射强度增大了2个数量级。荧光激发谱与瞬态荧光寿命谱测试结果表明,Tb^(3+)离子与SnO_2纳米晶体之间存在着有效的非辐射复合能量传递过程,1 000℃高温退火后,部分Tb^(3+)离子进入纳米晶体内部,导致共振能量转移效率大幅提高。以上研究表明:SnO_2纳米晶体是一种潜在的Tb^(3+)离子敏化剂,可有效提高稀土Tb^(3+)离子掺杂SiO_2薄膜的光发射效率。

In order to improve the absorption cross section and increase the photoluminescence efficiency of Tb3＋ions doped silica thin film,SnO2 nanocrystals with larger absorption cross sections were introduced into the silica thin films,and the greatly enhanced photoluminescence intensity was obtained because of resonant energy transfer mechanism. Firstly,Tb3＋and SnO2 nanocrystals codoped silica thin films were fabricated by use of sol-gel and spin coating methods according to the restrictive crystallization principle. The characteristic photoluminescence emission intensity of Tb3＋ions at 541 nm was enhanced by two orders of magnitude for the film sensitized by SnO2 nanocrystals with the optimized Sn4 ＋concentration. The photoluminescence excitation spectra indicate the nonradiative energy transfer process that takes place between Tb3＋ions and surface of SnO2 nanocrystals. Meanwhile,the photoluminescence intensity decay curves suggest the partial incorporation of Tb3＋ions into the SnO2 sites,which explains the greatly improving energy transfer efficiency. Allthese results indicate that SnO2 nanocrystals could be benefit for enhanced photoluminescence of Tb3＋ions doped silica thin film as a potential sensitizer.