摘要
研究α-NaYF4∶Yb,Er上转换纳米粒子的W/O微乳液溶剂热制备,并用正硅酸乙酯为SiO2前驱体对NaYF4∶Yb,Er上转换纳米粒子进行SiO2包覆,分析SiO2包覆对Er3+发光增强作用来自于两方面。包覆弥补上转换纳米粒子表面的发光粹灭中心,提高上转换发光强度。同时由于Si—O—Si的对称振动能量1 106 cm-1与4F7/2能级到2H11/2能级弛豫能量1 177cm-1相当,(CH2)n的红外振动模能量为743 cm-1与2H11/2能级到4S3/2弛豫能量780 cm-1相当,4F7/2能级到4F9/2弛豫能量为5 023 cm-1,4I11/2能级到4I13/2弛豫能量接近4 500 cm-1,与Si—O—Si的对称伸缩振动能量1 106 cm-1不匹配,所以SiO2包覆能有效的增加表面发光中心2H11/2,4S3/2能级布居数,而使得产生红光发射的能级4F9/2能级布居数不变。
The cubic NaYF4 ：Yb,Er nanoparticles coated with silica were synthesized and characterized. The upconversion luminescence spectra of Er^3＋ doped cubic sodium yittrium fluoride nanoparticles and particles coated with silica were analysed. The results demonstrate that silica coat can increase surface luminescence center by decreasing surface lattice defects efficiently. Besides, Si--O--Si vibration energy 1 106 cm^-1 is fit to realaxation process from ^4F3/2 to ^2H11/2 and from ^2H11/2 ^4S3/2 . However, it can＇t enhance ^4F9/2 reservior at cross relaxation process from ^4F7/2 to ^4F9/2 （5 025 cm^-1 ） and from ^4I11/2 to ^4I13/2 （4 500 cm^-1）. So silica coats increase ^2H11/2, ^4S3/2 reservior at surface luminescence centers and do not change ^4F9/2 reserviors of all.
出处
《兵器材料科学与工程》
CAS
CSCD
2009年第3期52-55,共4页
Ordnance Material Science and Engineering
