溶胶-凝胶法制备TiO_(2):Yb,Er上转换纳米晶

TiO_(2):Yb,Er Upconversion Nanocrystals Prepared by the Sol-gel Method

通过溶胶-凝胶法制备了Yb^(3+)和Er^(3+)离子共掺的TiO_(2)纳米晶。通过X射线衍射、电镜扫描、荧光检测对制备的纳米晶微结构及形貌和发光性能进行表征。结果显示:纳米晶为纯锐钛矿相TiO_(2),形貌为类球形,平均粒径7-9nm,在980nm红外光激发下,其发射峰分别位于531nm、550nm、663nm处,发光强度随热处理(煅烧)温度升高及时间增加而增强,600℃4h为适宜的煅烧条件,样品的绿红发光强度比随激发光功率的增大而增大,显示出发光颜色的可调节性。依据发光强度与激发功率的关系,确定样品的发光为双光子过程,并分析了其上转换机制。

TiO_(2)Yb,Er nanocrystals were prepared by gel-gel method.The microstructure,morphology and luminescence properties of as-prepared nanocrystals were characterized by XRD,SEM and FA.The results showed that as-prepared nanocrystals possessed pure rutile phase microstructure,spherical-like and average size of about 7-9nm,the emission peaks located at 531nm,550nm,663nm respectively upon excitation with 980nm infrared laser,the emission intensity increases with the heat treatment(calcination)temperature and time,600℃4h was a suitable calcination condition,The green-red luminescence intensity ratio of as-prepared nanocrystals increases with the excitation light pump power,This phenomenon showed a modulation of the luminous color.According to the relationship between luminescence intensity and excitation power,the upconversion luminescence of as-prepared nanocrystals was come from two-photon energy transfer process,the upconversion mechanism was also analyzed.