中国物理B ›› 2012, Vol. 21 ›› Issue (7): 73201-073201.doi: 10.1088/1674-1056/21/7/073201
• ATOMIC AND MOLECULAR PHYSICS • 上一篇 下一篇
何恩节, 刘宁, 章毛连, 秦炎福, 官邦贵, 李勇, 郭明磊
He En-Jie(何恩节) Liu Ning(刘宁)†, Zhang Mao-Lian(章毛连), Qin Yan-Fu(秦炎福), Guan Bang-Gui(官邦贵), Li Yong(李勇), and Guo Ming-Lei(郭明磊)
摘要: By employing a certain proportion of hydrogen peroxide, ammonia, ammonium fluoride and ethylene diamine tetraacetic acid (EDTA) as precipitator, well-crystallized LaOF:Eu3+ and LaOF:Yb3+, Er3+ nanocrystals are synthesized with chemical co-precipitation method. The structural properties of these samples are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR) spectra. The results show that all the samples have an average size below 70 nm and decreases gradually with the increase of the EDTA content, and a certain number of EDTA molecules are coupled with doped ions on the surfaces of nanocrystals. Most of the doped ions are proved to be enriched on the surfaces of nanocrystals and surrounded by the high energy vibration groups and bonds in EDTA molecules. The observed differences in upconversion emission spectrum among the different LaOF:Yb3+, Er3+ nanocrystals are explained by the different two-photon upconversion mechanisms. Especially, in the LaOF:Yb3+, Er3+ nanocrystals with EDTA, the two-photon processes that contain several special cross relaxation processes are introduced to analyse the corresponding upconversion mechanisms.
中图分类号: (Visible and ultraviolet spectra)