Wang Zhenling, Quan Zewei, Lin Jun
Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.
Inorg Chem. 2007 Jun 25;46(13):5237-42. doi: 10.1021/ic0701256. Epub 2007 May 23.
Highly uniform and well-dispersed CeO(2) and CeO(2):Eu(3+) (Sm(3+), Tb(3+)) nanocrystals were prepared by a nonhydrolytic solution route and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), UV/vis absorption, and photoluminescence (PL) spectra, respectively. The result of XRD indicates that the CeO(2) nanocrystals are well crystallized with a cubic structure. The TEM images illustrate that the average size of CeO(2) nanocrystals is about 3.5 nm in diameter. The absorption spectrum of CeO(2):Eu(3+) nanocrystals exhibits red-shifting with respect to that of the undoped CeO(2) nanocrystals. Under the excitation of 440 nm (or 426 nm) light, the colloidal solution of the undoped CeO(2) nanocrystals shows a very weak emission band with a maximum at 501 nm, which is remarkably enhanced by doping additional lanthanide ions (Eu(3+), Tb(3+), Sm(3+)) in the CeO(2) nanocrystals. The emission band is not due to the characteristic emission of the lanthanide ions but might arise from the oxygen vacancy which is introduced in the fluorite lattice of the CeO(2)nanocrystals to compensate the effective negative charge associated with the trivalent ions.
通过非水解溶液法制备了高度均匀且分散良好的CeO₂和CeO₂:Eu³⁺（Sm³⁺，Tb³⁺）纳米晶体，并分别通过X射线衍射（XRD）、透射电子显微镜（TEM）、X射线光电子能谱（XPS）、紫外/可见吸收光谱和光致发光（PL）光谱对其进行了表征。XRD结果表明CeO₂纳米晶体结晶良好，具有立方结构。TEM图像显示CeO₂纳米晶体的平均直径约为3.5 nm。CeO₂:Eu³⁺纳米晶体的吸收光谱相对于未掺杂的CeO₂纳米晶体呈现红移。在440 nm（或426 nm）光激发下，未掺杂的CeO₂纳米晶体的胶体溶液显示出一个非常弱的发射带，其最大值在501 nm处，通过在CeO₂纳米晶体中掺杂额外的镧系离子（Eu³⁺，Tb³⁺，Sm³⁺），该发射带显著增强。该发射带不是由于镧系离子的特征发射，而是可能源于在CeO₂纳米晶体的萤石晶格中引入的氧空位，以补偿与三价离子相关的有效负电荷。
