Zhang Xiaoming, Quan Zewei, Yang Jun, Yang Piaoping, Lian Hongzhou, Lin Jun
State Key Laboratory of Application of Rare Earth Resources, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China. Graduate University of the Chinese Academy of Sciences, Beijing 100049, People's Republic of China.
Nanotechnology. 2008 Feb 20;19(7):075603. doi: 10.1088/0957-4484/19/7/075603. Epub 2008 Jan 29.
MF(2) (M = Ca,Sr,Ba) nanocrystals (NCs) were synthesized via a solvothermal process in the presence of oleic acid and characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectra, UV/vis absorption spectra, photoluminescence (PL) excitation and emission spectra, and lifetimes, respectively. In the synthetic process, oleic acid as a surfactant played a crucial role in confining the growth and solubility of the MF(2) NCs. The as-prepared CaF(2), SrF(2) and BaF(2) NCs present morphologies of truncated octahedron, cube and sheet in a narrow distribution, respectively. Possible growth mechanisms were proposed to explain these results. The as-prepared NCs are highly crystalline and can be well dispersed in cyclohexane to form stable and clear colloidal solutions, which demonstrate strong emission bands centred at 400 nm in photoluminescence (PL) spectra compared with the cyclohexane solvent. The PL properties of the colloidal solutions of the as-prepared NCs can be ascribed to the trap states of surface defects.
通过在油酸存在下的溶剂热法合成了MF₂（M = Ca、Sr、Ba）纳米晶体（NCs），并分别通过X射线衍射（XRD）、透射电子显微镜（TEM）、傅里叶变换红外（FT-IR）光谱、紫外/可见吸收光谱、光致发光（PL）激发和发射光谱以及寿命对其进行了表征。在合成过程中，油酸作为表面活性剂在限制MF₂ NCs的生长和溶解性方面起着关键作用。所制备的CaF₂、SrF₂和BaF₂ NCs分别呈现出截顶八面体、立方体和片状的形态，且分布较窄。提出了可能的生长机制来解释这些结果。所制备的NCs具有高度结晶性，并且可以很好地分散在环己烷中形成稳定且清澈的胶体溶液，与环己烷溶剂相比，这些胶体溶液在光致发光（PL）光谱中表现出以400 nm为中心的强发射带。所制备的NCs胶体溶液的PL特性可归因于表面缺陷的陷阱态。
