用氯化钛合成二氧化钛：拉曼光谱和光致发光研究尺寸效应
Titanium dioxide synthesized using titanium chloride: Size effect study using Raman and Photoluminescence
摘要：
采用湿化学法制备了二氧化钛（TiO 2）纳米晶，并用X射线衍射（XRD）、透射电镜（TEM）、拉曼散射（RS）和光致发光（PL）等手段对其进行了表征。X射线衍射结果表明，两种样品均形成了平均粒径为7 nm和15 nm的纳米晶TiO 2。X射线衍射、透射电子显微镜（TEM）和拉曼散射（Raman）分析表明，两种样品的TiO 2纳米晶均为锐钛矿结构。小颗粒的PL强度较大，这是由于颗粒的缺陷和尺寸变化造成的。一个修正的声子约束模型，包括尺寸分布，一个新的约束函数的TiO 2纳米晶体和平均色散曲线的大部分色散声子分支（G-X方向）已被用来解释拉曼光谱的尺寸变化。得到的拉曼峰位移和半高宽与实验结果一致。我们的观察结果表明，声子限制效应是负责一个显着的移动和扩大的拉曼峰。
英文摘要：
Titanium dioxide (TiO2) nanocrystals were prepared by wet chemical method and characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Raman scattering (RS) and photoluminescence (PL). The X-ray diffraction shows the formation of nanocrytalline TiO2 of average sizes 7 nm and 15 nm for two samples. The x-ray diffraction, transmission electron microscopy (TEM) and Raman scattering shows that the TiO2 nanocrystals has anatase crystal structure for both samples. The PL intensity of the smaller particle is more, which has been attributed to defects and particle size variation. A modified phonon confinement model with the inclusion of size distribution, a new confinement function for TiO2 nanocrystals and averaged dispersion curves for most dispersion phonon branch (G-X direction) has been used to interpret the size variation of Raman spectra. The obtained Raman peak shift and FWHM agree will the experimental data. Our observations suggest that phonon confinement effects are responsible for a significant shift and broadening for the Raman peaks.
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