纳米锐钛矿的拉曼光谱特征

Study on Raman Spectrum of Nanophase Anatase

本文是采用化学沉淀法合成出 2～ 40nm的纳米锐钛矿 ,测定并研究了不同粒径的纳米锐钛矿样品及 μm级和天然锐钛矿的拉曼光谱 ,结果表明 :随着晶粒尺寸的减小 ,谱带强度大幅度降低 ,谱带蓝移。其中 ,143cm-1处谱带蓝移程度最大 ,达到 10cm-1(2nm锐钛矿和天然锐钛矿比较 ) ;随着晶粒尺寸的减小 ,5 15和 6 37cm-1处谱带蓝移达到一个最大值后 ,当粒度继续减小时 ,却产生红移 ;396cm-1谱带随着粒度的减小 ,谱带没有明显位移。这些现象反映了纳米材料结构的复杂性。我们把这种现象主要归于晶粒内部发生了弹性畸变 ,使振动能级发生了改变。

The nanophase anatase of different sizes (2—4 0 nm) were synthesized with chemical precipitation method.Nanophase anatase (2—40 nm),anatase (μm) and natural anatase were investigated by Raman spectrum.The spectra indicate:when the crystalline particles sizes decreased,obvious Raman sh ifts towards higher frequencies were observed and the intensity of Raman scatter ing decreased markedly.The shift towards higher frequencies reached max (10 cm- -1) at 143 cm- -1 comparing 2 nm anatase and natural anatase;when th e crystalline particles sizes decreased;the shifts at 515 and 637 cm- -1 towards higher frequecies reached max,but while the crystalline particles sizes became smaller,the shifts reached towards lower frequencies;There was no obvious shift at 396 cm- -1 with the decreasing of the crystalline particle sizes .These reflect the complexity of nanophase materials structure,that may be cause d by flexibility distortion of crystal.