钛酸铋纳米晶的喇曼光谱和红外光谱研究

Raman and infrared spectroscopy studies on bismuth titanate nanocrystals

利用MOD方法制备了钛酸铋(Bi4Ti3O12(BTO))纳米晶.采用空间群结合晶格动力学分析了BTO晶体中的晶格振动模,理论预测了最多可能产生24个喇曼散射峰和28个红外吸收峰.喇曼散射和红外吸收实验结果与理论预测相比,峰数有大量减少.将此归因于谱带的叠合,某些谱线强度太弱,以及BTO晶体阴离子基团中TiO6八面体的存在等原因.对主要的喇曼峰和红外吸收峰采用TiO6八面体的内振动模进行指认,发现八面体的畸变程度很大,导致某些谱线产生了频移和劈裂.

Bismuth titanate （Bi4Ti3Oi2 （BTO）） nanocrystals have been successfully prepared by metal-organic decomposition. Raman scattering and Fourier-Transform infrared measurements of BTO nanocrystals show a large decrease of the number of peaks when compared to the space group theoretical analysis. It could be interpreted by the fact that the characteristic vibration modes of BTO nanocrystals arise mainly from the internal modes of TiO6 octahedra, which in return lead to modes degeneration. Raman shifts and infrared absorption bands of BTO nanocystals are tentatively assigned. The distortion of the octahedral leads some peaks to split or even shift to other positions.