表面修饰的钛酸钡的拉曼光谱

Blue shift of Raman peaks of coated BaTiO_3 nanoparticles

采用水热法制得表面包裹有十二烷基苯磺酸(DBS)和硬脂酸(St)的BaTiO3纳米粒子,平均粒径均为60nm左右.拉曼光谱检测结果表明,样品的确为表面包裹有表面活性剂(DBS或St)的BaTiO3纳米粒子集合体.与未包裹的相比,各光学声子模对应的拉曼振动模式峰均发生了蓝移.还发现不同的包裹体,所导致的蓝移值也不同.从纳米粒子的表面结构及包裹层的压力出发对此现象进行了定性解释和讨论.

Nanosized BaTiO3 coated with dodecybensulphonic acid （DBS） and stearic acid （St） was prepared using the hydrothermal procedure. The average size of DBS/BaTiO3 and St/BaTiO3 is about 60nm, much smaller than the that of 100nm of the uncoated particles prepared under similar conditions. Raman spectra from the coated particles were measured, and scattering signals from both BaTiO3 and the coatings were observed. It was found that the Raman peaks of BaTiO3 shift toward higher frequency（blue shift）, instead of the red shift generally observed when the particle size is reduced, and the linewidth increases when the grain is coated. Meanwhile, we found that different coating show different amount of Raman shifts. We discussed the possible origin of the blue shift.