Wang Yaxin, Yan Chao, Li Chunxiang, Lu Ziyang, Ma Changchang, Yan Yongsheng, Zhang Yongjun
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, China.
Zhonggong Education and Technology Co., Ltd., Changchun 130000, China.
Nanomaterials (Basel). 2018 Dec 7;8(12):1019. doi: 10.3390/nano8121019.
TiO₂/Ag bilayer films sputtered onto a 2D polystyrene (PS) bead array in a magnetron sputtering system were found to form a nanocap-shaped nanostructure composed of a TiO₂-Ag composite on each PS bead, in which the Ag nanoparticles were trapped partially or fully in the TiO₂ matrix, depending on the TiO₂ thickness. X-ray Photoelectron Spectroscopy (XPS) results showed the opposite shifts of binding energy for Ti 2p and Ag 3d, indicating the transfer of electrons from metallic Ag to TiO₂ owing to the Ag-O-TiO₂ composite formation. UV-Vis absorption spectra showed the blue shifts of the surface plasma resonance peaks, and the maximum absorption peak intensity was obtained for TiO₂ at 30 nm. The surface-enhanced Raman scattering (SERS) peak intensity first increased and then decreased when the TiO₂ thickness changed. The observations of SERS, XPS, and UV-Vis absorption spectra were explained by the dependency of the charge-transfer process on TiO₂ thickness, which was ascribed to the changing dielectric properties in the metal/semiconductor system.
通过磁控溅射系统溅射在二维聚苯乙烯（PS）微珠阵列上的TiO₂/Ag双层薄膜，被发现会在每个PS微珠上形成由TiO₂-Ag复合材料组成的纳米帽状纳米结构，其中Ag纳米颗粒根据TiO₂的厚度部分或完全被困在TiO₂基质中。X射线光电子能谱（XPS）结果显示Ti 2p和Ag 3d的结合能发生相反的位移，表明由于形成了Ag-O-TiO₂复合材料，电子从金属Ag转移到了TiO₂。紫外-可见吸收光谱显示表面等离子体共振峰发生蓝移，并且在TiO₂为30 nm时获得了最大吸收峰强度。当TiO₂厚度变化时，表面增强拉曼散射（SERS）峰强度先增加后降低。SERS、XPS和紫外-可见吸收光谱的观测结果通过电荷转移过程对TiO₂厚度的依赖性来解释，这归因于金属/半导体系统中介电性质的变化。
