title: Charge transfer process at the Ag/MPH/TiO2interface by SERS: alignment of the Fermi level.
abstract: A nanoscale metal-molecule-semiconductor assembly (Ag/4-mercaptophenol/TiO2) has been fabricated over Au nanoparticle (NP) films as a model to study the interfacial charge transfer (CT) effects involved in Ag/MPH/TiO2. Due to the interaction between Au NPs and Ag NPs, some distinct differences occur in the SERS spectra. We also measured the SERS of Ag/MPH (4-mercaptophenol), Ag/MPH/TiO2, and Au/Ag/MPH/TiO2assemblies at excitation wavelengths of 477, 514, 532, 633, and 785 nm. We found that the changes in the CT process, caused by the introduction of TiO2and Au, can be reflected in SERS. Then in combination with other detection methods, we proposed a possible CT process involved in the Ag/MPH, Ag/MPH/TiO2, and Au/Ag/MPH/TiO2assemblies. A Pt/Ag/MPH/TiO2assembly was also constructed to verify our proposed CT mechanism. This work not only provides more details about CT between metal-molecule-semiconductor interfaces but also aids in constructing nanoscale models to study interfacial problems with the SERS technique.
authors: State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun, P. R. China. zhaob@mail.jlu.edu.cn.
authors: Xiaolei
authors: X
authors: Zhang
authors: State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun, P. R. China. zhaob@mail.jlu.edu.cn.
authors: Huimin
authors: H
authors: Sui
authors: State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun, P. R. China. zhaob@mail.jlu.edu.cn.
authors: Xiaolei
authors: X
authors: Wang
authors: State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun, P. R. China. zhaob@mail.jlu.edu.cn.
authors: Hongyang
authors: H
authors: Su
authors: State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun, P. R. China. zhaob@mail.jlu.edu.cn.
authors: Weina
authors: W
authors: Cheng
authors: State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun, P. R. China. zhaob@mail.jlu.edu.cn.
authors: Xu
authors: X
authors: Wang
authors: State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun, P. R. China. zhaob@mail.jlu.edu.cn.
authors: Bing
authors: B
authors: Zhao