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Generation of Pronounced Resonance Profile of Charge-Transfer Contributions to Surface-Enhanced Raman Scattering

NCJ Number
Journal of Physical Chemistry C Volume: 116 Issue: 3 Dated: 2012 Pages: 2515-2520
Date Published
6 pages

This article reports on an assessment of a chemically enhanced mechanism of surface-enhanced Raman scattering (SERS), using a series of metal-charge-transfer (CT) complex systems fabricated by a self-assembly method.


The developed Ag/4-mercaptophenols (MPH)/n-TiO2 system presented layer number-dependent SERS spectra. By using the electron density values of the Ag13/MPH and Ag13/MPH/TiO2 system calculated using the density functional theory (DFT) and by using these values in combination with the results of the authors ‘ previous investigations on the mechanism of the Ag/MPH/TiO2 system, the absorption threshold of the CT complexes was clearly defined. The degree of CT was selected to study the layer number-dependent SERS spectra. Based on the layer number-dependent SERS data, it has been inferred that the degree of CT represents a resonance phenomenon. In addition, the CT resonance occurs at higher energy in the Ag/MPH/n-TiO2 system than in the monolayer TiO2 system owing to the blue-shift of CT states with the continuous introduction of TiO2. Thus, this project provides a good example of the use of a CT complex system to investigate the chemical mechanism of SERS. (publisher abstract modified)

Date Published: January 1, 2012