SERS spectroscopic characterization and analysis of the molecular structure of linkage monolayers in assembled gold nanoparticle films

Abstract

Molecular assembly was used to prepare a 4,4'-dithiodipyridine (PySSPy) self-assembled monolayers (SAMs) modified gold electrode. The prepared PySSPy SAMs modified on gold electrode were then used as linkage monolayers to fabricate gold nanoparticle assembled films. In our research, surfaceenhanced Raman scattering (SERS) technique was used to investigate the structural characteristics of the linkage monolayers. Moreover, electrochemical in situ SERS spectroscopy was used to characterize the effect of electrode potential on the molecular structure of this linkage monolayer. An analysis of the regular variations in intensities and shifts of the characteristic Raman peak pairs related to the adsorbed molecules in this linkage monolayer, such as at 1011 and 1093 cm-1, 1575 and 1610 cm-1, 1206 and 1215 cm-1, revealed that the aromaticity of the pyridyl ring groups in the linkage monolayer changed with the applied electrode potential. The results show that the adsorbed molecule exists mainly in the form of a thiol tautomer in the negative potential range while it exists mainly in the form of a thione tautomer in the positive potential range. © Editorial office of Acta Physico-Chimica Sinica.