Surface-enhanced Raman scattering of 4-aminothiophenol in assemblies of nanosized particles and the macroscopic surface of silver

Assemblies consisting of nanosized silver particles, 4-aminothiophenol, and the smooth macroscopic surface of silver metal (Ag/PATP/Ag) were prepared and characterized by surface-enhanced Raman spectroscopy. The Raman spectrum of 4-aminothiophenol in the assemblies is similar to that obtained on the electrochemically roughened electrode, although spectral differences, including slight frequency shifts and changes in relative intensity of the characteristic bands, were observed. The enhancement of the spectrum of 4-aminothiophenol in the assemblies is ascribed to the electromagnetic coupling between the silver particles and the surface of the silver metal. The fact that only the SERS spectrum of 4-aminothiophenol was observed for the assembly, where 4-aminothiophenol is partially replaced with N,N'-diphenylthiourea, demonstrates that the electromagnetic field is mainly localized in the region between the silver particles and the surface of the silver metal.