Photochemical characteristics of silver 4-aminobenzenethiolate; Laser-induced growth of silver nanoaggregates probed by Raman spectroscopy

Abstract

Silver 4-aminobenzenethiolate (Ag-4ABT) is one of the organic - inorganic heterostructured. materials that show a well-developed progression of intense X-ray reflections associated with an infinite-sheet, twodimensional, nonmolecular layered structure, possessing also peculiar photochemical characteristics. When visible lasers are exposed to Ag-4ABT salt, its Raman spectrum changes with time, eventually becoming the same as the surface-enhanced Raman scattering (SERS) spectrum of 4-aminobenzenethiol (4ABT) adsorbed on a roughened Ag substrate. The growth of Raman peaks of Ag-4ABT salt was monitored as a function of laser exposure time as well as laser power and wavelength. It was analyzed in terms of the symmetry types of the vibrational modes of 4ABT, and greatly enhanced b2 vibrational bands were observed in the spectra caused by the strong contribution of chemical enhancement. The signal enhancement by the exposure of the visible lasers can be attributed to the presence of SERS-active Ag nanoparticles produced by the photoreaction of Ag-4ABT salt.