1 research outputs found
Laser-Induced Reactions of 4‑Aminobenzenthiol Species Adsorbed on Ag, Au, and Cu Plasmonic Structures Followed by SERS Spectroscopy. The Role of Substrate and Excitation Energy – Surface-Complex Photochemistry and Plasmonic Catalysis
This study focuses
on investigating the laser-induced reactions
of various surface complexes of 4-aminobenzenethiol on Ag, Au, and
Cu surfaces. By utilizing different excitation wavelengths, the distinct
behavior of the molecule species on the plasmonic substrates was observed.
Density functional theory (DFT) calculations were employed to establish
the significant role of chemical enhancement mechanisms in determining
the observed behavior. The interaction between 4-aminobenzenethiol
(4-ABT) molecules and plasmonic surfaces led to the formation of surface
complexes with absorption bands red-shifted into the visible and near-infrared
regions. Photochemical transformations were induced by excitation
wavelengths from these regions, with the nature of the transformations
varying based on the excitation wavelength and the plasmonic metal.
Resonance with the electronic absorption transitions of these complexes
amplifies surface-enhanced Raman scattering (SERS), enabling the detailed
examination of ongoing processes. A kinetic study on the Ag surface
revealed processes governed by both first- and second-order kinetics,
attributed to the dimerization process and transformation processes
of individual molecules interacting with photons or plasmons. The
behavior of the molecules was found to be primarily determined by
the position and variability of the band between 1170 and 1190 cm–1, with the former corresponding to molecules in the
monomer state and the latter to dimerized molecules. Notably, laser-induced
dimerization occurred most rapidly on the Cu surface, followed by
Ag, and least on Au. These findings highlight the influence of plasmonic
surfaces on molecular behavior and provide insights into the potential
applications of laser-induced reactions for surface analysis and manipulation