SERS and DFT investigation on push-pull molecules: 4-Dimethylamino- 4’-nitrostilbene adsorbed on silver colloidal nanoparticles

The adsorption of 4-dimethylamino-4’-nitrostilbene, a typical push-pull chromophore, on Ag colloidal nanoparticles has been studied for the first time by SERS spectroscopy with different exciting lines and interpreted by the help of density functional theory calculations. This study allowed ascertaining the adsorption of DANS on silver via nitro-group and collecting information on the structural changes of the molecule induced by the interaction with the metal surface, leading to augmented nonlinear optical properties. In addition, under blue-green light irradiation the adsorbed molecules undergo a photoreduction of the nitro-group by a plasmon-induced catalyzing effect of the nanostructured silver surface.