Relation between the photoreaction of p-nitrobenzoic acid onto silver-coated filters and the surface roughness, as detected by SERS and AFM

The SERS of p-nitrobenzoic acid has been first obtained in Ag hydrosol and compared with those deriving from filtration of colloidal silver. The roughness of the Ag-coated filters has been examined by AFM measurements and related to the SERS enhancement. The addition of chloride anions to the colloidal suspension strongly increases the surface roughness of the solid metal substrates and activates the photoreaction of the adsorbate by irradiation with green laser light.