SERS effect from silver photoreduced on to silica colloidal nanoparticles

Abstract

Novel SERS-active substrates were obtained by photoreduction of silver ions on to silica nanoparticles dispersed in aqueous solution. By adsorption of organic ligands the Ag-doped silica colloids show good stability and SERS efficiency comparable to those of pure silver hydrosols.

SERS investigation on the adsorption and photoreaction of 4‐nitroanisole in Ag hydrosols

“…As a conclusion, the first requisite for obtaining reliable and reproducible SERS results is to provide a valid procedure to obtain Ag colloidal systems with both stability and SERS activity. Silica or alumina could be employed as support of silver nanostructures in order to increase the stability of the colloidal suspensions . However, even if these materials are SERS inactive, spectral interferences with the SERS bands of the adsorbed molecules are possible.…”

“…Silica or alumina could be employed as support of silver nanostructures in order to increase the stability of the colloidal suspensions. [17][18][19][20][21] However, even if these materials are SERS inactive, spectral interferences with the SERS bands of the adsorbed molecules are possible. In the present study, a small amount of LiCl is introduced under continuous stirring in the Ag colloidal dispersions obtained by reduction of silver ions with borohydride, according to the procedure described in the experimental.…”

A nanoengineered sensor to detect vibrational modes of warfare agents/explosives using surface-enhanced Raman scattering

“…A number of FON type SERS substrates have previously been reported in the literature. [15][16][17][18][19] In some cases, remarkably low levels of analytes have been detected by these systems. We also show a highly sensitive SERS substrate; but more importantly, we demonstrate that the sensor can repeatedly detect a given concentration with the same signal response.…”

SERS‐active Ag/SiO2 colloids: photoreduction mechanism of the silver ions and catalytic activity of the colloidal nanoparticles

“…In this study, the formation of silver clusters on silica colloidal nanoparticles in aqueous suspension was achieved by laser irradiation and studied by means of UV-visible absorption and SERS spectroscopy in order to clarify the photoreduction mechanism of the silver ions. These Agdoped silica colloids are efficient SERS substrates for the detection of organic ligands 6 and can be employed in the investigation of the adsorption phenomena of different molecules. 7 In particular, the availability of these substrates allows the study of catalytic reactions on surfaces.…”