Fabrication of silver nanoparticles from silver salt aqueous solution at water-glass interface by visible CW laser irradiation without reducing reagents

Abstract

Abstract We have investigated the excitation wavelength and intensity dependencies of fabrication of silver nanoparticles (Ag NPs) on a glass substrate through the laser-induced photoreduction of silver ions in aqueous solution. It was found that the nucleation of Ag NPs could occur not in an aqueous solution of silver nitrate but at a water-glass interface without any reducing reagents. The nucleation could be triggered by photoexcitation at visible to Near-IR wavelength regions where the silver nitrate solution has no absorption band. From the excitation wavelength dependence using five CW lasers at 325, 442, 532, 690, and 1064 nm, it has been presumed that one-photon absorption of unique surface chemical species such as silver oxide (Ag 2 O) on the glass substrate is responsible for the reaction leading to the nucleation. Numerical simulation of a single Ag NP and a Ag@Ag 2 O core-shell NP on the basis of Mie theory revealed the photoproducts consists of Ag, but not Ag 2 O.