Synthesis of silver nanoparticle arrays for SERS based sensing

Abstract

Recently, noble-metal nanoparticles (NMNPs) were introduced in the sensing discipline, and become one of the most efficient ways to enhance sensors sensitivity. It is known, in fact, that NMNPs possess peculiar optical properties. When NMNPs are illuminated by a laser beam with proper wavelength, the so-called localized surface plasmons, a collective oscillation of conduction electrons on NMNP surface, are excited. The effect is relevant, for example, in Surface Enhanced Raman Spectroscopy, where a significant enhancement of a localized electromagnetic field near NMNPs surface allows to detect species usually undetectable with normal Raman spectroscopy. Here we present a method for the growth of silver NP arrays with controlled morphology by means of the pulsed laser ablation technique performed in presence of a Ar atmosphere. The nanoparticles size and morphology can be tuned, respectively, by the Ar pressure and the laser pulse number. The SERS activity of nanoparticle arrays is investigated by Raman scattering of adsorbed rhodamine 6G (R6G) at different concentrations. © 2011 Springer Science+Business Media B.V.