Silver Nanostars with High SERS Performance

We report in this work the fabrication, for the first time, of silver nanostars (AgNS) by a simple new method consisting of the chemical reduction of Ag+ by neutral hydroxylamine, followed by a capping–reduction process induced by citrate. TEM and SEM were employed to study the morphology of the resulting nanoparticles, which exhibit a star-shaped morphology with a central particle provided with several arms or protuberances with low sharpness in the vertices. Dark field microscopy was employed to study the scattering emission of individual nanostars indicating the increasing presence of nanoparticles with scattering emission toward the red region. AgNS displayed a high performance in surface-enhanced Raman scattering (SERS) applications. The effectiveness of these nanoparticles was probed by using the drug probenecid, leading to intense SERS spectra without the addition of aggregation agents.