Computational Matching of Surface Plasmon Resonance: Interactions between Silver Nanoparticles and Ligands

Abstract

A multilayer model of a single coated nanoparticle has been refined through finite elements method based simulations and resulted in a successful matching of the experimental UV–visible spectra of ligand-coated silver nanoparticles. The computational matching of the surface plasmon resonance (SPR) band reveals both a ligand-type dependence of the effective plasma frequency and a size dependence of the SPR damping effect within the modeled nanoparticle. The observed differences of effective plasma frequency between thiol and amine-coated nanoparticles are consistent with the already known stronger bonding of thiols on silver compared to amines. The significant increase of the damping effect at the surface of the nanoparticle when increasing their size suggests an inverse relation between the ligand packing density and the nanoparticle size, which is supported by the expected influence of the surface curvature radius on the ligand packing