Optical Properties of Self-Assembled 2D and 3D Superlattices of Silver Nanoparticles

Abstract

In this paper we compare the optical properties of nanosized silver particles dispersed in hexane solution and self-assembled in a 2D or 3D network. When the particles form monolayers organized in a hexagonal network, the plasmon peak of silver nanosized particles is shifted toward lower energy, with an increase in bandwidth compared to that observed with free coated particles dispersed in hexane solution. Such a shift is attributed to an increase in the dielectric constant of the matrix environment of the nanoparticles. When the particles form a 3D superlattice with a face-centered cubic (fcc) structure, the optical properties could be interpreted as an increase in the mean free path of the conduction electrons, which could indicate the presence of tunneling electrons across the double layers due to the coating of the particles.