Optical properties of metallic nanoshell composites: The effects of temperature and particle clustering

The optical properties of a metallic nanoshell composite are studied theoretically using different effective medium theories with particular focus on the effects of variation in temperature and particle clustering on these properties. One unique result from our modeling is the persistent manifestation of the single-particle resonances of the individual nanoshells which cannot be found in a composite of solid particles. In addition, we observe red-shifts in the composite plasmon modes, as well as damping in the dielectric function spectrum as the temperature increases. Furthermore, a much greater red-shift will occur when these nanoshells coalesce to form fractal clusters in the composite, with the value of this shift increasing with decrease in the fractal dimension or increase in the cluster size. We further calculate the transmission at normal incidence through such composite thin films as a demonstration of how these effects can be observed experimentally. © 2009 Elsevier Ltd. All rights reserved.