Stability of core-shell nanoparticles formed in a dielectric medium

We report the time evolution of declustering phenomenon of metal nanoclusters of size less than 2 nm grown in a glassy medium. The clusters are found to be of core shell in structure and the shell formation is inevitable and accompanied by the clusters of such smaller size. Clusters having two different size distributions are grown during the aging period of the sample showing surface plasmon resonant (SPR) absorptions peaked at the wavelengths similar to 460 and similar to 600 nm. We explain the formation of secondary clusters and the cluster decay process based on the SPR of silver clusters formed in an ion-exchanged silicate glass using a generalized Mie scattering theory and a supporting thermodynamic description. (C) 2007 American Institute of Physics.