The effects of interparticle distance on the UV-visible absorption spectrum of gold nanocrystals aggregates in aqueous solution have been investigated. The aggregates were produced by ion-templated chelation of omega-mercaptocarboxylic acid ligands covalently attached to the nanoparticles surface. Variation of the ligand chain length provides control over the interparticle separation in the aggregates. The UV-visible spectra consist typically of a single particle band and a secondary band at higher wavelengths associated with the formation of aggregates in solution. The position of the latter depends on interparticle separation up to distances of similar to 8 nm, in accordance with existing models. Potential applications therefore include distance sensitive labels or proximity probes. Conversely, variation of the ligand length allows the preparation of nanostuctured materials with tuned optical properties.
|Journal||Physical Chemistry Chemical Physics|
|Publication status||Published - 2006|