Résumé
The response of noble metals to light changes dramatically when the size of the metal particles is reduced to the nanometer scale. The interaction of light with conduction electrons then results in coherent oscillations that can achieve resonance with certain electromagnetic frequencies. Such phenomena are called localized surface plasmon resonances (LSPRs), and can be finely tuned through the size and morphology of the nanoparticles, so that the whole visible and near-IR ranges can be covered. Exquisitely accurate synthetic methods have been devised toward the growth of metal particles with both spherical and anisotropic geometries, with narrow size distributions. Further tuning of morphological and optical properties can be achieved by post-synthesis chemical transformations, typically leading to morphological changes that offer advantageous application, e.g. in photothermal effects or surface enhanced spectroscopies.
In this talk we shall discuss some ideas regarding the combination of anisotropic seeded growth and post-synthesis transformations in metal nanoparticles, as well as some examples of their effects in different types of optical spectroscopy.
