Formation and characterization of gold and silver nanoparticles on silica nanospheres

Novel optical effects are expected by appropriately arranging metal nanoparticles on the surface of spherical insulating materials. Optical resonances of this nanostructures from near infrared to the visible range may be tuned by adjusting the oxide size, size of the metal particles and the filling factor. For a better control of the optical properties of such composite materials the best choice as oxide material is the monodisperse oxide particles. Water-soluble metal precursor complexes hydrogentetrachloroaurate and silver acetate have been employed. The optical properties of these materials correspond to their overall structure of nanoparticulate composites having a very low filling factor of the metal phase.