Colloidal carbon spheres and their core/shell structures with noble-metal nanoparticles.

Colloidal microand nanospheres have been of continuous research interest, since their intrinsic properties can be finely tuned by changing parameters such as diameter, chemical composition, bulk structure, and crystallinity. Up to now, they have found a broad range of applications in fields such as drug delivery, biodiagnostics, combinatorial synthesis, and photonic band-gap crystals (PBG). The success of these applications strongly depends on the availability of colloidal spheres with tightly controlled size and surface properties. However, until now, only amorphous silica and some colloidal polymer spheres can be routinely prepared with satisfactorily narrow size distributions. As-prepared colloidal nanoand microspheres usually have relatively inert surfaces, which make surface modification almost unavoidable before use as supports or templates.