Controlled synthesis and luminescence of semiconductor nanorods.

A variety of nearly monodisperse semiconductor nanocrystals, such as CdS, ZnS, and ZnS:Mn, with controllable aspect ratios have been successfully prepared through a facile synthetic process. These as-prepared nanocrystals were obtained from the reactions between metal ions and thioacetamide by employing octadecylamine or oleylamine as the surfactants. The effects of reaction temperature and time, ratios of thioacetamide to inorganic precursors, and the reactant content on the size and crystal purity of the nanorods, have been systematically investigated. The optical properties and the formation mechanism of the nanorods have also been discussed. For the next biolabel applications, these hydrophobic nanocrystals have also been transferred into hydrophilic colloidal spheres by means of an emulsion-based bottom-up self-assembly approach.