Means and Limits of Control of the Shell Parameters in Hollow Nanoparticles Obtained by the Kirkendall Effect

Recently reported synthetic routes for the production of hollow nanoparticles have stimulated significant interest for the possibilities this novel geometry offers. While advantageous properties have been found and innovative applications have been proposed, the development of the full potential of these new nanostructures is still strongly tied to the extent of control that can be accomplished over their characteristics (e.g., composition, size, shell thickness, and nanocrystalline structure). In the present work, we investigate the means and limits of control over these parameters that can be obtained by the Kirkendall effect synthetic route on cadmium chalcogenide nanocrystalline shells. We demonstrate that the selection of the reactants and oxidation conditions allows some extent of control of the nanocrystalline structure and thickness of the shell. However, the tuning range is limited by the intrinsic restrictions of the synthetic procedure and by the dependence of the particle geometry on the same reaction conditions. Thus, we further explore the range of control over the shell parameters that can be accomplished through post-synthesis processes, such as chemical etching and thermal annealing.