Synthetic architecture of interior space for inorganic nanostructures

One of the major technological challenges in nanoscience and nanotechnology is the self-assembly of tiny nano-building units (e.g., nanokits and nanoparts) into larger (i.e., mescoscale or microscale) organized conformations and geometrical architectures for device applications. To meet the requirements of new applications, an interior space for the nanostructures may be further required. When coupled with chemical functionality of boundary materials, the interior "nanospace" of the nanostructures possesses both aesthetic beauty and scientific attraction. For example, in addition to well studied core-shell nanostructures, there has been increasing research interest in the fabrication of hollow inorganic nanostructures owing to their potential applications in optical, electronic, magnetic, catalytic and sensing devices ranging from photonic crystals to drug-delivery carriers and nanoreactors. In this feature article, we report our recent research progress in this emerging field; our research is concentrated on the exploration of various novel organizing schemes through which interior spaces with architectural design can be created for inorganic nanostructures. These template-free "one-pot" synthetic methods include "oriented attachment", Ostwald ripening and Kirkendall effect etc. for direct solid evacuation under mild reaction conditions. Future research directions will also be addressed in this article.