Synthetic strategies to size and shape controlled nanocrystals and nanocrystal heterostructures

The recognition of the strongly dimensionality-dependent physical-chemical properties of inorganic matter at the nanoscale has stimulated efforts toward the fabrication of nanostructured materials in a systematic and controlled manner. Surfactant-assisted chemical approaches have now advanced to the point of allowing facile access to a variety of finely size- and shape-tailored semiconductor, oxide and metal nanocrystals (NCs) by balancing thermodynamic parameters and kinetically-limited growth processes in liquid media. While refinement of this synthetic ability is far from being exhausted, further efforts are currently made to provide NCs with higher structural complexity as means to increase their functionality. By controlling crystal miscibility, interfacial strain, and facet-selective reactivity at the nanoscale, hybrid NCs are currently engineered, which consist of two or more chemically different domains assembled together in a single particle through a permanent inorganic junctions. In this chapter, we will review the strategies that have been so far developed for the synthesis of colloidal nanostructures, ranging from mono-material NCs with tailored dimensions and morphology to multi-material NC heterostructures with a topologically controlled composition.