2.14 - Nanostructured Inorganic–Organic Hybrid Semiconductor Materials

Abstract

This chapter offers an overview on the recent development of novel inorganic–organic hybrid semiconducting materials that are built on binary MxQy (M=metal, Q=group VI element) semiconductor modules and organic molecules via self-assembled solution synthesis. The sub-nanometer-sized semiconductor motifs (inorganic component, e.g., II–VI and III–VI) and acyclic or cyclic amine molecules (organic component, e.g., ethylenediamine and m-xylylenediamine) are arranged into perfectly ordered one-, two-, and three-dimensional extended network structures. Incorporation of organic and inorganic components into a single crystal lattice has led to a number of integrated and enhanced properties over their parent semiconductor bulk (e.g., significantly larger absorption coefficients and reduced thermal conductivity), as well as unique phenomena and new functionality that are not possible with either individual constituent alone (e.g., direct white light emission from a single material without complex mixing/doping and nearly zero thermal expansion behavior). More significantly, the hybrid semiconductors exhibit a structure-induced (rather than a size-induced) quantum confinement effect (QCE), a fundamentally distinct property that has not been reported on any other types of nanomaterials. The extent of such a structure-induced QCE is exceptionally strong and leads to a very broad bandgap tunability. In addition, the electronic and optical properties of these hybrid semiconductors can be systematically tuned by modifying their crystal structure, composition, and dimensionality of the inorganic motifs.