Directed Synthesis and Doping of Wide Bandgap Semiconducting Oxide Nanocrystals
Nanoscience and Nanotechnology
Wide bandgap semiconducting oxide nanocrystals are a useful class of materials with high stability and numerous useful properties. In the field of catalysis, high surface area oxides are commonly used as catalytic supports and have been found to be photocatalytically active for the production of renewable fuels. Ultra high vacuum studies of single crystals indicate that the surface structure and faceting of oxides dramatically influence their catalytic properties. For plasmonics applications, degenerately doped oxide nanocrystals may act as low-loss substitutes for metals, but little is known regarding the influence of particle shape or assembly on their optical response. With the discovery of nonaqueous surfactant assisted synthesis, methods to produce nanocrystals which provide precise control over size, shape, and crystal structure have improved dramatically. On the other hand, exploration of the influence of morphology on the properties of many materials, including wide bandgap oxide materials, is only in its infancy. Herein, improved methods are described to control both the size and shape of semiconducting oxide nanocrystals. The influence of nanocrystal shape on the photocatalytic activity for hydrogen evolution and other environmentally relevant reactions is then described, as well as the shape dependent plasmonic response and dielectric properties of conductive oxide nanocrystals.