Template-Free Synthesis and Assembly of Single-Crystalline Tungsten Oxide Nanowires and their Gas-Sensing Properties

摘要

The controlled synthesis and characterization of crystalline objects with reduced dimensionality is a fascinating objective in modern materials science, physics, and chemistry. One-dimensional systems such as nanowires and nanotubes are especially attractive building blocks for nanodevices because they represent the smallest dimension for efficient transport of electrons and excitons.[1] A wide variety of synthetic methodologies, ranging from vapor-phase techniques to solution-growth processes, have been used to produce nanowires of elements, oxides, nitrides, carbides, and chalcogenides.[2], [3] Although transition metal oxides are an important class of materials,[4] soft-chemistry routes to crystalline metal-oxide nanowires under mild reaction conditions are not yet available. The reason for this is that sol-gel derived materials formed at low temperature are amorphous, and that the heat treatment necessary to induce crystallization is usually accompanied by an undesired alteration of the particle morphology.