Paper NS-TuP16
Template-Free Synthesis and Characterization of Copper Oxide Nanostructures

Tuesday, October 21, 2008, 6:30 pm, Room Hall D

As a relatively non-toxic p-type semiconductor and a classical example of excitonic solid, cuprous oxide may play an important role in the electronics industry as the dimensions of electronic devices continue to shrink. For example, devices made of nanometer-scale cuprous oxide are expected to be small and fast because the electrical signal can resonantly tunnel through the nanoscale cuprous oxide layers. In addition, cuprous oxide structures fabricated in the nanoscale may exhibit better antifouling and algicide effects, increase its overall water splitting capability for solar energy applications, and enhance its photocatalytic activity for degradation of organic pollutants under visible light. Nanoscale cuprous oxide structures were prepared in this study via a template-free synthetic approach in the ethylene glycol solution using different copper compounds as the precursor. SEM images and Auger spectra revealed that, instead of forming spherical particles, micro- to nano-sized aggregates of well-defined geometric shapes were obtained. These aggregates were made of nanocrystalline particles, as revealed in high-resolution TEM and diffraction studies, which self-assembled into organized solids. XPS spectra suggested that the crystallization and the self-assembling may take place via cuprophilic attraction. The shape and the dimensionality of the assemblage obtained can be controlled by adjusting reaction temperature and/or by using different surfactants. Chemical conversion of cuprous oxide to cupric oxide impaired the cuprophilic interaction, leading to dismantling of the assemblage at extended reaction time. The chemical process and the mechanism involved in the assembling and dismantling of the polycrystalline assemblage will be discussed.