Controlled nucleation, growth, and kinetics in ZnO hierarchical nanosyntheses
by Tian, Z. Ryan; Zhang, Tierui; Keeter-Brewer, Mary; Anderson, Quincy; Njabon, Roland N.
The optoelectronic, piezoelec., and chem. properties of ZnO nanomaterials are determined by the morphologies and spatial organizations of the ZnO nanostructures. Here we report a low-temperature, hydrothermal route to hierarchical fabrications of ordered and oriented ZnO complex nanostructures on substrates via controlling the sequential heterogeneous nucleation and growth processes, which is proved by the XRD and SEM studies. By inducing site-specific nucleation and thereafter directional growths of secondary and tertiary nanostructures, we have generated new hierarchical complex ZnO nanostructures with unique application potentials in, for instance, photocatalysis, solar cell, UV lasing, and nanotherapeutics. Roles of the type and concentration of the nucleation directing agent, reaction temperature, nucleation time, and growth kinetics in the solution hierarchical nanosyntheses have been systematically investigated for demonstrating a new bottom-up strategy for rational designs and precise fabrications of new hierarchical types of solid-state functional materials.