(763a) Size and Shape Engineering of ZnO Nanoparticles

The investigation of ZnO nanoparticles is of great interest due to the wide range of potential applications for this material. Despite this, a thorough understanding of the optical, electronic and structural properties of ZnO nanoparticles with respect to their synthesis is still lacking. We tackled this problem by synthesizing ZnO nanoparticles with nanocrystal, nanorod and self-assembled aggregate form using ambient and hydrothermal wet chemical processes. Dynamic light scattering, absorption and emission spectroscopies, thermogravimetric analysis, X-ray powder diffraction, Fourier infrared spectroscopy as well as transmission and scanning electron microscopies were employed to characterize and compare the nanoparticles composition, their shape, size and crystallinity. By varying different parameters of the synthesis processes like precursors and their concentrations, solvent used, surfactant, temperature, and reaction time we were able to control the size and shape of the particles. In particular we noted the tendency of ZnO nanocrystals to self-assemble into dense structures which preserve the anisotropic crystal structure. Using surface-mediating polymers such as PVP, this self-organisation could be modified so as to produce nanostructures with a tunable porosity, with great potential for application.