Abstract
M.Sc.
ZnO nanostructures with different morphologies have been prepared by using microwave and conventional heating methods. The effect of solvent, zinc precursor, time and the concentration of sodium hydroxide on the morphology of zinc oxide were investigated, when different heating methods were employed. ZnO nanoparticles were prepared using the solvothermal method. Zinc precursor impact on the shape of zinc oxide nanoparticles formed depends on the solvent used during the synthesis. Different morphologies such as spheres, rods, hexagonal prisms, hexagonal plates, diamond-like and multipods were formed by a simple solution based method. The optical features for most of the formed shapes were typical of ZnO nanoparticles. The XRD patterns of the particles showed the most stable hexagonal phase with a high degree of crystallinity. A capping molecule has an impact on the shape of the nanoparticle. In this work, we also present the results from the study of the effect of the stabilizing molecule on the shape and formation of the core shell nanoparticles of CdSe/PbS. The capping molecules used were hexadecylamine (HDA), tri-n-octylphosphine oxide (TOPO) and stearic acid. The core shell nanomaterials were synthesized by using a method in which selenium powder was converted to TOPSe.Transmission electron microscopy was used to determine the morphology and the size of the ZnO and coreshell nanomaterials. Spherical particles were obtained when TOPO was used whereas the use of HDA induced the formation of non-spherical shapes. With both capping molecules, epitaxial shell growth was not achieved. The particles formed from both capping groups (HDA and TOPO) were large due to the long reaction time that instigates lager particle sizes. However, when stearic acid was used as a capping molecule, a perfect core shell arrangement was formed. The phase and the crystallinity of the formed particles were determined by the XRD.