Solution-based Synthesis And Properties Of Znic Oxide And Zinc Sulfide Nano/micromaterials

Nanostructured metal oxides and sulfides have exhibited promising applications in many fields due to their unique physical and chemical properties. Previous studies suggest that the morphology, size, dimensionality and structure of nanomaterials directly influence their properties. Thus it is of great importance to control the morphology, size, dimensionality and structure of nanomaterials and further realize the artificial tailoring of their properties, and clearly understand the relationship between structure and properties of nanomaterials. In this thesis, hydrothermal synthetic methods have been developed to prepare zinc oxide and zinc sulfide nano/micromaterials. In addition, the formation mechanism and optical properties of final products have been carefully investigated. The content is summarized as follows:(1) Flower-like ZnO microstructures built of nanorods have been successfully synthesized via a facile hydrothermal method under mild conditions. The influences of hydrothermal temperature, reaction time, and concentration of reactants on the morphology and size of final products have been carefully investigated. The formation mechanism of flower-like ZnO microstructures has also been proposed. TEA has been found to act as both complexing reagent and alkaline reagent. In addition, the PL properties of final products have been examined and it is found that flower-like ZnO built of nanorods exhibits unique PL emission properties.(2) The influences of different kinds of inorganic and organic salts on the morphologies of ZnO nano/micromaterials prepared via a facile hydrothermal route have been investigated. It is found that the introduction of different kinds of salts can effectively control the morphologies and size of ZnO nano/micromaterials. The possible mechanism for the phenomenon has been proposed. The PL properties of final products have been studied. The dependence of PL properties on morphologies and size of final products has been clearly observed.(3) ZnS nanotubes have been successfully synthesized via a facile conversion process from ZnO nanorods precursors. During the conversion process, ZnO nanorods are first prepared as sacrificial templates and then converted into tubular ZnO/ZnS core/shell naonocomposites through a hydrothermal sulfidation treatment. ZnS nanotubes are finally obtained through the removal of ZnO cores of tubular ZnO/ZnS core/shell naonocomposites by KOH treatment. The influences of molar ratio of reactants on the morphology and structure of final products have been investigated. A diffusion and consumption process was proposed to explain the formation of ZnO/ZnS core/shell nanocomposites. The UV-vis and PL properties of products have been studied. This strategy may provide more opportunities for the preparation of core/shell structured and hollow metal chalcogenides.