Aqueous Solution Synthesis, Characterization, And Optical Property Of Zinc Oxide Nanomaterials With Polyoxometalates

ZnO is one of the most important wide -band-gap II-IV semiconductors. Its considerable applications in optical, optoelectonic, conductor, gas sensor and biology have initiated intensive research. ZnO nanomaterials are a kind of inorganic functional materials with special properties compared with buld ZnO. Physical and chemical methods are two main methods for the fabrication of ZnO nanomaterials. Thereinto, solution chemical methods have proven to be appealing because of their mild reaction temperature, simply manipulation and large scale-up production.In this dissertation, various morphologies of ZnO nanomaterials have been fabricated through solution chemical method by controlling the reaction conditions. The main contents are listed below:(1) Uniform ZnO hollow nanospheres were fabricated controllably by using cheap zinc foils a simply one-step, polyxometalate-assisted, electrochemical mthod. Reasonable mechanisms were also discussed to explain the results in detail. The photocatalytic investigation indicated that the as-prepared ZnO hollow nanospheres had good photocatalytic activity. Furthermore, with the help of polyxometalate, single crystalline ZnO with the morphologies, including nanorods, nanosheets and nanobundles were successfully obtained by hydrothermal method. At the same time, the optical properties of the ZnO nanostructures have also been discussed.(2) An alcohol thermal process was developed of the controllable syntheses of ZnO nanorods, nanoparticles and starlike nanocrystals at a low temperature. The effect of the surfactant to the morphologies of the ZnO nanostructures has also been discussed. Furthermore, growth of uniform ZnO nanoparticles from a nanowhisker precursor was realized with a simple solvothermal route. An attractive template-free hydrothermal method was developed to synthesize ZnO nanotubes. The effect of the reaction time to the morphology of the ZnO nanotubes has also been discussed.(3) A novel reaction was developed for the synthesis of ZnO nanoparticles with nearly uniform spherical morphology by directly oxidizing zinc powders with iodine in ethanol. The effect of iodine during the reaction has also been researched. Furthermore, facile synthesis of ZnO nanoparticles in polyelectrolyte multilayer films was presented using the in situ layer-by-layer nucleation and growth method. The morphologies of the particles were controlled from the nanoparticles to the one dimensional nanocrystals through changing the precipitation reaction cycles.