Synthesis Of Copper Chalcogenides And Their Properties

Metal oxides and semiconductor nanomaterials have become one of importantresearches in fields of materials, chemistry and physics etc. because of their excellentproperties in catalysis, optics, photoelectric conversion, gas sensitivity and magnetism. Due tothe structure, composition, crystal structure, morphology and size of materials influence theperformance and applications of the materials, designing and controlling synthesis ofcopper oxides and copper selenide semiconductor materials with a specific structure andmorphology are of significance from theortical and practical point of view. In this thesis theporous square-brick-like hierarchical CuO was synthesized by ultrasound and microwaveassisted method, combing with thermal conversion reaction. The nanorod and nanosheethierarchical CuO microspheres and hexagonal Cu2-XSe microplates were preparedunder mild hydrothermal conditions. The detailed structure and morphology characterizationand optical properties of the synthesized micro/nano materials were studied. The effect ofdifferent reaction conditions on the morphology was explored and discussed. This thesisincludes the following aspects:1. Using low cost SDBS as a directing agent, CuCl₂·2H₂O and K₂C₂O₄as the rawmaterials, square-brick CuC₂O₄.xH₂O precursor were synthesized by ultrasound-microwavemethod. After calcination of the CuC₂O₄.xH₂O precursor at 300℃, the square-brick porousCuO materials were fast obtained. The crystal structure, morphology and particle size of theproducts were characterized by XRD, SEM and TEM, and the elementalcomposition and purity of the products were studied by XPS, the surface area and pore sizedistribution of the products were obtained by N2adsorption - desorption experiments.The surface structure, absorption and fluorescence properties of the products were studied byFT-IR, UV-Vis absorption spectra and PL. The surface photovoltaic property of the productwas also studied. In addition, effect of different reaction conditions on the morphology wasdiscussed and the formation mechanism of square-brick porous CuO materials was proposed.2. CuO microspheres with a nanorod-like hierarchical structure were synthesized by mildhydrothermal method in a water-ammonia system, where CuCl₂·H₂O was used as the rawmaterial and non-toxic water soluble SDBS as a directing agent, the dependence of CuOmicrosphere morphology on reaction conditions was investigated. The crystal structure,morphology and particle size of the products were characterized by XRD, SEM and TEM,and the surface area of products were obtained by N2adsorption-desorption experiments.The surface structure, absorption and fluorescence properties of the products were studied byFT-IR, UV-Vis absorption spectra and PL. It was found that the amount of SDBS andammonia plays an important role on formation of spherical CuO by self-assemble ofnanorod-like structures. Moreover, CuO microspheres with a hierarchical nanosheet-like structure were synthesized by mild hydrothermal method in a water-ammonia system at lowtemperature.3. Hexaonal Cu_2-xSe microplates were synthesized by mild hydrothermal method in awater-NaOH-N2H4·H2O system, where selenium power and CuCl₂·H₂O were used as the rawmaterials and OLA as a directing agent. The crystal structure, morphology and particle size ofthe products were characterized by XRD, SEM and TEM. The effect of differentreaction conditions on the morphology was also discussed and the formation mechanism ofhexaonal Cu_2-xSe microplates was proposed. The surface structure, absorption andfluorescence properties of the products were studied by FT-IR, UV-Vis absorption spectraand PL, the p surface hotovoltaic properties of the products was also studied.