Fabrication And Microstructure Characterizations Of CuBiS₂ And Cu₃BiS₃ Nanostructures

In recent years, the wide applications of nanotechnology has resulted in rapid developments in fields of energy, electronics and medicine, especially for fast development of thin film solar cells and ultrasensitive sensor technology. However, development of nanoscience and technology depends on innovation of new nanomaterials with excellent physical and chemical properties. At present, the investigation has mainly focused on the binary nanomaterials such as ZnO, TiO2 and CdS because fabrication of ternary semiconducting nanomaterials is more difficult than binary semiconducting nanomaterials, especially for preparation of ternary metal sulfide alloys due to oxidation at high temperature, although the band structures of ternary semiconducting nanomaterials are more adjustable than that of binary semiconducting nanomaterials, which results in significant advantage for applications in opto-electronic devices. Consequently, there is lack of detailed information of fabrication, characterization and property ternary semiconducting nanomaterials.Aiming at synthesis of Cu-Bi-S ternary nanostructures at low temperature, this dissertation developed a simple thermal solvent route for preparation of CuBiS2 nanowires and Cu3BiS3 flower-like nanostructure using ethanol-glycerol solution mixture at temperature below 200℃. Effect of the synthesis conditions on morphology of the products has been explored and growth mechanism has been discussed in detail. The microstructural characterization reveled that multi-periodicities along the [001] direction as confirmed by electron diffraction and high resolution TEM lattice fringes happened in CuBiS2 nanowires as a result of disordering of the metal cations perpendicular to the (001) lattice plane. This structural phenomenon which is phase transition from disorder to order can be possibly used for adjust of the property of CuBiS2 nanowires. Such novel phase transiton rarely reported in the literature.The band gap of Cu3BiS3 nano-flowers and CuBiS2 nanowires were 1.17ev and 1.43eV by UV-VIS-NIR. Therefore, Cu3BiS3 nano-flowers and CuBiS2 nanowires have considerable potential applications in electron converter components and solar cell photovoltaic technology.The pore size and pore-size distribution in the Cu3BiS3 flower-like nanostructure detected by N2 gas adsorption-desorption isotherm suggest this resultant nanostructure is a good mesoporous materials which have potential applications in adsorption and optics.