Controlled Synthesis Of Semiconductor Nanomaterials And Their Optoelectronic Applications

Environmental pollution and energy crisis is a worldwide difficult problem faced by human being now.However, the research of semiconductor photocatalyst provides a new idea for solving the problem. Metal oxide is a kind of semiconductor material with excellent physical and chemical properties.They have rich morphology,structure,variable valence and adjustable oxygen vacancy concentration. And so, materials with novel structure and unique properties will have important applications in the field of optics, optoelectronics, sensors, photocatalysis and dye-sensitized solar cells.This paper aims to explore the controllable synthesis of semiconductor nano materials and increase the photocatalytic performance.1.We successfully prepared a new type of Bi2S3/BiOCl nano heterojunction structure through a simple ion exchange method.The new structure was doped with sulfur element on the BiOCl nanosheets with high activity {001} crystal surface can further expand the scope of the catalyst material in the visible light region response and enhanced photocatalytic activity under visible light catalyst material.Bi2S3/BiOCl heterojunction structure has a optimum topology structure which in favor of the charge transfer between interfaces.In addition, our research group will also extend to the BiOBr catalyst materials and successful prepare Bi2S3/BiOBr nano heterostructures.The degradation rate of Rhodamine B with the composite material is greatly improved under the visible light.The change of catalytic activity of the catalyst by ion exchange method is simple and the successful attempt would provide a new solution to prepare and modify for other semiconductor materials.2.We have successfully preparaed a square shape, uniform dispersion of BiOClxBr1-x ultrathin nanosheets whose thickness is only about 6 nm in a short period of time through regulating the proportion of halogen elements in the composite material.We are also characterization the catalyst material for its composition,morphology and structure by the XRD, TEM, EDS and AFM.We not only use the synthesis method of microwave radiation in innovation, improve efficiency and save time, also once again proved the important role of active surface of ultrathin nanosheets fully exposed in the vacancy complex on its photocatalytic activity and experimental study of halogen elements in response to competition affecting the photocatalytic activity of different wavelengths of light on the photocatalytic materials.Though under the synergistic effect of visible light sensitization pathway, indirect UV direct semiconductor excitation and competitive way of the elements,BiOClxBr1-x ultrathin nanosheets showed excellent photocatalytic properties at low load conditions.All in all, Our results would have a positive effect on the preparation of nano materials, the two-dimensional nano photocatalytic engineering materials and the development of the global environmental protection.3.We have successfully preparaed the Au-TiO2 composite nanoparticles in one step using TiCl3 and HAuCl4 in situ redox.The product size of about 100 nm, uniform for size and dispersion and has been characterized for its structure and elements distribution through EDS, XRD and so on.The experiments of degradation of RhB use the product have proved the higher photocatalytic activity than TiO2 and explain the reaction mechanism of catalytic activity of Au afterhigh loaded.Our group consider it would has a broad application prospects in photovoltaic, solar energy because its simple preparation method,mild conditions and the catalyticspecial appearance of Au-TiO2 composite nanospheres.