The Synthesis Of CdTe Semiconductor Nanomaterials And Its Applications

The size-depengent properties of CdTe nanostructure materials make it an ideal material for wide range of application in the fields of light-emitting devices, bioimaging, photovoltaics, biological sensors and chemical sensors. CdTe nanomaterials have drawn great attention on both fundamental research and potential applications. Although there have been a lot of reports about the theory, the synthesis technology and their application, it is still necessary and important to pay more attention to both synthesis and application of CdTe semiconductor nanomaterials for the complete development of this subject. In this thesis, a novel method has been developed for the synthesis of CdTe quantum dots-polystyrene fluorescent composite nanospheres by a two-step route; the interactions between CdTe nanowires and CdTe QDs have been studied; fabrication and characterization of Ag-doped CdTe nanowires also have been reported. The main concents and results are listed as follows:1. CdTe quantum dots-polystyrene (CdTe/PS) composite microspheres were synthesized by a two-step route. The products were characterized by X-ray powder diffraction, high-resolution transmission electron microscopy, fluorescent microscope imaging and fluorescence spectrometer. It was shown that the composite microspheres were spherical and relatively uniform with a diameter of 120 nm. Compared with other methods, the present method was simple, efficient and inexpensive. Furthermore, the composite microspheres exhibited favorable water-dispersible, stable, size-tunable and fluorescent properties. At last, the possible formation mechanism of the composite microspheres was investigated.2. The interactions between CdTe QDs and CdTe nanowires have been studied by spectroscopic techniques. The results showed that the fluorescence of CdTe QDs was strongly quenched by CdTe nanowires, which was proved to be a static quenching procedure according to the stern-volmer equation. The possible mechanism of the interaction was proposed according to the results of thermodynamic parameters, it was also found that electrostatic interaction played a key role in the binding process, which provide a theoretical basis for formation mechanism of CdTe nanowires.3. Fabrication of Ag doped CdTe nanowires by impregnation method. The as-prepared composite nanowires were characterized by high-resolution transmission electron microscopy, X-ray powder diffraction, thermo gravimetric analyzer and ultraviolet-visible absorption spectra. The thermal characteristics of the Ag doped CdTe nanowires has also been studied. The results showed that the morphology of the nanowire changed a lot, and the thermal stability of the nanowires has been improved.