Analysis And Preparation Of Different Morphologies And Properties Of Nanomaterials Doped ZnS

As an important type of Ⅱ-Ⅵ compound semiconductor material, ZnS has excellent optical and electrical properties, which has been widely used in the electronic device, luminescent device, solar cell and chemical industry. In this dissertation, the ZnS:Cu particles and Zn1-xCdxS nanoparticles were prepared by using hydrothermal method, and their physical and chemical properties were characterized and analyzed. The discussions are presented as following.The flower-like ZnS:Cu nanostructures were synthesized via hydrothermal method. And X-ray diffraction (XRD), Field-emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM) and Luminescence spectrometer are used to characterize the phase, morphology and photoluminescence (PL) properties of the ZnS:Cu nanoparticles prepared under different contents of tetraethyl orthosilicate (TEOS). The results show that all samples have sphalerite structures. Because of the effect of TEOS, the obtained flower-like microspheres are composed of nanosheets with average thicknesses of30nm. And with the increase of content of TEOS (Omol/L-1.35mol/L), the intensity of PL spectra fisrstly increases, then decreases, but the PL emission peak located at560nm keeps constant for the different contents of TEOS, which is attributed to the transition from sulfur vacancies to t2states of Cu.Zn1-xCdxS (O≤x≤1) alloy nanoparticles have been prepared via hydrothermal approach. The effect of content of Cd on the structure, size, photoluminescence spectra and UV-vis diffuse reflectance spectroscopy was investigated. With increasing the percentage of Cd in the ternary compound Zn1-xCdxS, the lattice structure gradually changes from cubic to hexagonal, and the lattice parameters (a,c) calculated from XRD patterns increase linearly with x, and the nanoparticle’s size becomes larger from20nm to40nm. Furthermore, it shows that the prepared samples have two emission bands which have a remarkable red-shift, and a small red-shift of UV-vis absorption peak can also be found, which implies that the band gap of samples can be tuned by changing the contents of Cd. All the results provide clear evidence for the formation of the alloyed Zn1-xCdxS nanocrystals, and their size and optical properties can be continuously modulated by tuning compositions of Zn1-xCdxS. In addition, from the results of the photocatalysis experiment the conversion of MO degradation using Zno.6Cdo.4S as the photocatalyst is up to97.5%after three hours under visible light irradiation.