Synthesis,Characterization And Optical Properties Of ZnS Nanoparticles

Semiconductor nanomaterials have attracted much attention due to their outstanding optical,electrical properties since the 1980s.Semiconductor nanomaterials,especially the cadmium sulfide,zinc sulfide,as the most classic nanometer material system attracted a lot of attention for its unique optical property,piezoelectric properties and excellent magnetic,thermal performance.It is of great significance to explore the controllable preparation of semiconductor nanomaterials,study the influence of preparation conditions on the structures of semiconductor nanomaterials and elucidate the relationship between semiconductor nanostructures and their properties for the development of material science.In this thesis,zinc sulfide with different morphologies and structures were successfully prepared via a hydrothermal synthesis method.Their optical properties were further studied.The main research contents in this thesis are described as follows:1.The monodisperse Wurtzite-type ZnS microspheres were synthesized by hydrothermal method at relatively low reaction temperature(160?),using GSH as a sulfur source,ZnCl2 as a Zinc source,CTAB as the surfactant and ethylenediamine(en)as reaction medium.The diameter of ZnS microspheres changed from 500 nm to 1?m.Through controlling the concentrations of CTAB and ethylenediamine in solution,ZnS hollow spheres with different structures have been successfully synthesized.The luminescence properties of these ZnS hollow spheres were measured.It was found tha when the concentration of ethylenediamine was 5 ml,the hollow spheres shows the best fluorescence characteristics.In this thesis,by means of concentrations of the CTAB and ethylenediamine in reaction solution,six kinds of wurtzite ZnS hollow microspheres.were successfully fabricated.After the synthesis condition optimization,the ZnS hollow nonospheres with the highest fluorescence properties were fabricated.The morphologies of microspheres.were observed by SEM and their phase structures were analyzed by X-ray diffraction.In addition,the optical properties for the samples synthesized at different conditions were characterized by spectrophotometer.The experimental results show that CTAB can promote the formation of the hollow spheres.The ZnS hollow microspheres with different thickness of shell can be obtained by changing the reaction parameters.PL test results show that the fluorescence intensity of hollow microsphere is higher than that of solid microsphere.2.The monodisperse Wurtzite-type ZnS microspheres were synthesized by hydrothermal method at relatively low reaction temperature(150?),using zinc acetate,thiourea,gadolinium nitrate as reactants,polyvinyl pyrrolidone as the surfactant.The morphologies of microspheres were observed by SEM and their phase structures were analyzed by X-ray diffraction.The optical properties for the Gd doped ZnS nanospheres were characterized by spectrophotometer.The results show that the doping of Gd will not obviously change the morphology and crystal structure of ZnS.When the concentration of the Gd doping is 2%,the fluorescence intensity reaches the maximum.