Syntheses And Characterization Of SnS Nanocrystals By Hydrothermal And Solvothermal Techniques

The present thesis is focused on the syntheses and characterization of SnS nanomaterials. By the adoption of new hydrothermal/solvothermal methods,the shape-controlled syntheses of semi-conducting SnS nanocrystals have been achieved. Meanwhile, many techniques including X-ray diffraction(XRD), energy dispersive X-ray spectroscopy(EDS), transmission electron microscopy(TEM),scanning electron microscopy( SEM),high resolution transmission electron microscopy(HRTEM), and selected area electron diffraction(SAED), etc. were employed to characterize the as-synthesized products.The main work completed in this thesis can be summarized as the following:1.With the use of the surfactant of PVP, shape-controlled syntheses of flower-like SnS nanocrystals were achieved via hydrothermal reactions of SnCl2.2H2O and CS(NH2)2 in water at 200℃for 24h.The flower-like SnS nanostructures were assembled by single-crystal nanoplates and nanoblets.The morphologies of the obtained products could be controlled simply by adjusting reaction temperature and reaction time, the amount of PVP. The as-prepared SnS nanocrystals were characterized by XRD,SEM,TEM,HRTEM and SAED, etc. The possible formation mechanisms of SnS nanocrystals by the hydrothermal processing were also discussed.2.Using the surfactant of PEG, shape-controlled syntheses of regular SnS nanoplates with thickness of about 100nm were achieved via hydrothermal reactions of SnCl2.2H2O and CS(NH2)2 in water at 200℃for 24h.The morphologies of the obtained products could be controlled by adjusting reaction temperature,reaction time, and the molar ratio of reactants. The as-prepared SnS nanocrystals were characterized by XRD,SEM,TEM and EDS, etc.3.Using the surfactant of PEG, shape-controlled syntheses of hollow microspheres composed of nanoflakes with thickness of about 100nm were carried out via solvothermal reactions of SnCl2.2H2O and CS(NH2)2 in ethylene glycol at 200℃for 24h. The morphologies of the obtained products could be controlled by adjusting reaction temperature, reaction time and the amount of PEG. The as-prepared SnS hollow microspheres were characterized by XRD,SEM,TEM,HRTEM and SAED, etc. The possible formation mechanisms of the hollow microspheres SnS powders were discussed, too.The results presented here put forward to some facile routes to achieve morphology-and phase-controlled syntheses of SnS nanomaterials, which would be helpful for us to fabricate SnS-based nanodevices.