Structural And Optical Properties Of Tin Sulfide?SnS/SnS₂? Functional Nanostructures

Metal chalcogenide semiconducting nanoparticles especially post-transition metal sulfides have been comprehensively investigated,primarily owing to their promise use in the areas of nonlinear optics,electronics,luminescence,catalysis,energy storage and conversion,Tin sulfides,which have several binary compounds such as SnS,Sn2S3,Sn3S4,Sn45;and SrnS2,have attracted significant interest because of their structural diversities.Of these compounds,tin monosulfide?SnS?and tin disulfides?SnS2?are the most important ones and have attracted much attention for their interesting properties and potential applications.The main attainments of this dissertation are not only to well synthesize the composite novel tin chalcogenides 1D,2D,and 3D nanoarchitectures?such as rods,flowers,sheets,cross type,petal-like and so on?via hydrothermal technique but also to explore their structural,optical,electrochemical and absorption/desorption properties.The morphology,composition and structure of novel tin sulfide?SnS/SnS2?based materials have been characterized by combining multiple techniques,including the field emission scanning electron microscopy?FESEM?with energy dispersive X-ray spectroscopy?EDX?,transmission electron microscopy?TEM?,high resolution transmission electron microscopy?HRTEM?with selected area electron diffraction?SAED?,X-ray diffraction?XRD?,x-ray photoelectron spectroscopy?XPS?and Raman spectroscopy?RS?.At the starting of research,the single crystalline self-assembled stannic sulfide?SnS?nanorods have been synthesized with template-free hydrothermal growth method.FE-SEM images demonstrate the high yield of 1D rod-like nanostructure of SnS.HRTEM image of single SnS nanorod reveals that the width of the nanorod is about 400 nm and the length is in several micrometers range.X-ray diffraction?XRD?and selected area electron diffraction?SAED?patterns have revealed that the as-synthesized SnS nanorods endure in single-crystallite nature.Three Raman modes,Ag= 190cm-1,B2g=160.2cm-1,B3u=213.6cm-1 were observed by Raman spectroscopy.Furthermore,hydrogen absorption characteristics of SnS nanorods performed at 373K shows good absorption capacity of 0.82 wt%.Afterward,the novel Tin sulfide?SnS?nanorods have been synthesized with the combination of SnCl₂ and Na₂S solutions.Stoichiometric ratio of 1:4 of SnCl₂·2H₂O and Na₂S.9H₂O solutions were used as main ingredients.The hydrothermal method was used for the preparation of single-crystalline stannic sulfide?SnS?nanorods having a diameter of 413 nm and length up to 2.37 micrometer.The resultant nanorods were characterized using XRD,FESEM,PL and Raman spectroscopy techniques.Elemental composition was measured through EDS.Three modes 83.3,163.1 and 220 cm-1 were perceived by Raman spectroscopy,which were comprised with nano orthorhombic SnS herzenbergite phase.Furthermore,the PL spectra illustrate a strong emission peak at 478nm representing its capability for LEDs appliances.Novel self-assembled and highly hierarchical SnS2 nano-flowers with acute edge petals have been successfully synthesized with template-free hydrothermal technique by using SnC14.5H₂O,Na₂S.9H₂O and thioglycolic acid as a precursor.FE-SEM results show that the flower-like SnS2 architecture is in the range of 4-7 micrometers.The average crystalline size of the hexagonal phase tin disulfide nano-particles is calculated to be about 22 nm from the FWHM of XRD.Furthermore,one Raman modes at Aig= 314 cm-1 has further testified the existence of the nano-hexagonal SnS2 berndtite structure.The electrochemical properties and application of cathode material for lithium-sulfur battery have been evaluated by Galvanostatic discharge/charge testing and cycling performance.These results suggest that synthesized SnS2 nano-flowers will be a promising cathode material for lithium-sulfur batteries...