Controlled Synthesis Of Hierarchical Nanostructures In₂O₃ And Optical Properties

As a functional material, In2O3 is attracted much attention with its superior optical, optoelectronics and gas sensoring properties. This paper uses hydrothermal method and liquid-Solid state method to synthesis the precursor In₂S₃, then transform the In₂S₃ into the importance of semiconductor materials In2O3 by sintering in air. The present thesis is aimed at controlling the product phase, morphology, the size and doing some research for the optical properties of In2O3. Furthermore, many modern techniques including X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Field emission scanning electron microscope (FE-SEM), Energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (Raman), UV absorption spectra (UV-vis), Photoluminescence spectra (PL) were used to characterize the structure, composition, morphology, size and the optical properties of as-synthesized products. The main elements have been completed are summarized as follows:1. In the acidic solution (6.25 vol.% HAc aqueous solution), taking InCl3?4H2O and C2H5NS as raw materials, the sea urchin-like precursor In₂S₃ were obtained by low-temperature hydrothermal synthesis at 80-90℃(diameter of microspheres were 1.8-3.7μm, nano-flake thickness were 15-30nm); second, using self-made sea urchin-like microspheres In₂S₃ as precursor sintering at 600℃for 5 hours in air, finally the cubic phase sea urchin-like In2O3 microspheres were obtained (diameter of microspheres were 3-4.6μm, thickness of nano-flakes were 20-30nm, nano-particle size were 20-40nm). The structure, composition, morphology, size and the optical properties of the obtained products were characterized by X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (Raman), Field emission scanning electron microscope (FE-SEM), UV absorption spectra (UV-vis) and Photoluminescence spectra (PL) .2. In the acidic solution (6.25 vol.% HAc aqueous solution), taking InCl3·4H2O and Na2S2O3·5H2O as raw materials, the In₂S₃ microspheres were obtained by hydrothermal synthesis at 150-180℃(diameter of microspheres were 1-2.5μm); then,using self-made In₂S₃ microspheres as precursor sintering at 600℃for 5 hours in air; finally the cubic phase sea urchin-like In2O3 microspheres were obtained (diameter of microspheres were 1-2.5μm, size of nano-particles were 20-30nm). The structure, composition, morphology, size and the optical properties of the obtained products were characterized by X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (Raman), Field emission scanning electron microscope (FE-SEM), UV absorption spectra (UV-vis) and Photoluminescence spectra (PL).3. Two routes were proposed for the synthesis different morphology of In2O3 powders by using the indium chloride and thiourea as raw materials. (1) two-step synthesis:â‘ put the InCl3?4H2O and NH2CSNH2 fully mixed by carnelian mortar, then the In₂S₃ micro-cluster were obtained by sintering at 200-250℃for 0-5 hours in air;â‘¡using self-made In₂S₃ micro-cluster as precursor sintering at 600℃for 6 hours in air, finally the cubic phase hierarchical In2O3 were obtained(nano-flake thickness were 20-50nm, nano-particle size were 20-60nm); (2) one-step synthesis: put the InCl3·4H2O and NH2CSNH2 fully mixed by carnelian mortar, then transferred the mixture to corundum crucible with a cover, put the crucible containing the reactants in a Muffle furnace sintering at 600℃for 6 hours in air, after cooling naturally, the submicron polyhedral and pyramid-shaped In2O3 were obtained. The structure, composition, morphology, size and the optical properties were characterized by X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (Raman), Field emission scanning electron microscope (FE-SEM), UV absorption spectra (UV-vis) and Photoluminescence spectra (PL).