Papers by Author: Soon Wook Jeong

Abstract: Capture and reforming fume gases from atmosphere became an ultimate task recently. Photocatalytic reduction to useful compounds is a key to the future. Photoinduced reduction of carbon dioxide and ammonia aqueous solution into amine compounds at room temperature and atmospheric pressure using transition metal doped titanium dioxide is reported in this paper. UV-visible spectra showed a high absorbance at 200 nm wavelength which is a characteristic of urea. High Performance Liquid Chromatography revealed presence of amine compounds and urea was found a main product of photocatalytic reaction.

Abstract: The main aim of this research was to investigate the influence of processing parameters on the me-chanical properties and morphology of porous STS:TiH₂ composites made by using spark plasma sintering method. Mechanical parameters and structural analysis of the fabricated composite have been investigated by Rockwell hardness, density tester, optical microscope, XRD and FE-SEM. In particular the porous stainless steel (STS) and titanium hydride TiH₂ composites materials with op-timal ratio were prepared with using additional hollow glass microsphere and water glass for con-trolling of the porosity degree. It is found, that the porosity degree depended on addition of TiH₂ and hollow glass additive, resulting to modification of the pore shape and size. I was shown that the dispersion of STS/TiH2 composite which sintered by spark plasma sintering method without pressure result to increasing of mechanical properties (hardness and density). According to obtained results, the addition of TiH2 powder into STS improves the mechanical property of the synthesized specimens especially the specimens with addition 20 wt% and 50 wt% of TiH₂ demonstrated high hardness values and good density.

Abstract: Titanium silicon carbide (Ti₃SiC₂) is a remarkable material for its combination of the best properties of metals and ceramics. The high purity Ti₃SiC₂ ceramic has been prepared by infiltration sintering (IS), and the effect of a small amount of Si on Ti₃SiC₂ ceramic formation was investigated. The results show that the purity of Ti₃SiC₂ ceramic could be increased significantly and the sintering time for Ti₃SiC₂ could be decreased remarkably when proper amount of Si was added in the starting mixture. The Ti₃SiC₂ sintered compact with a purity of 99.2wt% and a relative density of 97% was obtained by the infiltration sintering from a starting mixture composed of n(Ti):n(Si):n(TiC) = 1:0.3:2 at 1500 °C with holding time of 2/3h.

Abstract: We made the ZnO nanorods using wet chemical method. it is so simple, economic and suitable for large-scale production, the quality of the arrayed ZnO nanorods fabricated using these methods are not as good as that of nanorods prepared via VLD, CVDand ED method. We demonstrate that the concentration of precursors have influence on the morphology and optical properties, growth density and its distribution of the arrayed ZnO nanorods can be effectively controlled by using suitable conditions. We tried to study suitable ZnO nanorods growth condition to apply to a organic-inorganic hybrid solar cell, and we made the solar cell and investigated the energy conversion efficiency etc.

Abstract: Electrical, optical, and structural properties of amorphous indium zinc oxide (IZO) anode films grown on flexible polycarbonate (PC) substrate were investigated. The x-ray diffraction (XRD) result shows that the IZO film grown at room temperature is complete amorphous structure due to low substrate temperature. A sheet resistance of 34.1 ,/
, average transmittance above 88.9% in visible range, and root mean spare roughness of 3.5~10.5 Å were obtained even in the amorphous IZO anode film grown on PC substrate at room temperature. It is shown that the Ir(ppy)3 doped-flexible organic light emitting diode (OLED) fabricated on the amorphous IZO anode exhibit comparable current-voltage-luminance characteristics as well as external quantum efficiency and power efficiency to OLED fabricated on conventional ITO/glass substrate. These findings indicate that the IZO anode film is a promising anode material for the fabrication of flexible OLEDs.