• Title/Summary/Keyword: Titanium oxide films

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Fabrication and characterization of hybrid AlTiSrO/rGO thin films for liquid crystal orientation (액정 배향용 하이브리드 AlTiSrO/rGO 박막 제조 및 특성 평가)

  • Byeong-Yun Oh
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.17 no.3
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    • pp.155-165
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    • 2024
  • A hybrid thin film was prepared by doping reduced graphene oxide (rGO) into a sol-gel solution mixed with aluminum, titanium, and strontium using a brush coating method. The annealing temperature was carried out at 160, 260, and 360℃, and the difference in oxidation reaction was observed. The sol-gel solution created during the membrane manufacturing process generates a contractile force due to the shear stress of the brush bristles, forming a microgroove structure. This structure was confirmed through scanning electron microscopy analysis, and the presence of rGO was clearly revealed. As the annealing temperature increases, the oxidation and reduction reactions on the thin film surface become more active, so the intensity of the surface mixture increases. Moreover, the electro-optical properties were stabilized and improved by increasing the intensity of the mixtures. Likewise, the voltage-capacitance values are also significantly improved. Lastly, the transmittance measurement showed that it was suitable for liquid crystal display application.

Studies on the Electrochemical Properties of $TiO_{2-x}$ Thin Films ($TiO_{2-x}$ 박막의 전기화학적 성질에 관한 연구)

  • Q Won Choi;Chu Hyun Choe;Ki Hyung Chjo;Yong Kook Choi
    • Journal of the Korean Chemical Society
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    • v.30 no.1
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    • pp.19-26
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    • 1986
  • A titanium oxide thin films were prepared by air oxidation and vapour oxidation and a $TiO_2$ single crystal was reduced by heating in an argon atmosphere. All the electrode characteristics of the Ti$O_{2-x}$, thin films are not different from those of slightly reduced single crystal rutile. In cyclic voltammogram of oxygen containing electrolyte solution at Ti$O_{2-x}$ electrodes, cathodic peaks were observed at between -0.8V and -1.0V vs. SCE. The cathodic current near 0V vs. SCE in saturated solution with nitrogen was observed to be greater than in saturated solution with air. The chronoamperogram was represented by the equation of i = $i_0e^{-kt}$, when the rate constant k was represented by the equation of k =$k_0{[H^+]}^nexp(A{\eta}+E_a/RT)$ The values of activation energy $E_a $were found to be 4.6~4.8kcal/mole in overpotential range of 0.035∼0.145 V and 1.6kcal/mole in overpotential range of 0.2∼0.5V. The values of n and A were found to be 0. 1 and 5.4~5.6/V in range of 0.035~0.145V, and in range of 0.2~0.5V, to be 0.04 and 1.3/V, respectively. This can be interpreted as an totally irreversible reduction of oxygen.

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Effect of TiO2 Coating Thickness on Photovoltaic Performance of Dye-sensitized Solar Cells Prepared by Screen-printing Using TiO2 Powders

  • Lee, Deuk Yong;Cho, Hun;Kang, Daejun;Kang, Jong-Ho;Lee, Myung-Hyun;Kim, Bae-Yeon;Cho, Nam-Ihn
    • Journal of the Korean Ceramic Society
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    • v.51 no.4
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    • pp.362-366
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    • 2014
  • Dye-sensitized solar cells (DSSCs) were synthesized using a $0.25cm^2$ area of a $TiO_2$ nanoparticle layer as the electrode and platinum (Pt) as the counter electrode. The $TiO_2$ nanoparticle layers (12 to 22 ${\mu}m$) were screen-printed on fluorine-doped tin oxide glass. Glancing angle X-ray diffraction results indicated that the $TiO_2$ layer is composed of pure anatase with no traces of rutile $TiO_2$. The Pt counter electrode and the ruthenium dye anchored $TiO_2$ electrode were then assembled. The best photovoltaic performance of DSSC, which consists of a $18{\mu}m$ thick $TiO_2$ nanoparticle layer, was observed at a short circuit current density ($J_{sc}$) of $14.68mA{\cdot}cm^{-2}$, an open circuit voltage ($V_{oc}$) of 0.72V, a fill factor (FF) of 63.0%, and an energy conversion efficiency (${\eta}$) of 6.65%. It can be concluded that the electrode thickness is attributed to the energy conversion efficiency of DSSCs.

Photo-Electrochemical Properties of $TiO_2$ Electrodes Prepared by Anodic Oxidation (양극산화에 의해 제조된 $TiO_2$ 전극의 광전기화학적 성질)

  • Yong Kook Choi;Soon Ki Lee;Q Won Choi;Jeong Sub Seong;Ki Hyung Chjo
    • Journal of the Korean Chemical Society
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    • v.37 no.12
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    • pp.1010-1018
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    • 1993
  • The titanium oxide thin films were prepared by anodic oxidation. The Photo-electrochemical properties of the electrodes were studied in 1 M NaOH solution. The flat band potentials of $TiO_2$ electrodes prepared by anodic oxidation showed around -0.8V and the values were shifted 0.2V to the positive potential direction that of single crystal $TiO_2$. Reduction potential of oxygen by cyclic voltammetry showed around -0.95V vs. SCE and these reactions were processed totally irreversible. The photocurrent of electrodes were showed shorter wavelength than that of single crystal $TiO_2$ and its current density decreased.

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A Study of Photoelectrolysis of Water by Use of Titanium Oxide Films (산화티타늄 피막의 광 전기분해 특성에 관한 연구)

  • Park, Seong-Young;Cho, Byung-Won;Ju, Jeh-Beck;Yun, Kyung-Suk;Lee, Eung-Cho
    • Applied Chemistry for Engineering
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    • v.3 no.1
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    • pp.88-99
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    • 1992
  • For the development of semiconducting photoelectrode to be more stable and efficient in the process of photoelectrolysis of the water, pure titanium rods were oxidized by anodic oxidation, furance oxidation and flame oxidation and used as electrodes. The Indium islands were formed by electrodeposition of "In" thin film on $TiO_2$ and Ti by electrodeposition. Also $A1_2O_3$ and NiO islands were coated on Ti by the electron-beam evaporation technique. The maximum photoelectrochemical conversion efficiency(${\eta}$) was 0.98% for flame oxidized electrode($1200^{\circ}C$ for 2min in air). Anodically oxidized electrodes have photoelectrochemical conversion efficiency of 0.14%. Furnace oxidized electrode($800^{\circ}C$ for 10min in air) has 0.57% of photoelectrochemical efficiency and shows a band-gap energy of about 2.9eV. The $In_2O_3$ coated $TiO_2$ exhibits 0.8% of photoelectrochemical efficiency but much higher value of ${\eta}$ was obtained with the Increase of applied blas voltage. However, $Al_2O_3$ or NiO coated $TiO_2$ shows much low value of ${\eta}$. The efficiency was dependent on the presence of the metallic interstitial compound $TiO_{0+x}$(x<0.33) at the metal-semiconductor interface and the thickness of the suboxide layer and the external rutile scale.

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