• Title/Summary/Keyword: Sol-gel dip coating

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A Study on the Electrical Properties of Thin Film Type Humidity Sensor (박막형 습도센서의 전기적 특성에 대한 연구)

  • You, Do-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.6
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    • pp.1012-1016
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    • 2008
  • [ $TiO_2-V_2O_5$ ] sol was fabricated using sol-gel method and $TiO_2-V_2O_5$ thin films were fabricated using dip-coating method. $V_2O_5$ sol was added 0.01mole, 0.03mole, 0.05mole into $TiO_2$ sol. As a results of crystalline properties, $V_2O_5$ peaks were not found in spite of $V_2O_5$ additive. Thickness of thin films increased $0.1{\sim}0.25{\mu}m$ every a dipping. Capacitance of thin films increased with increasing heat treatment temperature and it increased largest at $700^{\circ}C$. Capacitance of thin films decreased with increasing $V_2O_5$ additive and it increased largest at 0.01mole. Because adsorption time and desorption time of thin films was about 2 minutes 40 seconds and about 3 minutes 40 seconds respectively, adsorption time was faster about 1 minutes than desorption time.

Efficiency Improvement of Metal-Mesh Electrode Type Photoelectrochemical Cells by Oxides Layer Coatings (산화물박막 증착에 의한 금속 메쉬전극 구조 광전기화학셀의 효율 개선에 관한 연구)

  • Han, Chi-Hwan;Park, Seon-Hee;Sung, Youl-Moon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.3
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    • pp.584-587
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    • 2011
  • In this work, the $TiO_2$ and $SnO_2$ thin films as blocking layers were coated directly onto the metal-mesh electrode surface to prevent unnecessary inflow of back-transfer electrons from the electrolyte ($I^-/I_3^-$) to the metal-mesh electrode. The DSCs were fabricated with working electrode of SUS mesh coated with blocking $TiO_2$ and $SnO_2$ layers, dye-attached mesoporous $TiO_2$ film, gel electrolyte and counter electrode of Pt-deposited F:$SnO_2$. From the experimental result, it was ascertained that the efficiency of metal electrode coated with $TiO_2$ by Dip-coating was superior to that of metal electrode coated with $SnO_2$ by Dip-coating and screen printing with the results of experiments. The photo-current conversion efficiency of the cell obtained from optimum fabrication condition was 3% ($V_{oc}$=0.61V, $J_{sc}$=11.64 mA/$cm^2$, ff=0.64) under AM1.5, 100 mW/$cm^2$ illumination.

Humidity Sensitive Properties of $V_2O_5$-added $TiO_2$ Ceramics ($V_2O_5$ 첨가에 따른 $TiO_2$ 세라믹스의 감습특성)

  • Hyun, You-Do
    • Proceedings of the KIEE Conference
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    • 2008.05a
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    • pp.161-163
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    • 2008
  • $TiO_2-V_2O_5$ sol was fabricated using sol-gel method and $TiO_2-V_2O_5$, thin films were fabricated using dip-coating method. $V_2O_5$ sol was added 0.01mole, 0.03mole, 0.05mole into $TiO_2$ sol. Capacitance of thin films decreased with increasing $V_2O_5$ additive and it increased largest at 0.01mole. Because adsorption time and desorption time of thin films was about 2 minutes 40 seconds and about 3 minutes 40 seconds respectively, adsorption time was faster about 1 minutes than desorption time.

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Development of $YSZ/La_0.85S_r0.15MnO_3$ Composite Electrodes for Solid Oxide Fuel Cells (고체산화물 연료전지용 $YSZ/La_0.85S_r0.15MnO_3$계 복합전극의 개발)

  • 윤성필;현상훈;김승구;남석우;홍성안
    • Journal of the Korean Ceramic Society
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    • v.36 no.9
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    • pp.982-990
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    • 1999
  • YSZ/LSM composite cathode was fabricated by dip-coating of YSZ sol on the internal pore surface of a LSM cathode followed by sintering at low temperature (800-100$0^{\circ}C$) The YSZ coating significantly increased the TPB(Triple Phase Boundary) where the gas the electrode and the electrolyte were in contact with each other. Sinter the formation of resistive materials such as La2Zr2O7 or SrZrO3 was prevented due to the low processing temperature and TPB was increased due to the YSZ film coating the electrode resistance (Rel) was reduced about 100 times compared to non-modified cathode. From the analysis of a.c impedance it was shown that microstructural change of the cathode caused by YSZ film coating affected the oxygen reduction reaction. In the case of non-modified cathode the RDS (rate determining step) was electrode reactions rather than mass transfer or the oxygen gas diffusion in the experimental conditions employed in this study ($600^{\circ}C$-100$0^{\circ}C$ and 0,01-1 atm of Po2) for the YSZ film coated cathode however the RDS involved the oxygen diffusion through micropores of YSZ film at high temperature of 950-100$0^{\circ}C$ and low oxygen partial pressure of 0.01-0.03 atm.

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A pH Optosensor Based on Fluoresence from Nile Blue Encapsulated within Silica Sol-Gel Film (실리카 졸-겔막을 이용한 pH 광학센서)

  • Lee, Jung-Min;Li, Ming;Lee, Sang-Hak;Kim, Young-Sun;Kim, Chang-Jin;Lee, Boo-Huyng
    • Journal of Sensor Science and Technology
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    • v.13 no.3
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    • pp.169-174
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    • 2004
  • A fiber optic pH sensor has been fabricated using nile blue entrapped in an ammonia catalyzed silica sol-gel film coated on glass substrate by dip-coating. The sensor was fixed on the end of an optical fiber. The sensor showed pH sensitivity when dipped into liquids at different pHs. Linear and reproducible responses were obtained in standard buffer solutions in the pH range $6.0{\sim}8.5$, which encompasses the clinically-relevant range. The effects of interferences on the determination of pH were also investigated. The sensors were successfully applied to the determination of pH in different commercial ionic drinks.

Preparation and Properties of Y2O3-Doped ZrO2 Films on Etched Al Foil by Sol-Gel Process

  • Chen, Fei;Park, Sang-Shik
    • Korean Journal of Materials Research
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    • v.25 no.2
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    • pp.107-112
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    • 2015
  • The oxide films formed on etched aluminum foils play an important role as dielectric layers in aluminum electrolytic capacitors. $Y_2O_3$-doped $ZrO_2$ (YZ) films were coated on the etched aluminum foils by sol-gel dip coating, and the electrical properties of YZ-coated Al foils were characterized. YZ films annealed at $450^{\circ}C$ were crystallized into a cubic phase, and as the $Y_2O_3$ doping content increased, the unit cell of $ZrO_2$ expanded and the grain size decreased. The etch pits of Al foils were filled by YZ sol when it dried at atmospheric pressure after repeating for several times, but this step could essentially be avoided when being dried in a vacuum. YZ-coated foils indicated that the specific capacitance and dissipation factor were $2-2.5{\mu}F/cm^2$ and 2-4 at 1 kHz, respectively, and the leakage current and withstanding voltage of films approximately 200 nm thick were $5{\times}10^{-4}A$ at 21 V and 22 V, respectively. After being anodized at 500 V, the foils exhibited a specific capacitance and dissipation factor of $0.6-0.7{\mu}F/cm^2$ and 0.1-0.2, respectively, at 1 kHz, while the leakage current and withstanding voltage were $2{\times}10^{-4}-3{\times}10^{-5}A$ at 400 V and 420-450 V, respectively. This suggests that YZ film is a promising dielectric that can be used in high voltage Al electrolytic capacitors.

Preparation of Thin Film Electrolyte for Solid Oxide Fuel Cell by Sol-Gel Method and Its Gas Permeability (졸-겔법을 이용한 고체산화물연료전지의 전해질 박막 제조 및 가스 투과도)

  • Son, Hui-Jeong;Lee, Hye-Jong;Lim, Tak-Hyoung;Song, Rak-Hyun;Peck, Dong-Hyun;Shin, Dong-Ryul;Hyun, Sang-Hoon;Kilner, John
    • Journal of the Korean Ceramic Society
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    • v.42 no.12 s.283
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    • pp.827-832
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    • 2005
  • In this study, thin electrolyte layer was prepared by 8YSZ ($8mol\%$ Yttria-Stabilized Zirconia) slurry dip and sol coating onto the porous anode support in order to reduce ohmic resistance. 8YSZ polymeric sol was prepared from inorganic salt of nitrate and XRF results of xerogel powder exhibited similar results $(99.2\pm1wt\%)$ compared with standard sample (TZ-8YS, Tosoh Co.). The dense and thin YSZ film with $1{\mu}m$ thickness was synthesized by coating of 0.7M YSZ sol followed by heat-treatment at $600^{\circ}C$ for 1 h. Thin film electrolyte sintered at $1400^{\circ}C$ showed no gas leakage at the differential pressure condition of 3 atm.

Synthesis of Li4Ti5O12 Thin Film with Inverse Hemispheric Structure

  • Lee, Sung-Je;Jung, Kwang-Hee;Park, Bo-Gun;Kim, Ho-Gi;Park, Yong-Joon
    • Bulletin of the Korean Chemical Society
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    • v.31 no.2
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    • pp.360-364
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    • 2010
  • $Li_4Ti_5O_{12}$ thin film with inverse hemispheric structure was fabricated on a Pt/Ti/$SiO_2$/Si substrate by the sol-gel and dip coating method for use as an anode for 3-dimensional (3D) thin-film batteries. Polystyrene (PS) beads of 400 nm diameter were used to prepare the template for the inverse hemispheric structure. A coating solution prepared using precursor sources was dropped on the template-deposited substrates, which were then calcinated at $400^{\circ}C$. The template was removed by calcination, and the inverse hemispheric structure was successfully formed by an annealing process. The cyclic performance during high-rate charge/discharge processes of the $Li_4Ti_5O_{12}$ film with inverse hemispheric structure was superior to that of the flat $Li_4Ti_5O_{12}$ film.

Study on the Properties of $B_2O_3$-$SiO_2$and $Al_2O_3$-$SiO_2$Coating Films by the Sol-Gel Method (Sol-Gel법으로 제조한 $B_2O_3$-$SiO_2$$Al_2O_3$-$SiO_2$ 박막의 특성에 관한 연구)

  • 황규석;김병훈;최석진
    • Journal of the Korean Ceramic Society
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    • v.27 no.5
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    • pp.583-588
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    • 1990
  • Glass films in the binary system B2O3-SiO2 and Al2O3-SiO2 were prepared on soda-lime-silica slide glass by the dip-coating technique from TEOS and boric acid or aluminum nitrate. Thickness of the films varying with viscosity and withdrawal speed were measured and effect of composition and firing temperature on the properties such as transmittance and refractive index were investigated. nM2O3.(100-n)SiO2(M=B or Al) films containing up to 20mol% B2O3 and 40mol% Al2O3 were transparent. Maximum transmittance at visible range were obtained for the sample containing 15mol% Ba2O3 and 32.5mol% Al2O3 and heat-treated at 50$0^{\circ}C$, respectively. Refractive index of the film containing 15mol% B2O3 was mininum in the B2O3-SiO2 binary system and minimal refractive index was appeared at the film containing 32.5mol% Al2O3. In IP spectra, addition of B2O3 were increased absorption peak intensity of B-O and Si-O-B bond and addition of Al2O3 were decreased absorption peak intensity of Si-O bond, respectively.

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Bond Strength of SrZrO3 Coatings on Ag Sheathed Bi(2223) Mono-core Tape (은이 피복된 단심 Bi(2223) 초전도 선재에 대한 SrZrO3 코팅층의 접착강도 특성)

  • Lee, Se-Jong;Ye, Kyung-Hwan;Lee, Deuk-Yong;Song, Yo-Seung
    • Journal of the Korean Ceramic Society
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    • v.39 no.10
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    • pp.1001-1006
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    • 2002
  • Bond strength of $SrZrO_3$ resistive oxide barrier on Ag sheathed Bi(2223) tapes prepared by the sol-gel and dip-coating method was evaluated with an aid of Taguchi method and $L_18(2^1{\times}3^7)$ orthogonal arrays to determine the optimal process combination of levels of factors that best satisfy the bigger is better quality characteristic. The observed optimal condition is as follows: Sr/Zr mol ratio(0.3/0.7), amount of organic vehicle(5 wt%), drying temperature and time(160${\circ}C$, 10 min), heat treatment temperature and time(500${\circ}C$, 20 min), respectively. ANOVA analysis suggested that the influence of the factors within ${\alpha}$=0.1 was significant with a 90% confidence level.