• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.6
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• pp.267-271
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• 2010

Super hydrophilic and high transparent $TiO_2$ thin films were successfully fabricated by sol-gel method without an irradiation of UV light. In addition, surfactant Tween 80 was used for increasing the transmittance of the thin films. When the contents of Tween 80 in $TiO_2$ solution were 0.0, 1.0, 3.0, 5.0 wt%, the transmittance of $TiO_2$ thin films was ca. 74.31%, 74.25%, 79.69%, 81.99% at 550 nm wavelength, respectively. The contact angles of fabricated $TiO_2$ thin films with or without Tween 80 were from ca. $4.0^{\circ}$ to $4.5^{\circ}$. The $TiO_2$ thin films annealed over $400^{\circ}C$ showed anatase crystal structure and the photocatalytic property that decomposed methyl orange with UV irradiation. The surface morphologies, optical properties and contact angle of prepared thin films with different contents of Tween 80 were evaluated by field emission scanning electron microscope (FE-SEM), X-ray diffratometer (XRD), UV-Vis spectrophotometer and contact angle meter.

• Journal of the Korean Ceramic Society
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• v.31 no.5
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• pp.499-504
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• 1994

PbTiO3 thin films were prepared by sol-gel spin coating method using metal alkoxide and diethanolamine (DEA). The precipitation of the PbTiO3 sol occurred at pH 7.3 with HNO3 addition, regardless of the amount of DEA. The gelation time of the PbTiO3 sol was reduced with increasing amount of HNO3 and/or water. When the PbTiO3 films prepared by 0.2 molar coating solution were annealed at $650^{\circ}C$ for 30 min, dense and single phase perovskite films were obtained. Dielectric constant and loss tangent of the film were 239 and 0.01 at 1 kHz, respectively.

• Journal of Ocean Engineering and Technology
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• v.17 no.3 s.52
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• pp.52-56
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• 2003

This study investigates the photoelectrochemical behavior of STS304 steel with TiO2 thin films coating, applied by sol-gel mehod, for the purpose of cathodic photoprotection of the steel corrosion. One time TiO2-coated STS304 steel, adapted with two kinds of TiO2 sol solution, has the most dominant photopotential abilities, which was -200mV vs. SCE and -500mV vs. SCE under illumination with 40 W fluorescent lamp, respectively. That had yielded more negative values than the corrosion potential of the bare metal(-130mv vs.SCE). The bleaching of TCE was confirmed on TiO2-coated STS304 steel under UV-illumination with 20W Black-light. This Study concluded that Ti02-coated STS304 exhibited both a cathodic photoprotection effect against corrosion and a photocatalytic self-cleaning effect.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.4
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• pp.173-177
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• 2010

Thermal stabilizing effect of $Yb^{3+},\;Er^{3+}$ codoping into $TiO_2$ powder prepared by sol-gel method and its upconversion characteristics were analyzed. The effect of $TiO_2:Yb^{3+},\;Er^{3+}$ ions on crystallinity and phase transition was studied by X-ray diffraction (XRD). The change of band-gap energy induced from Yb and Er codoping was analyzed by UV-Vis. The band-gap energy of $TiO_2$ have been slightly narrowed by $Yb^{3+},\;Er^{3+}$ codoping, which indicated that the $Yb^{3+},\;Er^{3+}$ ions can enhance the photo-catalytic property of $TiO_2$. green and red up-conversions of $Yb^{3+}$ and $Er^{3+}$ co-doped $Y_2O_3:Yb^{3+},\;Er^{3+}$ phosphor were analyzed by PL equipped with 980 nm laser.

• Korean Journal of Materials Research
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• v.28 no.11
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• pp.620-626
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• 2018

Highly self-cleaning thin films of $TiO_2-SiO_2$ co-doped with Ag and F are prepared by the sol-gel method. The asprepared thin films consist of bottom $SiO_2$ and top $TiO_2$ layers which are modified by doping with F, Ag and F-Ag elements. XRD analysis confirms that the prepared thin film is a crystalline anatase phase. UV-vis spectra show that the light absorption of $Ag-F-TiO_2/SiO_2$ thin films is tuned in the visible region. The self-cleaning properties of the prepared films are evaluated by a water contact angle measurement under UV light irradiation. The photocatalytic performances of the thin films are studied using methylene blue dye under both UV and visible light irradiation. The $Ag-F-TiO_2/SiO_2$ thin films exhibit higher photocatalytic activity under both UV and visible light compared with other samples of pure $TiO_2$, Ag-doped $TiO_2$, and F-doped $TiO_2$ films.

• Journal of Hydrogen and New Energy
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• v.13 no.3
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• pp.224-232
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• 2002

CdS-$TiO_2$ nano-composite sol was prepared by the sol-gel method in organic solvents at room temperature and further hydrothermal treatment at various temperatures to control the physical properties of the primary particles. Again, CdS-$TiO_2$ composite particulate films were made by casting CdS-$TiO_2$ sols onto $F:SnO_2$ conducting glass and then heat-treatment at $400^{\circ}C$. Physical properties of these 61ms were further controlled by the surface treatment with $TiCl_4$, aqueous solution. The photo currents and hydrogen production rates measured under the experimental conditions varied according to the $CdS/[CdS+TiO_2]$ mole ratio and the mixed-sol preparation method. For $CdS-TiO_2$ composite sols prepared in IPA, CdS particles were homogeneously surrounded by $TiO_2$ particles. Also, the surface treatment with $TiCl_4$ aqueous solution caused a considerable improvement in the photocatalytic activity, probably as a result of close contacts between the primary particles by the etching effect of $TiCl_4$. It was found that the photoelectrochemical performance of these particulate films could be effectively enhanced by this approach.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.56.2-56.2
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• 2011

고효율 염료감응 태양전지를 제작하기 위해 Sol-gel법을 사용하여 $TiO_2$ 분말을 제조하였다. 제조 과정 중 다양한 양의 nitric acid를 첨가하여 pH를 조절하였다. Sol-gel법을 위한 출발 물질로 titanium (IV) isopropoxide(TTIP)와 DI water를 사용하였으며 nitric acid은 0, 0.05, 0.1, 0.15의 몰비(nitric acid/TTIP)로 첨가하였다. 첨가한 결과 pH는 $22^{\circ}C$에서 각각 5.52, 2.26, 1.68, 1.38이었다. 얻어진 $TiO_2$ 콜로이드 용액은 결정성 있는 분말로 제조 후 $5{\times}5[mm^2]$ 크기의 염료감응 태양전지를 제작하는데 사용 되였다. $TiO_2$의 결정구조 및 형태는 cell의 XRD와 FE-SEM으로 분석되었고 전기화학적 특성을 분석하기 위해 irradiation of AM 1.5 ($100mW/cm^2$) simulatedsunlight에서 I-V 곡선을 측정하였다. 측정 결과 몰비(nitric acid/TTIP) 0.05, pH가 2.26일 때 가장 우수한 효율 특성을 보였다.

• Bulletin of the Korean Chemical Society
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• v.28 no.9
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• pp.1463-1466
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• 2007

Single phases of multi-component oxides films, ZrTiO4 and Ta2Zr6O17, could be synthesized by using the combinatorial approach through surface sol-gel route, coating the appropriate mole ratio of 100 mM zirconium butoxide, tantalum butoxide and titanium butoxide precursors on Pt/Ti/SiO2/Si (100) substrate, following pyrolysis at 450 oC, and annealing them at 770 oC. Both the films and bulks of ZrTiO4 and Ta2Zr6O17 showed very stable dielectric properties in temperature range, ?140 to 60 oC, and frequency range, 100 Hz to 1 MHz, promising their applications in wide range of temperatures and frequencies. The dielectric constants of the films were lower and a little more dependent on frequency than those of the bulks. The reduction of dielectric property in the film was mainly due to the interfacial effects that worked as series and parallel-connected capacitances toward the substantial film capacitance.

• Journal of the Korean Ceramic Society
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• v.38 no.7
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• pp.660-666
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• 2001

수용계를 이용하여 졸겔법으로 중성 TiO$_2$졸을 제조하였다. 용매로 에탄올을 사용한 경우 메탄올에 비해 졸의 안정성이 우수하였다. 졸 제조시 에탄올을 사용하면, 메탄올을 용매로 사용할 경우보다 중심 금속에 부착되는 알콕시족의 크기가 작아져서 티타늄알콕사이드의 가수분해 속도가 빨라지기 때문이다. TTIP : AcAc : EtOH : $H_2O$ : PEG : HCl의 몰비가 1 : 1 : 8 : 50 : 0.5 : 0.15의 조성을 갖는 에탄올 용매 졸은 30일까지도 안정한 상태를 유지하였고 코팅성이 양호하였다. 10회 반복 침지, 건조 및 50$0^{\circ}C$에서 열처리된 두께 약 $1.5mu extrm{m}$의 TiO$_2$박막은 표면이 균질하고 치밀한 미세구조를 보였다. 제조한 TiO$_2$박막은 가시광선 영역에서 약 70%의 투과도를 나타내었다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.6
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• pp.418-424
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• 2000

Pure $TiO_2$and 10 mol % Pb-doped $TiO_2(Pb_xTi_{1-x}O_2$(x = 0.1)) powder and thin films have been prepared by the sol-gel method. Titanium isopropoxide and ethanol are used for pure $TiO_2$, lead acetate trihydrate and titanium triisopropoxide monoacethylacetonate are used for Pb-doped $TiO_2$, respectively. Films are coated on p-type Si(100) wafer and ITO glass substrates by the sol-gel spin-coating method. The powder and multi-coated films are annealed at different temperature (400~$800^{\circ}C$) for phase formation and crystallization. TGA/DTA, XRD analysis, SEM and UV-visible transmission spectroscopy have been used to study the characteristics of the powder and films. XRD results show that the films are polycrystalline, anatase type and oriented predominantly to the A(101) plane. A slight shift in the d-spacing for the Pb-doped film indicates the incorporation of the Pb into $TiO_2$lattice. A shift of the absorption wavelength in the transmission spectrum towards longer wavelength has been observed about $Pb_xT_{1-x}O_2$(x = 0.1) thin film, which indicates a decrease in the bandgap of $TiO_2$upon Pb-doping.