• Korean Journal of Materials Research
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• v.31 no.1
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• pp.8-15
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• 2021

Transparent, photocatalytic, and self-cleaning TiO2 thin film is developed by TiO2 sol-gel coating on glass and polycarbonate (PC) substrates. Acetyl acetone (AcAc) suppresses the precipitation of TiO2 by forming a yellowish (complex) transparent sol-gel. XPS analysis confirms the presence of Ti2p and O1s in the thin films on glass and PC substrates. The TiO2-sol is prepared by stabilizing titanium (IV) isopropoxide (TTIP) with diethylamine and methyl alcohol. The addition of AcAcsilane coupling solution to the TiO2-sol instantaneously turns to yellowish color owing to the complexing of titanium with AcAc. The AcAc solution substantially improves the photocatalytic property of the TiO2 coating layer in MB solutions. The coated TiO2 film exhibits super hydrophilicity without and with light irradiation. The TiO2 thin film stabilized by adding 8.7 wt% AcAc shows the highest photo-degradation for methylene blue (MB) solution under UV light irradiation. Also, the optimum photocatalytic activity is obtained for the 8.7 wt% AcAc-stabilized TiO2 coating layer calcined at 450 ℃. The thin-films on glass exhibit fast self-cleaning from oleic acid contamination within 45 min of UV-light irradiation. The appropriate curing time at 140 ℃ improves the anti-fogging and thermal stability of the TiO2 film coated on PC substrate. The watermark-free PC substrate is particularly beneficial to combat fogging problems of transparent substrates.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.9
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• pp.681-684
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• 2010

The $TiO_2$/ZnS/Ag/ZnS/$TiO_2$ multilayered structure for the transparent electrodes in plasma display panel was designed by essential macleod program (EMP) and the multilayered film was deposited on a glass substrate by direct-current (DC)/radio-frequency (RF) magnetron sputtering system. During film deposition process, the Ag layer in $TiO_2$/Ag/$TiO_2$ structure became oxidized and the filter characteristic was degraded easily. In this study, ZnS layer was adopted as a diffusion blocking layer between $TiO_2$ and Ag to prevent the oxidation of Ag layer efficiently in $TiO_2$/ZnS/Ag/ZnS/$TiO_2$ structure. Based on the AES depth profiling analysis, the Ag layer was effectively protected by the ZnS layer as compared with the $TiO_2$/Ag/$TiO_2$ multilayered films without ZnS as an antioxidant layer. The 3 times stacked $TiO_2$/ZnS/Ag/ZnS/$TiO_2$ films have low sheet resistance of $1.22{\Omega}/{\square}$ and luminous transmittance was as high as 62% in the visible ranges.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.511-511
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• 2007

Low-emissivity (low-e) coatings with visible transparency have attracted increased interest m reducing heat radiation loss through window panes from ecological and sustainable aspects. $TiO_2$-silver transparent thin films for low-e have good properties for UV and IR blocking as well as photocatalyst compared to that with commercial UV blocking films such as fluorine doped oxide (FTO), antimony doped tin oxide (ATO), etc. In this study, transparent $TiO_2$-silver thin films were prepared by successive ink-jet printing of commercial nano silver and $TiO_2$ sol. The $TiO_2$ sol, as ink for ink-jet printing, were synthesized by hydrothermal process in the autoclave externally pressurized with $N_2$ gas of 200 bar at $120^{\circ}C$ for 10 hrs. The synthesized $TiO_2$ sols were all formed with brookite phase and their particle size was several to 30 nm. At first nano sized silver sol was coated on glass substrate, after that $TiO_2$ sol was coated by ink-jet printing. With increasing coating thickness of $TiO_2$-silver multilayer by repeated ink-jet coating, the absorbance of UV region (under 400nm) and IR region (over 700nm) also increase reasonably, compared to that with commercial UV blocking films.

• Bulletin of the Korean Chemical Society
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• v.19 no.1
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• pp.107-109
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• 1998

The $SnO_2$, Sn-doped $In_2O+3\; and \;Ce-doped\; TiO_2$ films have been prepared by RF sputtering method, and their opto-electrochemical properties were investigated in view of the applicability as counter electrodes in the electrochromic window system. These oxide films could reversibly intercalate $Li^+$ ions owing to the nanocrystalline texture, but remained colorless and transparent. The high transmittance of the lithiated films could be attributed to the prevalence of the $Sn^{4+}/Sn^{2+}\; and\; Ce^{4+}/Ce^{3+}$ redox couples having 5s and 6s character conduction bands, respectively. For the Ce-doped $TiO_2$ film, $(TiO_2)_{1-x}(CeO_2)_x$, an optimized electrochemical reversibility was found in the film with the composition of x = 0.1.

• Journal of the Korean Society for Heat Treatment
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• v.28 no.6
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• pp.296-299
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• 2015

$In_2O_3/Ti$ bi-layered films were deposited on glass substrate at room temperature with radio frequency (RF) and direct current (DC) magnetron sputtering to consider the effect of Ti buffer layer on the electrical and optical properties. In a comparison of figure of merit, $In_2O_3$ 90 nm/Ti 10 nm thin films show the higher opto-electrical performance of $3.0{\times}10^{-4}{\Omega}^{-1}$ than that of the $In_2O_3$ single layer films ($2.6{\times}10^{-4}{\Omega}^{-1}$). From the observed results, it is supposed that the $In_2O_3\;90nm/TiO_2$ 10 nm bi-layered films may be an alternative candidate for transparent electrode in a transparent thin film transistor device.

• Journal of the Korean institute of surface engineering
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• v.40 no.4
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• pp.190-196
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• 2007

Dye sensitized solar cells(DSSC) are the most promising future energy resource due to their high energy efficiency, low production cost, and simple manufacturing process. But one problem in DSSC is short life time compared to silicon solar cells. This problem occurred from photocatalytic degradation of dye material by nanometer sized $TiO_2$ particles. To prevent dye degradation as well as to increase its life time, the transparent coating film is needed for UV blocking. In this study, we synthesized nanometer sized $TiO_2$ particles in sols by increasing its internal pressure up to 200 bar in autoclave at $120^{\circ}C$ for 10 hrs. The synthesized $TiO_2$ sols were all formed with brookite phase and their particle size was several nm to 30 nm. Synthesized $TiO_2$ sols were coated on the backside of fluorine doped tin oxide(FTO) glass by ink jet printing method. With increasing coating thickness by repeated ink jet coating, the absorbance of UV region (under 400 nm) also increases reasonably. Decomposition test of titania powders dispersed in 0.1 mM amaranth solution covered with $TiO_2$ coating glass shows more stable dye properties under UV irradiation, compared to that with as-received FTO glass.

• Korean Journal of Optics and Photonics
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• v.13 no.4
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• pp.363-369
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• 2002

We have designed conductive transparent filters using a low-emissivity coating such as [dielectric|Ag|dielectric] for display applications. The design is the repetition of [$TiO_{2}$|Ti|Ag |$TiO_{2}$] to increase the transmittance in the visible and decrease the transmittance in the near IR. The conductive transparent filters are deposited by a radio frequency(RF) magnetron sputtering system. The optical, structural and electrical properties of the filters were investigated and the optical spectra are compared with simulated spectra. The thickness of the deposited Ag films is above 13 ㎚ to increase the conductivity and that of $TiO_{2}$ films is 24 ㎚ to increase the transmittance in the visible range. Ti blockers are employed to prevent the Ag films from being oxidized by an oxygen gas during the reactive sputtering process. Also, it is shown that the thicker Ti film is necessary as the period increases. Finally, a filter with repetition of the basic structure three times shows the better cut-off near infrared(NIR) and the sheet resistance as low as 2Ω/□ which is enough to shield an unnecessary electromagnetic waves for a display panel.

• Korean Journal of Materials Research
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• v.21 no.7
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• pp.371-376
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• 2011

We report on the effects of $TiO_2$ doping power on the characteristics of multicomponent $TiO_2$-ITO (TITO) electrodes prepared by a multi-target sputtering system with tilted cathode guns. Both as-deposited and annealed TITO electrodes showed linearly increased sheet resistance and resistivity with increasing $TiO_2$ doping power. However, the TITO electrodes exhibited a fairly high optical transmittance regardless of the $TiO_2$ doping power due to the high transparency of the $TiO_2$. Although the annealed TITO showed much lower sheet resistance and resistivity relative to the as-deposited samples, the electrical properties of the annealed samples exhibited similar dependence on the $TiO_2$ power to the as-deposited samples. In addition, it was found that doping of an anatase $TiO_2$ in the ITO electrode prevented the preferred (222) orientation of the TITO electrodes. Although the TITO electrode showed higher sheet resistance and resistivity than that of the pure ITO electrode, it offers a very smooth surface and usage of a low-cost Ti element. It is thus considered a promising multicomponent transparent conducting electrode for cost-efficient flat panel displays and photovoltatics.

• Journal of the Korean Vacuum Society
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• v.5 no.2
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• pp.147-155
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• 1996

Optical properties of $TiO_2/M/Ag/M/TiO_2$ films have been changed with the diffusion barrier metal M. Optimum opticla properties of $TiO_2/M/Ag/M/TiO_2$ as the transparent heat mirror film, could be obtained with Ti among diffusion barrier metals of Ti, Cu, Zr and Al. $TiO_2/M/Ag/M/TiO_2$ film, which was fabricated by sputtering of 18 nm-thick $TiO_2$ and Ag, and 4nm-thick Ti, showed maximum transimittance of 89% at visible wavelength and infrared reflectance of 97% at wavelength of 3000 nm. Optical properties of this film was not degraded by Xenon-sunshine weather test for 240 hours. For specimens with barrier layers of Cu, Zr, and Al, degradation of optical properties by weather test was increased in a sequence of films with Cu, Zr, and Al barrier layers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.1-6
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• 2017

Functional coatings, such as anti-reflection and self-cleaning, are frequently applied to cover glass for photovoltaic applications. Anti-reflection coatings made of mesoporous silica film have been shown to enhance the light transmittance. $TiO_2$ photocatalyst films are often applied as a self-cleaning coating. In this study, transparent hydrophobic anti-reflective and self-cleaning coatings made of $SiO_2/TiO_2$ thin layers were fabricated on a slide glass substrate by the sol-gel and dip-coating processes. The morphology of the functional coatings was characterized by field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). The optical properties of the functional coatings were investigated using an UV-visible spectrophotometer. Contact angle measurements were performed to confirm the hydrophobicity of the surface. The results showed that the $TiO_2$ films exhibit a high transmittance comparable to that of the bare slide glass substrate. The $TiO_2$ nanoparticles make the film more reflective and lead to a lower transmittance. However, the transmittance of the $SiO_2/TiO_2$ thin layers is 93.5% at 550 nm with a contact angle of $110^{\circ}$, which is higher than that of the bare slide glass (2.0%).