• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.224-224
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• 2015

Gel have enormous applicable region due to inherently high stretchability and bio-compatibility. Here, we fabricated highly stretchable electronic conductive organogels which have long-term stability in environment. By introducing a dialysis step which can incorporate conducting polymer, PEDOT, on the procedure of gel synthesis, residual ions inside the gel were removed. In addition, we replaced the water with organic solvent, EG, inside the gels which is high stability in air. Unlike conventional hydrogels, there are no ionic conduction occurred and electrochemically driven current was prevented during electrical voltage was applied. The fabricated organogels are hardly dried during air exposure, and only electrically conductive without any electrochemical reaction at even high voltage. In order to utilize as stretchable conductor, we demonstrated a LED array circuit using the conductive organogels as electrical interconnects. It was successfully operative even stretched up to 300% strain.

• Transactions on Electrical and Electronic Materials
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• v.13 no.5
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• pp.241-244
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• 2012

Antimony doped tin oxide (ATO) thin films on glass substrate were prepared by the chemical solution deposition (CSD) method, using sol-gel solution synthesized by non-alkoxide precursors and the sol-gel route. The crystallinity and electrical properties of ATO thin films were investigated as a function of the annealing condition (both annealing environments and temperatures), and antimony (Sb) doping concentration. Electrical resistivity, carrier concentration, Hall mobility and optical transmittance of ATO thin films were improved by Sb doping up to 5~8 mol% and annealing in a low vacuum atmosphere, compared to the undoped tin oxide counterpart. 5 mol% Sb doped ATO film annealed at $550^{\circ}C$ in a low vacuum atmosphere showed the highest electrical properties, with electrical resistivity of about $8{\sim}10{\times}10^{-3}{\Omega}{\cdot}cm$, and optical transmittance of ~85% in the visible range. Our research demonstrates the feasibility of low-cost solution-processed transparent conductive oxide thin films, by controlling the appropriate doping concentration and annealing conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.320-320
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• 2007

Nowadays, ZnO thin films are investigated as transparent conductive electrodes for use in optoelectronics devices including flat displays, thin films transistors, solar cells because of their unique optical and electrical properties. For the use as transparent conductive electrodes, a film has to have low resistivity, high absorption in the ultra violent light region and high optical transmission in the visible region. Different technologies such as electron beam evaporation, chemical vapor deposition, laser evaporation, DC and RF magnetron sputtering and have been reported to produce thin films of ZnO with adequate performance for applications. However, highly transparent and conductive doped-ZnO thin films deposited by a metal-organic decomposition method have not been reported before. In this work, the effect of dopant concentration, heating treatment and annealing in areducing atmosphere on the structure, morphology, electrical and optical properties of ZnO thin films deposited on glass substrates by a Sol-gel method are investigated.

• Proceedings of the KAIS Fall Conference
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• 2004.06a
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• pp.96-99
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• 2004

A new proton conductive inorganic-organic hybrid membrane doped with $H_3PO_4$ was fabricated via sol-gel process wit 3- glycidoxypropyltrimethoxysilane(GPTMS), 3-aminopropyltriethoxysilane(APTES) and tetraethoxysilane(TEOS) asprecursors. Theproto conductivity of about 3.0$\times10^{-3}S/cm$ was obtained at $120^{\circ}C$ under $50\%$ relative humidity (R.H). DTA curves showed that the thermal stability of the membrane is significantly enhanced by the presence of $SiO_2$ framework up to $250^{\circ}C$. SEM and XRD revealed that the gel is microporou and amorphous. The addition of APTES improved the conductivity of the membranes and the effect of the APTES on the conductivity was also discussed in this paper.

• Current Photovoltaic Research
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• v.2 no.3
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• pp.110-114
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• 2014

We propose a low temperature sol-gel ZnO/Ag nanowire composite thin film to fulfill low temperature and low cost requirements, which are essential criteria in future flexible electronic devices. In this proposed thin film, Ag nanowire plays the role of electrical conduction, and sol-gel ZnO provides a structural medium with a high visible transmittance. Low temperature restriction in the sol-gel fabrication process prevents sufficient oxidation of Zn acetate precursors, which were solved by a post-coating treatment with ultraviolet light irradiation. Composite thin film formation was performed by spin coating methods with a mixed precursor solution or in a sequential manner. We obtained an average visible transmittance larger than 85% and a sheet resistance smaller than $50{\Omega}/sq$. After optimization in a fabricated composite transparent conductive thin film with the thickness around 100 nm. Similar experimental demonstration in a flexible substrate (polyethyleneterephthalate) was successful, which implies a promising application opportunity of this technology.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2007-2010
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• 2008

Vanadium pentoxide ($V_2O_5$) powder was prepared and mixed with Molybdenum Oxides ($MoM_3$) to form Mo-doped and -undoped $VO_2$ films by a sol-gel method on graphite conductive substrates. X-Ray diffraction (XRD) and scanning electron microscopy (SEM) was used to investigate the chemical compositions and microstructures of the Mo-doped and -undoped $VO_2$ films. The variation of electrical resistance was measured as a function of temperature and stoichiometric composition between vanadium and molybdenum. In this study, it was found that Mo-doped and -undoped $VO_2$ shows the typical negative temperature coefficient (NTC) behavior. As the amount of the molybdenum increases, the electrical resistance of Modoped $VO_2$ film gets reduced under the transition temperature and a linear decrease in the transition temperature is observed. From these experimental results, we can conclude that the electrical resistance behavior with temperature change of $VO_2$ films can be utilized as a self-heating source with the electrical current flowing through the graphite substrate.

• Corrosion Science and Technology
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• v.6 no.2
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• pp.44-49
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• 2007

Dimensionally stable anodes have been widely used to cathodically protect the metallic materials in corrosive environments including concrete structure as the insoluble anode. Lifespan of the anode for concrete construction can be determined by NACE TM0294-94 method. Lifespan of conductive oxide electrode would be affected by thermal treatment condition in the process of sol-gel coatings. This work aims to evaluate the effect of thermal treatment temperature on the lifespan of the $RuO_{2}$ electrode. $450^{\circ}C$ treated conductive oxide electrode showed the excellent properties and its lifespan was evaluated to be over 88 years in 3% NaCl, 4% NaOH, and simulated pore water. This behavior was related to the formation of $RuO_{2}$.

• Journal of the Korean Ceramic Society
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• v.42 no.2 s.273
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• pp.77-80
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• 2005

A series of proton conductive composite membranes based on poly(vinyl alcohol) and phosphosilicate gels powders were successfully prepared. The proton conductivity of these composite was attributed to the phosphosilicate gel, which derived from tetraethoxysilane and phosphoric acid by sol-gel process at a molar ratio of P/Si = 1.5. The proton conductivity increased with increasing both the content of phosphosilicate gel and relative humidity. Temperature dependence of conductivity showed a Vogel-Tamman-Fulcher type behavior, indicating that proton was transferred through a liquidlike phase formed in micropores of phosphosilicate gel. The high conductivity of 0.065 S/cm with a membrane containing 60 wt$\%$ of the gel was obtained at $60^{\circ}C$ at $90\%$ relative humidity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.1039-1042
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• 2001

A method for designing antireflection (AR) and antistatic (AS) films by the use of conducting polymer as an electrically conductive transparent layer is proposed. The conducting AR film is composed of four-layer with alternating high and low refractive index layer: silicon dioxide (n=1.44) and titanium dioxide (n=2.02) prepared at low temperature by sol-gel method are used as the low and high refractive index layer, respectively. The 3,4-polyethylenedioxythiophene (PEDOT) which has the sheet resistance of 10$^4$$\Omega$/$\square$ is used as a conductive layer. Optical constant of ARAS film was measured by the spectroscopic ellipsometer and from the measured optical constants the spectral properties such as reflectance and transmittance were simulated in the visible region. The reflectance of ARAS films on glass substrate was below 0.8 %R and the transmittance was higher than 95 % in the visible wavelength (400-700 nm). The measured AR spectral properties was very similar to its simulated results.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.1
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• pp.55-60
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• 2018

Transparent conductive thin films (TCFs) are essential materials for solar cells, organic light-emitting diodes, and display panels. Indium tin oxide (ITO) is one of the most widely used commercial materials to create TCFs'; however, new materials that can possibly replace ITO at a lower cost and/or those possessing mechanical flexibility are urgently needed. Silver nanowire (AgNW) is one of those promising materials, as it is less expensive and possesses superior mechanical flexibility as compared to ITO. We used AgNW and sol-gel ZnO to fabricate composite thin films by spray coating. We propose two spray-coating methods: the 'metal-organic chemical vapor deposition (MOCVD)/AgNW' method and the Mixture method. These two methods are expected to be commercialized for high-quality and low-cost products, respectively.