• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.821-825
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• 2002

ZnO thick films by Sol-Gel processing were investigated electrics, optics and the sensing characteristics of CO gas. Using the znic acetate dihydrate and acetylaceton (AcAc) as a chelating agent, stable ZnO sol was synthesized. ZnO phase was crystallized through the heat-treatment at $70^{\circ}C$ for 4hrs and influenced the sensing characteristics of the electrics and CO gas by uniform particle distributions not related particle size. The samples on the alumina substrate by thick films were investigated the properties of electrics and the effect of sensing. The sensitivity was so excellent in the sample of the heat-treatment at $600^{\circ}C$ for 12hrs and good in the heat-treatment for 1hrs generally. Crystallization and volatilization of organic materials according to the change of heating treatment temperature of thick films were analyzed by TG-DTA, XRD and mirostructure of thick films were observed by SEM.

• Journal of the Korean Electrochemical Society
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• v.12 no.4
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• pp.335-341
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• 2009

Organic-inorganic hybrid sol-gel matrices were used as hosts for chloro (5, 10, 15, 20-tetraphenylporphyrinato) cobalt (III) (Co[TPP]Cl), a known ionophore for nitrite. The sol-gel precursor was prepared by the reaction of (3-isocyanopropyl) triethoxysilane with 1,4-butanediol. An appropriate amount of the anion-exchanger, tridodecylmethylammonium chloride (TDMAC) and the plasticizer, tributylphosphate (DBP) were used as membrane additives. On mixing with an acidic catalyst, the sol-state precursors slowly gelled, yielding a membrane in which the active components, Co[TPP]Cl and TDMAC, were encapsulated. The performances of the sol-gel membrane-based electrodes were compared to those of Co[TPP]Cl-based poly(vinyl chloride) (PVC) membrane electrodes. Membranes with a molar ratio of Co[TPP]Cl: TDMAC (1 : 0.1) showed reasonable response slopes toward nitrite. The response slopes were typically 53 mV/decade between $10^{-5.4}$ and $10^{-1.0}\;M$. Selectivities toward nitrite over hydrophilic and small anions such as chloride were somewhat inferior to those observed with PVC-based membranes, but selectivities over lipophilic anions were quite similar. Reduced asymmetry potentials due to protein adsorption were found to occur with the sol-gel matrix relative to PVC-based films when the sensors were employed as a detector in flow-through configuration.

• Journal of the Korean Electrochemical Society
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• v.5 no.4
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• pp.197-201
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• 2002

In this study, a gel polymer electrolyte was prepared from urethane acrylate and its electrochemical performances were evaluated. And, $LiCoO_2/GPE/graphite$ cells were prepared and their performances depending on discharge currents and temperatures were evaluated. The precursor containing $5 vol\%$ curable mixture had a low viscosity relatively. Ionic conductivity of the gel polymer electrolyte at room temperature and $-20^{\circ}C$ was ca. $5.9\times10^{-3}S{\cdot}cm^{-1}\;and\;1.7\times10^{-3}S{\cdot}cm^{-1}$, respectively. GPE showed electrochemical stability up to potential of 4.5V vs. $Li/Li^+.LiCoO_2/GPE/graphite$ cell showed a good high-rate and a low-temperature performance.

• Journal of the Korean Chemical Society
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• v.38 no.4
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• pp.276-282
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• 1994

Perovskite-type mixed oxides LaBO$_3$(B = Mn, Fe, Co) were prepared by citrate sol-gel method in $air(850^{\circ}C$, 24h). The oxygen stoichiometries and structures of these oxides were determined by XRD and TPR results as followings; LaMnO$_{3.16}$(a = 5.507, c = 13.329 $\AA$, hexagonal), LaFeO$_{3.17}$(a = 5.554, b = 5.555, c = 7.863 $\AA$, orthorhomibic), LaCoO$_{3.0}$(a = 5.436, c = 13.095 $\AA$, hexagonal). The temperature programmed reduction(TPR) experiments in static 300 torr H$_2$ atmosphere shows that the reduction reaction of LaBO$_3$(B = Mn, Fe, Co) proceeds into two stages, and thermal stabilities of these oxides decreased in the order of LaMnO$_3$ > LaFeO$_3$ > LaCoO$_3$. According to the kinetic analysis the lowest activation energy was obtained for LaCoO$_3$.

• Journal of the Korean Ceramic Society
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• v.40 no.2
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• pp.153-158
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• 2003

Self-patterning of thin films using photosensitive sol solution has advantages such as simple manufacturing process compared to photoresist/dry etching process. In this study,$La_{0.5}SR_{0.5}CoO_3$(LSCO) thin films as an electrode material for ferroelectric memories have been prepared by spin coating method using photosensitive sol solution. La-2methoxyethoxide, Sr-ethoxide, Co-2methoxyethoxide were used as starting materials. As UV exposure time to the LSCO gel thin film increased, the UV absorption peak intensity of metal${beta}$-diketonate decreased due to reduced solubility by M(metal)-O-M bond formation. Solubility difference by UV irradiation on LSCO gel thin film allows to obtain a fine patterning of thin film. The LSCO thin films annealed over$680{\circ}C$ in air showed perovskite phase and the lowest resistivity$(4{ imes}10^{-3}{Omega}cm)$ of the thin films were obtained by annealing at$740{\circ}C$.

• Proceedings of the Korean Magnestics Society Conference
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• 2001.04a
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• pp.154-155
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• 2001

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.3
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• pp.94-98
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• 2014

$LiCoO_2$ thin film has received diverse attention as cathodes material of thin-film micro-batteries. In this study, $LiCoO_2$ thin films were synthesized on Au substrates by sol-gel spin coating method and an annealing process. Their structures were studied using X-ray diffraction and Raman Spectroscopy. The particle morphologies of these thin films were observed by Scaning electron microscope. From the results of X-ray diffractometry and Raman Spectroscopy analyses, it was found that as-grown films had the structure of spinel (LT-$LiCoO_2$) and layered-Rock-salt (HT-$LiCoO_2$) at $550^{\circ}C$ and $750^{\circ}C$ respectively. The annealed films at $650^{\circ}C$ were presumed to be the mixed state of these two types. Throlugh the scanning electron microscope, It was estimated that the particle size in as-grown films at $750^{\circ}C$, were larger crystilline particle than in those at the other lower temperature and well distributed in the film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.271-278
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• 2006

Green light emitting $Zn_2SiO_4$Mn and Al co-doped $Zn_2SiO_4$:Mn phosphor were synthesized by a sol-gel method combined with a furnace firing. The luminescent properties of the sample have been investigated. We have found that the phosphor powder with uniform shape show the maximum luminescent intensity when it is prepared with sol-gel method and fired at relatively high temperature ($1100{\sim}1300^{\circ}C$).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.577-580
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• 2001

Very fine cobalt oxide ambigel powder were prepared using a unique solution chemistry associated with the sol-gel process. The mesoporous structure of the initial gel is maintained by removing fluid under conditions where the capillary forces that result extraction are either low or no existent, are either low or nonexistent. Controlling both the pore and solid architecture on the nanoscale offers a strategy for the design of supercapacitor. But $CoO_x$ have the low voltage, so we experiment using Co/PVA composite electrode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.577-580
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• 2001

Very fine cobalt oxide ambigel powder were prepared using a unique solution chemistry associated with the sol-gel process. The mesoporous structure of the initial gel is maintained by removing fluid under conditions where the capillary forces that result extraction are either low or no existent, are either low or nonexistent. Controling both the pore and solid architecture on the nanoscale offers a strategy for the design of supercapacitor. But $CoO_{x}$ have the low voltage, so we experiment using CO/PVA composite electrode.