• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집
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• pp.57-59
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• 2005

Ploycrystalline $Pb(Zr_{0.5},Ti_{0.5})O_3$ and $BaTiO_3$ powder were prepared by sol-gel process. The alumina substrate were sintered at $1400^{\circ}C$ with bottom electrode of Pt for 2 hours. The Pb(Zr0.5,Ti0.5)O3 / BaTiO3 multilayered thick films with laminating times were fabricated on alumina substrate by screening printing method. The obtained thick films were sintered at $800^{\circ}C$ with upper electrode of Ag paste for 1 hour. Structural properties of Pb(Zr0.5,Ti0.5)O3 / BaTiO3 multilayered thick films were investigated. As a result of the Differential Thermal Analysis(DTA) of Pb(Zr0.5,Ti0.5)O3, exothermic peak was observed at around $650^{\circ}C$. The X-ray diffraction (XRD) patterns indicated that BaTi03 and Pb(Zr0.5,Ti0.5)O3 phases and porosities were formed in the interface of Pb(Zr0.5,Ti0.5)O3 / BaTiO3 multilayered thick films.

• 한국세라믹학회지
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• 제32권11호
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• pp.1262-1268
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• 1995

Photoelectrochemical properties of p-GaAs electrode have been investigated. I-V characteristic shows that the cathodic photocurrent is observed at -0.7 V vs. SCE. The photoresponse at near 870~880nm wavelength indicates that the photogenerated carriers contibuted to the observed current. The maximum converson efficiency of 35% is obtained for a Xe lamp light source at 400nm. In C-V relation, capacitance peaks appeared at the frequencies of 100Hz and 300Hz due to the activation of the interfacial states which exist at the energy level corresponding to the one-third of the GaAs band gap. The difference of about 1.1V between flatband potential (Vfb) from the Mott-Schottky method and onset voltage from I-V curve is observed due to the trap of carriers at the interfacial states in the boundary between GaAs and electrolyte. In case of WO3 deposited p-GaAs electrode, higher positive onset current and photocurent density are obtained. This can be explained by the fact that carriers are generated by light penetrated into the WO3 thin flm as well as p-GaAs substrate and then move into the electrolyte effectively.

• 대한의용생체공학회:의공학회지
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• 제34권1호
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• pp.34-39
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• 2013

For the biocompatibility test of implantable devices or for the sensitivity evaluation of biomedical sensors, it is required to understand the mechanism of the protein adsorption and the interaction between the adsorbed proteins and cells. In this study, the adsorption of proteins in a cell culture medium with fetal bovine serum onto an indium tin-oxide electrode was characterized by using linear sweep voltammetry and impedance spectroscopy. We immersed the fabricated ITO electrodes in the culture medium for 30, 60, or 90 min, and then measured the electrochemical properties of electrodes with 10 mM $Fe(CN){_6}^{3-/4-}$ and 0.1 M KCl electrolyte. With an increase of contacting time, the anodic peak current was decreased and the charge transfer resistance was increased. However, both parameters were recovered to the values before contact with the medium after the treatment of Trypsin/Ethylenediaminetetraacetic acid hydrolyzing proteins.

• 한국전기전자재료학회논문지
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• 제19권6호
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• pp.563-567
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• 2006

Indium tin oxide (ITO) used as an electrode in organic light emitting diodes (OLEDs) and organic thin film transistors (OTFTs) was modified by a self-assembled monolayer (SAM). For device fabrication, surface of the ITO was modified by immersion in a solution including various phosphonic acid at room temperature in order to increase work function of an electrode. The work function of ITO with SAM was measured by Kelvin probe. Work function increase of 0.88 eV was observed in ITO with various SAM. Therefore, ohmic contact is achieved in an interface between ITO and organic semiconductors (pentacene). We analyzed the origin of work function increase of ITO with SAM by X-ray photoelectron spectroscopy. We confirmed that increase of oxygen bonding energy attributed to increase the work function of ITO. These results suggested that ITO with the SAM gives a high possibility for high performance of OLEDS and OTFTs.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2022-2024
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• 2005

Electrical double-layer capacitor (EDLC) is an electrochemical energy storage device in which electric charges only accumulated by a pure electrostatic attraction force are stored on the electrolyte-electrode interface in a form of double layer and separated by the electrolyte. The composite was prepared by mixing nanosize $TiO_2$ and activated carbon through a means of ultrasonic vibration in ethanol solution for 30 min in various mass ratios of $AC:TiO_2$ to form activated carbone-semiconducting oxide composites. Either 1.0 M $LiClO_4/EC-DEC$ or $Et_4NBF_4$/EC-DEC was used as the electrolyte. It was found that with modification of $TiO_2$, the specific capacitance of activated carbon measured at $1mA/cm^2$ was increased from 40 to 50 F/g. This method is unique in comparison the conventional method because it uses semiconducting TiO2 other than electrochemically active materials such as $RuO_2$. The increase in specific capacitance could be attributed to the decrease in electric polarization, caused by the introduction of $RuO_2$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.1960-1961
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• 2005

Ploycrystalline $Pb(Zr_{0.5},Ti_{0.5})O_3$ and $BaTiO_3$ powder were prepared by sol-gel process. The alumina substrate were sintered at $1400^{\circ}C$ with bottom electrode of Pt for 2 hours. The Pb(Zr0.5, Ti0.5)O3/BaTiO3 multilayered thick films with laminating times were fabricated on alumina substrate by screening printing method. The obtained thick films were sintered at $800^{\circ}C$ with upper electrode of Ag paste for 1 hour, Structural properties of Pb(Zr0.5,Ti0.5)O3/BaTiO3 multilayered thick films were investigated. As a result of the Differential Thermal Analysis(DTA) of Pb(Zr0.5,Ti0.5)O3, exothermic peak was observed at around $650^{\circ}C$. The X-ray diffraction (XRD) patterns indicated that BaTiO3 and Pb(Zr0.5,Ti0.5)O3 phases and porosities were formed in the interface of Pb(Zr0.5,Ti0.5)O3 / EaTiO3 multilayered thick films.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.205-208
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• 1994

The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li secondary battery. PEO-$LiClO_4$ electrolyte with plasticizer is very unstable. Passivation phenomena in polymer electrolyte cell was described by the SPL model. The time dependance of the impedance indicates that a passivation layer grows rapidly on the Li surface. However, the growing of passivation layer on the Li surface can be restrained by addition of zeolite to the PEO electrolyte. It suggested that addition of zeoliteto to the PEO-$LiClO_4$ electrolyte effectively controls the formation of a passivation layer on Li electrode.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.140-143
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• 2003

BST thin films have a good thermal-chemical stability, insulating effect and variety of phases. However, BST thin films have problems of the aging effect and mismatch between the BST thin film and electrode. Also, due to the high defect density and surface roughness at grain boundarys and in the grains, which degrades the device performances. In order to overcome these weakness, we first applied the chemical mechanical polishing (CMP) process to the polishing of ferroelectric film in order to obtain a good planarity of electrode/ferroelectric film interface. BST ferroelectric film was fabricated by the sol-gel method. And then, we compared the structural characteristics before and after CMP process of BST films. We expect that our results will be useful promise of global planarization for FRAM application in the near future.

• Bulletin of the Korean Chemical Society
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• 제22권7호
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• pp.709-715
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• 2001

We have been studied photosensitization mechanism's additive effect, of perylene 3,4,9,10-tetracarboxyl-diimide and X-phthalocyanine (charge generation materials), using the photochemical and photoelectrochemical approach. It was found that the photoreceptor on the excited state reacts with metal oxide, which creates the charge transfer on the interface of SnO2/electrolyte. In the electrode (X5P1) made of five X-phthalocyanine and single perylene 3,4,9,10-tetracarboxyldiimide layers, the cathodic photocurrent of X-phthalocyanine in the 400-600 nm region was increased by the addition of perylene 3,4,9,10-tetracarboxyldiimide. The maximum wavelength of fluorescence of perylene 3,4,9,10-tetracarboxyldiimide showed no dependence on the temperature. The addition of 4-dibenzylamino-2-methylbenzaldehyde diphenylhydrazone known as charge transport material was represented as decreasing photocurrent for X-phthalocyanine and perylene 3,4,9,10-tetracarboxyldiimide, respectively. In the electrode (X1P1) made of single X-phthalocyanine and single perylene 3,4,9,10-tetracarboxyldiimide layers, an anodic photocurrent of about 10.5 nA was generated by addition of hydroquinone at 550 nm. And the characteristic of photoinduced discharge was shown to decrease by a factor of 5 and the speed of dark decay was increased by a factor of 1.2.

• Journal of Ceramic Processing Research
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• 제19권5호
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• pp.413-418
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• 2018

All-solid-state lithium batteries (ASSBs) using inorganic sulfide-based solid electrolytes are considered prospective alternatives to existing liquid electrolyte-based batteries owing to benefits such as non-flammability. However, it is difficult to form a favorable solid-solid interface among electrode constituents because all the constituents are solid particles. It is important to form an effective electron conduction network in composite cathode while increasing utilization of active materials and not blocking the lithium ion path, resulting in excellent cell performance. In this study, a mixture of fibrous VGCF and spherical nano-sized Super P was used to improve rate performance by fabricating valid conduction paths in composite cathodes. Then, composite cathodes of ASSBs containing 70% and 80% active materials ($LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$) were prepared by a solution-based process to achieve uniform dispersion of the electrode components in the slurry. We investigated the influence of binary carbon additives in the cathode of all-solid-state batteries to improve rate performance by constructing an effective electron conduction network.