• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.578-580
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• 2003

PEDOT [poly(3,4-ethylenedioxythiophene)] powder soluble in common organic solvent were synthesized by oxidative polymerization of EDOT (3,4-ethylene dioxythiophene) monomer using functional dopant, DEHSNa [sodium di(2-ethylhexyl)sulfosuccinate]. Transparent electrodes were made by spin casting of PEDOT/organic solvents on substrates. The electrode showed the transmittance < 90% in visible region and the surface resistance of> ${\sim}10^3\;ohm/{\square}$, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.12
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• pp.1009-1013
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• 2009

In this study, we have been synthesized the dielectric layer using pure organic and organic-inorganic hybrid precursor on flexible substrate for improving of the organic thin film transistors (OTFTs) and, design and fabrication of organic thin-film transistors (OTFTs) using small-molecule organic semiconductors with pentacene as the active layer with record device performance. In this work OTFT test structures fabricated on polymerized substrates were utilized to provide a convenient substrate, gate contact, and gate insulator for the processing and characterization of organic materials and their transistors. By an adhesion development between gate metal and PI substrate, a PI film was treated using $O_2$ and $N_2$ gas. The best peel strength of PI film is 109.07 gf/mm. Also, we have studied the electric characteristics of pentacene field-effect transistors with the polymer gate-dielectrics such as cyclohexane and hybrid (cyclohexane+TEOS). The transistors with cyclohexane gate-dielectric has higher field-effect mobility, $\mu_{FET}=0.84\;cm^2/v_s$, and smaller threshold voltage, $V_T=-6.8\;V$, compared with the transistor with hybrid gate-dielectric.

• Journal of Bio-Environment Control
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• v.10 no.2
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• pp.106-110
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• 2001

In an effort to evaluate the economic value and durability of the expanded rice hull as substrates, changes in the physical and chemical properties of material and plant growth in that substrate were studied. Using and electron microscope, the structure of used and new expanded rice hull substrate was examined. Considerable decomposition was found in the substrate which had been used one to three times. Compactness and lowered porosity in the used substrates were probably caused by decomposition. The results of cation analysis showed the possible destruction of cell wall of rice hulls. Abundant $Ca^{2+}$ in the substrates used for two to three times also indicated the possibility of decomposition. In tomato yield comparison, 15.2% more yield of tomato fruit in a new substrates indicated the negative effects of decomposition of one-time used substrates. Yield decreased in the substrates used for three times. if perlite substrates is used for three years before renewal and the cost of the perlite renewal is counted. 65.3% saving in the cost will be realized with the use of an expanded rice hull substrate. Another positive effect of the expanded rice hull substrate is the decrease of environmental contamination.n.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.150.2-150.2
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• 2015

In this study, we analyzed the electric and optical characteristics by using various deposition rate ($0.5{\AA}$, $1.0{\AA}$ and $1.5{\AA}/s$) in order to enhance the performance in organic light-emitting devices (OLED). The organic multi-layer structures were deposited with NPB ($500{\AA}$ as hole transport layer), Alq3 ($600{\AA}$ as electron transport layer and emission layer) and LiF ($8{\AA}$ as electron injection layer) via SUNIC PLUS200 on Glass/ITO substrates. In this experiment, we examined the relationship between porous state of organic deposition and mobility of the organic materials. Among the three deposition rates, $0.5{\AA}/s$ achieved the highest performance of (10,786cd/m2, 4.387cd/A) comparing with that of $1{\AA}/s$ (7,779cd/m2, 3.281cd/A) and $1.5{\AA}/s$ (5,167cd/m2, 2.693cd/A). We confirmed that low deposition rate helps to arrange organic materials densely and to move easily another atomic location using inter-chain transporting by orbital overlap.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.473-473
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• 2011

In recent years, organic thin film transistors OTFTs based on conductive-conjugated molecules have received significant attention. We report a fabrication of organic single crystal nanowires that made on Si substrates by liquid bridge-mediated nanotransfer molding (LB-nTM) with polyurethane acrylate (PUA) mold. LB-nTM is based on the direct transfer of various materials from a stamp to a substrate via a liquid bridge between them. In liquid bridge-transfer process, the liquid layer serves as an adhesion layer to provide good conformal contact and form covalent bonding between the organic single crystal nanowire and the Si substrate. Pentacene is the most promising organic semiconductors. However pentacene has insolubility in organic solvents so pentacene OTFTs can be achieved with vacuum evaporation system. However 6, 13-bis (triisopropylsilylethynyl) (TIPS) pentacene has high solubility in organic solvent that reported by Anthony et al. Furthermore, the substituted rings in TIPS-pentacene interrupt the herringbone packing, which leads to cofacial ${\pi}-{\pi}$ stacking. The patterned TIPS-Pentacene single crystal nanowires have been investigated by Atomic force microscopy (AFM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and electrical properties.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.3
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• pp.215-218
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• 2011

A novel design of gas sensor using Ga-doped ZnO (GZO) thin films which are deposited on low temperature co-fired ceramic (LTCC) substrates is presented. The LTCC substrates with thickness of 400 ${\mu}m$ are fabricated by laminating 12 green tapes which consist of alumina and glass particle in an organic binder. The GZO thin films with different thickness are deposited on LTCC substrates, by RF magnetron sputtering method. The microstructure and sensing properties of GZO gas sensing films are analyzed as a function of the film thickness. The films are well crystallized in the hexagonal (wurzite) structure with increasing thickness. The maximum sensitivity of 3.49 is obtained at 100 nm film thickness and the fastest 90% response time of 27.2 sec is obtained at 50 nm film thickness for the operating temperature of $400^{\circ}C$ to the $NO_2$ gas.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.192-192
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• 2006

Organic/organic and organic/inorganic multilayer films composed of organic polyelectrolytes (PE) and inorganic nanoparticles/platelets were prepared from the layer-by-layer (LbL) deposition using both spinning and dipping. The difference in both LbL methods is quantitatively compared in terms of internal layer ordering and physical properties of the multilayered films. Additionally, we suggest that the patterned multilayer films can be easily prepared by the combination of the spin SA and the lift-off method. Freestanding films were also prepared with the LbL deposition on low energy substrates, which allows the detailed analysis of composition within the films. Other LbL thin films prepared with block copolymer micelles will be discussed.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.315-315
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• 2006

A variable surface coating with the potential to fulfill the requirements of industry will be presented. Via controlled radical polymerization methods from a functionalized Polymethylsilsesquioxane delivers an inorganic-organic block copolymer, which can be easily modified and tuned for different applications. Spin coated or dip coated on various substrates show promising results. By using different block copolymers the contact angle on a silicon wafer can be varied in a range of $90^{\circ}\;up\;to\;145^{\circ}$ After curing and complete condensation a perfect adhesion on glasses, plastics and metals is achieved.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.521-522
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• 2008

An etch-less simple method was developed to fabricate two-dimensional nanostructures on glass substrate directly by using UV curable polymer resin and UV nanoimprint lithography in order to improve output coupling efficiency of OLEDs. OLEDs integrated on nanoimprinted substrates enhanced electro-luminance intensity by up to 50% compared with the conventional device.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.343-343
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• 2011

ZnO has been introduced as one of the good candidates for next generation opto-electronics. Recently, ZnO is known to be suitable for the transparent electrode in organic solar cells and light emitting devices. The contact with n-type organic material has been studied due to the n-type properties of ZnO. However, the surface of ZnO has shown different electronic property with respect to its surface orientation. Therefore, it is presumed that there are differences in the interfacial electronic structures between organic materials and ZnO with different orientation. Therefore, it is required to classify the interfacial electronic structures according to the surface orientation of ZnO. In this study, we measured the interfacial electronic structures between the ZnO substrate having various orientations and a typical n-type organic material, tris-(8-hydroxyquinoline) aluminum (Alq3). In-situ x-ray and ultraviolet photoelectron spectroscopy measurements revealed the interfacial electronic structures. We found the changes in the electronic structures with respect to the orientation of ZnO substrate and it could be used to improve the contact between ZnO and Alq3.