• Journal of Integrative Natural Science
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• v.6 no.4
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• pp.211-214
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• 2013

In this study, in order to investigate how consecutive treatments of glass surface with HF acid and water vapor/Ar plasma affect the quality of 3-aminopropyltriethoxysilane self-assembled monolayer (APS-SAM), poly(3,4-ethylenedioxythiophene) (PEDOT) thin films were vapor phase-polymerized immediately after spin coating of FeCl3 and poly-urethane diol-mixed oxidant solution on the monolayer surfaces prepared at various treatment conditions. For the film characterization, various poweful tools were used, e.g., FE-SEM, an optical microscope, four point probe, and a contact angle analyzer. The characterization revealed that HF treatment is not desirable for the synthesis of a high quality PEDOT thin film via vapor phase polymerization method. Rather, sole treatment with plasma noticeably improved the quality of APS-SAM on glass surface. As a result, a highly dense and smooth PEDOT thin film was grown on uniform oxidant film-coated APS monolayer surface.

• Journal of Information Display
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• v.11 no.4
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• pp.144-148
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• 2010

In this paper, vertically aligned (VA) liquid crystal (LC) modes were investigated using the alkyl chain ordering effect of self-assembled monolayers (SAMs) prepared on the anisotropic inorganic surface. On the anisotropic surface prepared through oblique ion beam irradiations, the SAM molecules are adsorbed, producing macroscopic alkyl chain ordering, which can determine the pretilt direction of the vertically aligned LC molecules through the intermolecular interactions on the surface.

• Bulletin of the Korean Chemical Society
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• v.23 no.5
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• pp.699-704
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• 2002

We characterized nanoelectrode arrays prepared from self-assembled monolayers (SAMs) by adsorption from a solution containing thiolated $\beta$-cyclodextrin ($\beta$-CD) and n-alkanethiol on the gold electrode surface, using electrochemical methods. While the framework, the n-hexadecanethiol SAM, effectively blocked electron transfer between the electrode surface and solution-phase redox probe molecules, the $\beta$-CD cavities isolated in the forests of n-hexadecanethiol molecules were shown to act as an ultramicroelectrode array. The shapes of cyclic voltammograms of probe molecules were related to the number densities of $\beta$-CD molecules within the monolayer films. Probe molecules that have the correct combination of physical and chemical characteristics were shown to effectively penetrate the framework through the $\beta$-CD pores and exchange electrons with the electrode surface.

• Journal of Ceramic Processing Research
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• v.19 no.5
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• pp.361-368
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• 2018

We investigated the interfacial properties of fluorocarbon self-assembled monolayers (FC-SAMs) with different alkyl chain lengths. It was found that the substrate characteristics were changed rapidly with the fabrication time and temperature of the SAM. FC-3SAM, which has the shortest alkyl chain in this study, showed a contact angle of $54.1^{\circ}$ when it was fabricated in an electric oven at $60^{\circ}C$ for the first minute. The FC-3SAM showed a contact angle of up to $76.9^{\circ}$ when it was fabricated in an electric oven at the same temperature condition for 180 minutes. FC-10SAM, which has the longest alkyl chain in this study, showed a contact angle of $64.7^{\circ}$ when it was fabricated at a temperature condition of $60^{\circ}C$ for 1 minute, and a contact angle of $98.7^{\circ}C$ at a temperature condition of $60^{\circ}C$ for 180 minutes. It was found that the FC-10SAM shows an increased contact angle and hydrophobic properties due to a well-aligned molecular structure resulting from a strong van der Waals force. In contrast, the FC-3SAM shows a small contact angle due to the intermolecular disorder resulting from a weak van der Waals force. The average roughness of FC-SAMs was investigated using AFM. The surface roughness of FC-SAMs, which verifies the results of contact angle, was confirmed. At a fabrication time of 120 minutes, the FC-10SAM showed an improvement in average roughness by 62% compared to that of FC-3SAM due to its good alignment.

• Journal of Sensor Science and Technology
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• v.23 no.5
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• pp.295-298
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• 2014

A novel approach to fabricating high-performance glucose sensors is reported, which is based on the process of self-assembled monolayers (SAMs). In this study, we have particularly used ${\alpha}$-lipoic acid (LA) SAMs for the glucose sensors. To our best knowledge, this study is the first one to use LA as SAMs for this purpose. N-hydroxysuccinimide (NHS) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) were deliberately attached at the same time on the LA SAM. Then, glucose oxidase ($GO_X$) and horseradish peroxidase (HRP) were sequentially immobilized. Thus, the HRP/$GO_X$/NHS-EDC/LA-SAM/Au/Cr/glass working electrode was developed. The glucose-sensing capability of the fabricated sensor was systematically measured by the use of cyclic voltammetry in the range of 1-30 mM glucose in phosphate-buffered saline. The result showed a good sensitivity, that is, as high as $27.5{\mu}A/(mM{\cdot}cm^2)$. This result conspicuously demonstrates that LA can be one of promising substances for use as SAMs for accurately monitoring trace levels of glucose concentration in human blood.

• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.289-292
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• 2012

Au electrodes modified with self-assembled monolayers (SAMs) were used to control the work function of source/drain electrodes in triethylsilylethynyl anthradithiophene (TES ADT)-based organic thin film transistors (OTFTs). By using benzothiol (BT) and pentafluorobenzothiol (PFBT) SAMs, the hole injection barrier between Au and the highest occupied molecular orbital (HOMO) of TES ADT was controlled. After a solvent annealing, TES ADT OTFTs with PFBT SAM-treated Au electrodes were found to exhibit high field-effect mobilities of $0.05\;cm^2/Vs$ and on/off current ratios of $10^6$.

• Journal of Sensor Science and Technology
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• v.19 no.6
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• pp.456-461
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• 2010

The detection of C-reactive protein(CRP) using self-assembled monolayer(SAM) was investigated by a portable surface plasmon resonance(SPR) sensor system. The CRP is a biomarker for the possible cardiovascular disease. The SAM was formed on gold(Au) surface to anchor the monoclonal antibody of CRP(anti-CRP) for detection of CRP. Sequence injection of the anti-CRP and bovine serum albumin(BSA) into the sensor system has been carried out immobilize the antibody and to prevent non-specific binding. The portable SPR system has two flow channels: one for the sample measurements and the other for the reference. The output SPR signal was increased with the injection of the anti-CRP, BSA and CRP due to binding of the proteins on the sensor chip. The valid output SPR signals was linearly related to the critical range of the CRP concentration. The experimental results showed the feasibility of the portable SPR system with newly developed SAM to diagnose a risk of the future cardiovascular events.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.569-574
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• 2014

Inverted bulk hetero-junction polymer solar cells (iPSC) composed of P3HT/PC61BM blends on the ZnO modified with benzoic acid derivatives-based self-assembled monolayers (SAM) are fabricated. Compared with the device using the pristine ZnO, the devices with ZnO surface modified SAMs derived from benzoic acid such as 4-(diphenylamino)benzoic acid (DPA-BA) and 4-(9H-carbazol-9-yl)benzoic acid (Cz-BA) as an electron transporting layer show improved the performances. It is mainly attributed to the favorable interface dipole at the interface between ZnO and the active layer, the eective passivation of the ZnO surface traps, decrease of the work function and facilitating transport of electron from PCBM to ITO electrode. The power conversion eciency (PCE) of iPSCs based on DPA-BA and Cz-BA treated ZnO reaches 2.78 and 2.88%, respectively, while the PCE of the device based on untreated ZnO is 2.49%. The open circuit voltage values ($V_{oc}$) of the devices with bare ZnO and SAM treated ZnO are not much different. Whereas, higher the fill factor (FF) and lower the series resistance ($R_s$) are obtained in the devices with SAMs modification.

• Journal of Ceramic Processing Research
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• v.23 no.3
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• pp.320-325
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• 2022

In this study, we investigated the deposition of trimethoxy(propyl)silane as a self-assembled monolayer (SAM) on the surface of an indium tin oxide (ITO) substrate in organic light-emitting diodes (OLEDs) by examining the changes in surface characteristics of the modified substrate with variations in deposition time and temperature. The highest contact angle was obtained at 160 ℃, and for each deposition time, the contact angles were 63°, 66°, 80°, 96°, 103°, 103°, 103°, and 104°, respectively, indicating the contact angle, and thus the hydrophobicity, increased with increasing deposition time and temperature. In addition, after 90 min of deposition, adequate SAM coverage was achieved on the ITO surface. When the coverage ratio was calculated, ≥ 99% coverage was obtained after 90 min of deposition at 160 ℃. Atomic force microscopy of samples with SAM coverage obtained after 90 min at different deposition tem-peratures revealed improvement in the surface roughness of the fabricated samples. The work function, measured using a photoelectron spectrometer, demonstrated a characteristic increase with increasing temperature. Thus, SAM deposition can improve the ITO surface properties depending on the time and temperature of deposition.

• 전자공학회논문지 IE
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• v.43 no.1
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• pp.1-4
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• 2006

The characteristics of polymeric thin-film transistors(TFTs) can be controlled by chemically modifying the surface of the gate dielectric prior to the organic semiconductor. The chemical treatment consists of derivative the tantalum pentoxide($Ta_2O_5$) surface with organic materials to form self-assembled monolayer(SAM). The deposition of an octadecyl-trichlorosilane(OTS), hexamethy-ldisilazone(HMDS), aminopropyltreithoxysilane(ATS) SAM leads to a mobility of $0.01\sim0.06cm2/V{\cdot}s$ in a poly-3-hexylthiophene(P3HT) conjugated polymer. The mobility enhancement mechanism is likely to involve molecular interactions between the polymer and SAM. These result can be used for polymer TFT's dielectric material.