• 대한기계학회논문집A
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• 제32권6호
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• pp.459-464
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• 2008

We present a novel microcantilever device with nano-interdigitated electrodes (nano-IDEs) and DNA selective immobilization on the nano-IDEs for biosensing applications. Using the nano-IDEs and cyclic voltammetric methods, we have achieved selective immobilization of DNA with submicrometer spatial resolution on a freestanding microcantilever. $70{\sim}500\;nm$-wide gold (Au) nano-IDEs are fabricated on a low-stress SiNx microcantilever with dimensions of $100{\sim}600\;{\mu}m$ in length, and $15{\sim}60\;{\mu}m$ in width, with a $0.5\;{\mu}m$ thickness using electron beam lithography and bulk micromachining. Streptavidin is selectively deposited on one side of the nano-IDEs using cyclic voltammetry at a scan rate of 0.1 V/s with a range of $-0.2{\sim}0.7\;V$ during $1{\sim}5$ cycles. The selective deposition of dsDNA is confirmed by fluorescence microscopy after labeling with YOYO-1 dye.

• 한국응용과학기술학회지
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• 제27권2호
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• pp.202-207
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• 2010

We investigated the electrochemical properties for Langmuir-Blodgett(LB) films mixed with l-bromotetradecane(Cl4), l-bromohexadecane(Cl6), and l-bromooctadecane(Cl8). The alkyl bromides mixture was deposited by using the Langmuir-Blodgett method on the ITO glass. The electrochemical properties measured by using cyclic voltammetry with a three-electrode system(an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode) at various concentrations(0.5, 1.0, 1.5 and 2.0 N) of $NaClO_4$ solution. A measuring range was reduced from initial potential to -1350 m V, continuously oxidized to 1650 mV. The scan rate was 100 mV/s. As a result, LB films of Cl4, Cl6, and Cl8 mixture monolayers appeared irreversible process caused by only the oxidation current from the cyclic voltammogram. The diffusivity(D) effect of LB films decreased with increasing of alkyl bromides amount.

• 분석과학
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• 제12권3호
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• pp.184-189
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• 1999

수용액에서 vanadate와 N-benzyliminodiacetate (Bz-IDA) 리간드의 상호작용을 $^{51}V$ 핵자기공명분광법과 순환전압-전류법을 이용하여 조사하였다. $^{51}V$ 핵자기공명분광법 결과 바나듐(V)-Bz-IDA착물생성에 의한 두 개의 특정 피크(-515.5 ppm 및 -500.1 ppm)를 관찰할 수 있었다. 순환전압-전류법을 이용하여 얻어진 결과 바나듐(V)-Bz-IDA착물의 산화-환원파의 전위값은 각각 -0.05 V 및 -0.13 V에서 관찰하였다. 이로써 산화-환원반응은 가역적 일전자반응으로 추정되었다.

• 전기화학회지
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• 제2권1호
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• pp.38-45
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• 1999

Electrochemical lithium intercalation into a PECVD (plasma enhanced chemical vapour deposited) carbon film electrode was investigated in 1 M $LiPF_6-EC$ (ethylene carbonate) and DEC (diethyl carbonate) solution during lithium intercalation and deintercalation, by using cyclic voltammetry supplemented with ac-impedance spectroscopy. The size of the graphitic crystallite in the a- and c-axis directions obtained from the carbon film electrode was much smaller than those of the graphite one, indicating less-developed crystalline structure with hydrogen bonded to carbon, from the results of AES (Auger electron spectroscopy), powder XRD (X-ray diffraction) method, and FTIR(Fourier transform infra-red) spectroscopy. It was shown from the cyclic voltammograms and ac-impedance spectra of carbon film electrode that a threshold overpotential was needed to overcome an activation barrier to entrance of lithium into the carbon film electrode, such as the poor crystalline structure of the carbon film electrode showing disordered carbon and the presence of residual hydrogen in its structure. The experimental results were discussed in terms of the effect of host carbon structure on the lithium intercalation capability.

• 한국전기전자재료학회논문지
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• 제19권8호
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• pp.724-731
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• 2006

We investigated the electrochemical properties for Langmuir-Blodgett (LB) films mixed with 4-octyl-4'-(5-carboxylpentamethyleneoxy)azobenzene (denoted as 8A5H) and phospholipid(L-a-dimyristoylphosphatidylcholine, denoted as DMPC and L-a-dilauroylphosphayidylcholine, denoted as DLPC). The LB films of 8A5H, 8A5H-DMPC and 8A5H-DLPC mixture monolayers were deposited by using the LB method on the indium tin oxide(ITO) glass. The electrochemical properties measured by using cyclic voltammetry with a three-electrode system, an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode at various concentrations(0.1, 0.5, and 1.0 mol/L) of $NaClO_4$ solution. A measuring range was reduced from initial potential to -1350 mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rates were 50, 100, 150 and 200 mV/s, respectively. As a result, LB films of 8A5H and 8A5H-DLPC mixture monolayers appeared irreversible process caused by only the oxidation current from the cyclic voltammogram and LB films of 8A5H-DMPC monolayer mixture was found to be caused by a reversible oxidation-reduction process.

• Bulletin of the Korean Chemical Society
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• 제28권8호
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• pp.1322-1328
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• 2007

The catalytic activity of poly[(2,2'-bipyridine)copper(II)-μ4-oxalato] coated on a glassy carbon electrode (GCE) for O2 electroreduction is examined using cyclic voltammetry and rotating disk electrode techniques. The cyclic voltammograms show that O2 is electroreduced on pBpCuOx-coated GCE surfaces at a peak potential of ? 0.25 V in pH 4.7 acetate buffer media. The electroreduction of O2 on pBpCuOx-coated GCE occurs at 450 mV more positive potential than that found at a bare GCE. The catalytic activity originates from Cu(II) coordinated by bipyridine in the complexes and the polymer type Cu-complex films exhibit an enhanced stability compared to monomeric Cu-complexes during the O2 electroreduction. The rotating disk electrode measurements reveal that the electroreduction of O2 on pBpCuOx-coated GCE is a four-electron process. Kinetic parameters for O2 reduction on pBpCuOx-coated GCE are obtained from rotating disk experiments and compared with those on bare glassy carbon electrode surfaces.

• 한국응용과학기술학회지
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• 제20권2호
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• pp.125-129
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• 2003

The effects of molecular structure on the redox properties of the organic electroluminescent materials (Ir$(ppy)_3$ Ir$(m-ppy)_3$ Ir$(p-toly)_3$) were studied using cyclic voltammetry and spectroscopy. These iridium complexes show reversible oxidation and reduction on the electrode, which produce the symmetric cyclic voltammogram. It indicates that these materials are very stable under repetitive oxidation/reduction cycles. The electrochemically determined ionization potentia/electron affinity values are 5.4OeV/3.02eV for Ir$(ppy)_3$, 5.36eV/2.96eV for Ir$(m-ppy)_3$, and 5.35eV/2.97eV for Ir$(p-toly)_3$ from the SCE(Standard Calomel Electrode). The electrically determined band gaps are 2.38eV (521nm), Ir$(ppy)_3$, 2.4OeV (517nm), Ir$(m-ppy)_3$, and 2.38eV (521nm). Ir$(p-toly)_3$, which are similar with the optical band gaps. The position of methyl group on 2-phenylpyridine (ppy) effects do not influence much on the ionization potential, electron affinity, and band gap of Ir$(ppy)_3$ derivatives.

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1462-1466
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• 2013

We demonstrate that ruthenium oxide ($RuO_2$) nanotubes with controlled dimensions can be synthesized using facile electrochemical means and anodic aluminum oxide (AAO) templates. $RuO_2$ nanotubes were formed using a cyclic voltammetric deposition technique and an aqueous plating solution composed of $RuCl_3$. Linear sweep voltammetry (LSV) was used to determine the effective electrochemical oxidation potential of $Ru^{3+}$ to $RuO_2$. The length and wall thickness of $RuO_2$ nanotubes can be adjusted by varying the range and cycles of the electrochemical cyclic voltammetric potentials. Thick-walled $RuO_2$ nanotubes were obtained using a wide electrochemical potential range (-0.2~1 V). In contrast, an electrochemical deposition potential range from 0.8 to 1 V produced thin-walled and longer $RuO_2$ nanotubes in an identical number of cycles. The dependence of wall thickness and length of $RuO_2$ nanotubes on the range of cyclic voltammetric electrochemical potentials was attributed to the distinct ionic diffusion times. This significantly improves the ratio of surface area to mass of materials synthesized using AAO templates. Furthermore, this study is directive to the controlled synthesis of other metal oxide nanotubes using a similar strategy.

• 전기화학회지
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• 제2권4호
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• pp.209-212
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• 1999

H-형의 분리 셀을 사용하여 중성 및 실온의 온화한 조건에서 조절 전위법 음전극 반응에 의한 nitroarene화합물들의 환원 짝지음 반응으로 높은 수율의 azobenzene유도체를 합성하였다. Pb또는 Pt cathode와 Pt anode를 사용하여 메탄을 용액 하에서 cyclic voltammetry에 근거하여 각 반응의 최적의 반응 조건을 결정한 후 반응을 실행하였으며, 대부분의 경우 환원 짝지음 반응은 치환기의 성질과 위치에 영향을 받지 않고 높은 수율로 성공적인 결과를 얻을 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.545-549
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• 2001

We have produced electrolyte solution out of 1.15M $LiPF_6$ EC/EMC/DEC/PC(30/55/10/5 by vol%) as a reference, and at the same time, performed basic physical property test using a single solvent of 1.15M $LiPF_6$ DEC, DMC, EMC and a 2 component electrolyte solution of 1.15M $LiPF_6$ EC/DEC(1/2 by vol%) and PC/DEC(1/2 by vol%). Cyclic Voltammetry Analysis showed that, compared to existing carbonate organic solvent, the addition of DEC,DMC and EMC brought the de-decomposition peak of salt anion of $PF_6$ and the solvent at lower oxidization potential of 2.3V, 0.7V and 2.1V(vs. $Li/Li^+$). In addition, a kinetics current peak, in which intercalation of Lt is proceeded at 750mV, 450mV(vs. $Li/Li^+$), was confirmed. These findings suggest that the DEC solvent decomposition occurred at an electric potential lower than that of oxidization of existing carbonate organic solvent. Through the impedance analysis, we checked electric charge transfer resistance($R_{ct}$) according to the electric potential of $Li^+$ intercalation at 750mV(vs. $Li/Li^+$), which was the same as the resistance ($R_f$) and cyclic voltammetry of SEI film that was formed at Reference. By doing so, we found that the significant decrease of polarization resistance($R_p$) when Reference was played a part in the formation of compact SEI layer at the initial decomposition reaction.