• Title/Summary/Keyword: Viologen

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Electrochemical Properties of Self-Assembled Viologen Monolayers Using Quartz Crystal Analyzer (QCA를 이용한 자기조립된 Viologen 단분자막의 전기화학적 특성)

  • Lee, Dong-Yun;Park, Sang-Hyun;Shin, Hoon-Kyu;Park, Jae-Chul;Chang, Jeong-Soo;Kwon, Young-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.04b
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    • pp.141-144
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    • 2004
  • Molecular self-assembled of surfactant viologens are recently interesting because they can be from functional electrodes as well as micelle assemblies which can be profitably utilized for display devices, electrochemical studies and electrocatalysis as electron acceptor or electron mediator. The electrochemical behavior of self-assembled viologen monolayer on Au electrode surface has been investigated with QCM which has been known as nano-gram order mass detector. A monolayer of viologen is immobilized on the gold electrode surface and the normal potentials corresponding to the to the successive one-electron transfer processes of the viologen actives are two peaks in 0.1mol/l phosphate buffer solution respectively. These result suggest that the viologen SAMs are stable and well-behaved monolayers.

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Electrochemical Properties of Viologen Self-Assembly Monolayer Using QCM (수정진동자를 이용한 Viologen Self-Assembly 단분자막의 전기화학적 특성)

  • Ock, J.Y.;Song, S.H.;Shin, H.K.;Park, J.C.;Chang, J.S.;Chang, S.M.;Kwon, Y.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.11a
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    • pp.403-406
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    • 2002
  • Molecular self-assembled of surfactant viologen are of recent interest because they can from functional electroeds as well as micellar assemblies. which can be profitably utilized for display devices. photoelectrochemical studies and electrocatalysis as electron acceptor or electron mediator[1-3]. Fromherz et al studied the se1f-assembly of thiol and disulfide derivatives of viologens bearing long n-alkyl chains on Au electrode surface[4]. In this study, the electrochemical behavior of self-assembled viologen monolayer has been investigated with QCM, which has been known as nano-gram order mass detector. The self-assembly process of viologen was monitored using resonant frequency$({\Delta}F)$ and resonant resistance(R). The redox process of viologen was observed with resonant frequency$({\Delta}F)$.

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Study on barrier characteristics of STM tip/Viologen molecules and morphology (STM tip/Viologen 분자의 Barrier특성과 모폴로지 촉정)

  • Lee, Nam-Suk;Choi, Won-Suk;Qian, Dong-Jin;Kwon, Young-Soo
    • Proceedings of the KIEE Conference
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    • 2006.10a
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    • pp.91-92
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    • 2006
  • The electrical properties of viologen derivatives were studied in terms of the tunneling current characteristics on the length of the viologen derivatives using self-assembling techniques and ultra high vacuum scanning tunneling microscopy (UHV-STM). We fabricated the Au substrate were deposited by thermal evaporation system ($420^{\circ}C$. Self-assembled monolayers (SAMs) were prepared on Au (111), which had been thermally deposited onto freshly cleaved, heated mica. The Au substrate was exposed to a 1 mM solution of viologen derivatives in ethanol for 24 hours to form a monolayer. We measurement of the morphology on the single viologen molecules ($VC_{8}SH$, $VC_{10}SH$, $HSC_{8}VC_{8}SH$, and $HSC_{10}VC_{10}SH$). The current-voltage (I-V) and differential conductance (dl/dV-V) properties were measured while the electrical properties of the formed monolayer were scanned by using a STS. The effective barrier height of viologen derivatives ($VC_{8}SH$, $VC_{10}SH$, $HSC_{8}VC_{8}SH$, and $HSC_{10}VC_{10}SH$) were calculated to be 1.076 eV, 1.56 ${\pm}$ 0.3 eV, 1.85 eV, 2.28 eV, respectively.

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Determining the Self-Assembly and Redox Process of a Viologen Monolayer by Electrochemical Quartz Crystal Microbalance (수정진동자를 이용한 Viologen 단분자막의 자기조립화와 산화,환원 반응 측정)

  • Ock, J.Y.;Song, S.H.;Shin, H.K.;Chang, J.S.;Chang, S.M.;Kwon, Y.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.05c
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    • pp.23-27
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    • 2003
  • Molecular self-assembled of surfactant viologen are of recent interest because they can from functional electrodes as well as micellar assemblies, which can be profitably utilized for display devices, photoelectrochemical studies and electrocatalysis as electron acceptor or electron mediator. Fromherz et al studied the self-assembly of thiol and disulfide derivatives of viologens bearing long n-alkyl chains on Au electrode surface. The electrochemical behavior of self-assembled viologen monolayer has been investigated with QCM, which has been known as nano-gram order mass detector. The self-assembly process of viologen was monitored using resonant frequency$({\Delta}F)$ and resonant resistance(R). The redox process of viologen was observed with resonant frequency $({\Delta}F)$.

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Study on Electrochemical Sensing Property of Harbor Pollutants using Viologen Derivative (Viologen 유도체를 이용한 항만오염물질의 전기화학적 센싱 특성 연구)

  • Park, Sang-Hyun;Lee, Dong-Yun;Kwon, Young-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.04c
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    • pp.119-120
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    • 2008
  • In this paper, viologen derivative is used as charge transfer material to develop sensors for detecting the organic pollutants which are the main reason of harbor pollution. We fabricated self-assembled monolayers of viologen derivative on gold electrode of QCM and investigated an electrochemical behavior property. We also determined electrochemical sensing property about environmental pollution materials such as bezene, phosphate and surfactant through quantitative and qualitative analysis of charge transfer using intrinsic property of viologen derivative by temperature and concentration change. From the achieved results, we can apply and develope the detecting sensors for harbor pollutants.

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Study on Charge Transfer Characteristics of Self-Assembled Viologen Monolayers

  • Park Sang-Hyun;Lee Dong-Yun;Kwon Young-Soo
    • KIEE International Transactions on Electrophysics and Applications
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    • v.5C no.4
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    • pp.161-164
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    • 2005
  • Viologen has been extensively investigated in the paper because their well-behaved electrochemistry has led to their use in a variety of theses, including the electron acceptor for the electric charge delivery mediation of the devices. It was formed monolayer in QCM by self-assembly method. We could know the adsorbed mass of viologen molecules from the frequency shift. We calculated that the adsorbed mass was about 196 [$ng/cm^2$]. We studied the electron transfer property of viologen by the cyclic voltammetry among the electrochemical process so we changed an anion like 0.1 M $NaClO_4$ and $Na_3PO_4$ electrolyte solution and investigated the interrelationship between scan rate and peak current when scan rates were increased twice.

Study on Morphology Investigation and Electron-Transfer Property of Self-Assembled Viologen Monolayers (자기조립된 Viologen 단분자막의 모폴로지 관찰과 전하이동 특성 연구)

  • Lee, Dong-Yun;Park, Sang-Hyun;Kwon, Young-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.395-396
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    • 2005
  • We fabricated self-assembled monolayers(SAMs) onto quartz crystal microbalance(QCM) using viologen, which has been widely used as electron acceptor and electron transfer mediator. We determined the time dependence to resonant frequency shift during self-assembly process and observed the morphology of self-assembled mono layers by STM and investigated the electrochemical behavior of SAMs by cyclic voltammetry. Electrochemical deposition of viologen was investigated using electrochemical quartz crystal microbalance(EQCM). The redox reactions of viologen were highly reversible and the EQCM has been employed to monitor the electrochemically induced adsorption of SAMs during the redox reactions.

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Study on the Electrochemical Behavior of the Viologen Monolayers by Different Chemical Structure (분자구조에 따른 Viologen 단분자막의 전기화학적 특성 연구)

  • Ock, Jin-Young;Shin, Hoon-Kyu;Chang, Jeong-Soo;Kwon, Young-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.918-921
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    • 2003
  • The electrochemical behavior of vilogen self-assembled monolayer has been investigated with QCM, which has been known as ng order mass detector. The self-assembly process of viologen was monitored using resonant frequency(${\Delta}F$) and resonant resistance(R). The QCM measurements indicated a mass adsorption for viologen assembling on the gold surface with a frequency change about 300, 135 Hz and calculated its surface coverage($\Gamma$) to be $5.02{\times}10^{-9}$ and $1.64{\times}10^{-9}mol/cm^2$. Also a reversible redox process was observed and analyzed with an ionic interaction at the Viologen/solution interface using ${\Delta}F$.

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Surface Charge Transfer of Self-Assembled Viologen Derivative Using Quartz Crystal Microbalance (수정진동자를 이용한 자기조립된 Viologen 유도체의 계면전하이동 특성)

  • Park, Sang-Hyun;Ryu, Kil-Yong;Lee, Dong-Yun;Kwon, Young-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.256-257
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    • 2005
  • We fabricated self-assembled monolayers(SAMs) onto quartz crystal microbalance(QCM) using viologen, which has been widely used as electron acceptor and electron transfer mediator. The viologen derivative exist in three redox states, namely. These redox reactions are highly reversible and can be cycled many times without significant side reactions, respectively. We studied the characteristics of charge transfer using different electrolyte solutions by electrochemical quartz crystal microbalance (EQCM). From the data, the redox peak currents were nearly equal charges during redox reaction and existed to an excellent linear interrelation between the scan rates and first redox peak currents. The redox reactions of viologen were highly reversible and the EQCM has been employed to monitor the electrochemically induced adsorption of SAMs during the redox reactions.

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