Electrochemical approaches and physical analysis to surface modification : nanoparticles, self-assembled monolayers, and surface behaviors표면 변형에 대한 전기화학적 접근법 및 물리적 해석 : 나노입자, 자기조립박막, 표면 거동

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The well-defined underpotential deposition systems consisting of Cu, Ag, Pb, and Tl on layered gold nanoparticle (AuNP) thin films linked with bifunctional 1,6-hexanedithiol (HDT) are described. Scanning electron microscopy informs the morphological structures of layered AuNPs accumulated by stepwise immersion in citrate-stabilized AuNP and HDT solutions. Although cyclic voltammograms for typical Au oxide formation show that colloidal AuNP frameworks are polycrystalline, (111) reflection is the major character in X-ray diffraction measurements. As the AuNP layers are piled up on indium tin oxide, faradaic currents for the underpotential deposition adsorption increase linearly, indicating that entire AuNPs are electrochemically accessible; as a result, the mass transport and the electron transfer are plausible in AuNP frameworks. Voltammetric profiles of Ag on AuNP and Cu on AuNP exhibit similar features with those on the bulk metal film. On the other hand, heavy metal systems of Pb/AuNP and Tl/AuNP reveal more enhanced adsorption currents and particularly irreversible cyclic voltammograms which explicate their strong binding properties to AuNPs by the small size of the hydrated metal ions. This electrochemical approach gives an alternative route to the construction of bimetallic clusters. The potential cycling, X-ray photoelectron spectroscopy and scanning electron microscopy demonstrate that the bimetallic cluster of Ag or Cu on AuNPs is a core-shelled shape, while the bimetallic cluster of Pb or Tl on AuNPs forms an alloyed structure. It is considered that characteristics of metal deposition on a bare substrate are largely dependent on concentration, composition of hydrated anions, and crystallinity of the substrate. However, they have been overlooked in the metal deposition to organic molecule-modified surfaces (especially, self-assembled monolayers), which is generalized as the degree of surface packing density and the chemical interaction between organic ...
Advisors
kwak, Ju-Hyounresearcher곽주현researcher
Description
한국과학기술원 : 화학과,
Publisher
한국과학기술원
Issue Date
2006
Identifier
258170/325007  / 020025236
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 2006.8, [ v, 94 p. ]

Keywords

surface electrochemistry; 표면 전기화학

URI
http://hdl.handle.net/10203/31675
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=258170&flag=dissertation
Appears in Collection
CH-Theses_Ph.D.(박사논문)
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