In Situ Dynamic Monitoring of Electrochemical Oxidative Adsorption and Reductive Desorption Processes of a Self-Assembled Monolayer of Hexanethiol on a Au(111) Surface in KOH Ethanol Solution by Scanning Tunneling Microscopy
- 23 March 2005
- journal article
- Published by American Chemical Society (ACS) in Langmuir
- Vol. 21 (9), 4024-4033
- https://doi.org/10.1021/la050209w
Abstract
Electrochemical oxidative formation and reductive desorption processes of a self-assembled monolayer (SAM) of hexanethiol on a Au(111) surface in KOH ethanol solutions containing various concentrations of hexanethiol were investigated by in situ scanning tunneling microscopy in real time. The generation and disappearance of vacancy islands (VIs), corresponding to the formation and desorption of the SAM, respectively, were observed as anodic and cathodic current, respectively, flowed when the thiol concentration was higher than ca. 1 μM. When the VIs disappeared after the reductive desorption of the SAMs, the herringbone structure corresponding to the (√3 × 23) structure of Au(111), was observed on the surface, indicating that a clean reconstructed surface was exposed even in the hexanethiol ethanol solution. During both oxidative adsorption and reductive desorption of the SAMs, the shape of the steps of the gold substrate changed drastically and the step lines became parallel to the 〈121〉 direction of the Au(111) surface, suggesting that gold atoms on the surface were extremely mobile during these processes. The coalescence of adjacent vacancy islands and growth of larger islands triangular in shape accompanied with the disappearance of nearby smaller islands were observed, confirming that the VIs grew according to the Ostward ripening model.Keywords
This publication has 79 references indexed in Scilit:
- Reflection and Absorption Techniques for Optical Characterization of Chemically Assembled NanomaterialsAdvanced Materials, 2004
- Adsorption of self-assembling sulfur compounds through electrochemical reactions: Effects of potential, acid and oxidizing agentsPhysical Chemistry Chemical Physics, 2001
- Electrochemical Reactions in Adsorption of Organosulfur Molecules on Gold and Silver: Potential Dependent AdsorptionLangmuir, 2000
- In Situ Observation of the Two-Dimensional Crystals of Alkanes on a Reconstructed Au(100) Surface in Neat Liquid by Scanning Tunneling MicroscopyLangmuir, 2000
- Self-Assembly of n-Alkanethiol Monolayers. A Study by IR−Visible Sum Frequency Spectroscopy (SFG)The Journal of Physical Chemistry B, 1999
- Self-Assembly of n-Alkanethiols: A Kinetic Study by Second Harmonic GenerationThe Journal of Physical Chemistry B, 1999
- Very Efficient Visible-Light-Induced Uphill Electron Transfer at a Self-Assembled Monolayer with a Porphyrin−Ferrocene−Thiol Linked MoleculeJournal of the American Chemical Society, 1997
- Formation and Structure of Self-Assembled MonolayersChemical Reviews, 1996
- Synthesis, Structure, and Properties of Model Organic SurfacesAnnual Review of Physical Chemistry, 1992
- Atomic scale imaging of alkanethiolate monolayers at gold surfaces with atomic force microscopyJournal of the American Chemical Society, 1992