Electrochemical characterization of self-assembled ferrocene-terminated alkanethiol monolayers on low-index gold single crystal electrodes

• Published in: Electrochimica acta 2013-01, Vol.87, p.770-778
• Main Authors: Rudnev, Alexander V., Yoshida, Koji, Wandlowski, Thomas
• Format: Article
• Language: English
• Subjects: Alkanethiol; Crystal defects; Cyclic voltammetry; Density; Electrodes; Ferrocene; Gold; Gold single crystal; Monolayers; Scanning tunneling microscopy; Self-assembled monolayer; Single crystals; Terminals
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2012.09.090

[Display omitted] ► Disordered FcC11 regions coexist with locally ordered patches on Au(hkl). ► The substrate surface structure effects strongly the properties of FcC11 SAMs. ► 2D-ordered ion-paired patches display net attractive lateral interactions. We present a voltammetric and in situ STM study of 11-ferrocenyl-1-undecanethiol (FcC11) assembled on low-index single crystal and polycrystalline gold electrodes. The influence of electrode surface structure as well as of structure defects in the self-assembled FcC11 monolayers on the electrochemical response during the oxidation and reduction of the terminal ferrocene group is explored. The nature of the redox peaks is discussed in detail. We identified the coexistence of disordered FcC11 regions with 2D patches of “locally ordered” FcC11 species. We demonstrate that close-packed domains are preferentially formed at atomically flat terraces. Increasing the defect density of the substrate surface leads to a decreasing amount of locally ordered FcC11 molecules.