Formation of 1,8-Octanedithiol Mono- and Bilayers under Electrochemical Control

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• 作者：Daniel Garca-Raya ; Rafael Madueo ; Manuel Blzquez ; Teresa Pineda
• 刊名：Journal of Physical Chemistry C
• 出版年：2010
• 出版时间：March 4, 2010
• 年：2010
• 卷：114
• 期：8
• 页码：3568-3574
• 全文大小：248K
• 年卷期：v.114,no.8(March 4, 2010)
• ISSN：1932-7455

文摘

We present results of the formation of 1,8-octanedithiol (ODT) monolayers on the Au(111) single-crystal surfaces by oxidative deposition from alkaline solutions under electrochemical control. Cyclic voltammetry shows the presence of two well-separated oxidative peaks that are assigned to the formation of the S−Au bond (peak A1) and the oxidation of the thiolate species to give the disulfide dimer either in solution or in the adsorbed state (peak A2). The formation of a disulfide species can take place with the participation of two neighboring ODT molecules or through the formation of a bilayer in the adsorbed state. The reductive desorption of the layers formed under these conditions gives us some information about its nature and allows us the choice of the experimental conditions to carry out a potentiostatic method to build the layers of ODT with determined properties. Electrochemical techniques, such as cyclic voltammetry, differential capacitance−potential, and chronocoulometry curves, are used to discriminate between the monolayer and bilayer formation. Moreover, XPS data are used to confirm the electrochemical results. It is concluded that very reproducible layers that contain mainly standing-up ODT molecules are formed by the potentiostatic method and that they are built in a shorter time than those formed by the spontaneous assembly from an ethanolic solution.