Understanding the effect of external parameters, e.g., pH and electrochemical potential, on the ordering of two-dimensional architectures is important and has many potential applications in molecule-based devices, nanoelectronics and biosensors. In this study, triaminobenzene (TAB) and terephthalic acid (TPA) were chosen to explore the role of pH-induced hydrogen-bonding in the formation of two-dimensional nanostructures in acidic, neutral and basic solutions under potential control on Au(111). TPA forms long range ordered supramolecular adlayer in sulfuric acid and moderately acidic solution (pH ~ 5.5), presumably driven by hydrogen bonding.  However, no ordered pattern of TAB was detected in sulfuric acid in contrast to TPA.  At pH ~ 5.5, TAB forms different ordered domains on negatively charged Au(111).  In addition, we address the formation of a hybrid structure of TPA with TAB and the interaction among molecules having different functional groups to build up pH-induced ordered domains.

Fabrication of 2D supramolecular structures via pH-induced hydrogen bonding: An electrochemical scanning tunneling microscopy study

244th National Meeting (2012)

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