Electrochemical Scanning Tunneling Microscopy:  Adlayer Structure and Reaction at Solid/liquid Interface

Abstract

The adlayer structure and reaction at the solid/liquid interface has been intensively investigated due to its importance in many physical chemistry and life processes. The emergence of electrochemical scanning tunneling microscopy (ECSTM) provides a new opportunity to study this subject at the atomic and molecular level in aqueous solution. This feature article summarizes some of the latest progress in ECSTM application for the understanding of the structure and reactions taking place at the solid/liquid interface. The adsorption of atoms and organic molecules is clearly revealed, and the knowledge of the underlying molecule/substrate and intermolecular reactions governing the adlayer formation on the surface is deduced. In addition, the effect of external stimuli, such as electrode potential and UV light, on the adlayer structure is demonstrated. Finally, the prospects of future development in this exciting field are outlined.

Structural selection of graphene supramolecular assembly oriented by molecular conformation and alkyl chain

“…PAHs and their derivatives contain 2D subsections of graphene and show significant advantages, such as good solubility and ability to bear different chemical functionalities in their periphery with various electronic properties. These graphene molecules are promising candidates as building block for nanodevices through self-assembled architectures on 2D solid surfaces (9, 10).As a powerful tool for nanoscience and nanotechnology, scanning probe microscopy, in particular, scanning tunneling microscopy (STM) studies have produced images of the molecular self-assembly of graphene molecules at atomic/submolecular resolution, providing molecular understanding of intermolecular interactions and origin of their physical/chemical properties (11)(12)(13)(14). Because of their chemical structures, most of PAHs have a planar conformation and are inclined to form well-defined long-range self-assemblies on various substrates, such as gold and highly oriented pyrolytic graphite (HOPG).…”

“…As a powerful tool for nanoscience and nanotechnology, scanning probe microscopy, in particular, scanning tunneling microscopy (STM) studies have produced images of the molecular self-assembly of graphene molecules at atomic/submolecular resolution, providing molecular understanding of intermolecular interactions and origin of their physical/chemical properties (11)(12)(13)(14). Because of their chemical structures, most of PAHs have a planar conformation and are inclined to form well-defined long-range self-assemblies on various substrates, such as gold and highly oriented pyrolytic graphite (HOPG).…”

Structure transitions between copper-sulphate and copper-chloride UPD phases on Au(111)

“…[1][2][3][4][5][6][7][8] One particularly attractive class of systems represent metal adlayers prepared by underpotential deposition (UPD). This process refers to the electrodeposition of metal monolayers on a foreign metal substrate at potentials more positive than the bulk equilibrium potential on the same metal.…”

Zusammenrücken und Stapeln: von atmenden Poren zu dreidimensionaler ionischer Selbstorganisation unter elektrochemischer Kontrolle

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[4] PQPClO 4 ist ein Salz, weswegen eine starke Antwort der Ionen auf die Effekte des Grenzflächenpotentials [5] sowie auf die elektrostatischen Kräfte, welche die ionische Selbstorganisation bestimmen, erwartet wird.[6] Des Weiteren ist die aromatische Verbindung flach und neigt deshalb wegen ihrer p-Elektronen zu einer starken Wechselwirkung mit dem Goldsubstrat.[7] Da wir eine kompetitive Adsorption von Zielmolekül und Leitelektrolyten vermeiden wollten, wurden alle Experimente in Perchlorsäure durchgeführt, deren Anion nicht spezifisch auf Gold adsorbiert.Das Cyclovoltammogramm (siehe Hintergrundinformationen) einer modifizierten Au(111)-Elektrode in 0.1 m HClO 4 zeigte keine Peaks, was die Abwesenheit von Redoxprozessen und die lange Zeitskala der Phasentransformationen anzeigt, die dafür bekannt sind, beträchtliche Peaks

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“…Die ¾nderungen sind vollständig reversibel und kçnnen die Basis für elektrochemisch kontrollierte, dynamische Wirt-Gast-Systeme und dreidimensionale (3D-)Strukturen, wie künstliche Rezeptoren, bilden. [3] Unser Molekül, 9-Phenylbenzo [1,2]chinolizino [3,4,5,6fed]phenanthridinyliumperchlorat (Abbildung 1), in der Folge als PQPClO 4 bezeichnet, ist eine geladene, scheibenfçrmige, polycyclische, aromatische Verbindung, die im Festkçrper geschichtete Strukturen bildet. [4] PQPClO 4 ist ein Salz, weswegen eine starke Antwort der Ionen auf die Effekte des Grenzflächenpotentials [5] sowie auf die elektrostatischen Kräfte, welche die ionische Selbstorganisation bestimmen, erwartet wird.…”