Potential- and concentration-dependent self-assembly structures at solid/liquid interfaces

Nanoscale ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 3438-3443 ◽  
Author(s):  
Zhen-Feng Cai ◽  
Hui-Juan Yan ◽  
Dong Wang ◽  
Li-Jun Wan
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Self Assembly ◽  
Scanning Tunneling ◽  
Liquid Interfaces ◽  
Tunneling Microscopy ◽  
Controlled Assembly ◽  
Electrochemical Scanning Tunneling Microscopy ◽  
Solid Liquid

We report the potential and concentration controlled assembly of an alkyl-substituted benzo[1,2-b:4,5-b′]dithiophene (DDBDT) on an Au(111) electrode byin situelectrochemical scanning tunneling microscopy (ECSTM).

scholarly journals Potential Driven Non-Reactive Phase Transitions of Ordered Porphyrin Molecules on Iodine-Modified Au(100): An Electrochemical Scanning Tunneling Microscopy (EC-STM) Study

Surfaces ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 12-28 ◽  
Author(s):  
Tomasz Kosmala ◽  
Matías Blanco ◽  
Gaetano Granozzi ◽  
Klaus Wandelt
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Long Range ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
The Self ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Electrode Potentials ◽  
Electrochemical Scanning Tunneling Microscopy

The modelling of long-range ordered nanostructures is still a major issue for the scientific community. In this work, the self-assembly of redox-active tetra(N-methyl-4-pyridyl)-porphyrin cations (H2TMPyP) on an iodine-modified Au(100) electrode surface has been studied by means of Cyclic Voltammetry (CV) and in-situ Electrochemical Scanning Tunneling Microscopy (EC-STM) with submolecular resolution. While the CV measurements enable conclusions about the charge state of the organic species, in particular, the potentio-dynamic in situ STM results provide new insights into the self-assembly phenomena at the solid-liquid interface. In this work, we concentrate on the regime of positive electrode potentials in which the adsorbed molecules are not reduced yet. In this potential regime, the spontaneous adsorption of the H2TMPyP molecules on the anion precovered surface yields the formation of up to five different potential-dependent long-range ordered porphyrin phases. Potentio-dynamic STM measurements, as a function of the applied electrode potential, show that the existing ordered phases are the result of a combination of van der Waals and electrostatic interactions.

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