Self‐Assembled Monolayers on Electrodes

Abstract

Alkanethiols and related molecules spontaneously adsorb from solution or vapor phase onto oxide‐free metals, especially gold, to form close‐packed oriented monolayers. The ease and flexibility of the self‐assembly process provides a convenient method for altering the properties of the metal as an electrode. The close‐packed hydrocarbon layer blocks access of most solution species to the electrode surface. Consequently, interfacial capacitances are markedly reduced and most electron‐transfer reactions are strongly inhibited. The monolayers also provide a foundation for attachment of additional molecules or molecular layers to electrodes. Self‐assembled monolayers (SAMs) on electrodes have been used in voltammetric methods to improve the analytical sensitivity and to impart greater selectivity towards specific analytes. Redox molecules have been anchored at fixed and controllable distances from the electrode surface, thereby permitting the study of electron‐transfer kinetics over long distances and at large driving forces. The ability of SAMs to inhibit metal corrosion and to promote better adhesion of electroactive polymers has been demonstrated.

Insights into the surface and redox properties of single-walled carbon nanotube—cobalt(II) tetra-aminophthalocyanine self-assembled on gold electrode

“…This electrochemical pre-treatment serves to further remove any physically adsorbed species on the surface of the modified electrodes not removed by the rinsing process described in the experimental and, most importantly, to give an insight into the electrochemical stability of these electrodes which is crucial to their studies and application in aqueous solutions. , [22], [23], [24], [25] and [26]. The modification of the Au with any of the species resulted in increased capacitive charging current of the bare gold electrode.…”

“…To minimize possible experimental errors from the use of different gold electrodes, one electrode was used for all experiments reported in this work. The roughness factor of this gold electrode was first determined, after thorough cleaning as described above, by the conventional methodology [25] and [26] using the RandlesSevčik equation:…”

“…Self-assembly may simply be described as a spontaneous, coordinated chemical reaction of individual molecular building blocks (especially alkanethiols and thiol-derivatised organomolecules) to create stable, well-organized arrays of ultrathin superstructure films on coinage metals, notably gold [21], [22], [23], [24], [25] and [26]. The formation of self-assembled monolayers (SAMs) of organomolecules on gold surfaces has continued to attract considerable research interests due to their crucial importance in biology, chemistry and supramolecular nanotechnology.…”

“…The formation of self-assembled monolayers (SAMs) of organomolecules on gold surfaces has continued to attract considerable research interests due to their crucial importance in biology, chemistry and supramolecular nanotechnology. SAMs have been known to offer convenient model systems for probing the interfacial electron-transfer processes [24], [25], [26] and [27], and have been extensively studied in corrosion protection [24], [25], [26], [28] and [29], fabrication of electrochemical-and bio-sensors [15], [17], [18], [19], [20], [30], [31], [32] and [33] and molecular electronic devices [34] and [35].…”

Non-destructive characterization of CoTSPc electrochemically deposited on gold electrodes by means of synchrotron X-ray microfluorescence

“…Various techniques have been used to create modified electrodes, including drop drying, spin coating and spontaneous adsorption (self-assembling) [9][10][11]. In comparison with these techniques, electrodeposition is a technique that enables one to control and to characterize the formed layer by following the potential and current during the process.…”