The electrochemical characterisation of benzyl mercaptan-modified Au(111): Structure and copper deposition

Abstract

The behaviour of benzyl mercaptan self-assembled monolayers on Au(111) in sulfuric acid solution was studied using cyclic voltammetry and in situ scanning tunnelling microscopy. Modification of the Au(111) surface in an ethanolic solution of benzyl mercaptan leads to a disordered monolayer. However, by partial reductive desorption a striped c (15 x sqrt [3]) and a (2 x sqrt [3]) structure were obtained. The disordered benzyl mercaptan film was also used for the study of copper deposition. At -0.02 V versus SCE, that is in the underpotential deposition region, monoatomic high islands appear on the surface. Bulk deposition of copper starts at -0.08 V versus SCE with the growth of dendrites underneath the thiol film. At higher overpotentials, the growth of three-dimensional copper clusters commences.

Self-assembled monolayers of benzenethiol and benzenemethanethiol on Au(111): Influence of an alkyl spacer on the structure and thermal desorption behavior

“…In particular, self-assembled monolayers (SAMs) prepared by the spontaneous adsorption of organic thiols onto gold are considered a promising molecular system for many technological applications due to their ease of preparation, high structural order and stability, and easy modification of surface properties using thiol molecules with a functional terminal group [1][2][3][4][5]. Recently, aromatic thiol SAMs on gold have become more important and have yielded interesting molecular systems, due to their electric conductivity and optical properties, which can be applicable to molecular electronics [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. To obtain reliable device performance, a precise structural control of SAMs down to molecular-scale dimensions is required since the properties of SAMs are strongly influenced by their structure, such as twodimensional (2D) packing arrangements, molecular density, tilt angle of the phenyl backbone, and interface adsorption structure.…”

Temperature-induced phase transition; Polymorphism in BP2 SAMs on Au(111)

“…However, these structures are not the only structures observed for aromatic thiols on Au(111). For example, a striped (7×√3) phase for 2-phenylmercaptan [33] and striped (15×√3) and (2×√3) structures for benzylmercaptan [34] were recently observed on Au(111). Recently the SAMs formed from ω-(4΄-methylbiphenyl-4-yl)ethanethiol (CH 3 (C 6 H 4 ) 2 (CH 2 ) 2 SH), BP2 have been studied [44].…”

Correspondence between Experiment and Theory of Bulk Electrocrystallisation at Solid Electrodes in Aqueous Electrolyte

“…In experiments of CV, chronoamperometry and polarography, redox processes are identified by specific peak positions in current density (2)(3)(4)(5)(6)(7)(8)(9). Well-defined peaks in current density are obtained in systems where metallic ions are reduced at metallic surfaces more noble than the metals of the electrolyte.…”

“…These same vents for hydrogen liberation also account for electrocrystallisation that proceed by growth of dendrites , 16 (46) 25-35 (2009) underneath the SAM (6), where the dendrites growth occurs at the sites of high-density hydrogen. Once the dendrites grow in the direction perpendicular to the surface, the hydrogen evolves also from the surface of the dendrites thus forming characteristic 'mushroom-shaped' structures (7). Accordingly, it is predicted that the density of imperfections in the SAM structure never vanishes under electrochemical conditions, unless hydrogen follow some other pathways different from through-layer movement to the diffusion layer.…”