The effect of sulfur–metal bonding on the structure of self-assembled monolayers

Zharnikov, Michael; Frey, S.; Rong, H.; Yang, Yongjie; Heister, K.; Buck, Manfred; Grunze, M.

doi:10.1039/b004232n

Cited by 134 publications

(223 citation statements)

References 23 publications

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“…In fact, the main structural difference between thiol SAMs on the two metals appears to be that the first sulfur-carbon bond on the molecular side of the interface is slightly less inclined to the surface normal on Ag than it is on Au. [198][199][200][201][202]229,230] In terms of the interfacial electronic structure, the most relevant difference between silver and gold is the work function (F Au(111) $ 5.3 eV and F Ag(111) $ 4.7 eV). [231] In particular, Equations (8) suggest that changing the work function of the metal might impact the alignment of its Fermi level with the HOPS and LUPS in the SAM.…”

Section: Impact Of the Substrate Metalmentioning

confidence: 99%

Modeling the Electronic Properties of π‐Conjugated Self‐Assembled Monolayers

2010

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The modification of electrode surfaces by depositing self-assembled monolayers (SAMs) provides the possibility for controlled adjustment of various key parameters in organic and molecular electronic devices. Most important among them are the work function of the electrode and the relative alignment of its Fermi level with the conducting states in the SAM itself and with those in a subsequently deposited organic semiconductor. For the efficient application of such interface modifications it is crucial to reach a proper understanding of the relation between the chemical structure of a molecule, its molecular electronic characteristics, and the properties of the SAM formed by such molecules. Over the past years, quantum-mechanical calculations have proven to be a valuable tool for reaching a fundamental understanding of the relevant structure-property relations. Here, we provide a review over the field and report on recent progress in the modeling of the interfacial electronic properties of pi-conjugated SAMs. In addition to the insight that can be gained from simple electrostatic considerations, we focus on the quantum-mechanical description of the roles played by substituents, molecular backbones, chemical anchoring groups, and the packing density of molecules on the surface. Furthermore, we explicitly address the energy-level alignment at the interface between a prototypical organic semiconductor and a SAM-covered metal electrode and describe an approach suitable for extending the metallic character of the substrate onto the monolayer.

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Section: Impact Of the Substrate Metalmentioning

confidence: 99%

Modeling the Electronic Properties of π‐Conjugated Self‐Assembled Monolayers

2010

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“…Electron diffraction and STM measurements reveal that the monolayer forms a (√3 × √3) R30°overlayer structure on Au(111). Zarinkov et al demonstrated that hybridization and, thus, the spatial orientation of the bonding orbitals of sulfur is the determining factor for the orientation and density of the alkanethiol monolayer rather than the intramolecular interaction [22]. The T. PRADEEP AND N. SANDHYARANI surface order can extend over hundreds of square nanometers, and the symmetry of the sulfur atoms is hexagonal.…”

Section: Adsorption and Structure Of Samsmentioning

confidence: 99%

Structure and dynamics of monolayers on planar and cluster surfaces

Pradeep

Sandhyarani

2002

Pure and Applied Chemistry

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Organized molecular assemblies have been one of the intensely pursued areas of contemporary chemistry. Among the various methodologies used to make organized monolayer structures, self-assembled monolayers (SAMs) have been attractive to many materials chemists owing to the simplicity of the preparative method and high stability. Advances in various techniques and their application in the study of SAMs have significantly improved our understanding of these molecular systems. These studies have been further intensified since the successful preparation of stable metal clusters protected with monolayers. This article reviews the structure, temperature-induced phase transitions, and associated dynamics of monolayers, principally in the context of our own work in this area. Alkanethiols on Au (111) and Ag(111) are taken as archetypal systems to discuss the properties of 2D SAMs; studies from our laboratory have been on evaporated thin films. Alkanethiols on Au and Ag cluster surfaces are taken as examples of 3D SAMs. Although our principal focus will be on alkanethiols, we will touch upon a few other adsorbate systems as well.

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“…Electron diffraction and STM measurements reveal that the monolayers form a ð p 3 Â p 3Þ R308 overlayer structure, which is a balance between the S-Au chemisorption and the interaction between the chains. Zarnikov et al demonstrated that the hybridization and thus the spatial orientation of the bonding orbitals of sulphur is the determining factor for the orientation and density of the alkanethiol monolayer rather than the intramolecular interaction [107]. The surface order can extend over hundreds of square nanometres and the symmetry of the sulphur atoms is hexagonal.…”

Section: Structure Of Sams: An Overall Viewmentioning

confidence: 99%