Scanning tunneling microscopy studies of self-assembled monolayers of alkanethiols on gold

Stranick, Stephan J.; Kamna, M. M.; Krom, K.R.; Parikh, Atul N.; Allara, David L.; Weiss, Paul S.

doi:10.1116/1.587689

Cited by 36 publications

(22 citation statements)

References 9 publications

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“…Thus, if the EOPRD changes with film growth it can only be the case that the electrons are not confined to the volume of a single colloid but are mobile within the aggregated domains. Electron mobility in this system is also consistent with the fact that electrons exhibit enhanced tunneling probability (vs vacuum) through functionalized alkane chains. − However, the electron dynamics in colloidal Au films are different than in bulk metals where electrons are fully mobile. Specifically, the apparent non-zero intercept of the curve in Figure b suggests that even for films with the greatest aggregation ( i .…”

Section: Resultssupporting

confidence: 72%

Electronic Relaxation Dynamics in Coupled Metal Nanoparticles

et al. 1997

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This paper reports the results of hot-electron lifetime measurements in a series of thin films prepared by wet chemistry techniques from 12-nm colloidal Au nanoparticles. The films, which vary in thickness and domain (or aggregate) size, are studied by a combined approach of femtosecond optical spectroscopy and scanning probe microscopy. Atomic force microscope measurements are used to characterize the samples and quantify the film's growth pattern. Time-resolved laser spectroscopy measurements are used to determine hot-electron lifetimes. The dependence of the hot-electron lifetimes on the colloid film's structure is analyzed; the lifetimes range from 1 to 3 ps and decrease with greater aggregation. The lifetime is shown to vary in a predictable manner with the film's growth, and a model is presented to describe this relationship. This model allows for the prediction of hot-electron lifetimes over a broad range of film thicknesses and obtains asymptotic agreement with previous experimental results for Au polycrystalline films. Additionally, physical insight into the processes responsible for the range of lifetimes is obtained through an analysis that takes into account two competing phenomena: electron inelastic surface scattering (ISS), which tends to increase electron−phonon coupling with decreasing domain size, and electron oscillation−phonon resonance detuning (EOPRD), which tends to decrease it. The relative contributions of each of these processes has been estimated and shown to agree with the theoretically-predicted tends. Finally, these results have implications for the nature of interparticle coupling and electron mobility. Specifically, they are consistent with and can be taken as evidence for an intercolloid electron conduction mechanism based on activated hopping. In short, the data presented herein and their analysis in terms of a size-dependent ISS and EOPRD shows that in thin films Au colloids aggregate in such a way as to be electronically coupled with one another while being physically separated by organic insulating groups. The films do, however, maintain physical characteristics and electronic influence based on the colloids from which they are built.

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Section: Resultssupporting

confidence: 72%

Electronic Relaxation Dynamics in Coupled Metal Nanoparticles

et al. 1997

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“…AuC n X has been studied using a plethora of analytical techniques and has been at least twice reviewed. , Of the techniques employed, scanning tunneling microscopy (STM) is unique in its ability to characterize structure, nondestructively, in direct space, and with routine single-molecule or single-atom resolution. , This review will not address all experimental and theoretical analyses, only those that employed STM to study AuC n X. − ...…”

Section: Introductionmentioning

confidence: 99%

Characterization of Organosulfur Molecular Monolayers on Au(111) using Scanning Tunneling Microscopy

1997

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“…A central theme in nanotechnology is to be able to understand and to manipulate materials at the single-molecule level to advance current technologies and to create new technologies. Self-assembled monolayers (SAMs), in which a single layer of molecules is immobilized on a surface, have often served as platforms for probing the effects of the local environment on molecular structure and function as well as for the development of new materials with distinct physical and chemical properties. − …”

Section: Introductionmentioning

confidence: 99%

Surface Structure and Electron Transfer Dynamics of the Self-Assembly of Cyanide on Au{111}

et al. 2016

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A vibronic resonance between Au{111} surface states and adsorbed CN vibrations has been predicted, which we target for study. We have formed stable monolayers of cyanide on Au{111} and observe a hexagonal close-packed lattice with a nearest neighbor distance of 3.8 ± 0.5 Å. Cyanide orients normal to the surface attached via a Au−C bond. We show that the substrate−molecule coupling is particularly strong, leading to ultrafast electron transfer from the cyanide molecules to the Au{111} substrate as measured by resonant Auger spectroscopy using the core−hole clock method. The CN/Au{111} system is a simple example of a strongly interacting adsorbate−substrate system and will be the subject of a number of further studies, as discussed.

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Scanning tunneling microscopy studies of self-assembled monolayers of alkanethiols on gold

Cited by 36 publications

References 9 publications

Electronic Relaxation Dynamics in Coupled Metal Nanoparticles

Electronic Relaxation Dynamics in Coupled Metal Nanoparticles

Characterization of Organosulfur Molecular Monolayers on Au(111) using Scanning Tunneling Microscopy

Surface Structure and Electron Transfer Dynamics of the Self-Assembly of Cyanide on Au{111}

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