Interfacial electrostatics of self-assembled monolayers of alkane thiolates on Au(111)

Work function modification and molecular level alignments

Roger Rousseau, V. De Renzi, R. Mazzarello, D. Marchetto, R. Biagi, S. Scandolo, U. Del Pennino

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

We have isolated at T <150 K a weakly adsorbed dimethyl disulfide (DMDS) layer on Au(111) and studied how the vibrational states, S core hole level shifts, valence band photoemission, and work function measurements evolve upon transforming this system into chemisorbed methylthiolate (MT) self-assembled monolayers (SAM) by heating above 200 K. By combining these observations with detailed theoretical electronic structure simulations, at the density functional level, we have been able to obtain a detailed picture of the electronic interactions at the interface between Au and adsorbed thiolates and disulfides. All of our measurements may be interpreted with a simple model where MT is bound to the Au surface with negligible charge transfer. Interfacial dipoles arising from Pauli repulsion between molecule and metal surface electrons are present for the weakly adsorbed DMDS layer but not for the chemisorbed species. Instead, for the chemisorbed species, interfacial dipoles are exclusively controlled by the molecular dipole, its interaction with the dipoles on neighboring molecules, and its orientation to the surface. The ramifications of these results for alignment of molecular levels and interfacial properties of this class of materials are discussed.

Original languageEnglish
Pages (from-to)10862-10872
Number of pages11
JournalJournal of Physical Chemistry B
Volume110
Issue number22
DOIs
Publication statusPublished - Jun 8 2006

Fingerprint

Alkanes
Self assembled monolayers
Paraffins
alkanes
Electrostatics
disulfides
alignment
electrostatics
dipoles
Molecules
Photoemission
Valence bands
Disulfides
Electronic structure
Charge transfer
Metals
vibrational states
metal surfaces
Heating
molecules

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Interfacial electrostatics of self-assembled monolayers of alkane thiolates on Au(111) : Work function modification and molecular level alignments. / Rousseau, Roger; De Renzi, V.; Mazzarello, R.; Marchetto, D.; Biagi, R.; Scandolo, S.; Del Pennino, U.

In: Journal of Physical Chemistry B, Vol. 110, No. 22, 08.06.2006, p. 10862-10872.

Research output: Contribution to journalArticle

Rousseau, Roger ; De Renzi, V. ; Mazzarello, R. ; Marchetto, D. ; Biagi, R. ; Scandolo, S. ; Del Pennino, U. / Interfacial electrostatics of self-assembled monolayers of alkane thiolates on Au(111) : Work function modification and molecular level alignments. In: Journal of Physical Chemistry B. 2006 ; Vol. 110, No. 22. pp. 10862-10872.
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