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.

Interfacial electrostatics of self-assembled monolayers of alkane thiolates on Au(111): Work function modification and molecular level alignments / R., ROUSSEAU; DE RENZI, Valentina; R., MAZZARELLO; MARCHETTO, Diego; BIAGI, Roberto; S., SCANDOLO; DEL PENNINO, Umberto. - In: JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL. - ISSN 1520-6106. - STAMPA. - 110:(2006), pp. 10862-10872.

Interfacial electrostatics of self-assembled monolayers of alkane thiolates on Au(111): Work function modification and molecular level alignments

DE RENZI, Valentina;MARCHETTO, Diego;BIAGI, Roberto;DEL PENNINO, Umberto
2006

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.
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Interfacial electrostatics of self-assembled monolayers of alkane thiolates on Au(111): Work function modification and molecular level alignments / R., ROUSSEAU; DE RENZI, Valentina; R., MAZZARELLO; MARCHETTO, Diego; BIAGI, Roberto; S., SCANDOLO; DEL PENNINO, Umberto. - In: JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL. - ISSN 1520-6106. - STAMPA. - 110:(2006), pp. 10862-10872.
R., Rousseau; DE RENZI, Valentina; R., Mazzarello; Marchetto, Diego; Biagi, Roberto; S., Scandolo; DEL PENNINO, Umberto
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11380/310865
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