Self-assembled monolayers of polar molecules on Au(111) surfaces: distributing the dipoles
- 25 February 2010
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Physical Chemistry Chemical Physics
- Vol. 12 (17) , 4291-4294
Abstract
Quantum-mechanical calculations are performed to investigate the interface between Au(111) surfaces and self-assembled monolayers (SAMs) of organic thiols. Dipolar pyrimidine units act as building blocks to systematically tune the molecular dipole moments via the number of repeat units. The resulting work-function modifications and the energetic alignment of the frontier electronic states in the SAM with the Fermi level are analyzed. Compared to SAMs where strong dipole moments are realized only by end-group substitutions on otherwise non-polar molecules, an entirely different evolution with backbone length is found for the present systems, where dipoles are built directly into the backbone. In particular, the achievable work-function modifications depend on peculiarities in the relative alignment of the energy levels in the SAM and in the metal. We thus introduce an additional degree of freedom for tuning surface and interface electronic properties with functional self-assembled monolayers.Keywords
This publication has 22 references indexed in Scilit:
- Improving charge injection in organic thin-film transistors with thiol-based self-assembled monolayersOrganic Electronics, 2008
- Organic Electronic Devices and Their Functional InterfacesChemphyschem, 2007
- Improved morphology and charge carrier injection in pentacene field-effect transistors with thiol-treated electrodesJournal of Applied Physics, 2006
- Molecular orientation dependence of hole-injection barrier in pentacene thin film on the Au surface in organic thin film transistorApplied Physics Letters, 2006
- Cooperative effects and dipole formation at semiconductor and self-assembled-monolayer interfacesPhysical Review B, 2006
- Controlling Charge Injection in Organic Field-Effect Transistors Using Self-Assembled MonolayersNano Letters, 2006
- Electronic Structure of Metal/Molecule//Metal Junctions: A Density Functional Theory Study of the Influence of the Molecular Terminal GroupThe Journal of Physical Chemistry B, 2005
- Tuning of Metal Work Functions with Self‐Assembled MonolayersAdvanced Materials, 2005
- Controlling Schottky energy barriers in organic electronic devices using self-assembled monolayersPhysical Review B, 1996
- Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis setPhysical Review B, 1996