AVS 51st International Symposium
    Organic Films and Devices Thursday Sessions
       Session OF+NS-ThM

Paper OF+NS-ThM9
Oligomer Length Dependent Study of Metal-Molecule Interactions in Model Molecular Wire Systems

Thursday, November 18, 2004, 11:00 am, Room 304C

Session: Molecular Electronics
Presenter: C.D. Zangmeister, NIST
Authors: C.D. Zangmeister, NIST
S.W. Robey, NIST
R.D. Van Zee, NIST
Correspondent: Click to Email
Interactions at the molecule-contact interface perturb the molecular orbitals important for electron transport in conjugated systems. These perturbations are particularly important for the nanometer size junctions applicable in molecular-scale electronics. This study looks at the variation of the occupied electronic structure of fully conjugated model molecular wire compounds as a function of molecular length. Specifically, the number of phenyl rings was varied from a single ring to three rings in unsubstituted phenylene ethynylene monolayers chemisorbed on Au using ultraviolet photoemission spectroscopy. This provides a qualitative picture of the extent of perturbation of the electronic structure due to thiol coupling and the variation of the molecular @pi@ levels important for electron transport as a function of the degree of conjugation. These data show a shift towards the Au Fermi levels in the @pi@ levels by more than an eV as the conjugation length is increased. These observations will be discussed in terms of previous electron transport investigations of these compounds adsorbed on Au.