Energy-level Alignment of Aryl Thiols Chemisorbed on Metal Surfaces: Implications for Molecular Electronic Junctions
27 Sep 2007 | Online Presentations | Contributor(s): Roger D. van Zee
Charge-transport through the interface is a key part of the behavior of any electronic junction. One interface property important to molecular-electronic junctions is the energetic mismatch between the conductive levels of the molecule and the Fermi level of the contact material. This seminar will discuss the energy-level alignment of para (phenylene-ethynylene) (sometimes called =93molecular wires=94) chemisorbed on metal surfaces. One- and two-photon and inverse photoemission spectra have been used to determine the energy-level alignment for these monolayers. The nature of the valence states can be established by comparing the monolayer spectra to those of the
isolated molecule. The effects of molecular length, chemical substitution, and substrate have been studied. The observed energy-level alignment can be qualitatively understood in terms of a localized interface dipole. The implications of these results for the design of molecular electronic junctions are considered.