title: Optimized hole injection with strong electron acceptors at organic-metal interfaces.
abstract: The energy-level alignment at interfaces between three electroactive conjugated organic materials and Au was systematically varied by adjusting the precoverage of the metal substrate with the electron acceptor tetrafluoro-tetracyanoquinodimethane (F4-TCNQ). Photoelectron spectroscopy revealed that electron transfer from Au to adsorbed F4-TCNQ was responsible for lowering the hole-injection barrier by as much as 1.2 eV. This novel interface modification scheme is independent of the charge transfer complex formation ability of the organic materials with the electron acceptor.
authors.affiliation: Institut für Physik, Humboldt-Universität zu Berlin, Newtonstrasse 15, D-12489 Berlin, Germany. norbert.koch@physik.hu-berlin.de
authors.forename: Norbert
authors.initials: N
authors.lastname: Koch
authors.forename: Steffen
authors.initials: S
authors.lastname: Duhm
authors.forename: Jürgen P
authors.initials: JP
authors.lastname: Rabe
authors.forename: Antje
authors.initials: A
authors.lastname: Vollmer
authors.forename: Robert L
authors.initials: RL
authors.lastname: Johnson