title: Resonance and localization effects at a dipolar organic semiconductor interface.
abstract: The image state manifold of the dipolar organic semiconductor vanadyl naphthalocyanine (VONc) on highly oriented pyrolytic graphite is investigated by angle-resolved two-photon photoemission (AR-TPPE) spectroscopy in the 0-1 monolayer regimes. Interfacial charge-transfer from the image potential state of clean graphite populates a near-resonant VONc anion level, identifiable by the graphite image potential state by its distinct momentum dispersion obtained from AR-TPPE. This affinity level is subject to depolarization by the neighboring molecules, resulting in stabilization of this state with coverage. Near a coverage of one monolayer, a hybrid image potential/anion state is also formed, showing progressive localization with coverage. Intensities for all these features develop rather differently with molecular coverage, pointing towards the different types of charge-transfer interactions at play at this interface.
authors.affiliation: Department of Chemistry, The University of Arizona, 1306 E. University Blvd., Tucson, Arizona 85721, USA.
authors.forename: Mary P
authors.initials: MP
authors.lastname: Steele
authors.forename: Leah L
authors.initials: LL
authors.lastname: Kelly
authors.forename: Nahid
authors.initials: N
authors.lastname: Ilyas
authors.forename: Oliver L A
authors.initials: OL
authors.lastname: Monti
mesh_terms: D006108:Graphite / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D012666:Semiconductors; D013499:Surface Properties; D014639:Vanadium / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D014639:Vanadium; D006108:Graphite