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Title: Quantitatively identical orientation-dependent ionization energy and electron affinity of diindenoperylene

Molecular orientation dependences of the ionization energy (IE) and the electron affinity (EA) of diindenoperylene (DIP) films were studied by using ultraviolet photoemission spectroscopy and inverse photoemission spectroscopy. The molecular orientation was controlled by preparing the DIP films on graphite and SiO{sub 2} substrates. The threshold IE and EA of DIP thin films were determined to be 5.81 and 3.53 eV for the film of flat-lying DIP orientation, respectively, and 5.38 and 3.13 eV for the film of standing DIP orientation, respectively. The result indicates that the IE and EA for the flat-lying film are larger by 0.4 eV and the frontier orbital states shift away from the vacuum level compared to the standing film. This rigid energy shift is ascribed to a surface-electrostatic potential produced by the intramolecular polar bond (>C{sup −}-H{sup +}) for standing orientation and π-electron tailing to vacuum for flat-lying orientation.
Authors:
; ; ; ; ; ;  [1] ; ; ; ;  [2]
  1. Graduate School of Advanced Integration Science, Chiba University 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan)
  2. Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan)
Publication Date:
OSTI Identifier:
22217767
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 103; Journal Issue: 25; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; AFFINITY; EV RANGE 01-10; GRAPHITE; HYDROGEN IONS 1 PLUS; IONIZATION; ORGANIC COMPOUNDS; ORIENTATION; PHOTOELECTRON SPECTROSCOPY; PHOTOEMISSION; POTENTIALS; SILICA; SILICON OXIDES; SUBSTRATES; SURFACES; TAILINGS; THIN FILMS; ULTRAVIOLET RADIATION