title: Effect of oxygen on the electronic structure of highly crystalline picene films.
abstract: The electronic structure of highly crystalline picene films with a standing-up orientation grown epitaxially on the Ag(110) surface was investigated. Upon exposure to oxgen gas, O(2) molecules incorporate at the interstitial sites within the a-b plane of the film. Features related to the highest three occupied molecular orbitals shift toward a lower binding energy which results in the inactivation of traps and the reduction of the charge injection barrier by about 1 eV. It is suggested that the highest two picene orbitals are inverted due to the strong interactions between the singly occupied oxygen π orbital and the highest occupied orbital of picene.
authors.affiliation: School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan. wang-y@jaist.ac.jp
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Simone
authors.initials: S
authors.lastname: Di Motta
authors.forename: Fabrizia
authors.initials: F
authors.lastname: Negri
authors.forename: Rainer
authors.initials: R
authors.lastname: Friedlein