title: Single-Crystal Pentacene Valence-Band Dispersion and Its Temperature Dependence.
abstract: The electronic structures of the highest occupied molecular orbital (HOMO) or the HOMO-derived valence bands dominate the transport nature of positive charge carriers (holes) in organic semiconductors. In the present study, the valence-band structures of single-crystal pentacene and the temperature dependence of their energy-momentum dispersion relations are successfully demonstrated using angle-resolved ultraviolet photoelectron spectroscopy (ARUPS). For the shallowest valence band, the intermolecular transfer integral and effective mass of the holes are evaluated as 43.1 meV and 3.43 times the electron rest mass, respectively, at room temperature along the crystallographic direction for which the widest energy dispersion is expected. The temperature dependence of the ARUPS results reveals that the transfer integral values (hole effective mass) are enhanced (reduced) by ∼20% on cooling the sample to 110 K.
authors.affiliation: Department of Pure and Applied Chemistry, Graduate School of Science and Technology, Tokyo University of Science , 2641 Yamazaki, Noda 278-8510, Japan.
authors.forename: Yasuo
authors.identifier: http://orcid.org/0000-0001-5014-6858
authors.initials: Y
authors.lastname: Nakayama
authors.affiliation: Graduate School of Advanced Integration Science, Chiba University , 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Mizuno
authors.affiliation: Department of Pure and Applied Chemistry, Graduate School of Science and Technology, Tokyo University of Science , 2641 Yamazaki, Noda 278-8510, Japan.
authors.forename: Masataka
authors.initials: M
authors.lastname: Hikasa
authors.affiliation: Graduate School of Advanced Integration Science, Chiba University , 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: UVSOR Facility, Institute for Molecular Science (IMS), National Institutes of Natural Sciences , 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Matsunami
authors.affiliation: UVSOR Facility, Institute for Molecular Science (IMS), National Institutes of Natural Sciences , 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585, Japan.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Ideta
authors.affiliation: UVSOR Facility, Institute for Molecular Science (IMS), National Institutes of Natural Sciences , 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585, Japan.
authors.forename: Kiyohisa
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Graduate School of Advanced Integration Science, Chiba University , 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.|Center for Frontier Science, Chiba University , 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Ishii
authors.affiliation: Graduate School of Advanced Integration Science, Chiba University , 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Ueno