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O: Fachverband Oberflächenphysik

O 27: Poster Session I (Methods: Scanning probe techniques; Methods: Atomic and electronic structure; Methods: Molecular simulations and statistical mechanics; Oxides and Insulators: Clean surfaces; Oxides and Insulators: Adsorption; Oxides and Insulators: Epitaxy and growth; Semiconductor substrates: Clean surfaces; Semiconductor substrates: Epitaxy and growth; Semiconductor substrates: Adsorption; Nano- optics of metallic and semiconducting nanostructures; Electronic structure; Methods: Electronic structure theory; Methods: other (experimental); Methods: other (theory); Solutions on surfaces; Epitaxial Graphene; Surface oder interface magnetism; Phase transitions; Time-resolved spectroscopies)

O 27.84: Poster

Dienstag, 24. März 2009, 18:30–21:00, P2

Electronic fine structures of perfluoropentacene films by ultraviolet photoelectron spectroscopy — •Shunsuke Hosoumi, Shinichi Nagamatsu, Satoshi Kera, and Nobuo Ueno — Chiba University, Japan

Pentacene (PEN) and perfluoropentacene (PFP) are currently the most potential conjugated organic molecules as active materials in novel electronic devices[1]. The intramolecular charge reorganization energy (λ), which is related to the electron-phonon coupling, is important parameter for efficient transport of charges in organic materials and across related interfaces. However, λ has been discussed based on highly-resolved spectra of gas-phase molecules [2]. Recently, we have succeeded to assess λ directly from the fine features in high-resolution UPS of organic solid systems by fabricating a well-ordered monolayer deposited on graphite [3].In this paper, we compare the electronic structures of the well-ordered monolayer both for PEN/graphite and PFP/graphite. The UPS band derived from the highest occupied molecular orbital (HOMO) for both monolayer systems shows fine structures clearly, indicating the molecular vibrational modes strongly couple to photoelectron (HOMO hole). The λ for PFP is about two times larger than PEN. The take-off angle dependence of the UPS spectra that the Franck-Condon principle is not strictly satisfied in the photoionization process will be discussed.

[1] Y. Inoue et al, Jpn, J. Appl. Phys. 44, 3663 (2005). [2] J-L. Bredas et al, Chem. Rev. 104, 4971 (2004). [3] H. Yamane et al, Phys. Rev. B 72, 153412 (2005).