Regensburg 2013 – scientific programme
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DS: Fachverband Dünne Schichten
DS 16: Organic Thin Films I
DS 16.6: Talk
Tuesday, March 12, 2013, 16:00–16:15, H32
Effect of fluorination: Optical properties of Rubrene in films and solution — •Falk Anger1, Reinhard Scholz2, Evelyn Adamski1, Katharina Broch1, Alexander Gerlach1, Yoichi Sakamoto3, Toshiyasu Suzuki3, and Frank Schreiber1 — 1Institut für Angewandte Physik, Auf der Morgenstelle 10, 72076 Tübingen — 2Institut für Angewandte Photophysik, TU Dresden, 01069 Dresden — 3Institute for Molecular Science, Myodaiji, Okazaki 444-8787, Japan
A promising way to modify the electronic levels of organic semiconductors is partial or complete fluorination, potentially with further opportunities opening up by mixing these compounds with the hydrogenated version [1]. We present the optical properties of newly synthesised fully (C42F28) and half-fluorinated (C42F14H14) rubrene, both in thin films and as monomers in solution, and compare them to hydrogenated rubrene (C42H28, RUB) [2]. Remarkably, all three compounds show similar optical absorption bands and photoluminescence line shapes. The results are interpreted with density functional calculations of the orbital energies and time-dependent density functional theory for the HOMO-LUMO transition [3]. Red shifts induced by the surrounding solvent or organic thin films remain much smaller than for polyacenes, in keeping with previous observations for rubrene and existing models for the solvatochromic shifts. We discuss implications for applications of the new material.