Dresden 2011 – scientific programme
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DS: Fachverband Dünne Schichten
DS 65: Organic Thin Films IV
DS 65.2: Talk
Friday, March 18, 2011, 16:15–16:30, GER 38
In situ studies of real-time changes in the optical spectrum of organic semiconducting thin films during growth — •Katharina Broch1, Ute Heinemeyer1, Alexander Hinderhofer1, Reinhard Scholz2, Alexander Gerlach1, and Frank Schreiber1 — 1Universität Tübingen, Institut für Angewandte Physik, Auf der Morgenstelle 10, 72076 Tübingen — 2Technische Universität Dresden, Institut für Angewandte Photophysik, 01062 Dresden
Fundamental issues related to organic semiconductors, such as interface effects and molecular coupling mechanisms, and in particular their influence on optical properties of the systems studied are still not thoroughly investigated. Real-time measurements are well suited for such studies since they enable the observation of possible transient structures and related features in the optical spectra of the films during growth. Using differential reflectance spectroscopy we performed real-time in situ studies of optical spectra during thin film growth of several prototype organic semiconductors (pentacene, perfluoropentacene, and diindenoperylene) on SiO2. These data provide insight into surface and interface effects that are of fundamental importance and of relevance for applications in organic electronics [1]. We observe spectral changes - such as energy shifts and new transitions in specific systems - that decay inversely proportional to the film thickness in the simplest approximation, caused by the different molecular environment and structural changes within the first few monolayers with respect to the bulk.
U. Heinemeyer et al., Phys. Rev. Lett. 104, 257401 (2010)