Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 45: Organische Dünnschichten IV

O 45.9: Vortrag

Dienstag, 8. März 2005, 17:45–18:00, TU EB301

Orientation of substituted phthalocyanines on polycrystalline gold: distinguishing between the first layers and thin films — •Indro Biswas¹, Heiko Peisert¹, Lei Zhang¹, Martin Knupfer², Michael Hanack³, Danilo Dini³, Thomas Schmidt⁴, David Batchelor⁴, and Thomas Chassé¹ — ¹Universität Tübingen, IPC, Auf der Morgenstelle 8, 72076 Tübingen — ²Leibniz Institute for Solid State and Materials Research Dresden, P.O. Box 270116, , D-01171 Dresden — ³Universität Tübingen, Inst. Organ. Chem., Auf der Morgenstelle 18, D-72076 Tübingen — ⁴Universität Würzburg, Am Hubland, D-97074 Würzburg

We have studied the molecular orientation of substituted phthalocyanines (Pc’s) grown as ultra-thin films on a polycrystalline gold substrate. For about 10-20 nm thick films of Pc’s with small substituents, a high degree of molecular orientation has been observed. Similar to unsubstituted PcCu, the orientation of the molecules is perpendicular to the sample surface. Importantly, however, the molecular orientation is different for low coverages, the molecules lie on the substrate surface. Thus, the orientation of organic molecules directly at the interface cannot be deduced from the orientation in typical thin film systems. The growth mode is discussed in terms of different molecule-molecule and molecule-substrate interactions. We are grateful for helpful discussions and the synthesis of organic materials to M. Cook and I. Chambrier. Financial support by BESSY is acknowledged.