Münster 1997 – wissenschaftliches Programm

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DS: Dünne Schichten

DS 17: Optische Eigenschaften I

DS 17.6: Vortrag

Dienstag, 18. März 1997, 13:00–13:15, ZB

Transient Luminescence of Ultrathin Organic Films : Investigation of Monomer and Excimer Dynamics — •M. Kurpiers, O. Kowalke, K. Puech, H. Fr"ob, and K. Leo — Institut f"ur Angewandte Photophysik, Technische Universit,t Dresden, Mommsenstraae 13, D-01062 Dresden

Organic thin films are important materials for applications in optoelectronics, nonlinear optics etc. We describe detailed transient luminescence investigations of ultrathin (less than a monolayer–a few monolayers) films of N,N’–dimethylperylene–3,4:9,10–bis–dicarboximide (MePTCDI) on various substates. We find that both aggregates and single isolated molecules can be present in the same sample [1]. The emission from the aggregates is interesting from a fundamental point of view in that it is similar to transitions that have been observed previously in crystals with a dimeric structure, eg. α–perylene. The model that was used for the explanation of these emissions is, however, in disagreement with our data. The temporal profiles of the transitions are never simply single or bi–exponential but have a more complicated form. Reasons for this behaviour, along with a possible model to account for the aggregate transition, will be discussed.

[1] K. Puech, H. Fr"ob, M. Hoffmann and K. Leo, Opt. Lett 21, 1606, (1996)