Berlin 2005 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 16: Time-resolved phenomena
CPP 16.5: Vortrag
Montag, 7. März 2005, 17:30–17:45, TU C243
Femtosecond near-field spectroscopy of conjugated polymers and conjugated polymer nanospheres — •Christoph Lienau1, Kerstin Müller1, Dario Polli2, Christoph Gadermaier2, Giulio Cerullo2 und Guglielmo Lanzani2 — 1Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin — 2Politecnico di Milano, Dipartimento di Fisica, 20133 Milano, Italy
Recently, ultrafast time-resolved spectroscopy has contributed significantly to understanding the optical and electronic properties of conjugated polymers. The morphology of such materials is, however, often complex and gives rise to order effects and nanoscale size effects, which are key issues in the ongoing drive towards miniaturization of polymer-based electronic and photonic structures. Adding spatial resolution beyond the diffraction limit to ultrafast spectroscopy can thus improve the basic understanding of polymer nanostructures as well as different engineering aspects. We apply near-field scanning optical microscopy using femtosecond pulses to study the spatially resolved ultrafast photoexcitation dynamics of m-LPPP, a prototypical blue emitting polymer. Two-color pump-probe experiments with a spatial resolution of 250 nm and a time resolution of up to 200 fs are used to compare a solution-cast bulk film to a nanosphere film of the same polymer. We identify sub-micron domains with significant differences in the decay behavior of the photoexcited species. We attribute this behaviour to variations in orientational alignment of polymer chains.