Regensburg 2002 – wissenschaftliches Programm
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SYOH: Organische Halbleiter
SYOH 7: Poster
SYOH 7.47: Poster
Montag, 11. März 2002, 18:00–21:00, C
Spectroscopy of single conjugated polymer chains — •J. G. Müller1, G. Raschke1, U. Lemmer1, J. Feldmann1, and U. Scherf2 — 1Lehrstuhl für Photonik und Optoelektronik, Ludwig-Maximilians-Universität München, 80799 München — 2Institut für Physikalische und Theoretische Chemie, Universität Potsdam, 14476 Golm
The nature of electronic eigenstates in conjugated polymers is heavily debated. The experimental investigation is hampered by the high degree of disorder and the strong inhomogeneous broadening of the optical spectra. More insight can be obtained by means of single molecule spectroscopy. We use this technique to investigate the emission properties of single chains of a ladder-type methyl-substituted poly(p-phenylene) (MeLPPP). The polymer is diluted in a polystyrene-matrix. At low temperature (T=5 K) the emission linewidth is well below 10 meV, which is one order of magnitude smaller than the ensemble linewidth. The corresponding dephasing time T2 of the π−π*–transition amounts to 140 fs at this temperature. At room-temperature the linewidth increases to 0.1 eV, a value close to the ensemble linewidth. Polarization dependent measurements of the single-molecule spectra access intrachain energy transfer processes.