Berlin 2005 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 35: Single molecules I
CPP 35.2: Talk
Wednesday, March 9, 2005, 10:00–10:15, TU C243
A single molecule study of intramolecular energy transfer in endcapped polyfluorenes — •K. Becker1, J. M. Lupton1, J. Feldmann1, A. C. Grimsdale2, and K. Müllen2 — 1Photonics and Optoelectr. Group, Physics and CeNS, LMU München — 2MPI für Polymerforschung, Mainz
Endcapped semiconducting polymers are not only promising materials for high-efficiency organic LEDs, but are also excellently suited for studies concerning the understanding of energy transfer in conjugated polymers. We present results on single molecule spectroscopy on a polyfluorene with perylene endcaps, which allow insight into the nature of inter- and intramolecular energy transfer. It is shown that the intramolecular energy transfer of the excitation from the polymer backbone to the perylene observed in single, isolated molecules is far less efficient and thus slower compared to the intermolecular energy transfer dominating in bulk films. The inefficiency of intramolecular energy transfer arises primarily due to the considerable inhomogeneous broadening of the polyfluorene. The efficiency can be increased by raising the temperature and increasing the linewidth [1]. Polarisation sensitive single molecule experiments give insight into the structural properties of the polymer chains by analysing the spectrally resolved photoluminescence of both the polyfluorene and the perylene endcaps.
[1] J. G. Müller et al., Phys. Rev. Lett. 91, 267403 (2003)