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Lecture P. Bobbert


18 March 2005 FWN-Building 5116.0107, Nijenborgh 4, 9747 AG, Groningen
Speaker:Dr. P. Bobbert
Affiliation:Group Polymer Physics and Dutch Polymer Institute, TUE
Title:Polarons in semiconducting polymers
Date:Fri Mar 18, 2005
Location:FWN-Building 5116.0107
Host:R. Broer
Telephone:+31 50 363 4374


We present a study of electron (hole) - phonon interaction and polaron formation in semiconducting polymers within an extended Holstein model. A minimization of the lowest electronic state of this Hamiltonian with respect to lattice degrees of freedom yields the polaronic ground state. Input arameters of this Hamiltonian are obtained from ab-initio calculations based on density-functional theory. We calculate optical phonon modes and the coupling constants of these modes to the HOMO and LUMO bands (highest occupied and lowest unoccupied molecular orbitals, respectively). For the studied polymers (polythiophene - PT, poly(phenylenevinylene) - PPV, poly(para-phenylene) - PPP) the polaron binding energy, its size and the lattice deformation as a function of conjugation length have been determined. Self-trapped polarons are found for long conjugation lengths. Energies of prominent PPV modes involved in polaron formation agree with infrared spectra.
Last modified:22 October 2012 2.30 p.m.