Berlin 2005 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 20: Dynamics II
CPP 20.2: Talk
Tuesday, March 8, 2005, 11:30–11:45, TU C230
Charge and Energy Dynamics in Photo-Excited poly(para-phenylenevinylene) Systems — •Linus Gisslén1,2, Sven Stafström2, and Åsa Johansson2 — 1Institut für Physik, Technische Universität Chemnitz, Chemnitz, Germany — 2Department of Physics and Measurement Technology, Linköping, Sweden
We report results from simulations of charge and energy dynamics in poly(para-phenylenevinylene) (PPV) and PPV interacting with C60. The simulations were performed by solving the time-dependent Schrödinger equation and the lattice equation of motion simultaneously and nonadiabatically. The electronic system and the coupling of the electrons to the lattice were described by an extended three-dimensional version of the Su-Schrieffer-Heeger model, which also included an external electric field. Electron and lattice dynamics following electronic excitation at different energies have been simulated. The effect of additional lattice energy was also included in the simulations. Our result show that both exciton diffusion and transition from high to lower lying excitation are stimulated by increasing the lattice energy. Also field induced charge separation occurs faster if the lattice energy is increased. This separation process is highly nonadiabatic and involves a significant rearrangement of the electron distribution. In the case of PPV coupled to C60, we observe a spontaneous charge separation. The separation time is in this case limited by the local concentration of C60 molecules close to the PPV chain.