Hamburg 2001 – wissenschaftliches Programm

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SYOF: Organische Festkörper

SYOF 5: Poster Session

SYOF 5.16: Poster

Dienstag, 27. März 2001, 17:00–19:00, Aula S3

Simulation of charge carrier transport in disordered molecular solids — •Jörg Stephan and Ludwig Brehmer — Institut für Physik, Physik kondensierter Materie, Universität Potsdam, PSF 601553, D-14415 Potsdam

We study the effect of spatial disorder, anisotropy and sample orientation on the field-dependent mobility of charge carriers using a dynamic Monte Carlo simulation. Our transfer rate is based on a polaronic model of phonon-assisted hopping in an effective diabatic potential (Marcus-theory). We find that our simulations, in contrast to the Gaussian Disorder Model or the Correlated Disorder Model, do not require unphysical model parameters or correlated disorder to explain experimental data for the field and temperature dependence of mobilities. Our simulations show, that no energetic disorder is necessary to fit experiments; a clear transition from a 3-D diffusion and drift limited mobility to a quasi 1-D drift limited process with increasing external fields in the presence of spatial disorder can be observed; a well-controlled degree of disorder can under certain conditions increase carrier mobility and simulated mobilities on a regular lattice depend strongly on the direction of the external field with respect to the lattice in a non-trivial and field-dependent manner.