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CPP: Chemische Physik und Polymerphysik

CPP 23: POSTER Functional Organic Thin Films

CPP 23.44: Poster

Donnerstag, 30. März 2006, 17:00–19:00, P2

Kinetic Monte Carlo Model of Space Charge Limited Currents in Organic Semiconductors — •Michael Müller, Karsten Albe, Yuri Genenko, Frederik Neumann, Roland Schmechel, and Heinz von Seggern — Institut für Materialwissenschaft, Technische Universität Darmstadt, D-64287 Darmstadt

Kinetic Monte Carlo (KMC) simulations have proven to be a valuable tool for investigating the characteristics of hopping charge transport in disordered organic semiconductors [1]. However, owing to their long range nature, electrostatic interactions between the individual charge carriers commonly had to be neglected. In consequence, the applicability of the KMC method has been restricted to hopping transport at low charge carrier densities where interactions are regarded negligible, as it is the case for the injection limited regime.

Here, we present a KMC model that fully includes the electrostatic interactions between the charge carriers. Using this model, we investigate the current-voltage characteristic and the field dependence of the charge carrier mobility in the space charge limited regime for hopping systems with various degrees of disorder. In doing so, different models for the microscopic hopping rates (Miller-Abrahams hopping in the exact and the commonly used approximated formulation as well as the small polaron model) are applied. A significant dependence of the obtained characteristics on the choice of model is found and discussed.

[1] H. Bässler, phys. stat. sol. (b) 175, 15 (1993)