Dresden 2017 – wissenschaftliches Programm
CPP 59.1: Hauptvortrag
Donnerstag, 23. März 2017, 15:00–15:30, ZEU 222
Charge transport modeling in disordered molecular semiconductors: from the molecule to the device — Andrea Massé1, Feilong Liu1, Pascal Friederich2, Franz Symalla2, Velimir Meded2, Wolfgang Wenzel2, Reinder Coehoorn1, and •Peter A. Bobbert1 — 1Department of Applied Physics, Technische Universiteit Eindhoven, Eindhoven, The Netherlands — 2Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany
The modeling of charge transport in disordered organic molecular semiconductors has been hampered up to now by the huge difference between the molecular scale and the device scale at which the transport is studied experimentally. Here, we employ a multi-scale approach in which microscopic information based on ab initio calculations of the morphology, energy disorder, reorganization energies, and charge transfer integrals is stochastically expanded to a scale that allows charge transport calculations at the device scale. We demonstrate the approach for electron and hole transport in a few important molecular semiconductors. For hole-only α-NPD devices, we find a remarkable agreement between predicted and measured temperature-dependent current-voltage and impedance spectroscopy characteristics, without the need to adjust a single parameter. We study the effects of spatial energy correlations and superexchange on charge transport and find that the latter can significantly increase the conductance of host-guest systems used in the emission layers of organic light-emitting diodes.