Regensburg 2016 – scientific programme

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DS: Fachverband Dünne Schichten

DS 9: Organic Thin Films II

DS 9.4: Talk

Monday, March 7, 2016, 15:45–16:00, H11

Thermoelectric characterization of doped organic semiconductors — •Bernhard Nell and Koen Vandewal — Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden, Germany

The introduction of p- and n-doped layers into the device structure of opto-electronic devices plays a crucial role in improving device performance. In this way, the charge carrier extraction or injection from or into the organic photo-active layer is improved and ohmic losses are reduced. Molecular doping of organic host materials increases the conductivity of the transport layers and moves the Fermi level to the appropriate position enabling electron or hole selectivity. In this work, we use thermovoltage (Seebeck effect) and temperature-dependent conductivity measurements to determine the dominating type of charge carriers introduced by the dopant and to gain insight into the position of the transport level with respect to the Fermi level. The investigation of fullerene dopants with a different degree of fluorination in various amorphous host materials allows us to tune the energy level offsets between host and dopant and study their influence on the Fermi level position and overall doping efficiency systematically.