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Interface Fermi level pinning at contacts between PEDOT: PSS and molecular organic semiconductors
Heiko Peisert1, Andreas Petr, Lothar Dunsch
1University of Tübingen, IPC, Auf der Morgenstelle 8 72076 Tübingen, Germany. peisert@ipc.uni-tuebingen.de
Abstract:
Photoemission studies of interfaces between molecular organic semiconductors and the conducting polymer PEDOT:PSS [mixture of PEDOT (poly-3,4-ethylenedioxy-thiophene) and PSS (polystyrenesulfonate)] demonstrate that it is impossible to control the charge injection barriers at such contacts by either a systematic change of the work function of the conducting polymer or that of the organic semiconductor. Instead, these interfaces are, in all cases, characterized by a charge transfer across the interface and a resulting Fermi level pinning. Thus interfacial charge barriers do not explain observed changes in device parameters as a function of the work function of the polymer electrode.
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