Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 38: Organic electronics and photovoltaics II (DS, jointly with CPP, HL, O)

HL 38.4: Talk

Tuesday, March 12, 2013, 10:15–10:30, H32

Correlation of morphology and electronic properties of MoO₃ doped CBP layers I: TEM and electrical properties — •Daniela Donhauser^{1, 2}, Levin Dieterle^{1, 2}, Paul Heimel^{3, 2}, Tobias Glaser^{3, 2}, Maybritt Kühn^{4, 2}, Mustapha Al-Helwi^{5, 2}, Rasmus R. Schröder⁶, Eric Mankel^{4, 2}, Michael Kröger^{1, 2}, and Wolfgang Kowalsky^{1, 2} — ¹Institut für Hochfrequenztechnik, TU Braunschweig, Braunschweig — ²InnovationLab GmbH, Heidelberg — ³Kirchhoff-Institut für Physik, Universität Heidelberg, Heidelberg — ⁴Institut für Materialwissenschaft, TU Darmstadt, Darmstadt — ⁵BASF SE, Ludwigshafen — ⁶CellNetworks, Universität Heidelberg

Since electrochemical doping can significantly improve the performance of organic devices, the understanding of the fundamental properties of doped thin films is crucial. For a variety of different material systems a very low doping efficiency was observed, although from energetical considerations a very efficient charge transfer is expected. Using bright-field TEM and electron tomography we show for MoO₃-doped CBP ((4,4’-Bis(N-carbazolyl)-1,1’-biphenyl) thin films that this low doping efficiency is due to filament-like dopant agglomeration which can be controlled by changing the substrate temperature during the evaporation process [1]. The observed morphology is finally correlated with electrical properties like charge carrier density and mobility and depending on the dopant concentration an anisotropic charge transport is observed.
Donhauser et al., Adv. Funct. Mater., 2012, 10.1002/adfm.201202089