Regensburg 2007 – wissenschaftliches Programm
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SYOE: Symposium Organic Thin Film Electronics: From Molecular Contacts to Devices
SYOE 8: Poster Session SYOE
SYOE 8.69: Poster
Dienstag, 27. März 2007, 18:00–20:00, Poster B
New electron acceptor material for organic hole transport materials — •Ralf Krause1,2, Günter Schmid2, Stefan Seidel1,2, Arvid Hunze2, and Albrecht Winnacker1 — 1Department of Materials Science VI, University of Erlangen-Nuremberg, Germany — 2Siemens AG, CT MM 1, Günther-Scharowsky-Str. 1, 91052 Erlangen, Germany
The injection and transport properties of organic materials are of fundamental interest to improve the understanding of small molecule OLEDs. In the past years it was shown that the use of electrically doped transport layers leads to devices with low driving voltages, which is essential to achieve high power efficiencies. We evaluated a p-doping material with an evaporation temperature lower than 300°C and investigated its properties in hole-only devices and OLEDs. N,N-di(naphthalen-2-yl)-N,N-diphenyl-benzidine (NPB), a commercial hole-transport material is used as matrix for this doping material. Both materials were coevaporated with different concentrations. The best possible concentration increases the conductivity more than 5 orders of magnitude compared with pure NPB. The transparency of the doped hole transport layer is much higher than for the commonly used organic dopants like 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) due to its lower intensity charge transfer band.