Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 46: [DS] Organic electronics and photovoltaics: electronic properties II (jointly with CPP, HL, O)
O 46.6: Vortrag
Mittwoch, 28. März 2012, 12:45–13:00, H 2032
Local Investigations on Air-stable n-Channel Perylene Diimide Based OFETs on Surface Modified SiOx Dielectric — •Franziska Lüttich1, Daniel Lehmann1, Harald Graaf1,2, Christian von Borczyskowski1, and Dietrich R. T. Zahn1 — 1Chemnitz University of Technology, Institute of Physics, Germany — 2Now at University Kassel, Institute of Chemistry, Germany
Organic semiconducting materials are interesting for low-cost and flexible applications like organic light-emitting diodes, organic solar cells, and organic field-effect transistors (OFETs). Stability and low mobilities are the most limiting properties for these applications. Surface modifications changing the surface energy of the dielectric in OFETs influences the orientation of the organic molecules and therefore the mobilities. The surface energy can be determined by water contact angle measurements.
In order to investigate the influence of the surface energy we used OFET substrates from Fraunhofer IPMS and varied the water contact angle of the 100 nm thick dielectric of thermal silicon dioxide in the range from 20∘ to 55∘. Thereafter the air-stable Polyera ActivInk™ N1200 (PDI8-CN2) was deposited by spin coating. The topography was determined using an Atomic Force Microscope (AFM). The electrical characterization was performed by DC measurements and additionally locally resolved by Kelvin Probe Force Microscopy (KPFM) to obtain an insight in the local surface potential and the contact resistances. The determined electron mobility were found to change with varying water contact angle.