Berlin 2008 – scientific programme

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SYSA: Symposium Tayloring Organic Interfaces: Molecular Structures and Applications

SYSA 5: Poster Session SYSA

SYSA 5.34: Poster

Tuesday, February 26, 2008, 14:30–20:00, Poster A

Solution-processed OFET with pentacene layer — •Andrei Herasimovich, Carsten Geigengack, Ingo Hörselmann, and Susanne Scheinert — TU Ilmenau, Germany

The solubility is one important property of organic semiconductors for the low cost preparation of the polymer layers from solution. However, many organic materials with high charge carrier mobility such as pentacene are insoluble in organic solvents at room temperature. Our goal was to investigate electrical properties of organic field effect transistors (OFET) based on a pentacene semiconductor film obtained from soluble precursor (N -Acethyl -6,13 -epithioimino -6 -13 -aihydropentacene -S -Oxide). Pentacene films were fabricated by spin-coating from 1-2%(m/m) precursor in a chloroform solution followed by annealing at 130-200^∘C under a nitrogen atmosphere to convert the precursor to pentacene. The conversion was confirmed by XPS and GDOES (glow discharge optical emission spectroscopy) element analysis and by UV-VIS optical measurements. We have found that the annealing conditions influence strongly the electrical properties of the OFETs. However, transistors with optimized annealing conditions have a good inverse subthreshold slope of 0.2 V/dec, an on/off ratio of 10⁶ and high charge carrier mobilities of 0.01-0.1 cm²/Vs. We demonstrate also that OFET characteristics depend on insulator and contact properties.