Berlin 2008 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 35: Nanostructured block copolymer films (SYSA 8)
DS 35.5: Vortrag
Donnerstag, 28. Februar 2008, 18:15–18:30, H 2032
Temperature dependent X-ray diffraction studies of low and high molecular weight Poly(3-hexylthiophene) P3HT fractions — •Siddharth Joshi1, Souren Grigorian1, Ullrich Pietsch1, Patrick Pingel2, Achmad Zen2, Michael Forster3, and Ullrich Scherf3 — 1Festkörperphysik, Universität Siegen, Walter Flex strasse 3, D-57068, Siegen, Germany. — 2Institut für Physik, Universität Potsdam, Am Neuen Palais 10, D-14469, Potsdam, Germany. — 3Macromolecular Chemistry, Bergische Universität Wuppertal, Gauss-strasse 20, D-42119 Wuppertal, Germany.
GI-XRD in-plane and out-of-plane studies were performed in order to understand the crystallinity, the molecular orientation and the nanoscale morphology of a low-(LMW) and a high molecular weight (HMW) fractions of Poly(3-hexylthiophene) thin films along normal as well as parallel to substrate. Thickness dependence structural ordering has been also investigated for both fractions. At the same time we also correlated thickness dependence of structural ordering with corresponding electrical measurements for both fractions. LMW films are mainly amorphous and contain randomly oriented nano-crystallites with the best match for a monoclinic unit cell. For LMW material, the crystallites were preferentially orientation along the surface normal when the size of crystallites become in the order of film thickness i.e. ~ 20 nm. For HMW fraction we found an increase of lamellar ordering at about 60 K below the melting point of the material. Depending on substrate used (OTS, HMDS or SiO2) one can see a clear difference in the crystal orientation and packing at the interface region.