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SYOO: Organic Optoelectronics and Photonics
SYOO 6: Poster
SYOO 6.42: Poster
Montag, 7. März 2005, 18:00–20:00, Poster TU A
Molecular structure and electronic properties of poly(3-hexylthiophene)s — •Achmad Zen1, Marina Saphiannikova1, Dieter Neher1, Joerg Grenzer1, Udom Asawapirom2, and Ullrich Scherf2 — 1Department of Physics, University of Potsdam, Am Neuen Palais 10, 14469 Potsdam, Germany — 2Macromolecular Chemistry, University of Wuppertal, Gauss Str.20, 42097 Wuppertal, Germany
It was shown recently that decreasing the molecular weight (Mw) of poly(3-hexylthiophenes)s (P3HT) leads to a drastic reduction of the field effect mobility in thin layers.[1,2] Here, we present the results of structural studies of P3HT fractions of different molecular weight, in relation with their electronic properties. Using X-ray grazing incidence diffraction (GID), we found that films of the highest Mw fraction are amorphous at the surface, but slightly crystalline in the bulk, while films with the lowest Mw P3HT are highly polycrystalline throughout the sample. The data also suggest that the packing of the low molecular weight P3HT differs from that of the high Mw fraction. We conclude that the backbone planarity and packing rather than grain boundaries controls the field effect mobility in these polymer layers.
[1]. R. J. Kline, M. D. McGehee, E. N. Kdnikova, J. Liu, and J. M. J. Frechet, Adv. Mater. 15 (2003) 1519. [2]. A. Zen, J. Pflaum, S. Hirschmann, W. Zhuang, F. Jaiser, U. Asawapirom, J. P. Rabe, U. Scherf, and D. Neher, Adv. Funct. Mater. 14 (2004) 757.