Hamburg 2001 – scientific programme
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SYOF: Organische Festkörper
SYOF 5: Poster Session
SYOF 5.22: Poster
Tuesday, March 27, 2001, 17:00–19:00, Aula S3
Design of molecular interactions in organic semiconductors to control the conduction type and emission yield of thin films — •D. Schlettwein1, H. Graaf1,2, W. Michaelis1, N. Jaeger1, D. Wöhrle1, T. Unold3, G.H. Bauer3, and H. Yanagi4 — 1Dept. of Chemistry, Univ. of Bremen, Germany — 2present adress: Institute for Molecular Science, Okazaki, Japan — 3Dept. of Physics, Univ. of Oldenburg, Germany — 4Faculty of Engineering, Kobe University, Japan
Perylene- and phthalocyanine- pigment molecules were systematically modified and consequences were studied for their solid state properties. Thin films (1- 150 nm) were prepared by physical vapor deposition. Intermolecular coupling was probed by optical measurements in absorption and emission as well as by electrical measurements.
n- type conduction was established by use of electron- withdrawing substituents. Different interactions among the molecules and with the substrate surfaces allowed to prepare either crystalline or amorphous films. Crystalline films were characterized by strong chromophore coupling leading to characteristic splitting, well- defined shifts of optical absorption bands and emission mainly from excimeric species whereas the chromophore coupling in the amorphous films was suppressed sufficiently to provide a significantly increased photoemission yield from uncoupled monomeric states.