Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 46: Poster: Molecular Films - Photovoltaics, Electronics and Morphology
O 46.1: Poster
Dienstag, 13. März 2018, 18:15–20:30, Poster A
Control of Polymorphic Phases of an Anilino Squaraine by Organic Molecular Beam Deposition — Tobias Breuer1, Frank Balzer2, Matthias Schulz3, Arne Lützen3, •Manuela Schiek4, and Gregor Witte1 — 1University of Marburg, D — 2University of Southern Denmark, Sonderborg, DK — 3University of Bonn, D — 4University of Oldenburg, D
Squaraines are small molecular quadrupolar donor-acceptor-donor (D-A-D) chromophores absorbing in the red spectral range considered for application as photovoltaic materials [1, 2]. A prototypical anilino squaraine with branched alkyl side chains (SQIB) crystallizes at least into two polymorphic bulk structures. In spin-casted thin films these two phases emerge with a strongly preferred out-of-plane and rather random in-plane orientation upon thermal post-annealing directed by the annealing temperature [3]. Now we investigate the surface induced growth of thermally vapor deposited SQIB on varying dielectric and conductive substrates and correlate the observed polymorphs to the substrate properties. We approach a complete picture of molecular orientation relative to the substrate geometry for instance by X-ray diffraction and polarized light microscopy. [1] Appl. Phys. Lett. 111 (2017) 183502. [2] Langmuir 32 (2016) 8533. [3] Cryst. Growth Des. (2017) DOI: 10.1021/acs.cgd.7b01131.