Berlin 2001 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 18: Poster: Polymer Blends, Heterogeneous Systems, Colloids and Nanoparticles, Interfaces, Polyelectrolytes

CPP 18.37: Poster

Mittwoch, 4. April 2001, 12:30–15:00, AT1

Optimization of a Multifunctional ATOP Chromophore for High-Refractive-Index Modulation in Photorefractive Materials — •Francisco Gallego-Gomez¹, Erwin Mecher¹, Klaus Meerholz¹, Sheng Yao², and Frank Wuerthner² — ¹Physical Chemistry Department, University of Munich, Butenandtstr. 11, 81377 Munich — ²Department of Organic Chemistry II, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm

This paper reports about the optimization of Amino-thienyl-dioxocyano-pyridine (ATOP) chromophores towards a multifunctional amorphous material with unprecedented photorefractive performance. The important materials-related properties such as compatibility with the photoconducting poly(N-vinylcarbazole) (PVK) host matrix, low melting point, low glass-transition temperature, and film-forming capabilities were optimized by variation of four different alkyl substituents attached to the ATOP core. A morphologically stable PVK-based composite containing 40 photorefractive response characterized by a refractive index modulation of ca. 0.007 and a gain coefficient of about 180 1/cm at moderate electrical field strength of E = 35 V/micron. Even larger effects were observed with thin amorphous films consisting of the pure glass-forming dye ATOP-4 and 1 (TNFM). This material showed complete internal diffraction at a field strength of only E = 10 V/micron and the index modulation reached 0.01 at only E = 22 V/micron without addition of any specific photoconductor.