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Proceedings Paper

Development and characterization of adjustable refractive index scattering epoxy acrylate polymer layers
Author(s): Thomas Eiselt; Jan Preinfalk; Uwe Gleißner; Uli Lemmer; Thomas Hanemann
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Paper Abstract

This work presents different polymer diffusing films for optical components. In optical applications it is sometimes important to have a film with an adjusted refractive index, scattering properties and a low surface roughness. These diffusing films can be used to increase the efficiency of optical components like organic light emitting diodes (OLEDs). In this study three different epoxy acrylate mixtures containing Syntholux 291 EA, bisphenol a glycerolate dimethacrylate, Sartomer SR 348 L are characterized and optimized with different additives. The adjustable refractive index of the material is achieved with a chemical doping by 9-vinylcarbazole. Titanium nanoparticles in the mixtures generate light scattering and increase the refractive index additionally. To prevent sedimentation and agglomeration of these nanoparticles, a stabilization agent [2-(2-methoxyethoxy)ethoxy]acetic acid is added to the mixture. Other ingredients are a UV-starter and thermal starter for the radical polymerization. A high power stirrer (ultraturrax) is used to mix and disperse all chemical substances together to a homogenous mixture. The viscosity behavior of the mixtures is an important property for the selection of the production method and gets characterized.

After the mixing, the monomer mixture is applied on glass substrates by blade coating or screen printing.

To initiate the chain growing (polymerization) the produced films are irradiated for 10 minutes long with UV light (UV LED Spot Hönle, 405 nm). After this step a final post bake from the layers in the oven (150°C, 30 min.) is operated.

Light transmission measurements (UV-Vis) of the polymer matrix and roughness measurements complement the characterization.

Paper Details

Date Published: 23 September 2016
PDF: 7 pages
Proc. SPIE 9939, Light Manipulating Organic Materials and Devices III, 99390Q (23 September 2016); doi: 10.1117/12.2235905
Show Author Affiliations
Thomas Eiselt, Karlsruher Institut für Technologie (Germany)
Albert-Ludwigs-Univ. (Germany)
Jan Preinfalk, Karlsruher Institut für Technologie (Germany)
Uwe Gleißner, Albert-Ludwigs-Univ. (Germany)
Uli Lemmer, Karlsruher Institut für Technologie (Germany)
Thomas Hanemann, Karlsruher Institut für Technologie (Germany)
Albert-Ludwigs-Univ. (Germany)

Published in SPIE Proceedings Vol. 9939:
Light Manipulating Organic Materials and Devices III
Joy E. Haley; Jon A. Schuller; Manfred Eich; Jean-Michel Nunzi, Editor(s)

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