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Journal of Photonics for Energy • Open Access

Enhancing light extraction in organic light-emitting devices via hemispherical microlens arrays fabricated by soft lithography
Author(s): Sang-Hyun Eom; Edward Wrzesniewski; Jiangeng Xue

Paper Abstract

We demonstrate enhanced light extraction in organic light-emitting devices (OLEDs) by using microlens arrays fabricated by a soft lithography technique. A large-area and close-packed polystyrene (PS) monolayer was formed on the SiO2 substrate using a convective-capillary assembly method, and a polydimethylsiloxane polymer was used to obtain a concave template, from which microlens arrays were fabricated from a photopolymerizable transparent optical adhesive. The microlens contact angle and array fill factor both depend on the size of PS microspheres, and nearly close-packed, hemispherical microlens arrays with microlens contact angle of (85 ± 5 deg) and array fill factor of (85 ± 3)% were obtained with 100-μm PS microspheres. The enhancement in the light-extraction efficiency in OLEDs when such fabricated microlens arrays were attached to the light-emitting surface depends on the contact angle of microlens, device size, and detailed multilayer structure of the OLED. For a large-area (12 × 12 mm) fluorescent OLED with a near close-packed hemispherical microlens array, a maximum enhancement of (70 ± 7)% in the light-extraction efficiency was achieved.

Paper Details

Date Published: 1 January 2011
PDF: 12 pages
J. Photon. Energy. 1(1) 011002 doi: 10.1117/1.3528267
Published in: Journal of Photonics for Energy Volume 1, Issue 1
Show Author Affiliations
Sang-Hyun Eom, Univ. of Florida (United States)
Edward Wrzesniewski, Univ. of Florida (United States)
Jiangeng Xue, Univ. of Florida (United States)

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