Enhancing light extraction in organic light-emitting devices via hemispherical microlens arrays fabricated by soft lithography

Sang-Hyun Eom; Edward Wrzesniewski III; Jiangeng Xue

doi:10.1117/1.3528267

1 January 2011 Enhancing light extraction in organic light-emitting devices via hemispherical microlens arrays fabricated by soft lithography

Sang-Hyun Eom, Edward Wrzesniewski III, Jiangeng Xue

Author Affiliations +

Journal of Photonics for Energy, Vol. 1, Issue 1, 011002 (January 2011). https://doi.org/10.1117/1.3528267

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.

Citation Download Citation

Sang-Hyun Eom, Edward Wrzesniewski III, and Jiangeng Xue "Enhancing light extraction in organic light-emitting devices via hemispherical microlens arrays fabricated by soft lithography," Journal of Photonics for Energy 1(1), 011002 (1 January 2011). https://doi.org/10.1117/1.3528267

Published: 1 January 2011

ACCESS THE FULL ARTICLE

JOURNAL ARTICLE
12 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY