title: Efficiency enhancement of flexible organic light-emitting devices by using antireflection nanopillars.
abstract: We present an antireflection structure consisted of irregular nanopillars to increase light extraction efficiency of flexible organic light-emitting devices. The nanopillars were made by imprinting the anodized aluminum oxide on polycarbonate substrates. The thermal viscosity effect formed the nanopillars with tapered shapes. Such nanopillars show excellent antireflection properties for a wide range of incident angles and wavelengths. The normal transmittance was improved from 85.5% to 95.9% for 150-nm-height nanopillars. The transmittance was greatly improved from 52.8% to 89.1% at 60° incident angle. With this antireflection structure, the device efficiency was improved 69% as compared to devices with flat substrates. Due to wide-angle antireflection, the image contrast ratio was also significantly improved.
authors.affiliation: Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan.
authors.forename: Yu-Hsuan
authors.initials: YH
authors.lastname: Ho
authors.forename: Chung-Chun
authors.initials: CC
authors.lastname: Liu
authors.forename: Shun-Wei
authors.initials: SW
authors.lastname: Liu
authors.forename: Hsun
authors.initials: H
authors.lastname: Liang
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Chu
authors.forename: Pei-Kuen
authors.initials: PK
authors.lastname: Wei