Enhancement of normally directed light outcoupling from organic light-emitting diodes using nanoimprinted low-refractive-index layer

Abstract

The authors have demonstrated increased light outcoupling from organic light-emitting diodes (OLEDs) based on nanoimprinted amorphous fluoropolymer, poly[perfluoro(4-vinyloxy-l-butene)] (PPFVB). Because PPFVB has a low refractive index and a high transmittance over wide wavelength range, the first-order Bragg diffracted light shows high directionality and decreased waveguide absorption. These characteristics provide an advantage for small- or medium-sized OLEDs, which are mainly viewed from the normal direction.

Tailored Highly Transparent Composite Hole‐Injection Layer Consisting of Pedot:PSS and SiO2 Nanoparticles for Efficient Polymer Light‐Emitting Diodes

“…[ 14 ] Bragg-gratings near the anode or the cathode have been successfully utilized to extract waveguide modes and surface plasmon polaritons. [15][16][17][18][19] Furthermore, lowindex grids, [ 20 , 21 ] and nanoparticles inside the organic layers have also been proved to couple out photons from the device. [ 22 ] The composite organic/inorganic HTLs presented here are suitable for tailoring the OLED stack design as well as for integrating nanoparticles for improved outcoupling via scattering.…”

Perfluoropolymer Surface for Shock‐free Homeotropic Alignment of Smectic Liquid Crystals

“…[13,14] It also has high solubility in perfluorinated solvents and is highly resistant to chemical and thermal stimuli. These properties make deposition of indium tin oxide (ITO) and nanoimprint lithography (NIL) possible for photonic application in organic light-emitting diodes (OLEDs), [15] lasing, [16] and biological applications. [17] In this Communication we propose and demonstrate a new application of PPFVB as a VA layer for smectic LCs.…”

Highly efficient inverted polymer light-emitting diodes using surface modifications of ZnO layer

“…One method of enhancing the out-coupling efficiency is to use a high-refractiveindex glass substrate and a hemisphere microlens thereon [16][17][18] . Moreover, a Bragg diffraction grating (BDG), a low-index grid and an internal scattering structure of the organic layer have been introduced in these devices for the light extraction of the indium tin oxide (ITO)/organic WG mode [19][20][21][22][23][24] . However, BDGs fabricated using the electron-beam lithography 19 , nanoimprinting 20 and holographic methods [21][22][23] incur the high costs and require complex techniques.…”

“…Moreover, a Bragg diffraction grating (BDG), a low-index grid and an internal scattering structure of the organic layer have been introduced in these devices for the light extraction of the indium tin oxide (ITO)/organic WG mode [19][20][21][22][23][24] . However, BDGs fabricated using the electron-beam lithography 19 , nanoimprinting 20 and holographic methods [21][22][23] incur the high costs and require complex techniques. In addition, it is difficult to extract at broad range of light emission using BDGs with regular periodic structures for white OLEDs because such a BDG extracts specific emission wavelengths in accordance with Bragg's law, depending on the specific grating period and angle.…”