Enhancing waveguided light extraction in organic LEDs using an ultra-low-index grid.
Improved outcoupling of light into substrate modes of an organic LED (OLED) by an ultra-low index of refraction (n=1.15), porous SiO(2) grid (UltraLIG) fabricated using glancing-angle deposition is demonstrated. Outcoupling into the substrate for electrophosphorescent tris(2-phenylpyridine) iridium [Ir(ppy)(3)]-based OLEDs grown on substrates with the UltraLIG is increased by 48% over a conventional device at a luminance of 100 cd/m(2). With efficient light outcoupling at the substrate-air interface, the UltraLIG devices attain eta(EQE)=22.5% and eta(P)=64 lm/W at their peak efficiencies, a nearly threefold increase over an analogous conventional OLED.
Slootsky
Michael
M
Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA.
Forrest
Stephen R
SR