Enhancement of outcoupling efficiency of organic light-emitting diodes using a planarized moth-eye structure on glass substrate

To improve optical properties of organic light-emitting diodes (OLEDs), we developed a planarized moth-eye structure by ultraviolet nanoimprint lithography (UV-NIL). The moth-eye pattern was fabricated on a glass substrate by UV-NIL using AMONIL polymer resin. It contains nanoscaled, cone-shaped, periodic pattern arrays with a 250 nm diameter and a 550 nm pitch. The glass substrate with the moth-eye structure exhibited a 1%-2% improvement in transmittance of visible wavelengths, but it requires a planarized layer with high-refractive-index materials. Photosensitive titanium precursor resin annealed by UV was used to improve the current efficiency by up to 26% versus conventional OLEDs.