OLED light extraction with corrugated substrate and hemispherical lens (Conference Presentation)

While the internal quantum efficiency of an OLED can reach 100%, its external quantum efficiency (EQE) is limited to 30% because of light trapped in waveguided mode, SPP mode and substrate mode. In this study, we achieve more than 2X enhancement in EQE by using a corrugated substrate and a hemispherical lens. Polarized angle-resolved electroluminescence spectroscopy is used to analyzed the EL data, and the results are compared with optical simulation. We find the efficiency enhancement mainly comes from the diffraction of the SPP mode towards air mode due to the corrugated substrate, and the hemispherical lens assists the light extraction by extending the air cone into the substrate mode.