Corrugated organic light-emitting diodes to effectively extract internal modes

Authors :: Tien-Lung Chiu
Xiaofeng He
Chi-Feng Lin
Mao-Kuo Wei
Jiu-Haw Lee
Jiahui Wang
Haowen Liang
Jiangning Wu
Hao-Chun Hsu
Source :: Optics Express. 27:A372
Publication Year :: 2019
Publisher :: The Optical Society, 2019.
Abstract: We report a corrugated structure to effectively extract the surface plasmon polaritons (SPP) and waveguiding modes in organic light-emitting diodes (OLEDs). This structure is formed by nano-imprint of blazed gratings. To study the optimum extraction condition in terms of grating pitches, we compare the light extraction efficiency of corrugated OLEDs with three kinds of pitches, showing a 42.00% external quantum efficiency (EQE) enhancement ratio with this internal structure. Due to the transfer of SPP and waveguiding modes into substrate mode, the EQE enhancement ratio can be further pushed to 103.02% by attaching a macrolens. The simulation verifies the experimental results and shows the extraction mechanism of the corrugated structure towards transverse electric (TE) and transverse magnetic (TM) waves. We foresee that this method is able to enhance the optical efficiency of devices for both mass-production OLED lighting and display in a cost-effective way.