Outcoupling Efficiency Analysis of OLEDs Fabricated on a Wrinkled Substrate

Enhancement of outcoupling efficiency of OLEDs by using a buckled or wrinkled substrate has been recently reported by several groups, while an optical analysis for understanding the coupling between various modes in OLED devices has not been conducted. For various wrinkle shape, FDTD simulation was conducted to find the external quantum efficiency improved by the coupling into a radiation mode, and the power fraction of various modes existing in the OLED device was examined. Consequently, we found that the coupling between TE mode and surface plasmon mode was critically affecting the fraction of outcoupled mode. For confirming the simulation results with an experiment, the wrinkled OLED device was fabricated by incorporating a novel UV curable liquid prepolymer material. The experimental result corresponded well to the prediction from FDTD analysis.