P‐182: A Numerical Analysis of Current Efficiency Hump at Low Grey in the OLED Devices

The hump behavior of current efficiency in OLEDs(Organic Light Emitting Diodes) were often observed at the low voltage under certain charge balance condition. The color non‐linearity with image sticking in the low voltage level was found to be well correlated with the existence of hump phenomena. In this paper, we explained the mechanism of hump is trade‐off between Langevin recombination and SRH(Schokley‐Reed‐Hall) recombination, and found out SRH recombination could be mainly controlled by EML(Emitting Layer)/ETL(Electron Transport Layer) interface barrier using OLED device simulation. Additionally we could suggest the conditions that reduce the hump at the low grey region to improve the performance of OLED device. Finally the color non‐linearity of OLED device was improved by elimination of hump behavior.