Back Migration Based Long Lifetime Approach for Organic Light‐Emitting Diode

Lifetime is one critical reliability issue in electronics, especially in organic devices including organic light emitting diodes (OLEDs), solar cells, thin film batteries, thin film transistors, and memories, etc. Many causes that contribute to device failures have been found out. So far, several methods for improvement in the device lifetime have been proposed, albeit effective approaches are still under developing and the ideal will be the one that enables cost‐effective fabrication with ease of processing. Here an easy‐to‐apply method based on the back migration to improve the lifetime of OLED as well as LED devices are presented. That is done by simply applying a reverse bias voltage with an appropriate magnitude. For example, lifetime of a studied white OLED device at 9500 cd m−2 can be increased from 288 to 685 h, an increment of 137%, as a reverse bias of 10 V is applied to the pristine device for 2 h. It can be further increased to 857 h, an increment of 197%, as the reverse bias is kept for 4 h. The lifetime can still be improved for non‐pristine devices. Reverse poling causes back‐diffusion of electrode atoms and OLED materials, and reduces the growth of spikes on both electrodes. White OLED device lifetime at 9500 cd m−2 is increased from 288 to 857 h, an increment of 197%, by applying a 10 V reverse bias for 4 h.