Stable driving voltage in exciplex-type OLEDs with a bilayer interface

Organic light-emitting diodes (OLEDs) that produce exciplexes in a bilayer are device structures that can dramatically reduce the turn-on voltage. In this study, we report that this device structure contributes to an impressive improvement in operating lifetime. The lifetime of our OLED is 200 times longer than that of conventional OLEDs, and the voltage does not change after 100 h of operation. The reason for the stable driving voltage is no carrier accumulation inside the device at all by using a displacement current measurement. Analyzing the carrier dynamics in this work will provide a comprehensive solution for OLED degradation.