Carrier dynamics and degradation behavior in exciplex upconversion-type organic light-emitting diodes

Abstract Organic light-emitting diodes (OLEDs) have attracted considerable attention for display and lighting applications. However, improving device stability and operational lifetime remains a major issue. In this study, exciplex upconversion-type OLEDs (ExUC-OLEDs) utilizing a donor/acceptor interface were investigated to achieve low-voltage operation and enhanced device stability. Compared with conventional OLEDs, the ExUC-OLED exhibited superior voltage stability and a 35 times longer operational lifetime. Displacement current measurements confirmed that charge accumulation was effectively suppressed even after long-term operation and ideal carrier recombination at the interface was achieved. Analysis focusing on carrier dynamics provides new insights into the degradation processes of OLEDs.