Driving Duty Ratio Dependence of Lifetime of Tris(8-hydroxy-quinolinate)aluminum-Based Organic Light-Emitting Diodes

The driving duty ratio dependence of the luminance lifetime of various tris(8-hydroxy-quinolinate)aluminum-based organic light-emitting devices (OLEDs) was investigated. High-duty-ratio driven devices with low mean operational voltage had a long lifetime in comparison to DC-driven devices. This indicates voltage-mode degradation was suppressed by high-duty-ratio driving. The long lifetime effected by high-duty-ratio driving became increasingly small in the range of large operational mean current because of accelerated current-mode degradation. The development of high-efficiency OLEDs, therefore, is of prime importance not only to achieve low power consumption but also to obtain long-lifetime OLEDs by high-duty-ratio driving.