Time-resolved fluorescence studies of degradation in tris(8-hydroxyquinoline) aluminum (AlQ3)-based organic light emitting devices (OLEDs)

Device stability has been a major concern for organic light emitting devices (OLEDs). Recently, we found that the injection of holes in tris(8-hydroxyquinoline) aluminum (AlQ3), a widely used organic electroluminescent material, is the main factor responsible for degradation in OLEDs based on this material. The photoluminescence (PL) quantum efficiency of AlQ3 has been found to decrease as a result of predominantly hole current flow. Studies using time-resolved fluorescence measurements show that the decrease in the PL quantum efficiency is associated with a decrease in the lifetime of the AlQ3 excited states, thus revealing the nature of the degradation products as luminescence quenchers.