Triplet-induced degradation: An important consideration in the design of solution-processed hole injection materials for organic light-emitting devices

Abstract

Solution-processed organic light-emitting devices (OLEDs) still require improvements in their operational lifetime in order for them to become commercially viable. One factor that limits the lifetime of these devices is the instability of the hole injection layer (HIL). Therefore, understanding its degradation mechanism is crucial for the development of more stable solution-processed OLEDs. In this work, we use an archetypal fluorescent OLED in conjunction with an experimental solution-processed HIL in order to elucidate the degradation mechanism in these HILs. Our studies show that degradation is caused by triplet excitons. This new triplet-induced hole injection degradation is expected to be a common phenomenon in OLEDs, and therefore should have important implications for the design of stable HILs.