Lifetime modeling for organic light-emitting diodes: a review and analysis

Organic light-emitting diodes (OLEDs) of all kinds inevitably undergo permanent performance degradation over time, leading to burn-in in the displays made with the OLEDs. To compensate for display burn-in and extend product lifetimes, having a model that can precisely predict OLED degradation is most essential. In this work, we review a few select studies that focused on the physics-based analysis and modeling of OLED degradation. The framework and features of the lifetime models based on the physical mechanisms behind OLED degradation are discussed. In particular, the post-degradation performance of OLEDs is understood in terms of the detrimental effect of degradation-induced defects on the behavior of charges and excitons. Experimental attempts to identify the type and relevant characteristics of the defects are particularly important and thus, are dealt with in this review. Lastly, we discuss the relevant theories and methodologies for measuring the exciton distribution in OLEDs, which is one of the most crucial pieces of information in understanding the device characteristics. We emphasize the limitation of the current lifetime models and what needs to be improved for practical use to achieve a longer lifetime for OLED displays.