Cumulative lifetime enhancement effect of deuteration in blue organic light‐emitting diodes

Abstract This research investigates the impact of deuteration on the operational lifetime of blue organic light‐emitting diodes (OLEDs). Our study focuses on the kinetic isotope effect (KIE) and how it enhances device lifetime. Specifically, we examine the effects of deuteration on OLEDs with emitters based on common polycyclic aromatic hydrocarbons by deuterating anthracene‐based host materials. Our findings show that the deuterated analogues with incremental deuterium substitutions exhibit similar electroluminescence (EL) performances but progressively prolonged device lifetimes as a function of deuteration, indicating a cumulative enhancement effect. We observed a twofold increase in device lifetime with partial deuterium substitutions, while highly deuterated hosts realized up to a fourfold improvement. Furthermore, we found that device degradation is initiated from the interface of the hole transport layer (HTL) and emitting layer (ETL), and deuteration can mitigate the degraded reactions in the devices, thereby improving operational stability. These results provide insight into how deuteration can increase the operational lifetime of OLEDs, which has important implications for developing more efficient and durable OLED materials.