Lifetime Enhancement Mechanism of Deuteration in Blue OLEDs

The pursuit for brighter and longer-lasting OLED displays is more active than ever in the age of mixed reality. Deuteration is considered a universally effective method for enhancing the lifetime of OLED materials. In this talk, we investigated the cumulative effects of deuteration on the device lifetime of blue OLEDs with emitters based on common polycyclic aromatic hydrocarbons. Their deuterated analogues with incremental deuterium substitutions exhibited similar EL efficiencies but progressively prolonged device lifetimes as a function of deuteration. Through in-situ chemical analysis, we further revealed that the device degradation was initiated from the interfaces between the transport layers and the EML, where the kinetic isotope effect takes effect. By deuterating both host and hole transport materials, up to an eight-fold increase in T90 has been demonstrated in blue OLEDs. We believe that the deuteration strategy is generally applicable to all OLED materials in prolongin g the device lifetime.