High and Balanced Bipolar-Transporting Deep-Blue HLCT Material for Efficient Monochrome and White OLEDs based on a Simple Phenanthroimidazole-Dibenzothiophene Derivative

The irreconcilable contradiction between wide bandgap and charge carriers injection/transport in deep-blue organic electroluminescence materials is one of the largest bottlenecks restricting the development of organic light-emitting diodes (OLEDs). Here, a multifunctional deep-blue hybridized local and charge-transfer material containing a phenanthroimidazole-dibenzothiophene derivative that can act as an emitter as well as a host for phosphorescent OLEDs is reported. Owing to its high and balanced bipolar-transporting ability, remarkable fluorescence efficiency, and suitable triplet energy level, the deep-blue device with it as a neat emitter provides an external quantum efficiency (EQE) of 6.68%, while yellow and red phosphorescent OLEDs offer the EQEs of 25.35% and 22.19%, respectively. All of them exhibit low-efficiency roll-off characteristics. What's more amazing is that the fluorescent/phosphorescent hybrid white OLEDs achieve high power efficiencies and EQEs over 95.9 lm W-1 and 26.8%, and the values are still higher than 77.7 lm W-1 and 25.6% at the high luminance of 1000 cd m-2. A deep-blue hybridized local and charge-transfer emitter PPIS can act as an efficient emitter and host for phosphorescent organic light-emitting diodes (OLEDs), realizing the external quantum efficiencies of 6.68%, 19.32%, 25.35%, and 22.19% in blue/green/yellow/red monochrome OLEDs and high efficiencies of over 95.9 lm W-1 and 26.8% in hybrid white OLEDs.image