Aggregation-induced delayed fluorescent (AIDF) emitters possess both high exciton utilization and excellent device efficiency stability. In this work, two new luminogens CDBP-BP-PXZ and CDBP-BP-DMAC comprising an electron-withdrawing benzoyl group and electron-donating CDBP and PXZ/DMAC moieties are designed, synthesized and systematically investigated. Both luminogens have highly twisted structures to achieve small ΔEST values. They enjoy high thermal and electrochemical stabilities, bipolar carrier transport ability and exhibit typical AIDF characteristics. The non-doped and doped devices using CDBP-BP-PXZ as emitter radiates strongly with high EL efficiencies of up to 15.5%, and 20.8%, respectively. By adopting CDBP-BP-DMAC as emitter, sky-blue emissions with high EL efficiencies of 9.5% and 16.8% are acquired in non-doped and doped devices, respectively. More importantly, both non-doped and doped devices show excellent emission color stability and very small efficiency roll-offs at 1000 cd m−2. These excellent EL performances of CDBP-BP-PXZ and CDBP-BP-DMAC demonstrate their great application potential in OLEDs.
Master student Hao Chen in our group is the first author of this article, and this work has been published on Materials Chemistry Frontiers (DOI: 10.1039/d1qm01625c.).