Blue Aggregation-Induced Delayed Fluorescence Materials with 5,10-Dihydrodibenzo[<i>b</i>,<i>e</i>][1,4]azasiline as Donor

Three blue-emitting materials were developed using 10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasiline (DPDBA) and carbazole derivative as donors, and benzophenone as acceptor to construct donor-acceptor-donor (D-A-D') type molecules, and their thermal stability, electrochemical properties, single crystal structure, photophysical properties and electroluminescence properties were systematically studied. And they have small singlet-triplet energy splitting and microsecond-scale delayed lifetimes, showing obvious aggregation-induced delayed fluorescence (AIDF) characteristics. As light-emitting layers of organic light-emitting diodes (OLEDs), the electroluminescence peaks of these compounds are in the range of 474～476 nm, and the maximum external quantum efficiency (EQE) can reach 14.8%. Additionally, these compounds exhibit good bipolar carrier transport performance, and can be used as host materials for phosphorescent devices. The maximum EQEs of green and yellow phosphorescent OLEDs are 25.5% and 21.2%, respectively, and the efficiency roll-off at 1000 cd•m^－2 is very small. These results indicate that these AIDF compounds can be used not only as luminescent materials but also as host materials for the preparation of high-performance.