A Low-Cost Facile Synthesis of Solution-Processable N-Phenylcarbazole/Triazine Hybrid Host for Orange Thermally-Activated Delayed Fluorescent Organic Light-Emitting Diodes

An N-phenylcarbazole/triazine hybrid of 2,4,6-tris(9-phenyl-9H-carbazol-3-yl)-1,3,5-triazine (TPhCz-Trz) is successfully synthesized using cheap raw materials via facile synthesis method with a high yield of 60.9%. Good thermal (Td, 284 degrees C) and morphological stability are realized due to its rigid structure and three-dimensional steric hindrance. The high triplet energy level of 2.88 eV for the host is very important to inhibit the energy reverse from guest to host. Surprisingly, orange thermally-activated delayed fluorescent (TADF) organic light-emitting diodes (OLEDs) are achieved by using excellent green emitter 9,10-bis(4-(3,6-ditertbutyl-9H-carbazol-9-yl)-2,6-dimethyl-phenyl)-9,10-diboraanth-racene (tBuCzDBA) with the maximum external quantum efficiency of 14.0%. The large bathochromic-shift is probably induced by the polarity of the host compared to the emission peak of 542 nm of tBuCzDBA-based green TADF device. This indicates high performance of devices with different colors would be achieved through optimizing molecular structure of the host and device framework using tBuCzDBA as emitter. A low-cost facile synthesis of solution-processable N-phenylcarbazole/triazine hybrid host for orange thermally-activated delayed fluorescent organic light-emitting diodes (TADF OLEDs). An orange TADF OLEDs is reported using green material tBuCzDBA as emitter for the first time with the maximum external quantum efficiency of 14.0%, which is induced by the polarity of the host.image (c) 2024 WILEY-VCH GmbH