A low‐cost facile synthesis of solution processable N‐phenylcarbazole/triazine hybrid host for orange TADF OLEDs
Xiang-Hua Zhao, Rui-Rui Li, Ya-Nan Han, Yue Li, Guo-Dong Zou, Guohua Xie, Xin-Wen Zhang, Ming-Li Sun, Ling-Hai Xie- Materials Chemistry
- Electrical and Electronic Engineering
- Surfaces, Coatings and Films
- Surfaces and Interfaces
- Condensed Matter Physics
- Electronic, Optical and Magnetic Materials
An N‐phenylcarbazole/triazine hybrid of 2,4,6‐tris(9‐phenyl‐9H‐carbazol‐3‐yl)‐1,3,5‐triazine (TPhCz‐Trz) was successfully synthesized using cheap raw materials via facile synthesis method with a high yield of 60.9%. Good thermal (Td, 284 oC) and morphological stability were 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) was 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 (tBu‐ Cz‐DBA) with the maximum external quantum efficiency (EQE) of 14.0%. The large bathochromic‐shift is probably induced by the polarity of the host compared to the emission peak 542 nm of tBuCz‐DBA based green TADF device. This indicates high performance of devices with different color would be achieved through optimizing molecular structure of the host and device framework using tBuCz‐DBA as emitter.
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