Synthesis, crystal structure, aggregation-induced emission enhancement and electroluminescence properties of a novel compound containing carbazole and triarylborane groups

A novel compound 9,9'- (4' - (dimesitylboranyl) - [1,1' - biphenyl] - 3,5 - diyl)bis(9H - carbazole) (DB-BCZ) was synthesized by using carbazole as electron-donors and triarylborane as an electron-acceptor. Its structure was adequately characterized by elemental analysis, mass spectrometry, NMR spectroscopy and X-ray crystallography. The thermal stability, photophysical properties and electrochemical properties of DB-BCZ were systematically investigated. The results show that DB-BCZ possesses good thermal stability with T-d of 394 degrees C and aggregation-induced emission enhancement (AIEE) feature. The single structure of the crystal presents a twisted propeller configuration, belonging to monoclinic system with space group symbol Cc. The packing structure of the crystal shows that there are hydrogen bonds (C - H center dot center dot center dot pi . and C - H center dot center dot center dot H) formed between adjacent molecules, and there is no typical pi -pi interaction between the aromatic rings, which may be the main reason for the formation of AIEE. Furthermore, non-doped OLED employing DB-BCZ as emitting layer displays bluish-violet emission, and exhibits a turn-on voltage of 5.6 V, a maximum luminance of 5374 cd m(-2), a maximum current efficiency of 2.26 cd( )A(-1) and a maximum power efficiency of 0.96 lm W-1. Meanwhile, the device is slow in efficiency roll-off. The results demonstrate that DB-BCZ is a promising candidate for OLEDs. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

A novel compound DB-BCZ was synthesized using carbazole as electron donors and triarylborane as an electron acceptor. It exhibits good thermal stability and AIEE feature, with a twisted propeller configuration in the crystal structure. The non-doped OLED with DB-BCZ as the emitting layer shows promising performance in terms of efficiency and stability.