Department of Chemistry
A star-shaped bipolar host material based on carbazole and dimesitylboron moieties for fabrication of highly efficient red, green and blue electrophosphorescent devices
A new bipolar host material based on carbazole and dimesitylboron moieties, 3,6-bis(dimesitylboryl)-9-(4-(dimesitylboryl)phenyl) carbazole (BDDPC), has been successfully synthesised and characterised by elemental analysis, nuclear magnetic resonance spectroscopy, mass spectrometry and thermogravimetric analysis. The electrochemical and photophysical properties of BDDPC are studied by both experimental and theoretical methods. BDDPC exhibits excellent thermal stability (Td = 234 °C), electrochemical stability, high fluorescence quantum yield (0.95) and high triplet energy (2.83 eV). A red phosphorescent organic light-emitting diode (PhOLED) device comprising BDDPC as the host material and Os(bpftz)2(PPh2Me)2 as the dopant is fabricated and displays promising electrophosphorescence properties with a turn-on voltage of 3.0 V, a maximum brightness of 12337 cd m-2 and a maximum current efficiency of 11.04 cd A-1. Similarly, BDDPC is used to fabricate a green PhOLED device with Ir(ppy) 2(acac) as the dopant, possessing a turn-on voltage of 2.5 V, a maximum brightness of 26473 cd m-2 and a maximum current efficiency of 38.60 cd A-1. Furthermore, a blue PhOLED device with BDDPC as the host material and FIrpic as the dopant is fabricated with a turn-on voltage of 3.0 V, a maximum brightness of 7622 cd m-2 and a maximum current efficiency of 7.39 cd A-1. It is anticipated that BDDPC has great potential in manufacturing PhOLED devices for display or lighting applications. © 2014 The Royal Society of Chemistry.
Source Publication Title
Journal of Materials Chemistry. C
Royal Society of Chemistry
Shi, Heping, Dehua Xin, Xiuqing Dong, Jian-Xin Dai, Xiaohuan Wu, Yanqin Miao, Li Fang, Hua Wang, and Martin M. F. Choi. "A star-shaped bipolar host material based on carbazole and dimesitylboron moieties for fabrication of highly efficient red, green and blue electrophosphorescent devices." Journal of Materials Chemistry. C 2.12 (2014): 2160-2168.