Simple Phenanthroimidazole/Carbazole Hybrid Bipolar Host Materials for Highly Efficient Green and Yellow Phosphorescent Organic Light-Emitting Diodes

TLDR: By conjugating carbazole moiety to the different positions of the rigid skeleton 1,2-diphenyl-1H-phenanthro[9,10-d]imidazole, a series of hybrid bipolar phosphorescent hosts was synthesized, and their photophysical properties were investigated.

Abstract: By conjugating carbazole moiety to the different positions of the rigid skeleton 1,2-diphenyl-1H-phenanthro[9,10-d]imidazole, a series of hybrid bipolar phosphorescent hosts was synthesized, and their photophysical properties were investigated. The introduction of a rigid phenanthroimidazole moiety greatly improves their morphological stability, with high decomposition temperatures (Td) and high glass transition temperatures (Tg) in the range of 394–417 and 113–243 °C, respectively. The highly efficient green and orange phosphorescent organic light-emitting diodes (PhOLEDs) have been achieved by employing these compounds as the phosphorescent hosts. For the device of ITO/MoO3 (10 nm)/NPB (80 nm)/TCTA (5 nm)/mPhBINCP:9 wt % Ir(ppy)3 (20 nm)/TmPyPB (45 nm)/LiF (1 nm)/Al (100 nm), a maximum luminous efficiency (ηc,max) of 77.6 cd/A, maximum power efficiency (ηp,max) of 80.3 lm/W, and maximum external quantum efficiency (ηEQE,max) of 21% were obtained. Furthermore, these hosts are also applicable for the oran...