Highly Efficient Bipolar Host Materials with lndenocarbazole and Pyrimidine Moieties for Phosphorescent Green Light-Emitting Diodes

In this paper, we report bipolar host materials, 6-(2,6-diphenyl-pyrimidin-4-yl)-12,12-dimethyl-6,12,12'-trihydroindeno[1,2-b]carbazole (DPICz1) and 6-(2,6-diphenyl-pyrimidin-4-yl)-12,12-dimethyl-6,12,12'-trihydroindeno[1,2-b]carbazole (DPICz2), with indenocarbazole moiety as a hole-transporting unit and pyrimidine moiety as an electron-transporting unit for highly efficient green phosphorescent organic light-emitting diodes. The synthesized materials show excellent electro-optical properties. Similarly, it also exhibits outstanding thermal and morphological stability due to high glass transition temperature (T-g) of 161 degrees C and decomposition temperature (T-d) of 327401 degrees C. Fabricated green phosphorescent organic light-emitting diode shows excellent current and power efficiency of 77.8 cd/A and 62.8 lm/W as well as almost ideal external quantum efficiency of 22.3% at the brightness of 1000 cd/m2.