Bis(1-phenyl-1H-benzo[d]imidazole)phenylphosphine oxide interlayer for effective hole blocking in efficient phosphorescent organic light emitting diodes based on widely used charge transporting layers

- PHOLEDs based on Ir(ppy)3 emit at 512 nm with CIE color coordinates of (0.30, 0.59).
- BIPO with deep HOMO and higher electron transport property effectively blocks the holes.
- ETL type BIPO interlayer improves the charge balance in the EML of the device.
- PHOLED using NPB, TcTa, BIPO HBL, and Alq3 shows the maximum luminance of 75,080 cd/m2.
- It exhibits the higher device efficiencies of 44.37 cd/A, 14.42% and 14.67 lm/W.