Chemistry Letters, Vol.43, No.12, 1935-1936, 2014
A Donor-Acceptor-type Host Material for Solution-processed Phosphorescent Organic Light-emitting Devices Showing High Efficiency
The solution-processable host material, 3,3'-{bis(9-phenylcarbazol-3-yl)]benzophenone (BCzBP), containing donor-type phenylcarbazole units and an acceptor-type benzophenone unit was synthesized. BCzBP showed a high excited triplet energy level and a high photoluminescence quantum efficiency with tris[2-(4-tolyl)pyridine]iridium ([Ir(mppy)3]) as a dopant, and a high glass-transition temperature. Solution-processed green phosphorescent OLEDs were fabricated with BCzBP. The device with BCzBP as a host showed comparable efficiencies to those of the corresponding device with 4,4'-bis(N-carbazolyl)biphenyl (CBP) as a host. At the same current density, the device with BCzBP showed a longer device lifetime than that with CBP, due to the high thermal stability and the bipolar nature of the host compound, BCzBP.