Highly efficient, charge balanced blue phosphorescent OLEDs employing wide band gap host with p-i-n architecture

In this study we report the use of a wide band gap host host p-bis (triphenylsilyly) benzene (UGH2) for Iridium (III) bis [(4, 6-difluorophenyl)-pyridinato-N, C2´] picolinate (FIrpic) based devices. The wide band gap host serves to confine the charge carriers in the emitting layer. Also the high triplet energy of the host efficiently confines all the excitons on the dopant molecules. A systematic effort is made to enhance the performance of blue phosphorescent organic light emitting diodes using the UGH2 host. The device performance of the intrinsic device was further enhanced by incorporation of a p-i-n architecture to tune the charge balance in the device.