High efficiency in solution processed blue phosphorescent organic light-emitting diodes using an alcohol soluble emitting layer

High efficiency solution processed blue and deep blue phosphorescent organic light-emitting diodes (PHOLEDs) were developed using an alcohol soluble 2,7-bis(diphenylphosphoryl)-9-phenyl-9H-carbazole (PPO27) as the host material for the emitting layer. Iridium(III) bis(4,6-(di-fluorophenyl)-pyridinato-N,C′) picolinate (FIrpic) and iridium(III) bis((3,5-difluoro-4-cyanophenyl)pyridinato-N,C′) picolinate (FCNIrpic) were doped into the PPO27 host using 2-propanol as the solvent for the emitting layer. The alcohol soluble PPO27:FIrpic and PPO27:FCNIrpic emitting layers could form an orthogonal film with an organic soluble hole transport layer and high quantum efficiency of 14.6% and 13.4% was achieved in the PPO27:FIrpic and PPO27:FCNIrpic devices, respectively. Sky blue color coordinate of (0.15, 0.36) was obtained in the PPO27:FIrpic device, while blue shifted color coordinate of (0.15, 0.26) was realized in the PPO27:FCNIrpic device.

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► High efficiency solution processed blue organic light emitting diodes.
► Multilayer structure formation by alcohol soluble emitting layer.
► Orthogonal film formation by solubility difference between organic layers.