Efficiency improvement of solution processed blue phosphorescent devices using high triplet energy electron transport layer

摘要

High efficiency solution processed blue phosphorescent organic light emitting diodes (PHOLEDs) were developed using a high triplet energy exciton blocking layer. A spirobifluorene-based phosphine oxide compound was used as the exciton blocking layer for poly(N -vinylcarbazole) (PVK):iridium(III) bis[4,6-(difluorophenyl)-pyridinato- N, C′] picolinate (FIrpic) emitting layer. A high quantum efficiency of 12.6% and a high current efficiency of 22.9 cd/A were obtained from the PVK:FIrpic PHOLED due to efficient exciton blocking and electron injection.