Efficient and low-voltage phosphorescent organic light-emitting devices based on blue iridium complex host

By adopting a phosphorescent host/guest system consisting of blue iridium complex as host and a series of phosphorescent dyes as guest, efficient and low-voltage monochromic organic light-emitting devices(OLEDs) were fabricated. The devices with blue iridium host have higher power efficiency than the device with the conventional host 4,4′-N,N′-dicarbazole-biphenyl. The enhancement of the maximum power efficiency in green phosphorescent device can reach 37.2%. Dichromatic white OLED could be achieved by simply adjusting the concentration of the orange dyes. At a brightness of 1000 cd/m2, the power efficiency of the white device is 8.4 lm/W with a color rendering index of 76.