Efficient Low-Driving-Voltage Blue Phosphorescent Homojunction Organic Light-Emitting Devices

摘要

A blue phosphorescent p-i-n homojunction organic light-emitting device with a low driving voltage was demonstrated using 4,6-bis[3-(carbazol-9-yl)phenyl] pyrimidine (46DCzPPm) as the bipolar host material and iridium(lll) bis[4,6-(difluorophenyl)pyridinato-N,C~2'] picolinate as the blue triplet emitter. The device incorporated an n-doping electron-transport layer consisting of Cs_2CO_3-doped 46DCzPPm and a p-doping hole-transport layer consisting of MoO_3-doped 46DCzPPm. A maximum external quantum efficiency of 10.2% and a power efficiency of 27.8 lm W~(-1) were obtained. At 100cdnm~(-2), the efficiencies were 9.1% and 21.5Im W~(-1), and even at 1000cd m~(-2), the efficiencies remained at 7.0% and 12.8lm W~(-1), respectively, with an extremely low driving voltage of 3.9 V.