Highly efficient saturated red electrophosphorescence from isoquinoline-based iridium complex containing triphenylamino units in polymer light-emitting devices

To obtain highly efficient saturated red-emitting polymer light-emitting devices, the opto-physical and electrophosphorescent properties of a novel isoquinoline-based iridium complex containing triphenylamino units were investigated. The devices using this iridium complex as a dopant and a blend of poly(9,9-dioctylfluorene) and 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole as a host matrix displayed bright saturated red emission at 637 nm with Commission Internationale de I’Eclairage coordinate of (0.64, 0.31). The maximum external quantum efficiency of 10.8% photos/electron and current efficiency of 4.6 cd/A at 1.7 mA/cm2, and the peak brightness of 5453 cd/m2 at 228 mA/cm2 were obtained in the device at 2% dopant concentration.