Yellow organic light-emitting diodes based on phosphorescent iridium(III) pyrazine complexes: Fine tuning of emission color

The synthesis and luminescence of a series of new iridium pyrazine complexes were investigated. The phosphorescent peak wavelength can be fine-tuned in yellow color range of 553–588 nm. Complexes 4 and 6 were used as representative examples for fabrication of multilayered OLEDs. The two OLEDs all exhibited high efficiency. The devices based on complex 4 exhibited an external quantum efficiency of 4.6% (power efficiency 9.7l m/W) and a maximum brightness of 32 700 cd/m2. The device also showed high color purity with an emission maximum at 561 nm and Commission Internationale de l’Eclairage (CIE) coordinates of (x = 0.45, y = 0.54).