A novel cyclometalated Iridium(III) complex containing dibenzo-24-crown-8: synthesis, luminescence and application in highly efficient green phosphorescent OLEDs

Several new iridium complexes with the dibenzo-24-crown-8 substituted 2-penylpyridine (ppy) ligand have been synthesized and characterized. These iridium complexes emit green light with a high photoluminescence quantum yield ranging from 0.56 to 0.63 and exhibit good thermal properties. The complexes were incorporated into phosphorescent polymer light-emitting devices (PLEDs) using soluble poly(N-vinylcarbazole) (PVK) as the host and the resultant iridium complexes as dopants. High-efficiency green electrophosphorescence was observed, with peak emission at about 520 nm. Among these devices, the PLEDs with G3 as the dopant displayed the best EL performances. An external quantum efficiency of 10.92% and a luminous efficiency of 29.6 cd A(-1) were obtained at 537 cd m(-2).