Highly efficient polymer light-emitting diodes using color-tunable carbazole-based iridium complexes

Two novel carbazole-based iridium(III) complexes with green and red emission have been prepared by the ligation of iridium with carbon at the 3- and 2-position of carbazole unit, respectively. Highly efficient polymer light-emitting devices by using the two complexes as dopant emitters, both non-conjugated polymer (PVK) and conjugated polymer, polyhedral oligomeric silsesquioxane-terminated poly(9,9-dioctylfluorene) [PFO(poss)], as the host materials, have been achieved. The maximal external quantum efficiency, luminance efficiency and brightness for red PLED are 5.95% ph/el, 5.56 cd/A and 6402 cd/m2, respectively, and those for green PLED are 8.51% ph/el, 18.77 cd/A and 11845 cd/m2, respectively.