Synthesis and electrophosphorescent performances of alkyl-substituted bicycloiridium complexes in polymer light-emitting diodes

摘要

In this paper, two complexes (mppy)_2Ir(tmd) and (bppy)_2Ir(tmd) were synthesized and doped into PVK. We find that the alkyl substitution of bicycloiridium complexes on acetylacetonate ligand has a great effect on optimizing the PLED performances. The best device performance is observed for the (bppy)_2Ir(tmd)-doped PVK-PBD (40 wt percent) device with the concentration of 1 wt percent. A maximal external quantum efficiency of QE_(ext) = 14.2 percent ph/el and the luminous efficiency of LE = 33 cd/A with a luminance of 2099mA/cm~2 were achieved at a current density of 6.4mA/cm~2.