초록 |
Highly efficient orange phosphorescent iridium(III) complexes, (DMBT)2Ir(acac) and (TBT)2Ir(acac) based on 2-(3,4-dimethylphenyl)benzo[d]thiazole (DMBT) or 2-(4-(trimethylsilyl)phenyl)benzo[d]thiazole (TBT) as a cyclometalated main ligands and acetylacetone (acac) as an ancillary ligand were synthesized for solution-processed organic light-emitting diodes (OLEDs). The photophysical, electrochemical, and electroluminescent (EL) properties of Iridium(III) complexes were investigated. Among the iridium(III) complexes, orange OLEDs using the (TBT)2Ir(acac) exhibited significantly more improved luminance and external quantum efficiency with markedly prevented concentration self-quenching at high doping concentration by introduction of bulky trimethylsilyl groups. The device with 7 wt% doping concentration of (TBT)2Ir(acac) exhibited maximum luminance of 6,837 cd/m2, maximum luminous efficiency of 25.26 cd/A,and external quantum efficiency of 9.94 %, respectively. |