초록 |
We synthesized and characterized the new orange-emitting iridium(III) complexes, (DMBT)2Ir(acac) and (TBT)2Ir(acac), based on either 2-(3,4-dimethylphenyl)benzo[d]thiazole (DMBT) or 2-(4-(trimethylsilyl)phenyl)benzo[d]thiazole (TBT) as the cyclometalated main ligands and acetylacetone (acac) as an ancillary for solution-processed OLEDs. The iridium(III) complex, (BT)2Ir(acac) was also synthesized for reference. The photophysical, electrochemical, and electroluminescent (EL) properties of these iridium(III) complexes were investigated. The OLED fabricated using (TBT)2Ir(acac) exhibited a dramatically improved luminance and external quantum efficiency (EQE) with prevented concentration self-quenching at high doping concentrations by introducing bulky trimethylsilyl groups. The device with 7 wt% (TBT)2Ir(acac) doping concentration exhibited a highest luminance of 6,837 cd/m2, maximum luminous efficiency of 25.26 cd/A, power efficiency of 12.37 lm/W, and EQE of 9.94%. |