| 초록 |
We have synthesized four cyclometalated heteroleptic Ir(III) complexes using benzothiazole linked ethylcarbazole (Et-Cz-BTz) as a main ligand and picolinic acid [(Et-Cz-BTz)2Ir(pic)], picolinic acid N-oxide [(Et-Cz-BTz)2Ir(pic-N-O)], 4-(2-ethoxyethoxy)picolinic acid [(Et-Cz-BTz)2Ir(EO2-pic)], 4-(2-ethoxyethoxy)picolinic acid N-oxide [(Et-Cz-BTz)2Ir(EO2-pic-N-O)] as ancillary ligands, for solution processed phosphorescent organic light-emitting diodes (PhOLEDs). The ethoxyethanol was introduced as a solubilizing group into the ancillary ligand by tandem reaction. All the Ir(III) complexes emit bright yellow (541 nm–582 nm) phosphorescence at room temperature. The yellow PhOLEDs were fabricated with the configuration of ITO/GraHIL11 (40 nm)/TCTA:TPBI (40 nm)/Ir(III) complexes (15 wt%)/TPBI (50 nm)/LiF (1 nm)/Al (90 nm). Among the four Ir(III) complexes, the [(Et-Cz-BTz)2Ir(EO2-pic)] showed the best luminous efficiency of 60 cd/A and external quantum efficiency of 19% with CIE coordinates (0.467, 0.524). |
