| 초록 |
The Ir(C^N)3 complexes involve attaching a methyl, phenyl, terphenyl, and isopropyl-terphenyl group to the parent phenylimidazole ligand, abbreviated as MI, PI, TPI, and ITPI, respectively. Additional iridium complexes, TPIF and ITPIF, are also prepared in which the phenyl moiety of phenylimidazole was modified with electron-withdrawing substituents (e.g., -F). It is turned out that a terphenyl molecular fragment not only elevated LUMO but also increased emission quantum yield significantly. With terphenyl modification and further color tuning by adding fluorine and isopropyl groups, ITPIF showed blue phosphorescence at 456 nm as well as high quantum yields (40% in solution and 76% in PMMA film). This ITPIF complex is selected as a dopant material in the structure of blue phosphorescent organic light-emitting diodes. The highly efficient blue OLED can be realized with a maximum EQE of over 16.4% with CIE value of (0.18, 0.27). |
