| 초록 |
Four new heteroleptic Ir(III) complexes Ir1, Ir2, Ir3, and Ir4 consisting of 2′,4″-difluorophenylpyridine (dfppy) with cyano (CN) group at 5′-position of the phenyl and tert-butyl (tBu) group at 4-position of the pyridine as main ligand and new β–diketonate derivatives as ancillary ligands were synthesized and characterized for phosphorescent organic light-emitting diodes (PhOLEDs). Upon UV-irradiation, Ir4 has emitted intense blue light with well resolved vibronic peak at wavelength (λmax) 460, 489 nm, indicating the 3π-π* character of the lowest emitting excited state; while Ir3 and Ir1 have emitted blue light at 462 nm and 466 nm, respectively, with a small or unresolved vibronic peak at 489 nm due to the admixture of 3MLCT and 3π-π* characters in the lowest emitting excited state. Ironically, Ir2 has a broad structureless emission in green region with λmax at 545 nm as an obvious representation of 3MLCT dominance in lowest excited state. |
