| 초록 |
A new series of homoleptic cyclometalated iridium(III) complexes based on the phenylpyridine (ppy) ligand containing bulky substituents synthesized and characterized. Comparison of the results with those of the reference Ir(ppy)3 reveal that the emission color and photophysical properties of the other Ir complexes are influenced by the electron-donating groups attached to the ppy ligand. Systematic red-shifts are observed by increasing the electron-donating ability. The emission spectrum of Ir(Me-ppy)3, having small electron-donating group, is red-shifted; but, the emission quantum yield is low and the nonradiative decay constant is large. Otherwise, although bulky phenyl derivative-adducts also exhibit red-shifted emission, but their kinetic and photophysical behaviors are more optimal than those of Ir(Me-ppy)3, whose behavior does not follow the energy gap law. This deviation may be attributed to the rigid environment associated with the steric hindrance of a bulky substituent. |
