Homoleptic Cyclometalated Dibenzothiophene-NHC-Iridium(III) Complexes for Efficient Blue Phosphorescent Organic Light-Emitting Diodes
발표자
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초록
내용
The NHC-Ir complexes f-IrSiPr, m-IrSiPr, and m-IrSMe, in which a dibenzothiophene (DBT) moiety is used to increase the emission efficiency for deep blue phosphorescence, were synthesized and compared with the dibenzofuran (DBF)-based Ir complexes f-IrOMe and m-IrOMe. The differences in the ligand structure (DBF/DBT) or configuration (fac/mer) of these complexes led to different electrochemical and photophysical properties. Even with the differences in the origin of phosphorescence, replacement of the oxygen atom in the DBF unit with sulfur does not greatly alter the emission efficiency in either solution or film, while achieving the same high-end deep-blue phosphorescence with unprecedented CIE coordinates of [0.14,0.19] for m-IrSMe (EQEmax; 17.1%) and [0.14,0.14] for m-IrOMe (EQEmax; 18.2%).