Ruijuan Yao, Di Liu, F. Wang
Jan 1, 2019
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0
Influential Citations
5
Citations
Journal
Dyes and Pigments
Abstract
Abstract Two tris-cyclometalated heteroleptic iridium complexes incorporating 2-(2,4-difluorophenyl)pyridine (dfppy) as the main cyclometalating ligand, 2′,6′-Difluoro-2,3′-bipyridine (dfbpy) or 3-(1-benzyl-1H-1,2,3-triazol-4-yl)pyridine (pt) as the second cyclometalating ligand, namely Ir(dfppy)2(pt) (M1) and Ir(dfppy)2(dfbpy) (M2), were developed for application as blue phosphors in organic light-emitting diodes (OLEDs). The spectroscopic behavior of the complex phosphors was correlated with the ligand properties. With incorporation of the high-triplet-energy pt as the second cyclometalating ligand in Ir(dfppy)2(pt), the phosphorescence spectrum was slightly hypsochromatically shifted and narrowed with reduced intensity in long-wavelength vibration band, resulting in improved blue color purity in comparison with the traditional sky-blue iridium complex FIrpic. In simple-structure phosphorescence OLEDs, Ir(dfppy)2(pt) exhibited a current efficiency of 19.1 cd A−1 (EQE of 10.7%), while Ir(dfppy)2(dfbpy) exhibited an efficiency of 24.2 cd A−1 (EQE of 11.2%).