Smart Design on the Cyclometalated Ligands of Iridium(III) Complexes for Facile Tuning of Phosphorescence Color Spanning from Deep-Blue to Near-Infrared

It has long been a challenge to achieve iridium(III) complexes with emission colors covering the whole visible and near-infrared wavelengths, by using similar cyclometalating ligands. Herein, a series of iridium(III) complexes that accomplish broadly tunable phosphorescence from 420 to 729 nm through the use of trifluoromethyl substituents and other conjugated units such as [1,2,5] thiadiazolo[3,4-c] pyridine in the cyclometalating ligands are reported. The peak external quantum efficiencies of 7.1%, 20.0%, 14.0%, 4.0%, and 16.0% are achieved for deep-blue, green, red, near-infrared, and white phosphorescent organic light-emitting diodes, respectively, by using these iridium(III) complexes.