Novel yellow phosphorescent iridium complexes with cycolmetalated (pyridin-2-yl)dibenzothiophene-S,S-dioxide ligands for singly doped emissive layer hybrid white organic light-emitting diodes

Two novel dibenzothiophene-S,S-dioxide-based iridium complexes with yellow emission were fully synthesized and characterized. The photophysical, electrochemical and thermal properties, as well as electroluminescent properties of the resulting iridium complexes were discussed. Both the iridium complexes possess good thermal stability and high photoluminescence quantum yields. Also, we have successfully fabricated singly doped emissive layer (SDEL) hybrid white organic light-emitting devices (WOLEDs) using (3-PyFSO)(2)IrPic or (2-PyFSO)(2)IrPic as yellow-emitting phosphors and 4,4',4 ''-tris(N-carbazolyl)triphenylamine (TCTA) as host and blue-emitting fluorophor. The WOLEDs with (3-PyFSO)(2)IrPic show a maximal power efficiency (PE) of 4.28 lm/W at a brightness of 3.7 cd/m(2) and a Commission Internationale de L'Eclairage (CIE) coordinates of (0.227, 0.260). Compared to (3-PyFSO)(2)IrPic, the WOLEDs based on (2-PyFSO)(2)IrPic exhibit a little better device's performances with a maximum PE of 4.70 lm/W at a brightness of 2.6 cd/m(2) and a CIE coordinates of (0.244, 0.243).