Blue Phosphorescent Bipyridine-Based Iridium(III) Complex for Vacuum-Deposited Organic Light-Emitting Diodes.

We have synthesized and characterized a blue phosphorescent iridium(III) complex (dfpypy)2Ir(tftamp), which contains 2',6'-difluoro-2,3'-bipyridine (dfpypy) as the main ligand and 4-methyl-2-(3'-trifluoromethyl-1'H-1',2',4'-triazol-5'-yl)pyridine (tftamp) as the ancillary ligand. The photophysical, electrochemical, and electroluminescent (EL) properties of (dfpypy)2Ir(tftamp) were investigated. Vacuum-deposited blue and white organic light-emitting diodes (OLEDs) were fabricated using (dfpypy)2Ir(tftamp) in 1,3-bis(carbazol-9-yl)benzene (mCP) as the emitting layer. The EL spectrum of (dfpypy)2Ir(tftamp) exhibited emission maximum at 472 nm with a full-width at half-maximum (FWHM) of 81 nm and Commission Internationale de L'Eclairage (CIE) coordinates of (0.17, 0.27) at 100 cd · m-2. In addition, white-light-emitting devices were fabricated, which exhibited CIE coordinates of (0.42, 0.40) and a correlated color temperature (CCT) of 3,237 K at 1000 cd · m-2, close to the standard warm-white light CIE coordinates of (0.44, 0.40) and CCT of 3,000 K.