Highly Efficient Phosphorescent Furo[3,2-c]pyridine Based Iridium Complexes with Tunable Emission Colors over the Whole Visible Range.

Abstract

A series of highly efficient phosphorescent Ir complexes with tunable emission colors over the whole visible range have been designed and synthesized based on furo[3,2-c]pyridine ligand. By mainly varying the molecular structures of the C-chelated blocks, the emission maxima of these complexes can be obviously tailored from 477 to 641 nm while keeping the considerable photoluminescence quantum yields (PLQYs) (0.55-0.78 at wavelength of 475-560 nm and 0.10-0.34 at wavelength of 590-640 nm). Correspondingly, the phosphorescent organic light-emitting diodes (OLEDs) achieve high-performance greenish-blue, green, greenish-yellow, orange, red, and deep-red electrophosphorescence, revealing state-of-art external quantum efficiences (EQEs) of 20.0% (46.6 cd/A), 31.8% (89.0 cd/A), 19.9% (71.9 cd/A), 16.6% (38.9 cd/A), 12.0% (16.7 cd/A), and 8.5% (7.3 cd/A) as well as Commision Internationale de L'Eclairage (CIE) coordinates of (0.25, 0.48), (0.30, 0.58), (0.43, 0.54), (0.62, 0.37), (0.66, 0.32), and (0.70, 0.29), respectively. The results clearly demonstrate the great potential of furo[3,2-c]pyridine based phosphors used for full-color OLED displays.