Recent Progress in Phenoxazine-Based Thermally Activated Delayed Fluorescent Compounds and Their Full-Color Organic Light-Emitting Diodes

Highly Efficient Red-Emitting OLEDs Prepared from Nona-Coordinated Europium(III) Complexes

“…The establishment of the photoluminescence (PL) properties of organo–lanthanide complexes has strengthened their position among the many available functional materials and makes them suitable for potential technological applications, particularly organoeuropium complexes (OEuCs) in OLEDs, − as sensors, as sensitizers to improve the OLED performance of the state-of-the-art red-emitting iridium­(III) complexes, and as luminescent thermometers. , Among the large number of monochromatic red-emitting OEuCs, easily obtainable tris­(β-diketonato)­Eu­(III) complexes incorporating polydentate ancillary ligand(s) [N̂N/ÔO/N̂N̂N/ÔÔO] , could provide a cheap and environmental-friendly alternative to the sought-after red-emitting phosphorescent complexes − and thermally activated delayed fluorescence (TADF) , materials that dominate the OLED field. This is due to their innate photophysical properties, specifically their highly monochromatic red emission with a full width at half maxima (fwhm) < 15 nm, resulting in excellent color purity and high photoluminescence quantum yields (PLQYs). , Another important prerequisite for developing efficient OLEDs is the good electron-transport properties of the compounds/complexes in question .…”