Abstract
The present invention provides a phosphorescent tris-chelated transition metal complex having one carbon-nitrogen (C^N) or nitrogen-nitrogen (N^N) chromophoric ligand forming a coordination sphere thereof with a transition metal, and two identical carbon-phosphorus (C^P) chelates being incorporated into the coordination sphere, wherein the metal is iridium, platinum, osmium or ruthenium, and the chromophoric ligands possess a relatively lower energy gap in comparison with that of the non-chromophoric chelate, the latter afforded an effective barrier for inhibiting the ligand-to-ligand charge transfer process, so that bright phosphorescence can be observed. The architecture and energy gap of the present molecular designs are suitable for generation of high efficiency blue, green and even red emissions.