Patent ID: RE42561

Claim:
An organic light emitting device comprising an anode, a cathode and an emissive layer, wherein the emissive layer is located between the anode and the cathode and the emissive layer comprises an electron transporting host material doped with a phosphorescent dopant material, wherein the phosphorescent dopant material is an organometallic complex having the formula selected from L 3 M and L 2 MX, wherein M is a third row transition metal; L is a monoanionic bidentate ligand that is coordinated to M with an sp 2 hybridized carbon and a heteroatom of the ligand L; and X is a monoanionic bidentate ligand; and wherein the phosphorescent dopant material has a HOMO energy less than the ionization potential of the electron transporting host material and a LUMO energy level lower than a LUMO energy level of the electron transporting host material.