Patent ID: 7332232

Claim:
An organic light emitting device comprising an anode, a cathode, and an organic layer disposed between the anode and the cathode, wherein the organic layer comprises a phosphorescent organometallic emissive material comprising a transition metal, Tl, Pb, Bi, In, Sn, Sb or Te, and two or three bidentate ligands, wherein two or more of the bidentate ligands are covalently linked by a linking group, wherein, the bidentate ligands are selected from bidentate photoactive ligands, wherein each bidentate photoactive ligand is bound to the transition metal, Tl, Pb, Bi, In, Sn, Sb or Te through a carbon-metal bond and a nitrogen-metal bond to form a cyclometallated ring, and bidentate ancillary ligands, wherein at least one of the bidentate ligands is a bidentate photoactive ligand.