Universal Display Corporation
ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES

Abstract:

A compound including a first ligand L.sub.X of Formula II ##STR00001## is disclosed, where F is a 5-membered or 6-membered carbocyclic or heterocyclic ring; each R.sup.F and R.sup.G independently represents mono to the maximum possible number of substitutions, or no substitution; Z.sup.3 and Z.sup.4 are each independently C or N and coordinated to a metal M to form a 5-membered chelate ring; G is a fused ring structure comprising five or more fused heterocyclic or carbocyclic rings, of which one or two rings are of Formula III ##STR00002## the fused heterocyclic or carbocyclic rings in the fused ring structure G are 5-membered or 6-membered; of which if two or more 5-membered rings are present, at least two of the 5-membered rings are fused to one another; Y can be one of BR', NR', PR', O, S, Se, C.dbd.O, S.dbd.O, SO.sub.2, CR'R'', SiR'R'', and GeR'R''; the metal M can be coordinated to other ligands; and the ligand L.sub.X can be linked with other ligands to comprise a tridentate, tetradentate, pentadentate, or hexadentate ligand.