Universal Display Corporation
ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES

Abstract:

A compound having a formula M(L.sub.A).sub.x(L.sub.B).sub.y(L.sub.C).sub.z, where ligand L.sub.A is ##STR00001## ligand L.sub.B is ##STR00002## and ligand L.sub.C is ##STR00003## is disclosed. In formula M(L.sub.A).sub.x(L.sub.B).sub.y(L.sub.C).sub.z, M is a metal having an atomic number greater than 40; x is 1 or 2; y and z are independently 0, 1, or 2; x+y+z is the oxidation state of the metal M; A.sup.1-A.sup.8 are carbon or nitrogen; ring B is bonded to ring A through a C--C bond; M is bonded to ring A through a M-C bond; X is O, S, Se, CRR', or NR.sup.1; rings C and D are each independently a 5 or 6-membered carbocyclic or heterocyclic ring; at least one R.sup.4 is a five-membered or six-membered heterocyclic ring which can be further substituted by R.sup.E; each R substituent is independently selected from the general substituents; and any adjacent R substitutents are optionally joined to form a ring.