Universal Display Corporation
Organic electroluminescent materials and devices

Abstract:

A compound comprising a first ligand L.sub.A of Formula I, ##STR00001## is disclosed. In the structure of Formula I, ring A is a 5-membered or 6-membered carbocyclic or heterocyclic ring; Z.sup.1-Z.sup.4 are each independently C or N; at least two consecutive Z.sup.1-Z.sup.4 are C, and are fused to a structure of ##STR00002## or ##STR00003## Y.sup.1 and Y.sup.2 are each independently O, S, Se, CRR', SiRR', or GeRR'; each R.sup.A, R.sup.B, R.sup.C, R, and R' is a hydrogen or a substituent; and any two substituents may be joined or fused together to form a ring. In the compound, L.sub.A is complexed to a metal M by the dashed lines in Formula I to form a five-membered chelate ring, and M has an atomic weight greater than 40. Organic light emitting devices and consumer products containing the compounds are also disclosed.