Universal Display Corporation
Organic electroluminescent materials and devices

Abstract:

A compound having a first ligand L.sub.A having the Formula: ##STR00001## Formula I is disclosed, wherein rings A is a 5- or 6-membered carbocyclic or heterocyclic ring; wherein R.sup.A and R.sup.B each independently represent mono to the possible maximum number of substitution, or no substitution; wherein Z.sup.1 is carbon or nitrogen; wherein each R.sup.A and R.sup.B is independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; wherein any two substituents are optionally joined or fused into a ring; wherein X.sup.1 to X.sup.4 each independently represent a carbon or nitrogen; wherein at least one of X.sup.1 to X.sup.4 is nitrogen; wherein the ligand L.sub.A is coordinated to a metal M; wherein the metal M can be coordinated to other ligands; and wherein the ligand L.sub.A is optionally linked with other ligands to comprise a tridentate, tetradentate, pentadentate or hexadentate ligand.