Universal Display Corporation
ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES

Abstract:

A compound having an ancillary ligand L.sup.1 having the formula: ##STR00001## Formula I is disclosed. The ligand L.sup.1 is coordinated to a metal M having an atomic number greater than 40, and two adjacent substituents are optionally joined to form into a ring. Such compound is suitable for use as emitters in organic light emitting devices.