Universal Display Corporation
ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES

Abstract:

Compounds comprising a first ligand L.sub.A of ##STR00001## are disclosed. In L.sub.A, ring B is a 5- or 6-membered ring; Y is O, S, NR.sup.Y, or CR.sup.YR.sup.Y'; Z.sup.1 is O, S, NR, or CRR'; X.sup.1 is C or N; each R, R', R.sup.Y, R.sup.Y', R.sup.A, and R.sup.B is hydrogen or a substituent; L.sub.A is coordinated to a metal M b.sub.y the dashed lines; any two of R, R', R.sup.Y, R.sup.Y', R.sup.A, and R.sup.B can be joined to form a ring; and with the proviso that the compound does not comprise Formula II, ##STR00002## wherein each of Z' and Z'' is C or N. Formulations, OLEDs, and consumer products containing the compound are also disclosed.