Universal Display Corporation
ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES

Abstract:

A compound comprising a ligand L.sub.A of Formula I, ##STR00001## is disclosed. In Formula I, ring A is a 5- or 6-membered ring; R is formula II, ##STR00002## and is fused to ring B to form ring C; each of X.sup.1, X.sup.2, X.sup.3, and X.sup.4 is carbon or nitrogen; X is selected from a variety of bivalent moieties; each R.sup.1 to R.sup.4, R', and R'' is hydrogen or a substituent; at least one 6-membered ring carbon that is part of Ring A, Ring B, or a fused ring system comprising Ring A or Ring B is substituted with deuterium; and K.sup.1 is selected from a direct bond, O, and S. Formulations, OLEDs, and consumer products including the compound are also disclosed.