Universal Display Corporation
ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES

Abstract:

A compound including a first ligand L.sub.A of Formula I, ##STR00001## is disclosed. In Formula I, ring B is a 5- or 6-membered ring; X.sup.1, X.sup.2, and X.sup.3 are each CR.sub.A or N; R is a 5- or 6-membered carbocyclic or heterocyclic ring, which can be further fused or substituted; and (1) when ring B is an unfused 6-membered ring, X.sup.1 and X.sup.2 are N, and X.sup.3 is C; and (2) when ring B is a fused 6-membered ring, ring B has the structure of Formula II, ##STR00002## In this structure, the wavy line indicates the point of connection to ring A; Q.sup.1 to Q.sup.6 are each C or N; and, when proviso (2) applies, (I) at least one of X.sup.1, X.sup.2, and X.sup.3 is N; or (II) R is two or more fused or unfused 5- or 6-membered carbocyclic or heterocyclic rings, or (III) at least ring A or R is substituted with a partially or fully deuterated alkyl or partially or fully deuterated cycloalkyl group.