Universal Display Corporation
ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES

Abstract:

A novel compound is disclosed which includes a ligand L.sub.A of Formula I, Formula II, Formula III, or Formula IV: ##STR00001## wherein: ring B is independently a 5-membered or 6-membered carbocyclic or heterocyclic ring; X.sup.1 to X.sup.4 are each independently selected from the group consisting of C, N, and CR; at least one pair of adjacent X.sup.1 to X.sup.4 are each C and fused to a structure of Formula V ##STR00002## where indicated by ""; X.sup.5 to X.sup.12 are each independently C or N; the maximum number of N within a ring is two; Z and Y are each independently selected from the group consisting of O, S, Se, NR', CR'R'', SiR'R'', and GeR'R''; R.sup.B and R.sup.C each independently represents zero, mono, or up to a maximum allowed substitutions to its associated ring; each of R.sup.B, R.sup.C, R, R', and R'' is independently hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, boryl, and combinations thereof; and two substituents can be joined or fused to form a ring; the ligand L.sub.A is complexed to a metal M through the two indicated dash lines of each Formula; and the ligand L.sub.A can be joined with other ligands to form a tridentate, tetradentate, pentadentate, or hexadentate ligand.