Organic electroluminescent materials and devices

A compound of Formula Ir(LA)m(LB)n, wherein:

• m and n are each independently 1 or 2;
• m+n=3;
• LA has a structure of Formula I,
• LB has a structure of Formula II,
• moiety D is a monocyclic ring or a polycyclic fused-ring system, wherein the monocyclic ring and each ring of the polycyclic fused-ring system is independently a 5-membered or 6-membered carbocyclic or heterocyclic ring;
• moiety D comprises of a maximum of three fused rings;
• R is selected from the group consisting of H, D, methyl, and partially or fully deuterated methyl;
• RA, RB, RC, RD, and RE each independently represent mono to the maximum allowable substitution, or no substitution;
• each R1, R2, R3, R4, R5, R6, RA, RB, RC, RD, and RE is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, boryl, arylalkyl, alkoxy, aryloxy, amino, silyl, germyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, selenyl, and combinations thereof;
• at least one of the following two statements is true:
• (1) R4 and R5 collectively comprise three or more carbon atoms, or
• (2) R6 comprises three or more carbon atoms;
• and
• any two substituents may be joined or fused to form a ring.