Organic electroluminescent materials and devices

A compound of formula Ir(LA)x(LB)y comprising a structure of Formula I:

• wherein:
• each of x and y is independently 1 or 2, and x+y=3;
• each of X1 to X17 is independently C or N;
• each of RA, RB, RC, RD, and RE independently represents mono to the maximum allowable substitutions, or no substitutions;
• each R1, R2, R3, R4, RA, RB, RC, RD, and RE is independently hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, germyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, selenyl, and combinations thereof;
• any two substituents may be joined or fused to form a ring;
• at least one of R1, R2, R3, or R4 is not hydrogen, deuterium, or halogen;
• each of R1, R2, R3, and R4 have a corresponding cone angle R1(CA), R2(CA), R3(CA), and R4(CA);
• each of R1, R2, R3, and R4 have a corresponding Van der Waals surface area R1(VdW), R2(VdW), R3(VdW), and R4(VdW);
• and
• at least one of the following is true:
• (i) R1(VdW)+R3(VdW)≥210.6 Å2, and at least one of R1(CA) or R3(CA) is ≥ a target cone angle,
• (ii) R1(VdW)+R4(VdW)≥210.6 Å2, and at least one of R1(CA) or R4(CA) is ≥ the target cone angle,
• (iii) R2(VdW)+R3(VdW)≥210.6 Å2, and at least one of R2(CA) or R3(CA) is ≥ the target cone angle, or
• (iv) R2(VdW)+R4(VdW)≥210.6 Å2, and at least one of R2(CA) or R4(CA) is ≥ the target cone angle;
• wherein the target cone angle is 35 degrees.