Organic electroluminescent materials and devices

A compound having the formula [LA]3-nIr[LB]n, having the structure:

• wherein R1, R2, R3, R4, and R5 each independently represents mono, to a maximum possible number of substitutions, or no substitution;
• wherein X is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═O, S═O, SO2, CR′R″, SiR′R″, and GeR′R″;
• wherein R′, R″, R1, R2, R3, R4, and R5 are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;
• wherein any substitutions are optionally joined or fused into a ring;
• wherein n is 1 or 2;
• wherein R is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, partially or fully fluorinated variants thereof, partially or fully deuterated variants thereof, and combination thereof;
• wherein R has at least five carbon atoms;
• wherein at least one of R2 is nitrile;
• and
• wherein the compound comprises at least one tert-butyl group.

An organic light emitting device (OLED) comprising:

• an anode;
• a cathode;
• and
• an organic layer, disposed between the anode and the cathode, comprising a compound having the formula:
• wherein R1, R2, R3, R4, and R5 each independently represents mono, to a maximum possible number of substitutions, or no substitution;
• wherein X is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C—O, S═O, SO2, CR′R″, SiR′R″, and GeR′R″;
• wherein R′, R″, R1, R2, R3, R4, and R5 are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;
• wherein any substitutions are optionally joined or fused into a ring;
• wherein n is 1 or 2;
• wherein R is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, partially or fully fluorinated variants thereof, partially or fully deuterated variants thereof, and combination thereof;
• wherein R has at least five carbon atoms;
• and
• wherein at least one of the following conditions is true:
• (1) at least one of R2 is nitrile;
• or
• (2) the compound comprises at least one tert-butyl group.