Organic electroluminescent materials and devices

A first organic light emitting device comprising:

• an anode;
• a cathode;
• and
• an organic layer, disposed between the anode and the cathode, comprising a compound comprising a carbene ligand LA of Formula I:
• Formula I;
• wherein ring A is a 5-membered or 6-membered carbocyclic or heterocyclic ring;
• wherein Z is nitrogen or carbon;
• wherein R7 represents from mono-substitution to the possible maximum number of substitution, or no substitution;
• wherein R3, R4, and R7 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 adjacent substituents of R1, R2, R3, R4, R5, R6, and R7 are optionally joined or fused into a ring, and cannot be joined or fused into a double bond;
• wherein the ligand LA is coordinated to a metal M through the carbene carbon and Z;
• wherein the ligand LA is optionally linked with other ligands to comprise a tridentate, tetradentate, pentadentate or hexadentate ligand,
• wherein R1, R2, R5, and R6 are selected from the group consisting of alkyl, cycloalkyl, partially or fully fluorinated variants thereof, partially or fully deuterated variants thereof, and combinations thereof, and
• wherein R5 and R6 are joined into a ring.

A formulation comprising a compound comprising a carbene ligand LA of Formula I:

• Formula I;
• wherein ring A is a 5-membered or 6-membered carbocyclic or heterocyclic ring;
• wherein Z is nitrogen or carbon;
• wherein R7 represents from mono-substitution to the possible maximum number of substitution, or no substitution;
• wherein R3, R4, and R7 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 adjacent substituents of R1, R2, R3, R4, R5, R6, and R7 are optionally joined or fused into a ring, and cannot be joined or fused into a double bond;
• wherein the ligand LA is coordinated to a metal M through the carbene carbon and Z;
• wherein the ligand LA is optionally linked with other ligands to comprise a tridentate, tetradentate, pentadentate or hexadentate ligand,
• wherein R1, R2, R5, and R6 are selected from the group consisting of alkyl, cycloalkyl, partially or fully fluorinated variants thereof, partially or fully deuterated variants thereof, and combinations thereof, and
• wherein R5 and R6 are joined into a ring.