ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES

1 . A compound having the formula Ir(L A ) n (L B ) 3-n , wherein L A is an aza-dibenzofuran ligand and L is an alkyl-substituted phenylpyridine ligand;

wherein the compound has a structure according to Formula I:

wherein A 1 , A 2 , A 3 , A 4 , A 5 , A 6 , A 7 , and A 8 comprise carbon or nitrogen;

wherein at least one of A 1 , A 2 , A 3 , A 4 , A 5 , A 6 , A 7 , and A 8 is nitrogen;

wherein ring B is bonded to ring A through a C—C bond;

wherein the iridium is bonded to ring A through a Ir—C bond;

wherein X is O, S, or Se;

wherein R 1 and R 2 each independently represent mono-, di-, tri-, tetra-substitution, or no substitution;

wherein R′ and R″ each independently represent mono-, di-substitution, or no substitution;

wherein any adjacent substitutions in R′, R″, R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are optionally linked together to form a ring;

wherein R 1 , R 2 , R′, and R″ are each 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, nitrite, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof,

wherein R 3 , R 4 , R 5 , and R 6 are each independently selected from the group consisting of hydrogen, deuterium, alkyl, cycloalkyl, and combinations thereof;

wherein n is an integer from 1 to 3; and

wherein total number of carbons in at least one of the pairs R 3 and R 4 , and R 5 and R 6 is at least four.

2 . The compound of claim 1 , wherein n is 1.

3 . The compound of claim 1 , wherein the compound has a structure according to Formula II:

4 . The compound of claim 1 , wherein the compound has a structure according to Formula III:

5 . The compound of claim 1 , wherein the compound has a structure according to Formula IV:

6 . The compound of claim 1 , wherein only one of A 1 to A 8 is nitrogen.

7 . The compound of claim 6 , wherein one of A 5 to A 8 is nitrogen.

8 . The compound of claim 1 , wherein X is O.

9 . The compound of claim 1 , wherein R 1 and R 2 are each independently selected from the group consisting of hydrogen, deuterium, alkyl, cycloalkyl, and combinations thereof.

10 . The compound of claim 1 , wherein at least one of the following conditions (1) and (2) is true:

(1) R 3 and R 4 are each independently selected from the group consisting of alkyl, cycloalkyl, partially or fully deuterated variants thereof, and combinations thereof; and total number carbons in R 3 and R 4 combined is at least four; and

(2) R 5 and R 6 are each independently selected from the group consisting of alkyl, cycloalkyl, partially or fully deuterated variants thereof, and combinations thereof; and total number of carbons in R 5 and R 6 combined is at least four.

11 . The compound of claim 1 , wherein at least one of the following conditions (1) and (2) is true:

(1) R 3 and R 4 are each independently selected from the group consisting of alkyl, cycloalkyl, partially or fully deuterated variants thereof, and combinations thereof; at least one of R 3 and R 4 contain at least one deuterium; and total number of carbons in R 3 and R 4 combined is at least four; and

(2) R 5 and R 6 are each independently selected from the group consisting of alkyl, cycloalkyl, partially or fully deuterated variants thereof, and combinations thereof; at least one of R 3 and R 4 contain at least one deuterium; and total number of carbons in R 5 and R 6 combined is at least four.

12 . The compound of claim 1 , wherein R 3 , R 4 , R 5 , and R 6 are each independently selected from the group consisting of hydrogen, deuterium, methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, cyclopentyl, cyclohexyl, and combinations thereof.

13 . The compound of claim 1 , wherein the compound has a structure according to Formula V:

wherein R is selected from the group consisting of alkyl, cycloalkyl, its partially or fully deuterated variants thereof, and combinations thereof.

14 . The compound of claim 13 , wherein R is selected from the group consisting of methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, pentyl, methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, cyclopentyl, cyclohexyl, partially or fully deuterated variants thereof, and combinations thereof.

15 . The compound of claim 13 , wherein X is O.

16 . The compound of claim 1 , wherein L A is selected from the group consisting of:

17 . The compound of claim 1 , wherein L B is selected from the group consisting of

18 . The compound of claim 1 , wherein the compound is selected from the group consisting of:

19 . A first device comprising a first organic light emitting device, the first organic light emitting device comprising:

an anode;

a cathode; and

an organic layer, disposed between the anode and the cathode, the organic layer comprising a compound having a structure according to Formula I:

wherein A 1 , A 2 , A 3 , A 4 , A 5 , A 6 , A 7 , and A 8 comprise carbon or nitrogen;

wherein at least one of A 1 , A 2 , A 3 , A 4 , A 5 , A 6 , A 7 , and A 8 is nitrogen;

wherein ring B is bonded to ring A through a C—C bond;

wherein the iridium is bonded to ring A through a Ir—C bond;

wherein X is O, S, or Se;

wherein R 1 and R 2 each independently represent mono-, di-, tetra-substitution, or no substitution;

wherein R′ and R″ each independently represent mono-, di-substitution, or no substitution;

wherein any adjacent substitutions in R′, R″, R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are optionally linked together to form a ring;

wherein R 1 , R 2 , R′, and R″ are each independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrite, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;

wherein R 3 , R 4 , R 5 , and R 6 are each independently selected from the group consisting of hydrogen, deuterium, alkyl, cycloalkyl, and combinations thereof;

wherein n is an integer from 1 to 3; and

wherein total number of carbons in at least one of the pairs R 3 and R 4 , and R 5 and R 6 is at least four.

20 .- 29 . (canceled)

30 . A formulation comprising the compound having a structure according to Formula I:

wherein A 1 , A 2 , A 3 , A 4 , A 5 , A 6 , R 7 , and A 8 comprise carbon or nitrogen;

wherein at least one of A 1 , A 2 , A 3 , A 4 , A 5 , A 6 , A 7 , and A 8 is nitrogen;

wherein ring B is bonded to ring A through a C—C bond;

wherein the iridium is bonded to ring A through a Ir—C bond;

wherein X is O, S, or Se;

wherein R 1 and R 2 each independently represent mono-, di-, tri-, tetra-substitution, or no substitution;

wherein R′ and R″ each independently represent mono-, di-substitution, or no substitution;

wherein any adjacent substitutions in R′, R″, R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are optionally linked together to form a ring;

wherein R 1 , R 2 , R′, and R″ are each 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 R 3 , R 4 , R 5 , and R 6 are each independently selected from the group consisting of hydrogen, deuterium, alkyl, cycloalkyl, and combinations thereof;

wherein n is an integer from 1 to 3; and

wherein total number of carbons in at least one of the pairs R 3 and R 4 , and R 5 and R 6 is at least four.