Organic electroluminescent materials and devices

1. A composition of materials comprising a first compound, wherein the first compound has a formula:

wherein X is selected from the group consisting of O, S, and Se;

wherein L 1 is selected from the group consisting of phenyl, biphenyl, terphenyl, pyridine, pyrimidine, and combinations thereof;

wherein L 2 and L 3 are each independently selected from the group consisting of a direct bond, phenyl, biphenyl, terphenyl, pyridine, pyrimidine, and combinations thereof;

wherein G 4 is selected from the group consisting of phenyl, biphenyl, terphenyl, naphthalene, phenanthrene, pyridine, pyrimidine, pyrazine, quinoline, isoquinoline, phenanthroline, and combinations thereof;

wherein G 2 , G 3 , and G 5 are each independently selected from the group consisting of phenyl, biphenyl, terphenyl, fluorene, naphthalene, phenanthrene, pyridine, pyrimidine, pyrazine, quinoline, isoquinoline, phenanthroline, aza-fluorene, and combinations thereof; and

wherein G 2 , G 3 , G 4 , and G 5 are each optionally further substituted with one or more unfused substituents selected from the group consisting of deuterium, alkyl, alkoxyl, cycloalkyl, cycloalkoxyl, halogen, nitro, nitrile, silyl, phenyl, biphenyl, terphenyl, pyridine, and combinations thereof.

2. The composition of claim 1 , wherein G 4 has the structure selected from the group consisting of:

3. The composition of claim 1 , wherein L 1 is selected from the group consisting of:

4. The composition of claim 1 , wherein G 2 , G 3 and G 5 are independently selected from the group consisting of:

wherein R B1 and R B2 are independently selected from a group consisting of hydrogen, deuterium, alkyl, cycloalkyl, alkoxyl, aryl, heteraryl, halogen, and combinations thereof; and

wherein R B1 and R B2 are optionally joined to form a ring.

5. The composition of claim 1 , wherein at least one of G 2 , G 3 , G 4 and G 5 is substituted with at least one fluorine atom.

6. The composition of claim 1 , wherein the first compound is selected from the group consisting of:

7. The composition of claim 1 , wherein the composition comprises a second compound;

wherein the second compound has the formula II:

wherein Ar 1 is selected from the group consisting of triphenylene, and aza-triphenylene;

wherein Ar 2 is selected from the group consisting of a direct bond, phenyl, biphenyl, terphenyl, naphthalene, pyridine, dibenzofuran, dibenzothiophene, dibenzoselenophene, aza-dibenzofuran, aza-dibenzothiophene, aza-dibenzoselenophene, and combinations thereof;

wherein Ar 3 is selected from the group consisting of benzene, biphenyl, terphenyl, naphthalene, pyridine, dibenzofuran, dibenzothiophene, dibenzoselenophene, aza-dibenzofuran, aza-dibenzothiophene, aza-dibenzoselenophene, carbazole, aza-carbazole, and combinations thereof; and

wherein Ar 1 , Ar 2 and Ar 3 are each, independently, optionally further substituted with one or more substitutions selected from the group consisting of deuterium, halogen, alkyl, aryl, heteroaryl, and combinations thereof.

8. The composition of claim 7 , wherein the second compound is selected from the group consisting of

wherein X is selected from the group consisting of O, S and Se;

wherein R 1 and R 4 each independently represents mono, di, or tri, substitution, or no substitution;

wherein R 2 , R 3 , R 5 , and R 6 each independently represents mono, di, tri, or tetra substitution, or no substitution; and

wherein R 1 to R 6 are each independently selected from the group consisting of hydrogen, deuterium, benzene, biphenyl, terphenyl, naphthalene, fluorene, triphenylene, phenanthrene, dibenzofuran, dibenzothiophene, carbazole and combinations thereof.

9. The composition of claim 7 , wherein the second compound is selected from the group consisting of

10. A composition comprising a mixture of a first compound and a second compound selected from the group consisting of:

11. The composition of claim 1 , wherein the composition comprises a second compound; wherein the second compound is a phosphorescent emissive Ir complex having at least one substituent selected from the group consisting of alkyl, cycloalkyl, partially or fully deuterated variants thereof, partially or fully fluorinated variants thereof, and combinations thereof.

12. 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, comprising A composition of materials comprising a first compound, wherein the first compound has a formula:

wherein X is selected from the group consisting of O, S, and Se;

wherein L 1 is selected from the group consisting of phenyl, biphenyl, terphenyl, pyridine, pyrimidine, and combinations thereof;

wherein L 2 and L 3 are each independently selected from the group consisting of a direct bond, phenyl, biphenyl, terphenyl, pyridine, pyrimidine, and combinations thereof;

wherein G 4 is selected from the group consisting of phenyl, biphenyl, terphenyl, naphthalene, phenanthrene, pyridine, pyrimidine, pyrazine, quinoline, isoquinoline, phenanthroline, and combinations thereof;

wherein G 2 , G 3 , and G 5 are each independently selected from the group consisting of phenyl, biphenyl, terphenyl, fluorene, naphthalene, phenanthrene, pyridine, pyrimidine, pyrazine, quinoline, isoquinoline, phenanthroline, aza-fluorene, and combinations thereof; and

wherein G 2 , G 3 , G 4 , and G 5 are each optionally further substituted with one or more unfused substituents selected from the group consisting of deuterium, alkyl, alkoxyl, cycloalkyl, cycloalkoxyl, halogen, nitro, nitrile, silyl, phenyl, biphenyl, terphenyl, pyridine, and combinations thereof.

13. The first device of claim 12 , wherein the organic layer is an emissive layer and the composition is a host.

14. The first device of claim 12 , wherein the organic layer further comprises a phosphorescent emissive dopant; wherein the phosphorescent emissive dopant is a transition metal complex having at least one ligand or part of the ligand if the ligand is more than bidentate selected from the group consisting of:

wherein each X 1 to X 13 are independently selected from the group consisting of carbon and nitrogen;

wherein X is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═O, S═O, SO 2 , CR′R″, SiR′R″, and GeR′R″;

wherein R′ and R″ are optionally fused or joined to form a ring;

wherein each R a , R b , R c , and R d may represent from mono substitution to the possible maximum number of substitution, or no substitution;

wherein R′, R″, R a , R b , R c , and R d 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; and

wherein any two adjacent substitutents of R a , R b , R c , and R d are optionally fused or joined to form a ring or form a multidentate ligand.

15. The first device of claim 14 , wherein at least one of R a , R b , R c , and R d is selected from the group consisting of alkyl, cycloalkyl, partially or fully deuterated variants thereof, partially or fully fluorinated variants thereof, and combinations thereof.

16. The first device of claim 12 , wherein the organic layer is a blocking layer and the composition is a blocking material in the organic layer, or the organic layer is an electron transporting layer and the composition is an electron transporting material in the organic layer.

17. The first device of claim 12 , wherein the first device is selected from the group consisting of a consumer product, an electronic component module, an organic light-emitting device, and a lighting panel.