Organic electroluminescent materials and devices

1. A composition comprising, a mixture of a first compound and a second compound;

wherein the first compound has a structure of Formula I:

wherein the second compound has a structure of Formula II:

wherein L 1 , L 2 , L 3 and L 4 are each independently selected from the group consisting of direct bond, alkyl, alkenyl, alkynyl, aryl, heteroaryl, and combinations thereof;

wherein G 1 and G 2 are each independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, alkyloxy, cycloalkyl, cycloalkoxyl, silyl, amino, benzene, biphenyl, terphenyl, naphthalene, triphenylene, pyrene, anthracene, phenanthrene, fluoranthene, fluorene, dibenzofuran, dibenzothiophene, dibenzoselenophene, carbazole, and combinations thereof;

wherein G 3 is selected from the group consisting of pyridine, pyramidine, pyrazine, triazine, quinoline, isoquinoline, quinazoline, quinoxaline, benzimidazole, aza-triphenylene, phenanthroline, aza-pyrene, aza-anthracene, aza-fluorene, aza-dibenzofuran, aza-dibenzothiophene, aza-dibenzoselenophene, aza-carbazole, and combinations thereof;

wherein G 4 is selected from the group consisting of hydrogen, deuterium, halogen, alkyl, alkyloxy, cycloalkyl, cycloalkoxyl, silyl, amino, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl and combinations thereof;

wherein G 3 is optionally further substituted with substituent selected from the group consisting of hydrogen, deuterium, halogen, alkyl, alkyloxy, cycloalkyl, cycloalkoxyl, silyl, amino, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl and combinations thereof;

wherein R 1 , R 2 , R 3 , R 4 , R 5 and R 6 each independently represents mono to maximum allowable substitutions, or no substitution; and

wherein R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkyloxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, and wherein any two adjacent substituents optionally join or fuse into a ring;

wherein (i) the first compound is selected from the group consisting of Specific First Compounds, (ii) the second compound is selected from the group consisting of Specific Second Compounds, or (iii) both;

wherein the Specific First Compounds are defined as the following compounds:

and

the Specific Second Compounds are defined as the following commpounds:

2. The composition of claim 1 , wherein the first compound has an evaporation temperature T 1 of 150 to 350° C.;

wherein the second compound has an evaporation temperature T 2 of 150 to 350° C.;

wherein absolute value of T 1 −T 2 is less than 20° C.;

wherein the first compound has a concentration C 1 in said mixture and a concentration C 2 in a film formed by evaporating the mixture in a vacuum deposition tool at a constant pressure between 1×10 −6 Torr to 1×10 −9 Torr, at a 2 Å/sec deposition rate on a surface positioned at a predefined distance away from the mixture being evaporated; and

wherein absolute value of (C 1 −C 2 )/C 1 is less than 0.05.

3. The composition of claim 1 , wherein the first compound has a vapor pressure of P 1 at T 1 at 1 atm, and the second compound has a vapor pressure of P 2 at T 2 at 1 atm; and

wherein the ratio of P 1 /P 2 is within the range of 0.90:1 to 1.10:1.

4. The composition of claim 1 , wherein the first compound has a first mass loss rate and the second compound has a second mass loss rate, wherein the ratio between the first mass loss rate and the second mass loss rate is within the range of 0.90:1 to 1.10:1.

5. The composition of claim 1 , wherein the mixture of the first compound and the second compound is selected from the group consisting of: (Compound HA4, Compound EB1), (Compound HA5, Compound EB1), (Compound HA6, Compound EB1), (Compound HA11, Compound EB1), (Compound HA17, Compound EB1), (Compound HA20, Compound EB1), (Compound HA22, Compound EB1) (Compound HA29, Compound EB1), (Compound HB14, Compound EB1), (Compound HB20, Compound EB1), (Compound HC2, Compound EB1), (Compound HC8, Compound EB1), (Compound HD3, Compound EB1) (Compound HE4, Compound EB1), (Compound HF5, Compound EB1), (Compound HA1, Compound EB7), (Compound HA4, Compound EB7), (Compound HA5, Compound EB7), (Compound HA6, Compound EB7), (Compound HA11, Compound EB7), (Compound HA17, Compound EB7), (Compound HA20, Compound EB7), (Compound HA22, Compound EB7) (Compound HA29, Compound EB7), (Compound HB14, Compound EB7), (Compound HB20, Compound EB7), (Compound HC2, Compound EB7), (Compound HC8, Compound EB7), (Compound HD3, Compound EB7) (Compound HE4, Compound EB7), (Compound HF5, Compound EB7), (Compound HA1, Compound EA1), (Compound HA4, Compound EB2), (Compound HA5, Compound EB8), (Compound HA6, Compound EB13), (Compound HA11, Compound EC1), (Compound HA17, Compound EC2), (Compound HA20, Compound EC9), (Compound HA22, Compound EC11) (Compound HA29, Compound EC12), (Compound HB14, Compound EC15),(Compound HB20, Compound EC16), (Compound HC2, Compound ED2), (Compound HC8, Compound ED5), (Compound HD3, Compound ED20), (Compound HE4, Compound ED23), and (Compound HF5, Compound EF5).

6. An organic light emitting device (OLED) comprising:

an anode;

a cathode; and

an organic layer, disposed between the anode and the cathode, comprising a composition of claim 1 .

7. The OLED of claim 6 , wherein the organic layer is an emissive layer and the first and second compounds in the mixture are co-hosts.

8. The OLED of claim 7 , wherein the organic layer further comprises a phosphorescent emissive dopant; wherein the 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, alkyloxy, 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 substituents of R a , R b , R c , and R d are optionally fused or joined to form a ring or form a multidentate ligand.

9. The OLED of claim 6 , wherein the organic layer is a blocking layer and the mixture is used as blocking materials in the organic layer.

10. The OLED of claim 6 , wherein the organic layer is a transporting layer and the mixture is used as transporting materials in the organic layer.

11. An organic light emitting device (OLED) comprising:

an anode;

a cathode; and

an electron blocking layer, disposed between the anode and the cathode, comprising a compound having a structure selected from the group consisting of:

12. The OLED of claim 6 , wherein the compound of Formula I has an evaporation temperature T 1 of 150 to 350° C.;

wherein the second compound has an evaporation temperature T 2 of 150 to 350° C.;

wherein absolute value of T 1 −T 2 is less than 20° C.;

wherein the first compound has a concentration C 1 in said mixture and a concentration C 2 in a film formed by evaporating the mixture in a vacuum deposition tool at a constant pressure between 1×10 −6 Torr to 1×10 −9 Torr, at a 2 Å/sec deposition rate on a surface positioned at a predefined distance away from the mixture being evaporated; and

wherein absolute value of (C 1 −C 2 )/C 1 is less than 0.05.

13. The OLED of claim 6 , wherein the compound of Formula I has a vapor pressure of P 1 at T 1 at 1 atm, and the second compound has a vapor pressure of P 2 at T 2 at 1 atm; and

wherein the ratio of P 1 /P 2 is within the range of 0.90:1 to 1.10:1.

14. The OLED of claim 6 , wherein the compound of Formula I has a first mass loss rate and the second compound has a second mass loss rate, wherein the ratio between the first mass loss rate and the second mass loss rate is within the range of 0.90:1 to 1.10:1.

15. The OLED of claim 11 , wherein the OLED further comprises an emissive layer;

wherein the emissive layer comprises a phosphorescent emissive dopant;

wherein the 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, alkyloxy, 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 substituents of R a , R b , R c , and R d are optionally fused or joined to form a ring or form a multidentate ligand.

16. The composition of claim 1 , wherein the first compound is selected from the group consisting of the Specific First Compounds.

17. The composition of claim 16 , wherein the second compound is selected from the group consisting of the Specific Second Compounds.

18. The composition of claim 1 , wherein the second compound is selected from the group consisting of the Specific Second Compounds.

19. The OLED of claim 6 , wherein the first compound has a vapor pressure of P 1 at T 1 at 1 atm, and the second compound has a vapor pressure of P 2 at T 2 at 1 atm; and

wherein the ratio of P 1 /P 2 is within the range of 0.90:1 to 1.10:1.