Organic electroluminescent materials and devices

1. An organic light emitting device (OLED) comprising: an anode; a cathode; and an emissive layer disposed between the anode and the cathode, the emissive layer comprising a first host compound, a second host compound and a Pt complex, wherein the first host compound comprises a structure of

wherein:

X 1 -X 4 are each independently C or N, with at least one of X 1 -X 4 is N;

wherein R 1 represents zero, mono, or up to maximum allowed number of substitutions to its associated ring;

each of R 1 , R 2 , R 3 , R 4 , and R 5 is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;

at least one of R 1 , R 2 , R 3 , R 4 , and R 5 comprises a silyl or germyl group;

any two adjacent R 1 , R 2 , R 3 , R 4 , or R 5 can be joined or fused to form a ring; and

wherein R 2 and R 3 , or R 4 and R 5 , are joined together to comprise a carbazole group, or a 5λ2-benzo[d]benzo[4,5]imidazo[3,2-a]imidazole group;

wherein the second host compound comprises a two carbazole linked moiety; and

wherein the Pt complex is capable of emitting light at room temperature upon photo or electrical excitation.

2. The OLED of claim 1 , wherein the Pt complex is a phosphorescent emitter.

3. The OLED of claim 1 , wherein the Pt complex has a structure of

wherein:

rings A, B, C, and D each independently represents a 5-membered or 6-membered carbocyclic or heterocyclic ring;

R A , R B , R c , and R D each independently represents zero, mono, or up to maximum allowed number of substitutions to its associated ring;

L 1 , L 2 , and L 3 are each independently selected from the group consisting of a direct bond, BR, BRR′, NR, PR, O, S, Se, C═O, S═O, SO 2 , CR′R″, SiR′R″, GeR′R″, and combinations thereof;

n is 0 or 1, when n is 0, L 4 is not present, and when n is 1, L 4 is selected from the group consisting of a direct bond, BR, BRR′, NR, PR, O, S, Se, C═O, S═O, SO 2 , CR′R″, SiR′R″, GeR′R″, and combinations thereof;

each of R A , R B , R C , R D , R, R′, and R″ is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;

Z 1 , Z 2 , Z 3 and Z 4 are each independently C or N;

K 1 , K 2 , K 3 and K 4 are each independently a direct bond, O, or S, with at least two of them being direct bonds; and

any adjacent R A , R B , R C , R D , R, and R′ can be joined to form a ring.

4. The OLED of claim 1 , wherein the Pt complex has at least one ligand or part of the ligand if the ligand is more than bidentate selected from the group consisting of:

wherein each Y 1 to Y 13 are independently selected from the group consisting of carbon and nitrogen; wherein Y′ is selected from the group consisting of B R e , N R e , P R e , O, S, Se, C═O, S═O, SO 2 , CR e R f , SiR e R f , and GeR e R f ;

wherein R e and R f are optionally fused or joined to form a ring;

wherein each R a , R b , R c , and R d independently represents zero, mono, or up to a maximum allowed number of substitutions to its associated ring;

wherein each of R a , R b , R c , R d , R e and R f is independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, boryl, 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 R a , R b , R c , or R d can be fused or joined to form a ring or form a multidentate ligand.

5. The OLED of claim 1 , wherein the Pt complex is selected from the group consisting of:

wherein R E and R F each independently represent zero, mono, or up to maximum allowed number of substitutions to its associated ring; R E , R F , and R N are each independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.

6. The OLED of claim 1 , wherein each of R 1 , R 2 , R 3 , R 4 , and R 5 is independently a hydrogen or a substituent selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, boryl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof.

7. The OLED of claim 1 , wherein R 2 and R 3 or R 4 and R 5 are joined together to form a ring.

8. The OLED of claim 1 , wherein two of X 1 , X 2 , and X 3 are N, and one is C; or three of X 1 , X 2 , and X 3 are each N.

9. The OLED of claim 1 , wherein at least one of R 1 , R 2 , R 3 , R 4 , and R 5 comprises a chemical group selected from the group consisting of carbazole, dibenzofuran, dibenzothiophene, tetraphenylene, triazine, pyrimidine, pyridine, 5λ2-benzo[d]benzo[4,5]imidazo[3,2-a]imidazole, benzo[d]benzo[4,5]imidazo[2,1-b]oxazole, benzo[d]benzo[4,5]imidazo[2,1-b]thiazole, 5H-6λ2-indolo[2,3-b]indole, 6H-benzofuro[2,3-b]indole, 6H-benzo[4,5]thieno[2,3-b]indole, and aza variants thereof.

10. The OLED of claim 1 , wherein the first host compound is selected from the group consisting of:

wherein X 1 -X 40 are each independently C or N; R 6 -R 12 each independently represent zero, mono, or up to maximum allowed number of substitutions to its associated ring; each of R 6 -R 12 is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and any two substituents can be joined or fused to form a ring.

11. The OLED of claim 1 , wherein the first host compound is selected from the group consisting of:

wherein each Y A is independently selected from the group consisting of O, S, Se, and N—Ar:

wherein each Ar is selected from the group consisting of

12. The OLED of claim 1 , wherein the first host compound is selected from the group consisting of:

13. The OLED of claim 1 , wherein the second host compound is

wherein X 5 -X 20 are each independently C or N; and

each of R 6 , R 7 , R 8 , R 9 , R 10 , and R 11 can be independently a hydrogen or a substituent selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof.

14. The OLED of claim 1 , wherein the second host compound is selected from the group consisting of

15. The OLED of claim 1 , wherein the emissive layer comprises an additional compound, and the additional compound is also a co-host which comprises a chemical moiety selected from the group consisting of triphenylene, carbazole, indolocarbazole, dibenzothiphene, dibenzofuran, dibenzoselenophene, 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene, aza-triphenylene, aza-carbazole, aza-indolocarbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, and aza-(5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene).

16. A consumer product comprising an organic light-emitting device (OLED) according to claim 1 .

17. A compound selected from the group consisting of:

wherein X 1 -X 40 are each independently C or N; R 6 -R 12 each independently represent zero, mono, or up to maximum allowed number of substitutions to its associated ring; each of R 6 -R 12 is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and any two substituents can be joined or fused to form a ring.

18. The compound of claim 17 , wherein the compound is selected from the group consisting of:

wherein each Y A is independently selected from the group consisting of O, S, Se, and N—Ar:

wherein each Ar is selected from the group consisting of:

19. The compound of claim 17 , wherein the compound is selected from the group consisting of: