OLEDs utilizing multidentate ligand systems

• US 20050170207A1
• Filed: 06/03/2004
• Published: 08/04/2005
• Est. Priority Date: 02/03/2004
• Status: Active Grant

• Current Assignee: Universal Display Corporation
• Original Assignee: Universal Display Corporation
• Inventors: Ma, Bin, Kwong, Raymond, Walters, Robert, Brooks, Jason
• Granted Patent: US 7,332,232 B2
• Time in Patent Office: Days
• US Class Current: 428/690
• CPC Class Codes: C07F 15/0033 Iridium compounds
• CPC Class Codes: C07F 15/0073 Rhodium compounds
• CPC Class Codes: C07F 5/069 without C-aluminium linkages
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/1029 containing one nitrogen atom as the heteroatom
• CPC Class Codes: C09K 2211/185 of the platinum group, i.e. Os, Ir, Pt, Ru, Rh or Pd
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 85/311 Phthalocyanine
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/631 Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine
• CPC Class Codes: H10K 85/649 Aromatic compounds comprising a hetero atom
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

The present invention relates to efficient organic light emitting devices (OLEDs), and more specifically to phosphorescent organic materials used in such devices. More specifically, the present invention relates to materials with improved stability and efficiency when incorporated into an OLED.

Claims

1. An organic light emitting device comprising an anode, a cathode, and an organic layer disposed between the anode and the cathode, wherein the organic layer comprises a phosphorescent organometallic emissive material comprising

a transition metal, and

two or three bidentate ligands, wherein two or more of the bidentate ligands are covalently linked by a linking group,

wherein, the bidentate ligands are selected from

bidentate photoactive ligands, wherein each bidentate photoactive ligand is bound to the transition metal through a carbon-metal bond and a nitrogen-metal bond to form a cyclometallated ring, and

bidentate ancillary ligands,

wherein at least one of the bidentate ligands is a bidentate photoactive ligand.

2. The organic light emitting device of claim 1, wherein the linking group provides no π

-conjugation between the linked bidentate ligands.

58. The organic light emitting device of claim 1 wherein the transition metal is selected from the group consisting of Ir, Pt, Pd, Rh, Re, Os, Tl, Pb, Bi, In, Sn, Sb, Te, Au, and Ag.

59. The organic light emitting device of claim 1 wherein the transition metal is Ir.

3. An organic light emitting device comprising an anode, a cathode, and an organic layer disposed between the anode and the cathode, wherein the organic layer comprises an emissive material having the formula I

[X_a—

(L)_b]M  

 

(I)

wherein,

M is a transition metal having a molecular weight greater than 40;

X is a linking group that links two or more L, and is selected from the group consisting of —

(CR₂)_d—

, —

[O(CR₂)_e]O—

, or a group having the formula

wherein

A is —

(CR₂)_f—

, or -Z-(CR₂)_g—

;

Z is —

O—

, —

NR—

, or —

SiR₂—

;

B¹ is —

O—

, —

NR—

, —

CR═

CR—

, aryl, heteroaryl, cycloalkyl, or a heterocyclic group,

B² is

alkyl, aryl, heteroaryl, cycloalkyl, or a heterocyclic group;

each R is independently selected from H, alkyl, aralkyl, aryl and heteroaryl,

d is 1 to 6,

e is 1 to 6,

f is 1 to 4, and

g is 1 to 4;

L is a bidentate ligand selected from the group consisting of

(i) bidentate photoactive ligands having the formula II

wherein

the bidentate photoactive ligand is bound to the transition metal through a carbon-metal bond and a nitrogen-metal bond to form a cyclometallated ring,

Y is N or C,

the dotted line represents an optional double bond,

R¹, R², R³ and R⁴ are independently selected from H, alkyl, or aryl, and additionally or alternatively, one or more of R¹ and R², R² and R³, and R³ and R⁴ together from independently a 5 or 6-member cyclic group, wherein said cyclic group is cycloalkyl, cycloheteroalkyl, aryl or heteroaryl; and

wherein said cyclic group is optionally substituted by one or more substituents Z;

each substituent Z is independently selected from the group consisting of alkyl, alkenyl, alkynyl, aralkyl, CN, CF₃, NR₂, NO₂, OR, halo, and aryl, and additionally, or alternatively, two Z groups on adjacent ring atoms form a fused 5- or 6-membered aromatic group, and

each R is independently selected from H, alkyl, aralkyl, aryl and heteroaryl; and

(ii) bidentate ancillary ligands,

a is 1 to 4;

b is 2 or 3; and

at least one L is selected from a bidentate photoactive ligand.

4. The organic light emitting device of claim 3, wherein the photoactive ligands are selected from compounds of the formula IV

5. The organic light emitting device of claim 3, wherein [X_a—

(L)_b] has the formula;

6. The organic light emitting device of claim 3, wherein the emissive material is a compound having the formula

7. The organic light emitting device of claim 3, wherein the emissive material is a compound having the formula

8. The organic light emitting device of claim 3, wherein the emissive material is a compound having the formula

37. The organic light emitting device of claim 3, wherein [X_a—

(L)_b] has the formula;

38. The organic light emitting device of claim 3, wherein [X_a—

(L)_b] has the formula;

39. The organic light emitting device of claim 3, wherein [X_a—

(L)_b] has the formula;

40. The organic light emitting device of claim 3, wherein the emissive material is a compound having the formula

45. The organic light emitting device of claim 3, wherein the emissive material is a compound having the formula:

47. The organic light emitting device of claim 3, wherein two or more L comprise a phenyl moiety and X is a linking group that links the two or more L via a covalent bond to the phenyl moiety in each of the two or more L.

48. The organic light emitting device of claim 3, wherein [X_a—

(L)_b] has the formula

49. The organic light emitting device of claim 48, wherein [X_a—

(L)_b] has the formula;

50. The organic light emitting device of claim 48, wherein [X_a—

(L)_b] has the formula;

60. The organic light emitting device of claim 3 wherein the transition metal is selected from the group consisting of Ir, Pt, Pd, Rh, Re, Os, Tl, Pb, Bi, In, Sn, Sb, Te, Au, and Ag.

61. The organic light emitting device of claim 3 wherein the transition metal is Ir.

9. A compound of the formula I

[X_a—

(L)_b]M  

 

(I)

wherein,

M is a transition metal having a molecular weight greater than 40;

X is a linking group that links two or more L, and is selected from the group consisting of —

(CR₂)_d—

, —

[O(CR₂)_e]O—

, or a group having the formula

wherein

A is —

(CR₂)_j, or -Z-(CR₂)_g—

;

Z is —

O—

, —

NR—

, or —

SiR₂—

;

B¹ is —

O—

, —

NR—

, —

CR═

CR—

, aryl, heteroaryl, cycloalkyl, or a heterocyclic group,

B² is

alkyl, aryl, heteroaryl, cycloalkyl, or a heterocyclic group;

each R is independently selected from H, alkyl, aralkyl, aryl and heteroaryl,

d is 1 to 6,

e is 1 to 6,

f is 1 to 4, and

g is 1 to 4;

L is a bidentate ligand selected from the group consisting of

(i) bidentate photoactive ligands having the formula II

wherein

the bidentate photoactive ligand is bound to the transition metal through a carbon-metal bond and a nitrogen-metal bond to form a cyclometallated ring,

Y is N or C,

the dotted line represents an optional double bond,

R¹ , R², R³ and R⁴ are independently selected from H, alkyl, or aryl, and additionally or alternatively, one or more of R¹ and R², R² and R³, and R³ and R⁴ together from independently a 5 or 6-member cyclic group, wherein said cyclic group is cycloalkyl, cycloheteroalkyl, aryl or heteroaryl; and

wherein said cyclic group is optionally substituted by one or more substituents Z;

each substituent Z is independently selected from the group consisting of alkyl, alkenyl, alkynyl, aralkyl, CN, CF₃, NR₂, NO₂, OR, halo, and aryl, and additionally, or alternatively, two Z groups on adjacent ring atoms form a fused 5- or 6-membered aromatic group, and

(ii) bidentate ancillary ligands,

each R is independently selected from H, alkyl, aralkyl, aryl and heteroaryl;

a is 1 to 4;

b is 2 or 3; and

at least one L is selected from a bidentate photoactive ligand.

10. The compound of claim 9, wherein the photoactive ligands are selected from compounds of the formula IV

11. The compound of claim 9, wherein [X_a—

(L)_b] has the formula;

12. The compound of claim 9, having the formula

13. The compound of claim 9, having the formula

14. The compound of claim 9, having the formula

41. The compound of claim 9, wherein [X_a—

(L)_b] has the formula;

42. The compound of claim 9, wherein [X_a—

(L)_b] has the formula;

43. The compound claim 9, wherein [X_a(L)_b] has the formula:

44. The compound of claim 9, having the formula:

46. The compound of claim 9 having the formula:

51. The compound of claim 9, wherein X is linked to each L via a covalent bond to a pyridyl moiety in each L.

52. The compound of claim 9, wherein [X_a—

(L)_b] has the formula;

53. The compound of claim 52, wherein [X_a—

(L)_b] has the formula;

54. The compound of claim 52, wherein [X_a—

(L)_b] has the formula;

62. The compound of claim 9 wherein the transition metal is selected from the group consisting of Ir, Pt, Pd, Rh, Re, Os, Tl, Pb, Bi, In, Sn, Sb, Te, Au, and Ag.

63. The compound of claim 9 wherein the transition metal is Ir.

15. An organic light emitting device comprising an anode, a cathode, and an organic layer disposed between the anode and the cathode, wherein the organic layer comprises a material of the formula VII

Al[Q_h(X)_iJ_j] 

 

(VII)

wherein

Q is a bidentate ligand of the formula VIII

wherein

ring B is a 5- or 6-membered aromatic group,

ring C is a 5- or 6-membered aromatic heterocyclic ring with at least one nitrogen atom that coordinates to the Al,

each R⁷ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, aralkyl, CN, CF₃, NR₂, NO₂, OR, halo, and aryl, and additionally, or alternatively, two R⁷ groups on adjacent ring atoms form a fused 5- or 6-membered aromatic group,

each R⁸ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, aralkyl, CN, CF₃, NR₂, NO₂, OR, halo, and aryl, and additionally, or alternatively, two R⁸ groups on adjacent ring atoms form a fused 5- or 6-membered aromatic group,

each R is independently selected from H, alkyl, aralkyl, aryl and heteroaryl,

x is 0 to 3, and

y is 0 to 3;

J is selected from monodentate ligands having the formula

wherein each R⁹ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, aralkyl, CN, CF₃, NO₂, O-alkyl, halo, and aryl, and z is 0 to 5;

X is a linking group that links two or more of the ligands Q or J, wherein at least one of the ligands linked by the linking group X is a bidentate ligand Q;

h is 2 or 3;

i is 1 to 4; and

j is 0 to 2.

16. The organic light emitting device of claim 15, wherein the linking group provides no π

-conjugation between the linked bidentate ligands.

17. The organic light emitting device of claim 15, wherein the linking group X is selected from the group consisting of

—

(CR₂)_d—

, —

[O(CR₂)_e]O—

, or a group having the formula

wherein

A is —

(CR₂)_f—

, or -Z-(CR₂)_g—

;

Z is —

O—

, —

NR—

, or —

SiR₂—

;

B¹ is —

O—

, —

NR—

, —

CR═

CR—

, aryl, heteroaryl, cycloalkyl, or a heterocyclic group,

B² is

alkyl, aryl, heteroaryl, cycloalkyl, or a heterocyclic group;

each R is independently selected from H, alkyl, aralkyl, aryl and heteroaryl,

d is 1 to 6,

e is 1 to 6,

f is 1 to 4, and

g is 1 to 4.

18. The organic light emitting device of claim 15, wherein the bidentate ligand Q has the formula

19. The organic light emitting device of claim 15, wherein j is 0 and h is 3.

20. The organic light emitting device of claim 15, wherein j is 1 and h is 2.

21. The organic light emitting device of claim 15, wherein [Q_h(X)_iJ_j] has the formula

22. The organic light emitting device of claim 15, wherein the organic layer comprises a material of the formula

23. A compound of the formula VII

Al[Q_h(X)_iJ_j] 

 

(VII)

wherein

Q is a bidentate ligand of the formula VIII

wherein

ring B is a 5- or 6-membered aromatic group,

ring C is a 5- or 6-membered aromatic heterocyclic ring with at least one nitrogen atom that coordinates to the Al,

each R⁷ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, aralkyl, CN, CF₃, NR₂, NO₂, OR, halo, and aryl, and additionally, or alternatively, two R⁷ groups on adjacent ring atoms form a fused 5- or 6-membered aromatic group,

each R⁸ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, aralkyl, CN, CF₃, NR₂, NO₂, OR, halo, and aryl, and additionally, or alternatively, two R⁸ groups on adjacent ring atoms form a fused 5- or 6-membered aromatic group,

each R is independently selected from H, alkyl, aralkyl, aryl and heteroaryl,

x is 0 to 3, and

y is 0 to 3;

J is a monodentate ligands having the formula

wherein each R⁹ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, aralkyl, CN, CF₃, NO₂, O-alkyl, halo, and aryl, and z is 0 to 5;

X is a linking group that links two or more of the ligands Q or J wherein at least one of the ligands linked by the linking group X is a bidentate ligand Q;

h is 2 or 3;

i is 1 to 4; and

j is 0 to 2.

24. The compound of claim 23, wherein the linking group provides no π

-conjugation between the linked bidentate ligands.

25. The compound of claim 23, wherein the linking group X is selected from the group consisting of

—

(CR₂)_d—

, —

[O(CR₂)_e]O—

, or a group having the formula

wherein

A is —

(CR₂)_f—

, or -Z-(CR₂)_g—

;

Z is —

O—

, —

NR—

, or —

SiR₂—

;

B¹ is —

O—

, —

NR—

, —

CR═

CR—

, aryl, heteroaryl, cycloalkyl, or a heterocyclic group,

B² is

alkyl, aryl, heteroaryl, cycloalkyl, or a heterocyclic group;

each R is independently selected from H, alkyl, aralkyl, aryl and heteroaryl,

d is 1 to 6,

e is 1 to 6,

f is 1 to 4, and

g is 1 to 4.

26. The compound of claim 23, wherein the bidentate ligand Q has the formula

27. The compound of claim 23, whereinj is 0 and h is 3.

28. The compound of claim 23, whereinj is 1 and h is 2.

29. The compound of claim 23, wherein [Q_h(X)_iJ_j] has the formula

30. The compound of claim 23, having the formula

31. An organic light emitting device comprising an anode, a cathode, and an organic layer disposed between the anode and the cathode, wherein the organic layer comprises a metal complex comprising:

a metal;

a first ligand bound to the metal, wherein the first ligand is a bidentate ligand;

a second ligand bound to the metal; and

a linking group that covalently links the first ligand and the second ligand,

wherein the linking group provides no π

-conjugation between the first ligand and the second ligand.

32. The organic light emitting device of claim 31, wherein the metal complex is a phosphorescent organometallic emissive material.

33. The organic light emitting device of claim 31, wherein the metal complex further comprises an additional bidentate ligand.

34. The organic light emitting device of claim 31, wherein the second ligand is a bidentate ligand.

35. The organic light emitting device of claim 31, wherein the second ligand is a monodentate ligand.

36. The organic light emitting device of claim 31, wherein the metal is aluminum.

55. An organic light emitting device comprising an anode, a cathode, and an organic layer disposed between the anode and the cathode, wherein the organic layer comprises a phosphorescent organometallic emissive material comprising a metal bound to two or three bidentate ligands, wherein two or more of the bidentate ligands are covalently linked by one or more linking groups.

56. The organic light emitting device of claim 55 wherein the organometallic emissive material comprises a compound represented by the formula

[X_a—

(L)_b]M

wherein M is a transition metal, L is a bidentate ligand, X is a linking group that links two or more L,

a is 1 to 4,

b is 2 or 3

wherein the bidentate ligands are selected from bidentate photoactive ligands, and bidentate ancillary ligands wherein at least one of the bidentate ligands is a bidentate photoactive ligand.

64. The organic light emitting device of claim 56 wherein the transition metal is selected from the group consisting of Ir, Pt, Pd, Rh, Re, Os, Tl, Pb, Bi, In, Sn, Sb, Te, Au, and Ag.

65. The organic light emitting device of claim 56 wherein the transition metal is Ir.

57. A compound of the formula

[X_a—

(L)_b]M

wherein M is a transition metal, L is a bidentate ligand, X is a linking group that links two or more L,

a is 1 to 4,

b is 2 or 3

wherein the bidentate ligands are selected from bidentate photoactive ligands, and bidentate ancillary ligands wherein at least one of the bidentate ligands is a bidentate photoactive ligand bound to the transition metal through a carbon-metal bond.

66. The compound of claim 57 wherein the transition metal is selected from the group consisting of Ir, Pt, Pd, Rh, Re, Os, Tl, Pb, Bi, In, Sn, Sb, Te, Au, and Ag.

67. The compound of claim 57 wherein the transition metal is Ir.