Organic electronic device with improved hole injection

• US 20050253503A1
• Filed: 05/11/2004
• Published: 11/17/2005
• Est. Priority Date: 05/11/2004
• Status: Active Grant

• Current Assignee: Pictiva Displays International Limited (f/k/a Dolya Holdco 5 Limited) (Key Patent Innovations Limited)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Inventors: Choong, Vi-En, Stegamat, Reza
• Granted Patent: US 7,550,915 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/14 Carrier transporting layers
• CPC Class Codes: H10K 85/1135 Polyethylene dioxythiophene [PEDOT]; Derivatives thereof
• CPC Class Codes: H10K 85/631 Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine

Abstract

In a first embodiment of the present invention, in order to increase the number of holes injected into the emissive layer, an intermixed layer is formed from the intermixing of the hole transport layer (“HTL”) and the emissive layer. The intermixed layer is between the HTL and the emissive layer of the OLED device. Alternatively, in a second embodiment of the present invention, in order to increase the number of holes injected into the emissive layer, a separate interlayer is incorporated within the OLED device. The interlayer is comprised of a hole transport material in which one of its components is at least partially replaced with one of the components of the emissive layer that is responsible for hole injection and transport. The separate interlayer is between the anode and the emissive layer of the OLED device. One or more intermediate layers may be present between the interlayer and the anode such as, for example, a HTL may be present between those two layers.

Claims

1. An OLED device, comprising:

a substrate;

an anode on said substrate;

a hole transport layer on said anode;

an intermixed layer on said hole transport layer;

an emissive layer on said intermixed layer; and

a cathode on said emissive layer,

wherein at least one of;

(1) a HTL solution that dries to form said hole transport layer includes a first surfactant; and

(2) an EL solution that dries to form said emissive layer includes a second surfactant, and

wherein said intermixed layer has a range of IPs between a highest IP of an adjacent layer on an anode-end and a lowest IP of an adjacent layer on an “

emissive layer”

-end.

2. The OLED device of claim 1 wherein said intermixed layer is formed by:

(1) the intermixing of said hole transport layer and said EL solution to produce an intermixed solution, and (2) the drying of said intermixed solution.

3. The OLED device of claim 1 wherein

said first surfactant reduces surface tension of said HTL solution, and

said second surfactant reduces surface tension of said EL solution.

4. The OLED device of claim 1 wherein

the presence of at least one of:

(1) said first surfactant in said HTL solution, and (2) said second surfactant in said EL solution increases a thickness of said intermixed layer.

5. The OLED device of claim 1 wherein

said first surfactant is any one of:

isoproponal alcohol, methanol, or triton; and

said second surfactant is sodium dodecylsulfate.

6. A method to fabricate an OLED device, comprising:

forming an anode on a substrate;

adding at least one of;

(1) a first surfactant to a HTL solution, and (2) a second surfactant to an EL solution;

forming a hole transport layer on said anode by depositing said HTL solution on said anode and allowing said HTL solution to dry;

depositing said EL solution on said hole transport layer, a portion of said EL solution dissolves a portion of said hole transport layer producing an intermixed solution; and

allowing said intermixed solution and said EL solution to dry to form;

(1) an intermixed layer on said hole transport layer and (2) an emissive layer on said intermixed layer,

wherein said intermixed layer has a range of IPs between a highest IP of an adjacent layer on an anode-end and a lowest IP of an adjacent layer on an “

emissive layer”

-end.

7. The method of claim 6 further comprising

forming a cathode on said emissive layer.

8. The method of claim 6 wherein

allowing said HTL solution to dry includes baking said HTL solution after it is deposited;

and

allowing said intermixed solution and said EL solution to dry includes baking said intermixed solution and said EL solution after said EL solution is deposited on said hole transport layer.

9. The method of claim 6 wherein

said first surfactant reduces surface tension of said HTL solution, and

said second surfactant reduces surface tension of said EL solution.

10. The method of claim 6 wherein

the presence of at least one of:

(1) said first surfactant in said HTL solution, and (2) said second surfactant in said EL solution increases an area of said intermixed layer.

11. The method of claim 6 wherein

said first surfactant is any one of:

isoproponal alcohol, methanol, or triton; and

said second surfactant is sodium dodecylsulfate.

12. An OLED device, comprising:

a substrate;

an anode on said substrate;

a hole transport layer on said anode;

an intermixed layer on said hole transport layer;

an emissive layer on said intermixed layer; and

a cathode on said emissive layer,

wherein said hole transport layer includes a plurality of first components, said intermixed layer includes a plurality of second components, and said emissive layer includes a plurality of third components, and wherein one of said plurality of first components is a particular one of said plurality of second components and a particular one of said plurality of third components,

wherein said intermixed layer has a range of IPs between a highest IP of an adjacent layer on an anode-end and a lowest IP of an adjacent layer on an “

emissive layer”

-end.

13. The OLED device of claim 12 wherein said particular one of said plurality of first components in said emissive layer and said intermixed layer increases a thickness of said intermixed layer.

14. The OLED device of claim 12 wherein said particular one of said plurality of first components is:

PSS, polythiophene, or polyethylenedioxythiophene.

15. A method to fabricate an OLED device, comprising:

forming an anode on a substrate;

adding a particular one of a plurality of first components of a HTL solution to an EL solution so that it is one of a plurality of second components of said EL solution;

forming a hole transport layer on said anode;

depositing said EL solution on said hole transport layer, a portion of said EL solution dissolves a portion of said hole transport layer producing an intermixed solution; and

allowing said intermixed solution and said EL solution to dry to form;

(1) an intermixed layer on said hole transport layer, and (2) an emissive layer on said intermixed layer,

wherein said intermixed layer has a range of IPs between a highest IP of an adjacent layer on an anode-end and a lowest IP of an adjacent layer on an “

emissive layer”

-end.

16. The method of claim 15 further comprising

forming a cathode on said emissive layer.

17. The method of claim 15 wherein adding said particular one of said plurality of first components to said EL solution increases a thickness of said intermixed layer.

18. The method of claim 15 wherein forming said hole transport layer includes depositing said HTL solution on said anode and allowing said HTL solution to dry.

19. The method of claim 15 wherein said particular one of said plurality of first components is:

PSS, polythiophene, or polyethylenedioxythiophene.

20. An OLED device, comprising:

a substrate;

an anode on said substrate;

a hole transport layer on said anode;

an intermixed layer on said hole transport layer;

an emissive layer on said intermixed layer; and

a cathode on said emissive layer,

wherein said hole transport layer is formed from a HTL solution that includes a first non-aqueous solvent, and said emissive layer is formed from an EL solution that includes a second non-aqueous solvent, and said intermixed layer is formed from an intermixed solution resulting from a portion of said EL solution dissolving a portion of said hole transport layer, and

wherein said intermixed layer has a range of IPs between a highest IP of an adjacent layer on an anode-end and a lowest IP of an adjacent layer on an “

emissive layer”

-end.

21. The OLED device of claim 20 wherein

said non-aqueous solvent is an organic solvent.

22. The OLED device of claim 20 wherein

said HTL solution includes a plurality of organic polymers, and said first non-aqueous solvent dissolves said plurality of organic polymers, and said second non-aqueous solvent only partially dissolves said plurality of organic polymers.

23. The OLED device of claim 20 wherein

using said second non-aqueous solvent that only partially dissolves said plurality of organic polymers of said hole transport layer increases a thickness of said intermixed layer.

24. The OLED device of claim 20 wherein

said first non-aqueous solvent is any one of:

methanol, ethanol, toluene, xylene, dimethylpropylene urea, hydrogen chloride, or chloroform; and

said second non-aqueous solvent is any one of;

toluene or xylene.

25. A method to fabricate an OLED device, comprising:

forming an anode on a substrate;

depositing a HTL solution on said anode, said HTL solution includes a first non-aqueous solvent;

allowing said HTL solution to dry to form a hole transport layer;

depositing an EL solution on said hole transport layer, said EL solution includes a second non-aqueous solvent, wherein a portion of said EL solution dissolves a portion of said hole transport layer resulting in an intermixed solution; and

allowing said intermixed solution and said EL solution to dry to form;

(1) an intermixed layer on said hole transport layer, and (2) an emissive layer on said intermixed layer,

wherein said intermixed layer has a range of IPs between a highest IP of an adjacent layer on an anode-end and a lowest IP of an adjacent layer on an “

emissive layer”

-end.

26. The method of claim 25 further comprising

forming a cathode on said emissive layer.

27. The method of claim 25 wherein said second non-aqueous solvent in said EL solution that dissolves said portion of said hole transport layer increases intermixing between said hole transport layer and said EL solution.

28. The method of claim 25 wherein

said first non-aqueous solvent is any one of:

methanol, ethanol, toluene, xylene, dimethylpropylene urea, hydrogen chloride, or chloroform; and

said second non-aqueous solvent is any one of;

toluene or xylene.

29. An OLED device, comprising:

a substrate;

an anode on said substrate;

a hole transport layer on said anode;

an intermixed layer on said hole transport layer;

an emissive layer on said intermixed layer; and

a cathode on said emissive layer,

wherein after said hole transport layer, said intermixed layer, and said emissive layer are formed, said layers are baked to increase an amount of intermixing between said hole transport layer and said emissive layer, and

wherein said intermixed layer has a range of IPs between a highest IP of an adjacent layer on an anode-end and a lowest IP of an adjacent layer on an “

emissive layer”

-end.

30. The OLED device of claim 29 wherein

said hole transport layer is formed after a HTL solution is deposited on said anode and said HTL solution is allowed to dry;

and

said intermixed layer and said emissive layer are formed after an EL solution is deposited on said hole transport layer, a portion of said EL solution dissolves a portion of said hole transport layer producing an intermixed solution, and said intermixed solution and said EL solution are allowed to dry.

31. The OLED device of claim 29 wherein

said layers are baked at a temperature between 50°

C. and 300°

C.; and

said layers are baked for a time between one minute and twenty-four hours.

32. The OLED device of claim 29 wherein

said layers are baked at a temperature between 130°

C. and 200°

C.; and

said layers are baked for a time between five minutes and one hour.

33. A method to fabricate an OLED device, comprising:

forming an anode on a substrate;

depositing a HTL solution on said anode;

allowing said HTL solution to dry to form a hole transport layer;

depositing an EL solution on said hole transport layer, a portion of said EL solution dissolves a portion of said hole transport layer producing an intermixed solution;

allowing said intermixed solution and said EL solution to dry to form;

(1) an intermixed layer on said hole transport layer, and (2) an emissive layer on said intermixed layer; and

after said intermixed solution and said EL solution are allowed to dry, baking said hole transport layer, said intermixed layer, and said emissive layer to increase an amount of intermixing between the hole transport layer and the emissive layer,

wherein said intermixed layer has a range of IPs between a highest IP of an adjacent layer on an anode-end and a lowest IP of an adjacent layer on an “

emissive layer”

-end.

34. The method of claim 33 wherein

said hole transport layer, said intermixed layer, and said emissive layer are baked at a temperature between 50°

C. and 300°

C.; and

said hole transport layer, said intermixed layer, and said emissive layer are baked for a time between one minute and twenty-four hours.

35. The method of claim 33 wherein

said hole transport layer, said intermixed layer, and said emissive layer are baked at a temperature between 130°

C. and 200°

C.; and

said hole transport layer, said intermixed layer, and said emissive layer are baked for a time between five minutes and one hour.

36. An OLED device, comprising:

a substrate;

an anode on said substrate;

an interlayer on said anode;

an emissive layer on said interlayer, wherein said emissive layer includes a plurality of first components, a particular one of said plurality of first components is responsible for hole injection and transport; and

a cathode on said emissive layer,

wherein said interlayer includes a plurality of second components and a particular one of said plurality of second components is said particular one of said plurality of first components that is responsible for hole injection and transport, and

wherein said interlayer has a range of IPs between a highest IP of an adjacent layer on an anode-end and a lowest IP of an adjacent layer on an “

emissive layer”

-end.

37. The OLED device of claim 36 further comprising

a hole transport layer between said anode and said interlayer.

38. The OLED device of claim 36 wherein said particular one of said plurality of first components that is responsible for hole injection and transport is amines.

39. The OLED device of claim 38 wherein said amines are triarylamines.

40. The OLED device of claim 36 wherein said interlayer includes a plurality of third components that are responsible for hole injection and transport, said particular one of said plurality of second components is directly linked to a particular one of said plurality of third components.

41. The OLED device of claim 36 wherein said interlayer includes a plurality of third components that are responsible for hole injection and transport, and wherein a main chain includes an aliphatic group between said particular one of said plurality of second components and a particular one of said plurality of third components, wherein said aliphatic group facilitates synthesis of said interlayer.

42. A method to fabricate an OLED device, comprising:

forming an anode on a substrate;

forming an interlayer on said anode;

forming an emissive layer on said interlayer, wherein said emissive layer includes a plurality of first components, a particular one of said plurality of first components is responsible for hole injection and transport;

forming a cathode on said emissive layer,

wherein said interlayer includes a plurality of second components, a particular one of said plurality of second components is said particular one of said plurality of first components that is responsible for hole injection and transport, and

wherein said interlayer has a range of IPs between a highest IP of an adjacent layer on an anode-end and a lowest IP of an adjacent layer on an “

emissive layer”

-end.

43. The method of claim 42 further comprising

prior to forming said interlayer, forming a hole transport layer on said anode.

44. The method of claim 42 wherein said particular one of said plurality of first components that is responsible for hole injection and transport is amines.

45. The method of claim 44 wherein said amines are triarylamines.

46. The method of claim 42 wherein said interlayer includes a plurality of third components that are responsible for hole injection and transport, wherein forming said interlayer includes

linking said particular one of said plurality of second components to a particular one of said plurality of third components.

47. The method of claim 42 wherein said interlayer includes a plurality of third components that are responsible for hole injection and transport, wherein forming said interlayer includes

incorporating an aliphatic group between said particular one of said plurality of second components and a particular one of said plurality of third components to facilitate synthesis of said interlayer.