Electroluminescent devices

• US 7,449,714 B2
• Filed: 04/05/2006
• Issued: 11/11/2008
• Est. Priority Date: 03/13/1998
• Status: Expired due to Fees

• Current Assignee: Cambridge Display Technology Limited (Sumitomo Chemical Company Limited)
• Original Assignee: Cambridge Display Technology Limited (Sumitomo Chemical Company Limited)
• Inventors: Burroughes, Jeremy Henley, Friend, Richard Henry, Lacey, David John, Devine, Peter, Bright, Christopher John
• Primary Examiner(s): TRINH, MICHAEL MANH
• Application Number:
  US11/398,258
• Publication Number:
  US 20060246613A1
• Time in Patent Office: 951 Days
• Field of Search: 257/40, 438/22, 438/28, 438/29, 438/99
• US Class Current: 257/40
• CPC Class Codes: C08G 2261/3142 fluorene-based, e.g. fluorene, indenofluorene, or spirobifluorene
• CPC Class Codes: C08G 2261/3162 Arylamines
• CPC Class Codes: C08G 2261/3246 containing nitrogen and sulfur as heteroatoms
• CPC Class Codes: H10K 2101/40 Interrelation of parameters between multiple constituent active layers or sublayers, e.g. HOMO values in adjacent layers
• CPC Class Codes: H10K 2101/90 Multiple hosts in the emissive layer
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/12 comprising dopants
• CPC Class Codes: H10K 50/15 Hole transporting layers
• CPC Class Codes: H10K 50/16 Electron transporting layers
• CPC Class Codes: H10K 71/12 using liquid deposition, e.g. spin coating
• CPC Class Codes: H10K 85/115 Polyfluorene; Derivatives thereof
• CPC Class Codes: H10K 85/151 Copolymers

Abstract

An electroluminescent device comprising: a first charge carrier injecting layer for injecting positive charge carriers; a second charge carrier injecting layer for injecting negative charge carriers; and a light-emissive layer located between the charge carrier injecting layers and comprising a mixture of: a first component for accepting positive charge carriers from the first charge carrier injecting layer; a second component for accepting negative charge carriers from the second charge carrier injecting layer; and a third, organic light-emissive component for generating light as a result of combination of charge carriers from the first and second components; at least one of the first, second and third components forming a type II semiconductor interface with another of the first, second and third components.

Claims

1. An electroluminescent device comprising:

an anode electrode layer;

a layer comprising doped PEDOT over the anode electrode layer;

a semiconducting region over the anode electrode layer, the semiconducting region comprising a first semiconducting organic layer comprising a first semiconducting organic component adjacent to a second semiconducting organic layer comprising a second semiconducting organic component, the first semiconducting layer being disposed between the layer of doped PEDOT and the second semiconducting layer; and

a cathode electrode layer over the semiconducting region,

wherein the first semiconducting organic layer is capable of hole transport and wherein the second semiconducting organic layer is light emissive.

2. An electroluminescent device according to claim 1, wherein the first semiconducting organic layer is TFB.

3. An electroluminescent device according to claim 1, wherein the second semiconducting organic layer comprises a blend of two or more organic components.

4. An electroluminescent device according to claim 3, wherein the second semiconducting organic layer comprises a blend of 5F8BT and TFB.

5. An electroluminescent device according to claim 1, wherein the second semiconducting organic layer comprises two or more components, wherein at least one of the components is capable of emitting light, and at least one of the other components is capable of hole transport or electron transport, and wherein the two or more components are present as functional chemical units of the same molecule.

6. An electroluminescent device according to claim 5, wherein the second semiconducting organic layer comprises a terpolymer of F8, F8BT and TFB.

7. An electroluminescent device according to any one of claims 1-6, wherein the PEDOT is doped with PSS.

8. A method for forming an electroluminescent device, which method comprises:

forming an anode electrode layer;

forming a layer comprising doped PEDOT over the anode electrode layer;

forming a semiconducting region over the anode electrode layer, the semiconducting region comprising a first semiconducting organic layer comprising a first semiconducting organic component adjacent to a second semiconducting organic layer comprising a second semiconducting organic component, the first semiconducting layer being disposed between the layer of doped PEDOT and the second semiconducting layer; and

forming a cathode electrode layer over the semiconducting region,

wherein the first semiconducting organic layer is capable of hole transport and wherein the second semiconducting organic layer is light emissive.

9. A method according to claim 8, wherein the first semiconducting polymer layer is TFB.

10. A method according to claim 8, wherein the second semiconducting organic layer comprises a blend of two or more polymers.

11. A method according to claim 10, wherein the second semiconducting organic layer comprises a blend of 5F8BT and TFB.

12. A method according to claim 8, wherein the second semiconducting organic layer comprises two or more components, wherein at least one of the components is capable of emitting light, and at least one of the other components is capable of hole transport or electron transport, and wherein the two or more components are present as functional chemical units of the same molecule.

13. A method according to claim 12, wherein the second semiconducting polymer layer comprise a terpolymer of F8, F8BT and TFB.

14. A method according to any one of claims 8 to 13, wherein the PEDOT is doped with PSS.