Light-emitting component

• US 8,569,743 B2
• Filed: 04/13/2007
• Issued: 10/29/2013
• Est. Priority Date: 04/19/2006
• Status: Active Grant

• Current Assignee: Novaled AG
• Original Assignee: Novaled AG
• Inventors: Birnstock, Jan, Blochwitz-Nimoth, Jan
• Primary Examiner(s): CAMPBELL, SHAUN M
• Application Number:
  US12/297,506
• Publication Number:
  US 20100065825A1
• Time in Patent Office: 2,391 Days
• Field of Search: 257/40, 257/E51.022, 428688-703
• US Class Current: 257/40
• CPC Class Codes: H10K 2101/50 Oxidation-reduction potentials, e.g. excited state redox potentials
• CPC Class Codes: H10K 50/155 comprising dopants
• CPC Class Codes: H10K 50/165 comprising dopants
• CPC Class Codes: H10K 50/17 Carrier injection layers
• CPC Class Codes: H10K 50/171 Electron injection layers
• CPC Class Codes: H10K 50/18 Carrier blocking layers
• CPC Class Codes: H10K 85/1135 Polyethylene dioxythiophene [PEDOT]; Derivatives thereof
• CPC Class Codes: H10K 85/114 Poly-phenylenevinylene; Derivatives thereof
• CPC Class Codes: H10K 85/30 Coordination compounds
• CPC Class Codes: H10K 85/321 Metal complexes comprising a group IIIA element, e.g. Tris (8-hydroxyquinoline) gallium [Gaq3]
• CPC Class Codes: H10K 85/341 Transition metal complexes, e.g. Ru(II)polypyridine complexes H10K85/331 takes precedence
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/611 Charge transfer complexes

Abstract

The invention relates to a light-emitting device, in particular a light-emitting diode, with an arrangement of layers on a substrate, wherein the arrangement of layers has an anode contact and a cathode contact which are in electrical contact with a light-emitting layer stack arranged between the anode contact and the cathode contact which, on its part, comprises a polymer layer consisting of a polymer material and a low-molecular layer of vacuum-deposited small molecules of an organic material, and wherein the small molecules of the low-molecular layer are formed as donor molecules with an oxidation potential versus Fc/Fc⁺ (ferrocene/ferrocenium redox couple) of maximum approx. −1.5 V, if the low-molecular layer is arranged adjacent to the cathode contact, and as acceptor molecules with a reduction potential versus Fc/Fc⁺ (ferrocene/ferrocenium redox couple) of minimum approx. −0.3 V if the low-molecular layer is arranged adjacent to the anode contact.

Claims

1. A light-emitting device comprising an arrangement of layers on a substrate, wherein the arrangement of layers comprises an anode contact and a cathode contact which are in electrical contact with a light-emitting layer stack, wherein the light-emitting layer stack is arranged between the anode contact and the cathode contact, and the light-emitting layer stack comprises a polymer layer comprising a polymer material, and a first low-molecular layer of vacuum-deposited small molecules of a first organic material that is depositable by means of vacuum evaporation, wherein the first low-molecular layer is arranged adjacent to the cathode contact or the anode contact, and wherein the small molecules of the first low-molecular layer are:

donor molecules with a maximum oxidation potential versus Fc/Fc+ (ferrocene/ferrocenium redox couple) of approximately −

1.5 V, if the first low-molecular layer is arranged adjacent to the cathode contact, or

acceptor molecules with a minimum reduction potential versus Fc/Fc+ (ferrocene/ferrocenium redox couple) of approximately −

0.3 V, if the first low-molecular layer is arranged adjacent to the anode contact.

2. The device according to claim 1, wherein the light-emitting layer comprises a second low-molecular layer comprising vacuum-deposited small molecules of a second organic material that is separable by means of vacuum evaporation which is different from the first organic material, wherein the small molecules of the second low-molecular layer comprise:

acceptor molecules with a maximum oxidation potential versus Fc/Fc+ (ferrocene/ferrocenium redox couple) of approximately −

1.5 V, if the second low-molecular layer is arranged adjacent to the anode contact and the first low-molecular layer is arranged adjacent to the cathode contact, or

donor molecules with a minimum reduction potential versus Fc/Fc+ (ferrocene/ferrocenium redox couple) of approximately −

0.3 V, if the second low-molecular layer is arranged adjacent to the cathode contact and the first low-molecular layer is arranged adjacent to the anode contact.

3. The device according to claim 1, wherein the donor molecules have a maximum oxidation potential versus Fc/Fc+ (ferrocene/ferrocenium redox couple) of approximately −

2.0 V.

4. The device according to claim 1, wherein the acceptor molecules have a minimum reduction potential versus Fc/Fc+ (ferrocene/ferrocenium redox couple) of approximately 0 V.

5. The device according to claim 1, wherein the donor molecules or the acceptor molecules have a molar mass between approximately 100 g/mol and approximately 2000 g/mol.

6. The device according to claim 1, wherein the donor molecules comprise (tetrakis(1,2,3,3a,4,5,6,6a,7,8-decahydro-1,9,9b-triazaphenalenyl)ditungsten(II).

7. The device according to claim 1, wherein the acceptor molecules comprise (N,N′

-dicyano-2,3,5,6-tetrachloro-1,4-quinonediimine).

8. The device according to claim 2, wherein the first low-molecular or the second low-molecular layer have a layer thickness between approximately 0.5 nm and approximately 20 nm.

9. The device according to claim 1, wherein the polymer layer is a light-emitting and charge carrier transporting layer.

10. The device according to claim 1, wherein the polymer layer has a layer thickness between approximately 20 nm and approximately 500 nm.

11. The device according to claim 1, wherein the polymer layer comprises a polymer material selected from the following group of polymer materials:

polyfluorenes, poly(p-phenylene vinylene), polyspiros, polythiophenes, or polyparaphenylenes.

12. The device according to claim 1, wherein a polymer hole injection layer is arranged between the anode contact and the polymer layer, if the first low-molecular layer is arranged adjacent to the cathode contact.

13. The device according to claim 12, wherein the polymer hole injection layer has a layer thickness between approximately 50 nm and approximately 100 nm.

14. The device according to claim 1, wherein a low-molecular organic electron transport layer is arranged between the first low-molecular layer and the polymer layer, if the first low-molecular layer is arranged adjacent to the cathode contact.

15. The device according to claim 14, wherein the low-molecular organic electron transport layer comprises an organic matrix material which is electrically doped with a low-molecular organic donor material.

16. The device according to claim 15, wherein the low-molecular organic electron transport layer has a doping concentration (donor material molecules:

matrix material molecules) between 1;

1000 and 1;

2.

17. The device according to claim 15, wherein the organic donor material has a molar mass between approximately 100 g/mol and approximately 2000 g/mol.

18. The device according to claim 14, wherein the low-molecular organic electron transport layer has a layer thickness between approximately 10 nm and approximately 500 nm.

19. The device according to claim 15, wherein the low-molecular organic donor material comprises (tetrakis(1,2,3,3a,4,5,6,6a,7,8-decahydro-1,9,9b-triazaphenalenyl)ditungsten(II).

20. The device according claim 1, wherein a low-molecular organic blocking layer is arranged between the first low-molecular layer and the polymer layer, if the first low-molecular layer is arranged adjacent to the cathode contact.

21. The device according to claim 20, wherein the low-molecular organic blocking layer has a layer thickness between approximately 2 nm and approximately 50 nm.

22. The device according to claim 1, wherein a polymer electron injection layer is arranged between the cathode contact and the polymer layer, if the first low-molecular layer is arranged adjacent to the anode contact.

23. The device according to claim 22, wherein the polymer electron injection layer has a layer thickness between approximately 50 nm and approximately 100 nm.

24. The device according to claim 1, wherein a low-molecular organic hole transport layer is arranged between the first low-molecular layer and the polymer layer, if the first low-molecular layer is arranged adjacent to the anode contact.

25. The device according to claim 24, wherein the low-molecular organic hole transport layer comprises an organic matrix material which is electrically doped with a low-molecular organic acceptor material.

26. The device according to claim 25, wherein the low-molecular organic hole transport layer has a doping concentration (acceptor material molecules:

matrix material molecules) between 1;

1000 and 1;

2.

27. The device according to claim 25, wherein the organic acceptor material has a molar mass between approximately 200 g/mol and approximately 1000 g/mol.

28. The device according to claim 24, wherein the low-molecular organic hole transport layer has a layer thickness between approximately 10 nm and approximately 500 nm.

29. The device according to claim 25, wherein the low-molecular organic acceptor material is (N,N′

-dicyano-2,3,5,6-tetrachloro-1,4-quinonediimine).

30. The device according to claim 1, wherein a low-molecular organic blocking layer is arranged between the first low-molecular layer and the polymer layer, if the first low-molecular layer is arranged adjacent to the anode contact.

31. The device according to claim 30, wherein the low-molecular organic blocking layer has a layer thickness between approximately 2 nm and approximately 50 nm.

32. The device according to claim 1, wherein the arrangement of layers is arranged according to at least one configuration selected from the following group of configurations:

inverted configuration;

non-inverted configuration;

configuration having light which is generated in the light-emitting layer stack emitting away from the substrate (“

top-emission”

);

or configuration having light which is generated in the light-emitting layer stack emitting through the substrate (“

bottom emission”

).

33. The device according to claim 1, wherein the arrangement of layers and the substrate is transparent.

34. The device according to claim 1, wherein the anode contact or the cathode contact comprise:

one or several metals, a combination of a metal and a degenerate semiconductor material, or a metal alloy.