Light-Emitting Component

• US 20100065825A1
• Filed: 04/13/2007
• Published: 03/18/2010
• Est. Priority Date: 04/19/2006
• Status: Active Grant

• Current Assignee: Novaled AG
• Original Assignee: Novaled AG
• Inventors: Blochwitz-Nimoth, Jan, Birnstock, Jan
• Granted Patent: US 8,569,743 B2
• Time in Patent Office: Days
• 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, 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 from a polymer material and a low-molecular layer of vacuum-deposited small molecules of an organic material that is depositable by means of vacuum evaporation, 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 approximately −

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

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

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

2. The device according to claim 1, characterized in that the light-emitting layer comprises a further low-molecular layer from vacuum-deposited small molecules of a further organic material that is separable by means of vacuum evaporation which is different from the organic material, wherein the small molecules of the further low-molecular layer are formed as:

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

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

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

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

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

2.0 V, preferably of maximum approximately −

2.2 V.

4. The device according to claim 1, characterized in that the acceptor molecules have a reduction potential versus Fc/Fc+ (ferrocene/ferrocenium redox couple) of minimum approximately 0 V, preferably of minimum approximately 0.24 V.

5. The device according to claim 1, characterized in that the donor molecules and/or the acceptor molecules have a molar mass between approximately 100 g/mol and approximately 2000 g/mol, preferably between approximately 200 g/mol and approximately 1000 g/mol.

6. The device according to claim 1, characterized in that the donor molecules are formed at least partially as W2(Xpp)4-molecules (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, characterized in that the acceptor molecules are at least partially formed as C14DCNQI-molecules (N,N′

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

8. The device according to claim 1, characterized in that the low-molecular and/or the further low-molecular layer have a layer thickness between 0.5 nm and approximately 20 nm, preferably between approximately 1 nm and approximately 10 nm and more preferably between 1 nm and approximately 5 nm.

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

10. The device according to claim 1, characterized in that the polymer layer has a layer thickness between approximately 20 nm and approximately 500 nm, preferably between approximately 40 nm and approximately 150 nm and more preferably between approximately 50 nm and approximately 100 nm.

11. The device according to claim 1, characterized in that the polymer layer is from a polymer material selected from the following group of polymer materials:

polyfluorenes, PPVs, polyspiros, polythiophenes or polyparaphenylenes.

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

13. The device according to claim 12, characterized in that the polymer hole injection layer has a layer thickness between approximately 20 nm and approximately 500 nm, preferably between approximately 40 nm and approximately 150 nm and more preferably between approximately 50 nm and approximately 100 nm.

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

15. The device according to claim 14, characterized in that 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, characterized in that the low-molecular organic electron transport layer has a doping concentration (donor material molecules:

matrix material molecules) between 1;

1000 and 1;

2, preferably between 1;

100 and 1;

5 and more preferably between 1;

100 and 1;

10.

17. The device according to claim 15, characterized in that the organic donor material has a molar mass between approximately 100 g/mol and approximately 2000 g/mol and preferred between approximately 200 g/mol and approximately 1000 g/mol.

18. The device according to at least any one of the claims 14, characterized in that the low-molecular organic electron transport layer has a layer thickness between approximately 10 nm and approximately 500 nm, preferably between approximately 20 nm and approximately 200 nm and more preferably between 20 nm and approximately 100 nm.

19. The device according to at least any one of the claims 15, characterized in that the low-molecular organic donor material is W₂(Xpp)₄.

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

21. The device according to claim 20, characterized in that the low-molecular organic blocking layer has a layer thickness between approximately 2 nm and approximately 50 nm, preferably between approximately 2 nm and approximately 30 nm and more preferably between approximately 5 nm and approximately 20 nm.

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

23. The device according to claim 22, characterized in that the polymer electron injection layer has a layer thickness between approximately 20 nm and approximately 500 nm, preferably between approximately 40 nm and approximately 150 nm and more preferably between approximately 50 nm and approximately 100 nm.

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

25. The device according to claim 24, characterized in that 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, characterized in that the low-molecular organic hole transport layer has a doping concentration (acceptor material molecules:

matrix material molecules) between 1;

1000 and 1;

2, preferably between 1;

100 and 1;

5 and more preferably between 1;

100 and 1;

10.

27. The device according to claim 25, characterized in that the organic acceptor material has a molar mass between approximately 100 g/mol and approximately 2000 g/mol and preferably between approximately 200 g/mol and approximately 1000 g/mol.

28. The device according to at least any one of the claims 24, characterized in that the low-molecular organic hole transport layer has a layer thickness between approximately 10 nm and approximately 500 nm, preferably between approximately 20 nm and approximately 200 nm and more preferably between approximately 20 nm and approximately 100 nm.

29. The device according to at least any one of the claims 25, characterized in that the low-molecular organic acceptor material is C4DCNQI.

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

31. The device according to claim 30, characterized in that the further low-molecular organic blocking layer has a layer thickness between approximately 2 nm and approximately 50 nm, preferably between approximately 2 nm and 30 nm and more preferably between approximately 5 nm and approximately 20 nm.

32. The device according to claim 1, characterized in that the arrangement of layers is formed 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”

), and 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, characterized in that the arrangement of layers with the substrate is transparent.

34. The device according to claim 1, characterized by a bottom contact and a top contact which are formed by means of the anode contact or the cathode contact and which are from one or several metals, a combination of a metal and a degenerate semiconductor material or a metal alloy.