Light-emitting component

• US 7,986,090 B2
• Filed: 02/22/2006
• Issued: 07/26/2011
• Est. Priority Date: 03/15/2005
• Status: Active Grant

• Current Assignee: Novaled AG
• Original Assignee: Novaled AG
• Inventors: Birnstock, Jan, Pfeiffer, Martin, Murano, Sven, Schwartz, Gregor
• Primary Examiner(s): Patel; Nimeshkumar D
• Assistant Examiner(s): ZIMMERMAN, GLENN D
• Application Number:
  US11/908,632
• Publication Number:
  US 20090230844A1
• Time in Patent Office: 1,980 Days
• Field of Search: 313/504, 313/506, 428/690
• US Class Current: 313/504
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 71/30 Doping active layers, e.g. electron transporting layers
• CPC Class Codes: H10K 85/611 Charge transfer complexes
• 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

Abstract

The invention relates to a light-emitting component, in particular organic light-emitting diode, having an electrode and a counterelectrode and an organic region—arranged between the electrode and the counterelectrode—with a light-emitting organic region, which comprises an emission layer and a further emission layer and which, upon application of an electrical voltage to the electrode and the counterelectrode, is formed in a manner emitting light in a plurality of colour ranges in the visible spectral range, optionally through to white light, in which case the emission layer comprises a fluorescent emitter which emits light predominantly in the blue or in the blue-green spectral range; the further emission layer comprises one or a plurality of phosphorescent emitters emitting light predominantly in the non-blue spectral range; a triplet energy for an energy level of a triplet state of the fluorescent emitter in the emission layer is greater than a triplet energy for an energy level of a triplet state of the phosphorescent emitter in the further emission layer; and an at least 5% proportion of the light generated in the light-emitting organic region is formed in the visible spectral range as fluorescent light from singlet states of the fluorescent emitter in the emission layer.

Claims

1. A light-emitting component comprising an electrode and a counterelectrode and an organic region—

arranged between the electrode and the counterelectrode—

comprising a light-emitting organic region, which comprises an emission layer and a further emission layer and which, upon application of an electrical voltage to the electrode and the counterelectrode, emits light in a plurality of colour ranges in the visible spectral range, wherein;

the emission layer comprises a fluorescent emitter which emits light predominantly in the blue or in the blue-green spectral range; and

the further emission layer comprises one or a plurality of phosphorescent emitters emitting light predominantly in the non-blue spectral range;

a triplet energy for an energy level of a triplet state of the fluorescent emitter in the emission layer is greater than a triplet energy for an energy level of a triplet state of the phosphorescent emitter in the further emission layer; and

the light-emitting organic region delivers an at least 5% proportion of the light generated in the visible spectral range as fluorescent light from singlet states of the fluorescent emitter in the emission layer.

2. The light-emitting component according to claim 1, wherein the light-emitting organic region delivers an at least 10% proportion of the light generated in the visible spectral range as fluorescent light of the singlet states of the fluorescent emitter in the emission layer.

3. The light-emitting component according to claim 1, wherein light generated in the light-emitting organic region delivers an at least 15% proportion of in the visible spectral range as fluorescent light of the singlet states of the fluorescent emitter in the emission layer.

4. The light-emitting component according to claim 1, wherein the light-emitting organic region delivers an at least 20% proportion of the light generated in the visible spectral range as fluorescent light of the singlet states of the fluorescent emitter in the emission layer.

5. The light-emitting component according to claim 1, wherein the light-emitting organic region delivers an at least 25% proportion of the light generated in the visible spectral range as fluorescent light of the singlet states of the fluorescent emitter in the emission layer.

6. The light-emitting component according to claim 1, wherein the emission layer and the further emission layer adjoin one another.

7. The light-emitting component according to claim 1, wherein the emission layer and the further emission layer transport holes, and in that a distance between a surface of the emission layer which faces the electrode formed as a cathode and a surface of the cathode which faces the emission layer is less than a distance between a surface of the further emission layer which faces the cathode and a surface of the cathode which faces the further emission layer.

8. The light-emitting component according to claim 1, wherein the emission layer and the further emission layer transport electrons, and in that a distance between a surface of the emission layer which faces the counter electrode formed as an anode and a surface of the anode which faces the emission layer is less than a distance between a surface of the further emission layer which faces the anode and a surface of the anode which faces the further emission layer.

9. The light-emitting component according to claim 1, wherein:

the light-emitting organic region comprises another emission layer having one or a plurality of phosphorescent emitters emitting light predominantly in the non-blue spectral range;

the emission layer is arranged between the further emission layer and the other emission layer;

the further emission layer transports electrons, a distance between a surface of the further emission layer which faces the cathode and a surface of the cathode which faces the further emission layer being less than a distance between a surface of the emission layer which faces the cathode and a surface of the cathode which faces the emission layer, and also a distance between a surface of the other emission layer which faces the cathode and a surface of the cathode which faces the other emission layer; and

the other emission layer transports holes, a distance between a surface of the other emission layer which faces the anode and a surface of the anode which faces the other emission layer being less than a distance between a surface of the emission layer which faces the anode and a surface of the anode which faces the emission layer, and also a distance between a surface of the further emission layer which faces the anode and a surface of the anode which faces the further emission layer.

10. The light-emitting component according to claim 1, wherein a hole blocking layer is arranged between the emission layer and the cathode, the hole blocking layer transporting electrons and an organic material of the hole blocking layer having an HOMO level which is at least about 0.3 eV lower than an HOMO level of the fluorescent emitter in the emission layer.

11. The light-emitting component according claim 1, wherein an electron blocking layer is arranged between the emission layer and the anode, the electron blocking layer transporting holes and all organic material of the electron blocking layer having an LUMO level which is at least about 0.3 eV higher than an LUMO level of the fluorescent emitter in the emission layer.

12. The light-emitting component according to claim 10, wherein a minimum energy of singlet excitons and of triplet excitons in the hole blocking layer or in the electron blocking layer is greater than a minimum energy of singlet excitons and of triplet excitons in the emission layer.

13. The light-emitting component according to claim 9, wherein emission layer and/or the further emission layer and/or the other emission layer are formed in multilayer fashion.

14. The light-emitting component according to claim 1, wherein the emission layer has a thickness of between about 5 nm and about 50 nm.

15. The light-emitting component according to claim 1, wherein the light-emitting organic region emits white light, and the or all of the phosphorescent emitters in the further mission layer comprise emitters emitting light in the red, orange, or yellow spectral range.

16. The light-emitting component according to claim 1, wherein the light-emitting organic region emits white light, and the or all of the phosphorescent emitters in the further emission layer comprise emitters emitting light in the red, orange or green spectral range.

17. The light-emitting component according to claim 9, wherein the light-emitting organic region emits white light, and the or all of the phosphorescent emitters in the other emission layer comprise emitters emitting light in the red, orange, or yellow spectral range.

18. The light-emitting component according to claim 9, wherein the light-emitting organic region emits white light, and the or all of the phosphorescent emitters in the other emission layer comprise emitters emitting light in the red, orange or green spectral range.

19. The light-emitting component according to claim 1, wherein a respective doped organic layer is arranged between the organic light-emitting region and the electrode or between the organic light-emitting region and the counterelectrode.

20. The light-emitting component according to claim 19, wherein the respective doped organic layer comprises a layer which is p-doped with an acceptor material or a layer which is n-doped with a donor material.

21. The light-emitting component according to claim 1, wherein the fluorescent emitter in the emission layer comprises an organometallic compound or a complex compound with a metal having an ordinal number of less than about 40.

22. The light-emitting component according to claim 1, wherein the fluorescent emitter in the emission layer comprises an electron-attracting substituent selected from the group consisting of:

a) halogens

b) CN;

c) halogenated or cyano-substituted alkanes or alkenes;

d) halogenated or cyano-substituted aryl radicals; and

e) boryl radicals.

23. The light-emitting component according to claim 1, wherein the fluorescent emitter in the emission layer comprises an electron-donating substituent selected from the group consisting of:

a) alkyl radicals;

b) alkoxy radicals;

c) aryl radicals with or without substituents on the aryl; and

d) amino groups.

24. The light-emitting component according to claim 1, wherein the fluorescent emitter in the emission layer comprises a functional group having an electron acceptor property selected from the group consisting of:

a) oxadiazole;

b) triazole;

c) benzotliadiazoles;

d) benzinidazoles and N-aryl-benzinidazoles;

e) bipyridine;

f) cyanoviily;

g) quinolines;

h) quinoxalines;

i) triarylboryl;

j) silol units;

k) cyclooctatetraene;

l) quinoid structures and ketones, including quinoid thiophene derivatives;

m) pyrazolines;

n) peiltaaryl cyclopentadiene;

o) benzothiadiazoles;

p) oligo-para-phenyl with electron-attracting substituents; and

q) fluorenes and spiro-bifluorenes with electron-attracting substituents.

25. The light emitting component according to claim 1, wherein the fluorescent emitter in the emission layer comprises a functional group having an electron acceptor property selected from the group consisting of:

a) triarylaillines;

b) oligo-para-phenyl or oligo-meta-phenyl;

c) carbazoles;

d) fluorene or spiro-bifluorenes;

e) phenylene-vinylene units;

f) naphthalene;

g) anthracene;

h) peryleile;

i) pyrene; and

j) thiophene.