Organic electroluminescent element

• US 20070057630A1
• Filed: 09/14/2006
• Published: 03/15/2007
• Est. Priority Date: 09/15/2005
• Status: Active Grant

• Current Assignee: UDC Ireland Limited
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Nishita, Nobuhiro, Okada, Hisashi
• Granted Patent: US 7,839,078 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 2101/80 Composition varying spatially, e.g. having a spatial gradient
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/18 Carrier blocking layers
• CPC Class Codes: H10K 50/181 Electron blocking layers
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/346 comprising platinum
• CPC Class Codes: H10K 85/657 Polycyclic condensed heteroaromatic hydrocarbons
• CPC Class Codes: H10K 85/6572 comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

The present invention provides an organic electroluminescent element comprising a plurality of organic compound layers between a pair of electrodes and comprising at least a luminescent layer and a buffer layer adjacent to the luminescent layer, the luminescent layer comprising at least two host materials and at least one luminescent material, the buffer layer comprising at least one of the host materials and at least one dopant material having a charge trapping function.

Claims

1. An organic electroluminescent element comprising a plurality of organic compound layers between a pair of electrodes and comprising at least a luminescent layer and a buffer layer adjacent to the luminescent layer, wherein the luminescent layer comprises at least two host materials and at least one luminescent material, and the buffer layer comprises at least one of the host materials and at least one dopant material having a charge trapping function.

2. The organic electroluminescent element according to claim 1, wherein the plurality of the organic compound layer further comprises a charge transport layer containing a charge transport material and the charge transport material is not contained in the luminescent layer.

3. The organic electroluminescent element according to claim 1, wherein the luminescent material is a phosphorescent material.

4. The organic electroluminescent element according to claim 1, wherein the dopant material having a charge trapping function is a luminescent material.

5. The organic electroluminescent element according to claim 2, wherein the luminescent material is a phosphorescent material.

6. The organic electroluminescent element according to claim 2, wherein the dopant material having a charge trapping function is a luminescent material.

7. The organic electroluminescent element according to claim 3, wherein the dopant material having a charge trapping function is a luminescent material.

8. An organic electroluminescent element comprising a plurality of organic compound layers between a pair of electrodes and comprising at least a luminescent layer and a buffer layer adjacent to the luminescent layer, the luminescent layer comprising at least two host materials and at least one luminescent material, the buffer layer comprising a single host material and a single dopant material having a charge trapping function.

9. The organic electroluminescent element according to claim 8, wherein the plurality of organic compound layer further comprises a charge transport layer containing a charge transport material, and the transport material is not contained in the luminescent layer.

10. The organic electroluminescent element according to claim 8, wherein the luminescent material is a phosphorescent material.

11. The organic electroluminescent element according to claim 8, wherein the dopant material having a charge trapping function is a luminescent material.

12. The organic electroluminescent element according to claim 9, wherein the luminescent material is a phosphorescent material.

13. The organic electroluminescent element according to claim 9, wherein the dopant material having a charge trapping function is a luminescent material.

14. An organic electroluminescent element comprising a plurality of organic compound layers between a pair of electrodes and comprising at least a luminescent layer and a buffer layer adjacent to the luminescent layer, the luminescent layer comprising at least two host materials and at least one luminescent material, the buffer layer comprising at least one of the host materials and at least one dopant material having a charge trapping function, the buffer layer containing at least a material A and a host material B, the content ratio of the host material A in the buffer layer gradually increasing until the ratio of the host material A to the host material B is at least 1:

1 in the direction of thickness of the buffer layer from the electrode side to the luminescent layer side.

15. The organic electroluminescent element according to claim 14, wherein the organic compound layer comprises a charge transport layer containing a charge transport material and the charge transport material is not contained in the luminescent layer.

16. The organic electroluminescent element according to claim 14, wherein the luminescent material is a phosphorescent material.

17. The organic electroluminescent element according to claim 14, wherein the dopant material having charge trapping function is a luminescent material.

18. The organic electroluminescent element according to claim 15, wherein the luminescent material is a phosphorescent material.

19. The organic electroluminescent element according to claim 15, wherein the dopant material having charge trapping function is a luminescent material.

20. The organic electroluminescent element according to claim 16, wherein the dopant material having charge trapping function is a luminescent material.