Organic electroluminescence device and method of fabricating the same

• US 8,373,191 B2
• Filed: 07/27/2009
• Issued: 02/12/2013
• Est. Priority Date: 07/30/2008
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Ide, Nobuhiro, Tsuji, Hiroya, Ito, Norihiro, Matsuhisa, Yuko
• Primary Examiner(s): Wilson, Allan R
• Application Number:
  US12/737,552
• Publication Number:
  US 20110127561A1
• Time in Patent Office: 1,296 Days
• Field of Search: 257/40, 257/99, 257/E51.018, 438/82, 438/99
• US Class Current: 257/99
• CPC Class Codes: H10K 50/19 Tandem OLEDs
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/611 Charge transfer complexes
• CPC Class Codes: H10K 85/6572 comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole

Abstract

[Problem] The present invention aims to provide an electroluminescence device with an improved intermediate layer, for achieving a superior durability and sustainability performance thereof.

[Solution] The present invention refers to organic electroluminescence devices having a plurality of light emitting layers 4 between an anode 1 and a cathode 2 with the intermediate layer 3 being interposed between two of the light emitting layers. The intermediate layer 3 comprises one layer 3a selected from a group consisting of a charge transfer complex layer made of a charge transfer complex, a metal layer made of a metal having a work function of 3.7 eV or less, and a metal compound layer made of a compound of the metal; an electrically conductive material-containing light transmissive layer 3b; a charge transport organic material layer 3c formed of a charge transport organic material; and a hole injection material layer 3d formed of a hole injection material, which are superimposed in this order. The charge transport material layer 3c is formed to have a thickness in a range of 0.5 nm to 30 nm.

Claims

1. An organic electroluminescence device comprising:

an anode;

a cathode;

a plurality of light emitting layers being disposed between said anode and said cathode; and

an intermediate layer being disposed between said light emitting layers;

said intermediate layer comprising;

a charge transfer complex layer made of a charge transfer complex, a metal layer made of a metal having a work function of 3.7 eV or less, or a metal compound layer made of a compound of the metal having the work function of 3.7 eV or less;

a light transmissive layer containing an electrically conductive material;

a charge transport organic material layer formed of a charge transport organic material; and

a hole injection material layer formed of a hole injection material,

which are superimposed in this order;

wherein said charge transport organic material layer is formed to have a thickness in a range of 0.5 nm to 30 nm.

2. The organic electroluminescence device as set forth in claim 1, wherein said charge transport organic material layer is formed of an electron transport material.

3. The organic electroluminescence device as set forth in claim 1, wherein said charge transport organic material layer is formed of a hole transport material.

4. The organic electroluminescence device as set forth in claim 1, wherein said charge transport organic material layer is formed of either one of;

a mixture of a hole transport material and an electron transport material; and

a bipolar material.

5. The organic electroluminescence device as set forth in claim 1, wherein said light transmissive layer containing the electrically conductive material is formed of a layer selected from a group consisting of;

a layer made of at least one of a metal oxide and a metal nitride;

a laminate layer which is formed of a laminate containing a metal layer made of a metal and a metal oxide layer made of a metal oxide;

a mixture layer made of a mixture of a metal and a metal oxide; and

a metal layer made of a metal.

6. The organic electroluminescence device as set forth in claim 1, wherein said light transmissive layer containing the electrically conductive material is formed to exhibit a light transmission of 80% or more.

7. The organic electroluminescence device as set forth in claim 1, wherein said hole injection material layer is formed of either one of a p-dope layer and an acceptor material layer made of an acceptor material.

8. A process of fabricating the organic electroluminescence device as set forth in claim 1, wherein said intermediate layer is prepared by steps of:

forming said charge transfer complex layer made of the charge transfer complex, said metal layer made of the metal having the work function of 3.7 eV or less, or said metal compound layer made of the compound of the metal having the work function of 3.7 eV or less, on one of said light emitting layers;

forming said light transmissive layer containing the electrically conductive material on a surface of one of said charge transfer complex layer, said metal layer and said metal compound layer;

laminating said charge transport organic material layer on a surface of said light transmissive layer containing the electrically conductive material; and

forming said hole injection material layer made of the hole injection material, on a surface of said charge transport organic material layer.

9. The organic electroluminescence device as set forth in claim 2, wherein said light transmissive layer containing the electrically conductive material is formed of a layer selected from a group consisting of;

a layer made of at least one of a metal oxide and a metal nitride;

a laminate layer which is formed of a laminate containing a metal layer made of a metal and a metal oxide layer made of a metal oxide;

a mixture layer made of a mixture of a metal and a metal oxide; and

a metal layer made of a metal.

10. The organic electroluminescence device as set forth in claim 3, wherein said light transmissive layer containing the electrically conductive material is formed of a layer selected from a group consisting of;

a layer made of at least one of a metal oxide and a metal nitride;

a laminate layer which is formed of a laminate containing a metal layer made of a metal and a metal oxide layer made of a metal oxide;

a mixture layer made of a mixture of a metal and a metal oxide; and

a metal layer made of a metal.

11. The organic electroluminescence device as set forth in claim 4, wherein said light transmissive layer containing the electrically conductive material is formed of a layer selected from a group consisting of;

a layer made of at least one of a metal oxide and a metal nitride;

a laminate layer which is formed of a laminate containing a metal layer made of a metal and a metal oxide layer made of a metal oxide;

a mixture layer made of a mixture of a metal and a metal oxide; and

a metal layer made of a metal.

12. The organic electroluminescence device as set forth in claim 2, wherein said light transmissive layer containing the electrically conductive material is formed to exhibit a light transmission of 80% or more.

13. The organic electroluminescence device as set forth in claim 4, wherein said light transmissive layer containing the electrically conductive material is formed to exhibit a light transmission of 80% or more.

14. The organic electroluminescence device as set forth in claim 5, wherein said light transmissive layer containing the electrically conductive material is formed to exhibit a light transmission of 80% or more.

15. The organic electroluminescence device as set forth in claim 2, wherein said hole injection material layer is formed of either one of a p-dope layer and an acceptor material layer made of an acceptor material.

16. The organic electroluminescence device as set forth in claim 4, wherein said hole injection material layer is formed of either one of a p-dope layer and an acceptor material layer made of an acceptor material.

17. The organic electroluminescence device as set forth in claim 5, wherein said hole injection material layer is formed of either one of a p-dope layer and an acceptor material layer made of an acceptor material.

18. A process of fabricating the organic electroluminescence device as set forth in claim 2, wherein said intermediate layer is prepared by steps of:

forming said charge transfer complex layer made of the charge transfer complex, said metal layer made of the metal having the work function of 3.7 eV or less, or said metal compound layer made of the compound of the metal having the work function of 3.7 eV or less, on one of said light emitting layers;

forming said light transmissive layer containing the electrically conductive material on a surface of one of said charge transfer complex layer, said metal layer and said metal compound layer;

laminating said charge transport organic material layer on a surface of said light transmissive layer containing the electrically conductive material; and

forming said hole injection material layer made of the hole injection material, on a surface of said charge transport organic material layer.

19. A process of fabricating the organic electroluminescence device as set forth in claim 4, wherein said intermediate layer is prepared by steps of:

forming said charge transfer complex layer made of the charge transfer complex, said metal layer made of the metal having the work function of 3.7 eV or less, or said metal compound layer made of the compound of the metal having the work function of 3.7 eV or less, on one of said light emitting layers;

forming said light transmissive layer containing the electrically conductive material on a surface of one of said charge transfer complex layer, said metal layer and said metal compound layer;

laminating said charge transport organic material layer on a surface of said light transmissive layer containing the electrically conductive material; and

forming said hole injection material layer made of the hole injection material, on a surface of said charge transport organic material layer.

20. A process of fabricating the organic electroluminescence device as set forth in claim 5, wherein said intermediate layer is prepared by steps of:

forming said charge transfer complex layer made of the charge transfer complex, said metal layer made of the metal having the work function of 3.7 eV or less, or said metal compound layer made of the compound of the metal having the work function of 3.7 eV or less, on one of said light emitting layers;

forming said light transmissive layer containing the electrically conductive material on a surface of one of said charge transfer complex layer, said metal layer and said metal compound layer;

laminating said charge transport organic material layer on a surface of said light transmissive layer containing the electrically conductive material; and

forming said hole injection material layer made of the hole injection material, on a surface of said charge transport organic material layer.