Organic electroluminescent device and display using same

• US 20070007882A1
• Filed: 06/16/2004
• Published: 01/11/2007
• Est. Priority Date: 07/02/2003
• Status: Active Grant

• Current Assignee: Idemitsu Kosan Company Limited
• Original Assignee: Idemitsu Kosan Company Limited
• Inventors: Fukuoka, Kenichi, Hosokawa, Chishio
• Granted Patent: US 8,007,924 B2
• Time in Patent Office: Days
• US Class Current: 313/503
• 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 85/626 containing more than one polycyclic condensed aromatic rings, e.g. bis-anthracene
• 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 85/655 comprising only sulfur as heteroatom
• CPC Class Codes: H10K 85/6565 Oxadiazole compounds
• CPC Class Codes: H10K 85/657 Polycyclic condensed heteroaromatic hydrocarbons
• CPC Class Codes: Y10T 428/24818 Knitted, with particular or differential bond sites or intersections

Abstract

An organic electroluminescent device including: at least two or more emitting layers (4), (8) between an anode (10) and a cathode (2), and an intermediate electrode layer (6) being interposed between emitting layers (4), (8), the intermediate electrode layer (6) being a single layer or a multilayer structure of a plurality of layers, at least one of the layers (6) including a semiconductive material having a resistivity of 0.001 to 10,000 Ω·cm. The device and a display using the same have a high efficiency and long life time.

Claims

1. An organic electroluminescent device comprising:

at least two or more emitting layers between an anode and a cathode, and an intermediate electrode layer being interposed between emitting layers, the intermediate electrode layer being a single layer or a multilayer structure of a plurality of layers, at least one of the layers comprising a semiconductive material having a resistivity of 0.001 to 10,000 Ω

·

cm.

2. The organic electroluminescent device according to claim 1, wherein the semiconductive material is a chalcogenide.

3. The organic electroluminescent device according to claim 1, wherein the semiconductive material comprises a chalcogenide and an alkali metal.

4. The organic electroluminescent device according to claim 1, wherein the semiconductive material is a conductive oxide.

5. The organic electroluminescent device according to claim 4, wherein the conductive oxide contains a transition metal.

6. The organic electroluminescent device according to claim 5, wherein the conductive oxide containing a transition metal is at least one oxide selected from the group of NbO_x, LaO_x, NdO_x, SmO_x, EuO_x, MoO_x, ReO_x, WO_x, OsO_x, IrO_x and PtO_x wherein x is 0.2 to 5.

7. The organic electroluminescent device according to claim 1, wherein the semiconductive material comprises an acceptor that is a conductive oxide containing a transition metal, and a donor that is an alkali metal and/or an alkaline earth metal.

8. The organic electroluminescent device according to claim 7, wherein the acceptor is at least one oxide selected from the group of Li_xTi₂O₄, Li_xV₂O₄, Er_xNbO₃, La_xTiO₃, Sr_xVO₃, Ca_xCrO₃, Sr_xCrO₃, A_xMoO₃ and AV₂O₅ wherein A is K, Cs, Rb, Sr, Na, Li or Ca, and x is 0.2 to 5.

9. The organic electroluminescent device according to claim 1, wherein the semiconductive material is a conductive organic radical salt represented by the following formula (1):

D_yA_z  

 

(1)

wherein D represents a molecule or an atom having a donor nature, A represents a molecule or an atom having an acceptor nature, y represents an integer of 1 to 5, and z represents an integer of 1 to 5.

10. The organic electroluminescent device according to claim 9, wherein D is a molecule represented by the following formulas (2) to (9):

wherein A¹s independently represent a carbon atom, a sulfur atom, a selenium atom or a tellurium atom, A²s independently represent a carbon atom, a sulfur atom, a selenium atom, a tellurium atom or an oxygen atom, R¹s independently represent a hydrogen atom or a C_{1 to 50} alkyl group, R²s independently represent a C_{1 to 50} alkyl group or a C_{1 to 50} thioalkyl group, and R³s independently represent a hydrogen atom, a C_{1 to 50} thioalkyl group or a C_{1 to 50} selenoalkyl group.

11. The organic electroluminescent device according to claim 9, wherein A is a molecule represented by the following formulas (10) to (13):

wherein Ar¹ represents the following organic groups that may be substituted with halogen,

wherein A³s independently represent an oxygen atom, a sulfur atom or a selenium atom, and A⁴s independently represent a sulfur atom or a selenium atom,

wherein A⁵s independently represent a carbon atom, a sulfur atom, a selenium atom, a tellurium atom or an oxygen atom, A⁶s independently represent a carbon atom, a sulfur atom, a selenium atom or a tellurium atom, Ms independently represent a nickel atom, a palladium atom, a platinum atom or a zinc atom, R⁴s independently represent a hydrogen atom, a halogen atom, a C_{1 to 50} alkyl group or a C_{1 to 50} alkoxy group.

12. The organic electroluminescent device according to claim 11, wherein D is an alkali metal or an alkaline earth metal.

24. The organic electroluminescent device according to claim 1, wherein the semiconductive material has a resistivity of not less than 0.001 Ω

·

cm but less than 100 Ω

·

cm.

26. The organic electroluminescent device according to claim 1, wherein the intermediate electrode layer is a bipolar charge injection layer.

27. The organic electroluminescent device according to claim 1, wherein the anode or the cathode is the same as the bipolar charge injection layer.

28. A display comprising a screen comprising the organic electroluminescent device according to claim 1.

13. An organic electroluminescent device comprising:

at least one or more emitting layers between an anode and a cathode,

the cathode comprising at least one metal oxide, and the cathode having a light transmittance of 80% or more.

14. The organic electroluminescent device according to claim 13, further comprising a sealing film made of a transparent material on the cathode, the sealing film having an area larger than the area of an emitting region formed of an overlap between the cathode and the anode.

15. The organic electroluminescent device according to claim 14, wherein the transparent material is an oxide, a nitride or an oxygen nitride of at least one element selected from the group of Si, Ge, Mg, Ta, Ti, Zn, Sn, In, Pb and Bi.

16. The organic electroluminescent device according to claim 14, wherein the transparent material is an oxide, a nitride or an oxygen nitride of at least one element selected from the group of Mo, V, Cr, W, Ni, Co, Mn, Ir, Pt, Pd, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Er and Yb.

17. The organic electroluminescent device according to claim 13, wherein the cathode comprises 2 to 20 wt % of a donor.

18. An organic electroluminescent device comprising:

one or more emitting layers between an anode and a cathode, and

bipolar charge injection layers being interposed between the anode and at least one of the emitting layers and between the cathode and at least one of the emitting layers.

19. The organic electroluminescent device according to claim 18, wherein the bipolar charge injection layers comprise at least one donor and at least one acceptor.

20. The organic electroluminescent device according to claim 19, wherein the acceptor is an oxide or a nitride of a transition metal.

21. The organic electroluminescent device according to claim 19, wherein the donor is an alkali metal and/or an alkaline earth metal.

22. The organic electroluminescent device according to claim 18, wherein the bipolar charge injection layers comprise a mixture of at least one element single substance selected from the group of Cs, Li, Na and K;

and at least one oxide selected from the group of MoO_x, VO_x, ReO_x, RuO_x, WO_x, ZnO_x, TiO_x, and CuO_x wherein x is 0.5 to 5.

23. The organic electroluminescent device according to claim 22, wherein the content of the element is 2 to 20 wt %.

25. An organic electroluminescent device comprising:

at least one or more emitting layers between an anode and a cathode,

the cathode comprising at least one donor and at least one acceptor comprising a metal oxide, and the cathode having a light transmittance of 80% or more.