Organic electroluminescent device

• US 7,239,081 B2
• Filed: 07/24/2003
• Issued: 07/03/2007
• Est. Priority Date: 08/09/2002
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Tsutsui, Tetsuo
• Primary Examiner(s): Santiago; Mariceli
• Application Number:
  US10/626,024
• Publication Number:
  US 20040150333A1
• Time in Patent Office: 1,440 Days
• Field of Search: 313/502, 313/503, 313/504, 313/506, 313/509, 313/512, 428/690, 428/917
• US Class Current: 313/503
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• 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 50/19 Tandem OLEDs
• CPC Class Codes: H10K 71/841 Applying alternating current [AC] during manufacturing or treatment
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

An organic EL device that has good yields and high reliability as well as high current efficiency is provided by introducing the new concept to the conventional organic EL device structure. An EL device comprising a first electrode 101, a second electrode 102, an electroluminescent layer 103, conductive particles 104, wherein conductive particles 104 are dispersed in the EL layer 103, is used. Current efficiency will be increased since conductive particles serve as the conventional charge generation layer. In addition, fabricating processes will become simplified and fabricating costs will be reduced because the conductive particles and the EL layer can be formed simultaneously.

Claims

1. An electroluminescent device comprising:

a first electrode;

a second electrode;

an electroluminescent layer that emits light by an application of a voltage;

a first insulating layer between the first electrode and the electroluminescent layer; and

a second insulating layer between the second electrode and the electroluminescent layer,

wherein conductive particles are dispersed in the electroluminescent layer, and

wherein the conductive particles are covered with an organic compound.

2. An electroluminescent device according to claim 1, wherein the electroluminescent layer comprises a bipolar characteristics.

3. An electroluminescent device according to claim 1, wherein the electroluminescent layer comprises a bipolar mixed layer in which an organic film having an electron transporting characteristics and an organic film having a hole transporting characteristics are mixed.

4. An electroluminescent device according to claim 1, wherein the electroluminescent layer contains a polymeric compound having at least one of a π

-conjugate system and a σ

-conjugate system and having a bipolar characteristics.

5. An electroluminescent device according to claim 1, wherein the conductive particles contain a material having a conductivity equal to or greater than 10⁻

10 S/m.

6. An electroluminescent device according to claim 1, wherein the conductive particles comprise metal particles having an average diameter of 2 to 50 nm.

7. An electroluminescent device according to claim 6, wherein the metal particles comprise at least one selected from the group consisting of gold, silver, and platinum.

8. An electroluminescent device according to claim 1, wherein the conductive particles comprise at least one selected from the group consisting of carbon particles, carbon particles that have undergone a surface treatment by use of a surfactant, carbon nanotubes, and fullerenes.

9. An electroluminescent device comprising:

a first electrode;

a second electrode;

an electroluminescent layer that emits light by an application of a voltage;

a first insulating layer between the first electrode and the electroluminescent layer; and

a second insulating layer between the second electrode and the electroluminescent layer,

wherein semiconductor particles are dispersed in the electroluminescent layer, and

wherein the semiconductor particles are covered with an organic compound.

10. An electroluminescent device according to claim 9, wherein the electroluminescent layer comprises a bipolar characteristics.

11. An electroluminescent device according to claim 9, wherein the electroluminescent layer comprises a bipolar mixed layer in which an organic film having an electron transporting characteristics and an organic film having a hole transporting characteristics are mixed.

12. An electroluminescent device according to claim 9, wherein the electroluminescent layer contains a polymeric compound having at least one of a π

-conjugate system and a σ

-conjugate system and having a bipolar characteristics.

13. An electroluminescent device according to claim 9, wherein the semiconductor particles has an average diameter of 2 to 50 nm.

14. An electroluminescent device according to claim 9, wherein the semiconductor particles comprise at least one selected from the group consisting of cadmium sulfide, selenium sulfide, zinc oxide, zinc sulfide, copper iodide, and an indium tin oxide.

15. An electroluminescent device comprising:

a first electrode;

a second electrode; and

an electroluminescent layer between the first electrode and the second electrode, wherein the electroluminescent layer emits light by an application of a voltage,

wherein conductive particles are dispersed in the electroluminescent layer, and

wherein the conductive particles are covered with an organic compound.

16. An electroluminescent device according to claim 15, wherein the electroluminescent layer comprises a bipolar characteristics.

17. An electroluminescent device according to claim 15, wherein the electroluminescent layer comprises a bipolar mixed layer in which an organic film having an electron transporting characteristics and an organic film having a hole transporting characteristics are mixed.

18. An electroluminescent device according to claim 15, wherein the electroluminescent layer contains a polymeric compound having at least one of a π

-conjugate system and a σ

-conjugate system and having a bipolar characteristics.

19. An electroluminescent device according to claim 15, wherein the conductive particles contain a material having a conductivity equal to or greater than 10⁻

10 S/m.

20. An electroluminescent device according to claim 15, wherein the conductive particles comprise metal particles having an average diameter of 2 to 50 nm.

21. An electroluminescent device according to claim 20, wherein the metal particles comprise at least one selected from the group consisting of gold, silver, and platinum.

22. An electroluminescent device according to claim 15, wherein the conductive particles comprise at least one selected from the group consisting of carbon particles, carbon particles that have undergone a surface treatment by use of a surfactant, carbon nanotubes, and fullerenes.

23. An electroluminescent device comprising:

a first electrode;

a second electrode; and

an electroluminescent layer between the first electrode and the second electrode, wherein the electroluminescent layer emits light by an application of a voltage,

wherein semiconductor particles are dispersed in the electroluminescent layer, and

wherein the semiconductor particles are covered with an organic compound.

24. An electroluminescent device according to claim 23, wherein the electroluminescent layer comprises a bipolar characteristics.

25. An electroluminescent device according to claim 23, wherein the electroluminescent layer comprises a bipolar mixed layer in which an organic film having an electron transporting characteristics and an organic film having a hole transporting characteristics are mixed.

26. An electroluminescent device according to claim 23, wherein the electroluminescent layer contains a polymeric compound having at least one of a π

-conjugate system and a σ

-conjugate system and having a bipolar characteristics.

27. An electroluminescent device according to claim 23, wherein the semiconductor particles has an average diameter of 2 to 50 nm.

28. An electroluminescent device according to claim 23, wherein the semiconductor particles comprise at least one selected from the group consisting of cadmium sulfide, selenium sulfide, zinc oxide, zinc sulfide, copper iodide, and an indium tin oxide.

29. An electroluminescent device comprising:

a first electrode;

a second electrode; and

an electroluminescent layer between the first electrode and the second electrode, wherein the electroluminescent layer emits light by an application of a voltage,

wherein ITO (indium tin oxide) particles are dispersed in the electroluminescent layer.

30. An electroluminescent device according to claim 29, wherein the electroluminescent layer comprises a bipolar characteristics.

31. An electroluminescent device according to claim 29, wherein the electroluminescent layer comprises a bipolar mixed layer in which an organic film having an electron transporting characteristics and an organic film having a hole transporting characteristics are mixed.

32. An electroluminescent device according to claim 29, wherein the electroluminescent layer contains a polymeric compound having at least one of a π

-conjugate system and a σ

-conjugate system and having a bipolar characteristics.

33. An electroluminescent device according to claim 29, wherein the ITO (indium tin oxide) particles are covered with a silane coupling agent.