LIGHT-EMITTING LAYER AND LIGHT-EMITTING ELEMENT

• US 20120217486A1
• Filed: 02/27/2012
• Published: 08/30/2012
• Est. Priority Date: 02/28/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: TAKEMURA, Yasuhiko, YAMAZAKI, Shunpei
• Granted Patent: US 8,969,854 B2
• Time in Patent Office: Days
• US Class Current: 257/40
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H10K 2101/30 Highest occupied molecular orbital [HOMO], lowest unoccupied molecular orbital [LUMO] or Fermi energy values
• CPC Class Codes: H10K 2102/351 Thickness
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers

Abstract

To provide a highly efficient organic light-emitting element. An extremely thin layer (a monomolecular film or the like) containing an organic light-emitting material such as an iridium complex is provided between a layer of an n-type organic material (an organic material having a high electron-transport property) and a layer of a p-type organic material (an organic material having a high hole-transport property). In a structure described above, in a layer of the organic light-emitting material, electrons are injected from the LUMO of the n-type organic material to the LUMO of the organic light-emitting material, and holes are injected from the HOMO of the p-type organic material to the HOMO of the organic light-emitting material, whereby the organic light-emitting material is brought into an excited state and emits light.

Claims

1. An organic light-emitting layer comprising:

a layer of an n-type organic material;

a layer of a p-type organic material; and

a layer containing an organic light-emitting material molecule the number of molecules in the thickness direction of the layer containing the organic light-emitting material molecules is one to five, and

wherein the layer containing the organic light-emitting material molecule is interposed between the layer of the n-type organic material and the layer of the p-type organic material.

2. The organic light-emitting layer according to claim 1, wherein the organic light-emitting material molecule is an organic metal complex containing iridium.

3. A light-emitting element comprising the organic light-emitting layer according to claim 1.

4. The light-emitting element according to claim 3, comprising two or more light-emitting layers.

5. The light-emitting element according to claim 4, wherein the light-emitting layers emit light with different emission spectra.

6. The light-emitting element according to claim 3, comprising at least one of a hole-injection layer, a hole-transport layer, an electron-transport layer, an electron-injection layer, an electron-relay layer, and an intermediate layer.

7. The light-emitting element according to claim 3, wherein the light-emitting element is incorporated in one selected from the group consisting of a lighting device, a passive matrix display device and an active matrix display device.

8. An organic light-emitting layer comprising:

a layer of an n-type organic material;

a layer of a p-type organic material; and

a layer containing an organic light-emitting material molecule,

wherein the thickness of the layer containing the organic light-emitting material molecule is 1 nm to 10 nm,

wherein the layer containing the organic light-emitting material molecule is interposed between the layer of the n-type organic material and the layer of the p-type organic material, and

wherein the concentration of the organic light-emitting material molecule in the layer containing the organic light-emitting material molecule is 10 wt % to 50 wt %.

9. The organic light-emitting layer according to claim 8, wherein the organic light-emitting material molecule is an organic metal complex containing iridium.

10. A light-emitting element comprising the organic light-emitting layer according to claim 8.

11. The light-emitting element according to claim 10, comprising two or more light-emitting layers.

12. The light-emitting element according to claim 11, wherein the light-emitting layers emit light with different emission spectra.

13. The light-emitting element according to claim 10, comprising at least one of a hole-injection layer, a hole-transport layer, an electron-transport layer, an electron-injection layer, an electron-relay layer, and an intermediate layer.

14. The light-emitting element according to claim 10, wherein the light-emitting element is incorporated in one selected from the group consisting of a lighting device, a passive matrix display device and an active matrix display device.

15. A light-emitting element comprising:

an anode;

a cathode;

a layer of an n-type organic material;

a layer of a p-type organic material; and

a layer containing an organic light-emitting material molecule,

wherein the number of the molecules in the thickness direction of the layer containing an organic light-emitting material molecule is one to five,

wherein the layer containing the organic light-emitting material molecule is interposed between the layer of the n-type organic material and the layer of the p-type organic material,

wherein the layer of the n-type organic material is interposed between the cathode and the layer which contains the organic light-emitting material molecule, and

wherein the layer of the p-type organic material is interposed between the anode and the layer which contains the organic light-emitting material molecule.

16. The light-emitting element according to claim 15, wherein the organic light-emitting material molecule is an organic metal complex containing iridium.

17. The light-emitting element according to claim 15, wherein the light-emitting element comprises two or more organic light emitting layers, and wherein the emission spectrum of one of the organic light emitting layers is different from that of the other of the organic light emitting layers.

18. The light-emitting element according to claim 15, comprising at least one of a hole-injection layer, a hole-transport layer, an electron-transport layer, an electron-injection layer, an electron-relay layer, and an intermediate layer.

19. The light-emitting element according to claim 15, wherein the light-emitting element is incorporated in one selected from the group consisting of a lighting device, a passive matrix display device and an active matrix display device.

20. The light-emitting element according to claim 15, wherein both of an energy level of the triplet excited state of the n-type organic material and an energy level of the triplet excited state of the p-type organic material is larger than an energy level of the triplet excited state of the organic light-emitting material molecule.