Light-emitting element, light-emitting device, and electronic device

• US 8,901,814 B2
• Filed: 03/11/2013
• Issued: 12/02/2014
• Est. Priority Date: 07/06/2005
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Seo, Satoshi, Iwaki, Yuji
• Primary Examiner(s): Mai, Anh
• Assistant Examiner(s): Lee, Brenitra M
• Application Number:
  US13/792,770
• Publication Number:
  US 20130187536A1
• Time in Patent Office: 631 Days
• Field of Search: 313498-512
• US Class Current: 313/506
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/1007 Non-condensed systems
• CPC Class Codes: C09K 2211/1014 bridged by heteroatoms, e.g. N, P, Si or B
• CPC Class Codes: C09K 2211/1022 bridged by heteroatoms, e.g. N, P, Si or B
• CPC Class Codes: C09K 2211/1029 containing one nitrogen atom as the heteroatom
• CPC Class Codes: C09K 2211/1044 containing two nitrogen atoms as heteroatoms
• CPC Class Codes: C09K 2211/1059 containing three nitrogen atoms as heteroatoms
• CPC Class Codes: C09K 2211/185 of the platinum group, i.e. Os, Ir, Pt, Ru, Rh or Pd
• CPC Class Codes: H05B 33/12 Light sources with substantially two-dimensional radiating surfaces
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/14 Carrier transporting layers
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/636 comprising heteroaromatic hydrocarbons as substituents on the nitrogen atom

Abstract

It is an object to provide a light-emitting element which can reduce power consumption. A light-emitting element is provided, which includes a pair of electrodes and a light-emitting layer interposed between the pair of electrodes. The light-emitting layer includes at least a first layer and a second layer, each of the first layer and the second layer includes an emission center and a host material, the emission center is dispersed in the host material, a thickness of each of the first layer and the second layer is 1 nm or more and 10 nm or less, and the first layer is not in contact with the second layer.

Claims

1. A light-emitting element comprising:

a first electrode;

a second electrode;

a first layer between the first electrode and the second electrode, the first layer including a first substance dispersed in a first host material;

a second layer between the second electrode and the first layer, the second layer including a second substance dispersed in a second host material;

a third layer between the first layer and the second layer, the third layer containing a first material with a carrier transporting property;

a fourth layer between the first electrode and the first layer, the fourth layer containing a second material with a carrier transporting property;

a first carrier transporting layer between the first electrode and the fourth layer; and

a second carrier transporting layer between the second electrode and the second layer,

wherein the third layer is in direct contact with the first layer and the second layer,

wherein the first material is the same as the first host material, and

wherein a band gap of the second material is bigger than a band gap of a substance included in the first carrier transporting layer.

2. The light-emitting element according to claim 1,

wherein the first electrode is anode,

wherein the second electrode is cathode and is provided over the first electrode.

3. The light-emitting element according to claim 1,

wherein at least one of the first electrode and the second electrode has a light-transmitting property.

4. The light-emitting element according to claim 1,

wherein the second material is the same as the first material.

5. The light-emitting element according to claim 1,

wherein the first substance is the same as the second substance, and

wherein the first host material is the same as the second host material.

6. The light-emitting element according to claim 1,

wherein each of the first substance and the second substance is an organic material, and

wherein each of the first host material and the second host material is an organic material.

7. The light-emitting element according to claim 1,

wherein each of the first substance and the second substance is a phosphorescent material.

8. The light-emitting element according to claim 1, further comprising:

a fifth layer comprising an organic compound having hole transporting property and a metal compound, the fifth layer between the first carrier transporting layer and the first electrode.

9. A light-emitting device using the light-emitting element according to claim 1 as a pixel or a light source.

10. An electronic device using the light-emitting element according to claim 1 as a display portion or a light source.

11. A light-emitting element comprising:

a first electrode;

a second electrode;

a first layer between the first electrode and the second electrode, the first layer including a first substance dispersed in a first host material;

a second layer between the second electrode and the first layer, the second layer including a second substance dispersed in a second host material;

a third layer between the first layer and the second layer, the third layer containing a first material with a carrier transporting property; and

a fourth layer between the first electrode and the first layer, the fourth layer containing a second material with a carrier transporting property,

wherein the third layer is in direct contact with the first layer and the second layer, and

wherein the first host material, the second host material, and the first material are the same material.

12. The light-emitting element according to claim 11,

wherein the first electrode is anode,

wherein the second electrode is cathode and is provided over the first electrode.

13. The light-emitting element according to claim 11,

wherein at least one of the first electrode and the second electrode has a light-transmitting property.

14. The light-emitting element according to claim 11,

wherein the first substance is the same as the second substance.

15. The light-emitting element according to claim 11,

wherein each of the first substance and the second substance is an organic material, and

wherein each of the first host material and the second host material is an organic material.

16. The light-emitting element according to claim 11,

wherein each of the first substance and the second substance is a phosphorescent material.

17. The light-emitting element according to claim 11, further comprising:

a fifth layer comprising an organic compound having hole transporting property and a metal compound, the fifth layer between the fourth layer and the first electrode.

18. A light-emitting device using the light-emitting element according to claim 11 as a pixel or a light source.

19. An electronic device using the light-emitting element according to claim 11 as a display portion or a light source.

20. The light-emitting element according to claim 11, wherein the second material is the same as the first material.