Organic light-emitting element and light-emitting device with the organic light-emitting element

• US 9,048,398 B2
• Filed: 06/02/2014
• Issued: 06/02/2015
• Est. Priority Date: 12/26/2002
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Hiroko, Seo, Satoshi
• Primary Examiner(s): HINES, ANNE M
• Application Number:
  US14/293,097
• Publication Number:
  US 20140264308A1
• Time in Patent Office: 365 Days
• Field of Search: 313498-512
• US Class Current: 1/1
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/121 for assisting energy transfer, e.g. sensitization
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 50/131 with spacer layers between the electroluminescent layers
• CPC Class Codes: H10K 50/15 Hole transporting layers
• CPC Class Codes: H10K 50/16 Electron transporting layers
• CPC Class Codes: H10K 50/17 Carrier injection layers
• CPC Class Codes: H10K 50/171 Electron injection layers
• CPC Class Codes: H10K 50/18 Carrier blocking layers
• CPC Class Codes: H10K 50/81 Anodes
• CPC Class Codes: H10K 50/82 Cathodes
• CPC Class Codes: H10K 50/828 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/30 Devices specially adapted for multicolour light emission
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/626 containing more than one polycyclic condensed aromatic rings, e.g. bis-anthracene
• CPC Class Codes: H10K 85/633 : comprising polycyclic condensed aromatic hydrocarbons as substituents on the nitrogen atom

Abstract

The present invention provides a white organic light-emitting element high in the emission efficiency. In particular, the invention provides a white organic light-emitting element that has an emission spectrum having peaks in the respective wavelength regions of red color, green color and blue color and is high in the emission efficiency. It is preferable to use an electron transport material between a first emission region and a second emission region and more preferable to use a hole block material.

Claims

1. A light-emitting device comprising:

an anode;

a hole-injection layer over and in contact with the anode;

a hole-transport layer over the hole-injection layer;

a first emission layer over and in contact with the hole-transport layer;

a spacing layer over and in contact with the first emission layer;

a second emission layer over and in contact with the spacing layer;

an electron-transport layer over and in contact with the second emission layer;

an electron-injection layer over the electron-transport layer; and

a cathode over and in contact with the electron-injection layer,

wherein the first emission layer comprises a first host material and a first fluorescent material,

wherein the second emission layer comprises a second host material and a second phosphorescent material,

wherein the first fluorescent material exhibits an emission peak in a region ranging from 400 nm to 500 nm, and

wherein the second phosphorescent material exhibits an emission peak in a region ranging from 560 nm to 700 nm.

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

wherein the second phosphorescent material is an iridium-based organometallic compound.

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

wherein a thickness of the spacing layer ranges from 1 nm to 30 nm.

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

wherein a thickness of the spacing layer ranges from 5 nm to 20 nm.

5. A display device comprising the light-emitting device according to claim 1.

6. A light-emitting device comprising:

an anode;

a hole-injection layer over and in contact with the anode;

a hole-transport layer over the hole-injection layer;

a first emission layer over and in contact with the hole-transport layer;

a spacing layer over and in contact with the first emission layer;

a second emission layer over and in contact with the spacing layer;

an electron-transport layer over and in contact with the second emission layer;

an electron-injection layer over the electron-transport layer; and

a cathode over and in contact with the electron-injection layer,

wherein the first emission layer comprises a first host material and a first fluorescent material,

wherein the second emission layer comprises a second host material and a second phosphorescent material,

wherein the first fluorescent material exhibits two emission peaks in a region ranging from 400 nm to 560 nm, and

wherein the second phosphorescent material exhibits an emission peak in a region ranging from 560 nm to 700 nm.

7. The light-emitting device according to claim 6,

wherein the second phosphorescent material is an iridium-based organometallic compound.

8. The light-emitting device according to claim 6,

wherein a thickness of the spacing layer ranges from 1 nm to 30 nm.

9. The light-emitting device according to claim 6,

wherein a thickness of the spacing layer ranges from 5 nm to 20 nm.

10. A display device comprising the light-emitting device according to claim 6.

11. A light-emitting device comprising:

an anode;

a hole-injection layer over and in contact with the anode;

a hole-transport layer over the hole-injection layer;

a first emission layer over and in contact with the hole-transport layer;

a spacing layer over and in contact with the first emission layer;

a second emission layer over and in contact with the spacing layer;

an electron-transport layer over and in contact with the second emission layer;

an electron-injection layer over the electron-transport layer; and

a cathode over and in contact with the electron-injection layer,

wherein the first emission layer comprises a first host material and a first dopant,

wherein the second emission layer comprises a second host material and a second dopant,

wherein the first dopant is a fluorescent material which exhibits an emission peaks in a region ranging from 400 nm to 500 nm, and

wherein the second dopant is configured so that its triplet excited state contributes to emission.

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

wherein the second dopant exhibits an emission peak in a region ranging from 560 nm to 700 nm.

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

wherein a thickness of the spacing layer ranges from 1 nm to 30 nm.

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

wherein a thickness of the spacing layer ranges from 5 nm to 20 nm.

15. A display device comprising the light-emitting device according to claim 11.