LIGHT-EMITTING ELEMENT, DISPLAY DEVICE, AND ELECTRONIC APPLIANCE

• US 20110241007A1
• Filed: 06/16/2011
• Published: 10/06/2011
• Est. Priority Date: 08/04/2004
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: KUMAKI, Daisuke, SEO, Satoshi
• Granted Patent: US 8,618,574 B2
• Time in Patent Office: Days
• US Class Current: 257/59
• CPC Class Codes: H10K 2102/351 Thickness
• CPC Class Codes: H10K 50/15 Hole transporting layers
• CPC Class Codes: H10K 50/155 comprising dopants
• CPC Class Codes: H10K 50/157 between the light-emitting layer and the cathode
• CPC Class Codes: H10K 50/16 Electron transporting layers
• CPC Class Codes: H10K 50/165 comprising dopants
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays

Abstract

The present invention provides a light-emitting element having a structure in which the drive voltage is comparatively low and a light-emitting element in which the increase in the drive voltage over time is small. Further, the present invention provides a display device in which the drive voltage and the increase in the drive voltage over time are small and which can resist long-term use. A layer in contact with an electrode in a light-emitting element is a layer containing a P-type semiconductor or a hole-generating layer such as an organic compound layer containing a material having electron-accepting properties. The light-emitting layer is sandwiched between the hole-generating layers, and an electron-generating layer is sandwiched between the light-emitting layer and the hole-generating layer on a cathode side.

Claims

1. A light-emitting device comprising:

a substrate comprising an organic compound;

an anode over the substrate;

a first layer over the anode, the first layer generating holes;

a light emitting layer including a light emitting material over the first layer;

a second layer over the light emitting layer, the second layer generating electrons;

a third layer comprising metal oxide over the second layer, the third layer generating holes; and

a cathode being in contact with the third layer.

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

wherein the substrate comprises a material selected from the group consisting of polyimide, acrylic, polyethylene terephthalate, polycarbonate, polyacrylate, and polyethersulfone.

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

wherein the metal oxide is selected from the group consisting of vanadium oxide, molybdenum oxide, cobalt oxide, and nickel oxide.

12. A light-emitting device according to claim 1,

wherein the light-emitting device is a display device.

15. A light-emitting device according to claim 1,

wherein the substrate is a plastic substrate.

4. A light-emitting device comprising:

a substrate comprising an organic compound;

a semiconductor layer over the substrate;

a gate electrode adjacent to the semiconductor layer with an insulating layer interposed between the gate electrode and the semiconductor layer;

an anode over the substrate, the anode electrically connected to the semiconductor layer;

a first layer over the anode, the first layer generating holes;

a light emitting layer including a light emitting material over the first layer;

a second layer over the light emitting layer, the second layer generating electrons;

a third layer comprising metal oxide over the second layer, the third layer generating holes; and

a cathode being in contact with the third layer.

5. A light-emitting device according to claim 4,

wherein the substrate comprises a material selected from the group consisting of polyimide, acrylic, polyethylene terephthalate, polycarbonate, polyacrylate, and polyethersulfone.

6. A light-emitting device according to claim 4,

wherein the metal oxide is selected from the group consisting of vanadium oxide, molybdenum oxide, cobalt oxide, and nickel oxide.

7. A light-emitting device according to claim 4,

wherein the semiconductor layer comprises one selected from a group consisting of an amorphous semiconductor, a microcrystal semiconductor, and crystalline semiconductor layer.

13. A light-emitting device according to claim 4,

wherein the light-emitting device is a display device.

16. A light-emitting device according to claim 4,

wherein the substrate is a plastic substrate.

8. A light-emitting device comprising:

a substrate comprising an organic compound;

an anode over the substrate;

a first layer over the anode, the first layer generating holes;

a light emitting layer including a light emitting material over the first layer;

a second layer over the light emitting layer, the second layer generating electrons;

a third layer comprising metal oxide over the second layer, the third layer generating holes;

a cathode being in contact with the third layer;

a counter substrate over the cathode; and

a resin filled between the cathode and the counter substrate.

9. A light-emitting device according to claim 8,

wherein the substrate comprises a material selected from the group consisting of polyimide, acrylic, polyethylene terephthalate, polycarbonate, polyacrylate, and polyethersulfone.

10. A light-emitting device according to claim 8,

wherein the metal oxide is selected from the group consisting of vanadium oxide, molybdenum oxide, cobalt oxide, and nickel oxide.

11. A light-emitting device according to claim 8,

wherein the resin comprises one selected from a group consisting of polyvinyl chloride, acrylic, polyimide, an epoxy resin, a silicon resin, polyvinyl butyral, and ethylene vinylene acetate.

14. A light-emitting device according to claim 8,

wherein the light-emitting device is a display device.

17. A light-emitting device according to claim 8,

wherein the substrate is a plastic substrate.