Light-emitting device using organometallic complex having a pyrazine skeleton

Patent metadata

Field	Value
Publication number	US-10764974-B2
Application number	US-201816157497-A
Country	US
Kind code	B2
Filing date	Oct 11, 2018
Priority date	Nov 30, 2006
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

Light-emitting elements having high emission efficiency and long lifetime can be provided. By forming light-emitting devices including the light-emitting elements, the light-emitting devices having low power consumption and long lifetime can be provided. A light-emitting device comprises a light-emitting element including a light-emitting layer between a first electrode and a second electrode. The light-emitting layer includes a first organic compound having a hole-transporting property, a second organic compound having an electron transporting property, and an organometallic complex. A central metal of the organometallic complex is an element belonging to one of Group 9 and Group 10, and a ligand of the organometallic complex is a ligand having a pyrazine skeleton.

First claim

What is claimed is:

1. A light-emitting device comprising:
a first electrode;
a hole transporting layer over the first electrode;
a light-emitting layer over the hole transporting layer;
an electron transporting layer over the light-emitting layer; and
a second electrode over the electron transporting layer,
wherein the light-emitting layer includes a first organic compound having a hole-transporting property, a second organic compound having an electron transporting property, and an organometallic complex,
wherein a central metal of the organometallic complex comprises an element belonging to one of Group 9 and Group 10,
wherein a ligand of the organometallic complex comprises a pyrazine skeleton, and
wherein an amount of the second organic compound is equal to or higher than an amount of the first organic compound.

2. The light-emitting device according to claim 1 , wherein the ligand comprises a 2-arylpyrazine derivative.

3. The light-emitting device according to claim 1 , wherein the ligand comprises a 2-phenylpyrazine derivative.

4. The light-emitting device according to claim 1 , wherein the ligand comprises a 2,5-diphenylpyrazine derivative.

5. The light-emitting device according to claim 1 , wherein the central metal comprises one of iridium and platinum, the first organic compound comprises one of an aromatic amine compound and a carbazole derivative, and the second organic compound comprises one of a heteroaromatic compound and a metal complex.

6. The light-emitting device according to claim 1 , wherein an amount of the organometallic complex in the light-emitting layer is greater than or equal to 1 percent by mass and less than or equal to 10 percent by mass.

7. The light-emitting device according to claim 1 , wherein a mass ratio of the second organic compound to the first organic compound is 1 to 20 inclusive.

8. The light-emitting device according to claim 1 ,
wherein a LUMO level of the organometallic complex is deeper than a LUMO level of the first organic compound and a LUMO level of the second organic compound by 0.2 eV or more, and
wherein a HOMO level of the organometallic complex is located between a HOMO level of the first organic compound and a HOMO level of the second organic compound.

9. A light-emitting device comprising:
a first electrode;
a hole transporting layer over the first electrode;
a light-emitting layer over the hole transporting layer;
an electron transporting layer over the light-emitting layer; and
a second electrode over the electron transporting layer,
wherein the light-emitting layer includes a first organic compound having a hole-transporting property, a second organic compound having an electron transporting property, and an organometallic complex,
wherein the organometallic complex is represented by a general formula (G1),

wherein Ar represents an arylene group, R 1 represents one of an alkyl group and an aryl group, R 2 represents one of hydrogen, an alkyl group and an aryl group, R 3 represents one of hydrogen and an alkyl group, M represents a central metal, and the central metal comprises an element belonging to one of Group 9 and Group 10, and
wherein an amount of the second organic compound is equal to or higher than an amount of the first organic compound.

10. The light-emitting device according to claim 9 ,
wherein the Ar is represented by a general formula (G2), and

wherein R 4 to R 7 each represent one of hydrogen, an alkyl group, a halogen group, a haloalkyl group, an alkoxy group, and an alkoxycarbonyl group.

11. The light-emitting device according to claim 9 ,
wherein the Ar is represented by a general formula (G2),

wherein the R 2 is represented by a general formula (G3), and

wherein R 4 to R 12 each represent one of hydrogen, an alkyl group, a halogen group, a haloalkyl group, an alkoxy group, and an alkoxycarbonyl group.

12. The light-emitting device according to claim 9 , wherein the central metal comprises one of iridium and platinum, the first organic compound comprises one of an aromatic amine compound and a carbazole derivative, and the second organic compound comprises one of a heteroaromatic compound and a metal complex.

13. The light-emitting device according to claim 9 , wherein an amount of the organometallic complex in the light-emitting layer is greater than or equal to 1 percent by mass and less than or equal to 10 percent by mass.

14. The light-emitting device according to claim 9 , wherein a mass ratio of the second organic compound to the first organic compound is 1 to 20 inclusive.

15. The light-emitting device according to claim 9 ,
wherein a LUMO level of the organometallic complex is deeper than a LUMO level of the first organic compound and a LUMO level of the second organic compound by 0.2 eV or more, and
wherein a HOMO level of the organometallic complex is located between a HOMO level of the first organic compound and a HOMO level of the second organic compound.

16. A light-emitting device comprising:
a first electrode;
a hole transporting layer over the first electrode;
a light-emitting layer over the hole transporting layer;
an electron transporting layer over the light-emitting layer; and
a second electrode over the electron transporting layer,
wherein the light-emitting layer includes a first organic compound having a hole-transporting property, a second organic compound having an electron transporting property, and an organometallic complex,
wherein the organometallic complex is represented by a general formula (G4),

wherein Ar represents an arylene group, R 1 represents one of an alkyl group and an aryl group, R 2 represents one of hydrogen, an alkyl group and an aryl group, R 3 represents one of hydrogen and an alkyl group, M represents a central metal, the central metal comprises an element belonging to one of Group 9 and Group 10, and L represents a monoanionic ligand,
wherein when the central metal comprises an element belonging to Group 9, n is 2 and when the central metal comprises an element belonging to Group 10, n is 1,
wherein an amount of the second organic compound is equal to or higher than an amount of the first organic compound.

17. The light-emitting device according to claim 16 ,
wherein the Ar is represented by a general formula (G5), and

wherein R 4 to R 7 each represent one of hydrogen, an alkyl group, a halogen group, a haloalkyl group, an alkoxy group, and an alkoxycarbonyl group.

18. The light-emitting device according to claim 16 ,
wherein the Ar is represented by a general formula (G5),

wherein the R 2 is represented by a general formula (G6), and

wherein R 4 to R 12 eac

Assignees

• Semiconductor Energy Lab

Inventors

• Ohsawa Nobuharu
• Inoue Hideko
• Seo Satoshi

Classifications

• H10K2101/10

  Triplet emission · CPC title

• C09K19/3452

  Pyrazine · CPC title

• H10K50/16 Primary

  Electron transporting layers · CPC title

• H10K85/141

  comprising aliphatic or olefinic chains, e.g. poly N-vinylcarbazol, PVC or PTFE · CPC title

• H10K50/15

  Hole transporting layers · CPC title