White organic light emitting device

Patent metadata

Field	Value
Publication number	US-9997739-B2
Application number	US-201213623452-A
Country	US
Kind code	B2
Filing date	Sep 20, 2012
Priority date	Sep 20, 2011
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

Disclosed white organic light emitting device includes an anode and a cathode opposing each other; a charge generation layer interposed between the anode and the cathode; a first stack interposed between the anode and the charge generation layer, the first stack including a first hole transport layer and a first light emitting layer emitting blue fluorescent light; and a second stack interposed between the charge generation layer and the cathode, the second stack including a second hole transport layer and a second light emitting layer formed by doping one host with at least one of phosphorescent dopant, wherein a triplet energy level of the first hole transport layer is higher than a triplet energy level of the first light emitting layer, and a hole mobility of the first hole transport layer is 5.0×10 −4 cm 2 /s·V to 9.9×10 −3 cm 2 /s·V.

First claim

What is claimed is:

1. A white organic light emitting device comprising:
an anode and a cathode opposing each other on a substrate;
a charge generation layer interposed between the anode and the cathode;
a first stack interposed between the anode and the charge generation layer, the first stack including a first hole transport layer, a first blocking layer directly contacting the first hole transport layer, a first light emitting layer for emitting blue fluorescent light such that the first light emitting layer directly contacts the first blocking layer and comprises a first host and a fluorescent dopant in the first host, and a first electron transport layer directly contacting the first light emitting layer; and
a second stack interposed between the charge generation layer and the cathode, the second stack including a second hole transport layer, a second blocking layer directly contacting the second hole transport layer, a second light emitting layer directly contacting the second blocking layer and comprising a second host and at least one phosphorescent dopant doped in the second host, and a second electron transport layer directly contacting the second light emitting layer,
wherein the first light emitting layer and the second light emitting layer are single emitting layers in the first and second stack, respectively,
wherein a triplet energy level of the first blocking layer is 0.01 eV to 0.4 eV higher than a triplet energy level of the first host to prevent diffusion of excitons from the first light emitting layer,
wherein a triplet energy level of the first hole transport layer is less than the triplet energy level of the first blocking layer and greater than the triplet energy level of the first host, and
wherein a hole mobility of the first hole transport layer is 5.0×10 −4 cm 2 /s·V to 9.9×10 −3 cm 2 /s·V.

2. The white organic light emitting device according to claim 1 , wherein the triplet energy level of the first hole transport layer is 2.4 eV or more.

3. The white organic light emitting device according to claim 1 , wherein the phosphorescent dopant of the second light emitting layer comprises a yellow phosphorescent dopant and a green phosphorescent dopant.

4. The white organic light emitting device according to claim 1 , wherein the phosphorescent dopant of the second light emitting layer comprises a red phosphorescent dopant and a green phosphorescent dopant.

5. The white organic light emitting device according to claim 1 , wherein the phosphorescent dopant of the second light emitting layer comprises a yellowish green phosphorescent dopant.

6. The white organic light emitting device according to claim 1 , wherein the hole mobility of the first hole transport layer is 6.0×10 −4 cm 2 /s·V to 9.9×10 −3 cm 2 /s·V.

7. The white organic light emitting device according to claim 1 , wherein the hole mobility of the first hole transport layer is 6.0×10 −4 cm 2 /s·V to 5.0×10 −3 cm 2 /s·V.

8. A white organic light emitting device comprising:
an anode and a cathode that face each other on a substrate;
a charge generation layer interposed between the anode and the cathode; and
a first stack and a second stack interposed between the anode and the charge generation layer, and between the charge generation layer and the cathode, respectively,
wherein each stack comprises a hole transport layer, a blocking layer directly contacting the hole transport layer, a light emitting layer directly contacting the blocking layer, and an electron transport layer directly contacting the light emitting layer laminated in this order,
the light emitting layer of the first stack is a single blue fluorescent layer comprising a first host and a fluorescent dopant in the first host, and the light emitting layer of the second stack is a single phosphorescent layer a second host at least one phosphorescent dopant in the second host,
a triplet energy level of each blocking layer of the first and second stacks is 0.01 eV to 0.4 eV higher than a triplet energy level of the light emitting layer adjacent thereto layer to prevent diffusion of excitons from the respective light emitting layer adjacent thereto, the triplet energy level of each blocking layer of the first and second stacks is higher than a triplet energy level of the hole transport layer adjacent thereto,
wherein a triplet energy level of the first hole transport layer is less than the triplet energy level of the first blocking layer and greater than the triplet energy level of the first host, and
a hole mobility of the hole transport layer is 5.0×10 −4 cm 2 /s·V to 9.9×10 −3 cm 2 /s·V.

9. The white organic light emitting device according to claim 8 , wherein the triplet energy level of the hole transport layer of the first stack is higher than the triplet energy level of the light emitting layer of the first stack and is 2.4 eV or more.

10. The white organic light emitting device according to claim 8 , wherein the phosphorescent dopant comprises a yellow phosphorescent dopant and a green phosphorescent dopant.

11. The white organic light emitting device according to claim 8 , wherein the phosphorescent dopant comprises a red phosphorescent dopant and a green phosphorescent dopant.

12. The white organic light emitting device according to claim 8 , wherein the phosphorescent dopant comprises a yellowish green phosphorescent dopant.

13. The white organic light emitting device according to claim 8 , wherein the hole mobility of the first hole transport layer is 6.0×10 −4 cm 2 /s·V to 9.9×10 −3 cm 2 /s·V.

14. The white organic light emitting device according to claim 8 , wherein the hole mobility of the first hole transport layer is 6.0×10 −4 cm 2 /s·V to 5.0×10 −3 cm 2 /s·V.

15. The white organic light emitting device according to claim 14 , wherein a triplet energy level of the hole transport layer of the first stack is less than the triplet energy level of the blocking layer of the first stack and greater than the triplet energy level of the light emitting layer of the first stack.

16. The white organic light emitting device according to claim 8 , wherein a triplet energy level of the hole transport layer of the first stack is less than the triplet energy level of the blocking layer of the first stack and greater than the triplet energy level of the light emitting layer of the first stack.

Assignees

• Lg Display Co Ltd

Inventors

• Song Ki-Woog
• Pieh Sung-Hoon
• Ko Sung-Jae

Classifications

• H01L51/5004

  Electricity · mapped topic

• H01L51/5096

  Electricity · mapped topic

• H01L51/5278 Primary

  Electricity · mapped topic

• H01L51/5016

  Electricity · mapped topic

• H01L2251/55

  Electricity · mapped topic