Organic light emitting display device (OLED) having p-type charge generation layer (CGL) formed between emissions stack

Patent metadata

Field	Value
Publication number	US-10950812-B2
Application number	US-201615192487-A
Country	US
Kind code	B2
Filing date	Jun 24, 2016
Priority date	Nov 30, 2015
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

Discussed is an organic light emitting display device. The organic light emitting display device can include a first emission part, a second emission part on the first emission part, and a first P-type charge generation layer between the first emission part and the second emission part. The first emission part includes a first hole transport layer, a first emission layer, and a first electron transport layer. The second emission part includes a second hole transport layer, a second emission layer, and a second electron transport layer. The second hole transport layer and the first P-type charge generation layer are disposed adjacent to each other. The second hole transport layer includes a first material and a second material. The first material has an absolute value of a HOMO energy level which can be greater than an absolute value of a LUMO energy level of the first P-type charge generation layer.

First claim

What is claimed is:

1. An organic light emitting display device comprising:
a first emission part including a first hole transport layer, a first emission layer, and a first electron transport layer;
a second emission part on the first emission part, the second emission part including a second hole transport layer, a second emission layer, and a second electron transport layer; and
a first P-type charge generation layer between the first emission part and the second emission part,
wherein:
the second hole transport layer and the first P-type charge generation layer are disposed adjacent to each other,
the second hole transport layer comprises a combination of a first material and a second material that have two kinds of characteristics and mixed in the second hole transport layer,
an absolute value of a highest occupied molecular orbitals (HOMO) energy level of the first material being greater than an absolute value of a lowest unoccupied molecular orbitals (LUMO) energy level of the first P-type charge generation layer,
the first P-type charge generation layer does not include a dopant,
a thickness of the second hole transport layer is within a range of 5 nm to 10 nm,
a hole mobility of one of the first material and the second material is higher than a hole mobility of the first P-type charge generation layer,
a hole mobility of the second material mixed with the first material in the second hole transport layer is within a range of approximately 1×10 −2 cm 2 /Vs to 1×10 −4 cm 2 /Vs, and
the first and second materials of the second hole transport layer include a starburst amine group.

2. The organic light emitting display device of claim 1 , wherein a difference between the absolute value of the HOMO energy level of the second hole transport layer and the absolute value of the LUMO energy level of the first P-type charge generation layer is within a range of approximately 0.1 eV to 0.3 eV.

3. The organic light emitting display device of claim 1 , wherein a volume ratio of the first material to the second material is approximately 5:5.

4. The organic light emitting display device of claim 1 , wherein the second hole transport layer includes a mixture of the first material and the second material in a single layer, and
wherein an absolute value of a HOMO energy level of the second hole transport layer is within a range of approximately 5.4 eV to 5.6 eV.

5. The organic light emitting display device of claim 1 , further comprising:
a third emission part on the second emission part, the third emission part including a third hole transport layer, a fourth hole transport layer, a third emission layer, and a third electron transport layer; and
a second P-type charge generation layer between the second emission part and the third emission part.

6. The organic light emitting display device of claim 5 , wherein the second P-type charge generation layer does not include a dopant.

7. The organic light emitting display device of claim 5 , wherein an absolute value of a HOMO energy level of the third hole transport layer and an absolute value of a HOMO energy level of the fourth hole transport layer each are greater than an absolute value of a LUMO energy level of the second P-type charge generation layer.

8. The organic light emitting display device of claim 5 , wherein:
a difference between the absolute value of the HOMO energy level of the third hole transport layer and the absolute value of the LUMO energy level of the second P-type charge generation layer is within a range of approximately 0.1 eV to 0.3 eV, and
a difference between the absolute value of the HOMO energy level of the fourth hole transport layer and the absolute value of the LUMO energy level of the second P-type charge generation layer is within a range of approximately 0.1 eV to 0.3 eV.

9. The organic light emitting display device of claim 5 , wherein an absolute value of a triplet energy level of the fourth hole transport layer is within a range of approximately 2.5 eV to 3.0 eV.

10. The organic light emit display device of claim 5 , wherein a hole mobility of the third hole transport layer is higher than a hole mobility of the fourth hole transport layer.

11. The organic light emitting display device of claim 5 , wherein the third hole transport layer is disposed closer to the second P-type charge generation layer than the fourth hole transport layer.

12. The organic light emitting display device of claim 5 , wherein a ratio of a thickness of the third hole transport layer to a thickness of the fourth hole transport layer is within a range of approximately 7:3 to 8:2.

13. An organic light witting display device comprising:
a first emission part including a first hole transport layer, a first emission layer, and a first electron transport layer;
a second emission part on the first emission part, the second emission part including a second hole transport layer, a second emission layer, and a second electron transport layer, the second hole transport layer comprising a combination of a first material and a second material that have two kinds of characteristics and mixed in the second hole transport layer;
a third emission part on the second emission part, the third emission part including a third hole transport layer, a third emission layer, and a third electron transport layer;
a first P-type charge generation layer between the first emission part and the second emission part; and
a second P-type charge generation layer between the second emission part and the third emission part,
wherein:
the organic light emitting display device comprises a fourth hole transport layer on the third hole transport layer,
an absolute value of a highest occupied molecular orbitals (HOMO) energy level of the third hole transport layer and an absolute value of a HOMO energy level of the fourth hole transport layer are equal,
the first P-type charge generation layer does not include a dopant,
a thickness of the second hole transport layer is within a range of 5 nm to 10 nm,
a hole mobility of one of the first material and the second material is higher than a hole mobility of the first P-type charge generation layer,
a hole mobility of the second material mixed with the first material in the second hole transport layer is within a range of approximately 1×10 −2 cm 2 /Vs to 1×10 −4 cm 2 /Vs, and
the first and second materials of the second hole transport layer include a starburst amine group.

14. The organic light emitting display device of claim 13 , wherein the absolute value of the HOMO energy level of the third hole transport layer and the absolute value of the HOMO energy level of the fourth hole transport layer each are greater than an absolute value of a lowest unoccupied molecular orbitals (LUMO) energy level of the second P-type charge generation layer.

15. The organic light emitting display device of claim 13 , wherein:
a difference between the absolute value of the HOMO energy level of the third hole transport layer and an absolute value of a lowest unoccupied molecular orbitals (LUMO) energy level of the second P-type charge generation layer is within a range of 0.1 eV to 0.3 eV, and
a difference between the absolute value of the HOMO energy level of the fourth hole transport layer and the absolute value of the LUMO energy level of the second P-type charge generation layer is within a range of approximately 0.1 eV to 0.3 eV.

16. The organic light emitting display device of claim 13 , wherein a hole mobility of the third hole transport layer is higher than a hole mobility of the fourth hole transport layer.

Assignees

• Lg Display Co Ltd

Inventors

• Han Yoondeok
• Lee Jaeman
• Ahn Soyeon
• Choi Heedong
• Park Jungsoo

Classifications

• H10K50/11 Primary

  characterised by the electroluminescent [EL] layers · CPC title

• H10K59/32 Primary

  Stacked devices having two or more layers, each emitting at different wavelengths · CPC title

• H10K2101/40

  Interrelation of parameters between multiple constituent active layers or sublayers, e.g. HOMO values in adjacent layers · CPC title

• H10K2101/10

  Triplet emission · CPC title

• H01L51/5072

  Electricity · mapped topic