Organic light emitting display device having layer to control charge transfer

Patent metadata

Field	Value
Publication number	US-10978656-B2
Application number	US-202016852096-A
Country	US
Kind code	B2
Filing date	Apr 17, 2020
Priority date	Nov 19, 2015
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

An organic light emitting display device includes a plurality of pixels on a substrate, the plurality of pixels having a red subpixel, a green subpixel, and a blue subpixel; an anode on the substrate; a first hole transfer layer on the anode; a first emission layer on the first hole transfer layer in the red subpixel, the green subpixel, and the blue subpixel; a first electron transfer layer on the first emission layer; an N-type charge generation layer on the first electron transfer layer; a second hole transfer layer on the N-type charge generation layer; a second emission layer on the second hole transfer layer in the red subpixel, the green subpixel, and the blue subpixel; a second electron transfer layer on the second emission layer; and a cathode on the second electron transfer layer,

First claim

What is claimed is:

1. An organic light emitting display device, comprising:
a plurality of pixels on a substrate, the plurality of pixels having a red subpixel, a green subpixel, and a blue subpixel;
an anode on the substrate;
a first hole transfer layer on the anode;
a first emission layer on the first hole transfer layer in the red subpixel, the green subpixel, and the blue subpixel;
a first electron transfer layer on the first emission layer;
an N-type charge generation layer on the first electron transfer layer;
a second hole transfer layer on the N-type charge generation layer;
a second emission layer on the second hole transfer layer in the red subpixel, the green subpixel, and the blue subpixel;
a second electron transfer layer on the second emission layer; and
a cathode on the second electron transfer layer,
wherein a difference between a lowest unoccupied molecular orbital (LUMO) energy level of the first electron transfer layer and a LUMO energy level of the N-type charge generation layer is 0.50 eV to 1.00 eV.

2. The organic light emitting display device of claim 1 , wherein an absolute value of the LUMO energy level of the first electron transfer layer is within a range of 2.00 eV to 2.50 eV, and an absolute value of the LUMO energy level of the N-type charge generation layer is within a range of 2.90 eV to 3.20 eV.

3. The organic light emitting display device of claim 1 , wherein the second electron transfer layer includes a first material and a second material and an absolute value of a LUMO energy level of the first material is different from an absolute value of a LUMO energy level of the second material.

4. The organic light emitting display device of claim 3 , wherein the absolute value of a LUMO energy level of the first material is within a range of 2.91 eV to 3.40 eV and the absolute value of a LUMO energy level of the second material is within a range of 2.60 eV to 2.90 eV.

5. The organic light emitting display device of claim 3 , wherein an amount of the second material is higher than an amount of the first material.

6. The organic light emitting display device of claim 3 , wherein a content of the second material is more than 50 wt % of a content of the first material.

7. The organic light emitting display device of claim 3 , wherein the first material comprises one among anthracene derivatives, triazine derivatives, and carbozole derivatives.

8. The organic light emitting display device of claim 1 , wherein the first hole transfer layer includes a P-type hole transfer layer doped with a P-type dopant.

9. The organic light emitting display device of claim 1 , wherein the first emission layer and the second emission layer include one or more of a red emitting layer, a green emitting layer, and a blue emitting layer.

10. The organic light emitting display device of claim 1 , wherein the first emission layer and the second emission layer emit light having a same color.

11. The organic light emitting display device of claim 1 , further comprising a P-type charge generation layer between the N-type charge generation layer and the second hole transfer layer.

12. The organic light emitting display device of claim 1 , further comprising an emission control layer between the second hole transfer layer and the second emission layer and an absolute value of a highest occupied molecular orbital (HOMO) energy level of the emission control layer is greater than an absolute value of a HOMO energy level of the second hole transfer layer.

13. The organic light emitting display device of claim 12 , wherein a hole mobility of the emission control layer is lower than a hole mobility of the second hole transfer layer.

14. The organic light emitting display device of claim 1 , further comprising an emission control layer between the first hole transfer layer and the first emission layer, and an absolute value of a highest occupied molecular orbital (HOMO) energy level of the emission control layer is greater than an absolute value of a HOMO energy level of the first hole transfer layer.

15. The organic light emitting display device of claim 14 , wherein a hole mobility of the emission control layer is lower than a hole mobility of the first hole transfer layer.

16. The organic light emitting display device of claim 1 , further comprising a first emission control layer between the first hole transfer layer and the first emission layer, and a second emission control layer between the second hole transfer layer and the second emission layer.

17. The organic light emitting display device of claim 16 , wherein an absolute value of a highest occupied molecular orbital (HOMO) energy level of the first emission control layer is greater than an absolute value of a HOMO energy level of the first hole transfer layer and an absolute value of a highest occupied molecular orbital (HOMO) energy level of the second emission control layer is greater than an absolute value of a HOMO energy level of the second hole transfer layer.

18. The organic light emitting display device of claim 16 , wherein a hole mobility of the first emission control layer is lower than a hole mobility of the first hole transfer layer and a hole mobility of the second emission control layer is lower than a hole mobility of the second hole transfer layer.

19. An organic light emitting display device, comprising:
a plurality of pixels on a substrate, the plurality of pixels having a red subpixel, a green subpixel, and a blue subpixel;
an anode on the substrate;
a first hole transfer layer on the anode;
a first emission layer on the first hole transfer layer in the red subpixel, the green subpixel, and the blue subpixel;
a first electron transfer layer on the first emission layer;
an N-type charge generation layer on the first electron transfer layer;
a second hole transfer layer on the N-type charge generation layer;
a second emission layer on the second hole transfer layer in the red subpixel, the green subpixel, and the blue subpixel;
a second electron transfer layer on the second emission layer, the second electron transfer layer having a first material and a second material, and an absolute value of a lowest unoccupied molecular orbital (LUMO) energy level of the first material being larger than an absolute value of a LUMO energy level of the second material; and
a cathode on the second electron transfer layer,
wherein a difference between a lowest unoccupied molecular orbital (LUMO) energy level of the first electron transfer layer and a LUMO energy level of the N-type charge generation layer is 0.50 eV to 1.00 eV.

20. The organic light emitting display device of claim 19 , wherein the first material has an absolute value of the LUMO energy level is within a first range of 2.91 eV to 3.40 eV and the second material has an absolute value of the LUMO energy level is within a second range of 2.60 eV to 2.90 eV.

21. The organic light emitting display device of claim 19 , wherein an amount of the second material is higher than an amount of the first material.

22. The organic light emitting display device of claim 19 , wherein in the second electron transfer layer, a content of the second material is more than 50 wt %.

23. The organic light emitting display device of claim 19 , further comprising an emission control layer between the second hole transfer layer and the second emission layer, and an absolute value of a highest occupied molecular orbital (HOMO) energy level of the em

Assignees

• Lg Display Co Ltd

Inventors

• Park Eunjung

Classifications

• H10K71/16

  using physical vapour deposition [PVD], e.g. vacuum deposition or sputtering · CPC title

• H10K50/125

  specially adapted for multicolour light emission, e.g. for emitting white light · CPC title

• H10K59/10

  OLED displays · CPC title

• H10K50/11

  characterised by the electroluminescent [EL] layers · CPC title

• H10K2101/30

  Highest occupied molecular orbital [HOMO], lowest unoccupied molecular orbital [LUMO] or Fermi energy values · CPC title