Organic light emitting display device having layer to control charge transfer

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 emission control layer is greater than an absolute value of a HOMO energy level of the second hole transfer layer.

24. The organic light emitting display device of claim 23 , wherein a hole mobility of the emission control layer is lower than a hole mobility of the second hole transfer layer.

25. The organic light emitting display device of claim 19 , 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.

26. The organic light emitting display device of claim 25 , wherein a hole mobility of the emission control layer is lower than a hole mobility of the first hole transfer layer.

27. The organic light emitting display device of claim 19 , 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.

28. The organic light emitting display device of claim 27 , 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.

29. The organic light emitting display device of claim 28 , 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.

30. The organic light emitting display device of claim 19 , 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.

31. The organic light emitting display device of claim 19 , wherein the first emission layer and the second emission layer emit light having a same color.