Organic light emitting display device and organic light emitting stacked structure

1. An organic light emitting display device including an emission part which is disposed between an anode and a cathode and includes an emission layer, the emission part comprising:

at least two emission layers emitting lights of different colors, the at least two emission layers each including at least one host and at least one dopant; and

a recombination zone movement prevention layer on a specific emission layer among the at least two emission layers,

wherein

the specific emission layer comprises one among a yellow-green emission layer, a green emission layer, and a combination of a yellow-green emission layer and a green emission layer, and

the recombination zone movement prevention layer comprises a host which is the same as a host in the yellow-green emission layer or the green emission layer.

2. The organic light emitting display device of claim 1 , wherein the at least two emission layers comprise one among a combination of a red emission layer and a yellow-green emission layer, a combination of a red emission layer and a green emission layer, and a combination of a red emission layer, a yellow-green emission layer, and a green emission layer.

3. The organic light emitting display device of claim 2 , wherein the red emission layer is disposed closer to the anode than the yellow-green emission layer or the green emission layer.

4. The organic light emitting display device of claim 2 , wherein

one among the yellow-green emission layer, the green emission layer, and the combination of the yellow-green emission layer and the green emission layer comprises at least two zones which differ in content of the dopant, and

the content of the dopant decreases progressively closer to the cathode.

5. The organic light emitting display device of claim 2 , wherein a ratio of a thickness of the red emission layer to a thickness of the recombination zone movement prevention layer is 1:1 to 3:1.

6. The organic light emitting display device of claim 2 , wherein the red emission layer comprises a host, the host being a single host.

7. An organic light emitting display device including an emission part which is disposed between an anode and a cathode and includes an emission layer, the emission layer comprising:

a first emission layer; and

a second emission layer emitting light of a color which differs from a color of light emitted from the first emission layer,

wherein

the emission part comprises a recombination zone movement prevention layer on the second emission layer, and

when a thickness of the first emission layer is A, a thickness of the second emission layer is B, and a thickness of the recombination zone movement prevention layer is C, B>A≧C is satisfied,

wherein the first emission layer comprises a red emission layer, and the second emission layer comprises one among a yellow-green emission layer, a green emission layer, and a combination of a yellow-green emission layer and a green emission layer, and

wherein the second emission layer is provided between the first emission layer and the recombination zone movement prevention layer.

8. The organic light emitting display device of claim 7 , wherein the thickness of the first emission layer is within a range of one times to three times the thickness of the recombination zone movement prevention layer.

9. The organic light emitting display device of claim 7 , wherein

the first emission layer comprises a single host, and

the second emission layer comprises a mixed host.

10. The organic light emitting display device of claim 9 , wherein

the second emission layer further comprises at least one dopant and comprises at least two zones which differ in content of the dopant, and

the content of the dopant decreases progressively closer to the cathode.

11. The organic light emitting display device of claim 7 , wherein the recombination zone movement prevention layer comprises a material which is the same as a host included in the second emission layer.

12. The organic light emitting display device of claim 7 , wherein the first emission layer is disposed closer to the anode than the second emission layer.

13. An organic light emitting stacked structure comprising:

a first emission layer including a single host and at least one dopant;

a second emission layer on the first emission layer, the second emission layer emitting light of a color, which differs from a color of light emitted from the first emission layer, and including at least one host and at least one dopant;

a function layer on the second emission layer, the function layer preventing efficiency of the second emission layer from being reduced due to an increase in thickness of the first emission layer, and

a cathode on the function layer,

wherein the second emission layer comprises one among a yellow-green emission layer, a green emission layer, and a combination of a yellow-green emission layer and a green emission layer, and

wherein one among the yellow-green emission layer, the green emission layer, and the combination of the yellow-green emission layer and the green emission layer comprises at least two zones which differ in content of the dopant, and the content of the dopant decreases progressively closer to the cathode.

14. The organic light emitting stacked structure of claim 13 , wherein the function layer has hole-blocking characteristic for preventing moving of a hole of the second emission layer.

15. The organic light emitting stacked structure of claim 13 , wherein the function layer comprises a material which is the same as a host in the second emission layer.

16. The organic light emitting stacked structure of claim 13 , wherein a thickness of the second emission layer is within four times a thickness of the first emission layer.

17. The organic light emitting stacked structure of claim 13 , wherein a thickness of the first emission layer is equal to or greater than a thickness of the function layer.

18. The organic light emitting stacked structure of claim 13 , wherein

the first emission layer comprises a red emission layer.