Organic electro luminescence device and display device including the same

1. An organic electroluminescence device comprising:

a first electrode;

a hole transport region disposed on the first electrode;

an emission layer disposed on the hole transport region;

an electron transport region disposed on the emission layer; and

a second electrode disposed on the electron transport region,

wherein the hole transport region includes:

a first hole transport layer disposed adjacent to the first electrode, the first hole transport layer including a first organic compound having a first dielectric constant; and

a second hole transport layer disposed between the first hole transport layer and the emission layer, the second hole transport layer including a second organic compound having a second dielectric constant which is greater than the first dielectric constant, wherein

a ratio of a thickness of the first hole transport layer to a thickness of the second hole transport layer is in a range of about 1:1 to about 1:12.

2. The organic electroluminescence device of claim 1 , wherein a ratio of the first dielectric constant to the second dielectric constant is in a range of about 1:1.20 to about 1:2.25.

3. The organic electroluminescence device of claim 1 , wherein a difference between the first dielectric constant and the second dielectric constant is in a range of about 0.6 to about 2.5.

4. The organic electroluminescence device of claim 1 , wherein

the first dielectric constant is in a range of about 2.0 to about 2.8, and

the second dielectric constant is in a range of about 3.4 to about 4.5.

5. The organic electroluminescence device of claim 1 , wherein

a thickness of the first hole transport layer is in a range of about 10 nm to about 60 nm, and

a thickness of the second hole transport layer is in a range of about 60 nm to about 120 nm.

6. The organic electroluminescence device of claim 1 , wherein the hole transport region further comprises a third hole transport layer disposed between the second hole transport layer and the emission layer, the third hole transport layer including the first organic compound.

7. The organic electroluminescence device of claim 6 , wherein a ratio of a thickness of the first hole transport layer to a thickness of the second hole transport layer to a thickness of the third hole transport layer is in a range of about 1:2:1 to about 1:11:1.

8. The organic electroluminescence device of claim 6 , wherein

a thickness of the first hole transport layer is in a range of about 10 nm to about 30 nm,

a thickness of the second hole transport layer is in a range of about 60 nm to about 110 nm, and

a thickness of the third hole transport layer is in a range of about 10 nm to about 30 nm.

9. The organic electroluminescence device of claim 6 , wherein the hole transport region further comprises:

a fourth hole transport layer disposed between the third hole transport layer and the emission layer, the fourth hole transport layer including the second organic compound; and

a fifth hole transport layer disposed between the fourth hole transport layer and the emission layer, the fifth hole transport layer including the first organic compound.

10. The organic electroluminescence device of claim 9 , wherein

a ratio of a thickness of the first hole transport layer to a thickness of the second hole transport layer is in a range of about 1:0.5 to about 1:3,

a ratio of a thickness of the first hole transport layer to a thickness of the third hole transport layer is in a range of about 1:1 to about 1:5,

a ratio of a thickness of the first hole transport layer to a thickness of the fourth hole transport layer is in a range of about 1:0.5 to about 1:3, and

a ratio of a thickness of the first hole transport layer to a thickness of the fifth hole transport layer is in a range of about 1:0.5 to about 1:2.

11. The organic electroluminescence device of claim 9 , wherein

a thickness of the first hole transport layer and a thickness of the fifth hole transport layer are each in a range of about 10 nm to about 20 nm,

a thickness of the second hole transport layer and a thickness of the fourth hole transport layer are each in a range of about 10 nm to about 30 nm, and

a thickness of the third hole transport layer is in a range of about 20 nm to about 50 nm.

12. The organic electroluminescence device of claim 6 , further comprising:

a sixth hole transport layer disposed between the first hole transport layer and the second hole transport layer, the sixth hole transport layer including the first organic compound and the second organic compound; and

a seventh hole transport layer disposed between the second hole transport layer and the third hole transport layer, the seventh hole transport layer including the first organic compound and the second organic compound.

13. The organic electroluminescence device of claim 12 , wherein a volume ratio of the first organic compound to the second organic compound included in the sixth hole transport layer and the seventh hole transport layer is in a range of about 2:8 to about 8:2.

14. The organic electroluminescence device of claim 12 , wherein a dielectric constant of the sixth hole transport layer and a dielectric constant of the seventh hole transport layer are each in a range of about 2.3 to about 3.3.

15. The organic electroluminescence device of claim 12 , wherein

a thickness of the first hole transport layer and a thickness of the third transport layer are each in a range of about 10 nm to about 20 nm,

a thickness of the second hole transport layer is in a range of about 20 nm to about 50 nm, and

a thickness of the sixth hole transport layer and a thickness of the seventh hole transport layer are each in a range of about 10 nm to about 30 nm.

16. The organic electroluminescence device of claim 1 , wherein

the first electrode is a reflective electrode, and

the second electrode is either a transflective or transmissive electrode.

17. The organic electroluminescence device of claim 1 , wherein the first organic compound is represented by Formula 1:

wherein, in Formula 1,

X is N, NR 1 , or CR 2 R 3 ,

m to o are each independently 0 or 1,

p is an integer of 0 to 4,

L 1 to L 3 are each independently a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms,

R 1 to R 3 are each independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, and

Ra to Rc are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted amine group,

wherein in case that X is N or NR 1 , at least one of Ra and Rb is a substituted or unsubstituted cyclohexyl group, a substituted or unsubstituted triphenylsilyl group, a fluorenyl group containing a substituted or unsubstituted alkyl group having 2 to 16 carbon atoms as a substituent, or an aryl group having 6 to 30 ring-forming carbon atoms containing a substituted or unsubstituted cyclohexyl group as a substituent, and

wherein in case that X is CR 2 R 3 ,

R 2 and R 3 are each independently a substituted or unsubstituted alkyl group having 6 to 10 carbon atoms, or

at least one of Ra and Rb is a substituted or unsubstituted cyclohexyl group, a substituted or unsubstituted triphenylsilyl group, a fluorenyl group containing a substituted or unsubstituted alkyl group having 2 to 16 carbon atoms as a substituent, or an aryl group having 6 to 30 ring-forming carbon atoms containing a substituted or unsubstituted cyclohexyl group as a substituent.

18. The organic electroluminescence device of claim 17 , wherein Formula 1 is represented by one of Formula 2 to Formula 4:

wherein m to p, Ra to Rc, L 1 to L 3 in Formula 2 to Formula 4, R 1 in Formula 3, and R 2 and R 3 in Formula 4 are the same as defined in Formula 1.

19. The organic electroluminescence device of claim 18 , wherein Formula 4 is represented by Formula 4-1:

wherein Ra to Rc, L 1 to L 3 , and m to p in Formula 4-1 are the same as defined in Formula 1.

20. The organic electroluminescence device of claim 17 , wherein Formula 1 is represented by Formula 5:

wherein m to p, Ra to Rc, and X in Formula 5 are the same as defined in Formula 1.

21. The organic electroluminescence device of claim 17 , wherein in Formula 1, Ra and Rb are each independently represented by one of Formula 6 to Formula 13 below:

22. The organic electroluminescence device of claim 17 , wherein the first organic compound is represented by one of compounds of Compound group 1:

23. A display device comprising

a plurality of organic electroluminescence devices, wherein

each of the plurality of organic electroluminescence devices includes:

a first electrode;

a hole transport region disposed on the first electrode;

an emission layer disposed on the hole transport region;

an electron transport region disposed on the emission layer; and

a second electrode disposed on the electron transport region,

wherein the hole transport region includes:

a first hole transport layer disposed adjacent to the first electrode, the first hole transport layer including a first organic compound having a first dielectric constant; and

a second hole transport layer disposed between the first hole transport layer and the emission layer, the second hole transport layer including a second organic compound having a second dielectric constant which is greater than the first dielectric constant, and

wherein the plurality of organic electroluminescence devices comprise:

a first organic electroluminescence device including a first emission layer that emits light of a first wavelength;

a second organic electroluminescence device including a second emission layer that emits light of a second wavelength which is different from the first wavelength; and

a third organic electroluminescence device including a third emission layer that emits light of a third wavelength which is different from the first wavelength and the second wavelength.

24. The display device of claim 23 , wherein

the first dielectric constant is in a range of about 2.0 to about 2.8, and

the second dielectric constant is in a range of about 3.4 to about 4.5.

25. The display device of claim 23 , wherein

the first electrode is a reflective electrode, and

the second electrode is either a transmissive electrode or a transflective electrode.

26. The display device of claim 23 , wherein

the first wavelength is a wavelength longer than the second wavelength,

the second wavelength is a wavelength longer than the third wavelength,

a thickness of the first emission layer is greater than a thickness of the second emission layer, and

a thickness of the second emission layer is greater than the thickness of the third emission layer.

27. The display device of claim 23 , wherein

the first wavelength is a wavelength longer than the second wavelength,

the second wavelength is a wavelength longer than the third wavelength,

the display device further comprises:

a first resonance auxiliary layer disposed between the first emission layer and the hole transport region;

a second resonance auxiliary layer disposed between the second emission layer and the hole transport region; and

a third resonance auxiliary layer disposed between the third emission layer and the hole transport region,

a thickness of the first resonance auxiliary layer is greater than a thickness of the second resonance auxiliary layer, and

a thickness of the second resonance auxiliary layer is greater than a thickness of the third resonance auxiliary layer.