Dual panel type organic electroluminescent display device and method of fabricating the same

1. An organic electroluminescent device, comprising:

a switching element and a driving element connected to the switching element on a substrate including a pixel region;

a first passivation layer including a contact hole on the driving element;

a cathode on the first passivation layer and connected to the driving element through the contact hole;

a first buffer layer on the cathode;

a second passivation layer on the first buffer layer, the second passivation layer and the first buffer layer having a contact hole that exposes a portion of the cathode;

an emitting layer on the cathode; and

an anode on the emitting layer,

wherein the first buffer layer includes molybdenum (Mo).

2. The device according to claim 1 , wherein the anode includes one of indium tin oxide (ITO) and indium zinc oxide (IZO).

3. The device according to claim 1 , further comprising:

an electron injection layer on the cathode;

an electron transport layer on the electron injection layer;

a hole transport layer on the emitting layer;

a hole injection layer on the hole transport layer; and

a second buffer layer on the hole injection layer.

4. The device according to claim 3 , wherein the second buffer layer includes a material selected from one of an organic insulating material and an oxide, and

wherein the organic insulating material has a crystallinity and the oxide includes vanadium pentoxide (V 2 O 5 ).

5. The device according to claim 4 , wherein the organic insulating material includes copper phthalocyanine (CuPc).

6. The device according to claim 1 , wherein the driving element is a negative type thin film transistor including a first gate electrode, a first semiconductor layer corresponding to the first gate electrode, a first source electrode, and a first drain electrode spaced apart from the first source electrode, and

wherein the first source and first drain electrodes are connected to end portions of the first semiconductor layer.

7. The device according to claim 6 , wherein the first drain electrode is connected to the cathode.

8. The device according to claim 6 , wherein the first source electrode has a “U” shape and the first drain electrode has a bar shape, and

wherein the first drain electrode is disposed in and spaced apart from the first source electrode.

9. The device according to claim 6 , wherein the first source electrode has a ring shape and the first drain electrode has a circular shape, and

wherein the first drain electrode is disposed in and spaced apart from the first source electrode.

10. The device according to claim 6 , further comprising:

gate and data lines connected to the switching element and crossing each other to define the pixel region; and

a power line crossing one of the gate line and the data line.

11. The device according to claim 10 , wherein the gate line, the data line and the power line include a gate pad, a data pad and a power pad at end portions thereof, respectively.

12. The device according to claim 10 , wherein the switching element is a thin film transistor including a second gate electrode connected to the gate line, a second semiconductor layer corresponding to the second gate electrode, a second source electrode connected to the data line, and a second drain electrode spaced apart from each other, and

wherein the second source and second drain electrodes are connected to end portions of the second semiconductor layer.

13. The device according to claim 12 , further comprising:

a storage capacitor including a first storage electrode connected to the power line, a second storage electrode connected to the second drain electrode, and an insulating layer between the first and second storage electrodes.

14. A method of fabricating an organic electroluminescent device, comprising:

forming a switching element and a driving element connected to the switching element on a substrate including a pixel region;

forming a first passivation layer including a contact hole on the driving element;

forming a cathode on the first passivation layer, the cathode connected to the driving element through the contact hole;

forming a first buffer layer on the cathode;

forming a second passivation layer on the first buffer layer;

forming a contact hole that exposes a portion of the cathode in the first buffer layer and the second passivation layer by simultaneously patterning the first buffer layer and the second passivation layer;

forming an emitting layer on the cathode; and

forming an anode on the emitting layer wherein the first buffer layer includes molybdenum (Mo).

15. The method according to claim 14 , wherein the anode includes one of indium tin oxide (ITO) and indium zinc oxide (IZO).

16. The method according to claim 14 , further comprising:

forming an electron injection layer on the cathode;

forming an electron transport layer on the electron injection layer;

forming a hole transport layer on the emitting layer;

forming a hole injection layer on the hole transport layer; and

forming a second buffer layer on the hole injection layer.

17. The method according to claim 16 , wherein the second buffer layer includes a material selected from one of an organic insulating material and an oxide, and

wherein the organic insulating material has a crystallinity and the oxide includes vanadium pentoxide (V 2 O 5 ).

18. The method according to claim 17 , wherein the organic monomolecular material includes copper phthalocyanine (CuPc).

19. The method according to claim 14 , wherein the driving element is a negative type thin film transistor including a first gate electrode, a first semiconductor layer corresponding to the first gate electrode, a first source electrode, and a first drain electrode spaced apart from the first source electrode, and

wherein the first source and first drain electrodes are connected to end portions of the first semiconductor layer.

20. The method according to claim 19 , further comprising:

connecting the first drain electrode to the cathode.

21. The method according to claim 19 , wherein the first source electrode has a “U” shape and the first drain electrode has a bar shape, and

wherein the first drain electrode is disposed in and spaced apart from the first source electrode.

22. The method according to claim 19 , wherein the first source electrode has a ring shape and the first drain electrode has a circular shape, and

wherein the first drain electrode is disposed in and spaced apart from the first source electrode.

23. The method according to claim 19 , further comprising:

forming gate and data lines connected to the switching element and crossing each other to define the pixel region; and

forming a power line crossing one of the gate line and the data line.

24. The method according to claim 23 , further comprising:

forming a gate pad, a data pad and a power pad at end portions of the gate line, the data line and the power line include, respectively.

25. The method according to claim 23 , wherein the switching element includes a second gate electrode connected to the gate line, a second semiconductor layer corresponding to the second gate electrode, a second source electrode connected to the data line, and a second drain electrode spaced apart from each other, and

wherein the second source and second drain electrodes are connected to end portions of the second semiconductor layer.

26. The method according to claim 25 , further comprising:

forming a storage capacitor including:

forming a first storage electrode connected to the power line;

forming a second storage electrode connected to the second drain electrode; and

forming an insulating layer between the first and second storage electrodes.