Organic light emitting display device

1. An organic light emitting display device comprising:

a substrate;

a first electrode layer formed on the substrate;

an emission structure layer formed on the first electrode layer;

an electron injection layer (EIL) formed on and contacting the emission structure layer and comprising a composite layer of LiF:Yb; and

a second electrode layer formed on the EIL.

2. The organic light emitting display device of claim 1 , wherein the composition ratio of LiF:Yb is from about 3:7 to about 7:3.

3. The organic light emitting display device of claim 1 , wherein a thickness of the EIL is from about 50 Å to about 100 Å.

4. The organic light emitting display device of claim 1 , wherein the emission structure layer comprises a hole injection and transport layer (HITL), and an emission layer (EML) formed on the HITL.

5. The organic light emitting display device of claim 1 , wherein the emission structure layer comprises a hole injection layer (HIL), a hole transport layer (HTL) formed on the HIL, and an EML formed on the HTL.

6. The organic light emitting display device of claim 4 , further comprising an optical correction layer formed between the HITL and the EML.

7. The organic light emitting display device of claim 5 , further comprising an optical correction layer formed between the HTL and the EML.

8. The organic light emitting display device of claim 6 , wherein the optical correction layer is an HTL.

9. The organic light emitting display device of claim 4 , wherein the EML has an electron mobility equal to or greater than about 1.4×10 −6 cm 2 /V·s.

10. The organic light emitting display device of claim 1 , wherein the first electrode layer is an anode and the second electrode layer is a cathode.

11. The organic light emitting display device of claim 1 , wherein the first electrode layer is a cathode and the second electrode layer is an anode.

12. The organic light emitting display device of claim 10 or 11 , wherein the anode comprises a transparent conductive oxide.

13. The organic light emitting display device of claim 12 , wherein the anode comprises indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or In 2 O 3 .

14. The organic light emitting display device of claim 10 , wherein the cathode comprises an alloy containing silver (Ag).

15. The organic light emitting display device of claim 10 , wherein the cathode is an Ag monolayer.

16. The organic light emitting display device of claim 1 , wherein the first electrode layer is a common electrode layer of pixels.

17. The organic light emitting display device of claim 1 , wherein the second electrode layer is a common electrode layer of pixels.

18. An organic light emitting display device comprising:

a substrate;

a thin film transistor (TFT) comprising an active layer and a gate electrode formed on the substrate, a gate insulating layer formed between the active layer and the gate electrode, and source and drain electrodes contacting the active layer;

a first electrode layer contacting one of the source and drain electrodes of the TFT;

an emission structure layer formed on the first electrode layer;

an electron injection layer (EIL) formed on and contacting the emission structure layer and comprising a composite layer of LiF:Yb; and

a second electrode layer formed on the EIL.

19. The organic light emitting display device of claim 18 , wherein the composition ratio of LiF:Yb is from about 3:7 to about 7:3.

20. The organic light emitting display device of claim 18 , wherein a thickness of the EIL is from about 50 Å to about 100 Å.