Organic light-emitting device having enhanced light extraction efficiency

1. An enhanced light extraction OLED device comprising:

(a) a transparent substrate;

(b) a light scattering layer disposed over a first surface of the transparent substrate;

(c) a transparent first electrode layer disposed over the light scattering layer;

(d) an organic EL element disposed over the transparent first electrode layer and including one or more organic layers but at least one light emitting layer in which light is produced;

(e) a transparent second electrode layer disposed over the organic EL element;

(f) a reflector layer disposed over the transparent second electrode layer; and

(g) a low index isolation layer having an optical index lower than the light emitting layer disposed between the transparent second electrode layer and the reflector layer.

2. The OLED device of claim 1 wherein the isolation layer is a photo-polymer.

3. The OLED device of claim 1 wherein the isolation layer is an inorganic dielectric layer including MgF 2 , NaF, KF, Bi 2 S 3 , or Na 5 Al 3 F 14 .

4. The OLED device of claim 1 wherein the reflector layer is selected from the group consisting of Ag, Ag-based alloys, and Al.

5. The OLED device of claim 1 wherein the reflector layer is selected from the group consisting of Ag and Ag-based alloys with more than 90% Ag.

6. The OLED device of claim 1 further including a light reflective structure spaced from the OLED device which reflects light in the direction of the OLED device.

7. The OLED device of claim 1 wherein the transparent substrate is a flexible sheet.

8. The OLED device of claim 7 wherein the OLED device is enclosed in a hermetically sealed enclosure having a transparent window through which light produced by the OLED device passes.

9. The OLED device of claim 8 wherein the sealed enclosure is in the shape of an incandescent light bulb.

10. An enhanced light extraction OLED) device comprising:

(a) a transparent substrate;

(b) a transparent first electrode layer disposed over a first surface of the transparent substrate;

(c) an organic EL element disposed over the first electrode layer and including one or more organic layers but at least one emissive layer in which light is produced;

(d) a transparent second electrode layer disposed over the organic EL element, and

(e) a light scattering layer disposed over the transparent second electrode layer.

11. The OLED device of claim 10 wherein a reflector layer is disposed over the light scattering layer.

12. The OLED device of claim 11 wherein a low index isolation layer having an optical index lower than the light emitting layer is disposed between the light scattering layer and the reflector layer.

13. The OLED device of claim 10 wherein the light scattering layer includes light scattering particles dispersed in a matrix.

14. The OLED device of claim 10 wherein the matrix has optical index no less than 0.9 times the optical index of the light emitting layer.

15. The OLED device of claim 10 wherein the light scattering particles have optical index different from the matrix.

16. The OLED device of claim 12 wherein the isolation layer is a photo-polymer.

17. The OLED device of claim 12 wherein the isolation layer is an inorganic dielectric layer including MgF 2 , NaF, KF, Bi 2 S 3 , or Na 5 Al 3 F 14 .

18. The OLED device of claim 11 wherein the reflector layer is selected from the group consisting of Ag, Ag-based alloys, and Al.

19. The OLED device of claim 11 wherein the reflector layer is selected from the group consisting of Ag and Ag-based alloys with more than 90% Ag.

20. An enhanced light extraction OLED device comprising:

(a) a substrate;

(b) a reflector layer disposed over a first surface of the substrate;

(c) a light scattering layer;

(d) a transparent first electrode layer disposed over the light scattering layer;

(e) an organic EL element disposed over the transparent first electrode layer and including one or more organic layers but at least one emissive layer in which light is produced; and

(f) a transparent second electrode layer disposed over the organic EL element.

21. The OLED device of claim 20 wherein a low index isolation layer is disposed between the reflector layer and the light scattering layer.

22. The OLED device of claim 20 wherein the light scattering layer includes light scattering particles dispersed in a matrix.

23. The OLED device of claim 22 wherein the matrix has optical index no less than 0.9 times the optical index of the light emitting layer.

24. The OLED device of claim 22 wherein the light scattering particles have optical index different from the matrix.

25. The OLED device of claim 21 wherein the isolation layer is a photo-polymer.

26. The OLED device of claim 21 wherein the isolation layer is an inorganic dielectric layer including MgF 2 , NaF, KF, Bi 2 S 3 , or Na 5 Al 3 F 14 .

27. The OLED device of claim 20 wherein the reflector layer is selected from the group consisting of Ag, Ag-based alloys, and Al.

28. The OLED device of claim 20 wherein the reflector layer is selected from the group consisting of Ag and Ag-based alloys with more than 90% Ag.

29. An enhanced light extraction OLED device comprising:

(a) a substrate;

(b) a reflector layer disposed over a first surface of the substrate;

(c) a transparent first electrode layer disposed over the reflector layer;

(d) an organic EL element disposed over the transparent first electrode layer and including one or more organic layers but at least one emissive layer in which light is produced;

(e) a transparent second electrode layer disposed over the organic EL element; and

(f) a light scattering layer disposed over the transparent second electrode layer; and

(g) a low index isolation layer is disposed between the reflector layer and the organic element.

30. The OLED device of claim 29 wherein the isolation layer is a photo-polymer.

31. The OLED device of claim 29 wherein the isolation layer is an inorganic dielectric layer including MgF 2 , NaF, KF, Bi 2 S 3 , or Na 5 Al 3 F 14 .

32. The OLED device of claim 29 wherein the reflector layer is selected from the group consisting of Ag, Ag-based alloys, and Al.

33. The OLED device of claim 29 wherein the reflector layer is selected from the group consisting of Ag and Ag-based alloys with more than 90% Ag.

34. An enhanced light extraction OLED device comprising:

(a) a transparent substrate;

(b) a light scattering layer disposed over a first surface of transparent substrate;

(c) a transparent first electrode layer disposed over the light scattering layer;

(d) an organic EL element disposed over the transparent first electrode layer and including one or more organic layers but at least one light emitting layer in which light is produced;

e) a reflecting second electrode layer disposed over the organic EL element, wherein material for the reflecting second electrode layer is selected from a list including Ag, Ag-based alloys, and Al;

f) an interlayer disposed between the organic EL element and the reflecting second electrode layer to improve device stability.

35. The OLED device of claim 34 wherein the reflecting second electrode is selected from the group consisting of Ag and Ag-based alloys with more than 90% Ag.

36. The OLED device of claim 34 wherein the interlayer is an inorganic transparent conductive layer.

37. The OLED device of claim 34 wherein the interlayer is selected from the group consisting of indium-tin oxide, indium-zinc oxide, zinc-tin oxide, and antimony oxide.

38. The OLED device of claim 34 wherein the interlayer is a metal containing phthalocyanine including copper phthalocyanine.

39. An enhanced light extraction OLED device comprising:

(a) a substrate;

(b) a reflecting first electrode layer disposed over the substrate, wherein the material for the reflecting first electrode layer is selected from a list including Ag, Ag-based alloys, and Al;

(c) an organic EL element disposed over the reflecting first electrode layer and including one or more organic layers but at least one light emitting layer in which light is produced;

(d) a transparent second electrode layer disposed over the organic EL element;

(e) a light scattering layer disposed over the transparent second electrode layer; and

(f) an interlayer disposed between the organic EL element and the reflecting first electrode layer to improve device stability wherein the interlayer is selected from the group consisting of indium-tin oxide, indium-zinc oxide, zinc-tin oxide, and antimony oxide.

40. The OLED device of claim 39 wherein the reflecting second electrode is selected from the group consisting of Ag and Ag-based alloys with more than 90% Ag.

41. The OLED device of claim 39 wherein the interlayer is an inorganic transparent conductive layer.

42. An enhanced light extraction OLED device comprising:

(a) a transparent substrate;

(b) a light scattering layer disposed over a first surface of the transparent substrate wherein the light scattering layer comprises light scattering particles dispersed in a matrix and the matrix has an optical index no less than 0.9 times the optical index of the light emitting layer;

(c) a transparent first electrode layer disposed over the light scattering layer,

(d) an organic EL element disposed over the transparent first electrode layer and including one or more organic layers but at least one light emitting layer in which light is produced; and

(e) a transparent second electrode layer disposed over the organic EL element.

43. The OLED device of claim 42 wherein the light scattering particles have optical index different from the matrix.

44. An enhanced light extraction OLED device comprising:

(a) a substrate;

(b) a reflecting first electrode layer disposed over the substrate, wherein the material for the reflecting first electrode layer is selected from a list including Ag, Ag-based alloys, and Al;

(c) an organic EL element disposed over the reflecting first electrode layer and including one or more organic layers but at least one light emitting layer in which light is produced;

(d) a transparent second electrode layer disposed over the organic EL element;

(e) a light scattering layer disposed over the transparent second electrode layer; and

(f) an interlayer disposed between the organic EL element and the reflecting first electrode layer to improve device stability wherein the interlayer is a metal containing phthalocyanine including copper phthalocyanine.

45. An enhanced light extraction OLED device comprising:

(a) a substrate;

(b) a reflector layer disposed over a first surface of the substrate;

(c) a transparent first electrode layer disposed over the reflector layer;

(d) an organic EL element disposed over the transparent first electrode layer and including one or more organic layers but at least one emissive layer in which light is produced;

(e) a transparent second electrode layer disposed over the organic EL element; and

(f) a light scattering layer disposed over the transparent second electrode layer wherein the light scattering layer includes a matrix having dispersed light scattering particles, the matrix having an optical index no less than 0.9 times the optical index of the light emitting layer.