Sealed electrochromic device

• US 5,136,419 A
• Filed: 12/13/1991
• Issued: 08/04/1992
• Est. Priority Date: 03/06/1990
• Status: Expired due to Fees

• Current Assignee: The Dow Chemical Company (Dow, Inc.)
• Original Assignee: The Dow Chemical Company (Dow, Inc.)
• Inventors: Shabrang, Mani
• Primary Examiner(s): Jackson, Jr., Jerome
• Assistant Examiner(s): LIMANEK, ROBERT P
• Application Number:
  US07/809,209
• Time in Patent Office: 235 Days
• Field of Search: 350/357
• US Class Current: 359/265
• CPC Class Codes: G02F 1/161 Gaskets; Spacers; Sealing of cells; Filling or closing of cells

Abstract

An improved electrochromic device of the type employing: a working electrode, such as a thin essentially transparent layer of indium/tin oxide coated on glass; the working electrode being coated with an electrochromic layer, such as a thin essentially transparent layer of tungsten oxide; the electrochromic layer being coated with an ion conducting layer, such as a thin essentially transparent layer of a perfluorosulfonate polymer; the ion conducting layer being coated with a counter electrode, such as a thin essentially transparent layer of a layer of gold. The improvement is to operate such a device in an environment of a mixture of an inert gas and the vapor of a high dielectric constant material. This can be done in a sealed double pane window by forming such a device on one of the interior surfaces of the window panes and then filling the remaining space between the panes with a mixture of nitrogen and water vapor.

Claims

1. In an improved electrochromic device comprising a plurality of layers on one side of a backing, the layers generally comprising an electronically conducting layer, an electrochromic layer, an ion conducting layer and a counter electrode layer, wherein the improvement comprises:

(a) a panel, the panel juxtaposed substantially biplanar and spaced away from the one side of the backing and the layers thereon leaving a space volume between the panel and the layers; and

(b) means for sealing the panel with the backing so that at least a portion of the space volume is sealed between the panel and the backing to form a sealed space volume;

(c) a mixture of an inert gas and the vapor of a high dielectric constant material positioned in the sealed space volume, the mixture having an oxygen content of less than 10 percent.

2. The device of claim 1, wherein the high dielectric constant material has a dielectric constant of greater than about 25.

3. The device of claim 2, wherein the high dielectric constant material has a dielectric constant of greater than about 50.

4. The device of claim 3, wherein the high dielectric constant material has a dielectric constant of greater than about 70.

5. The device of claim 4, wherein the high dielectric constant material is water.

6. The device of claim 5, wherein the backing and the panel each are about the same size and wherein the means for sealing is located at the peripheral edges of the backing and the panel.

7. The device of claim 6, wherein the backing and the panel comprise panes of glass.

8. The device of claim 7, wherein the ion conducting layer comprises a polymeric electrolyte.

9. The device of claim 8, wherein the electronically conducting layer comprises indium/tin oxide, the electrochromic layer comprises tungsten oxide, the ion conducting layer comprises a perfluorosulfonic acid polymer and the counter electrode layer comprises gold.

23. The device of claim 5, wherein the relative humidity of the inert gas is higher than five percent.

24. The device of claim 5, wherein the relative humidity of the inert gas is higher than ten percent.

25. The device of claim 5, wherein the relative humidity of the inert gas is higher than twenty percent.

26. The device of claim 5, wherein the relative humidity of the inert gas is higher than twenty percent and lower than fifty percent.

36. The device of claim 23, wherein the relative humidity of the inert gas is higher than ten percent.

37. The device of claim 24, wherein the relative humidity of the inert gas is higher than twenty percent.

38. The device of claim 25, wherein the relative humidity of the inert gas is higher than twenty percent and lower than fifty percent.

39. The device of claim 9, wherein the ion conducting layer consists essentially of a polymer having a substantially fluorinated backbone which has recurring pendant groups attached thereto represented by the formula --O--(CFR'"'"'_f)_b --(DFR_f)_a --SO₃ --, where a=0-3, b=0-3, a+b=at least 1 , and R_f and R'"'"'_f are independently selected from the group consisting of a halogen and a substantially fluorinated alkyl group having one of more carbon atoms.

40. The device of claim 39, wherein the formula comprises --O--(CFR'"'"'_f)_b --(CFR_f)_a --SO₃ --H⁺, where a=0-3, b=0-3, a+b=at least 1, R_f and R'"'"'_f are independently selected from the group consisting of a halogen and a substantially fluorinated alkyl group having one or more carbon atoms.

41. The device of claim 40, wherein the ion conducting layer comprises a copolymer of FFC=CFF and FRC=CFF, where R is --O--CFF--CFF--SOOO--H⁺.

42. The device of claim 41, wherein the inert gas consists essentially of nitrogen.

10. In an improved sealed double pane window generally comprising a first pane of glass peripherally sealed with a second juxtaposed spaced apart substantially biplanar pane of glass so that a space volume is sealed between the first pane of glass and the second pane of glass, the first pane of glass having a first side and a second side, the second side being exposed to the sealed space volume, wherein the improvement comprises:

a multi-layer electrochromic system coated on the second side of the first pane of glass, the electrochromic system comprising an electronically conducting layer, an electrochromic layer, an ion conducting layer and a counter electrode layer; and

(b) a mixture of an inert gas and the vapor of a high dielectric constant material positioned in the sealed space volume, the mixture having an oxygen content of less than 10 percent.

11. The window of claim 10, wherein the high dielectric constant material has a dielectric constant of greater than about 25.

12. The window of claim 11, wherein the high dielectric constant material has a dielectric constant of greater than about 50.

13. The device of claim 12, wherein the high dielectric constant material has a dielectric constant of greater than about 70.

14. The device of claim 13, wherein the high dielectric constant material is water.

15. The device of claim 14, wherein the ion conducting layer comprises a polymeric electrolyte.

16. The device of claim 15, wherein the second side of the first pane of glass is coated with indium/tin oxide to form an electronically conducting layer, the electrochromic layer consists essentially of tungsten oxide positioned on the indium/tin oxide, the ion conducting layer consists essentially of a perfluorosulfonate polymer positioned on the tungsten oxide and the counter electrode layer consists essentially of gold positioned on the perfluorosulfonate polymer.

27. The device of claim 14, wherein the relative humidity of the inert gas is higher than five percent.

28. The device of claim 14, wherein the relative humidity of the inert gas is higher than ten percent.

29. The device of claim 14, wherein the relative humidity of the inert gas is higher than twenty percent.

30. The device of claim 14, wherein the relative humidity of the inert gas is higher than twenty percent and lower than fifty percent.

43. The device of claim 16, wherein the ion conducting layer consists essentially of a polymer having a substantially fluorinated backbone which has recurring pendant groups attached thereto represented by the formula --O--(CFR'"'"'_f)_b --(CFR_f)_a --SO₃ --, where a=0-3, b=0-3, a+b=at least 1, and R_f and R'"'"'_f are independently selected from the group consisting of a halogen and a substantially fluorinated alkyl group having one or more carbon atoms.

44. The device claim 43, wherein the formula comprises --O--(CFR'"'"'_f)_b --(CFR_f)_a --SO₃ --H⁺, where a=0-3, b=0-3, a+b=at least 1, R_f and R'"'"'_f are independently selected from the group consisting of a halogen and a substantially fluorinated alkyl group having one or more carbon atoms.

45. The device of claim 44, wherein the ion conducting layer comprises a copolymer of FFC=CFF and FRC=CFF, where R is --O--CFF--CFF--SOOO--H⁺.

46. The device of claim 45, wherein the inert gas consist essentially of nitrogen.

17. In an improved sealed double pane window generally comprising a first pane of glass peripherally sealed with a juxtaposed spaced apart second substantially biplanar pane of glass so that a given space volume is sealed between the first pane of glass and the second pane of glass, wherein the improvement comprises:

(a) a multi-layer electrochromic system of a given solid volume, the electrochromic system positioned in the sealed space volume, the volume of the electrochromic system being less than the sealed space volume so that there is a remaining sealed space volume, the electrochromic system comprising an electronically conducting layer, an electrochromic layer, an ion conducting layer and a counter electrode layer; and

(b) a mixture of an inert gas and the vapor of a high dielectric constant material positioned in the remaining sealed space volume, the mixture having an oxygen content of less than 10 percent.

18. The window of claim 17, wherein the high dielectric constant material has a dielectric constant of greater than about 25.

19. The window of claim 18, wherein the high dielectric constant material has a dielectric constant of greater than about 50.

20. The device of claim 19, wherein the high dielectric constant material has a dielectric constant of greater than about 70.

21. The device of claim 20, wherein the high dielectric constant material is water.

31. The device of claim 21, wherein the relative humidity of the inert gas is higher than five percent.

32. The device of claim 21, wherein the relative humidity of the inert gas is higher than ten percent.

33. The device of claim 21, wherein the relative humidity of the inert gas is higher than twenty percent.

34. The device of claim 21, wherein the relative humidity of the inert gas is higher than twenty percent and lower than fifty percent.

47. The device of claim 21, wherein the ion conducting layer consists essentially of a polymer having a substantially fluorinated backbone which has recurring pendant groups attached thereto represented by the formula --O--(CFR'"'"'_f)_b --(CFR_f)_a --SO₃ --, where a=0-3, b=0-3, a+b=at least 1, and R_f and R'"'"'_f are independently selected from the group consisting of a halogen and a substantially fluorinated alkyl group having one or more carbon atoms, the counter electrode layer consists essentially of gold positioned on one side of the ion conducting layer, the electrochromic layer consists essentially of tungsten oxide positioned on the other side of the ion conducting layer and the electronically conducting layer consists essentially of gold positioned on the electrochromic layer.

48. The device of claim 47, wherein the formula comprises --O--(CFR'"'"'_f)_b --(CFR_f)_a --SO₃ --H⁺, where a=0-3, b=0-3, a+b=at least 1, R_f and R'"'"'_f are independently selected from the group consisting of a halogen and a substantially fluorinated alkyl group having one or more carbon atoms.

49. The device of claim 48, wherein the ion conducting layer comprises a copolymer of FFC=CFF and FRC=CFF, where R is --O--CFF--CFF--SOOO--H⁺.

50. The device of claim 49, wherein the inert gas consists essentially of nitrogen.

22. In an improved electrochromic device comprising an electronic conductor, and electrochromic material, an ion conducting layer, and a counter electrode, the improvement comprising:

positioning the electronic conductor, the ion conducting layer, the electrochromic material and the counter electrode in a space consisting essentially of a mixture of an inert gas and water vapor, the mixture having an oxygen content of less than 10 percent.

35. The device of claim 22, wherein the relative humidity of the inert gas is higher than five percent.