Variable-emittance electrochromic devices and methods of preparing the same

• US 9,207,515 B2
• Filed: 03/15/2013
• Issued: 12/08/2015
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Ashwin-Ushas Corporation, Inc.
• Original Assignee: Ashwin-Ushas Corporation, Inc.
• Inventors: Chandrasekhar, Prasanna
• Primary Examiner(s): Pham, Thomas K
• Assistant Examiner(s): BROOME, SHARRIEF I
• Application Number:
  US13/842,148
• Publication Number:
  US 20140268283A1
• Time in Patent Office: 998 Days
• Field of Search: 359265-275, 359/245, 359/247, 359/252, 359/253, 359/296, 252/586, 345/49, 345/105, 348/817, 250/517.1, 521/713
• US Class Current: 1/1
• CPC Class Codes: G02F 1/155 Electrodes
• CPC Class Codes: G02F 1/157 Structural association of cells with optical devices, e.g. reflectors or illuminating devices
• CPC Class Codes: G02F 2001/164 the electrolyte is made of polymers
• CPC Class Codes: G02F 2203/11 involving infrared radiation

Abstract

Variable-emittance, electrochromic devices utilizing IR-active conducting polymers and methods of preparing the same are disclosed.

Claims

1. A flexible, variable-emittance, electrochromic device comprising:

(a) a working electrode comprising;

(i) an IR-active, electrochromic conducting polymer layer;

(ii) an electrolyte permeable substrate layer; and

(iii) a conductive reflective layer disposed between the electrolyte permeable substrate layer and the conducting polymer layer; and

(b) an ionic liquid electrolyte in electrochemical communication with the conducting polymer layer;

the ionic liquid electrolyte comprising at least one counterion, wherein the ionic liquid electrolyte comprises 1-butyl-3-methyl imidazoliumtetrafluoroborate (BMIM-BF₄), 1-butyl-3-methyl imidazoliumtrifluoroacetate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methyl imidazoliumtetrafluoroborate (EMIM-BF₄), BMIM-bis(trifluoromethylsulfonyl)amide (BMIM-TF₂N), 1-(4-sulfobutyl)-3-methylimidazolium trifluoromethanesulfonate, or a combination thereof;

wherein the electrochromic conducting polymer layer incorporates the at least one counterion of the ionic liquid electrolyte in an amount effective to enable efficient electrochromic switching of the device at temperatures of about −

80°

C. to about 95°

C.

2. The electrochromic device of claim 1, comprising at least one counter electrode.

3. The electrochromic device of claim 2, wherein the at least one counter electrode comprises a second conducting polymer layer.

4. The electrochromic device of claim 3, wherein the at least one counter electrode comprises a conductive metallic layer.

5. The electrochromic device of claim 3, wherein the at least one counter electrode comprises a second conductive reflective layer.

6. The electrochromic device of claim 5, wherein the second conductive reflective layer is disposed between the electrolyte permeable substrate layer and the second conducting polymer layer.

7. The electrochromic device of claim 5, wherein the at least one counter electrode comprises a second electrolyte permeable substrate layer.

8. The electrochromic device of claim 7, wherein the second conductive reflective layer is disposed between the second conducting polymer layer and the second electrolyte permeable substrate layer.

9. The electrochromic device of claim 5, wherein the second conductive reflective layer comprises an IR reflecting material.

10. The electrochromic device of claim 9, wherein the IR reflecting material comprises a noble metal.

11. The electrochromic device of claim 10, wherein the IR reflecting material comprises gold (Au), platinum (Pt) or a combination thereof.

12. The electrochromic device of claim 5, wherein the second conductive reflective layer is porous, perforated or a combination thereof.

13. The electrochromic device of claim 7, wherein the second electrolyte permeable substrate layer is porous, perforated or a combination thereof.

14. The electrochromic device of claim 13, wherein the second electrolyte permeable substrate layer comprises a microporous membrane having a pore size from at least about 0.01 μ

m to at least about 5.0 μ

m.

15. The electrochromic device of claim 14, wherein the microporous membrane has a pore size from at least about 0.05 μ

m to at least about 2.0 μ

m.

16. The electrochromic device of claim 7, wherein the second electrolyte permeable substrate layer comprises poly(sulfone), poly(propylene), poly(ethylene terephthalate), poly(methyl methacrylate), poly(ethyl methacrylate), poly(tetrafluoroethylene) and other fluorinated poly(alkylenes), nylon, poly(vinylidene fluoride), acrylonitrile methyl acrylate copolymers, ethylene vinyl acetate, fluorinated ethylenepropylene resins, poly(carbonates), poly(butylenes), poly(vinyl chloride), poly(imides) or a combination thereof.

17. The electrochromic device of claim 7, wherein the second electrolyte permeable substrate comprises poly(ethylene terephthalate), poly(tetrafluroethylene), poly(carbonate), poly(sulfone), poly(vinylidene fluoride), or a combination thereof.

18. The electrochromic device of claim 7, wherein the second electrolyte permeable substrate comprises woven synthetic textile cloth, nonwoven synthetic textile cloth, woven natural textile cloth, nonwoven natural textile cloth, paper or a combination thereof.

19. The electrochromic device of claim 3, wherein the second conducting polymer layer comprises poly(aniline), poly(diphenyl amine), poly(4-amino biphenyl), poly(diphenylbenzidine), poly(3-alkyl thiophene) or a combination thereof.

20. The electrochromic device of claim 3, wherein the conducting polymer layer and the second conducting polymer layer are the same.

21. The electrochromic device of claim 3, wherein the second conducting polymer layer comprises at least one dopant.

22. The electrochromic device of claim 21, wherein the at least one dopant comprises poly(anetholesulfonate), poly(vinyl sulfate), p-toluene sulfonate, trifluoromethanesulfonate or a combination thereof.

23. The electrochromic device of claim 3, wherein the ionic liquid electrolyte is in electrochemical communication with the second conducting polymer layer, the ionic liquid electrolyte comprising at least one counterion;

and wherein the electrochromic conducting polymer layer substantially incorporates the at least one counterion of the ionic liquid electrolyte.

24. The electrochromic device of claim 1, wherein the at least one counterion is selected from the group consisting of trifluoroacetate, tetrafluoroborate (BF₄) and trifluoromethanesulfonate.

25. The electrochromic device of claim 1, wherein the conducting polymer layer comprises poly(aniline), poly(diphenyl amine), poly(4-amino biphenyl), poly(diphenylbenzidine), poly(3-alkyl thiophene) or a combination thereof.

26. The electrochromic device of claim 1, wherein the conducting polymer layer is poly(aniline).

27. The electrochromic device of claim 1, wherein the conducting polymer layer comprises at least one dopant.

28. The electrochromic device of claim 27, wherein the at least one dopant comprises poly(anetholesulfonate), poly(vinyl sulfate), p-toluene sulfonate, trifluoromethanesulfonate or a combination thereof.

29. The electrochromic device of claim 1, wherein the electrolyte permeable substrate layer is porous, perforated or a combination thereof.

30. The electrochromic device of claim 29, wherein the electrolyte permeable substrate layer comprises a microporous membrane having a pore size from at least about 0.01 μ

m to at least about 5.0 μ

m.

31. The electrochromic device of claim 30, wherein the microporous membrane has a pore size from at least about 0.05 μ

m to at least about 2.0 μ

m.

32. The electrochromic device of claim 1, wherein the electrolyte permeable substrate layer comprises poly(sulfone), poly(propylene), poly(ethylene terephthalate), poly(methyl methacrylate), poly(ethyl methacrylate), poly(tetrafluoroethylene) and other fluorinated poly(alkylenes), nylon, poly(vinylidene fluoride), acrylonitrile methyl acrylate copolymers, ethylene vinyl acetate, fluorinated ethylenepropylene resins, poly(carbonates), poly(butylenes), poly(vinyl chloride), poly(imides) or a combination thereof.

33. The electrochromic device of claim 1, wherein the electrolyte permeable substrate comprises poly(ethylene terephthalate), poly(tetrafluroethylene), poly(carbonates), poly(sulfones) or a combination thereof.

34. The electrochromic device of claim 1, wherein the electrolyte permeable substrate layer comprises woven synthetic textile cloth, nonwoven synthetic textile cloth, woven natural textile cloth, nonwoven natural textile cloth, paper or a combination thereof.

35. The electrochromic device of claim 1, wherein the conductive reflective layer comprises an IR reflecting material.

36. The electrochromic device of claim 35, wherein the IR reflecting material comprises a noble metal.

37. The electrochromic device of claim 36, wherein the IR reflecting metal is gold (Au), platinum (Pt) or a combination thereof.

38. The electrochromic device of claim 1, wherein the conductive reflective layer is porous, perforated or a combination thereof.

39. The electrochromic device of claim 1, comprising a flexible support layer.

40. The electrochromic device of claim 1, comprising a substantially IR transparent, outer layer comprising a solar-reflective coating.

41. The electrochromic device of claim 40, wherein the solar-reflective coating comprises germanium (Ge), silicon (Si), indium-tin oxide (ITO) or a combination thereof.

42. The electrochromic device of claim 41, wherein the outer layer comprises poly(ethylene), poly(propylene) or a combination thereof.

43. An activated IR-active, variable-emittance, electrochromic apparatus comprising:

(a) a working electrode comprising an IR-active conducting polymer matrix;

(b) a counter electrode in electrochemical communication with the working electrode;

(c) an ionic liquid electrolyte, said ionic liquid electrolyte contacting both the working electrode and the counter electrode; and

wherein the ionic liquid electrolyte is in electrochemical communication with the conducting polymer matrix such that the conducting polymer matrix is configured to undergo electrochemical reduction or oxidation upon application of an electric potential to the working electrode.

44. The apparatus of claim 43, wherein the working electrode comprises an IR reflector.

45. The apparatus of claim 44, wherein the conductive IR reflector comprises gold (Au), platinum (Pt) or a combination thereof.

46. The apparatus of claim 43, wherein the conducting polymer matrix comprises poly(aniline), poly(diphenyl amine), poly(4-amino biphenyl), poly(diphenylbenzidine), poly(3-alkyl thiophene) or a combination thereof.

47. The apparatus of claim 43, wherein the conducting polymer matrix is poly(aniline).

48. The apparatus of claim 43, wherein the working electrode comprises an electrolyte permeable substrate disposed between the working electrode and the counter electrode.

49. The apparatus of claim 43, wherein the electrolyte permeable substrate is porous, perforated or a combination thereof.

50. The apparatus of claim 49, wherein the electrolyte permeable substrate comprises a microporous membrane having a pore size from at least about 0.01 μ

m to at least about 5.0 μ

m.

51. The apparatus of claim 50, wherein the microporous membrane has a pore size from at least about 0.05 μ

m to at least about 2.0 μ

m.

52. The apparatus of claim 50, wherein the electrolyte permeable substrate comprises poly(sulfones), poly(propylene), poly(ethylene terephthalate), poly(methyl methacrylate), poly(ethyl methacrylate), poly(tetrafluoroethylene) and other fluorinated poly(alkylenes), nylon, poly(vinylidene fluoride), acrylonitrile methyl acrylate copolymers, ethylene vinyl acetate, fluorinated ethylenepropylene resins, poly(carbonates), poly(butylenes), poly(vinyl chloride), poly(imides) or a combination thereof.

53. The apparatus of claim 43, comprising a substantially IR transparent, outer layer comprising a solar-reflective coating.

54. The apparatus of claim 53, wherein the solar-reflective coating comprises germanium (Ge), silicon (Si), indium-tin oxide (ITO) or a combination thereof.

55. The apparatus of claim 53, wherein the outer layer comprises poly(ethylene), poly(propylene) or a combination thereof.

56. The apparatus of claim 43, wherein the ionic liquid comprises 1-butyl-3-methyl imidazoliumtetrafluoroborate (BMIM-BF₄), 1-butyl-3-methyl imidazoliumtrifluoro acetate, 1-ethyl-3-methyl imidazoliumtetrafluoroborate (EMIM-BF₄), 1-butyl-3-methylimidazolium trifluoromethanesulfonate, BMIM-bis(trifluoromethylsulfonyl)amide (BMIM-TF₂N), 1-(4-sulfobutyl)-3-methylimidazolium trifluoromethanesulfonate or a combination thereof.

57. The apparatus of claim 43, wherein the counter electrode comprises a second conducting polymer matrix.

58. The apparatus of claim 57, wherein the second conducting polymer matrix comprises poly(aniline), poly(diphenyl amine), poly(4-amino biphenyl), poly(diphenylbenzidine), poly(3-alkyl thiophene) or a combination thereof.

59. The apparatus of claim 43, wherein the IR active conducting polymer matrix comprises at least one dopant.

60. The apparatus of claim 59, wherein the at least one dopant comprises poly(anetholesulfonate), poly(vinyl sulfate), p-toluene sulfonate, trifluoromethanesulfonate or a combination thereof.

61. A method of preparing a variable emittance, electrochromic device for use in a high vacuum environment, comprising the steps of:

(a) providing at least one electrode having an electrolyte permeable substrate, a reflective conductive material, and an IR-active conducting polymer matrix;

wherein the step of providing the at least one electrode comprises providing an ionic liquid electrolyte and contacting the electrolyte permeable substrate with the ionic liquid electrolyte, wherein the ionic liquid electrolyte comprises 1-butyl-3-methyl imidazoliumtetrafluoroborate (BMIM-BF₄), 1-butyl-3-methyl imidazoliumtrifluoroacetate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methyl imidazoliumtetrafluoroborate (EMIM-BF₄), BMIM-bis(trifluoromethylsulfonyl)amide (BMIM-TF₂N), 1-(4-sulfobutyl)-3-methylimidazolium trifluoromethanesulfonate, or a combination thereof; and

(b) activating the at least one electrode to provide the variable emittance, electrochromic device.

62. The method of claim 61, wherein the step of providing the at least one electrode comprises providing the electrolyte permeable substrate.

63. The method of claim 62, wherein the step of providing the at least one electrode comprises depositing the reflective conducting material at the electrolyte permeable substrate.

64. The method of claim 63, wherein the step of providing the at least one electrode comprises preparing the IR-active conducting polymer matrix at the reflective conducting material.

65. The method of claim 64, wherein the electrolyte permeable substrate is porous.

66. The method of claim 64, wherein the reflective conducting material is porous.

67. The method of claim 61, wherein the ionic liquid electrolyte comprises tin (Sn).

68. The method of claim 61, wherein the step of providing the at least one electrode comprises heating the at least one electrode.

69. The method of claim 68, wherein the step of providing the at least one electrode comprises applying a potential to the at least one electrode.

70. The method of claim 61, wherein the step of providing the at least one electrode comprises voltammetric cycling to remove electrochemically inactive material from the conducting polymer matrix.

71. The method of claim 61, wherein the step of activating the at least one electrode comprises applying a potential to the at least one electrode.

72. The method of claim 71, wherein the step of applying a potential to the at least one electrode comprises applying a first potential corresponding to a reduced state of the IR-active conducting polymer matrix.

73. The method of claim 71, wherein the step of applying a potential to the at least one electrode comprises cycling the potential between a negative applied potential to a positive applied potential.

74. The method of claim 71, wherein the step of applying a potential to the at least one electrode comprises heating the at least one electrode.

75. The method of claim 61, wherein the step of providing the at least one electrode comprises incorporating a counterion of the ionic liquid electrolyte into the IR-active conducting polymer matrix.

76. The method of claim 61, wherein the step of providing the at least one electrode comprises the steps of:

(a) simultaneously heating and applying a potential to the at least one electrode;

(b) voltammetric cycling of the at least one electrode to remove electrochromically inactive material from the conducting polymer matrix; and

wherein the step of activating the at least one electrode to provide the variable emittance, electrochromic device comprises heating and applying a potential to the at least one electrode.

77. The method of claim 61, comprising providing a second electrode having a second conducting polymer matrix that is the same or different from the IR-active conducting polymer matrix.

78. The method of claim 77, comprising contacting the at least one electrode and second electrode with the ionic liquid electrolyte.

79. The method of claim 61, comprising providing a substantially IR-transparent outer layer.

80. A method of activating and providing a variable-emittance electrochromic electrode having an IR-active conducting polymer matrix and an ionic liquid having a counterion, comprising the steps of:

(a) applying a negative potential to the electrode that is sufficient to reduce the IR-active conducting polymer to a reduced state;

(b) heating the electrode to a temperature of at least about 70 C-210 C;

(c) applying a positive potential to the electrode that is sufficient to oxidize the IR-active conducting polymer to an oxidized state; and

(d) optionally, repeating steps (a) through (c) until the counterion of the ionic liquid is sufficiently incorporated into the IR-active polymer matrix.

81. The method of claim 80, wherein the reduced state is the fully reduced state of the IR-active conducting polymer.

82. The method of claim 80, wherein the oxidized state is the fully oxidized state of the IR-active conducting polymer.