ELECTROCHROMIC DEVICES

• US 20100245973A1
• Filed: 12/22/2009
• Published: 09/30/2010
• Est. Priority Date: 03/31/2009
• Status: Active Grant

• Current Assignee: View Incorporated
• Original Assignee: Soladigm, Inc. (View Incorporated)
• Inventors: Scobey, Mike, Dixon, Jeremy, Kurman, Eric, Wang, Zhongchun, Kozlowski, Mark, Pradhan, Anshu
• Granted Patent: US 8,432,603 B2
• Time in Patent Office: Days
• US Class Current: 359/275
• CPC Class Codes: B05D 5/06 to obtain multicolour or other optical effects B05D5/02 takes precedence
• CPC Class Codes: B23K 20/10 making use of vibrations, e.g. ultrasonic welding
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2217/94 Transparent conductive oxide layers [TCO] being part of a multilayer coating
• CPC Class Codes: C09K 2211/183 of the refractory metals, i.e. Ti, V, Cr, Zr, Nb, Mo, Hf, Ta or W
• CPC Class Codes: C09K 2211/187 of the iron group metals, i.e. Fe, Co or Ni
• CPC Class Codes: C09K 9/00 Tenebrescent materials, i.e. materials for which the range of wavelengths for energy absorption is changed as a result of excitation by some form of energy
• CPC Class Codes: C23C 10/28 using solids, e.g. powders, pastes
• CPC Class Codes: C23C 14/021 Cleaning or etching treatments
• CPC Class Codes: C23C 14/022 by means of bombardment with energetic particles or radiation
• CPC Class Codes: C23C 14/024 Deposition of sublayers, e.g. to promote adhesion of the coating C23C14/027 takes precedence
• CPC Class Codes: C23C 14/046 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence
• CPC Class Codes: C23C 14/083 of refractory metals or yttrium
• CPC Class Codes: C23C 14/085 of iron group metals
• CPC Class Codes: C23C 14/086 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: C23C 14/14 Metallic material, boron or silicon
• CPC Class Codes: C23C 14/185 by cathodic sputtering
• CPC Class Codes: C23C 14/3407 Cathode assembly for sputtering apparatus, e.g. Target
• CPC Class Codes: C23C 14/568 Transferring the substrates through a series of coating stations C23C14/562 takes precedence
• CPC Class Codes: C23C 14/58 : After-treatment
• CPC Class Codes: C23C 14/5806 : Thermal treatment
• CPC Class Codes: C23C 14/5853 : Oxidation
• CPC Class Codes: G02F 1/1524 : Transition metal compounds
• CPC Class Codes: G02F 1/1525 : characterised by a particular ion transporting layer, e.g. electrolyte
• CPC Class Codes: G02F 1/153 : Constructional details
• CPC Class Codes: G02F 1/1533 : structural features not otherwise provided for
• CPC Class Codes: G02F 1/155 : Electrodes
• CPC Class Codes: G02F 2001/1536 : additional, e.g. protective, layer inside the cell

Abstract

Prior electrochromic devices frequently suffer from poor reliability and poor performance. Some of the difficulties result from inappropriate design and construction of the devices. In order to improve device reliability two layers of an electrochromic device, the counter electrode layer and the electrochromic layer, can each be fabricated to include defined amounts of lithium. Further, the electrochromic device may be subjected to a multistep thermochemical conditioning operation to improve performance. Additionally, careful choice of the materials and morphology of some components of the electrochromic device provides improvements in performance and reliability. In some devices, all layers of the device are entirely solid and inorganic.

Claims

1. An electrochromic window comprising:

(a) an architectural glass substrate; and

(b) a stack disposed on said substrate, the stack comprising a (i) a tungsten oxide electrochromic layer, (ii) a solid inorganic lithium ion conducting layer, and (iii) a nickel tungsten oxide counter electrode layer, wherein the ion conducting layer separates the electrochromic layer and the counter electrode layer,

wherein the electrochromic window has fewer than about 0.045 total visible defects per square centimeter in any region of electrochromic active area.

2. The electrochromic window of claim 1, wherein the electrochromic layer comprises WO_x, wherein x is less than 3.0 and at least 2.7.

3. The electrochromic window of claim 1, wherein the tungsten oxide has a substantially nanocrystalline morphology.

4. The electrochromic window of claim 1, wherein the electrochromic layer has a thickness of between about 200 nm and about 700 nm.

5. The electrochromic window of claim 1, wherein the electrochromic layer and the counter electrode layer each comprise lithium ions.

6. The electrochromic window of claim 1, wherein the ion conducting layer comprises a silicon aluminum oxide.

7. The electrochromic window of claim 1, wherein the ion conducting layer has a thickness of between about 10 nm and about 100 nm.

8. The electrochromic window of claim 1, wherein the counter electrode layer has a thickness of between about 150 nm and about 350 nm.

9. The electrochromic window of claim 1, wherein the ratio of thicknesses of the electrochromic layer to the counter electrode layer is between about 1.7:

1 and 2.3;

1.

10. The electrochromic window of claim 1, further comprising a first layer of transparent conductive oxide in electrical contact with the electrochromic layer and a second layer of transparent conductive oxide in electrical contact with the counter electrode layer.

11. The electrochromic window of claim 10, wherein each layer of transparent conductive oxide has a sheet resistance of between about 5 ohms/square and about 30 ohms/square.

12. The method of claim 10, wherein the stack includes two layers of transparent conductive oxide, one for electronic contact with the electrochromic layer and the other for electronic contact with the counter electrode layer, and wherein the two layers of transparent conductive oxide have substantially the same sheet resistance.

13. The electrochromic window of claim 1, wherein the architectural glass substrate has a width of at least about 20 inches.

14. The electrochromic window of claim 1, wherein the window has fewer than about 0.04 visible pinhole defects per square centimeter of the electrochromic window.

15. The electrochromic window of claim 1, wherein window has fewer than about 0.005 visible short-type defects per square centimeter of the electrochromic window.

16. The electrochromic window of claim 1, wherein the window has a number of non-visible short-type defects that produce a leakage current of less than about 5 μ

A/cm² at ±

2V bias of the electrochromic window.

17. A method of fabricating an electrochromic device on a substrate, the method comprising:

(a) depositing an electrochromic layer;

(b) lithiating the electrochromic layer;

(c) depositing an ion conducting layer;

(d) depositing a counter electrode layer for reversibly exchanging lithium ions with the electrochromic layer during operation of the electrochromic window; and

(e) lithiating the counter electrode layer,

wherein (a)-(e) produces a stack on the substrate in which the ion conducting layer separates the electrochromic layer and the counter electrode layer.

18. The method of claim 17, wherein lithiating the electrochromic layer comprise depositing lithium directly on the electrochromic layer.

19. The method of claim 17, wherein lithiating the counter electrode layer comprise depositing lithium directly on the counter electrode layer.

20. The method of claim 17, wherein operations (d) and (e) are performed prior to operation (c) and operations (a) and (b) are performed after operation (c).

21. The method of claim 17, wherein the electrochromic layer comprises WO_x, wherein x is less than 3.0 and at least 2.7.

22. The method of claim 21, wherein the WO_x has a substantially nanocrystalline morphology.

23. The method of claim 17, wherein the counter electrode layer comprises a nickel tungsten oxide.

24. The method of claim 23, wherein the per mass amount of lithium deposited on the counter electrode layer in (d) is between about 1.5 and 2.5 times the per mass amount of lithium deposited on the electrochromic layer in (b).

25. The method of claim 17, wherein depositing lithium directly on the electrochromic layer deposits an amount of lithium that is at least sufficient to compensate substantially all blind charge in the electrochromic layer.

26. The method of claim 17, wherein the lithium deposited in one or both of operations (b) and (d) is physical vapor deposited.

27. The method of claim 26, wherein the physical vapor deposited lithium in at least one of operations (b) and (d) is deposited from two or more lithium targets serially offset from one another along a path taken by the substrate in an integrated deposition system.

28. The method of claim 26, wherein the physical vapor deposited lithium in at least one of operations (b) and (d) is deposited is deposited while the substrate moves back and forth within a lithium deposition station.

29. The method of claim 17, wherein the lithium deposited in one or both of operations (b) and (d) is performed at a rate that is sufficiently slow to allow the deposited lithium to substantially incorporate within the electrochromic layer or the counter electrode layer prior to completion of the lithium deposition operation.

30. The method of claim 17, the thicknesses of the electrochromic and counter electrode layers do not change by more than about 4%, during electrochemical cycling of the electrochromic device, from their as deposited, post-lithiation thicknesses.

31. The method of claim 17, wherein each of the electrochromic layer, the ion conducting layer, and the counterelectrode layer is a solid phase layer.

32. The method of claim 17, wherein each of the electrochromic layer, the ion conducting layer, and the counterelectrode layer is comprised solely of inorganic material.

33. The method of claim 17, wherein depositing the electrochromic layer comprises depositing the electrochromic layer to a thickness of between about 200 nm and about 700 nm.

34. The method of claim 17, wherein depositing the ion conducting layer comprises depositing a material selected from the group consisting of a tungsten oxide, a tantalum oxide, a niobium oxide, and a silicon aluminum oxide.

35. The method of claim 17, wherein depositing the ion conducting layer comprises depositing the ion conducting layer to a thickness of between about 10 nm and about 100 nm.

36. The method of claim 17, wherein depositing the counter electrode layer comprises depositing a layer of nickel tungsten oxide.

37. The method of claim 36, wherein the layer of nickel tungsten oxide is substantially amorphous.

38. The method of claim 36, wherein depositing the counter electrode layer comprises sputtering a target comprising about 10 to about 40 atomic % of tungsten in nickel in an oxygen containing environment to produce the layer of nickel tungsten oxide.

39. The method of claim 17, wherein depositing the counter electrode layer comprises depositing the counter electrode layer to a thickness of between about 150 nm and about 350 nm.

40. The method of claim 17, wherein the electrochromic layer comprises tungsten oxide and the counter electrode comprises nickel tungsten oxide, and wherein the ratio of thicknesses of the electrochromic layer to the counter electrode layer is between about 1.7:

1 and 2.3;

1.

41. The method of claim 17, further comprising depositing a layer of transparent conductive oxide on the stack.

42. The method of claim 17, wherein the substrate comprises architectural glass.

43. The method of claim 17, wherein the substrate has a width of at least about 20 inches.

44. The method of claim 17, wherein method is performed under conditions that produce fewer than about 0.04 visible pinhole defects per square centimeter of the electrochromic window.

45. The method of claim 17, wherein method is performed under conditions that produce fewer than about 0.005 visible short-type defects per square centimeter of the electrochromic window.

46. The method of claim 17, wherein method is performed under conditions that produce a number of non-visible short-type defects that result in a leakage current of less than about 5 μ

A/cm² at ±

2V bias of the electrochromic window.

47. An electrochromic window comprising:

(a) an architectural glass substrate; and

(b) a stack disposed on said substrate, the stack comprising a (i) a tungsten oxide electrochromic layer, (ii) a solid and inorganic lithium ion conducting layer, and (iii) a substantially amorphous nickel tungsten oxide counter electrode layer, wherein the ion conducting layer separates the electrochromic layer and the counter electrode layer.

48. The electrochromic window of claim 47, wherein the solid and inorganic lithium ion conducting layer comprises a silicon aluminum oxide.

49. The electrochromic window of claim 47, wherein the electrochromic window has fewer than about 0.2 total visible defects per square cm of electrochromic active area.

50. The electrochromic window of claim 47, wherein the substantially amorphous nickel tungsten oxide in the counter electrode layer has an atomic ratio of tungsten to nickel of between about 0.15 to 0.35.

51. The electrochromic window of claim 47, wherein the counter electrode layer has a thickness of between about 150 nm and about 350 nm.

52. The electrochromic window of claim 47, wherein the ratio of thicknesses of the electrochromic layer to the counter electrode layer is between about 1.7:

1 and 2.3;

1.

53. The electrochromic window of claim 47, wherein the electrochromic layer comprises WO_x, wherein x is less than 3.0 and at least 2.7.

54. The electrochromic window of claim 53, wherein the WO_x has a substantially nanocrystalline morphology.

55. The electrochromic window of claim 47, wherein the electrochromic layer has a thickness of between about 200 nm and about 700 nm.

56. The electrochromic window of claim 47, wherein the ion conducting layer has an atomic ratio of silicon to aluminum of between about 5:

1 and 20;

1.

57. The electrochromic window of claim 47, wherein the ion conducting layer has a thickness of between about 10 nm and about 100 nm.

58. The electrochromic window of claim 47, further comprising a first layer of transparent conductive oxide in electrical communication with the electrochromic layer and a second layer of transparent conductive oxide in electrical communication with the counter electrode layer.

59. The electrochromic window of claim 58, wherein each layer of transparent conductive oxide has a sheet resistance of between about 5 ohms/square and about 30 ohms/square.

60. The electrochromic window of claim 58, wherein the stack includes two layers of transparent conductive oxide, one for electronically contacting the electrochromic layer and the other for electronically contacting the counter electrode layer, and wherein the two layers of transparent conductive oxide have substantially the same sheet resistance.

61. The electrochromic window of claim 47, wherein the architectural glass substrate has a width of at least about 20 inches.

62. A method of fabricating an electrochromic window, the method comprising:

sequentially depositing on a substrate (i) a tungsten oxide electrochromic layer, (ii) an inorganic and solid lithium ion conducting layer, and (iii) a substantially amorphous nickel tungsten oxide counter electrode layer to form a stack in which the ion conducting layer separates the electrochromic layer and the counter electrode layer.

63. The method of claim 62, wherein each of the sequentially deposited layers is deposited using a single integrated deposition system, and wherein the substrate does not leave the integrated deposition system at any time during the sequential deposition of the electrochromic layer, the ion conducting layer, and the counter electrode layer.

64. The method of claim 62, wherein depositing the substantially amorphous nickel tungsten oxide counter electrode layer produces a nickel tungsten oxide in which the atomic ratio of tungsten to nickel is between about 0.15 to 0.35.

65. The method of claim 62, wherein depositing the ion conducting layer produces a silicon aluminum oxide in which the atomic ratio of silicon to aluminum of between about 5:

1 and 20;

1.

66. The method of claim 62, wherein the electrochromic layer comprises WO_x, wherein x is less than 3.0 and at least 2.7.

67. The method of claim 66, wherein the WO_x has a substantially nanocrystalline morphology.

68. The method of claim 62, wherein each of (i) the tungsten oxide electrochromic layer, (ii) the inorganic and solid lithium ion conducting layer, and (iii) the substantially amorphous nickel tungsten oxide counter electrode layer is physical vapor deposited.

69. The method of claim 67, wherein depositing the counter electrode layer comprises sputtering a target comprising about 10 to about 40 atomic % of tungsten in nickel in an oxygen containing environment to produce the layer of nickel tungsten oxide.

70. The method of claim 62, wherein depositing the counter electrode layer comprises depositing the counter electrode layer to a thickness of between about 150 nm and about 350 nm.

71. The method of claim 62, wherein the ratio of thicknesses of the electrochromic layer to the counter electrode layer is between about 1.7:

1 and 2.3;

1.

72. The method of claim 62, wherein depositing the counter electrode layer comprises depositing nickel tungsten oxide at a pressure of between about 1 mTorr and about 50 mTorr.

73. The method of claim 62, further comprising depositing a layer of transparent conductive oxide on the stack.

74. The method of claim 62, wherein the substrate comprises architectural glass.

75. A method of fabricating an electrochromic window, the method comprising:

(a) sequentially depositing on a substrate (i) a solid inorganic electrochromic layer, (ii) a solid inorganic ion conducting layer, and (iii) a solid inorganic counter electrode layer to form a stack in which the ion conducting layer separates the electrochromic layer and the counter electrode layer; and

(b) performing a multistep thermochemical conditioning comprising heating the stack in an environment substantially free of components that react with one or more layers in the stack, and heating the stack in an environment comprising an agent that reacts with one or more layers in the stack.

76. The method of claim 75, wherein performing a multistep thermochemical conditioning comprises (i) heating the stack in an inert environment, (ii) heating the stack in a controlled environment containing oxygen, and (iii) heating in air.

77. The method of claim 75, wherein each of the sequentially deposited layers is deposited using a single integrated deposition system, and wherein the substrate does not leave the integrated deposition system at any time during the sequential deposition of the electrochromic layer, the ion conducting layer, and the counter electrode layer.

78. The method of claim 77, wherein at least one of the operations in the multistep thermochemical conditioning is performed outside the integrated deposition system.

79. The method of claim 78, wherein the substrate is removed from the integrated deposition system at a temperature of at least about 80°

C. and subsequently heated in air.