Electrochromic devices

• US 8,300,298 B2
• Filed: 04/30/2010
• Issued: 10/30/2012
• Est. Priority Date: 04/30/2010
• Status: Active Grant

• Current Assignee: View Incorporated
• Original Assignee: Soladigm, Inc.
• Inventors: Wang, Zhongchun, Pradhan, Anshu, Rozbicki, Robert
• Primary Examiner(s): Tra, Tuyen
• Application Number:
  US12/772,055
• Publication Number:
  US 20110267674A1
• Time in Patent Office: 914 Days
• Field of Search: 359265-275
• US Class Current: 359/273
• CPC Class Codes: B32B 17/10513 Electrochromic layer
• CPC Class Codes: C23C 14/083 of refractory metals or yttrium
• CPC Class Codes: C23C 14/088 of the type ABO3 with A representing alkali, alkaline earth metal or Pb and B representing a refractory or rare earth metal
• CPC Class Codes: C23C 14/185 by cathodic sputtering
• CPC Class Codes: C23C 14/34 Sputtering
• CPC Class Codes: C23C 14/548 Controlling the composition
• CPC Class Codes: C23C 14/568 Transferring the substrates through a series of coating stations C23C14/562 takes precedence
• CPC Class Codes: E06B 3/6722 with adjustable passage of light
• CPC Class Codes: G02F 1/1525 characterised by a particular ion transporting layer, e.g. electrolyte
• CPC Class Codes: G02F 2001/1555 Counter electrode

Abstract

Conventional electrochromic devices frequently suffer from poor reliability and poor performance. Improvements are made using entirely solid and inorganic materials. Electrochromic devices are fabricated by forming an ion conducting electronically insulating interfacial region that serves as an IC layer. In some methods, the interfacial region is formed after formation of an electrochromic and a counter electrode layer. The interfacial region contains an ion conducting electronically insulating material along with components of the electrochromic and/or the counter electrode layer. Materials and microstructure of the electrochromic devices provide improvements in performance and reliability over conventional devices.

Claims

1. A method of fabricating an electrochromic device, the method comprising:

(a) forming either an electrochromic layer including an electrochromic material or a counter electrode layer including a counter electrode material;

(b) forming an intermediate layer over the electrochromic layer or the counter electrode layer, where the intermediate layer includes an oxygen rich form of at least one of the electrochromic material, the counter electrode material, and an additional material, where the additional material includes distinct electrochromic or counter electrode material, the intermediate layer in a state that is not substantially electronically insulating;

(c) forming the other of the electrochromic layer and the counter electrode layer; and

(d) converting at least a portion of the intermediate layer from the state that is not substantially electronically insulating to a state that is substantially electronically insulating.

2. The method of claim 1, wherein the electrochromic material is WO₃.

3. The method of claim 1, wherein (a) comprises forming the electrochromic layer via sputtering WO₃ using a tungsten target and a first sputter gas comprising between about 40% and about 80% O₂ and between about 20% Ar and about 60% Ar, to reach a thickness of between about 350 nm and about 450 nm, and heating, at least intermittently, to between about 150°

C. and about 450°

C. during formation of the electrochromic layer.

4. The method of claim 3, wherein (b) comprises sputtering WO₃ using a tungsten target and a second sputter gas comprising between about 70% and 100% O₂ and between 0% Ar and about 30% Ar, to reach a thickness of between about 10 nm and about 200 nm, without heating.

5. The method of claim 1, further comprising sputtering lithium onto the intermediate layer until the blind charge is satisfied.

6. The method of claim 1, wherein the counter electrode layer comprises NiWO, between about 150 nm and about 300 nm thick.

7. The method of claim 6, wherein the NiWO is substantially amorphous.

8. The method of claim 1, further comprising sputtering lithium onto the counter electrode layer until the counter electrode layer is substantially bleached.

9. The method of claim 8, further comprising sputtering an additional amount of lithium, between about 5% and about 15% excess based on the quantity required to bleach the counter electrode layer, onto the counter electrode layer.

10. The method of claim 1, further comprising depositing a transparent conducting oxide layer on top of the counter electrode layer.

11. The method of claim 10, wherein the transparent conducting oxide comprises indium tin oxide.

12. The method of claim 10, further comprising heating the stack formed, before or after depositing the transparent conducting oxide, at between about 150°

C. and about 450°

C., for between about 10 minutes and about 30 minutes under Ar, and then for between about 1 minute and about 15 minutes under O₂.

13. The method of claim 1, further comprising heating the stack formed in air at between about 250°

C. and about 350°

C., for between about 20 minutes and about 40 minutes.

14. The method of claim 1, further comprising flowing a current between the electrochromic layer and the counter electrode layer as part of an initial activation cycle of the electrochromic device.