Counter electrode for electrochromic devices
The embodiments herein relate to electrochromic stacks, electrochromic devices, and methods and apparatus for making such stacks and devices. In various embodiments, an anodically coloring layer in an electrochromic stack or device is fabricated to include nickel-tungsten-tin-oxide (NiWSnO). This material is particularly beneficial in that it is very transparent in its clear state.
1. A method of fabricating an electrochromic stack, the method comprising:
forming a cathodically coloring layer comprising a cathodically coloring electrochromic material; and
forming an anodically coloring layer comprising nickel-tungsten-tin-oxide (NiWSnO).
2. The method of claim 1 , wherein the NiWSnO comprises an atomic ratio of Ni:(W+Sn) that is between about 1:1 and 4:1.
3. The method of claim 2 , wherein the NiWSnO comprises an atomic ratio of Ni:(W+Sn) that is between about 1:1 and 3:1.
4. The method of claim 3 , wherein the NiWSnO comprises an atomic ratio of Ni:(W+Sn) that is between about 1.5:1 and 2.5:1.
5. The method of claim 1 , wherein the NiWSnO comprises an atomic ratio of W:Sn that is between about 1:9 and 9:1.
6. The method of claim 5 , wherein the NiWSnO comprises an atomic ratio of W:Sn that is between about 1:1 and 3:1.
7. The method of claim 1 , wherein the NiWSnO comprises an atomic ratio of W:Sn that is between about 1.5:1 and 2:1.
8. The method of claim 1 , wherein forming the anodically coloring layer comprises sputtering one or more sputter targets to form the NiWSnO.
9. The method of claim 8 , wherein at least one of the one or more of the sputter targets comprise an elemental metal selected from the group consisting of: nickel, tungsten, and tin.
10. The method of claim 8 , wherein at least one of the one or more of the sputter targets comprise an alloy comprising two or more metals selected from the group consisting of: nickel, tungsten, and tin.
11. The method of claim 8 , wherein at least one of the one or more of the sputter targets comprise an oxide.
12. The method of claim 1 , wherein the anodically coloring layer is substantially amorphous.
13. The method of claim 1 , wherein the cathodically coloring layer and the anodically coloring layer are formed in direct physical contact with one another, without a separate ion conductor layer deposited between them.
14. The method of claim 1 , wherein the cathodically coloring layer comprises tungsten oxide, optionally doped with one or more dopants selected from the group consisting of molybdenum, vanadium, and titanium.
15. The method of claim 13 , wherein at least one of the cathodically coloring layer and the anodically coloring layer comprises an oxygen-rich portion, the method further comprising:
lithiating at least one of the cathodically coloring layer and the anodically coloring layer; and
heating the electrochromic stack to form an interfacial region that is ion conducting and electronically insulating between the cathodically coloring layer and the anodically coloring layer.
16. An electrochromic stack, comprising:
a cathodically coloring layer comprising a cathodically coloring material; and
an anodically coloring layer comprising nickel-tungsten-tin-oxide (NiWSnO).
17. The electrochromic stack of claim 16 , wherein the NiWSnO comprises an atomic ratio of Ni:(W+Sn) that is between about 1:1 and 4:1.
18. The electrochromic stack of claim 17 , wherein the NiWSnO comprises an atomic ratio of Ni:(W+Sn) that is between about 1:1 and 3:1.
19. The electrochromic stack of claim 18 , wherein the NiWSnO comprises an atomic ratio of Ni:(W+Sn) that is between about 1.5:1 and 2.5:1.
20. The electrochromic stack of claim 16 , wherein the NiWSnO comprises an atomic ratio of W:Sn that is between about 1:9 and 9:1.
21. The electrochromic stack of claim 20 , wherein the NiWSnO comprises an atomic ratio of W:Sn that is between about 1:1 and 3:1.
22. The electrochromic stack of claim 16 , wherein the NiWSnO comprises an atomic ratio of W:Sn that is between about 1.5:1 and 2:1.
23. The electrochromic stack of claim 16 , wherein the anodically coloring layer is substantially amorphous.
24. The electrochromic stack of claim 16 , wherein the cathodically coloring layer is in direct physical contact with the anodically coloring layer.
25. The electrochromic stack of claim 16 , wherein the cathodically coloring layer comprises tungsten oxide, optionally doped with one or more dopants selected from the group consisting of molybdenum, vanadium, and titanium.