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-niobium-oxide (NiWNbO). This material is particularly beneficial in that it is very transparent in its clear state.
1. A composition of matter comprising:
(a) nickel;
(b) tungsten;
(c) niobium; and
(d) oxygen,
wherein the composition comprises an atomic ratio of Ni:(W+Nb) that is between about 1.5:1 and 3:1, and
wherein the composition comprises an atomic ratio of W:Nb that is between about 0.2:1 and 1:1.
2. The composition of claim 1 , wherein the atomic ratio of Ni:(W+Nb) is between about 1.5:1 and 2.5:1.
3. The composition of claim 2 , wherein the atomic ratio of Ni:(W+Nb) is between about 1.8:1 and 2.5:1.
4. The composition of claim 3 , wherein the atomic ratio of Ni:(W+Nb) is between about 2:1 and 2.5:1.
5. The composition of claim 1 , wherein the atomic ratio of Ni:(W+Nb) is between about 2:1 and 3:1.
6. The composition of claim 1 , provided in a layer having a thickness between about 50-650 nm.
7. The composition of claim 1 , wherein the composition is formed through sputtering one or more sputter targets.
8. The composition of claim 1 , wherein the composition becomes tinted in response to an applied anodic potential.
9. The composition of claim 1 , wherein the composition is amorphous.
10. The composition of claim 1 , wherein the composition is provided as an amorphous matrix with nanocrystals distributed throughout.
11. The composition of claim 10 , wherein the nanocrystals have a mean diameter of about 50 nm or less.
12. The composition of claim 11 , wherein the nanocrystals have a mean diameter between about 1-10 nm.