Electrochromic devices
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.
1. A method of fabricating a single layer EC element on a substrate in a sputter system, the method comprising:
(a) sputter coating an EC material including a first transition metal and a first oxygen concentration onto the substrate;
(b) increasing from the first oxygen concentration to a second oxygen concentration, higher than the first oxygen concentration, during (a);
(c) introducing lithium into the sputter system; and
(d) sputter coating a CE material including a second transition metal and oxygen;
wherein the fabrication is a substantially continuous process and a concentration of the first transition metal is decreased from (a) to (d), and a concentration of the second transition metal is increased from (a) to (d).
2. The method of claim 1 , wherein the first transition metal is tungsten.
3. The method of claim 1 , wherein the second transition metal is nickel.
4. The method of claim 1 , wherein introducing lithium into the sputter system comprises sputtering a lithium compound target.
5. The method of claim 4 , wherein the lithium compound target comprises lithium tungstate.
6. A method of fabricating an EC element on a substrate, the EC element comprising five successive functional regions: a first transparent conductor region, a cathodically coloring electrochromic region, an ion conducting region, an anodically coloring electrochromic region and a second transparent conductor region; the method comprising substantially continuous sputtering during formation of the five successive functional regions.
7. The method of claim 6 , wherein the substantially continuous process sputtering comprises sputter coating materials from a plurality of closely associated sputter targets such that there is mixing of materials sputtered from each sputter target in the region where two sputter targets are proximate each other.
8. The method of claim 7 , wherein the EC element is a single layer EC element and is fabricated upon a single pass of the substrate and the plurality of closely associated sputter targets past each other.
9. The method of claim 7 , wherein the plurality of closely associated sputter targets comprises a sputter target comprising an EC material, a sputter target comprising an IC material and a sputter target comprising a CE material.
10. The method of claim 9 , wherein the EC material comprises tungsten oxide.
11. The method of claim 9 , wherein the IC material comprises lithium tungstate.
12. The method of claim 9 , wherein the CE material comprises nickel tungsten oxide.