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, which are in direct contact with one another. 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. In addition to the improved electrochromic devices and methods for fabrication, integrated deposition systems for forming such improved devices are also disclosed.
1. A method of fabricating an electrochromic device, the method comprising:
(a) depositing a tungsten oxide based electrochromic material layer onto a substrate; the tungsten oxide based electrochromic material layer comprising a portion that is oxygenated to a superstoichiometric level;
(b) depositing a nickel oxide based counter electrode material layer directly onto the tungsten oxide based electrochromic layer;
(c) depositing lithium on the nickel oxide based counter electrode material layer; and then
(d) heating the substrate to form an electronically insulating and ionically conductive material at the interface between the tungsten oxide based electrochromic material layer and the nickel oxide based counter electrode material layer.
2. The method of claim 1 , wherein (a) comprises sputtering a tungsten target in a first atmosphere of oxygen and inert gas.
3. The method of claim 2 , where the first atmosphere of oxygen and inert gas comprises between about 70% and about 100% O 2 .
4. The method of claim 1 , wherein (b) comprises sputtering a nickel target in a second atmosphere of oxygen and inert gas.
5. The method of claim 1 , wherein (c) comprises sputtering lithium in an inert atmosphere.
6. The method of claim 1 , wherein (d) comprises heating the substrate to between about 100° C. and about 450° C.
7. The method of claim 1 , wherein the tungsten oxide based electrochromic material layer is tungsten oxide.
8. The method of claim 1 , wherein the tungsten oxide based electrochromic material layer comprises tungsten molybdenum oxide.
9. The method of claim 1 , wherein the tungsten oxide based electrochromic material layer comprises tungsten niobium oxide.
10. The method of claim 1 , wherein the tungsten oxide based electrochromic material layer comprises tungsten vanadium oxide.
11. The method of claim 1 , wherein the tungsten oxide based electrochromic material layer comprises tungsten titanium oxide.
12. The method of claim 1 , wherein the nickel oxide based counter electrode material layer comprises nickel tungsten oxide.
13. The method of claim 12 , wherein the nickel oxide based counter electrode material layer is substantially amorphous.
14. The method of claim 12 , wherein the nickel oxide based counter electrode material layer comprises tantalum.
15. The method of claim 14 , wherein the nickel oxide based counter electrode material layer is substantially amorphous.
16. The method of claim 1 , further comprising depositing a transparent conductive oxide material layer on the substrate after (c).
17. The method of claim 16 , wherein the transparent conductive oxide material layer comprises indium tin oxide.
18. The method of claim 1 , wherein (a) further comprises heating the substrate to between about 150° C. and about 450° C.
19. A method of fabricating an electrochromic device, the method comprising:
(i) depositing a first electrochromic material layer of formula MO x onto a substrate, wherein M is a metal and the value of x is a number equal to a stoichiometric amount of oxygen for the metal;
(ii) depositing a second electrochromic material layer of formula NO y directly onto the first electrochromic material layer, where N is the metal or a different metal and the value of y is a number equal to a superstoichiometric amount of oxygen for the metal or the different metal;
(iii) depositing a nickel oxide based counter electrode material layer directly onto the second electrochromic material layer;
(iv) depositing lithium on the nickel oxide based counter electrode material; and then
(v) heating the substrate to form an electronically insulating and ionically conductive material at the interface between the second electrochromic material layer and the nickel oxide based counter electrode material layer.
20. The method of claim 19 , wherein M and N are both tungsten.
21. The method of claim 19 , wherein M is tungsten and N is selected from the group consisting of niobium, silicon, tantalum, titanium, zirconium, and cerium.
22. The method of claim 19 , wherein (iii) comprises sputtering a nickel target in an atmosphere of oxygen and inert gas.
23. The method of claim 19 , wherein (iv) comprises sputtering lithium in an inert atmosphere.
24. The method of claim 19 , wherein (v) comprises heating the substrate to between about 150° C. and about 450° C.
25. The method of claim 19 , wherein the nickel oxide based counter electrode material layer comprises nickel tungsten oxide.
26. The method of claim 25 , wherein the nickel oxide based counter electrode material layer is substantially amorphous.
27. The method of claim 25 , wherein the nickel oxide based counter electrode material layer comprises tantalum.
28. The method of claim 27 , wherein the nickel oxide based counter electrode material layer is substantially amorphous.
29. The method of claim 19 , further comprising depositing a transparent conductive oxide material layer on the substrate after (iv).
30. The method of claim 19 , where (ii) is performed in an atmosphere comprising between about 70% and about 100% O 2 .
31. The method of claim 19 , wherein (i) further comprises heating the substrate to between about 150° C. and about 450° C.