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 forming an electrochromic device, the method comprising:
(a) depositing an electrochromic layer on a substrate;
(b) depositing a metal on the electrochromic layer, wherein the metal is lithium; and
(c) oxidizing at least a portion of the metal to form an ion conducting and electronically insulating material, wherein at least one of the following conditions is met:
(i) the electrochromic layer comprises tungsten oxide and the ion conducting and electronically insulating material comprises lithium tungstate,
(ii) the electrochromic layer comprises molybdenum oxide and the ion conducting and electronically insulating material comprises lithium molybdate,
(iii) the electrochromic layer comprises tantalum oxide and the ion conducting and electronically insulating material comprises lithium tantalate, and/or
(iv) the electrochromic layer comprises titanium oxide and the ion conducting and electronically insulating material comprises lithium titanate.
2. The method of claim 1 , wherein the electrochromic layer comprises tungsten oxide and the ion conducting and electronically insulating material comprises lithium tungstate.
3. The method of claim 1 , wherein the electrochromic layer comprises molybdenum oxide and the ion conducting and electronically insulating material comprises lithium molybdate.
4. The method of claim 1 , wherein the electrochromic layer comprises tantalum oxide and the ion conducting and electronically insulating material comprises lithium tantalate.
5. The method of claim 1 , wherein the electrochromic layer comprises titanium oxide and the ion conducting and electronically insulating material comprises lithium titanate.
6. A method of forming an electrochromic device, the method comprising:
(a) depositing an electrochromic layer on a substrate;
(b) depositing a metal on the electrochromic layer; and
(c) oxidizing at least a portion of the metal to form an ion conducting and electronically insulating material, wherein oxidizing at least the portion of the metal to form the ion conducting and electronically insulating material comprises exposing the substrate and/or the metal to oxygen.
7. The method of claim 6 , wherein the electrochromic layer comprises niobium oxide and the ion conducting and electronically insulating material comprises lithium niobate.
8. The method of claim 6 , wherein the electrochromic layer comprises zirconium oxide and the ion conducting and electronically insulating material comprises lithium zirconate.
9. The method of claim 6 , wherein the oxygen is provided as part of the electrochromic layer.
10. The method of claim 6 , further comprising depositing a counter electrode layer, wherein the oxygen is provided as part of the counter electrode layer.
11. The method of claim 6 , wherein the oxygen is provided as a superstoichiometric oxygen material on the substrate.
12. The method of claim 6 , wherein the oxygen is provided in an atmosphere to which the substrate is exposed.
13. The method of claim 6 , wherein oxidizing at least a portion of the metal to form the ion conducting and electronically insulating material comprises heating the substrate.
14. The method of claim 13 , wherein heating the substrate causes a reaction between the metal and a material of the electrochromic layer to form the ion conducting and electronically insulating material.
15. The method of claim 13 , further comprising depositing a counter electrode layer, wherein heating the substrate causes a reaction between the metal and a material of the counter electrode layer to form the ion conducting and electronically insulating material.
16. A method of forming an electrochromic device, the method comprising:
(a) depositing an electrochromic layer on a substrate;
(b) depositing a metal on the electrochromic layer;
(c) oxidizing at least a portion of the metal to form an ion conducting and electronically insulating material; and
(d) depositing a counter electrode layer, wherein at least one of the following conditions is met:
(i) oxidizing at least the portion of the metal to form the ion conducting and electronically insulating material occurs before depositing the counter electrode layer,
(ii) oxidizing at least the portion of the metal to form the ion conducting and electronically insulating material occurs while depositing the counter electrode layer, and/or
(iii) oxidizing at least the portion of the metal to form the ion conducting and electronically insulating material occurs after depositing the counter electrode layer.
17. The method of claim 16 , wherein the metal is lithium.
18. The method of claim 16 , wherein the ion conducting and electronically insulating material comprises at least one material selected from the group consisting of lithium tungstate (Li 2 WO 4 ), lithium molybdate (Li 2 MoO 4 ), lithium niobate (LiNbO 3 ), lithium tantalate (LiTaO 3 ), lithium titanate (Li 2 TiO 3 ), lithium zirconate (Li 2 ZrO 3 ), and combinations thereof.
19. The method of claim 16 , wherein oxidizing at least the portion of the metal to form the ion conducting and electronically insulating material occurs while depositing the counter electrode layer.
20. The method of claim 16 , wherein oxidizing at least the portion of the metal to form the ion conducting and electronically insulating material occurs after depositing the counter electrode layer.
21. The method of claim 16 , further comprising depositing additional metal on the counter electrode layer.
22. The method of claim 21 , wherein the additional metal is sufficient to fully bleach the counter electrode layer.
23. A method of forming an electrochromic device, the method comprising:
(a) depositing an electrochromic layer on a substrate;
(b) depositing a metal on the electrochromic layer; and
(c) oxidizing at least a portion of the metal to form an ion conducting and electronically insulating material, wherein (a) and (b) are performed while under vacuum, and wherein the vacuum is not broken between (a) and (b).
24. The method of claim 23 , wherein the metal is selected from the group consisting of lithium, sodium, potassium, calcium, barium, strontium, magnesium, and combinations thereof.