Fabrication of electrochromic devices
Electrochromic devices and methods may employ the addition of a defect-mitigating insulating layer which prevents electronically conducting layers and/or electrochromically active layers from contacting layers of the opposite polarity and creating a short circuit in regions where defects form. In some embodiments, an encapsulating layer is provided to encapsulate particles and prevent them from ejecting from the device stack and risking a short circuit when subsequent layers are deposited. The insulating layer may have an electronic resistivity of between about 1 and 10 8 Ohm-cm. In some embodiments, the insulating layer contains one or more of the following metal oxides: aluminum oxide, zinc oxide, tin oxide, silicon aluminum oxide, cerium oxide, tungsten oxide, nickel tungsten oxide, and oxidized indium tin oxide. Carbides, nitrides, oxynitrides, and oxycarbides may also be used.
1. An electrochromic stack comprising:
an electrochromic layer and a counter electrode layer; and
a second layer positioned on or within the electrochromic layer or on or within the counter electrode layer,
wherein a change in optical density or transmissivity of the second layer when a voltage is applied is less than a change in optical density or transmissivity of the electrochromic layer when the voltage is applied,
wherein the second layer comprises a metal oxynitride, and
wherein the metal oxynitride comprises a metal selected from the group consisting of titanium, tungsten, and tantalum.
2. The electrochromic stack of claim 1 , wherein the second layer is positioned on or within the electrochromic layer.
3. The electrochromic stack of claim 2 , wherein the electrochromic layer comprises a metal oxide selected from the group consisting of: tungsten oxide, molybdenum oxide, niobium oxide, titanium oxide, vanadium oxide, and combinations thereof.
4. The electrochromic stack of claim 3 , wherein the metal oxide in the electrochromic layer is doped with one or more dopants selected from the group consisting of: lithium, sodium, potassium, molybdenum, vanadium, titanium, and combinations thereof.
5. The electrochromic stack of claim 1 , wherein the second layer is positioned on or within the counter electrode layer.
6. The electrochromic stack of claim 5 , wherein the counter electrode layer comprises a metal oxide selected from the group consisting of: tungsten oxide, molybdenum oxide, niobium oxide, titanium oxide, copper oxide, iridium oxide, chromium oxide, manganese oxide, vanadium oxide, nickel oxide, cobalt oxide, and combinations thereof.
7. The electrochromic stack of claim 6 , wherein the metal oxide in the counter electrode layer is doped with one or more dopants selected from the group consisting of:
tantalum and tungsten.
8. The electrochromic stack of claim 1 , wherein the metal oxynitride in the second layer comprises two metals.
9. The electrochromic stack of claim 8 , wherein one of the metals in the metal oxynitride in the second layer is titanium.
10. The electrochromic stack of claim 8 , wherein one of the metals in the metal oxynitride in the second layer is tantalum.
11. The electrochromic stack of claim 8 , wherein one of the metals in the metal oxynitride in the second layer is tungsten.
12. The electrochromic stack of claim 1 , wherein a thickness of the second layer is between about 5-500 nm.
13. The electrochromic stack of claim 12 , wherein the thickness of the second layer is between about 5-100 nm.
14. The electrochromic stack of claim 1 , wherein the second layer is positioned on or within the counter electrode layer, and wherein the counter electrode layer and the second layer comprise different forms of the same metal oxide.
15. The electrochromic stack of claim 14 , wherein the counter electrode layer and the second layer comprise different forms of nickel tungsten oxide.
16. The electrochromic stack of claim 1 , wherein the second layer reduces degradation in the stack.
17. An electrochromic device comprising:
a first electrode layer;
an ion conducting layer;
the electrochromic stack according to claim 1 ; and
a second electrode layer.
18. The electrochromic device of claim 17 , wherein the second layer is positioned between an electrolyte layer and either the electrochromic layer or the counter electrode layer.
19. The electrochromic device of claim 18 , wherein the first electrode layer and the second electrode layer comprise a transparent conductive material.
20. The electrochromic device of claim 17 , wherein the ion conducting layer comprises lithium.
21. The electrochromic device of claim 17 , wherein the electrochromic layer has a coloring property different from that of the counter electrode layer.