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 device comprising:
a substrate;
a first electrode layer disposed on the substrate;
an electrochromic stack comprising an electrochromic layer of electrochromic material and a counter electrode layer of counter electrode material;
a second electrode layer disposed on the electrochromic stack; and
a defect-mitigating insulating layer (DMIL) comprising a substantially transparent and electronically insulating first material disposed between the first electrode layer and the electrochromic stack; wherein:
the first material includes a plurality of voids or gaps that are at least partially filled by a second material from a polishing compound used to polish the DMIL.
2. The electrochromic device of claim 1 , wherein the first material comprises a first electronically insulating material and the second material comprises a second, different, electronically insulating material.
3. The electrochromic device of claim 2 , wherein the second material comprises particles from the polishing compound.
4. The electrochromic device of claim 3 , wherein the particles include alumina.
5. The electrochromic device of claim 1 , wherein the polishing compound includes one or both of aluminum oxide and cerium oxide.
6. The electrochromic device of claim 1 , wherein the first material comprises a metal oxide, a metal nitride, a metal carbide, a metal oxynitride, or a metal oxycarbide.
7. The electrochromic device of claim 6 , wherein the first material comprises a metal oxide selected from the group consisting of aluminum oxide, titanium oxide, tantalum oxide, cerium oxide, zinc oxide, tin oxide, silicon aluminum oxide, tungsten oxide, nickel tungsten oxide, and oxidized indium tin oxide.
8. The electrochromic device of claim 7 , wherein the first material is titanium oxide and the second material is alumina.
9. The electrochromic device of claim 6 , wherein the first material comprises a metal nitride selected from the group consisting of titanium nitride, aluminum nitride, silicon nitride, tantalum nitride, and tungsten nitride.
10. The electrochromic layer of claim 6 , wherein the first material comprises a metal carbide selected from the group consisting of titanium carbide, aluminum carbide, silicon carbide, tantalum carbide, and tungsten carbide.
11. A method of fabricating an electrochromic device, the method comprising:
forming an electrochromic stack on a first electrode layer disposed on a substrate, wherein the electrochromic stack comprises an electrochromic layer of electrochromic material and a counter electrode layer of counter electrode material;
forming a defect-mitigating insulating layer (DMIL) within, beneath, or on the electrochromic stack, wherein the DMIL comprises a substantially transparent and electronically insulating first material and forming the DMIL includes polishing the DMIL with a polishing compound; and
forming a second electrode layer over the electrochromic stack; wherein:
the first material includes a plurality of voids or gaps that are at least partially filled by a second material from the polishing compound.
12. The method of claim 11 , wherein the first material comprises a first electronically insulating material and the second material comprises a second, different, electronically insulating material.
13. The method of claim 12 , wherein the second material comprises particles from the polishing compound.
14. The method of claim 13 , wherein the particles include alumina.
15. The method of claim 11 , wherein the polishing compound includes one or both of aluminum oxide and cerium oxide disposed in a carrier so as to form a polishing slurry.
16. The method of claim 1 , wherein the first material comprises a metal oxide, a metal nitride, a metal carbide, a metal oxynitride, or a metal oxycarbide.
17. The method of claim 16 , wherein the first material is titanium oxide and the second material is alumina.
18. An electrochromic device comprising:
a substrate;
a first electrode layer disposed on the substrate;
an electrochromic stack comprising an electrochromic layer of electrochromic material and a counter electrode layer of counter electrode material, wherein the first electrode layer is between the substrate and the electrochromic stack;
a second electrode layer disposed on the electrochromic stack such that the electrochromic stack is disposed between the first electrode layer and the second electrode layer; and
a defect-mitigating insulating layer (DMIL) comprising a substantially transparent and electronically insulating first material, disposed between the first electrode layer and the electrochromic stack; wherein:
the first material includes a plurality of voids or gaps that are at least partially filled by a second material from a polishing compound used to polish the DMIL.
19. The electrochromic device of claim 18 , wherein the first material comprises a first electronically insulating material and the second material comprises a second, different, electronically insulating material.
20. The electrochromic device of claim 18 , wherein the polishing compound includes one or both of aluminum oxide and cerium oxide.
21. The electrochromic device of claim 18 , wherein the second material comprises particles from the polishing compound.
22. A method of fabricating an electrochromic device, the method comprising:
(a) receiving a substrate in a sputter deposition apparatus, wherein the substrate includes a first electrode layer and a defect-mitigating insulating layer (DMIL) comprising a substantially transparent and electronically insulating first material formed thereon, the first electrode layer is disposed between the substrate and the DMIL, the first electrode layer comprises a first transparent electronically conductive material, the DMIL having been polished with a polishing compound, and the first material includes a plurality of voids or gaps that are at least partially filled by a second material from the polishing compound;
(b) forming an electrochromic stack on the substrate, wherein the electrochromic stack comprises an electrochromic layer of electrochromic material and a counter electrode layer of counter electrode material; and
(c) forming a second electrode layer over the electrochromic stack, the second electrode layer comprising a second transparent electronically conductive material.
23. The method of claim 22 , wherein the first material comprises a first electronically insulating material and the second material comprises a second, different, electronically insulating material.
24. The electrochromic device of claim 22 , wherein the second material comprises particles from the polishing compound.
25. An apparatus for fabricating an electrochromic device, comprising:
(a) an integrated deposition system comprising:
(i) a first deposition station containing a first target comprising a first material for depositing a layer of an electrochromic material on a substrate when the substrate is positioned in the first deposition station,
(ii) a second deposition station containing a second target comprising a second material for depositing a layer of a counter electrode material on the substrate when the substrate is positioned in the second deposition station, and
(iii) a third deposition station configured to deposit a defect-mitigating insulating layer (DMIL) comprising a substantially transparent and electronically insulating first material, the DMIL being polished with a polishing compound, and the first material including a plurality of voids or gaps that are at least partially filled by a second material from the polishing compound; and
(b) a controller containing program instructions for passing the substrate through the first and second deposition stations in a manner that sequentially deposits a stack on the substrate, the stack comprising the layer of electrochromic material, the layer of counter electrode material, and the defect-mitigating insulating layer.