Particle removal during fabrication of electrochromic devices
Electrochromic devices are fabricated using a particle removal operation that reduces the occurrence of 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, the particle removal operation is not a lithiation operation. In some embodiments, the particle removal operation is performed at an intermediate stage during the deposition of either an electrochromic layer or a counter electrode layer.
1. A method of fabricating an electrochromic device, the method comprising:
providing a substrate having a first transparent electronically conductive layer comprising a first transparent electronically conductive material;
forming an electrochromic stack over the substrate having the first transparent electronically conductive layer, wherein forming the electrochromic stack comprises:
forming an electrochromic layer comprising an electrochromic material, and
forming a counter electrode layer comprising a counter electrode material; forming a second transparent electronically conductive layer over the electrochromic stack, the second transparent electronically conductive layer comprising a second transparent electronically conductive material,
wherein the first transparent electronically conductive layer and the second transparent electronically conductive layer sandwich the electrochromic stack; and
performing a particle-removal operation on a partially-formed electrochromic device to reduce the number of defects in the formed electrochromic device,
wherein the particle-removal operation is performed at any time before both the electrochromic layer and the counter electrode layer are fully-formed,
wherein the particle-removal operation is performed after the electrochromic layer is formed but before starting to form the counter electrode layer, and
wherein the particle-removal operation is performed after starting to form the electrochromic layer but before the electrohromic layer is fully formed.
2. The method of claim 1 , wherein the particle-removal operation reduces the number of visible short-related pinhole in the formed electrochromic device.
3. The method of claim 1 , wherein:
the first transparent electronically conductive material is selected from the group consisting of fluorinated tin oxide and indium-doped tin oxide; and
the second transparent electronically conductive material is indium-doped tin oxide.
4. The method of claim 1 , wherein the particle-removal operation comprises a technique selected from the group consisting of contact cleaning, irradiation, heat treatment, plasma treatment, contact with supercritical fluid, acoustic vibration, and contact with flowing ionized air.
5. The method of claim 1 , wherein the particle-removal operation comprises contact cleaning, and wherein the contact cleaning removes particles from a surface of the partially-formed electrochromic device by static electricity and/or adhesion.
6. The method of claim 5 , wherein the contact cleaning comprises contacting the surface of the partially-formed electrochromic device with one or more rollers, strips, or brushes.
7. The method of claim 1 , wherein the particle-removal operation comprises irradiating a surface of the partially-formed electrochromic device, and wherein the irradiation produces a volumetric expansion of the particles to be removed relative to surrounding portions of the partially-formed electrochromic device such that these particles are ejected from the surface of the partially-formed electrochromic device.
8. The method of claim 1 , wherein the particle-removal operation comprises contacting a surface of the partially-formed electrochromic device with a plasma.
9. The method of claim 8 :
wherein the plasma contact produces a build-up of electrical charge in the particles to be removed; and
wherein the particle-removal operation further comprises applying a voltage to an outer surface of the partially-formed electrochromic device such that the charged particles to be removed are ejected from the outer surface by repulsive electrostatic forces.
10. The method of claim 8 , wherein the plasma is a fluorine and/or oxygen plasma which etches away a film from the surface of the partially-formed electrochromic device such that particles are dislodged and/or removed with the film.
11. The method of claim 1 , wherein the particle-removal operation comprises a heat treatment of the partially-formed electrochromic device.
12. The method of claim 11 , wherein the heat treatment comprises heating the particles to be removed so as to cause the particles to volumetrically expand relative to surrounding portions of the partially-formed electrochromic device such that the particles are ejected from a surface of the partially-formed electrochromic device.
13. The method of claim 12 , wherein the heat-treatment comprises a heating technique selected from: irradiation with UV light, proximity to a resistive heating element, and exposure to a heated gas.
14. The method of claim 1 , wherein the particle-removal operation comprises dislodging or burning away particles from a surface of the partially-formed electrochromic device with a laser radiation.
15. The method of claim 14 , wherein the laser radiation is collimated into a flat beam which grazes the surface of the partially-formed electrochromic device.
16. The method of claim 15 , wherein the laser radiation is raster-scanned over the surface of the partially-formed electrochromic device.
17. The method of claim 1 , wherein the electrochromic material of the electrochromic layer is a cathodically-coloring electrochromic material, wherein the counter electrode material of the counter electrode layer is an anodically-coloring electrochromic material, and wherein the electrochromic layer is formed before forming the counter electrode layer.
18. The method of claim 17 , wherein the cathodically-coloring electrochromic material comprises a tungsten oxide, and the anodically-coloring electrochromic material comprises a nickel tungsten oxide.
19. The method of claim 18 , wherein forming the electrochromic stack further comprises forming an additional layer comprising tungsten oxide having a different tungsten to oxygen ratio than the tungsten oxide comprising the other cathodically-coloring electrochromic material.
20. The method of claim 1 , further comprising depositing lithium into the electrochromic stack.
21. The method of claim 1 , wherein the electrochromic stack is formed on the substrate while the substrate is oriented vertically.
22. The method of claim 1 , wherein the electrochromic stack is formed on the substrate while the substrate is oriented horizontally.
23. A method of fabricating an electrochromic device, the method comprising:
providing a substrate having a first transparent electronically conductive layer comprising a first transparent electronically conductive material;
forming an electrochromic stack over the substrate having the first transparent electronically conductive layer, wherein forming the electrochromic stack comprises:
forming an electrochromic layer comprising an electrochromic material, and
forming a counter electrode layer comprising a counter electrode material;
forming a second transparent electronically conductive layer over the electrochromic stack, the second transparent electronically conductive layer comprising a second transparent electronically conductive material,
wherein the first transparent electronically conductive layer and the second transparent electronically conductive layer sandwich the electrochromic stack; and
performing a particle-removal operation on a partially-formed electrochromic device to reduce the number of defects in the formed electrochromic device,
wherein the particle-removal operation is performed at any time before both the electrochromic layer and the counter electrode layer are fully-formed,
wherein the particle-removal operation is performed after the counter electrode layer is formed but before starting to form the electrochromic layer, and
wherein the particle-removal operation is performed after starting to form the counter electrode layer but before the counter electrode layer is fully formed.
24. The method of claim 23 , wherein the particle-removal operation reduces the number of visible short-related pinhole in the formed electrochromic device.
25. The method of claim 23 , wherein the particle-removal operation comprises a technique selected from the group consisting of contact cleaning, irradiation, heat treatment, plasma treatment, contact with supercritical fluid, acoustic vibration, and contact with flowing ionized air.
26. The method of claim 23 , wherein the particle-removal operation comprises contact cleaning, and wherein the contact cleaning removes particles from a surface of the partially-formed electrochromic device by static electricity and/or adhesion.
27. The method of claim 23 , wherein the particle-removal operation comprises irradiating a surface of the partially-formed electrochromic device, and wherein the irradiation produces a volumetric expansion of the particles to be removed relative to surrounding portions of the partially-formed electrochromic device such that these particles are ejected from the surface of the partially-formed electrochromic device.
28. The method of claim 23 , wherein the particle-removal operation comprises contacting a surface of the partially-formed electrochromic device with a plasma.
29. The method of claim 23 , wherein the particle-removal operation comprises a heat treatment of the partially-formed electrochromic device.
30. The method of claim 23 , wherein the particle-removal operation comprises dislodging or burning away particles from a surface of the partially-formed electrochromic device with a laser radiation.
31. A method of fabricating an electrochromic device, the method comprising:
providing a substrate having a first transparent electronically conductive layer comprising a first transparent electronically conductive material;
forming an electrochromic stack over the substrate having the first transparent electronically conductive layer, wherein forming the electrochromic stack comprises:
forming an electrochromic layer comprising an electrochromic material, and
forming a counter electrode layer comprising a counter electrode material;
forming a second transparent electronically conductive layer over the electrochromic stack, the second transparent electronically conductive layer comprising a second transparent electronically conductive material,
wherein the first transparent electronically conductive layer and the second transparent electronically conductive layer sandwich the electrochromic stack; and
performing a particle-removal operation on a partially-formed electrochromic device to reduce the number of defects in the formed electrochromic device,
wherein the particle-removal operation is performed at any time before both the electrochromic layer and the counter electrode layer are fully-formed,
wherein the electrochromic material of the electrochromic layer is a cathodically-coloring electrochromic material,
wherein the counter electrode material of the counter electrode layer is an anodically-coloring electrochromic material,
wherein the electrochromic layer is formed before forming the counter electrode layer, and
wherein the particle-removal operation is performed after starting to form the electrochromic layer but before the electrochromic layer is fully formed.
32. The method of claim 31 , wherein the cathodically-coloring electrochromic material comprises a tungsten oxide, and the anodically-coloring electrochromic material comprises a nickel tungsten oxide.
33. The method of claim 31 , wherein forming the electrochromic stack further comprises forming an additional layer comprising tungsten oxide having a different tungsten to oxygen ratio than the tungsten oxide comprising the other cathodically-coloring electrochromic material.
34. The method of claim 31 , wherein the particle-removal operation reduces the number of visible short-related pinhole in the formed electrochromic device.
35. The method of claim 31 , wherein the particle-removal operation comprises a technique selected from the group consisting of contact cleaning, irradiation, heat treatment, plasma treatment, contact with supercritical fluid, acoustic vibration, and contact with flowing ionized air.
36. The method of claim 31 , wherein the particle-removal operation comprises contact cleaning, and wherein the contact cleaning removes particles from a surface of the partially-formed electrochromic device by static electricity and/or adhesion.
37. The method of claim 31 , wherein the particle-removal operation comprises irradiating a surface of the partially-formed electrochromic device, and wherein the irradiation produces a volumetric expansion of the particles to be removed relative to surrounding portions of the partially-formed electrochromic device such that these particles are ejected from the surface of the partially-formed electrochromic device.
38. The method of claim 31 , wherein the particle-removal operation comprises contacting a surface of the partially-formed electrochromic device with a plasma.
39. The method of claim 31 , wherein the particle-removal operation comprises a heat treatment of the partially-formed electrochromic device.
40. The method of claim 31 , wherein the particle-removal operation comprises dislodging or burning away particles from a surface of the partially-formed electrochromic device with a laser radiation.