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 . An apparatus for fabricating an electrochromic device, the apparatus comprising:
(a) an integrated deposition system for forming an electrochromic stack on a substrate, the 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;
(iii) a particle-removal device for removing particles from a surface of the substrate and/or the surface of the electrochromic stack before it is fully-formed;
(iv) a track configured to move the substrate from the first deposition station to the second deposition station; and
(v) a pallet hanging vertically from the track, configured to position the substrate in a vertical orientation; and
(b) a controller comprising:
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 and the layer of counter electrode material; and
program instructions for operating the particle-removal device to remove particles from the surface of the substrate and/or the surface of the electrochromic stack before it is fully-formed,
wherein at least one of the pallet and the first target or the second target is configured to move in two opposing linear directions relative to the other during deposition of the first material or the second material.
2 . The apparatus of claim 1 , wherein the program instructions comprise instructions for operating the particle-removal device to remove particles before the layer of electrochromic material is fully-formed.
3 . The apparatus of claim 1 , wherein the program instructions comprise instructions for operating the particle-removal device to remove particles before the counter electrode layer is fully formed.
4 . The apparatus of claim 1 , wherein operation of the particle-removal device reduces the number of visible short-related pinhole defects in the fabricated electrochromic device to a level no greater than about 0.005 per square centimeter.
5 . The apparatus of any of claim 1 , wherein the integrated deposition system further comprises:
(v) a third deposition station containing a third target comprising a third material, wherein the third deposition station is configured to deposit an electrode layer on the electrochromic stack when the substrate having the electrochromic stack is positioned in the third deposition station, and wherein the electrode layer comprises a transparent electronically conductive material.
6 . The apparatus of claim 1 , wherein at least one of the first target and the second target comprises a roller that rotates about an axis that is substantially parallel to a plane formed by the substrate, the roller having an outer surface configured to make contact with a surface of the substrate.