Fabrication of low defectivity electrochromic devices
View Patent ↗Prior electrochromic devices frequently suffer from high levels of defectivity. The defects may be manifest as pin holes or spots where the electrochromic transition is impaired. This is unacceptable for many applications such as electrochromic architectural glass. Improved electrochromic devices with low defectivity can be fabricated by depositing certain layered components of the electrochromic device in a single integrated deposition system. While these layers are being deposited and/or treated on a substrate, for example a glass window, the substrate never leaves a controlled ambient environment, for example a low pressure controlled atmosphere having very low levels of particles. These layers may be deposited using physical vapor deposition.
1. A method of fabricating an electrochromic device coating on a glass substrate in a deposition system comprising a plurality of deposition stations, the method comprising:
translating a substrate holder holding the glass substrate in a substantially vertical orientation through at least a lithium deposition station and two or more deposition stations of the plurality of deposition stations;
depositing a tungsten oxide based electrochromic material layer and a nickel oxide based counter electrode material layer on the glass substrate held in the substantially vertical orientation in the two or more deposition stations having two or more material sources;
depositing lithium metal onto either or both of the tungsten oxide based electrochromic material layer and the nickel oxide based counter electrode material layer of the electrochromic device coating on the glass substrate in the substantially vertical orientation in the lithium deposition station having a lithium metal sputter target configured to deposit the lithium metal, wherein the lithium metal sputter target is comprised of between about 90% and about 99% by weight lithium metal;
controlling, with a controller containing program instructions, the translation of the glass substrate through the plurality of the deposition stations and deposition of the tungsten oxide based electrochromic material layer, the nickel oxide based counter electrode material layer, and the lithium metal on the glass substrate; and
wherein lithium metal is deposited in an amount sufficient to compensate blind charge in the electrochromic device coating and an additional amount of 1.5 to 2.5 times, by mass.
2. The method of claim 1 , wherein the glass substrate is passed through the plurality of deposition stations under a controlled ambient environment without exposure to an external environment.
3. The method of claim 2 , wherein the controlled ambient environment is a pressure below atmospheric pressure or under vacuum.
4. The method of claim 1 , wherein depositing the tungsten oxide based electrochromic material layer and the nickel oxide based counter electrode material layer on the glass substrate held in the vertical orientation while in the two or more deposition stations having two or more material sources, comprises:
depositing the tungsten oxide based electrochromic material layer while at a first deposition station of the two or more deposition stations; and
depositing the nickel oxide based counter electrode material layer while at a second deposition station of the two or more depositions stations.
5. The method of claim 4 , wherein the two or more material sources comprise a first material source for depositing tungsten oxide and a second material source for depositing nickel oxide, nickel tungsten oxide, nickel vanadium oxide, nickel chromium oxide, nickel aluminum oxide, nickel magnesium oxide or nickel manganese oxide.
6. The method of claim 4 , further comprising depositing indium tin oxide on the electrochromic and counter electrode material layers at a third deposition station of the two or more deposition stations.
7. The method of claim 1 , further comprising supporting the substrate holder with a track as the substrate holder translates along the track through the plurality of deposition stations.
8. The method of claim 1 , wherein the nickel oxide based counter electrode material layer is doped with tantalum.
9. The method of claim 1 , wherein the glass substrate is tempered glass.
10. The method of claim 1 , wherein the glass substrate is untempered glass.