Summary: Commercially available electrochromic (EC) windows are based on solid-state devices in which WO3 and NiOx films commonly serve as the EC and counter electrode layers. respectively. These metal oxide layers are typically physically deposited under vacuum. a time- and capital-intensive process when using rigid substrates. https://www.lightemupsequences.com/quick-find-Our-Seasons-The-World-in-Winter-Spring-Summer-and-Autumn-best-save/