Solution-Deposited Solid-State Electrochromic Windows

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. Herein we report a facile solution deposition method for producing amorphous WO3 and NiOx layers that prove to be effective materials for a solid-state EC device. The full device containing these solution-processed layers demonstrates performance metrics that meet or exceed the benchmark set by devices containing physically deposited layers of the same compositions. The superior EC performance measured for our devices is attributed to the amorphous nature of the NiOx produced by the solution-based photodeposition method, which yields a more effective ion storage counter electrode relative to the crystalline NiOx layers that are more widely used. This versatile method yields a distinctive approach for constructing EC windows.