Transparent Wood Smart Windows: Polymer Electrochromic Devices Based on Poly(3,4‐Ethylenedioxythiophene):Poly(Styrene Sulfonate) Electrodes

Transparent wood composites, with their high strength and toughness, thermal insulation, and excellent transmissivity, offer a route to replace glass for diffusely transmitting windows. Here, conjugated‐polymer‐based electrochromic devices (ECDs) that switch on‐demand are demonstrated using transparent wood coated with poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a transparent conducting electrode. These ECDs exhibit a vibrant magenta‐to‐clear color change that results from a remarkably colorless bleached state. Furthermore, they require low energy and power inputs of 3 mWh m(−2) at 2 W m(−2) to switch due to a high coloration efficiency (590 cm(2) C(−1)) and low driving voltage (0.8 V). Each device component is processed with high‐throughput methods, which highlights the opportunity to apply this approach to fabricate mechanically robust, energy‐efficient smart windows on a large scale.