Reversible Electrochemical Silver Deposition over Large Areas for Smart Windows and Information Display

Silver based reversible electrochromic (EC) devices which can be used for smart windows and information display are analysed to examine the factors that determine switching time, color, and scale-up. These devices demonstrate multiple colors: silver, black, magenta, yellow and dark cyan blue with switching time as low as 5 seconds. The usage of redox mediators, applied bias, in enhancing the kinetics of the color transformation while being constrained by the electrochemical window of the DMSO solvent was examined. By a judicious combination of these factors, fabrication of large-area electrochromic devices up to 77 cm² operating at −3.0 V for formation of mirror-like reflective state (∼100% reflectance) in less than 15 seconds; and reverse switching to transparency at 0.5 V in less than 30 seconds have been realised. Devices capable of transforming into different patterns are also demonstrated with similar switching performance.