High-performance ITO-free electrochromic films based on bi-functional stacked WO3/Ag/WO3 structures.

Stacked WO 3 /Ag/WO 3 (WAW) films were employed as both transparent electrodes and electrochromic materials. These nontoxic, low-cost WAW films that were prepared at room temperature exhibited not only low sheet resistance (12.2 Ω/□) and high transmittance (>80%) but also compelling electrochromic performance with high optical contrast (53%) at 650 nm, long-term cycling stability (3000 cycles), and short switching time (coloration time=11 s; bleaching time=10.5 s). The coloration efficiency of the WAW films was 136 cm 2 C –1 , which is higher than those of most electrochromic transition metal oxides. In addition, by utilizing such bi-functional films, the flexible electrochromic film with acceptable performance was obtained. [ABSTRACT FROM AUTHOR]