Tungsten oxide–cellulose nanocrystal composite films for electrochromic applications

Abstract

© The Authors. Composite films of tungsten oxide and CNCs are prepared through a sol-gel method and their electrochromic (EC) properties investigated. After mixing CNC gel into a tungsten oxide precursor solution, indium-tinoxide- coated glass substrates are dipped into the composite solution and subsequently annealed at 170°C. The composite films consisted of CNCs dispersed in the tungsten oxide matrix. The resulting nanocomposite was found to be amorphous, exhibiting a high transmission modulation and very good cycling stability. After having tested a range of compositions, a film of WO3 with 10% CNC was found to be the most uniform and showed good EC performance. These results bode well for further work on CNC-EC composites for specific applications, especially when used on flexible substrates.