Efficient electrochromic performance of nanoparticulate WO sub(3) thin films

This report highlights the suitability of electrodeposited nanoparticulate-WO sub(3) (NP-WO sub(3)) electrodes for transmissive electrochromic devices (ECDs). The WO sub(3) electrodes in the form of thin films are composed of 10-20 nm nanoparticles. An electrochromic (EC) device of dimensions 5 4 cm super(2) fabricated using NP-WO sub(3) showed an Li insertion coefficient (x) of 0.43, which resulted in highest photopic transmittance modulation (88.51%), better Li-ion diffusion coefficient ( similar to 3.16 10 super(-9) cm super(2) s super(-1)), fast electrochromic response time (5.2 s for coloration and 3.7 for bleaching) and excellent coloration efficiency ( similar to 137 cm super(2) C super(-1)). On reduction of WO sub(3), the CIELAB 1931 2 degree color space coordinates show the transition from colorless to the deep blue state (Y= 97, a* = -1.93, b* = 0.46 and Y= 10, a* = 1.57, b* = -41.01) with steady decrease in relative luminance.