Presentation Information
[2P44]Sweep rate dependence of injected and extracted charge of tungsten trioxide thin films created by reactive sputtering
*Shunsuke Miyazaki1, Takeo Nakano1, Suruz Mian2 (1. Department Of Science Technology, Seikei University, 2. School Of Engineering, Tokai University)
Tungsten trioxide (WO3) is an electrochromic (EC) material studied for functional windows. We have investigated thick WO3 films and found their superior light shielding, but the bleaching performance was inadequate. In this study, the voltage sweep rate in cyclic voltammetry (CV) was varied to improve this. 1000 nm thick WO3 films were analyzed using CV at sweep rates of 10, 20, and 40 mV/s. As the scan rate was increased, the injected charge decreased. This is because the faster voltage sweep provides less time for ions in electrolytes to diffuse deep into the film body, thereby limiting the overall charge injection process. The residual charge was also reduced at faster scan rates. The faster rates may hamper the ions from finding and being captured in stable trap sites, making them easier to extract.