Ion implantation effects in polycrystalline WO3 thin films

Ion implantation is a possible technique to introduce electrochromically active dopants into fine-grained WO3 thin films. However, to be of use, we must be able to distinguish, and erase, effects due to collisional damage. Argon implants were performed in order to investigate damage effects. Pure damage was found to cause oxygen deficiency, leading to a broadband grey coloration. The formation of hydrogen bronzes (due to water vapor absorption), and of grain-grown material, are reported. Beam heating effects were found to be important due to the fine-grained nature of the material, and need to be suppressed in order for ion implantation to be a useful technique in this area.