A novel electrochromic device with high optical switching speed Original Research Article

An electrochromic device (ECD) with the configuration of ITO/WO3/propylene carbonate (PC)+LiClO4+HNO3/NiO/ITO has been successfully developed. The developed ECD possesses the advantage of high optical switching speed (coloring transition time 22 s, bleaching transition time 1 s) for the application of back mirror. The coloration process of WO3 was dramatically improved by addition of HNO3 in the liquid PC+LiClO4 electrolyte. The added HNO3 generates larger quantities of H+ ions which shuttle the WO3 film fast because of its quite light mass increasing the color center to speedup the coloration process. Hence the developed method is available for improving optical switching speed of the ECD.