Preparation of CoS2/WO3 thin films for the construction of electrochromic devices

Abstract

In this study, we report CoS2/WO3 (CSW) composites as electrochromic materials for applications in smart windows. A hydrothermal approach was used to obtain CoS2, whereas WO3 was prepared using the sol-gel method. We prepared the CSW composites with various weight ratios of CoS2 (0.2, 0.5, and 2.0 wt%) by ultrasonication dispersion. The physical and chemical properties of the CSW composites (CSW 0.2, CSW 0.5, and CSW 2.0) were examined via X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Additionally, the WO3 and CSW based ECDs were fabricated using indium-tin oxide (ITO) substrate. The CSW 0.5 based ECDs exhibited excellent coloration efficiency of 64.5 cm2C-1 and an optical contrast of 73.31%. The enhanced coloration efficiency and optical contrast may be attributed to synergistic interactions between CoS2 and WO3. The ECDs also exhibited good stability up to 10,000 cycles.