Design and fabrication of MoSe2/WO3 thin films for the construction of electrochromic devices on indium tin oxide based glass and flexible substrates

Electrochromic devices (ECDs) have the ability to block the heat generated by sunlight, making them ideal for use in smart windows. Herein, we report the fabrication of ECDs using MoSe₂/WO₃ (MSW) as the electrochromic material, for smart windows applications. A solvothermal method was used for the synthesis of MoSe₂, while WO₃ was synthesized using a sol-gel approach. Subsequently, MoSe₂/WO₃ (MSW) hybrids with different wt% of MoSe₂ (0.05 wt%, 0.2 wt%, 0.5 wt%) were synthesized using an ultra-sonication approach. The physicochemical features of these MSW hybrids herein termed as MSW 0.05, MSW 0.2 and MSW 0.5, were investigated using X-ray diffraction (XRD), X-ray photon electron spectroscopic (XPS), scanning electron microscope (SEM), and EDS techniques and compared with pristine MoSe₂ and WO₃. The ECDs synthesized using MSW 0.05 showed increased coloration efficiency (62 cm^2 C-1) with an applied potential range of 0 to −1.5 V. Subsequently, the ECDs based on indium tin oxide (ITO) and MSW 0.05 demonstrated excellent electrochromic performance and stability for 10,000 cycles. The enhanced electrochromic performance of the MSW-based ECDs may be attributed to the conductive nature as well as the synergistic effects between MoSe₂ and WO₃ when compared to the WO₃-based ECDs. The synthesized MSW also showed promise as an electrochromic material in flexible ECDs for smart windows applications.