Synthesis and characterization of MoS2/WO3 nanocomposite for electrochromic device application

In this work, WO3 nanopowder was synthesized by an acidic co-precipitation method using sodium tungstate, nitric acid, and distilled water as precursors, while molybdenum disulfide (MoS2)/tungsten trioxide (WO3) nanocomposite was prepared by exfoliation of MoS2 in WO3 at different concentrations of MoS2 on WO3. All materials were analysed for their structural characteristics using X-ray diffraction (XRD) spectra. The XRD spectra confirm the formation of prepared samples. The morphology of the nanocomposites was investigated by field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). FESEM and HRTEM show that the addition of 2% MoS2 has an insignificant effect on the morphology of WO3 but when the MoS2 concentration is increased to 4%, the particles' edges agglomerate and combine to create layered nanostructures that resemble flowers and join together to form a sphere. The electrochemical performance of all prepared samples was investigated using charge/discharge, chronoamperometry, and cyclic voltammetry. The electrochemical test results show that the electrochemical properties increase after the addition of MoS2 in WO3 due to the large active surface area. At +/- 1.5 V operating voltage, The electrochromic and optical properties of the prepared thin films were investigated using UV/Vis spectroscopy. The MSW2 nanocomposite exhibits the highest optical transmittance of 84% in the bleached state and 25% in the coloured state with a colouration efficiency of 67 cm(2)C(-1). The MSW2 nanocomposite retains a 97% colouration efficiency after 100 cycles. The electrochromic studies show that MoS2/WO3 nanocomposites exhibit good results at low MoS2 contents (ie, up to 2%). When the proportion of MoS2 in WO3 is increased (above 2%), the electrochromic performance decreases due to the deterioration of the transmittance (T%) of the nanocomposite.

Automated summary

In this work, WO3 nanopowder was synthesized, and MoS2/WO3 nanocomposite was prepared. The addition of MoS2 in WO3 led to the formation of layered nanostructures and change in morphology. The electrochemical properties of the nanocomposites improved due to the large active surface area. The nanocomposites also exhibited good optical properties at low MoS2 contents.