Nanoparticulate films of WO3 and MoO3 composites for enhancing UV light electrochromic transmittance variation and energy storage applications

Abstract

Green technologies for the manufacture of optical shutters retain a sustainable development. In this work, the electro-exploding wires and spray coating technologies are employed to deposit nanoparticulate (WO3)1-x(MoO3)x composite films. MoO3 NPs are introduced to enhance electrochromic (EC) transmittance variation of violet and UV light with wavelengths ranging from 330 to 450 nm. Measurements of EC performances of (WO3)1-x(MoO3)x composite films in a potentiostat are carried out to discern beneficial from MoO3 addition. It is observed that the diffusion coefficient and the charge density increase with an increment of MoO3 concentration. The coloration efficiency at 430 nm raises apparently whereas that at 633 nm does not show a significant variation with increasing MoO3 concentrations. In addition, the EC device with ∼12.5% of MoO3 introduced reveals a much higher optical modulation at 430 nm. From the measurements of galvanostatic charge-discharge curves of EC films in the potentiostat, the areal capacitances of 12.9 and 14.0 mF/cm2 are estimated for pure and ∼12.5% MoO3 introduced WO3 EC films. The EC batteries are demonstrated and the enlarged energy storage capability with an addition of MoO3 is observed. The simple introduction of MoO3 into WO3 nanoparticulate films compensates drawbacks of WO3 films and enhances EC performances and energy storage capabilities.