IR electrochromic WO3 thin films: From optimization to devices

Abstract This paper reports enhanced electrochromic properties in the infrared region, so-called IR, and in particular, in the middle wavelength (MW: 3–5 μm) and long wavelength (LW: 8–12 μm), of radio frequency sputtered (RFS) WO 3 thin films, thanks to a careful optimization of the deposition conditions, namely the duration of deposition ( 3 thin films cycled in H 3 PO 4 liquid electrolyte, are reported. Such performances correspond to a variation in emissivity of at least 40% as required for military applications. Finally, coupling both modelling and experimental approaches, first trends on the incorporation of the WO 3 single layer in full electrochromic devices (ECDs) are discussed considering mainly an all-solid-state device configuration.