Electrochromic performance of NiVxOy thin films deposited onto flexible PET/ITO substrates by reactive plasma sputtering for flexible electrochromic devices

An investigation was conducted on the electrochromic properties of plasma sputtered-nickel-vanadium oxide thin films on 40 Ω/□ flexible polyethylene terephthalate/indium tin oxide substrates. Metallic Ni_0.93V_0.07 target, sputtered by radio frequency power with argon gases and reacted with oxygen gases at room temperature (23 °C), was proven to provide extraordinary electrochromic performance. Cyclic voltammetry switching measurements found that only low driving voltages from − 1 V to 1 V were needed to provide reversible Li⁺ ion intercalation and deintercalation. The light modulation with up to 52% of transmittance variation, optical density change of 0.446 and color efficiency of 63.8 cm²/C at a wavelength of 550 nm was obtained for 200 cycles of Li⁺ intercalation and deintercalation in a 1 M LiClO₄-propylene carbonate electrolyte.