Electrochromic properties of nanoporous Co3O4 thin films prepared by electrodeposition method

The nanoporous Co3O4 film was prepared by an electrodeposition method. The surface morphology and composition of the nanoporous Co3O4 film were characterised by scanning electron microscopy, energy-dispersive X-ray analysis and X-ray photoelectron spectroscopy. The electrochromic properties of Co3O4 film are investigated in an aqueous alkaline electrolyte (0.1 M KOH) by means of transmittance, cyclic voltammetry and chronoamperometry measurements. The as-prepared nanoporous Co3O4 film exhibits a noticeable electrochromism with reversible colour changes from pale yellow to dark blue and fast switching speed (3.0 and 2.6 s).