Template synthesis of NiO ultrathin nanosheets using polystyrene nanospheres and their electrochromic properties

Abstract

Ultrathin nickel oxide (NiO) nanosheets with a thickness of ∼10 nm were synthesized by a template method. NiO film was prepared by spin-coating polystyrene@Ni₂CO₃(OH)₂ nanostructures on indium tin oxide (ITO) coated glass and a calcination process. Electrochromic properties of NiO thin film were investigated in an aqueous alkaline electrolyte (1.0 mol L⁻¹ KOH) by means of transmittance and cyclic voltammetry (CV) measurement. The NiO film annealed at 300 °C exhibits noticeable electrochromism with a transmittance modulation of 40.1%, fast coloration and bleaching responses (5.4 and 3.6 s) and high coloration efficiency (43.5 cm² C⁻¹).