Flower-like nickel oxide micro/nanostructures: synthesis and enhanced electrochromic properties

Abstract

Nickel oxide (NiO) micro/nanoflowers were synthesized by hydrothermal treatment followed by calcination. The concentration of potassium persulfate (K₂S₂O₈) plays a significant role in the formation of the NiO micro/nanoflowers. The NiO film annealed at 300 °C for 1.5 h exhibits fast coloration/bleaching response (1.3 s for coloration and 3.2 s for bleaching) and high coloration efficiency (49.8 cm² C⁻¹) due to the flower-like micro/nanostructures, showing a potential application in fast-response smart windows.