Co-doped NiO nanoflake array films with enhanced electrochromic properties

Abstract

Co-doped NiO electrochromic nanoflake array films grown on FTO with antireflection ability have been synthesized by low temperature chemical bath deposition. Co doping has an influence on the growth and electrochromic properties of NiO nanoflake arrays. Noticeably, all the films show a very high transmittance at the bleached state in the region of visible light. Compared to the undoped NiO, the 1% Co-doped NiO nanoflake array film exhibits outstanding electrochromism, including large transmittance modulation (88.3%), high coloration efficiency (47.7 cm² C⁻¹), fast switching speed (3.4 s and 5.4 s), excellent reversibility and cycling durability at a wavelength of 550 nm. The enhanced electrochromic performances can be attributed to the synergetic effect contribution from low crystallization, oblique nanoflake array configuration and improved p-type conductivity by appropriate Co doping.