Fast-switching electrochromic smart windows based on NiO-nanorods counter electrode

Abstract

Not only do the outstanding electrochromic devices provide a fast switching response, but they can also block light and heat to reduce energy consumption in buildings. Herein, we fabricated an outstanding WO 3 /NiO nanorods-based electrochromic device consisting of a working electrode of 1D WO 3 nanorods/ITO/glass substrate and a counter electrode of 1D NiO nanorods/ITO/glass substrate. The 1D NiO nanorods with a large surface area act as an ion storage layer, which can offer a huge number of electrons to form small polarons and the localized surface plasmon resonance on the 1D WO 3 nanorods. The high small polaron content causes strong lattice distortion, which helps the Li + ions easily diffuse into the 1D WO 3 nanorods and gives the 1D WO 3 /NiO nanorods-based electrochromic device excellent electrochromic characteristics. The electrochromic characteristics include high optical transmittance difference (~61, ~89 %), high coloration efficiency (174, 386 cm 2 /C) and fast coloration/bleaching switching times (~2.05/~0.74 s, ~0.85/~1.0 s) at the wavelengths of 680 and 1000 nm, respectively. These characteristics make the WO 3 /NiO nanorods-based electrochromic device a very promising smart window candidate for lighting control and energy-saving applications. • WO 3 /NiO based electrochromic device with 1D WO 3 and NiO nanorods as electrodes. • Polaronic and LSPR effects cause the Vis and NIR absorption. • 1D NiO nanorods play a key role in the improvement of electrochromic performance. • Fast switching time, high optical transmittance difference and long cycle life.