Porous NiMoO₄ Nanosheet Films and a Device with Ultralarge Optical Modulation for Electrochromic Energy-Storage Applications

Abstract

Reducing building energy consumption, improving aesthetics, and improving occupant privacy as well as comfort by dynamically adjusting solar radiation are important application areas for electrochromic (EC) smart windows. However, the current transition metal oxides still cannot meet the requirements of neutral coloration and large optical modulation. We report NiMoO 4 nanosheet films directly grown on fluorine-doped tin oxide glasses. The as-grown NiMoO 4 film not only achieves neutral coloration from transparent to dark brown but also shows an ultralarge optical modulation (86.8% at 480 nm) and excellent cycling stability (99.4% retention of maximum optical modulation after 1500 cycles). Meanwhile, an EC device demonstrating good EC performance was constructed. These results will greatly promote the research and development of binary transition metal oxides for both EC and energy-storage applications, and NiMoO 4 films may be an excellent candidate to replace NiO films as ion-storage layers in complementary EC devices with WO 3 films as EC layers.

Realizing Flexible Multicolored Electrochromism on Carbon Nanotubes through Thin-Film Interference

“…Although these examples successfully realize multicolored CNT fibers, the dynamic color-changing capabilities based on CNTs are still lacking. Electrochromism, as a typical technique that can alter the transparency or appearance color of materials/films by applying different voltages, offers broad prospects in smart windows and display devices. − In pursuit of versatile modulation, Wang et al used the Fabry−Perot cavity structure to fabricate electrochromic thin films with vivid structural colors . Based on this pioneering work, Li et al developed inverted-type devices by successively sputtering W and WO 3 onto the nylon-66-film as the upper electrochromic electrode, to avoid the impacted color quality as in the traditional sandwich-type devices .…”