Polyaniline/WO2.86 composite film for dual-band electrochromic smart windows

Dual-band electrochromic (EC) materials have gained significant attention in contemporary research due to their unique capacity to selectively manage near-infrared (NIR) and visible (VIS) light spectra. Nevertheless, the endeavor to design and develop dual-band EC films poses a formidable challenge, primarily stemming from the limited availability of suitable high-performance materials. In our study, we have successfully synthesized polyaniline (PANI)/WO_2.86 dual-band EC films, which exhibit reversible color transitions across four distinct hues (light blue, yellow-green, dark blue, and dark green). These films were fabricated using PANI nanorods (NRs) and WO_2.86 nanowires (NWs) containing oxygen vacancy defects as the active EC components. Notably, the P-W5 film demonstrated good dual-band modulation capabilities in both VIS and NIR regions. Its swift switching dynamics (coloring/bleaching times of 10 s/13.5 s), high coloring efficacy (65.3 cm²C^-1), and robust cycling stability (retaining 72.2 % of its capacity after 3000 cycles) can be attributed to the electrode material's 3D porous nanostructure and efficient Li⁺ ion diffusion. Additionally, the EC smart window prototype, incorporating PANI/WO_2.86 dual-band EC materials, exhibited remarkable thermal insulation properties, resulting in a temperature reduction of 14.4 °C within a model room compared to traditional double-glazed windows. This investigation presents a viable strategy for the design of dual-band EC materials and paves the way for their application in smart windows and intelligent displays.