Using Intrinsic Intracrystalline Tunnels for Near‐Infrared and Visible‐Light Selective Electrochromic Modulation

Dual‐band electrochromic composite materials are of utmost importance in advancing the electrochromic field toward achieving the ideal smart window with independent control over visible and near‐infrared (NIR) radiation. However, such composites usually need deliberate architecting of their mesoscale structure (e.g., via block copolymer‐templating method) to make the electrolyte contact with both NIR and visible‐light modulating components. Herein, instead of arduously making exterior pores, the intrinsic structural tunnels are utilized directly in electrochromic materials to facilitate the accommodation and transportation of insertion ions, which permit the infiltration of the electrolyte to be in contact with both visible (Prussian blue) and NIR‐light modulating components (nonstoichiometric tungsten oxide). Such simple‐fabricated composite materials exhibit excellent dual‐band electrochromic performance with an unprecedented dynamic optical range for modulation of visible and NIR light, up to 71.2% at 633 nm and 64.8% at 1600 nm, respectively.