Building‐Tailored Hierarchical Electrochromism with Optimized Control Strategies

Abstract Electrochromic smart windows struggle with a material‐application disconnect. So, a building‐centric paradigm is established to bridge this gap through dual breakthroughs: multi‐band hierarchical material and control strategy. An electrochromic device (ECD) based on Prussian blue (PB) with multi‐band hierarchical modulation is demonstrated, integrating Fe 4 [Fe(CN) 6 ] 3 and Nb 18 W 16 O 93 film electrodes, where hierarchical regulation relies on potassium ion shuttling (rocking‐chair mechanism) and cation‐anion co‐intercalation dynamics. It enables four spectral customization states: transparent heating (S1), zero‐energy bright heating (S2), daylight‐preserving bright cooling (S3), and maximum‐blocking dark cooling (S4). An Electrochromic window (ECW) constructed with such ECD, when coupled with optional intelligent control strategies, transforms these capabilities into unprecedented energy savings. The load‐responsive strategy focuses on building internal demands, leverages the zero‐energy S2 state for >75% of summer operation, achieving 25.4% cooling energy reduction versus normal windows. The climate‐adaptive strategy, centered on external environmental constraints and guided by “location‐specific adjustment”, reveals >50% performance disparities between control parameters, enabling location‐optimized operation such as 56.9% summer energy savings even in cold Helsinki. By embedding tunable spectral control into the building energy management logic, material, and control strategy innovations have jointly paved a scalable path from laboratory innovation to building application.