All-season multiband electrochromic smart windows for dynamically compatible regulation of solar and thermal radiation

The adaptive regulation of solar and thermal radiation through windows plays a pivotal role in building energy conservation. However, most state-of-the-art electrochromic smart windows can only modulate solar radiation; achieving dynamic and compatible regulation of both solar and thermal radiation within a single integrated window remains highly desirable yet challenging. Herein, we present an all-season multiband electrochromic smart window that integrates dual-band electrochromism with dynamic radiative cooling through an electrode engineering design. The window not only controls the visible light and near-infrared independently, but also modulates the solar transmittance and mid-infrared thermal emittance dynamically and compatibly through bright heating, bright cooling, and dark cooling states, thereby significantly reducing the building energy consumption. Furthermore, the window exhibits impressive electrochromic performance, including high multiband optical contrast from visible to mid-infrared (ΔT_700nm = 52.8% and Δε_8–14μm = 0.53, where ΔT_700nm and Δε_8–14μm represent optical contrasts at 700 nm and 8–14 μm, respectively), fast switching speed (4.6/2.6 s for coloration/bleaching), and outstanding cycle stability (negligible degradation after 10,000 cycles). Notably, the window displays remarkable temperature control performance with 11.5 °C lower than the low-emissivity glass. Simulations further confirm the higher energy-saving performance of the window than the low-emissivity glass in most climatic zones around the world. Our work provides a feasible strategy for designing all-season multiband electrochromic smart windows for energy-efficient buildings.