Hydrogel smart windows

Smart windows are a promising way to modulate solar light transmittance, which is crucial for energy saving buildings. Current challenges focus on designing hydrogel materials that have multi-functionality, low cost, a fabrication process suitable for mass production, and durability. Here in this review, we provide an overview of the recent progress in hydrogel-based smart windows in different categories (thermo-, electro- and humidity-stimuli), focusing on the functional hydrogel material selectivity, working mechanisms and device design. The challenges and opportunities of hydrogel smart windows are discussed in the perspective section.