Electricity-Efficient On-Demand Photothermal Activation for Tunable Thermochromic Windows

Thermochromic (TC) windows with passively controlled sunlight regulation have demonstrated significant building energy conservations. Realizing the active control of the TC window can expand its popularity while remaining an intractable challenge. Herein, a low-power-dissipative strategy that endows TC windows with an actively tunable transmittance is presented through the electro-induced tunable photothermal conversions (ETPCs). Through diverse transmittance variations at different voltages, sunlight can be selectively transformed to the desired photothermal temperatures. After integration with the TC hydrogel, the thermochromism can be optionally accelerated or turned off in diverse weather conditions. The fabricated smart window can realize a high optical modulation (ΔT500 nm = 85.13%) to lower the indoor temperature by 26.2 °C in a low-energy consumption (lower than 10.5 μW·cm–2). Compared with normal windows, the as-fabricated smart window can cut off 20.1% of the building energy consumption, demonstrating huge potential to combat global climate change.