Dynamically Tunable Thermochromic Smart Windows for Building Energy Conservation

Thermochromic smart windows (TSWs) exist passive regulation for building energy conservation, which are challenging to be artificially manipulated. The electrothermal stratagem has been explored for introducing the “active control” function. However, it is limited by the excess electricity consumption. Here, we fabricate a TSW with electricity-efficient tunable functions by combining transparent photothermal and electrothermal technologies. The “active control” function is escorted by a transparent electrode with electrical conductivity and photothermal efficiency from layer-by-layer (LBL) assembled silver nanowires and MXene nanosheets. It shows high transparent sunlight conversion to lower the inherent temperature threshold for thermochromism and retrenches the electricity consumption. Under the synergistic effect of photothermal and electrothermal processes, the TSWs show remarkable solar modulation (Δ T sol = 61.8%) during both summer and winter. The LBL-assembly technique is simple to manipulate, which provides an energetic paradigm for the commercial applications of TSWs while enabling superb annual building energy conservation.