Multi-Functional Smart Skin for High-Efficiency Energy-Saving Buildings.

Exploring scalable smart devices with broadband modulation, zero-energy input (without an external energy supply) controllable operation mode, and thermal insulation is of great significance for the building energy-saving. However, it remains a grand challenge to integrate such essential multi-functionality into one single device for affording extraordinary energy-saving effect. Here, we present a single-layer structured multi-functional smart "skin" (MSS) composed of thermal managing unit of high solar reflectance (Rsol = 93.8%) and low thermal conductivity (ĸ = 54 mW/m·K) and actuation unit of multi-responsive shape-memory effect. The ingenious integration of static thermal radiation property and dynamic shape changing capability enables the MSS superb solar modulating ability (ΔTsol = 88.1%). Selecting twenty-two cities with distinct climate conditions as the sample for analysis, the average energy-saving efficiency and carbon emission reduction of the MSS is 26.7% and 58.3 kg/m2. In addition, the MSS possesses zero-input controllable operation mode in all-season as assembling with a perovskite solar cell. This concept promotes the application of advanced functional devices in buildings, automobiles, and smart textiles.