High Solar Energy Absorption and Human Body Radiation Reflection Janus Textile for Personal Thermal Management

A large of energy consumption is required for indoor and outdoor personal heating to ameliorate the comfortable and healthy conditions. Main personal thermal management strategy is to reflect mid-infrared human body radiation for human surface temperature (T-HS) regulation. We demonstrate a visible Janus light absorbent/reflective air-layer fabric (Janus A/R fabric) that can passively reflect radiative heating meanwhile can actively capture the solar energy. A series of azobenzene derivatives functionalized with alkyl tails are reported to co-harvest the solar and phase-change energy. The THS covered by Janus A/R fabric can be heated up to similar to 3.7 degrees C higher than that covered by air-layer fabric in cold environment (5 degrees C). Besides, integrating the thermo- and photo-chromic properties is capable of monitoring comfort THS and residue energy storage enthalpy, respectively. According to the colour monitors, intermittent irradiation approach is proposed to prolong comfortable-THS holding time for managing energy efficiently.