Sunlight-Induced Photo-Thermochromic Supramolecular Nanocomposite Hydrogel Film for Energy-Saving Smart Window

An ideal energy-saving smart window can not only provide a comfortable indoor temperature to avoid energy consumption of air-conditioning but also require low energy consumption for the material itself. However, current studies on smart windows either need extra consumption of electric and heat energy for switching or still face some challenges such as high indoor temperature and low durability. Herein, a supramolecular nanocomposite hydrogel film is prepared by integrating ethylene glycol-modified pillar[5]arene (EGP5) and antimony-tin oxide (ATO) nanoparticles. Owing to the thermo-responsiveness of EGP5 and plasmonic heating induced by near-infrared (NIR) absorption of ATO, the obtained film exhibits an outstanding photo-thermochromic effect, which results in excellent sunlight-induced solar modulation. Meanwhile, the film possesses high repeatability and durability based on the dynamicity and reversibility of EGP5-based host-guest interaction. Therefore, this supramolecular film is further applicable in the fabrication of smart windows for the investigation of regulating indoor temperature. The result demonstrates that the obtained smart window based on this supramolecular nanocomposite hydrogel film can preferentially trigger its sunlight-induced photo-thermochromic effect to achieve a cool indoor temperature for a more comfortable life.