A Versatile Strategy for Concurrent Passive Daytime Radiative Cooling and Sustainable Energy Harvesting

Developing versatile systems that can concurrently achieve energy saving and energy generation is critical to accelerate carbon neutrality. However, challenges on designing highly effective, large scale, and multifunctional photonic film hinder the concurrent combination of passive daytime radiative cooling (PDRC) and utilization of sustainable clean energies. Herein, a versatile scalable photonic film (Ecoflex@h-BN) with washable property and excellent mechanical stability is developed by combining the excellent scattering efficiency of the hexagonal boron nitride (h-BN) nanoplates with the high infrared emissivity and ideal triboelectric negative property of the Ecoflex matrix. Strikingly, sufficiently high solar reflectance (0.92) and ideal emissivity (0.97) endow the Ecoflex@h-BN film with subambient cooling effect of ≈9.5 °C at midday during the continuous outdoor measurements. In addition, the PDRC Ecoflex@h-BN film-based triboelectric nanogenerator (PDRC-TENG) exhibits a maximum peak power density of 0.5 W m^-2 . By reasonable structure design, the PDRC-TENG accomplishes effective wind energy harvesting and can successfully drive the electronic device. Meanwhile, an on-skin PDRC-TENG is fabricated to harvest human motion energy and monitor moving states. This research provides a novel design of a multifunctional PDRC photonic film, and offers a versatile strategy to realize concurrent PDRC and sustainable energies harvesting.