Photonic Metafabric with Biomimetic Triangular Light Track for Passive Radiative Cooling

Integrating passive radiative cooling techniques with wearable fabrics provides a zero-energy strategy for preventing people from heat stress and reducing cooling demand. However, developing wearable passive radiative cooling fabrics with ideal optical characteristics, wearability, and scalability has consistently presented a challenge. Here, we developed a metafabric with high sunlight reflectivity (88.07%) according to the design of an individual photonic structure, which demonstrates total internal reflection with the tailored triangular light track. A skin simulator covered by metafabric exhibits a temperature drop of 7.17 °C in the daytime compared with regular polyester fabric in an outdoor cooling test. Consequently, it was theoretically proven to exert a substantial influence on achieving a significant cooling demand reduction of 52.69–185.79 W·m⁻². These characteristics, coupled with structural stability, air-moisture permeability, sufficient wearability, and scalability, allowed the metafabric to provide a solution for introducing zero-energy passive radiative cooling technique into human body cooling.