For sustainable energy-efficient applications, through advanced optical engineering, our novel passive daytime radiative cooling (PDRC) materials exhibit high average reflectivity or transparency (>95%) in the solar wavelength region and high average emissivity (>95%) in the atmosphere window wavelength region. We anticipate that these PDRC materials will effectively mitigate the urban heat island effect, improve the low-grade waste heat recovery and reduce carbon dioxide emissions.

1. PDRC metamaterials achieve superior cooling power of 112 W/m2 under sunlight and provide temperature declines of 12.7 °C and 17 °C for buildings and vehicles, respectively. 
2. PDRC films offer excellent cooling performance for optoelectronic devices, with TSRC films achieving a temperature drop of 14 °C for solar panels.
3. Our PDRC/TEG system generates the highest thermoelectric power among recently developed systems, reaching 225.3 mW/m2 during the daytime and 412.3 mW/m2 at night.

The PDRC metamaterials can provide the great potential to accelerate the pace of net-zero emissions to limit global warming. Also, PDRC films provide a facile, eco-friendly cooling solution to dissipate trapped heat in optoelectronic devices, such as solar panels. The attractive power generation ability of the PDRC/TEG system suggests its great potential in low-grade waste heat recovery and environmental energy harvesting by consistently generating power in both the daytime and nighttime.