Radiative cooling is an emerging cooling technology that can passively release heat to the environment. To obtain a subambient cooling effect during the daytime, chemically engineered structural materials are widely explored to simultaneously reject sunlight and preserve strong thermal emission. However, many previously reported fabrication processes involve hazardous chemicals, which can hinder a material's ability to be mass produced. In order to eliminate the hazardous chemicals used in the fabrication of previous works, this article reports a white polydimethylsiloxane (PDMS) sponge fabricated by a sustainable process using microsugar templates. By substituting the chemicals for sugar, the manufacturing procedure produces zero toxic waste and can also be endlessly recycled via methods widely used in the sugar industry. The obtained porous PDMS exhibits strong visible scattering and thermal emission, resulting in an efficient temperature reduction of 4.6 °C and cooling power of 43 W m⁻² under direct solar irradiation. In addition, due to the air‐filled voids within the PDMS sponge, its thermal conductivity remains low at 0.06 W (m K)⁻¹. This unique combination of radiative cooling and thermal insulation properties can efficiently suppress the heat exchange with the solar‐heated rooftop or the environment, representing a promising future for new energy‐efficient building envelope material.

As a sustainable technology, radiative cooling has received considerable attention due to its potential in energy sustainability. Unlike conventional cooling techniques, radiative cooling does not consume electricity during its operation and is therefore particularly attractive in reducing the energy demand for cooling and addressing global warming by reducing carbon emissions. The general principle requires a radiative cooler to be thermally emissive to dissipate heat via thermal radiation. During the daytime, the cooler needs to minimize the solar heating effect to ensure subambient temperatures. Guided by these criteria, researchers have developed various materials with engineered optical, thermal, and mechanical features. In this review, we will first explore the fundamentals of heat transfer in radiative cooling processes. Subsequently, we will summarize the state-of-the-art progress on material synthesis and system designs. Building upon those recently developed features, we will review how this technology has been implemented in practical applications, ranging from thermal management of buildings, semiconductor cooling, personal comfort design, and atmospheric water harvesting. Finally, we will conclude this review by identifying and discussing some of the remaining challenges requiring future research and development.

Radiative cooling presents a method for reducing the operational temperature of solar panels without additional energy consumption. However, its applicability to PV modules has been limited by the thermal properties of existing materials. To overcome these challenges, we introduce a V-shaped design that enhances cooling in vertical PV modules by effectively harnessing thermal radiation from both the front and rear sides, resulting in a substantial temperature reduction of 10.6°C under 1 sun illumination in controlled laboratory conditions. Field tests conducted in warm and humid conditions, specifically in Thuwal, Saudi Arabia, demonstrate a remarkable 15% increase in efficiency while maintaining an operating temperature 0.2°C lower than that of conventional horizontal PV modules, corresponding to a significant 16.8% increase in power output. Our innovative V-shaped design offers a promising thermal strategy suitable for diverse climates, contributing to improved performance and reduced module temperatures, thereby supporting the global pursuit of carbon neutrality.