Research progress on optical structure and processing strategy of radiative-cooling wood

Radiative cooling reduces the surface or internal temperature of buildings through passive radiative heat dissipation, decreases energy consumption, and is an important means of achieving green buildings and carbon neutrality today. The existing radiative cooling materials mainly consist of photonic crystal structures, multi-scale porous structures, multi-layer thin film structures, and micro-nano textured surfaces, utilising their high solar reflectance and high infrared emissivity to achieve radiative cooling. Wood naturally possesses porous structures along with high solar emissivity and reflectance, making it highly promising for utilisation in the field of radiative cooling. This paper starts from the principles of radiative cooling, detailing the interaction between the multi-scale structures of natural wood and light, as well as the chemical structures and optical properties of cellulose, hemicellulose, and lignin. It reviews research progress in recent years on cell wall processing strategies for radiative cooling wood, enhancement strategies for photonic crystal materials, multi-spectral design control strategies, and multifunctional integration strategies. Additionally, it looks forward to addressing urgent issues and future development directions for wood composite materials in the field of radiative cooling.