Radiative cooling passively removes heat from objects via emission of thermal radiation to cold space. Suitable radiative cooling materials absorb infrared light while they avoid solar heating by either reflecting or transmitting solar radiation, depending on the application. Here, we demonstrate a reflective radiative cooler and a transparent radiative cooler solely based on cellulose derivatives manufactured via electrospinning and casting, respectively. By modifying the microstructure of cellulose materials, we control the solar light interaction from highly reflective (> 90%, porous structure) to highly transparent (≈ 90%, homogenous structure). Both cellulose materials show high thermal emissivity and minimal solar absorption, making them suitable for daytime radiative cooling. Used as coatings on silicon samples exposed to sun light at daytime, the reflective and transparent cellulose coolers could passively reduce sample temperatures by up to 15 °C and 5 °C, respectively.

辐射冷却通过向冷空间发射热辐射来被动地从物体中去除热量。合适的辐射冷却材料吸收红外光，同时根据应用通过反射或传输太阳辐射来避免太阳加热。在这里，我们展示了分别基于通过静电纺丝和浇铸制造的纤维素衍生物的反射辐射冷却器和透明辐射冷却器。通过修改纤维素材料的微观结构，我们控制了太阳光相互作用，从高反射（> 90%，多孔结构）到高度透明（≈ 90%，均质结构）。两种纤维素材料都显示出高热发射率和最小的太阳能吸收，使其适用于白天的辐射冷却。