A photoluminescent hydrogen-bonded biomass aerogel for sustainable radiative cooling

Passive radiant cooling is a potentially sustainable thermal management strategy amid escalating global climate change. However, petrochemical-derived cooling materials often face efficiency challenges owing to the absorption of sunlight. We present an intrinsic photoluminescent biomass aerogel, which has a visible light reflectance exceeding 100%, that yields a large cooling effect. We discovered that DNA and gelatin aggregation into an ordered layered aerogel achieves a solar-weighted reflectance of 104.0% in visible light regions through fluorescence and phosphorescence. The cooling effect can reduce ambient temperatures by 16.0°C under high solar irradiance. In addition, the aerogel, efficiently produced at scale through water-welding, displays high reparability, recyclability, and biodegradability, completing an environmentally conscious life cycle. This biomass photoluminescence material is another tool for designing next-generation sustainable cooling materials.