Radiative cooling is a passive cooling technology that acts by reflecting sunlight and
emitting radiation in the sky window. Although highly desirable, full daytime sub-ambient
radiative cooling in commercial-like single-layer particle-matrix paints has not been
achieved. Here, we demonstrate full daytime sub-ambient radiative cooling in CaCO 3-
acrylic paint by using large band gap CaCO 3 fillers, a high particle concentration of 60%,
and a broad size distribution. Our paint shows a high solar reflectance of 95.5% and a high …

We demonstrate remarkable full-daytime subambient cooling performance with CaCO3 and
BaSO4 nanoparticle paints. These fillers have a high electron band gap for low solar
absorptance and phonon resonance or polymer absorption in the sky window for high sky
window emissivity. With an appropriate particle size and a broad particle size distribution,
the BaSO4 nanoparticle film reaches an ultrahigh solar reflectance of 97.6% and a high sky
window emissivity of 0.96. During field tests, the BaSO4 film stays more than 4.5° C below …