Temperature-Sensitive Colored Radiative Cooling Materials with Efficient Cooling Performance

Several daytime radiative cooling materials involving various structures and composed using multilayer thin films, polymers, and nanoparticles have been fabricated and studied. However, their surface is of white or some other monotonous color because of the requirement for most of the incident sunlight to be reflected. A temperature-sensitive colored radiative cooling (TCRC) material that provides efficient cooling while preserving the aesthetic properties of the surface has been developed. The TCRC material is manufactured as a bilayer structure for efferent cooling applied on a colored radiative cooling emitter. The bottom layer reflects as much light as possible using polyvinylidene fluoride and alumina particles, and the top layer uses a thermochromic color pigment to display color. The optical properties of the TCRC material, in response to temperature changes, are evaluated and its efficient cooling ability is confirmed. The temperature cooling is confirmed for TCRC emitters of yellow, magenta, and blue colors, using an outdoor temperature measurement system, and it is experimentally confirmed that the TCRC emitters provide more cooling (by 1.75, 2.67, and 4.31 °C, respectively) than conventional paint of the same color.