A selectively-absorbing material includes a silicone polymer and transition-metal oxide nanoparticles dispersed therein. Each of the transition-metal oxide nanoparticles includes manganese. A solar receiver includes (i) a metal substrate including an etched surface having a microroughness between 0.05 micrometers and two micrometers; (ii) a polymer matrix disposed on the etched surface; and (iii) transition-metal oxide nanoparticles dispersed within the polymer matrix. A method for producing transition-metal oxide nanoparticles includes recrystallizing a plurality of two-element nanoparticles at a temperature between 300 and 700 C. The plurality of two-element nanoparticles includes at least two of (i) copper oxide nanoparticles, (ii) manganese oxide nanoparticles, and (iii) iron oxide nanoparticles. A method for fabricating a selective-absorber includes etching a top surface of a metal substrate; depositing a polymer-matrix composite on the etched top surface; and interdiffusing the polymer-matrix composite and the metal substrate. The polymer-matrix composite includes transition-metal oxide nanoparticles dispersed therein.

The radiative cooling device includes an infrared radiative layer A that radiates infrared light IR from a radiative surface H, a light reflective layer B disposed on a side opposite to the radiative surface H with respect to the infrared radiative layer A, and a protective layer D disposed between the infrared radiative layer A and the light reflective layer B. The infrared radiative layer A is a resin material layer J having a thickness adjusted so as to emit a heat radiation energy greater than an absorbed solar energy in a wavelength range from 8 m to 14 m. The light reflective layer B contains silver or a silver alloy, and the protective layer D is formed from a polyolefin based resin with a thickness of 300 nm or more and 40 m or less or an ethylene terephthalate resin with a thickness of 17 m or more and 40 m or less.

The radiative cooling device includes an infrared radiative layer A that radiates infrared light IR from a radiative surface H, a light reflective layer B disposed on a side opposite to the radiative surface H with respect to the infrared radiative layer A, and a protective layer D disposed between the infrared radiative layer A and the light reflective layer B. The infrared radiative layer A is a resin material layer J having a thickness adjusted so as to emit a heat radiation energy greater than an absorbed solar energy in a wavelength range from 8 m to 14 m. The light reflective layer B contains silver or a silver alloy, and the protective layer D is formed from a polyolefin based resin with a thickness of 300 nm or more and 40 m or less or an ethylene terephthalate resin with a thickness of 17 m or more and 40 m or less.

Provided are an infrared absorber having extremely low reflectivity in the wavelength band of infrared rays, a method for manufacturing the same, a black-body radiation device, and a radiative cooling device. Provided is an infrared absorber 10 provided with: an absorption layer 11 comprising carbon black and a resin; and, on the absorption layer 11, a surface layer 12 that comprises a resin including essentially no pigment and that has an optical confinement structure 13 in which a plurality of minute projections are formed on the surface thereof, the hemispherical total reflectivity of the infrared absorber 10 in infrared wavelengths of 5-15 m being 0.2% or less. Further provided are a method for manufacturing the infrared absorber, a black-body radiation device, and a radiative cooling device.

Provided are an infrared absorber having extremely low reflectivity in the wavelength band of infrared rays, a method for manufacturing the same, a black-body radiation device, and a radiative cooling device. Provided is an infrared absorber 10 provided with: an absorption layer 11 comprising carbon black and a resin; and, on the absorption layer 11, a surface layer 12 that comprises a resin including essentially no pigment and that has an optical confinement structure 13 in which a plurality of minute projections are formed on the surface thereof, the hemispherical total reflectivity of the infrared absorber 10 in infrared wavelengths of 5-15 m being 0.2% or less. Further provided are a method for manufacturing the infrared absorber, a black-body radiation device, and a radiative cooling device.