Ultrabroadband Photonic Structures To Achieve High-Performance Daytime Radiative Cooling

• Published in: Nano letters Vol. 13; no. 4; pp. 1457 - 1461
• Main Authors: Rephaeli, Eden, Raman, Aaswath, Fan, Shanhui
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 10.04.2013
• Subjects: Ambient temperature; Atmosphere; Atmospherics; Condensed matter: structure, mechanical and thermal properties; Cooling; Daytime; Exact sciences and technology; Heat exchange; Hot Temperature; Metals - chemistry; Nanostructures - chemistry; Outdoor; Photonics; Photons; Physics; Solar power generation; Sunlight; Thermal properties of condensed matter; Thermal properties of small particles, nanocrystals, nanotubes; phonon-polariton; Radiative cooling; selective emission; thermal radiation; broadband solar mirror; Thermal conductivity; Transparency; Mirrors; Heat treatments
• ISSN: 1530-6984; 1530-6992; 1530-6992
• DOI: 10.1021/nl4004283

If properly designed, terrestrial structures can passively cool themselves through radiative emission of heat to outer space. For the first time, we present a metal-dielectric photonic structure capable of radiative cooling in daytime outdoor conditions. The structure behaves as a broadband mirror for solar light, while simultaneously emitting strongly in the mid-IR within the atmospheric transparency window, achieving a net cooling power in excess of 100 W/m2 at ambient temperature. This cooling persists in the presence of significant convective/conductive heat exchange and nonideal atmospheric conditions.