Sub-ambient daytime radiative cooling by silica-coated porous anodic aluminum oxide

Dasol Lee, Myeongcheol Go, Soomin Son, Minkyung Kim, Trevon Badloe, Heon Lee, Jin Kon Kim, Junsuk Rho

Research output: Contribution to journalArticlepeer-review

72 Citations (Scopus)


An energy-free daytime radiative cooler based on silica-coated porous anodic aluminum oxide is proposed, optimized, and experimentally realized. It is shown that a simple thin silica layer coating on porous anodic aluminum oxide can produce the spectral emissivity in the atmospheric window (8-13μm) required for sub-ambient cooling effect under direct sunlight. The final design, optimized using effective medium theory, exhibits high reflectance of 0.86 in the solar spectral region, and a substantial average emissivity of 0.96 in the atmospheric window. The fabricated centimeter-scale radiative cooler demonstrates a maximum cooling of 6.1 °C below ambient during the daytime. We believe that the proposed approach is a promising way to produce inexpensive and efficient radiative coolers.

Original languageEnglish
Article number105426
JournalNano Energy
Publication statusPublished - 2021 Jan


  • Anodic aluminum oxide
  • Atomic layer deposition
  • Daytime
  • Passive
  • Radiative cooling
  • Selective emitter

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)
  • Electrical and Electronic Engineering


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