Colored and paintable bilayer coatings with high solar-infrared reflectance for efficient cooling

Yijun Chen, Jyotirmoy Mandal, Wenxi Li, Ajani Smith-Washington, Cheng Chia Tsai, Wenlong Huang, Sajan Shrestha, Nanfang Yu, Ray P.S. Han, Anyuan Cao, Yuan Yang

Research output: Contribution to journalArticlepeer-review

185 Scopus citations

Abstract

Solar reflective and thermally emissive surfaces offer a sustainable way to cool objects under sunlight. However, white or silvery reflectance of these surfaces does not satisfy the need for color. Here, we present a paintable bilayer coating that simultaneously achieves color and radiative cooling. The bilayer comprises a thin, visible-absorptive layer atop a nonabsorptive, solar-scattering underlayer. The top layer absorbs appropriate visible wavelengths to show specific colors, while the underlayer maximizes the reflection of near-to-short wavelength infrared (NSWIR) light to reduce solar heating. Consequently, the bilayer attains higher NSWIR reflectance (by 0.1 to 0.51) compared with commercial paint monolayers of the same color and stays cooler by as much as 3.0° to 15.6°C under strong sunlight. High NSWIR reflectance of 0.89 is realized in the blue bilayer. The performances show that the bilayer paint design can achieve both color and efficient radiative cooling in a simple, inexpensive, and scalable manner.

Original languageEnglish (US)
Article numberaaz5413
JournalScience Advances
Volume6
Issue number17
DOIs
StatePublished - Apr 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General

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