TY - JOUR
T1 - High-Performance Daytime Radiative Cooler and Near-Ideal Selective Emitter Enabled by Transparent Sapphire Substrate
AU - Chae, Dongwoo
AU - Son, Soomin
AU - Liu, Yuting
AU - Lim, Hangyu
AU - Lee, Heon
N1 - Funding Information:
This research was supported by Creative Materials Discovery Program through the National Research Foundation of Korea (NRF) funded by Ministry of Science and ICT (NRF‐2018M3D1A1058972) and Global Ph.D. Fellowship Program (NRF‐2019H1A2A1076622) by the National Research Foundation of Korea (NRF). This research was also supported by the Technology Innovation Program (20000887, Development of self‐healing impact resistant film coating material and process technology for rollable displays) funded By the Ministry of Trade, Industry & Energy (MOTIE, Korea).
PY - 2020/10/1
Y1 - 2020/10/1
N2 - Daytime radiative cooling serving as a method to pump heat from objects on Earth to cold outer space is an attractive cooling option that does not require any energy input. Among radiative cooler structures, the multilayer- or photonic-structured radiative cooler, composed of inorganic materials, remains one of the most complicated structures to fabricate. In this study, transparent sapphire-substrate-based radiative coolers comprising a simple structure and selective emitter-like optical characteristics are proposed. Utilizing the intrinsic optical properties of the sapphire substrate and adopting additional IR emissive layers, such as those composed of silicon nitride thin film or aluminum oxide nanoparticles, high-performance radiative coolers can be fabricated with a low mean absorptivity (3–4%) at 0.3–2.5 µm and a high mean emissivity of over 90% at 8–13 µm. Experiments show that the fabricated radiative coolers reach temperature drops of ≈10 °C in the daytime. From the theoretical calculations of radiative cooling performance, the sapphire-substrate-based radiative coolers demonstrate a net cooling power as high as 100 Wm−2.
AB - Daytime radiative cooling serving as a method to pump heat from objects on Earth to cold outer space is an attractive cooling option that does not require any energy input. Among radiative cooler structures, the multilayer- or photonic-structured radiative cooler, composed of inorganic materials, remains one of the most complicated structures to fabricate. In this study, transparent sapphire-substrate-based radiative coolers comprising a simple structure and selective emitter-like optical characteristics are proposed. Utilizing the intrinsic optical properties of the sapphire substrate and adopting additional IR emissive layers, such as those composed of silicon nitride thin film or aluminum oxide nanoparticles, high-performance radiative coolers can be fabricated with a low mean absorptivity (3–4%) at 0.3–2.5 µm and a high mean emissivity of over 90% at 8–13 µm. Experiments show that the fabricated radiative coolers reach temperature drops of ≈10 °C in the daytime. From the theoretical calculations of radiative cooling performance, the sapphire-substrate-based radiative coolers demonstrate a net cooling power as high as 100 Wm−2.
KW - atmospheric transparency window
KW - daytime radiative cooling
KW - selective emitters
KW - transparent sapphire substrates
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U2 - 10.1002/advs.202001577
DO - 10.1002/advs.202001577
M3 - Article
AN - SCOPUS:85089484298
VL - 7
JO - Advanced Science
JF - Advanced Science
SN - 2198-3844
IS - 19
M1 - 2001577
ER -