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Metasurfaces as Energy Valves for Sustainable Energy Management
Yoshiaki Nishijima1,2, Syunya Kimura1, Yu Takeshima1
1Department of Electrical and Computer Engineering, Graduate School of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan.
Micromachines
|October 27, 2022
Summary
This study demonstrates metal-insulator-metal metasurfaces for radiative cooling. These Indium-Tin-Oxide (ITO) based optical windows offer tunable light control for efficient thermal management in buildings.
Area of Science:
- Materials Science
- Nanotechnology
- Optics
Background:
- Metal-insulator-metal (MIM) metasurfaces offer tunable control over light absorption and transmission.
- Optical windows are crucial for managing thermal energy in buildings, impacting energy efficiency and comfort.
- Radiative cooling is an emerging technology for passive temperature regulation.
Purpose of the Study:
- To realize photo-thermal energy conversion for radiative cooling using MIM metasurfaces.
- To investigate the optical properties of Indium-Tin-Oxide (ITO) based MIM metasurfaces for window applications.
- To demonstrate a scalable fabrication method for practical window applications.
Main Methods:
- Fabrication of MIM metasurfaces using Indium-Tin-Oxide (ITO) and a calcium fluoride (CaF2) insulator.
- Patterning of the metasurface using low-resolution photolithography.
- Characterization of optical properties, including transparency in visible and absorption in mid-infrared wavelengths.
Main Results:
- Achieved high transparency of ITO in the visible spectrum and high absorption in the mid-infrared spectrum.
- Demonstrated the potential for photo-thermal energy conversion for radiative cooling.
- Showcased the scalability and simplification of the fabrication process.
Conclusions:
- MIM metasurfaces with ITO are suitable for optical window applications requiring selective light control.
- The developed metasurfaces can be used for efficient radiative cooling or heating, enhancing building energy performance.
- The low-resolution photolithography approach suggests a practical and scalable manufacturing route for these advanced windows.
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