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A Thermal Radiation Modulation Platform by Emissivity Engineering with Graded Metal-Insulator Transition
Kechao Tang1,2, Xi Wang1, Kaichen Dong1
1Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
Advanced Materials (Deerfield Beach, Fla.)
|July 24, 2020
Summary
Researchers developed a novel material that manipulates infrared radiation by engineering its integrated emissivity (εint). This breakthrough enables temperature-independent thermal radiation, paving the way for advanced infrared camouflage.
Area of Science:
- Materials Science
- Thermodynamics
- Optics
Background:
- Thermal radiation follows the Stefan-Boltzmann law, proportional to absolute temperature to the fourth power (T4).
- Integrated emissivity (εint) typically shows minimal temperature sensitivity (|dεint /dT| ≈ 10-4 °C-1), limiting radiative heat control.
- The T4 dependence of radiance restricts precise thermal regulation.
Purpose of the Study:
- To engineer a material platform for arbitrary control of integrated emissivity (εint) near room temperature.
- To demonstrate a method for counteracting the T4 dependence of thermal radiation.
- To enable the development of advanced infrared camouflage technologies.
Main Methods:
- Fabrication of tungsten-doped vanadium dioxide thin films with a graded tungsten fraction.
- Engineering the integrated emissivity (εint) to exhibit significant temperature dependence (|dεint /dT| ≈ 8 × 10-3 °C-1).
- Programming εint to vary inversely with T4 to achieve temperature-independent thermal radiance.
Main Results:
- Demonstrated a material where integrated emissivity (εint) can be engineered for arbitrary temperature dependence.
- Achieved precise counteraction of the Stefan-Boltzmann T4 law, resulting in temperature-independent thermal radiance.
- Successfully created a surface with engineered emissivity for advanced thermal radiation manipulation.
Conclusions:
- A novel material platform allows unprecedented control over infrared radiation by engineering temperature-dependent emissivity.
- Temperature-independent thermal radiance was achieved, enabling power-free, stable infrared camouflage.
- The graded tungsten-doped vanadium dioxide structure offers a unique approach to manipulating thermal signatures.
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