Periodic trapezoidal VO2-Ge multilayer absorber for dynamic radiative cooling
Optics Express
|July 19, 2020
Summary
A novel vanadium dioxide-germanium multilayer absorber system enables dynamic radiative cooling by leveraging VO2
Area of Science:
- Materials Science
- Optics
- Thermodynamics
Background:
- Dynamic radiative cooling is increasingly important for thermal management.
- Existing systems often struggle with daytime solar irradiation and efficient heat dissipation.
Purpose of the Study:
- To propose and develop a dynamic radiative cooling system.
- To investigate the performance of a vanadium dioxide-germanium multilayer absorber (VGMA).
Main Methods:
- Designed a cooling system with a filter and a periodic trapezoidal VGMA.
- Exploited the phase transition properties of vanadium dioxide (VO2) for tunable spectral absorptance.
- Analyzed spectral absorptance as a function of layer number and incident angle.
Main Results:
- Achieved near-zero absorptance (0.3-2.5 μm) and tunable high/low absorptance (8-13 μm) in VO2.
- Identified magnetic resonance and surface plasmon polariton resonance in the insulating phase.
- Observed broadband high absorptivity via slow-light waveguide mode in the metallic phase.
- Demonstrated angle-insensitivity of the absorber.
- Reported a 4x increase in net cooling power upon phase transition to metallic VO2.
Conclusions:
- The developed VGMA system effectively achieves dynamic radiative cooling.
- The system's performance is tunable via VO2 phase transition, offering significant cooling potential.
- This work advances the field of dynamic radiative cooling technologies.
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