VO₂ particle-based intelligent metasurface with perfect infrared emission for the spacecraft thermal control

Abstract

Thermochromism film can automatically adjust its emittance without additional energy consumption, which shows great prospect in the application of spacecraft thermal control. However, it is still challenging to achieve a large infrared emittance at a high temperature and emittance tunability of the thermochromism film. In this work, we propose a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msub> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">V</mml:mi> <mml:mi mathvariant="normal">O</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> particle-based intelligent metasurface for spacecraft thermal control, which consists of a square lattice array of hollow spheroidal <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msub> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">V</mml:mi> <mml:mi mathvariant="normal">O</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> particles on Au substrate. The metasurface with a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msub> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">V</mml:mi> <mml:mi mathvariant="normal">O</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> particle having a large aspect ratio ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>∼</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>10</mml:mn> </mml:mrow> </mml:math> ) displays perfect emission throughout the entire mid-infrared spectral range. The emittance tunability can exceed 0.63 with total normal emittance of 0.85. The underlying mechanisms involved in the metasurface are attributed to particle-dependent scattering, by which the infrared emittance is dramatically enhanced for the metallic state and restricted for the dielectric state. In addition, the infrared emittance at a high temperature and emittance tunability of the metasurface remain large for incident angles up to 60°. To the best of our knowledge, this work proposes the first thermochromism film structure with perfect infrared emission, which could accelerate the development and practical application of the thermochromic film in the field of spacecraft.