Thermochromic VO2 based sandwich structure Ag/Al2O3/VO2 with low solar absorption and tunable emittance for spacecraft

The smart radiator device (SRD) with low solar absorption (αs) and large infrared emittance modulation (Δɛ) is desirable to a spacecraft thermal control system. In this work, the SRD was fabricated through depositing the Ag/Al2O3/VO2 triple-layer film on the Si substrate by magnetron sputtering. The properties of the SRD devices were optimized by tuning the thickness of the VO2 layer, and a fantastic SRD device was acquired, which showed low αs, high Δɛ, and intense high-temperature infrared emittance (ɛHT). For the device with a VO2 layer of 50 nm thickness, αs was as low as 29.7% and Δɛ reached 0.53 with ɛHT up to 0.87. The triple-layer film device shows great potential for applications in the spacecraft thermal control system.