VO2-based active tunable emittance thermochromic flexible coatings

This contribution reports, for what we believe is the first time, on VO2-based thin-film coatings on flexible Al substrates exhibiting a tunable positive emittance-switching Delta epsilon = (epsilon(H)-epsilon(L))> 0. More precisely, a layered stack of a-Si V H/SiO2/VO2 on flexible Al sheets presents minimum and maximum values of emissivity of about 0.18 and 0.57 at 40 degrees Cand 83 degrees C, respectively, and hence allows an emittance-switching Delta epsilon of 0.39 and a relative variation Delta epsilon/epsilon(A) of similar to 217%. Such variations fit with the potential applications of such coatings as smart radiation devices in small satellites and spacecraft. (C) 2020 Optical Society of America