VO2/Si-Al gel nanocomposite thermochromic smart foils: Largely enhanced luminous transmittance and solar modulation

VO2 nanoparticles with a dimension of approximately 20 nm were obtained by simple mechanical bead-milling method, which were well dispersed in transparent silica-alumina (Si-Al) gel matrix to form nanocomposites. The VO2/Si-Al gel thermochromic nanocomposite foils were fabricated with various VO2 solid contents and foil thickness. With 10% VO2 loading and 3 mu m foil thickness, high luminous transmittance (T-lum(20 degrees C) = 63.7% and T-lum(90 degrees C) = 54.4%), and large solar modulation ability (Delta T-sol = 12%) can be obtained which surpasses the best reported results (nanoporous films:T-lum(20 degrees C) = 43.3%, T-lum(90 degrees C)) = 39.9% and Delta T-sol = 14.1%). This current approach provided a simple and scalable preparation method with the best combined thermochromic performance. (C) 2013 Elsevier Inc. All rights reserved.