Amorphous Thermochromic VO2 Coatings Grown By APCVD At Low Temperatures
Dimitra Vernardou1*, Dimitris Louloudakis1, 2, Emmanouil Spanakis3, Nikolaos Katsarakis1, 4, 5, Emmanouil Koudoumas1, 5
1Center of Materials Technology and Photonics, School of Applied Technology, Technological Educational Institute of Crete, Heraklion, Crete, 710 04, Greece
2Department of Physics, University of Crete Heraklion, Crete, 711 00, Greece
3Department of Materials Science and Technology, University of Crete, Heraklion, 711 00, Crete, Greece
4Institute of Electronic Structure and Laser, Foundation for Research & Technology-Hellas, P.O. Box 1527, Vassilika Vouton, Heraklion, Crete, 711 10, Greece
5Electrical Engineering Department, Technological Educational Institute of Crete, Heraklion, Crete, 710 04, Greece
Adv. Mater. Lett., 2015, 6 (7), pp 660-663
Publication Date (Web): Jul 12, 2015
Copyright © 2019 VBRI Press
Vanadium dioxide coatings were grown on SnO2-precoated glass substrates by atmospheric pressure chemical vapor deposition using vanadyl (V) triisopropoxide at temperatures ≤ 450oC. X-ray diffraction indicated the presence of metastable phase for the as-grown samples at 350 and 400oC, while well-defined monoclinic vanadium dioxide phase was shown at 450oC as derived by Raman spectroscopy. The different phases of vanadium dioxide affected the coating’s morphology presenting long grains with irregular size and shape turning to flattened structures composed with grains of uniform dimensions as the temperature increased from 350 to 450oC. The best reversible behavior was at 64oC with hysteresis width of 15oC and a change in transmittance of 21 % for the as-grown coating at 450oC. The significance of achieving thermochromic vanadium dioxide at temperatures ≤ 450oC by a chemical procedure without post-treatment reduction and oxidant source is highlighted.
APCVD, vanadium dioxide, monoclinic, thermochromicity.