Amorphous Thermochromic VO2 Coatings Grown By APCVD At Low Temperatures

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

DOI: 10.5185/amlett.2015.5810

Publication Date (Web): Jul 12, 2015

Copyright © IAAM-VBRI Press

E-mail: dimitra@iesl.forth.gr

Abstract

Vanadium dioxide coatings were grown on SnO₂-precoated glass substrates by atmospheric pressure chemical vapor deposition using vanadyl (V) triisopropoxide at temperatures ≤ 450^oC. X-ray diffraction indicated the presence of metastable phase for the as-grown samples at 350 and 400^oC, while well-defined monoclinic vanadium dioxide phase was shown at 450^oC 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 450^oC. The best reversible behavior was at 64^oC with hysteresis width of 15^oC and a change in transmittance of 21 % for the as-grown coating at 450^oC. The significance of achieving thermochromic vanadium dioxide at temperatures ≤ 450^oC by a chemical procedure without post-treatment reduction and oxidant source is highlighted.

Keywords

APCVD, vanadium dioxide, monoclinic, thermochromicity.