Journal of Advanced Materials and Technologies

Journal of Advanced Materials and Technologies

On the substrate wettability of a tungsten sol for the preparation of WO3 thin films

Authors
Mohamad Ali Bahrevar
Yadolah Ganjkhanlou
Mahmood Kazemzad
Houshang Azizi
Materials and Energy Research Center, Semiconductor dept, Karaj, Iran
10.30501/jamt.2635.70283
Abstract
In this work, WO3 thin films have been deposited on optical glass and transparent conducting oxide substrates using aqueous and organic sols by means of dip coating followed by post annealing at 400 oC. The wetting of applied substrates by the prepared sol has been simply studied by observation and photography. The prepared thin films were also studied by various techniques including scanning electron microscopy, X-ray diffraction, and cyclic voltammetry in H2SO4 solution. The results showed that aqueous sols showed undesired wetting while aqueous-alcoholic sols could splendidly wet both glass and TCO substrates. However, the use of ethyl alcohol resulted in the degradation of the films during the drying process whereas this problem could be overcome by the introduction of heavy alcohols.Aqueous-alcoholic sols prepared from Lauryl Alcohol andperoxytungstic acid which was previously synthesized from sodium tungstate precursors were optimized as the dipping sol. Results showed that the presence of Lauryl alcohol reduces the size of the crystallites and grains in the prepared thin films. The monoclinic phase of WO3was transformed to triclinic phase by the addition of Lauryl alcohol to the prepared sol. The cyclic voltametery analyses also verified the improved electrochromic properties of the prepared layers in the presence of Lauryl alcohol.
Keywords
Tungsten oxide
Sol-Gel
wetting
thin films
  1. Granqvist, C.G, Handbook of inorganic materials; Elsevier Science, Oxford, 1995.
  2. Deb, S. K., Opportunities and Challenges in Science and Technology of WO3 for Electrochromic and Related Applications,Solar Energy Mater. Solar Cells, 2008, 92, 245.
  3. Guo, Y., Quan, X., Lu, N., Zhao, H., Chen, S., High Photocatalytic Capability of Self-Assembled Nanoporous WO3 with Preferential Orientation of (002) Planes, Sci. Technol., 2007, 41, 4422.
  4. Nimittrakoolchai, O., Supothina, S., High-Yield Precipitation Synthesis of Tungsten Oxide Platelet Particle and its Ethylene Gas-Sensing Characteristic, Chem. Phys., 2008, 112, 270.
  5. Wang, W., Pang, Y. Hodgson, S. N. B., preparation, Preparation,Characterization and Electrochromic Property of Mesostructured Tungsten Oxide Films Via a Surfactant Templated Sol-Gel Process from Tungstic Acid, Sol Gel Sci. Technol.,2010, 54
  6. Bathe, S. R., Patil, P. S., Electrochromic Characteristics of Pulsed Spray Pyrolyzed Polycrystalline WO3 Thin Films,Smart Mater. Struct., 2009, 18
  7. Santato, C., Ulmann, M., Àugustynski, J., Photoelectrochemical Properties of Nanostructured Tungsten Trioxide Films,J Phys Chem B, 2001, 105, 936.
  8. Santato, C., Odziemkowski, M., Ulmann, M., Augustynski, J., Crystallographically Oriented Mesoporous WO3 Films: Synthesis, Characterization, and Applications, Am. Chem. Soc., 2001, 123, 10639.
  9. Mackenzie, J. D., Applications of the Sol-Gel Process, Non Cryst. Solids, 1988, 100, 162.
  10. Bica, E., Mureşan, L. E., Barbu-Tudoran, L., Indrea, E., Popescu, I. C., opovici, E., Studies on WO3 Thin Films Prepared by Dip-Coating Method,Studia Universitatis Babes-Bolyai Chemia, 2009, 3, 15.
  11. Wang, W., Pang, Y., Hodgson, S. N. B., On Key Factors for the Fabrication of Mesoporous Tungsten Oxide Films from Tungstic Acid, Sol Gel Sci. Technol., 2011, 58, 135.
  12. Deepa, M., Saxena, T. K., Singh, D. P., Sood, K. N., Agnihotry, S. A., Spin Coated Versus Dip Coated Electrochromic Tungsten Oxide Films: Structure, Morphology, Optical and Electrochemical Properties, Acta, 2006, 51, 1974. 
  13. Deepa, M., Singh, P., Sharma, S. N., Agnihotry, S. A., Effect of Humidity on Structure and Electrochromic Properties of Sol-Gel-Derived Tungsten Oxide Films,Solar Energy Mater. Solar Cells,2006, 90, 2665.
  14. Fang, Y., Sun, X., Cao, H., Influence of PEG Additive and Annealing Temperature on Structural and Electrochromic Properties of Sol-Gel Derived WO3 Films, Sol Gel Sci. Technol., 2011, 59, 145.
  15. Srivastava, A. K., Agnihotry, S. A., Deepa, M., Sol-Gel Derived Tungsten Oxide Films with Pseudocubic Triclinic Nanorods and Nanoparticles,Thin Solid Films, 2006, 515, 1419.
  16. Breedon, M., Spizzirri, P., Taylor, M., Plessis, J. D., McCulloch, D., Zhu, J., Yu, L., Hu, Z., Rix, C., Wlodarski, W., Kalantar-zadeh, K., Synthesis of Nanostructured Tungsten Oxide Thin Films: A Simple, Controllable, Inexpensive, Aqueous Sol-Gel Method, Growth Des., 2010, 10, 430.
  17. Livage, J., Ganguli, D., Sol-Gel Electrochromic Coatings and Devices: A Review,Solar Energy Mater. Solar Cells,2001, 68, 365.
  18. Yang, B., Zhang, Y., Drabarek, E., Barnes, P. R. F., Luca, V., Enhanced photoelectrochemical Activity of Sol-Gel Tungsten Trioxide Films through Textural Control, Mater., 2007, 19, 5664.
Journal of Advanced Materials and Technologies
Volume 3, Issue 4
Winter 2014
Pages 63-69

  • Receive Date 04 May 2014
  • Revise Date 22 February 2015
  • Accept Date 22 February 2015