Investigation of Thermochromic and Optical Properties of VO₂ Thin Films Derived from Thermal Reduction of V₂O₅ Deposited on Graphene

Patrick Muvaka^1, , Waweru Mugo¹, Richard Ongeri¹ and James Ngaruiya¹

¹Jomo Kenyatta University of Agriculture and Technology

Cite this paper:
Patrick Muvaka, Waweru Mugo, Richard Ongeri and James Ngaruiya. Investigation of Thermochromic and Optical Properties of VO₂ Thin Films Derived from Thermal Reduction of V₂O₅ Deposited on Graphene. Journal of Materials Physics and Chemistry. 2022; 10(1):23-26. doi: 10.12691/jmpc-10-1-4

Abstract

Vanadium dioxide has been of interest for thermochromic smart windows to control the near infrared radiation (NIR), but suffers limitations due to high transition temperature, low luminous transmittance and low solar modulation ability. In this paper, we report on low switching temperature and improved balance between luminous transmittance and solar modulation ability of VO₂ derived from thermal reduction of sol-gel deposited vanadium pentoxide (V₂O₅) on graphene. Thermal reduction of vanadium pentoxide (V₂O₅) was done in an innert atmosphere of flowing argon gas under normal atmospheric pressure. The optical properties of thermally reduced films were investigated using UV-VIS-NIR spectrophotometer while transition temperature was determined by measuring sheet resistance as a function of temperature. The films revealed semiconductor to metal transition after investigation. An analysis of transmittance showed an improved NIR switching efficiency of 46.86% for VO₂ on graphene compared to 41.79 for VO₂ on bare glass. Resistance drops corresponding to 2 and 3 orders of magnitude for VO₂/glass and VO₂/graphene /glass respectively were realized. VO₂ film on graphene/glass substrate had a transition temperature of 55.4 ^oC lower than 61.2^oC for VO₂ on bare glass substrate. The low Semiconductor-Metal Transition (SMT) temperature and the enhanced trade-off between luminous transmittance and solar modulation ability are noted to emanate from the increased crystallinity and nano-scale crystallites of VO₂ films enhanced by graphene matrix. The results reveal that graphene enhanced solar modulation ability and lowered transition temperature through structural ordering and nanoscale reduction of VO₂ crystallites.

Keywords:
Vanadium dioxide graphene transition temperature smart window near infrared radiation

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References:

[1]	Wu J., Huang W.X., Shi Q.W., Cai J.H., Zhao D., Zhang Y.B. and Yan J.Z., (2013). Effect of annealing temperature on thermochromic properties of vanadium dioxide thin films deposited by organic sol-gel method, Applied surface science. 268: 556-560.
[2]	Morin F.J., (1959). Oxides which show a metal-to-insulator transition at the knee temperature, physical review letters, 318 (5857): 1750-1753.
[3]	Babulanam F.S, Erickson T., Niklasson G. and Granqvist C., (1987). Thermochromic VO2 films for energy efficient windiows, Solar energy materials, 83(3): 347-363.
[4]	Granqvist C., Green S., Niklasson G.A., Mlyaka N.R., Kraemer S.V., and Georen P., (2010), Advances in chromogenic materials and devices, Thin solid films, 518(11): 3046-3053.
[5]	Li S. (2013) VO2-based thermochromic and Nanothermochromic materials for energy-efficient windows,Dissertation from the faculty of science and technology-uppsala university Sweden, 1095: 143.
[6]	Gao Y., Cao C., Dai L., Luo H., Kanehira M., Ding Y. and Wang Z, (2012). Phase and shape controlled VO2 nanostructure by antimony doping, energy environmental science, 5:8708-8715.
[7]	Parkin I.P and Manning T.D., (2006). Intelligent thermochromic windows, journal of chemical education, 83(3): 393
[8]	Goodenough J.B, (1971), The two components of the crystallographic transition in VO2, Journal of solid state chemistry, 3(4): 490-500.
[9]	Kim H., Kim Y., Kim T.Y., Jang A.R., Jeong H.Y., Han S.H., Yoon D.H., and Shin H.S., (2013), Enhanced optical response of hybridized VO2/graphene films, Electronic supplementary material for nanoscale, 21: 463-816.
[10]	Miao L., Chen R., Zhou J., Liu C., Peng Y., Gao J, Sun L. and Tanemura S, (2016). Depressed haze and enhanced solar modulation capability for VO2-based composite films with distinct size effects, Journal of Royal society of chemistry, 6: 90813-90823.
[11]	El-Nahass M.M., Soliman H.S. and El-Denglawey A., (2016). Absorption edge shift, optical conductivity and energy loss function of nano thermal evaporated N-type anatase TiO2 films. Journal of applied physics 122 (8): 775.
[12]	Miller M.J and Wang J. (2015), Influence of grain size on transition temperature of thermochromic VO2, Journal of applied physics, 117 (034307).
[13]	Sahana M.B., Darmaprakash M.S. and Shivashankar S.A., (2002). Microstructure and properties of VO2 thin films deposited by MOCVD from vanadyl acetylacetonate, Journal of material chemistry, 12: 333-338.
[14]	Kivaisi R.T. and Samiji M., (1999). Optical and electrical properties of vanadium dioxide films prepared under optimized rf sputtering conditions, Solar energy materials and solar cells, 57: 141-157.
[15]	Ambonisye S., Samiji M.E. and Mlyuka NR, (2015). Luminous transmittance and phase transition temperature of VO2: CE thin films prepared by DC magnetron sputtering, Tanzania journal of science, 6: 1078-1081.
[16]	Gao Y., Wang S., 2Luo H., Cao C., Liu Y., Chen Z. and Kanehira M., (2012). Enhanced chemical stability of VO2 nanoparticles by the formation of SiO2/VO2 core/shell structures and the application to transparent and flexible VO2-based composite foils with excellent thermochromic properties for solar heat control, Energy environmental science, 5: 6104-6110.
[17]	Zhou H., Li S., Xin Y., Cao X., Bao S. and Jin ping, (2015). Electron transfer induced thermochromism in a VO-Graphene-Ge hetero-structure, Journal of materials chemistry, 3: 5089-5097.
[18]	Lüth H., Solid surfaces, Interfaces and Thin films, Springer, Berlin, 2010.
[19]	Laad M.S, Craco L and Hartmann Mueller, (2006). Metallizing the mott insulator TiOCl by electron doping, Condensed matter physics, 73: 195120.