Effect of precursors on the microstructural, optical, electrical and electrochromic properties of WO3 nanocrystalline thin films
- 269 Downloads
Spray-deposited tungsten oxide (WO3) nanocrystalline thin films were investigated by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and atomic force microscopy in order to study the precursor induced changes in their structural and morphological properties. The crystallite size and the root mean square surface roughness have been found to be minimum for the WO3 thin films prepared using ammonium tungstate. The optical and spectral studies of the films were carried out using UV–visible spectroscopy and photoluminescence spectroscopy. Electrical transport properties of the films were studied by measuring the film resistivity as a function of temperature. Electrochromic studies of the WO3 films were carried out from cyclic voltammetry, chronocoulometry and chronoamperometry measurements. The films grown using ammonium tungstate exhibit high electrochromic reversibility (~91 %) and large charge storage capacity. The cyclic voltammograms of the films do not change even after 50 scan cycles, confirming the electrochromic stability in the WO3 films. Overall, the film prepared using ammonium tungstate may be a suitable candidate for electrochromic devices.
KeywordsSpray Pyrolysis Cyclic Voltammetry Curve Tungsten Oxide Tungsten Bronze Electrochromic Property
The authors express their gratitude to Centre for Interdisciplinary Research, MNNIT Allahabad, India for providing XRD and AFM facilities. They are grateful to Professor P. Chakrabarti, Director, MNNIT, India for providing electrochemical study measurement facility. They are also thankful to Professor M. Aslam, Department of Metallurgical Engineering and Materials Science, IIT Bombay, India for extending Raman, SEM and PL measurement faculties. Financial support provided by the University Grants Commission, New Delhi, India, in the form of a major research project [No. 40-450/2011 (SR)] is gratefully acknowledged.
- 34.M.A. Wahab, Solid State Physics, 2nd edn. (Narosa Publishing House, New Delhi, 2010), p. 32Google Scholar
- 43.A. Goswami, Thin Film Fundamentals (New Age International, New Delhi, 2005)Google Scholar
- 48.B.M. Sinelnikov, E.V. Sokolenko, V.Y. Zvekov, Inorg. Mater. 32, 999 (1996)Google Scholar
- 49.H.F. Wolf, Semiconductors (Wiley-Interscience, New York, 1971)Google Scholar