Electrodeposition of zno thin films : effect of vanadium doping

Date

2013

Author

Avşar, Cemre

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The aim of this study was preparation and characterization of photocatalytically active ZnO thin films on ITO glass sheets by electrodeposition method. In order to investigate the effect of synthesis temperature on the morphology and photocatalytic activity of the thin films, synthesis was performed at room temperature and at 70 °C. Characterizaton of the thin films was carried out by AFM, SEM - EDX, XRD and XPS analysis. Photocatalytic activity of the samples was tested by methylene blue and stearic acid degradation tests. Methylene blue degradation tests were examined by obtaining the absorbance data between 200-800 nm by UV- Vis spectrophotometer. Stearic acid degradation tests were examined by monitoring the difference in the asymmetric C-H streching modes of CH3 groups and the symmetric- asymmetric C-H streching modes of CH2 groups in the region 2700-3000 cm-1 by FT- IR spectrophotometer. ZnO thin films were dip coated with a transition metal, vanadium, in order to investigate the effect of vanadium doping on the photocatalytic activity of thin films. Dip coating was performed with NH4VO3 solutions, in which NH4VO3 was dissolved in water and oxalic acid and vanadium was existing in (+5) and (+4) oxidation states, respectively. Photocatalytic activity tests performed by the degradation of methylene blue and stearic acid on both vanadium doped and undoped ZnO thin films synthesized at room temperature and 70 °C indicated that the photocatalytic activity of thin films had been improved by vanadium doping and it was also favored by the synthesis temperature. It was observed from SEM images that, vanadium was not homogenously dispersed on the surface of the thin films. SEM images also showed the effect of synthesis temperature on the morphology of the ZnO thin films. The oxidation state of vanadium was determined by XPS analysis.

Subject Keywords

Polymers., Pigments., Emulsions.

URI

http://etd.lib.metu.edu.tr/upload/12616401/index.pdf
https://hdl.handle.net/11511/23073

Collections

Graduate School of Natural and Applied Sciences, Thesis