Effect of copper doping on the photocatalytic activity of ZnO thin films prepared by solegel method
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Date
2015
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Elsevier
Abstract
In the present work, we prepared undoped and copper doped ZnO thin films by the sol
egel dip coating method on glass substrates from zinc acetate dissolved in a solution of
ethanol. The objective of our work is to study the effect of Cu doping with different
concentrations on structural, morphological, optical properties and photocatalytic activity
of ZnO thin films. For this purpose, we have used XRD to study the structural properties,
and AFM to determine the morphology of the surface of the ZnO thin films. The optical
properties and the photocatalytic degradation of the films were examined by UVevisibles
spectrophotometer. The Tauc method was used to estimate the optical band gap. The XRD
spectra indicated that the films have an hexagonal wurtzite structure, which gradually
deteriorated with increasing Cu concentration. The results showed that the incorporation
of Cu decreases the crystallite size. The AFM study showed that an increase of the concentration
of Cu causes the decrease of the surface roughness, which passes from 20.2 for
Un-doped ZnO to 12.16 nm for doped ZnO 5 wt% Cu. Optical measurements have shown
that all the deposited films show good optical transmittance (77%e92%) in the visible
region and increases the optical gap with increasing Cu concentration. The presence of
copper from 1% to 5 wt% in the ZnO thin films is found to decelerate the photocatalytic
process.