Influence of Cu concentration on the structural, morphological, optical and catalytic properties of TiO2 thin films

Abstract

Pristine titanium oxide (TiO₂) and Cu doped TiO₂ thin films of ~2.0 µm thicknesses have been deposited on glass substrates by sol-gel dip coating technique. The deposited films are even and more adherent to the substrate. The consequences of incorporation of Cu ions of different concentration in TiO₂ lattice towards the structural, morphological and optical characteristics of prepared thin films have been investigated. Cu doping alters crystallite size and morphology of doped TiO₂ films marginally. Gradual increase in concentration of Cu atoms into TiO₂ matrix expands the absorption window of prepared films to visible region. The decrease in excitonic energy upon Cu doping promotes the charge separation in TiO₂ semiconductor. Depending upon Cu concentration, exciton life time is extended fairly which leads to improved electron-hole separation and enhanced oxidation-reduction reactions at the surface of TiO₂ semiconductors. The advantage of thin film catalyst over the other catalyst structures has been exhibited by the reusability nature of Cu-TiO₂ films. This study reveals that an ideal amount of Cu doping can increase the photocatalytic performance of TiO₂ thin films efficiently.