Comprehensive Study of Cobalt doped TiO2 Thin Films for Photo Catalytic Applications

Abstract

In this study, Pure and Cobalt (Co) doped titanium dioxide (TiO₂) thin films on glass substrate were prepared by using sol-gel dip coating process. The effects of Co doping on the structural, optical and photo catalytic properties of TiO₂ thin films were investigated. The as-prepared films were annealed at temperature 500°C for 1h and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL) and UV-Visible spectroscopic studies. The XRD patterns and AFM images revealed a polycrystalline structure for all samples. PL spectra shows that charge separation increased upto 0.5 mol% Co doped TiO₂ thin films. Optical band gap, refractive index, optical conductivity and extinction coefficients of these films were determined using transmittance spectra.  Band gap energy of the Co doped anatase TiO₂ films is found to decrease with increasing Co concentration. The refractive index was found to increase from 2.12 to 2.33 with increase in Co concentration from 0 to 1.0-mol %. The optimal Cobalt doping concentration is 0.5 mol% for better photo catalytic activity as supported by Photoluminescence spectra.