Structure, Linear and Nonlinear Optical Properties of Different Dye-Modified TiO2 Ceramics for Possible Application in Photovoltaics

TiO2 is a highly potential, photoactive and dye-sensitive photocatalyst but its optical properties are further enhanced in the presence of different types of dyes. Dye-modified TiO2 was prepared by the modified sol-gel method. The dyes are methyl orange (MO), potassium permanganate (KMnO4) and beetroot. Analysis was conducted to study the physical, linear and nonlinear optical properties. XRD result suggests that the prepared TiO2 is synthesized in the pure anatase phase. The bandgap is decreased in all the dye-modified TiO2 samples. The dielectric constant, interband transition strength, energy loss functions, Urbach energy, optical conductivity and electrical conductivity were determined. Further, the dispersion parameter of refractive index was discussed as per the single-oscillator model proposed by Wemple and DiDomenico. Moreover, the analyses of nonlinear dispersions like first-order and third-order optical susceptibilities, electrical susceptibilities, nonlinear refractive index and reflection loss were performed. To further investigate the electronic properties, the plasma energy, Penn gap and Fermi energy were also determined.