Synthesis of TiO2 nanotube array thin films and determination of the optical constants using transmittance data

•A sophisticated but facile route is introduced to fabricate ZnO template TiO2 nanorods.•Structural and compositional and morphological aspects were studied.•High transparent thin film yielded.•Transmittance data were used to simulation of optical properties by Levenberg–Marquardt algorithm.

TiO2 nanotube arrays were grown on glass substrate by ZnO nanorod sol–gel template process. XRD analysis and FESEM microscopy were employed to characterize the structural and morphological properties of the prepared nanotube. EDX and UV–Vis spectroscopy were used to assess the chemical composition and study the optical properties of the film. An optical model has been performed to simulate the optical constants and thicknesses of the films from transmittance data using the Levenberg–Marquardt algorithm via Drude model. The simulated transmittance is in good agreement with the measured spectrum in the whole measurement wavelength range. The refractive index and extinction coefficient, thickness and dielectric function of TiO2 nanotube films were calculated by Drude model. Also, the related absorption coefficient, optical bandgap and porosity were determined.