Improving the current density and reducing the recombination rate of dye sensitized solar cells by modifying the band gap of Titania using Novel heterostructures

Abstract

Here we report the synthesis of thin films of pristine TiO2, 1% Cd-doped TiO2 (Cd–TiO2), TO2/Cd–TiO2, and Cd–TiO2/TiO2 on FTO glass substrates using the sol-gel dip-coating method. XRD shows that all films have an anatase crystal phase. The maximum intensity and large grain size (48.89 nm) in a 1% Cd–TiO2/TiO2 bilayer film have been observed. Detailed optical properties like absorbance, transmittance, band gap energy (Eg), refractive index (n), dielectric constant, and extinction coefficient (k) have been calculated by UV–Vis. Spectroscopy. According to UV–Vis results, all films absorb UV radiation and transmit visible radiation. The film of 1% Cd–TiO2/TiO2 is a good electrode for solar cell applications due to its low Eg (2.9 eV) and strong transmittance in the visible region. The dye-sensitized solar cells (DSSCs) of these films have been prepared with N719 dye. The cell made up of 1% Cd–TiO2/TiO2 photoanode has the maximum power conversion efficiency (2.47%) in comparison with a pure TiO2 photoanode (1.32%) due to an improvement in the transfer of electrons from the LUMO of dye to the conduction band of TiO2.