Synthesis and characterization of iron-doped TiO2 nanotubes for dye-sensitized solar cells

Titanium dioxide nanotubes as materials for energy conversion were successfully synthesized, characterized and tested for dye-sensitized solar cells (DSSC). The TiO₂ nanotubes were grown by one face anodization at room temperature on titanium sheets of 0.25 mm thickness and 99.7 % purity. The electrolyte was composed of ethylene glycol, ammonium fluoride (0.3 wt. % NH₄F), deionized water (2 vol. % deionized water) and Fe(NO₃)₃ as dopant source with varying concentrations of 2, 4, 6 and 10 mM. The X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and ultraviolet–visible spectrometry (UV-vis) techniques were used to characterize the TiO₂nanotubes. Finally, the samples were tested in dye-sensitized solar cells and their conversion efficiencies were calculated. According to the results, amorphous TiO₂ was transformed into the crystalline anatase phase after heat treatment. Under the given experimental conditions, our optimal results were obtained for the titanium dioxide nanotubes (TNTs) at 6 mM of iron (III) nitrate. The maximum DSSC conversion efficiency was 4.66 % for the TNTs of 6 mM Fe(NO₃)₃. The findings of this research provide significant guidelines for current and future research in the development of renewable energy.