Harnessing Ligand Exchange in Combined Acid Solution for Changing Growth Pattern of Titania Nanorods

Titania (TiO₂) nanorods are meticulously aligned on the fluorine-doped tin oxide (FTO) coating side, while TiO₂ nanoparticles on the plain glass side of the FTO-coated glass substrate are grown using a straightforward one-step hydrothermal method within a single reaction vessel. This study thoroughly analyzes the effects of formic acid (FA) on various aspects, including growth rate, crystal structure, substrate selection, film formation, gas sensitivity, and parameters influencing power conversion efficiency. Several analytical methods, such as scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, Raman spectroscopy, UV-Vis spectrophotometry, and a Solar sun simulator, are employed to assess the efficiency of the photovoltaic system under the effect of the acid mixture. Nanorod arrays (NRAs) formed by combining hydrochloric acid (HCl) and FA solution show significantly better performance compared to those formed using HCl solution alone. The findings suggest that adding FA to the growth solution results in improved uniformity and density of titania NRAs. Consequently, this leads to a larger surface area to adsorb dye molecules in dye-sensitized solar cells or sense target gas in a gas sensor device. This improvement is attributed to the enhancement of both optical and electrical characteristics of the fabricated films and device performance.