Improvement of power conversion efficiency by tailoring of energy band gaps in Ag doped TiO2–SnO2 nanocomposites

Abstract

The Ag doped TiO2–SnO2 nanocomposites with different ratios of TiO2 and SnO2 are prepared by solvo-hydrothermal method. The presence of all the elements were confirmed by XPS spectroscopy in a nanocomposite sample, and also by SEM-EDX characterization. The Raman spectra confirm the rutile to rutile-anatase mixed phase transformation by having respective vibrational modes in all nanocomposites. The UV plots confirm the presence indirect band gap and the red shift by increasing SnO2 content. Adding of SnO2 content increases the PL intensity gradually. In the electrochemical property studies, Ag–90TiO2–10SnO2 shows close to an ideal capacitor nature, whereas increasing SnO2 ratio deviates the capacitor behaviour and exhibits lower impedance. During the photocurrent J-V characteristic of the fabricated DSSCs using prepared Ag doped TiO2–SnO2 nanocomposites, power conversion efficiency is also increased with SnO2 content. Physical behaviours are discussed with energy level band gap diagram, and these points suggest that Ag–60Ti–40Sn nanocomposite is a promising candidate for photoactivity.