Effects of hydrochloric acid treatment of TiO2 nanoparticles/nanofibers bilayer film on the photovoltaic properties of dye-sensitized solar cells

The TiO2 nanoparticles/nanofibers bilayer film has been fabricated via spin coating and electrospinning followed by calcination. The TiO2 bilayer film with thickness of about 6.0 μm is composed of anatase TiO2 phase. Dye-sensitized solar cells (DSSC) were assembled by hydrochloric acid (HCl) treated TiO2 film. The results of the photocurrent action spectra, electrochemical impedance spectroscopy (EIS), and I–V curves showed that each photovoltaic parameter of DSSC increased with the concentration of HCl increasing, and reached a maximum value and afterwards decreased. The maximum incident monochromatic photo-to-electron conversion efficiency (at 350 nm) and maximum overall conversion efficiency (η) of 0.05 M HCl treated TiO2 based DSSC were enhanced to 48.0% and 4.75%, which were respectively increased by 14% and 6.3% than those of DSSC based on untreated TiO2 film.