Dye-Sensitized Solar Cells Based on Porous Hollow Tin Oxide Nanofibers

Porous hollow tin oxide (SnO₂) nanofibers and their composite with titanium dioxide (TiO₂) particles (Degussa P25) were investigated as a photoanode for dye-sensitized solar cells. Incorporation of TiO₂ particles in porous hollow SnO₂ fibers enhanced the power conversion efficiency (η) from 4.06% to 5.72% under 100-mW/cm² light intensity. The enhancement of efficiency was mainly attributed to increase in current density (J_sc) and improvement in fill factor (FF). Increase in J_sc was caused by higher dye loading as indicated by UV-Vis absorption spectra and the improvement in FF was attributed to faster charge transport time as obtained from transient analysis. The microstructure of SnO₂ fibers was studied using transmission electron microscope, scanning electron microscope, and X-ray diffraction. The electron transfer and recombination life times were studied using transient analysis, whereas interfacial charge transfer was studied using electrochemical impedance spectroscopy.