High conversion efficiency of pristine TiO2 nanotube arrays based dye-sensitized solar cells

We prepared highly-ordered titanium dioxide nanotube arrays (TNAs) by anodizing Ti foils in F⁻-containing electrolytes. The crystalline nature and morphology of the TNAs were studied using X-ray diffraction patterns and scanning electron microscopy. We found the morphology of TNAs affects the light-to-electricity conversion efficiency (η) of dye-sensitized solar cells (DSSCs). The efficiency of DSSCs reached 5.95% under the condition of light illuminated from the counter electrode. The high efficiency of TNA-based DSSCs was attributed to the neat top surface of TNAs, which allows more dye molecule loading on the surface of the TiO₂ nanotubes, and fewer electron recombination centers and a low interface resistance of integrated TNAs.