Effect of TiO₂ nanotube length and lateral tubular spacing on photovoltaic properties of back illuminated dye sensitized solar cell

Abstract

The main objective of this study is to show the effect of TiO₂ nanotube length, diameter and intertubular lateral spacings on the performance of back illuminated Dye Sensitized Solar Cells (DSSCs). The present study shows that processing short TiO₂ nanotubes with good lateral spacings could significantly improve the performance of back illuminated DSSCs. Vertically aligned, uniform sized diameter TiO₂ nanotube arrays of different tube lengths have been fabricated on Ti plates by a controlled anodization technique at different times of 24, 36, 48 and 72 h using ethylene glycol and ammonium fluoride as an electrolyte medium. Scanning Electron Microscopy (SEM) showed formation of nanotube arrays spread uniformly over a large area. X-ray Diffraction (XRD) of TiO₂ nanotube layer revealed the presence of crystalline anatase phases. By employing the TiO₂ nanotube array anodized at 24 h showing a diameter ∼80 nm and length ∼1•5 μm as the photo-anode for back illuminated DSSCs, a full-sun conversion efficiency (η) of 3•5% was achieved, the highest value reported for this length of nanotubes.