Enhanced Efficiency of Dye-Sensitized Solar Cells Using Anodic Titanium Oxide Nanotube Arrays

This paper concerns the microstructure of the anodic titanium oxide (ATO, TiO2) nanotube (NT) and its use for the dye-sensitized solar cell (DSSC) device. The ATO length was controlled by various electrolytes and anodic time at various constant applied voltages. The lengths of the NTs at 0.3-0.5 and 0.9-22 mu m were controlled by 0.5 vol % HF and 0.58 wt % KF aqueous solutions for varied periods of anodization (1-24 h). The 0.5 wt % NH4F electrolyte in ethylene glycol can produce 4-41 mu m for varied periods of anodization (0.5-8 h). ATO made of 0.3 (0.5 vol % HF), 12 (0.5 wt % KF), and 18 mu m (0.5 wt % NH4F) was used for the DSSC anode; the best cell performance attained 0.13, 3.76, and 6.18%. The DSSC made of 18 mu m ATO has a short-circuit current density (J(sc)) of 13.45 mA/cm(2), a fill factor of 0.64, an open voltage (V-oc) of 0.72 V, and a photocurrent efficiency of 6.18% under an air mass 1.5 illumination test.