Fabrication of dye-sensitized solar cells using ordered and vertically oriented TiO2 nanotube arrays with open and closed ends

Highly ordered and vertically oriented TiO₂ nanotube arrays were prepared and applied to dye sensitized solar cell (DSSC) as working electrodes. The nanotube arrays were fabricated using atomic layer deposition and AAO template. The two types of nanotube's end, closed-end and open-end, were produced by reactive ion etching (RIE) process. The structure of nanotube arrays was characterized by FE-SEM, TEM, and XRD. DSSCs using the TiO₂ nanotube arrays as working electrodes were fabricated and characterized. The DSSCs prepared from the TiO₂ nanotubes with open end exhibited higher power conversion efficiency of 1.17% than that with closed end. This result is attributed to that the open-ended TiO₂ nanotubes provided larger surface area, leading to more amount of dye molecules to adsorb followed by the higher light absorption.