Zinc-porphyrin-imide type sensitized TiO₂ nanotube arrays as photoactive electrode in a dyes sensitized solar cell

In this work, TiO₂ nanotube was prepared by rapid breakdown electrooxidation of Ti foil in electrolyte containing 0.15 M HClO₄. The obtained TiO₂ nanotube bundling powder was calcinated at 450°C for 3 hours, then characterized by SEM, XRD, UV-Vis DRS, and BET. Zinc-porphyrin-imide dyes was deposited into TiO₂ nanotube by immersion of TiO₂ nanotube in zinc-porphyrin-imide solution for 24 hours. Free zinc-porphyrin-imide dyes shows characteristics of absorption spectra in visible region at 439 nm and 620 nm. Meanwhile, when it was immobilized to TiO₂-nanotube, the absorption peak shifted to 421 nm and 640 nm. The zinc-porphyrin-imide/TiO₂ electrode showed an excellent response toward the visible light with the typical photocurrent density of 1.1 mA/cm². When the fabricated photoelectrode was assembled in a typical Dyes Sensitize Solar Cell (DSSC), the I-V curve showed photoconversion efficiency of the assembled zinc-porphyrin-imide/TiO₂ DSSC was 1.914% (front side illumination) and 1.147% (backside illumination), respectively. (paper)