Synthesis, Characterization and Application of Nanoporous TiO2 as Photoanode for DSSC Sensitized by a Natural Dye Extracted from "Mesua Ferrea"

Abstract

Nanoporous TiO₂ is preferred as the wide band gap semiconductor in  dye sensitized solar cells (DSSC) due to its high photo catalytic activity, high adsorption potential, anticorrosion properties, chemical stability and eco-friendliness. The key difference of the DSSC over traditional single junction solar cells is the use of a sensitizer dye, which broaden the absorption frequency of the wide band gap semiconductor and thereby increase the efficiency of the photo electrode. Natural dyes as photosensitizer are getting prime importance in recent years due to their availability, low cost and environmental friendliness. In this work, we have reported the synthesis of nanoporous TiO₂ thin film on a transparent conducting oxide (TCO) glass substrate by a modified sol-gel technique using titanium isopropoxide as the precursor. The as synthesized films were characterized by UV-vis spectroscopy, X - diffraction (XRD) and transmission electron microscope (TEM) for the investigation of their optical, structural and morphological properties. One natural dye was extracted from locally available young red leaves of "Mesua ferrea using water and alcohol as solvents at different temperatures. For the fabrication of the TiO₂   photoanode, the as synthesized films were dipped into the dye extracts and the sensitization efficiency as well as the HOMO-LUMO interaction between the dye and TiO₂ was investigated through UV –vis spectroscopy.