Optical characterization of nanocrystalline Titanium dioxide (Tio₂) sensitized with natural dyes in the application of Dye Sensitized Solar Cells (DSSCs)

Abstract

This paper optically characterized nanocrystalline titanium dioxide (TiO₂ ) using natural dyes obtained from dacryodes edulis, mimosa  pudica, delonyx regia and xanthosoma saggittifolium leaves to function as dye sensitizers in dye-sensitized solar cell (DSSC). Solvent  extraction method was employed, UV-VIS spectrophotometer was used to obtain the optical absorbance spectra of the sensitized films  while Tauc model was employed to determine the optical band gaps. From UV-Vis absorption spectra, ncTiO₂ sensitized with these  natural dyes have absorbance at wavelength 200-720nm but low transmittance and reflectance in the visible region. This indicated that  the dyes absorb visible light, which improves the optical properties of TiO₂ when sensitized with these natural dyes and have been found  to be suitable for the use as sensitizers in solar cells. Also, their optical band gaps were obtained using Tauc relation, result showed  approximate value of 1.30 × 10−9 eV.