Absorption spectra, thermal analysis, photoelectrochemical characterization and stability test of vegetable-based dye-sensitized solar cells

This work reports an optical and photoelectrochemical study on the use of not edible parts of eggplant in a photovoltaic device. In this paper we employ, for the first time, the leaves and the bark of eggplant twigs, as pigment sources for dye-sensitized solar cells (DSSCs). We compared and discussed both the absorption spectra of two natural extracts and photovoltaic performances in DSSCs. We also compared, for a similar natural sensitizer, our electrolyte respect to several electrolytes reported in literature. Solar power conversion (eta = 1%) and the short circuit current density (Jsc = 8 mA/cm(2)) achieved by studied devices are higher of 27% and 110% respectively, than literature data, so far reported. Furthermore, we demonstrated, by a thermodynamic study, thermal stability up to 125 degrees C of the eggplant extract, when anchored to TiO2 layer, and finally we presented some stability tests, under solar irradiation, of the DSSCs based on this natural extract.