Dye-Sensitized Solar Cell Based on Natural Dye Extracted from Buckwheat ( Fagopyrum esculentum ) Flour

Dye-sensitized solar cells (DSSCs) are an economical and environment friendly alternative to conventional silicon based solar cells and have gained significant attention in recent years. In this study a dye-sensitized solar cell (DSSC) based on natural dye extracted from buckwheat ( Fagopyrum esculentum ) flour was fabricated. The polymeric iodide/tri-iodide electrolyte system was used as an electrolyte. The cell was fabricated by depositing nanocrystalline-TiO 2 semiconductor layer synthesized by sol-gel method on transparent fluorine doped tin oxide (FTO) conductive glass using screen printing method. Photovoltaic performance of the cell was evaluated by analyzing its J – V characteristics. The different photovoltaic parameters current density ( J sc ), open circuit voltage ( V oc ), fill factor (FF) and solar conversion efficiency (η) were found to be 0.82 mA/cm 2 , 0.6 V, 0.43 and 0.28%, respectively. The electrochemical properties of the extract were evaluated via cyclic voltammetry. The HOMO–LUMO energy levels were found to be –5.3 and –3.29 eV and Band Gap ( E g ) 2.01 eV. Impedance analysis of the cell carried out by recording Cole-Cole plot between real and imaginary impedances revealed the total internal resistance to be 2.3 kOhm. The performance of the cell was found to be equally good in comparison to pure Rutin based DSSC.