Tahmineh Jalali

In this paper, the efficacy of wild natural dyes as the sensitizer was investigated for the fabrication of natural dyesensitized solar cells (DSSCs). The natural pigments were extracted from Crocus sativus (Saffron), Allium cepa L (red onion), Malva sylvestris (Mallow), and Oregano (Origanum vulgare) using solvent extraction method. Based on the UV–vis results, the extracted solutions have been shown to contain anthocyanin or chlorophylls pigments, which are excellent pigments required for the charge-carriers generation in the energy harvesting process from the sunlight. The efficacy of all sensitizers has been evaluated using the cyclic voltammetry and current-voltage open circuit experiments of the fabricated DSSCs. The photovoltaic performance of DSSCs in terms of efficiency, current, voltage, and filling factors was performed under standard illumination of AM 1.5G having an irradiance of 100mWcm?? 2. The results showed that the photoelectric conversion efficiency of the fabricated DSSCs were nearly less than 2%, while the open-circuit voltage and short-circuit current density were from 0.43 to 0.55 V and 0.45–0.54 mAcm-2, respectively. The appropriate LUMO energy level and the band-gap of these extracted dyes would enable them to become efficient sensitizer for utilizing in fabricated DSSCs. Therefore, due to the existence of carbonyl and hydroxyl groups in dye’s chemical structures, it enable them to bind to the TiO2layer, consequently, improve the electron transfer, and enhance the energy conversion efficiency of the fabricated DSSC.