Characterization of Dye Sensitized Solar Cells Sensitized with the Extract of Trigonella foenum-graecum Seeds

Abstract

Dye sensitized solar cells (DSSCs) are considered as one of the main axis for search during the last few years due to low production cost. The purpose for this thesis was to prepare DSSCs by using Titanium dioxide (TiO2) as a semiconducting layer, FTO as conducting substrates, and ten natural dyes extracted from plant seeds such as Trigonella foenum-graecum, Apium graveolens, Rhus, Piper nigrum, Petroselinum, Ocimumbasilicum, Ammi, Peganum, Linum, and Lepidium virginicum. The absorption spectra of the ten natural dyes and current-voltage curves of the fabricated DSSCs were carried out. The results showed that the Trigonella foenum-graecum was the best dye. The effect of acid treatment of FTO substrate and TiO2 layer was carried out using different acids. The effects of changing pH of the extracted dye solutions and of addition of ZnO layer on TiO2 film on the performance of DSSC were examined. The results showed an efficiency drop when FTO and TiO2 were treated by different acids and when changing pH of the extracted dye solutions. Moreover, when ZnO layer was added the efficiency also decreased. On the other hand, the fill factor of the DSSCs sensitized with Trigonella foenum-graecum exhibited an improvement when FTO was treated by H3PO4 and HNO3 and when TiO2 was treated by HNO3. For DSSCs sensitized with Apium graveolens, the fill factors showed an enhancement when TiO2 was treated with HNO3 and HCl acids and the open circuit voltage was improved when FTO was treated with H3PO4 and HNO3 acids. An enhancement of the open circuit voltage and fill factor was observed when the ZnO layer was added to the TiO2 film.