Binuclear Complex of Zinc and Copper with Unsymmetrical Macrocyclic Ligand as Sensitizer in Nanocrystaline TiO2 Solar Cells

Dye sensitized solar cells (DSSCs) are considered as one of the most promising alternativerenewable energy sources. In the structure of DSSCs, a photosensitizer composed of transitionmetal complexes is used to harvest light. In this work a binuclear complex containing twopropionitrile pendant arms [ZnLCu(OAC)]PF6 {L = 1, 6- bis (2-cyanoethyl) -2, 5-bis (2-hydroxy3-formyl-5-methylbenzyl)-2, 5- diazahexane} has been examined as a non-planar metal basedphotosensitizer in the fabrication of dye sensitized solar cell. The photovoltaic performance ofthe fabricated cell was evaluated and photovoltaic parameters were determined. The resultsshowed the conversion efficiency of 0.17%, current density of (Jsc) 0.69 mAcm-2, voltage (Voc)0.38 v and fill factor (FF) of 0.69 under sun (Am1.5) for the cells. Electrochemical impedancespectroscopy (EIS) and cyclic voltammetry (CV) were employed to study the electron transfermechanism in fabricated cells. The results showed that the potential in cathodic current was morepositive indicating that the conduction band position of TiO2 had shifted to positive energiesconfirming less Voc of the fabricated cell.