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 alternative renewable energy sources. In the structure of DSSCs, a photosensitizer composed of transition metal complexes is used to harvest light. In this work a binuclear complex containing two propionitrile pendant arms [ZnLCu(OAC)]PF6 {L = 1, 6- bis (2-cyanoethyl) -2, 5-bis (2-hydroxy 3-formyl-5-methylbenzyl)-2, 5- diazahexane} has been examined as a non-planar metal based photosensitizer in the fabrication of dye sensitized solar cell. The photovoltaic performance of the fabricated cell was evaluated and photovoltaic parameters were determined. The results showed 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 impedance spectroscopy (EIS) and cyclic voltammetry (CV) were employed to study the electron transfer mechanism in fabricated cells. The results showed that the potential in cathodic current was more positive indicating that the conduction band position of TiO2 had shifted to positive energies confirming less Voc of the fabricated cell.