Influence of cations of the electrolyte on the performance and stability of dye sensitized solar cells

Abstract

The electrolyte is one of the key components for DSC and its properties have great influence on the photo-conversion efficiency and stability of the devices. Five new low volatile electrolytes containing 3-methoxypropionitrile (MPN) as solvent were prepared with different cationic structures of the iodide source to evaluate their photovoltaic performance in dye-sensitized solar cells. We are interested in studying the role of cations in the device performance and selected the cations of iodide salts such as 1,3-dimethylimidazolium, 1,2-dimethyl-3-propylimidazolium, 1-ethyl-1-methylpyrrolidinium, tetrabutylammonium and 1-propylpyridinium for comparison. These electrolytes are characterized by measuring the triiodide diffusion coefficients using both electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. In combination with the Ruthenium C106 dye these newly developed electrolytes show an initial power conversion efficiency between 8 and 9% under full sunlight at AM1.5G conditions. The DSC devices prepared with these electrolytes subjected to prolonged aging under full sunlight at 60 °C showed excellent stability. EIS has been employed to characterize the photovoltaic parameter variations observed during the durability tests.