Ionic diffusion in various electrolytes and the implications for dye-sensitized solar cells

The diffusion of I-3(-) in volatile and non-volatile electrolytes is investigated to confirm the effects on the performance of dye-sensitized solar cells (DSSCs). The ionic diffusion is controlled by using electrolyte mediums with diverse viscosities including acetonitrile, 3-methoxy-propionitrile, diethylene glycol dimethyl ether, and poly(ethylene glycol dimethyl ether) with three different molecular weights and varying I-3(-) concentrations. The diffusion flux in each electrolyte is characterized by scanning electrochemical microscopy. By measuring incident photon to current conversion efficiency, electrochemical impedance spectroscopy, and photovoltaic performance, the optimum diffusion flux of I-3(-) is suggested for the best efficiency of DSSCs. (C) 2010 Published by Elsevier B.V.This work was supported by a KIST internal project under contract 2E20980. We would like to thank Dr. Nam-Gyu Park at the Solar Cell Research Center at KIST for use of the IPCE and impedance measurements