Redox Reaction Mechanisms with Non-triiodide Mediators in Dye-Sensitized Solar Cells by Redox Potential Calculations

We investigate reaction mechanisms of the redox mediators in dye-sensitized solar cells through systematic calculations of redox potentials of possible cobalt complexes and iodides in acetonitrile solution by use of the thermodynamic cycle method with continuum solvent model. The calculated redox potentials were in good agreement with the experimental values, although the experimentalists used different reference electrodes. The maximum open circuit voltage (V-OC) of the mediators calculated in this work indicate that the I-2(center dot-)/2I(-) and I-2/I-2(center dot-) as well as the net I-2/2I(-) redox reactions can dominate at both photoanode and counter-electrode.