Journal article

Effect of Cation on Dye Regeneration Kinetics of N719-Sensitized TiO2 Films in Acetonitrile-Based and Ionic-Liquid-Based Electrolytes Investigated by Scanning Electrochemical Microscopy

Scanning electrochem. microscopy (SECM) in the feedback mode was used to study the kinetics of dye regeneration on cis-di(thiocyanato)-bis(2,2'-bipyridyl-4,4''-dicarboxylate) Ru(II)-sensitized TiO2 photoelectrochem. electrodes in contact with room temp. ionic liqs. electrolytes. MeCN based electrolytes were used for comparison. The data are analyzed with the help of a revised model for relating steady state approach curves in the SECM feedback mode to an effective rate const. for the dye regeneration process. This effective rate const. summarizes the effect of electron transfer kinetics, mass transport of the mediator inside the porous electrode, and recombination processes. The authors found a remarkable dependence of the dye regeneration on the nature and concn. of deliberately added cations.


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