Electrochemical characterization of a novel iodine-free electrolyte for dye-sensitized solar cell

The triiodide ions in the triiodide/iodide redox electrolyte have the disadvantages of corrosion and spectrum absorption, which limits the further application of dye sensitized solar cell (DSSC). In this paper, an iodine-free electrolyte without the addition of iodine into iodide-based electrolyte was developed and the electrochemical performance of this novel electrolyte was evaluated by investigating the influence of iodine concentration on the performance of the electrolytes through UV-vis absorbance spectroscopy, Raman spectrum, current-voltage performance (I-Vcurve) and electrochemical impedance spectroscopy (EIS) methods. The results indicate that the iodine-free electrolyte could serve as an efficient mediator for DSSC operation. Owing to the absent of the triiodides generated by iodine, the iodine-free electrolyte has low charge recombination and fast electron transport characteristics, leading to relative high open circuit voltage (Voc). However, acceptable short circuit current (J_sc) was obtained due to the mass transport limitation for iodine-free electrolyte. The results indicate that the iodine-free electrolyte has a potential high performance for DSSC.