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–V curve) 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 (Jsc) 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.