Abstract
In this study, various nanoparticles and fluorine polymer were employed to solidify 1,2-dimethyl-3-propyl-imidazolium iodide (DMPII) based liquid electrolytes in dye-sensitized solar cells (DSCs). A guideline to prepare high-performance clay-like or gel-like electrolytes having high content nanoparticles or polymer was prepared for DSCs. We aimed at fabricating ionic paths between nanoparticles or polymer by chemical bondings. Photovoltaic performances of DSCs containing these quasi-solid state electrolytes were studied as well as the influence of redox couple, solvents, additives and the content of nanoparticles or fluorine polymer. Efficiencies of 9.24% and 7.48% were recorded for the AN and MPN-based electrolytes solidified by 17.5% P25 TiO2 nanoparticles, respectively under illumination of simulated AM 1.5 (100mW/cm-2). After TiCl4 treatment for the TiO2 photo-electrode, the conversion efficiency of a DSCs fabricated using quasi-solid state electrolyte was 9.49%, with values of Jsc, Voc, and FF of 18.08(mA/cm-2), 0.78 V, and 67%, respectively. From the electrochemical impedance spectroscopy (EIS) analysis, it was found that the enhanced conversion efficiencies of the DSCs were associated with the decrease in charge transfer resistance at the TiO2/dye/electrolyte and Warburg diffusion resistance. On the other hand, nanoparticles can inhibit the charge recombination, enhancing the open-circuit voltage of the cells. The long-term stability of these quasi-solid state electrolytes was also studied.