Novel silane-substituted benzimidazolium iodide as gel electrolyte for dye-sensitized solar cells

A novel ionic electrolyte, 3-(iodohexyl)-1-(3-(triethoxysilyl)propylcarbamoyl)-1H-benzo[d]imidazol-3-ium iodide (SSBI) was prepared through the reaction of N-[3-(triethoxy-4-silyl)propyl]-1H-benzimidazole-1-carboxamide with 1,6-diiodohexane for the quasi-solidification of the electrolytic solution of a dye-sensitized solar cell (DSSC). The SSB-containing electrolyte, the sol electrolyte, in a DSSC was converted to a gel by heating it at 60 °C for 30 min in an oven. The DSSC consisting of the gel electrolyte showed a solar-to-electricity conversion efficiency comparable to that of the cell with the reference liquid electrolyte, and consistently higher stability than that of the reference cell. The performances of the DSSCs containing the reference, sol and gel electrolytes were discussed by scanning electron microscopy (SEM), impedance and chronoamperometric measurements, ionic conductivity, and UV–vis absorption spectroscopy.