A quasi-solid-state dye-sensitized solar cell based on a sol-gel nanocomposite electrolyte containing ionic liquid

TiO2 dye-sensitized quasi-solid-state solar cells have been constructed by employing a nanocomposite organic/inorganic gel electrolyte made by the sol-gel method. The nanocomposite gel is based on silica while its organic subphase is a mixture of a surfactant (Triton X-100), an organic solvent (propylene carbonate), iodine, and 1-methyl-3-propylimidazoliumiodide, which is an ionic liquid (molten salt). The last two components produce a I-3(-)/I- redox couple. Improved results were obtained by also adding N-methylbenzimidazole. Time-resolved luminescence quenching analysis, dark dc conductivity measurements, and cell efficiency measurements were used to determine the optimal composition of the gel for maximum cell efficiency, which in the present case was 5.4%.