High-temperature and long-term stable solid-state electrolyte for dye-sensitized solar cells by self-assembly

Ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate was solidified by silica nanoparticles (>2 wt%) even up to 85°C. The mechanism of solid-state composites was inferred to self-assemble through hydrogen bond networks between the anion BF₄^- and the hydroxyl group in the surface of silica nanoparticles, which was characterized by differential scanning calorimetry measurement and Fourier transition infrared spectra. The solid-state composite was introduced to form high-temperature solid-state electrolytes for highly efficient dye-sensitized solar cells with an overall energy-conversion efficiency of 4.7% at room temperature and 5.0% at 60°C under AM 1.5 sunlight illumination (75 mW cm^-2).