All-solid-state electrolytes consisting of ionic liquid and carbon black for efficient dye-sensitized solar cells

All-solid-state electrolytes-based dye-sensitized solar cells (DSSCs) are constructed using a mixture of carbon black and 1-methyl-3-propylimidazolium iodide (PMII) ionic liquid without the addition of iodine, TiO2/FTO glass, N719, and FTO glass as electrolyte, working electrode, light harvesting material and counter electrode, respectively. The influences of the electrolyte composition (weight ratio of carbon black and PMII), TiO2 film thickness and the compact layer on the photovoltaic parameters of DSSCs have been investigated in detail. Electrochemical impedance spectroscopy (EIS) measurement is used to analyze the influence of electrolyte composition on the photovoltaic performance. The DSSC based on a 16.2 μm TiO2 nanocrystalline film and an all-solid-state electrolytes containing 60 mg carbon black and 100 mg PMII exhibits a power conversion efficiency of 6.37%, short-circuit current density of 15.33 mA cm−2, open-circuit voltage of 644 mV and fill factor of 64.5%, measured at AM 1.5 G one sun (100 mW cm−2) illumination.