Nanocomposite Semi‐Solid Redox Ionic Liquid Electrolytes with Enhanced Charge‐Transport Capabilities for Dye‐Sensitized Solar Cells

The ability of Pt nanostructures to induce the splitting of the II bond in iodine (triiodide) molecules is explored here to enhance electron transfer in the iodine/iodide redox couple. Following the dispersal of Pt nanoparticles at 2 % (weight) level, charge transport was accelerated in triiodide/iodide‐containing 1,3‐dialkylimidazolium room‐temperature ionic liquid. If both Pt nanoparticles and multi‐walled carbon nanotubes were introduced into the ionic‐liquid‐based system, a solid‐type (nonfluid) electrolyte was obtained. By using solid‐state voltammetric (both sandwich‐type and microelectrode‐based) methodology, the apparent diffusion coefficients for charge transport increased to approximately 1×10 −6  cm 2  s −1 upon the incorporation of the carbon‐nanotube‐supported iodine‐modified Pt nanostructures. A dye‐sensitized solar cell comprising TiO 2 covered with a heteroleptic Ru II ‐type sensitizer (dye) and the semisolid triiodide/iodide ionic liquid electrolyte admixed with carbon‐nanotube‐supported Pt nanostructures yielded somewhat higher power conversion efficiencies (up to 7.9 % under standard reporting conditions) than those of the analogous Pt‐free system.