Acceleration of redox diffusion and charge-transfer rates in an ionic liquid with nanoparticle addition

The exchange-reaction-based diffusion and the interfacial charge-transfer rates of an iodide/triiodide redox couple in an ionic liquid were enhanced by the addition of SiO2 nanoparticles, although the composites successively became gels and solids with increasing nanoparticle composition. Because of this acceleration of the charge transport and the interfacial charge-transfer rates, dye-sensitized solar cells using the composite electrolytes achieved high photon-to-current conversion efficiencies, comparable to those using the neat ionic liquid electrolyte. (c) 2007 The Electrochemical Society.