Viscosity and Ionic Conductivity of Imidazolium based Ionic Liquids bearing Triiodide Anion

Abstract

In the electrolyte application for dye sensitized solar cells, utilization of ionic liquids is getting the highlights to replace volatile organic solvent thanks to their low volatility, thermal and electrochemical stability. The iodide/triiodide redox electrolyte is the preferred choice for this application, hence numerous iodide-based ionic liquids have been explored and reported. On the contrary, the transport properties of triiodide based ionic liquid is often lack of reporting despite of having an equal influence on the overall viscosity and ionic conductivity of the electrolyte. In this study, three alkylimidazolium triiodide ionic liquids were synthesized from the respective alkylimidazolium iodide ionic liquids precursors and their physicochemical and conductivity properties are reported. 1H NMR analysis showed a slight shifting of position of the resonances of triiodide based alkylimidazolium ionic liquids as compared to their precursors due to less electronegativity nature of triiodide anion. The formation of triiodide-based imidazolium ILs have dramatically altered the transport properties in which the ionic liquids obtained are of low viscosity and high ionic conductivity.