Solvation dynamics in room temperature ionic liquids: Dynamic Stokes shift studies of fluorescence of dipolar molecules

Room temperature ionic liquids (RTILs) have attracted tremendous interest in recent years as promising media, which could be an alternative to the environmentpolluting, volatile common organic solvents. In this article, we focus on the studies of dynamic Stokes shift of the fluorescence spectra of dipolar solutes in RTILs. These studies throw light on the nature of solvation dynamics in media that are conceptually quite different from the conventional solvents. A brief introduction to the RTILs and results of some relevant spectroscopic studies have been provided prior to the presentation of the results of dynamic Stokes shift studies. The experimental results on solvation dynamics have been discussed along with theoretical simulation studies. The current understanding of the solvation process in these media, which includes the various timescales and the mechanism of solvation dynamics, is presented to highlight the need and scope for further studies in this area.