Solvation Dynamics in Ionic Liquids: What We Have Learned from the Dynamic Fluorescence Stokes Shift Studies

Ionic liquids have generated tremendous excitement as a new class of solvent systems having the potential to serve as an environmentally friendly alternative to the traditionally used volatile organic compounds and have emerged as specialty media or materials for many advanced processes and devices. Solvent reorganization in ionic liquids is a complex process, which differs significantly from that in conventional polar molecular solvents. This Perspective highlights the present understanding of the mechanism and time scale of the dynamics of solvation in ionic liquids obtained from the dynamic fluorescence Stokes shift studies on dipolar molecules taking the related theoretical results into consideration.