Ionic liquids as tunable refractive index fluids

In this contribution we simulate the refractive index of several ion combinations yielding ionic liquids. The results show that their structural tunability can be exploited to successfully design liquids with task-specific refractive indices over a wide range of values, even higher than 2.0. Some designing clues are provided, being charge delocalization and the presence of fluorine atoms key factors to reach ion combinations with the highest refractive index possible.