Strong luminescence of rare earth compounds in ionic liquids: Luminescent properties of lanthanide(III) iodides in the ionic liquid 1-dodecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide

Purposely designed ionic liquids can be excellent solvents for spectroscopic studies of rare earth compounds. Absorption, excitation and emission spectra of LnI3 (Ln = Nd, Dy and Tb) in the ionic liquid 1-dodecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide are presented. Electronic transitions were assigned from the energy level diagrams for Ln(III). Emission lifetimes for DyI3 in [C12mim][Tf2N] are discussed. Traces of water dramatically reduce the otherwise long lifetimes and comparatively high quantum yields.