Ultrabroad near-infrared photoluminescence from ionic liquids containing subvalent bismuth.

We have shown that Lewis-acidic halogenoaluminate ionic liquid (IL) containing subvalent bismuth can be used as a near-IR (NIR) luminescent material. Raman and absorption spectra evidence the coexistence of Bi(5)(3+) and Bi(+) in the liquid. The Bi(5)(3+) and Bi(+) emitters, stabilized by this Lewis-acidic liquid, demonstrate ultrabroad NIR photoluminescence with a lifetime of around 1 μs. We envisage that the bismuth activated ILs would not only enrich the well-established spectrum of soft luminescent materials but also might promote the design of novel photonic materials activated by other p-block elements.