Novel light-emitting clays with structural Tb 3+ and Eu 3+ for chromate anion detection.

Tb 3+ and Eu 3+ ions were encapsulated for the first time in the inorganic layers of a synthetic saponite clay following a one-pot synthetic approach. The co-presence of the two metal ions led to tuneable light-emitting properties, promoted by an efficient Tb 3+ → Eu 3+ energy transfer and enhanced Stokes shift character. To our knowledge, the so-prepared luminescent material was tested for the first time as an optical sensor for the detection of chromate anions in water.