Luminescent Materials Based on Tb- and Eu-Containing Layered Double Hydroxides (original) (raw)

One of the central problems of functional materials science concerns the design of new luminescent materials with high optical characteristics. Of special interest are luminescent materials based on rare-earth compounds since they provide monochromatic emission with high quantum yields . Among them, terbium and europium compounds are the most widely used due to their efficient visible luminescence . The drawback of the luminescence of rare earths is that their dipole-allowed transitions within the 4 f shell are parityforbidden; this forbiddenness can be partially lifted by splitting in the crystal field. The luminescence efficiency of rare earths can also be increased through sensitization by organic ligands . However, the use of free molecular complexes is made difficult by concentration effects (luminescence quenching), high energies lost by phonon vibrations, and instability of these complexes under external action . One promising strategy for solving these problems involves intercalation of rare-earth complexes into a chemically inert and optically transparent matrix (mesoporous molecular sieves, zeolites, polymers ).