Photoluminescent Layered Lanthanide Silicate Nanoparticles

The first examples of nanoparticles of pure layered Ln₂(SiO₄H)(OH)₂(H₂O)Cl (where Ln = Eu, Gd, and Tb) and mixed microcrystalline layered lanthanide silicates containing different Eu/Gd and Tb/Gd ratios have been reported. The crystal structure of these silicates has been solved from synchrotron powder X-ray diffraction data. These materials display interesting and tuneable photoluminescence (PL) properties, such as energy transfer between different Ln³⁺ centers, illustrated here with the pairs Eu³⁺/Gd³⁺ and Tb³⁺/Gd³⁺. The PL properties of the mixed Eu³⁺/Gd³⁺ sample change upon F^– for Cl⁻ ion exchange, and this raises the possibility that this material may be exploited for sensing these ions.