Photoluminescent microporous lanthanide silicate AV-21 frameworks

Area of Science:

• Materials Science
• Inorganic Chemistry
• Solid-State Chemistry

Background:

• Lanthanide silicates are a versatile class of materials with potential applications in luminescence and catalysis.
• The AV-21 framework, Na(6)Ln(2)Si(12)O(30).x H(2)O, offers tunable properties through lanthanide ion substitution.

Purpose of the Study:

• To hydrothermally synthesize and structurally characterize lanthanide silicate AV-21 materials.
• To investigate the impact of structural disorder on photoluminescence and energy transfer properties.

Main Methods:

• Hydrothermal synthesis
• Single-crystal synchrotron X-ray diffraction
• Solid-state NMR spectroscopy
• Room-temperature lifetime decay dynamics

Main Results:

• The Sm(3+) analogue (isomorphous with Eu(3+), Gd(3+), and Tb(3+)) revealed disorder in the Si(1) coordination sphere.
• La-AV-21 exhibits a distinct framework structure.
• Lanthanide defect centers disordered over Na(1) sites significantly influence energy transfer.

Conclusions:

• The AV-21 framework demonstrates structural flexibility and microporosity, enabling the incorporation of multiple lanthanide centers.
• Structural disorder in lanthanide defect sites provides a unique platform for studying structure-property relationships in luminescent framework solids.