Eu(2+) luminescence in strontium aluminates

Area of Science:

• Materials Science
• Solid State Chemistry
• Luminescence

Background:

• Strontium aluminates doped with europium (Eu(2+)) are investigated for their luminescence properties.
• The Sr/Al ratio influences the host lattice's local coordination and covalency.

Purpose of the Study:

• To explore how local coordination and covalency in strontium aluminates affect Eu(2+) optical properties.
• To understand the relationship between the Sr/Al ratio and Eu(2+) luminescence characteristics.

Main Methods:

• Recording UV and VUV excited luminescence spectra.
• Analyzing luminescence decay curves.
• Characterizing luminescence properties of various strontium aluminates (SrAl12O19, SrAl4O7, Sr4Al14O25, SrAl2O4, Sr3Al2O6).

Main Results:

• Eu(2+) emission spans UV to red, influenced by crystal-field splitting and oxygen covalency.
• SrAl12O19:Eu(2+) shows narrow UV emission, while Sr3Al2O6:Eu(2+) exhibits yellow-red emission.
• Increasing Sr/Al ratio shifts Eu(2+) emission to longer wavelengths.

Conclusions:

• The emission color of Eu(2+) in strontium aluminates can be tuned across a wide spectral range.
• Local coordination and covalency are key factors controlling Eu(2+) luminescence in these materials.
• Differences in Eu(2+) emission from various crystallographic sites are observed, not always correlating with the oxygen coordination sphere.