Optical Properties of Ce-Doped Li₄SrCa(SiO₄)₂: A Combined Experimental and Theoretical Study

Area of Science:

• Materials Science
• Solid-State Chemistry
• Luminescence

Background:

• Understanding optical properties of lanthanide ions in hosts is crucial for phosphors.
• Cerium (Ce³⁺)-activated phosphors are vital for various technological applications.
• Li₄SrCa(SiO₄)₂ is a promising host material for luminescent applications.

Purpose of the Study:

• To conduct a combined experimental and theoretical investigation of Ce³⁺ optical properties in Li₄SrCa(SiO₄)₂.
• To elucidate the luminescence mechanisms and site occupancy of Ce³⁺ ions.
• To construct an energy-level diagram for lanthanide ions in this host.

Main Methods:

• Solid-state reaction method for material synthesis.
• Photoluminescence spectroscopy from vacuum-ultraviolet (VUV) to ultraviolet (UV) at low temperatures.
• Ab initio theoretical calculations for predicting transition energies.

Main Results:

• Ce³⁺ ions occupy both Sr and Ca sites in the Li₄SrCa(SiO₄)₂ host.
• Broad luminescence observed between 300-500 nm.
• High thermal quenching temperature (>500 K) due to large energy gaps (∼1.40 eV).

Conclusions:

• The study provides fundamental insights into Ce³⁺ optical properties and site preferences in Li₄SrCa(SiO₄)₂.
• The material's properties suggest potential for high-temperature luminescence applications.
• A comprehensive energy-level diagram for lanthanide ions in this host was established.