NASICON-type Na_3.6Y_1.8-xSc_x(PO₄)₃ solid solutions: structure and luminescence

Area of Science:

• Materials Science
• Solid-State Chemistry
• Luminescence

Background:

• Phosphor materials are crucial for various optical applications.
• Understanding structure-property relationships is key to developing advanced phosphors.
• Scandium-substituted sodium yttrium phosphate phosphors (Na_3.6Y_1.8-xSc_x(PO₄)₃) are novel materials.

Purpose of the Study:

• To synthesize and characterize single-phase Na_3.6Y_1.8-xSc_x(PO₄)₃ phosphors for the first time.
• To investigate their structural, thermal, and luminescence properties.
• To explore the impact of scandium substitution on phosphor performance.

Main Methods:

• X-ray diffraction (XRD) for structural analysis.
• Raman spectroscopy to study phase transitions across a temperature range (88–873 K).
• VUV, synchrotron, and electron beam excitation to examine luminescence properties.

Main Results:

• Formation of a homogeneous solid solution with a NASICON-type structure.
• No phase transitions observed within the studied temperature range.
• Intense UV emission attributed to 2pO-3dSc self-trapped excitons under VUV/synchrotron excitation.
• Bandgap estimated at ~8 eV, independent of composition.
• Enhanced luminescence intensity and thermal stability in solid solutions due to structural disorder.

Conclusions:

• Na_3.6Y_1.8-xSc_x(PO₄)₃ phosphors exhibit promising luminescence properties.
• Structural disorder plays a significant role in enhancing exciton emission and thermal stability.
• These findings suggest potential applications in areas requiring efficient UV-emitting materials.