A new melilite-type rare-earth borate CdTbGaB

Area of Science:

• Solid State Chemistry
• Materials Science
• Luminescence

Background:

• Melilite family compounds possess unique crystal structures suitable for optical applications.
• Rare-earth doped phosphors are crucial for developing advanced lighting technologies.

Purpose of the Study:

• To synthesize and characterize a novel mixed metal borate, CdTbGaB2O7.
• To investigate the luminescent properties and color-tunability of CdTb1-xSmxGaB2O7 solid solutions for UV w-LED applications.

Main Methods:

• High-temperature solution method for initial synthesis.
• Single-crystal X-ray diffraction for crystal structure determination.
• Solid-state reaction for creating solid solutions.
• X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Infrared/Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and Photoluminescence (PL) for characterization.

Main Results:

• CdTbGaB2O7 was successfully synthesized and identified as a new member of the melilite family with a specific 3D framework structure.
• CdTb1-xSmxGaB2O7 phosphors exhibited simultaneous green (Tb3+) and orange (Sm3+) emissions under 370 nm excitation.
• Color-tunability from green to orange-red was achieved by adjusting Sm3+ doping concentration, indicating an energy transfer mechanism.
• A quantum yield (QY) of 13.22% was observed for CdTb0.995Sm0.005GaB2O7, with good thermal stability (94% intensity retention at 423 K compared to 303 K).

Conclusions:

• The synthesized CdTb1-xSmxGaB2O7 materials demonstrate potential as color-tunable phosphors.
• These phosphors are suitable for applications in ultraviolet white light-emitting diodes (UV w-LEDs) due to their tunable luminescence and stability.