Synthesis and Characterization of Eu²⁺/Nd³⁺ Activated CaSi₂O₅ Phosphor for Bioimaging Applications

Area of Science:

• Materials Science
• Biomedical Engineering
• Nanotechnology

Background:

• Non-invasive diagnostic tools are crucial in modern medicine.
• Luminescent nanomaterials offer enhanced imaging capabilities.
• Calcium silicate (CaSi₂O₅) is a biocompatible host matrix.

Purpose of the Study:

• To synthesize and characterize Eu²⁺/Nd³⁺ codoped CaSi₂O₅ phosphors.
• To evaluate their potential for bioimaging applications.
• To investigate their luminescent properties for deep-tissue excitation.

Main Methods:

• Solid-state reaction under a reducing environment.
• X-ray diffraction (XRD) for structural analysis.
• Field emission gun scanning electron microscopy (FEG-SEM) for microstructure.
• Energy-dispersive X-ray spectroscopy (EDX) for elemental analysis.
• Fourier-transform infrared (FTIR) spectroscopy for bond confirmation.
• Photoluminescence spectroscopy for excitation and emission spectra.
• Afterglow decay and CIE chromaticity analysis.

Main Results:

• Formation of triclinic CaSi₂O₅ with Eu²⁺/Nd³⁺ doping.
• Flower-like microstructures observed via FEG-SEM.
• Nd³⁺ (near-infrared sensitizer) absorption bands (700-1000 nm).
• Eu²⁺ dual blue emission bands (~410 nm and ~440 nm) upon ~800 nm excitation.
• Persistent luminescence >15 minutes.
• High chromatic accuracy (x=0.155, y=0.059).

Conclusions:

• Eu²⁺/Nd³⁺ codoped CaSi₂O₅ phosphors are successfully synthesized.
• The material exhibits excellent luminescent properties suitable for bioimaging.
• Potential for background-free biomedical imaging with high chromatic accuracy.