Optical and structural properties of europium-doped hydroxyapatite

Europium-doped hydroxyapatite (0 ≤ x ≤ 0.3) was synthesized using the hydrothermal method and thermally treated from 200 to 800 °C. Our results revealed the formation of Europium phosphate (EuPO4) as a second phase above 0.05%, leading to improved emission properties. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), and Raman spectroscopy. The optical properties were measured with diffuse reflectance and luminescence spectroscopy, showing that the combination of Europium-doped hydroxyapatite and EuPO4 enhanced the emission properties. The highest emission intensity was observed at 800 °C and HA: 0.2Eu. These results have potential applications for biomedical imaging and sensing.