Structural and Luminescent Properties of Europium-Doped and Undoped Hydroxyapatite Powders Sintered by Spark Plasma

Abstract

This paper studies the structural and photoluminescent properties of hydroxyapatite (HA) and europium-doped hydroxyapatite (HA:Eu) synthesised by the hydrothermal method and sintered by the spark plasma sintering (SPS) technique. HA and HA:Eu powders, synthesised at pH of 10, 11 and 12, were characterised by means of infrared spectroscopy, X-ray diffraction, scanning electron microscopy, Raman spectroscopy and luminescence spectroscopy. The HA and HA:Eu samples were sintered using the SPS technique at 900 and 1200 °C. It was determined that the HA and HA:Eu powders crystallised in the hexagonal phase, which is stable until 900 °C. The presence of Eu 3+ ions tended to stabilise the hexagonal phase of hydroxyapatite at 1200 °C. Undoped hydroxyapatite sintered at 1200 °C revealed a significant amount of tricalcium phosphate (β-TCP) as a result of its decomposition. By increasing the heat treatment temperature, different emission lines (

Crystal Chemistry and Luminescence Properties of Eu-Doped Polycrystalline Hydroxyapatite Synthesized by Chemical Precipitation at Room Temperature

“…The emissions from Eu at Ca1 are mainly observed for sample at 120 °C ( Figure 6a) and at 450 °C (Figure 6b), while the sample annealed at 900 °C shows typical transition of Eu at Ca2 site ( Figure 6c), in agreement with [13].…”

“…This is in agreement with [39], although different from the sample annealed at high-T (Eu-HAp900), where Eu occupies Ca2 (s.o.f. : Ca0.98Eu0.02), which is found to be true for most Eu-doped HAps [13,29]. As observed above, the shortening of Ca2-O distances (Table 5) for increasing annealing temperature, may induce the migration of europium from the Ca1 to the Ca2 site, as observed in many HAp structures found in the Inorganic Crystal Structure Database [38].…”

Structural, Spectroscopic, and Biological Characterization of Novel Rubidium(I) and Europium(III) Co-Doped Nano-Hydroxyapatite Materials and Their Potential Use in Regenerative Medicine

“…Figure 5A,B, show the most intense peak corresponding to the 5 D 0 → 7 F 2 transition. The peaks corresponding to this transition are observed at wavelengths in the range of 605-630 nm, with a maximum intensity at 616.7 nm [9,10,15,37]. Furthermore, the strictly forbidden transition of Eu 3+ ion form the level 5 D 0 to 7 F 0 is well observed.…”

A Study of Vanadate Group Substitution into Nanosized Hydroxyapatite Doped with Eu3+ Ions as a Potential Tissue Replacement Material

“…As one of the rarest of the rare-earth elements and the most reactive element so far, europium exhibits relatively non-toxic effects on living cells [ 25 , 26 , 27 ]. Moreover, europium(III) ions can improve bone density and metabolism, especially when loaded in calcium-based compounds such as hydroxyapatite [ 28 , 29 ]. By obtaining the high crystal structure of the host material, Eu 3+ ions loaded in hydroxyapatite show a high intensity of luminescence and can be used as a biocompatible biosensor for imaging cells or tissues.…”