Enhancing the luminescence of Eu³⁺/Eu²⁺ ion‐doped hydroxyapatite by fluoridation and thermal annealing

Abstract

This paper reports a novel way for the synthesis of a europium (Eu)-doped fluor-hydroxyapatite (FHA) nanostructure to control the luminescence of hydroxyapatite nanophosphor, particularly, by applying optimum fluorine concentrations, annealed temperatures and pH value. The Eu-doped FHA was made using the co-precipitation method followed by thermal annealing in air and reducing in a H atmosphere to control the visible light emission center of the nanophosphors. The intensities of the OH group decreased with the increasing fluorine concentrations. For the specimens annealed in air, the light emission center of the nanophosphor was 615 nm, which was emission from the Eu ion. However, when they were annealed in reduced gas (Ar + 5% H ), a 448 nm light emission center from the Eu ion of FHA was observed. The presence of fluorine in Eu-doped FHA resulted in a significant enhancement of nanophosphor luminescence, which has potential application in light emission and nanomedicine.

Luminescent calcium phosphate bioceramics doped with europium derived from fish industry byproducts

“…This spectral signature is in good agreement with the one reported for Eu 3+ in phosphate matrix . The 5 D 0 → 7 F 4 transition was not investigated in some Eu 3+ ‐doped CaP bioceramics previously studied, while it was reported in others . Our hypothesis is that this peculiar emission centred around 700 nm arises mostly from Eu substituted as dopant in the CaP matrix rather than from the oxide, as this feature is completely different from that reported for europium in Eu 2 O 3 , which generally presents a much weaker 5 D 0 → 7 F 4 (if compared to 5 D 0 → 7 F 2 ) and no relevant signal at 687 nm.…”

“…The 5 D 0 → 7 F 4 transition was not investigated in some Eu 3+ ‐doped CaP bioceramics previously studied, while it was reported in others . Our hypothesis is that this peculiar emission centred around 700 nm arises mostly from Eu substituted as dopant in the CaP matrix rather than from the oxide, as this feature is completely different from that reported for europium in Eu 2 O 3 , which generally presents a much weaker 5 D 0 → 7 F 4 (if compared to 5 D 0 → 7 F 2 ) and no relevant signal at 687 nm. However, it is important to remark that our systems include a mixture of different phases; therefore a definitive attribution of these transitions is extremely difficult due to the inability to analyze each single phases individually.…”

Physicochemical Characterization of Europium-Doped Hydroxyapatite Thin Films with Antifungal Activity

“…and physicochemical characteristics (such as structural affinity to accept various ions as dopants, etc.) [1][2][3][4][5]. In addition, HAp has recently been involved in the development of new drug delivery systems due to its unique properties that can improve the therapeutic effect of drugs [5][6][7].…”

“…[1][2][3][4][5]. In addition, HAp has recently been involved in the development of new drug delivery systems due to its unique properties that can improve the therapeutic effect of drugs [5][6][7]. In the past few years, researchers' attention was captured by the potential luminescent properties gained by HAp after doping with rare earths (RE) ions.…”

“…In the past few years, researchers' attention was captured by the potential luminescent properties gained by HAp after doping with rare earths (RE) ions. The use of RE ions for doping provides important advantages to the host matrix, including the ability to penetrate deep tissue while preserving the luminescence stability and reduced light scattering and photobleaching [5,6,8].…”