Русский (РФ) 
English (UK) Journal of Molecular Structure Volume 1149, December 2017, Pages 323-331
Anton Nikolaev, Ilya Kolesnikov, Olga Frank-Kamenetskaya, Maria Kuzmina
Europium concentration effect on сhаracteristics and luminescent properties of hydroxyapatite nanocrystalline powders
Journal of Molecular Structure Volume 1149, December 2017, Pages 323-331
DOI: 10.1016/j.molstruc.2017.08.005
Series of Eu-apatites were synthesized by precipitation from aqueous solutions with the Eu/Ca atomic ratio from 0.5% to 5% at T = 90 ˚C. Resulting precipitates were studied using different experimental techniques including X-ray powder diffraction, infrared and raman spectroscopy, scanning elecrton microscopy, EDX and photoluminescent spectroscopy. Eu-doped Ca-deficit nanosized non-stoichiometric hydroxyapatite with high water content has been obtained throughout the experiment. Europium content in the synthesized apatites reaches 0.24 apfu (Eu/Ca = 2.5%). Relations between Eu content is the solution and precipitate have been established. It was shown that Eu-monacite starts to precipitate as secondary phase at Eu/Ca ratio in starting solution 1% or higher. Maximum luminescence is observed in apatite with ~2% Eu/Ca ratio (which equals to ~0.2 apfu and corresponds to 3% Eu/Ca ratio in the starting solution). As an important and brand-new result, apatite with 2% Eu/Ca ratio can be considered as the most appropriate material for the producing biolabels for luminescent research in medicine and biology.