The study of the influence of pH on the structural and spectroscopic properties of nanocrystalline Eu³⁺ ion-doped yttrium orthovanadate

Abstract

This paper presents an evolution of size and morphology of yttrium orthovanadate, influenced by pH conditions during the synthesis. A thorough research of the spectroscopic properties has been performed. Series...

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

“…This is a natural tendency, and it is natural for the charge transfer to be increased with an increased number of vanadium groups substituted for phosphate groups. Similar results have been presented in different studies, and it seems to strongly correspond to our results [ 63 , 72 , 73 , 75 , 76 ]. The maximum intensity of this peak was noticeable on the spectra corresponding to the samples of Ca 9.9 Eu 0.1 (VO 4 ) 6 (OH) 2 and Ca 9.8 Eu 0.2 (VO 4 ) 6 (OH) 2 and appeared at wavelengths in the range 380–400 nm.…”

“…It is clearly visible for both series of obtained samples as for the compounds: Ca 9.9 Eu 0.1 (PO 4 ) 6−x (VO 4 ) x (OH) 2 and Ca 9.8 Eu 0.2 (PO 4 ) 6−x (VO 4 ) x (OH) 2 (x = 1); the charge transfer O 2 − → Eu 3+ was the most visible and clear characteristic of excitation spectra for europium ions. The more vanadate groups appeared, the more intense the charge transfer O 2 − → V 5+ appeared and the results referred to both series of materials [ 72 , 73 , 75 ]. Moreover, the charge transfer from oxygen to vanadium seems to be slightly shifted toward the highest wavelength number, however, it can be caused by the incorporation of the vanadium groups into the hydroxyapatite framework.…”

Synthesis and Investigation of Physicochemical Properties and Biocompatibility of Phosphate–Vanadate Hydroxyapatite Co-Doped with Tb3+ and Sr2+ Ions

“…Charge–transfer transition can also take place within the hydroxyapatite matrix in the vanadate group (O 2− →V 5+ ; the electron is transferred from the 2p orbital of oxygen to the 3d orbital of vanadium). The peaks originating from O 2− →V 5+ CT should occur in higher wavenumbers than 4f 8 →4f 7 5d 1 transitions of Tb 3+ ions because less energy is required to observe the CT VO 4 transitions ( 1 A 1 → 1 T 1 , 2 T 2 ) (the energy gap between the terms is smaller than in the case of f-d transitions) [ 71 ]. Nevertheless, the positions of the peaks are strongly dependent on the type and nature of the ligands surrounding the V 5+ ion and on the interaction of ions in the crystal lattice [ 22 ].…”