A novel Eu³⁺‐ and self‐activated vanadate phosphor of Ca₄La(VO₄)₃O with oxyvanadate apatite structure

Abstract

Pure and Eu3+‐activated Ca4La(VO4)3O phosphors were prepared via three‐step solid‐phase synthesis. The phase formation and structure were investigated by X‐ray diffraction (XRD) with Rietveld refinements. All the samples crystallized in an apatite‐type structure. The morphological properties were measured via by SEM and EDS measurements. Ca4La(VO4)3O is a new vanadate optical material with a direct band feature and a band energy of 3.1 eV. The undoped Ca4La(VO4)3O phosphor presents self‐activated yellow luminescence from 400 nm to 750 nm with a maximum wavelength of 525 nm originating from VO4 groups. Luminescence characteristics of Ca4La(VO4)3O indicate that the phosphor is not sufficient for practical applications. In Eu3+‐activated Ca4La(VO4)3O, there is an efficient energy transfer from VO4 to Eu3+ ions. The luminescence spectra, concentration quenching, decay curves, color chromaticity, and quantum efficiencies (QE) of Ca4La(VO4)3O:Eu3+ were investigated. The phosphor presents optimal Eu3+ doping concentration of about 20 mol%. The dominant red emission in Ca4La(VO4)3O:Eu3+ is 615 nm from electronic 5D0→7F2 dipole transitions. The quantum efficiency and the luminescence stability of the pure and Eu‐activated Ca4La(VO4)3O were reported. The luminescence was discussed on the structural characteristics.

Investigation of Physicochemical Properties of the Structurally Modified Nanosized Silicate-Substituted Hydroxyapatite Co-Doped with Eu3+ and Sr2+ Ions

“…Moreover, the abnormally strong intensity of the 5 D 0 → 7 F 0 transition has been reported in apatites such as oxyapatite Ca 10 (PO 4 ) 6 O 2 , fluoroapatite Ca 5 (PO 4 ) 3 F, hydroxyapatite Sr 10 (PO 4 ) 6 (OH) 2 , or silicophosphate apatite Sr 5 (PO4) 2 SiO 4 , etc. This intense emission is attributed to the existence of the strong covalence of the Eu 3+ -O 2− bond in the Ca(2) site in the apatite lattice [28][29][30].…”

High pressure exploration in the Li–Ln–V–O system

“…The spectral changes (appearance or disappearance) of Raman modes with pressure gives information about structural modifications of materials and might help to get new structures as done by Grzechnik 19 , LiLa 2 VO 6 , a double perovskite 20 and LaVO 4 doped with several amounts of Li ions 21 . This kind of materials may generate high efficient luminescent properties either by doping with emitters 22,23 or by self-activation of vanadates. 24,25 Starting from the known LiLa 5 O 5 (VO 4 ) 2 19 phase, we have isolated by HP-HT synthesis two new inorganic phases: (1) β-…”

Improvement of self‐activated luminescence from introduced cation disorder in Sr6V2O11

“…Rare earth ion (RE)‐ or self‐activated phosphors have been widely investigated in engineering applications and basic sciences . Self‐activated phosphors present some advantages such as broad emission band, RE free, low sintering temperature, environment‐friendly (sintering in air), low cost, etc.…”

“…Rare earth ion (RE)-or self-activated phosphors have been widely investigated in engineering applications and basic sciences. [1][2][3][4][5][6] Self-activated phosphors present some advantages such as broad emission band, RE free, low sintering temperature, environment-friendly (sintering in air), low cost, etc. For example, self-activated vanadate is efficient luminescence material and has been paid considerable attention on solid-state lighting and display.…”