A5027216879- Luminescence Properties of Advanced Materials
- Glass properties and applications
- Nuclear materials and radiation effects
- Microwave Dielectric Ceramics Synthesis
- Electronic and Structural Properties of Oxides
- Advanced Condensed Matter Physics
- Ferroelectric and Piezoelectric Materials
- Perovskite Materials and Applications
- Solid-state spectroscopy and crystallography
- Advancements in Solid Oxide Fuel Cells
- Crystal Structures and Properties
- Luminescence and Fluorescent Materials
- Magnetic and transport properties of perovskites and related materials
- Advanced ceramic materials synthesis
- Thermal Expansion and Ionic Conductivity
- Advanced Battery Materials and Technologies
- Radiation Detection and Scintillator Technologies
- Crystallography and molecular interactions
- Advanced NMR Techniques and Applications
- Advanced Photocatalysis Techniques
- Phase Change Materials Research
- Photonic Crystals and Applications
- Geothermal Energy Systems and Applications
- Ammonia Synthesis and Nitrogen Reduction
- Crystallization and Solubility Studies
Guilin University of Technology
2019-2024
Instituto de Ciencia de Materiales de Sevilla
2011-2024
Universidad de Sevilla
2011-2024
Le Studium
2024
Centre Val de Loire
2024
Centre National de la Recherche Scientifique
2017-2022
Centre Européen de la Céramique
2022
Université de Limoges
2022
Conditions Extrêmes et Matériaux Haute Température et Irradiation
2016-2020
Université d'Orléans
2016-2020
The use of RE 2 Si O 7 materials as environmental barrier coatings ( EBC s) and in the sintering process advanced ceramics demands a precise knowledge coefficient thermal expansion . High‐temperature X‐ray diffraction HTXRD ) patterns were collected on different polymorphs, namely A, G, α, β, γ, δ, to determine changes unit cell dimensions. compounds belonging same polymorph showed, qualitatively, very similar parameters behavior with temperature, whereas polymorphs given compound exhibited...
Tetrahedral units can transport oxide anions via interstitial or vacancy defects owing to their great deformation and rotation flexibility. Compared with defects, vacancy-mediated oxide-ion conduction in tetrahedra-based structures is more difficult occurs rarely. The isolated tetrahedral anion Scheelite structure has showed the advantage of conducting oxygen interstitials but vacancies hardly be introduced into promote ion migration. Here we demonstrate that stabilized BiVO4 through Sr2+...
A new bismuth-based halide double perovskite Cs2LiBiCl6 was isolated successfully using solid-state reactions. The crystal structure investigated X-ray diffraction and complemented by 7Li nuclear magnetic resonance spectroscopy, which indicated the highly ordered nature of Li Bi ions in B sublattice perovskite. Compared with Na analogue, more moisture-sensitive has a smaller indirect band gap 3.15(2) eV red-shift luminescence around 612 nm as well stronger intensities at Mn2+ doping....
Homogeneous monoclinic GdPO4 particles composed of three intersecting lance-shaped crystals forming a penetration twin have been synthesized following very restrictive, simple, and fast (10 min) method consisting the hydrothermal reaction gadolinium acetylacetonate with H3PO4 in mixture ethylene glycol water at 180 °C. Slightly increasing amount solvent leads to hexagonal rodlike GdPO4·0.5H2O nanoparticles, whereas variation Gd source, PO4 aging temperature, polyol type gave rise...
Highly transparent glass ceramics, synthesized from a precursor with nominal composition of SiO 2 /ZnO/Ga O 3 /Na O/Cr (65:17:23:5:0.125), were prepared by crystallization. This method enables the synthesis up to 50 wt.‐% size‐controllable Cr 3+ ‐doped ZnGa 4 nanocrystals embedded in an ‐rich matrix after crystallization at 900–1000 °C for 10 min. Rietveld refinements and transmission electron microscopy imaging showed that nanoparticle sizes are ca. 16 33 nm ceramics annealed 900 1000 °C,...
Two new white-light (WL)-emitting phosphors (δ-Gd2Si2O7:Dy and δ-Gd2Si2O7:Eu,Tb) have been synthesized by the sol–gel method. The Gd-Ln3+ (Ln3+= Dy3+, Tb3+, Eu3+) energy-transfer band has used to excite both phosphors, which provides an enhancement of Ln3+ emissions. First, WL was generated from δ-Gd2Si2O7:xDy thanks particular ratio blue yellow emissions observed in all three compositions, had chromatic coordinates x = 0.30, y 0.33 CCT values between 7077 6721 K. decay curves main...
ZnGa2O4:Cr3+, owing to its persistent luminescence properties in the deep red range, is an exceptional material view of foreseen vivo imaging applications. In present work, we report elaboration process and detailed investigations optical nano glass-ceramics composed spinel ZnGa2O4:Cr3+,Yb3+ nanocrystals embedded a transparent, silica rich, glass matrix. The as-prepared materials show good incorporation dopants crystallites leading both Cr3+ Yb3+ emissions. These emissions occur while...
New transparent Ln<sub>1+x</sub>Sr<sub>1−x</sub>Ga<sub>3</sub>O<sub>7+</sub><italic>δ</italic> (Eu/Gd/Tb) melilite ceramics, elaborated by full crystallization from glass, show anionic conductivity (>0.01 S cm<sup>−1</sup> at 700 °C).
Gallate melilite materials have attracted considerable interest as new interstitial oxide ion conducting electrolytes for solid fuel cells more than a decade. However, the preparation of aluminate conductors remains challenge. Here, we show that La1+xCa1–xAl3O7+0.5x (x = 0–0.5) can be prepared via full crystallization from bulk glass process. Rietveld refinements performed combined neutron and synchrotron X-ray powder diffraction (NPD SPD) data reveal multiple defect positions within...
Eu-doped Sr1-x/2Al2-xSixO4 (x = 0.2, 0.4, and 0.5) transparent ceramics have been synthesized by full congruent crystallization from glasses prepared aerodynamic levitation laser-heating method. Structural refinements synchrotron neutron powder diffraction data show that the adopt a 1 × 2 superstructure compared to SrAl2O4 hexagonal polymorph. While observed reflections indicate long-range ordering of Sr vacancies in structure, 29Si 27Al solid-state NMR measurements associated with DFT...
Transparent Sr<italic>RE</italic>Ga<sub>3</sub>O<sub>7</sub> polycrystalline ceramics were prepared from full and congruent glass crystallization. The SrGdGa<sub>3</sub>O<sub>7</sub> material doped with Dy<sup>3+</sup> or codoped Tb<sup>3+</sup>/Eu<sup>3+</sup> exhibits white light emission under UV excitation.
Mixed oxide ion–proton conduction and the cooperative ionic migration mechanism in isolated tetrahedral LaVO 4 by acceptor doping strategies.
High resolution synchrotron powder XRD, 89Y CPMG NMR, and 139La MAS NMR spectroscopy have been applied to eventually draw the phase diagram of La2Si2O7–Y2Si2O7 system. The presents a solid solubility region G-(La,Y)2Si2O7, which extends La0.9Y1.1Si2O7 composition at any temperature this study. Compositions richer in Y show two-phase domains, with G + α T < 1450 °C δ > °C. Y-rich extreme is more complex, showing two solution regions δ- γ-(La,Y)2Si2O7 polymorphs appear increasing content,...
Pure A-La2Si2O7 powder has been synthesized through a spray pyrolysis method followed by calcination at 1100 °C for 15 h. The crystallographic structure, refined from the synchrotron diffraction pattern of sample, showed tetragonal symmetry with space group P41, = 6.83565(1) Å, and c 24.84133(1) Å. 29Si 139La NMR spectra have described here first time in literature could be simulated four Si La resonances, respectively, good agreement presence sites unit cell. same synthesis was successful...
Co-doped hexagonal Sr1-x/2Al2-xSixO4:Eu2+,Dy3+ (0.1 ≤ x 0.5) transparent ceramics have been elaborated by full glass crystallization. The compositions with low SiO2 content (x 0.4) require fast quenching conditions to form glass, i.e. specific elaboration processes such as aerodynamic levitation coupled laser heating, whereas the = 0.5 composition can be prepared on a large scale classic melt-quenching method in commercial furnaces. After single thermal treatment, resulting SrAl2O4-based...
The continuous breaking and reforming of VO 4 tetrahedra in scheelite BiVO is mainly affected by the acceptor dopant size.
Oriented nucleation is proven in three surface crystallizing tectosilicate (SrO/Al<sub>2</sub>O<sub>3</sub> = 1) glasses the system Sr<sub>1−x/2</sub>Al<sub>2−x</sub>Si<sub>x</sub>O<sub>4</sub>.
It is well-known that when an RE2Si2O7 matrix doped with active lanthanide ions, it displays promising luminescent responses for optical applications. The crystalline structure adopted by the silicate as well distribution of dopants among available RE crystallographic sites have important effects on yields these compounds. present study aimed at analyzing structural behavior properties Ho3+-substituted La2Si2O7. Several compositions across La2Si2O7–Ho2Si2O7 system were synthesized using...
Multiple complementary characterization studies indicate that the Sr 2− x Na MgSi 2 O 7−0.5 compositions formed mixed crystalline 7 and Na-containing glassy phases ionic conduction could be contributed by + ions instead of ions.