Browse
Submit Data
Databases
API
Help

Dataset Information

14 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Segregation Engineering in MgO Nanoparticle-Derived Ceramics: The Impact of Calcium and Barium Admixtures on the Microstructure and Light Emission Properties.

ABSTRACT: Nanostructured segregates of alkaline earth oxides exhibit bright photoluminescence emission and great potential as components of earth-abundant inorganic phosphors. We evaluated segregation engineering of Ca²⁺- and Ba²⁺-admixtures in sintered MgO nanocube-derived compacts. Compaction and sintering transform the nanoparticle agglomerates into ceramics with residual porosities of Φ = 24-28%. Size mismatch drives admixture segregation into the intergranular region, where they form thin metal oxide films and inclusions decorating grain boundaries and pores. An important trend in the median grain size evolution of the sintered bodies with d_{Ca(10 at. %)} = 90 nm < d_{Ba(1 at. %)} = 160 nm < d_MgO = 250 nm ∼ d_{Ca(1 at. %)} = 280 nm < d_{Ba(10 at. %)} = 870 nm is rationalized by segregation and interface energies, barriers for ion diffusion, admixture concentration, and the increasing surface basicity of the grains during processing. We outline the potential of admixtures on interface engineering in MgO nanocrystal-derived ceramics and demonstrate that in the sintered compacts, the photoluminescence emission originating from the grain surfaces is retained. Interior parts of the ceramic, which are accessible to molecules from the gas phase, contribute with oxygen partial pressure-dependent intensities to light emission.

SUBMITTER: Schwab T

PROVIDER: S-EPMC8176451 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Impurity Segregation and Nanoparticle Reorganization of Indium Doped MgO Cubes.

Project description:Metal oxide nanocomposites are non-equilibrium solids and promising precursors for functional materials. Annealing of such materials can provide control over impurity segregation and, depending on the level of consolidation, represents a versatile approach to engineer free surfaces, particle-particle interfaces and grain boundaries. Starting with indium-magnesium-oxide nanoparticle powders obtained via injection of an indium organic precursor into the magnesium combustion flame and subsequent particle quenching in argon, we investigated the stability of the trivalent In3+ ions in the host lattice of MgO nanoparticles by determining grain growth, morphology evolution and impurity segregation. The latter process is initiated by vacuum annealing at 873 K and can be tracked at 1173 K on a time scale of minutes. In the first instance the surface segregated indium wets the nanoparticle interfaces. After prolonged annealing indium evaporates and leaves the powder via the gas phase. Resulting MgO nanocubes are devoid of residual indium, regain their high morphological definition and show spectroscopic fingerprints (UV Diffuse Reflectance and Photoluminescence emission) that are characteristic of electronically unperturbed MgO cube corner and edge features. The results of this combined XRD, TEM, and spectroscopy study reveal the parameter window within which control over indium segregation is used to introduce a semiconducting metal oxide component into the intergranular region between insulating MgO nanograins.

| S-EPMC6563704 | biostudies-literature

Unfolding grain size effects in barium titanate ferroelectric ceramics.

Project description:Grain size effects on the physical properties of polycrystalline ferroelectrics have been extensively studied for decades; however there are still major controversies regarding the dependence of the piezoelectric and ferroelectric properties on the grain size. Dense BaTiO3 ceramics with different grain sizes were fabricated by either conventional sintering or spark plasma sintering using micro- and nano-sized powders. The results show that the grain size effect on the dielectric permittivity is nearly independent of the sintering method and starting powder used. A peak in the permittivity is observed in all the ceramics with a grain size near 1??m and can be attributed to a maximum domain wall density and mobility. The piezoelectric coefficient d33 and remnant polarization Pr show diverse grain size effects depending on the particle size of the starting powder and sintering temperature. This suggests that besides domain wall density, other factors such as back fields and point defects, which influence the domain wall mobility, could be responsible for the different grain size dependence observed in the dielectric and piezoelectric/ferroelectric properties. In cases where point defects are not the dominant contributor, the piezoelectric constant d33 and the remnant polarization Pr increase with increasing grain size.

| S-EPMC4423446 | biostudies-literature

Transparent non-cubic laser ceramics with fine microstructure.

Project description:Transparent polycrystalline ceramics with cubic crystal structure have played important roles in a wide variety of solid-state laser applications, whereas for non-cubic structures, single crystal only has been used. For further progress in optical technologies, effective materials beyond the current limitations are necessary. Here we report a new type of non-cubic ceramic laser material that overturns conventional common sense. It is hexagonal Nd-doped fluorapatite (Nd:FAP) ceramics with an optical quality comparable to single crystal while having random crystal orientation. It is composed of ultrafine grains with a loss coefficient of 0.18 cm-1 at a lasing wavelength of 1063 nm, and its laser oscillation was demonstrated. This is the first verification of lasing in randomly oriented non-cubic ceramics. Laser oscillation in the non-cubic ceramics was realized through both advanced liquid-phase nano-powder synthesis technology and highly controlled pulsed-current sintering techniques. Our findings should open new avenues for future solid-state laser and optical applications.

| S-EPMC6635367 | biostudies-literature

Drug-Loaded Biomimetic Ceramics for Tissue Engineering.

Project description:The mimesis of biological systems has been demonstrated to be an adequate approach to obtain tissue engineering scaffolds able to promote cell attachment, proliferation, and differentiation abilities similar to those of autologous tissues. Bioceramics are commonly used for this purpose due to their similarities to the mineral component of hard tissues as bone. Furthermore, biomimetic scaffolds are frequently loaded with diverse therapeutic molecules to enhance their biological performance, leading to final products with advanced functionalities. In this review, we aim to describe the already developed bioceramic-based biomimetic systems for drug loading and local controlled release. We will discuss the mechanisms used for the inclusion of therapeutic molecules on the designed systems, paying special attention to the identification of critical parameters that modulate drug loading and release kinetics on these scaffolds.

| S-EPMC6321415 | biostudies-literature

Local Electronic Structure Perspectives of Nanoparticle Growth: The Case of MgO.

Project description:Herein, we reported nanoparticle growth from the point of view of the local electronic structure by taking MgO as a prototype material. These nanoparticles were obtained from the sol-gel autocombustion process. The precursor formed in this process was annealed for various temperatures ranging from 300 to 1200 °C for 0.5 and 1 h. It was observed that the amorphous phase occurred in the material synthesized at an annealing temperature of 300 °C for 1 h. This phase transformed to crystalline when the annealing temperature was increased to 350 °C. Crystallite size increased with annealing temperature; however, annealing time did not influence the crystallite size. To get deeper insights of modifications occurring at the atomic scale during crystallization growth, the local electronic structure of synthesized materials was investigated by measuring near-edge X-ray absorption fine structure at Mg, O, N, and C K-edges. These results envisaged that Mg2+ ion coordination improved with the increase of annealing temperature. It was also observed that both annealing time and annealing temperature are sensitive to the local electronic structural changes.

| S-EPMC6649258 | biostudies-literature

Dependences of microstructure on electromagnetic interference shielding properties of nano-layered Ti3AlC2 ceramics.

Project description:The microstructure dependent electromagnetic interference (EMI) shielding properties of nano-layered Ti3AlC2 ceramics were presented in this study by comparing the shielding properties of various Ti3AlC2 ceramics with distinct microstructures. Results indicate that Ti3AlC2 ceramics with dense microstructure and coarse grains are more favourable for superior EMI shielding efficiency. High EMI shielding effectiveness over 40?dB at the whole Ku-band frequency range was achieved in Ti3AlC2 ceramics by microstructure optimization, and the high shielding effectiveness were well maintained up to 600?°C. A further investigation reveals that only the absorption loss displays variations upon modifying microstructure by allowing more extensive multiple reflections in coarse layered grains. Moreover, the absorption loss of Ti3AlC2 was found to be much higher than those of highly conductive TiC ceramics without layered structure. These results demonstrate that nano-layered MAX phase ceramics are promising candidates of high-temperature structural EMI shielding materials and provide insightful suggestions for achieving high EMI shielding efficiency in other ceramic-based shielding materials.

| S-EPMC5962584 | biostudies-literature

Core Nanoparticle Engineering for Narrower and More Intense Band-Edge Emission from AgInS2/GaSx Core/Shell Quantum Dots.

Project description:Highly luminescent silver indium sulfide (AgInS2) nanoparticles were synthesized by dropwise injection of a sulfur precursor solution into a cationic metal precursor solution. The two-step reaction including the formation of silver sulfide (Ag2S) nanoparticles as an intermediate and their conversion to AgInS2 nanoparticles, occurred during the dropwise injection. The crystal structure of the AgInS2 nanoparticles differed according to the temperature of the metal precursor solution. Specifically, the tetragonal crystal phase was obtained at 140 °C, and the orthorhombic crystal phase was obtained at 180 °C. Furthermore, when the AgInS2 nanoparticles were coated with a gallium sulfide (GaSx) shell, the nanoparticles with both crystal phases emitted a spectrally narrow luminescence, which originated from the band-edge transition of AgInS2. Tetragonal AgInS2 exhibited narrower band-edge emission (full width at half maximum, FWHM = 32.2 nm) and higher photoluminescence (PL) quantum yield (QY) (49.2%) than those of the orthorhombic AgInS2 nanoparticles (FWHM = 37.8 nm, QY = 33.3%). Additional surface passivation by alkylphosphine resulted in higher PL QY (72.3%) with a narrow spectral shape.

| S-EPMC6955825 | biostudies-literature

Effects of MgO modified ?-TCP nanoparticles on the microstructure and properties of ?-TCP/Mg-Zn-Zr composites.

Project description:The mechanical properties and corrosion resistance of magnesium alloy composites were improved by the addition of MgO surface modified tricalcium phosphate ceramic nanoparticles (m-?-TCP). Mg-3Zn-0.8Zr composites with unmodified (MZZT) and modified (MZZMT) nanoparticles were produced by high shear mixing technology. Effects of MgO m-?-TCP nanoparticles on the microstructure, mechanical properties, electrochemical corrosion properties and cytocompatibility of Mg-Zn-Zr/?-TCP composites were investigated. After hot extrusion deformation and dynamic recrystallization, the grain size of MZZMT was the half size of MZZT and the distribution of m-?-TCP particles in the matrix was more uniform than ?-TCP particles. The yield tensile strength (YTS), ultimate tensile strength (UTS), and corrosion potential (Ecorr) of MZZMT were higher than MZZT; the corrosion current density (Icorr) of MZZMT was lower than MZZT. Cell proliferation of co-cultured MZZMT and MZZT composite samples were roughly the same and the cell number at each time point is higher for MZZMT than for MZZT samples.

| S-EPMC5935024 | biostudies-literature

Ag/MgO Nanoparticles via Gas Aggregation Nanocluster Source for Perovskite Solar Cell Engineering.

Project description:Nanocluster aggregation sources based on magnetron-sputtering represent precise and versatile means to deposit a controlled quantity of metal nanoparticles at selected interfaces. In this work, we exploit this methodology to produce Ag/MgO nanoparticles (NPs) and deposit them on a glass/FTO/TiO2 substrate, which constitutes the mesoscopic front electrode of a monolithic perovskite-based solar cell (PSC). Herein, the Ag NP growth through magnetron sputtering and gas aggregation, subsequently covered with MgO ultrathin layers, is fully characterized in terms of structural and morphological properties while thermal stability and endurance against air-induced oxidation are demonstrated in accordance with PSC manufacturing processes. Finally, once the NP coverage is optimized, the Ag/MgO engineered PSCs demonstrate an overall increase of 5% in terms of device power conversion efficiencies (up to 17.8%).

| S-EPMC8509757 | biostudies-literature

Lattice engineering through nanoparticle-DNA frameworks.

Project description:Advances in self-assembly over the past decade have demonstrated that nano- and microscale particles can be organized into a large diversity of ordered three-dimensional (3D) lattices. However, the ability to generate different desired lattice types from the same set of particles remains challenging. Here, we show that nanoparticles can be assembled into crystalline and open 3D frameworks by connecting them through designed DNA-based polyhedral frames. The geometrical shapes of the frames, combined with the DNA-assisted binding properties of their vertices, facilitate the well-defined topological connections between particles in accordance with frame geometry. With this strategy, different crystallographic lattices using the same particles can be assembled by introduction of the corresponding DNA polyhedral frames. This approach should facilitate the rational assembly of nanoscale lattices through the design of the unit cell.

| S-EPMC5282967 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data