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Records |
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Author |
Pop, N.; Pralong, V.; Caignaert, V.; Colin, J.F.; Malo, S.; Van Tendeloo, G.; Raveau, B. |
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Title |
Topotactic transformation of the cationic conductor Li4Mo5O17 into a rock salt type oxide Li12Mo5O17 |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
21 |
Issue |
14 |
Pages |
3242-3250 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Intercalation of lithium in the ribbon structure Li4Mo5O17 has been achieved, using both electrochemistry and soft chemistry. The ab initio structure determination of the ¡°Mo−O¡± framework of Li12Mo5O17 shows that the [Mo5O17]¡Þ ribbons keep the same arrangement of edge sharing MoO6 octahedra and the same orientation as in the parent structure but that a topotactic antidistortion of the ribbons appears, as a result of the larger size of Mo4+ in ¡°Li12¡± compared to Mo6+ in ¡°Li4¡±. On the basis of bond valence calculations, it is observed that 12 octahedral sites are available for Li+ in the new structure so that an ordered hypothetical rock salt type structure can be proposed for Li12Mo5O17. After the first Li insertion, a stable reversible capacity of 100 mA¡¤h/g is maintained after 20 cycles. A complete structural reversibility leading back to the ribbon type Li4Mo5O17 structure is obtained using a very low rate of C/100. The exploration of the Li mobility in those oxides shows that Li4Mo5O17 is a cationic conductor with ¦Ò = 10−3.5 S/cm at 500 ¡ãC and Ea = 0.35 eV. |
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Place of Publication |
Washington, D.C. |
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Wos |
000268174400032 |
Publication Date |
2009-06-24 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
18 |
Open Access |
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Notes |
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Approved |
Most recent IF: 9.466; 2009 IF: 5.368 |
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Call Number |
UA @ lucian @ c:irua:78285 |
Serial |
3682 |
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Permanent link to this record |
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Author |
Pimenta, V.; Sathiya, M.; Batuk, D.; Abakumov, A.M.; Giaume, D.; Cassaignon, S.; Larcher, D.; Tarascon, J.-M. |
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Title |
Synthesis of Li-Rich NMC : a comprehensive study |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
29 |
Issue |
23 |
Pages |
9923-9936 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
<script type='text/javascript'>document.write(unpmarked('Li-rich NMC are considered nowadays as one of the most promising candidates for high energy density cathodes. One significant challenge is nested in adjusting their synthesis conditions to reach optimum electrochemical performance, but no consensus has been reached yet on the ideal synthesis protocol. Herein, we revisited the elaboration of Li-rich NMC electrodes by focusing on the science involved through each synthesis steps using carbonate Ni0.1625Mn0.675Co0.1625CO3 precursor coprecipitation combined with solid state synthesis. We demonstrated the effect of precursors concentration on the kinetics of the precipitation reaction and provided clues to obtain spherically agglomerated NMC carbonates of different sizes. Moreover, we highlighted the strong impact of the Li2CO3/NMC carbonate ratio on the morphology and particles size of Li-rich NMC and subsequently on their electrochemical performance. Ratio of 1.35 was found to reproducibly give the best performance with namely a first discharge capacity of 269 mAh g(-1) and capacity retention of 89.6% after 100 cycles. We hope that our results, which reveal how particle size, morphology, and phase composition affect the materials electrochemical performance, will help in reconciling literature data while providing valuable fundamental information for up scaling approaches.')); |
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Corporate Author |
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Thesis |
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Publisher |
American Chemical Society |
Place of Publication |
Washington, D.C |
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Language |
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Wos |
000418206600010 |
Publication Date |
2017-11-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
23 |
Open Access |
Not_Open_Access |
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Notes |
; The authors acknowledge the French Research Network on Electrochemical Energy Storage (RS2E). V.P and J.-M.T. acknowledges funding from the European Research Council (ERC) (FP/2014)/ERC Grant-Project 670116-ARPEMA. The authors are thankful to Dr. G. Rousse for the help on Rietveld refinements. ; |
Approved |
Most recent IF: 9.466 |
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Call Number |
UA @ lucian @ c:irua:148530 |
Serial |
4899 |
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Permanent link to this record |
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Author |
Pietra, F.; van Dijk-Moes, R.J.A.; Ke, X.; Bals, S.; Van Tendeloo, G.; de Mello Donega, C.; Vanmaekelbergh, D. |
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Title |
Synthesis of highly luminescent silica-coated CdSe/CdS nanorods |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
25 |
Issue |
17 |
Pages |
3427-3434 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
CdSe(core)/CdS(shell) nanorods (NRs) have been extensively investigated for their unique optical properties, such as high photoluminescence (PL) quantum efficiency (QE) and polarized light emission. The incorporation of these NRs in silica (SiO2) is of high interest, since this renders them processable in polar solvents while increasing their photochemical stability, which would be beneficial for their application in LEDs and as biolabels. We report the synthesis of highly luminescent silica-coated CdSe/CdS NRs, by using the reverse micelle method. The mechanism for the encapsulation of the NRs in silica is unravelled and shown to be strongly influenced by the NR shape and its asymmetry. This is attributed to both the different morphology and the different crystallographic nature of the facets terminating the opposite tips of the NRs. These results lead to the formation of a novel class of NR architectures, whose symmetry can be controlled by tuning the degree of coverage of the silica shell. Interestingly, the encapsulation of the NRs in silica leads to a remarkable increase in their photostability, while preserving their optical properties. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000330097900004 |
Publication Date |
2013-08-13 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
46 |
Open Access |
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Notes |
262348 ESMI; 246791 COUNTATOMS; Hercules |
Approved |
Most recent IF: 9.466; 2013 IF: 8.535 |
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Call Number |
UA @ lucian @ c:irua:110037 |
Serial |
3456 |
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Permanent link to this record |
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Author |
Peters, J.L.; van den Bos, K.H.W.; Van Aert, S.; Goris, B.; Bals, S.; Vanmaekelbergh, D. |
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Title |
Ligand-Induced Shape Transformation of PbSe Nanocrystals |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
29 |
Issue |
29 |
Pages |
4122-4128 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
We present a study of the relation between the surface chemistry and nanocrystal shape of PbSe nanocrystals with a variable Pb-to-Se stoichiometry and density of oleate ligands. The oleate ligand density and binding configuration are monitored by nuclear magnetic resonance and Fourier transform infrared absorbance spectroscopy, allowing us to quantify the number of surface-attached ligands per NC and the nature of the surface−Pb−oleate configuration. The three-dimensional shape of the PbSe nanocrystals is obtained from high-angle annular dark field scanning transmission electron microscopy combined with an atom counting method. We show that the enhanced oleate capping results in a stabilization and extension of the {111} facets, and a crystal shape transformation from a truncated nanocube to a truncated octahedron. |
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Corporate Author |
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Thesis |
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Place of Publication |
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Language |
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Wos |
000401221700034 |
Publication Date |
2017-05-09 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
45 |
Open Access |
OpenAccess |
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Notes |
D.V. acknowledges the European Research Council, ERC advanced grant, Project 692691-First Step, for financial support. We also acknowledge the Dutch FOM programme “Designing Dirac carriers in honeycomb semiconductor superlattices” (FOM Program 152) for financial support. The authors gratefully acknowledge funding from the Research Foundation Flanders (G.036915, G.037413, and funding of a Ph.D. research grant to K.H.W.v.d.B. and a postdoctoral grant to B.G.). S.B. acknowledges the European Research Council, ERC Grant 335078-Colouratom. (ROMEO:white; preprint:; postprint:restricted 12 months embargo; pdfversion:cannot); ECAS_Sara |
Approved |
Most recent IF: 9.466 |
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Call Number |
EMAT @ emat @ c:irua:143750 c:irua:142983UA @ admin @ c:irua:143750 |
Serial |
4571 |
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Permanent link to this record |
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Author |
Peters, J.L.; Altantzis, T.; Lobato, I.; Jazi, M.A.; van Overbeek, C.; Bals, S.; Vanmaekelbergh, D.; Sinai, S.B. |
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Title |
Mono- and Multilayer Silicene-Type Honeycomb Lattices by Oriented Attachment of PbSe Nanocrystals: Synthesis, Structural Characterization, and Analysis of the Disorder |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
30 |
Issue |
30 |
Pages |
4831-4837 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Nanocrystal (NC) solids are commonly prepared from nonpolar organic NC suspensions. In many cases, the capping on the NC surface is preserved and forms a barrier between the NCs. More recently, superstructures with crystalline connections between the NCs, implying the removal of the capping, have been reported, too. Here, we present large-scale uniform superstructures of attached PbSe NCs with a silicene-type honeycomb geometry, resulting from solvent evaporation under nearly reversible conditions. We also prepared multilayered silicene honeycomb structures by using larger amounts of PbSe NCs. We show that the two-dimensional silicene superstructures can be seen as a crystallographic slice from a 3-D simple cubic structure. We describe the disorder in the silicene lattices in terms of the nanocrystals position and their atomic alignment. The silicene honeycomb sheets are large enough to be used in transistors and optoelectronic devices. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000440105500042 |
Publication Date |
2018-07-24 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
33 |
Open Access |
OpenAccess |
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Notes |
The authors acknowledge funding from the European Commission (Grant EUSMI 731019). S.B. acknowledges funding from the European Research Council (Grant 335078 COLOURATOM). T.A. acknowledges a postdoctoral grant from the Research Foundation Flanders (FWO). The authors acknowledge financial support from the European Commission under the Horizon 2020 Programme by means of the Grant Agreement No. 731019 EUSMI. (ROMEO:white; preprint:; postprint:restricted 12 months embargo; pdfversion:cannot); ecas_sara |
Approved |
Most recent IF: 9.466 |
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Call Number |
EMAT @ emat @c:irua:152997UA @ admin @ c:irua:152997 |
Serial |
5011 |
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Permanent link to this record |
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Author |
Perez, A.J.; Batuk, D.; Saubanère, M.; Rousse, G.; Foix, D.; Mc Calla, E.; J. Berg, E.; Dugas, R.; van den Bos, K. H. W.; Doublet, M.-L.; Gonbeau, D.; Abakumov, A.M.; Van Tendeloo, G.; Tarascon, J.-M. |
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Title |
Strong oxygen participation in the redox governing the structural and electrochemical properties of Na-rich layered oxide Na2IrO3 |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
28 |
Issue |
28 |
Pages |
8278-8288 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The recent revival of the Na-ion battery concept has prompted intense activities in the search for new Na-based layered oxide positive electrodes. The largest capacity to date was obtained for a Na-deficient layered oxide that relies on cationic redox processes only. To go beyond this limit, we decided to chemically manipulate these Na-based layered compounds in a way to trigger the participation of the anionic network. We herein report the electrochemical properties of a Na-rich phase Na2IrO3, which can reversibly cycle 1.5 Na+ per formula unit while not suffering from oxygen release nor cationic migrations. Such large capacities, as deduced by complementary XPS, X-ray/neutron diffraction and transmission electron microscopy measurements, arise from cumulative cationic and anionic redox processes occurring simultaneously at potentials as low as 3.0 V. The inability to remove more than 1.5 Na+ is rooted in the formation of an O1-type phase having highly stabilized Na sites as confirmed by DFT calculations, which could rationalize as well the competing metal/oxygen redox processes in Na2IrO3. This work will help to define the most fertile directions in the search for novel high energy Na-rich materials based on more sustainable elements than Ir. |
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Corporate Author |
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Publisher |
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Place of Publication |
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Language |
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Wos |
000388914500021 |
Publication Date |
2016-10-17 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
45 |
Open Access |
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Notes |
The authors thank Montse Casas-Cabanas and Marine Reynaud for discussions about the FAULTS program, Sandra Van Aert for her great help in guiding us towards the use of the statistical parameter estimation method for establishing the O-O histogram, and Thomas Hansen and Vladimir Pomjakushin for their precious help in neutron diffraction experiments. This work is based on experiments performed at the Swiss spallation neutron source SINQ, Paul Scherrer Institute, Villigen, Switzerland, and at Institut Laue Langevin, Grenoble, France. Use of the 11-BM mail service of the APS at Argonne National Laboratory was supported by the U.S. department of Energy under contract No. DE-AC02-06CH11357 and is greatly acknowledged. |
Approved |
Most recent IF: 9.466 |
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Call Number |
EMAT @ emat @ c:irua:135994 |
Serial |
4287 |
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Permanent link to this record |
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Author |
Pelloquin, D.; Hadermann, J.; Giot, M.; Caignaert, V.; Michel, C.; Hervieu, M.; Raveau, B. |
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Title |
Novel, oxygen-deficient n=3 RP-member Sr3NdFe3O9-\delta and its topotactic derivatives |
Type |
A1 Journal article |
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Year |
2004 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
16 |
Issue |
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Pages |
1715-1724 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000221345000019 |
Publication Date |
2004-04-27 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
24 |
Open Access |
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Notes |
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Approved |
Most recent IF: 9.466; 2004 IF: 4.103 |
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Call Number |
UA @ lucian @ c:irua:47318 |
Serial |
2381 |
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Permanent link to this record |
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Author |
Pearce, P.E.; Rousse, G.; Karakulina, O.M.; Hadermann, J.; Van Tendeloo, G.; Foix, D.; Fauth, F.; Abakumov, A.M.; Tarascon, J.-M. |
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Title |
β-Na1.7IrO3: A Tridimensional Na-Ion Insertion Material with a Redox Active Oxygen Network |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
30 |
Issue |
10 |
Pages |
3285-3293 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The revival of the Na-ion battery concept has prompted an intense search for new high capacity Na-based positive electrodes. Recently, emphasis has been placed on manipulating Na-based layered compounds to trigger the participation of the anionic network. We further explored this direction and show the feasibility of achieving anionic-redox activity in three-dimensional Na-based compounds. A new 3D β-Na1.7IrO3 phase was synthesized in a two-step process, which involves first the electrochemical removal of Li from β-Li2IrO3 to produce β-IrO3, which is subsequently reduced by electrochemical Na insertion. We show that β-Na1.7IrO3 can reversibly uptake nearly 1.3 Na+ per formula unit through an uneven voltage profile characterized by the presence of four plateaus related to structural transitions. Surprisingly, the β-Na1.7IrO3 phase was found to be stable up to 600 °C, while it could not be directly synthesized via conventional synthetic methods. Although these Na-based iridate phases are of limited practical interest, they help to understand how introducing highly polarizable guest ions (Na+) into host rocksalt-derived oxide structures affects the anionic redox mechanism. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Language |
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Wos |
000433403800014 |
Publication Date |
2018-05-22 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
6 |
Open Access |
OpenAccess |
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Notes |
The authors thank A. Perez for fruitful discussions and his valuable help in synchrotron XRD experiment and Matthieu Courty for carrying out the DSC measurements. The authors also greatly thank Matthieu Saubanère and Marie-Liesse Doublet for valuable discussions on theoretical aspects of this work. This work is based on experiments performed on the Materials Science and Powder Diffraction Beamline at ALBA synchrotron (Proposal 2016091814), Cerdanyola del Vallès, E- 08290 Barcelona, Spain. J.-M.T. acknowledges funding from the European Research Council (ERC) (FP/2014)/ERC Grant- Project 670116-ARPEMA. G.R. acknowledges funding from ANR DeliRedox. O.M.K., J.H., and A.M.A. are grateful to FWO Vlaanderen for financial support under Grant G040116N. |
Approved |
Most recent IF: 9.466 |
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Call Number |
EMAT @ emat @c:irua:152048 |
Serial |
4996 |
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Permanent link to this record |
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Author |
Parsons, T.G.; d' Hondt, H.; Hadermann, J.; Hayward, M.A. |
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Title |
Synthesis and structural characterization of La1-xAxMnO2.5 (A = Ba, Sr, Ca) phases: mapping the variants of the brownmillerite structure |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
21 |
Issue |
22 |
Pages |
5527-5538 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Analysis of the structural parameters of phases that adopt brownmillerite-type structures suggests the distribution of the different complex ordering schemes adopted within this structure type can be rationalized by considering both the size of the separation between the tetrahedral layers and the tetrahedral chain distortion angle. A systematic study using structural data obtained from La1−xAxMnO2,5 (A = Ba, Sr, Ca,) phases, prepared by the topotactic reduction of the analogous La1−xAxMnO3 perovskite phases, was performed to investigate this relationship. By manipulating the A-cation composition, both the tetrahedral layer separation and tetrahedral chain distortion angle in the La1−xAxMnO2,5 phases were controlled and from the data obtained a ¡°structure map¡± of the different brownmillerite variants was plotted as a function of these structural parameters. This map has been extended to include a wide range of reported brownmillerite phases showing the structural ideas presented are widely applicable. The complete structural characterization of La1−xAxMnO2,5 0.1 ¡Ü x ¡Ü 0.33, A = Ba; 0.15 ¡Ü x ¡Ü 0.5 A = Sr, and 0.22 ¡Ü x ¡Ü 0.5 A = Ca is described and includes compositions which exhibit complex intralayer ordered structures and Mn2+/Mn3+ charge ordering. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000271756400021 |
Publication Date |
2009-10-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
60 |
Open Access |
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Notes |
Iap Vi |
Approved |
Most recent IF: 9.466; 2009 IF: 5.368 |
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Call Number |
UA @ lucian @ c:irua:79935 |
Serial |
3435 |
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Permanent link to this record |
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Author |
Panin, R.V.; Shpanchenko, R.V.; Mironov, A.V.; Velikodny, Y.A.; Antipov, E.V.; Hadermann, J.; Tarnopolsky, V.A.; Yaroslavtsev, A.B.; Kaul, E.E.; Geibel, C. |
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Title |
Crystal structure, polymorphism, and properties of the new vanadyl phosphate Na4VO(PO4)2 |
Type |
A1 Journal article |
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Year |
2004 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
16 |
Issue |
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Pages |
1048-1055 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000220304100014 |
Publication Date |
2004-03-16 |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
11 |
Open Access |
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Notes |
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Approved |
Most recent IF: 9.466; 2004 IF: 4.103 |
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Call Number |
UA @ lucian @ c:irua:43873 |
Serial |
577 |
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Permanent link to this record |
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Author |
Mulder, J.T.T.; Jenkinson, K.; Toso, S.; Prato, M.; Evers, W.H.H.; Bals, S.; Manna, L.; Houtepen, A.J.J. |
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Title |
Nucleation and growth of bipyramidal Yb:LiYF₄ nanocrystals : growing up in a hot environment |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Chemistry of materials |
Abbreviated Journal |
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Volume |
35 |
Issue |
14 |
Pages |
5311-5321 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Lanthanide-doped LiYF4 (Ln:YLF) is commonlyused fora broad variety of optical applications, such as lasing, photon upconversionand optical refrigeration. When synthesized as nanocrystals (NCs),this material is also of interest for biological applications andfundamental physical studies. Until now, it was unclear how Ln:YLFNCs grow from their ionic precursors into tetragonal NCs with a well-defined,bipyramidal shape and uniform dopant distribution. Here, we studythe nucleation and growth of ytterbium-doped LiYF4 (Yb:YLF),as a template for general Ln:YLF NC syntheses. We show that the formationof bipyramidal Yb:YLF NCs is a multistep process starting with theformation of amorphous Yb:YLF spheres. Over time, these spheres growvia Ostwald ripening and crystallize, resulting in bipyramidal Yb:YLFNCs. We further show that prolonged heating of the NCs results inthe degradation of the NCs, observed by the presence of large LiFcubes and small, irregular Yb:YLF NCs. Due to the similarity in chemicalnature of all lanthanide ions our work sheds light on the formationstages of Ln:YLF NCs in general. |
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Wos |
001021474500001 |
Publication Date |
2023-07-03 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756; 1520-5002 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
8.6 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
This project has received funding from the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 766900 (Testing the large-scale limit of quantum mechanics). The authors thank Niranjan Saikumar for proof reading the manuscript. |
Approved |
Most recent IF: 8.6; 2023 IF: 9.466 |
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Call Number |
UA @ admin @ c:irua:197787 |
Serial |
8907 |
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Permanent link to this record |
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Author |
Morozov, V.A.; Lazoryak, B.I.; Shmurak, S.Z.; Kiselev, A.P.; Lebedev, O.I.; Gauquelin, N.; Verbeeck, J.; Hadermann, J.; Van Tendeloo, G. |
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Title |
Influence of the structure on the properties of NaxEuy(MoO4)z red phosphors |
Type |
A1 Journal article |
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Year |
2014 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
26 |
Issue |
10 |
Pages |
3238-3248 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Scheelite related compounds (A',A '')(n)[(B',B '')O-4](m) with B', B '' = W and/or Mo are promising new materials for red phosphors in pc-WLEDs (phosphor-converted white-light-emitting-diode) and solid-state lasers. Cation substitution in CaMoO4 of Ca2+ by the combination of Na+ and Eu3+, with the creation of A cation vacancies, has been investigated as a factor for controlling the scheelite-type structure and the luminescent properties. Na5Eu(MoO4)(4) and NaxEu(2-x)/33+square(2-x)/3MoO4 (0.138 <= x <= 0.5) phases with a scheelite-type structure were synthesized by the solid state method; their structural characteristics were investigated using transmission electron microscopy. Contrary to powder synchrotron X-ray diffraction before, the study by electron diffraction and high resolution transmission electron microscopy in this paper revealed that Na0.286Eu0.571MoO4 has a (3 + 2)D incommensurately modulated structure and that (3 + 2)D incommensurately modulated domains are present in Na0.200Eu0.600MoO4. It also confirmed the (3 + 1)D incommensurately modulated character of Na(0.138)Eu(0.621)Mo04. The luminescent properties of all phases under near-ultraviolet (n-UV) light have been investigated. The excitation spectra of these phosphors show the strongest absorption at about 395 nm, which matches well with the commercially available n-UV-emitting GaN-based LED chip. The emission spectra indicate an intense red emission due to the D-5(0) -> F-7(2) transition of Eu3+, with local minima in the intensity at Na0.286Eu0.571MoO4 and Na0.200Eu0.600MoO4 for similar to 613 nm and similar to 616 nm bands. The phosphor Na5Eu(MoO4)(4) shows the brightest red light emission among the phosphors in the Na2MoO4-Eu2/3MoO4 system and the maximum luminescence intensity of Na5Eu(MoO4)(4) (lambda(ex) = 395 nm) in the D-5(0) -> F-7(2) transition region is close to that of the commercially used red phosphor YVO4:Eu3+ (lambda(ex) = 326 nm). Electron energy loss spectroscopy measurements revealed the influence of the structure and Na/Eu cation distribution on the number and positions of bands in the UV-optical-infrared regions of the EELS spectrum. |
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Wos |
000336637000028 |
Publication Date |
2014-05-01 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
53 |
Open Access |
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Notes |
Fwo G039211n; Fwo G004413n; 278510 Vortex ECASJO_; |
Approved |
Most recent IF: 9.466; 2014 IF: 8.354 |
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Call Number |
UA @ lucian @ c:irua:117765UA @ admin @ c:irua:117765 |
Serial |
1652 |
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Permanent link to this record |
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Author |
Morozov, V.A.; Batuk, D.; Batuk, M.; Basovich, O.M.; Khaikina, E.G.; Deyneko, D.V.; Lazoryak, B.I.; Leonidov, I.I.; Abakumov, A.M.; Hadermann, J. |
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Title |
Luminescence Property Upgrading via the Structure and Cation Changing in AgxEu(2–x)/3WO4and AgxGd(2–x)/3–0.3Eu0.3WO4 |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
29 |
Issue |
20 |
Pages |
8811-8823 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The creation and ordering of A-cation vacancies and the effect of cation substitutions in the scheelite-type framework are investigated as a factor for controlling the scheelite-type structure and luminescence properties. AgxEu3+(2−x)/3□(1−2x)/3WO4 and AgxGd(2−x)/3−0.3Eu3+0.3□(1−2x)/3WO4 (x = 0.5−0) scheelite-type phases were synthesized by a solid state method, and their structures were investigated using a combination of transmission electron microscopy techniques and powder synchrotron X-ray diffraction. Transmission electron microscopy also revealed the (3 + 1)D incommensurately modulated character of AgxEu3+(2−x)/3□(1−2x)/3WO4 (x = 0.286, 0.2) phases. The crystal structures of the scheelite-based AgxEu3+(2−x)/3□(1−2x)/3WO4 (x = 0.5, 0.286, 0.2) red phosphors have been refined from high resolution synchrotron powder X-ray diffraction data. The luminescence properties of all phases under near-ultraviolet (n-UV) light have been investigated. The excitation spectra of AgxEu3+(2−x)/3□(1−2x)/3WO4 (x = 0.5, 0.286,0.2) phosphors show the strongest absorption at 395 nm, which matches well with the commercially available n-UV-emitting GaN-based LED chip. The excitation spectra of the Eu2/3□1/3WO4 and Gd0.367Eu0.30□1/3WO4 phases exhibit the highest contribution of the charge transfer band at 250 nm and thus the most efficient energy transfer mechanism between the host and the luminescent ion as compared to direct excitation. The emission spectra of all samples indicate an intense red emission due to the 5D0 → 7F2 transition of Eu3+. Concentration dependence of the 5D0 → 7F2 emission for AgxEu(2−x)/3□(1−2x)/3WO4 samples differs from the same dependence for the earlier studied NaxEu3+(2−x)/3□(1−2x)/3MoO4 (0 ≤ x ≤ 0.5) phases. The intensity of the 5D0 → 7F2 emission is reduced almost 7 times with decreasing x from 0.5 to 0, but it practically does not change in the range from x = 0.286 to x = 0.200. The emission spectra of Gd-containing samples show a completely different trend as compared to only Eu-containing samples. The Eu3+ emission under excitation of Eu3+(5L6) level (λex = 395 nm) increases more than 2.5 times with the increasing Gd3+ concentration from 0.2 (x = 0.5) to 0.3 (x = 0.2) in the AgxGd(2−x)/3−0.3Eu3+0.3□(1−2x)/3WO4, after which it remains almost constant for higher Gd3+ concentrations. |
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Wos |
000413884900028 |
Publication Date |
2017-10-24 |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
7 |
Open Access |
Not_Open_Access |
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Notes |
This research was supported by FWO (project G039211N), Flanders Research Foundation. V.A.M. is grateful for financial support of the Russian Foundation for Basic Research (Grant 15-03-07741). E.G.K. and O.M.B. are grateful for financial support of the Russian Foundation for Basic Research (Grants 13-03-01020 and 16-03-00510). D.V.D. is grateful for financial support of the Russian Foundation for Basic Research (Grant 16-33-00197) and the Foundation of the President of the Russian Federation (Grant MK-7926.2016.5.). We are grateful to the ESRF for granting the beamtime. Experimental support of Andy Fitch at the ID31 beamline of ESRF is kindly acknowledged. |
Approved |
Most recent IF: 9.466 |
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Call Number |
EMAT @ emat @c:irua:147241 |
Serial |
4768 |
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Permanent link to this record |
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Author |
Morozov, V.A.; Arakcheeva, A.V.; Pattison, P.; Meert, K.W.; Smet, P.F.; Poelman, D.; Gauquelin, N.; Verbeeck, J.; Abakumov, A.M.; Hadermann, J. |
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Title |
KEu(MoO4)2 : polymorphism, structures, and luminescent properties |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
27 |
Issue |
27 |
Pages |
5519-5530 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
In this paper, with the example of two different polymorphs of KEu(MoO4)2, the influence of the ordering of the A-cations on the luminescent properties in scheelite related compounds (A′,A″)n[(B′,B″)O4]m is investigated. The polymorphs were synthesized using a solid state method. The study confirmed the existence of only two polymorphic forms at annealing temperature range 9231203 K and ambient pressure: a low temperature anorthic α-phase and a monoclinic high temperature β-phase with an incommensurately modulated structure. The structures of both polymorphs were solved using transmission electron microscopy and refined from synchrotron powder X-ray diffraction data. The monoclinic β-KEu(MoO4)2 has a (3+1)-dimensional incommensurately modulated structure (superspace group I2/b(αβ0)00, a = 5.52645(4) Å, b = 5.28277(4) Å, c = 11.73797(8) Å, γ = 91.2189(4)o, q = 0.56821(2)a*0.12388(3)b*), whereas the anorthic α-phase is (3+1)-dimensional commensurately modulated (superspace group I1̅(αβγ)0, a = 5.58727(22) Å, b = 5.29188(18)Å, c = 11.7120(4) Å, α = 90.485(3)o, β = 88.074(3)o, γ = 91.0270(23)o, q = 1/2a* + 1/2c*). In both cases the modulation arises due to Eu/K cation ordering at the A site: the formation of a 2-dimensional Eu3+ network is characteristic for the α-phase, while a 3-dimensional Eu3+-framework is observed for the β-phase structure. The luminescent properties of KEu(MoO4)2 samples prepared under different annealing conditions were measured, and the relation between their optical properties and their structures is discussed. |
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Wos |
000360323700011 |
Publication Date |
2015-07-29 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
26 |
Open Access |
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Notes |
278510 Vortex; Fwo G039211n; G004413n ECASJO_; |
Approved |
Most recent IF: 9.466; 2015 IF: 8.354 |
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Call Number |
c:irua:127244 |
Serial |
3537 |
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Permanent link to this record |
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Author |
Morozov, V.A.; Arakcheeva, A.V.; Chapuis, G.; Guiblin, N.; Rossell, M.D.; Van Tendeloo, G. |
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Title |
KNd(MoO4)2: a new incommensurate modulated structure in the scheelite family |
Type |
A1 Journal article |
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Year |
2006 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
18 |
Issue |
17 |
Pages |
4075-4082 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Place of Publication |
Washington, D.C. |
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Wos |
000239758300022 |
Publication Date |
2006-07-28 |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
46 |
Open Access |
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Notes |
Iap V-1 |
Approved |
Most recent IF: 9.466; 2006 IF: 5.104 |
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Call Number |
UA @ lucian @ c:irua:60688 |
Serial |
3538 |
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Permanent link to this record |
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Author |
Morozov, V.; Deyneko, D.; Basoyich, O.; Khaikina, E.G.; Spassky, D.; Morozov, A.; Chernyshev, V.; Abakumov, A.; Hadermann, J. |
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Title |
Incommensurately modulated structures and luminescence properties of the AgxSm(2-x)/3WO4 (x=0.286, 0.2) scheelites as thermographic phosphors |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
30 |
Issue |
14 |
Pages |
4788-4798 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Ag+ for Sm3+ substitution in the scheelite-type AgxSm(2-x)/3 square(1-2x)/3WO4 tungstates has been investigated for its influence on the cation-vacancy ordering and luminescence properties. A solid state method was used to synthesize the x = 0.286 and x = 0.2 compounds, which exhibited (3 + 1)D incommensurately modulated structures in the transmission electron microscopy study. Their structures were refined using high resolution synchrotron powder X-ray diffraction data. Under near-ultraviolet light, both compounds show the characteristic emission lines for (4)G(5/2) -> H-6(J) (J = 5/2, 7/2, 9/2, and 11/2) transitions of the Sm3+ ions in the range 550-720 nm, with the J = 9/2 transition at the similar to 648 nm region being dominant for all photoluminescence spectra. The intensities of the (4)G(5/2) -> H-6(9/2) and (4)G(5/2) -> H-6(7/2) bands have different temperature dependencies. The emission intensity ratios (R) for these bands vary reproducibly with temperature, allowing the use of these materials as thermographic phosphors. |
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Publisher |
American Chemical Society |
Place of Publication |
Washington, D.C |
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Wos |
000440105500037 |
Publication Date |
2018-06-21 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
2 |
Open Access |
Not_Open_Access |
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Notes |
; This research was supported by FWO (Project G039211N), Flanders Research Foundation. The research was carried out within the state assignment of FASO of Russia (Themes No. 0339-2016-0007). V.M. thanks the Russian Foundation for Basic Research (Grant 18-03-00611) for financial support. E.G.K. and O.B. acknowledge financial support from the Russian Foundation for Basic Research (Grant 16-03-00510). D.D. thanks the Foundation of the Russian Federation President (Grant MK-3502.2018.5) for financial support. We are grateful to the ESRF for granting the beamtime. V.C. is grateful for the financial support of the Russian Ministry of Science and Education (Project No. RFMEFI61616X0069). We are grateful to the ESRF for the access to ID22 station (experiment MA-3313). ; |
Approved |
Most recent IF: 9.466 |
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Call Number |
UA @ lucian @ c:irua:153156 |
Serial |
5107 |
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Permanent link to this record |
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Author |
Minjauw, M.M.; Solano, E.; Sree, S.P.; Asapu, R.; Van Daele, M.; Ramachandran, R.K.; Heremans, G.; Verbruggen, S.W.; Lenaerts, S.; Martens, J.A.; Detavernier, C.; Dendooven, J. |
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Title |
Plasma-enhanced atomic layer deposition of silver using Ag(fod)(PEt3) and NH3-plasma |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
29 |
Issue |
17 |
Pages |
7114-7121 |
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Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
A plasma-enhanced atomic layer deposition (ALD) process using the Ag(fod)(PEt3) precursor [(triethylphosphine)(6,6,7,7,8,8,8-heptafluoro-2,2-dimethy1-3,5-octanedionate)silver(I)] in combination with NH3-plasma is reported. The steady growth rate of the reported process (0.24 +/- 0.03 nm/cycle) was found to be 6 times larger than that of the previously reported Ag ALD process based on the same precursor in combination with H-2-plasma (0.04 +/- 0.02 nm/cycle). The ALD characteristics of the H-2-plasma and NH3-plasma processes were verified. The deposited Ag films were polycrystalline face-centered cubic Ag for both processes. The film morphology was investigated by ex situ scanning electron microscopy and grazing-incidence small-angle X-ray scattering, and it was found that films grown with the NH3-plasma process exhibit a much higher particle areal density and smaller particle sizes on oxide substrates compared to those deposited using the H-2-plasma process. This control over morphology of the deposited Ag is important for applications in catalysis and plasmonics. While films grown with the H-2-plasma process had oxygen impurities (similar to 9 atom %) in the bulk, the main impurity for the NH3-plasma process was nitrogen (similar to 7 atom %). In situ Fourier transform infrared spectroscopy experiments suggest that these nitrogen impurities are derived from NH surface groups generated during the NH3-plasma, which interact with the precursor molecules during the precursor pulse. We propose that the reaction of these surface groups with the precursor leads to additional deposition of Ag atoms during the precursor pulse compared to the H-2-plasma process, which explains the enhanced growth rate of the NH3-plasma process. |
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Wos |
000410868600012 |
Publication Date |
2017-08-09 |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
9 |
Open Access |
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Notes |
; M.M.M. and J.D. acknowledge the Fonds Wetenschappelijk Onderzoek Vlaanderen (FWO Vlaanderen) for financial support through a personal research grant. We also acknowledge FWO Vlaanderen for providing project funding for this work. We are grateful to the ESRF staff for smoothly running the synchrotron and beamline facilities. We also thank Olivier Janssens for performing the SEM measurements and Stefaan Broekaert for mechanical assistance. J.A.M. acknowledges the Flemish Government for long-term structural funding (Methusalem). ; |
Approved |
Most recent IF: 9.466 |
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Call Number |
UA @ admin @ c:irua:146757 |
Serial |
5983 |
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Permanent link to this record |
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Author |
Milat, O.; Van Tendeloo, G.; Amelinckx, S.; Wright, A.J.; Greaves, C. |
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Title |
Effect of the substitution Ba\leftrightarrow Sr on the Ga-1222 superstructure : an electron diffraction study |
Type |
A1 Journal article |
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Year |
1995 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
7 |
Issue |
9 |
Pages |
1709-1715 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The superstructure of the RE(2)(Sr0.85-xBaxNd0.15)(2)GaCU2O9 compound is found to change significantly with increasing substitution of Ba for Sr. Most of the changes take place in the (Sr0.85-xBaxNd0.15)O-GaO-(Sr0.85-xBaxNd0.15)O lamella, the rest of the basic structure being hardly affected. The structural changes for O less than or equal to x less than or equal to 0.65 are studied by electron diffraction. The arrangement of the chains of GaO4 tetrahedra in the Ba-free compound becomes disordered at x > 0.25. At x similar to 0.65 a rearrangement of the chains in the GaO layers takes place; they form a meandering arrangement, which can be described on a 4a(p) x 2a(p) x c(p) superlattice. This rearrangement is accompanied by ordering of Ba and Sr atoms in the adjacent (ST0.85-xBaxNd0.15)O layers. A simple scheme is proposed to explain the influence of the substitution of Ba for Sr on the linking of the GaO4 tetrahedra and on the geometry of the ''chains'' in the GaO layer. |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
A1995RW21200021 |
Publication Date |
2005-03-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
|
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record |
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|
Impact Factor |
8.354 |
Times cited |
|
Open Access |
|
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|
Notes |
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Approved |
no |
|
|
Call Number |
UA @ lucian @ c:irua:13326 |
Serial |
850 |
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Permanent link to this record |
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Author |
Mayda, S.; Monico, L.; Krishnan, D.; De Meyer, S.; Cotte, M.; Garrevoet, J.; Falkenberg, G.; Sandu, I.C.A.; Partoens, B.; Lamoen, D.; Romani, A.; Miliani, C.; Verbeeck, J.; Janssens, K. |
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Title |
A combined experimental and computational approach to understanding CdS pigment oxidation in a renowned early 20th century painting |
Type |
A1 Journal article |
|
Year |
2023 |
Publication |
Chemistry of materials |
Abbreviated Journal |
|
|
|
Volume |
35 |
Issue |
24 |
Pages |
10403-10415 |
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|
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Antwerp X-ray Imaging and Spectroscopy (AXIS) |
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|
Abstract |
Cadmium sulfide (CdS)-based yellow pigments have been used in a number of early 20th century artworks, including The Scream series painted by Edvard Munch. Some of these unique paintings are threatened by the discoloration of these CdS-based yellow oil paints because of the oxidation of the original sulfides to sulfates. The experimental data obtained here prove that moisture and cadmium chloride compounds play a key role in promoting such oxidation. To clarify how these two factors effectively prompt the process, we studied the band alignment between CdS, CdCl2, and Cd-(OH)Cl as well as the radicals center dot OH and H3O center dot by density functional theory (DFT) methods. Our results show that a stack of several layers of Cd-(OH)Cl creates a pocket of positive holes at the Cl-terminated surface and a pocket of electrons at the OH-terminated surface by leading in a difference in ionization energy at both surfaces. The resulting band alignment indicates that Cd-(OH)Cl can indeed play the role of an oxidative catalyst for CdS in a moist environment, thus providing an explanation for the experimental evidence. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
001133000900001 |
Publication Date |
2023-12-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0897-4756; 1520-5002 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
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|
Impact Factor |
8.6 |
Times cited |
|
Open Access |
|
|
|
Notes |
The experimental research on the cadmium yellow powders/paint mock-ups and The Scream (ca. 1910) was financially supported by the European Union, research projects IPERION-CH (H2020-INFRAIA-2014-2015, GA no. 654028) and IPERION-HS (H2020-INFRAIA-2019-1, GA no. 871034) and the project AMIS within the program Dipartimenti di Eccellenza 2018-2022 (funded by MUR and the University of Perugia). For the beamtime grants received, the authors thank the ESRF-ID21 beamline (experiments HG64 and HG95), the DESY-P06 beamline, a member of the Helmholtz Association HGF (experiments I-20130221 EC and I-20160126 EC), and the project CALIPSOplus under the GA no. 730872 from the E.U. Framework Programme for Research and Innovation Horizon 2020. All of the staff of the MUNCH Museum (Conservation Department) is acknowledged for their collaboration. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the FWO – Vlaanderen and the Flemish Government, Department EWI. |
Approved |
Most recent IF: 8.6; 2023 IF: 9.466 |
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|
Call Number |
UA @ admin @ c:irua:202836 |
Serial |
8999 |
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Permanent link to this record |
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Author |
Marchetti, A.; Saniz, R.; Krishnan, D.; Rabbachin, L.; Nuyts, G.; De Meyer, S.; Verbeeck, J.; Janssens, K.; Pelosi, C.; Lamoen, D.; Partoens, B.; De Wael, K. |
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Title |
Unraveling the Role of Lattice Substitutions on the Stabilization of the Intrinsically Unstable Pb2Sb2O7Pyrochlore: Explaining the Lightfastness of Lead Pyroantimonate Artists’ Pigments |
Type |
A1 Journal article |
|
Year |
2020 |
Publication |
Chemistry Of Materials |
Abbreviated Journal |
Chem Mater |
|
|
Volume |
32 |
Issue |
7 |
Pages |
2863-2873 |
|
|
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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|
Abstract |
The pyroantimonate pigments Naples yellow and lead tin antimonate yellow are recognized as some of the most stable synthetic yellow pigments in the history of art. However, this exceptional lightfastness is in contrast with experimental evidence suggesting that this class of mixed oxides is of semiconducting nature. In this study the electronic structure and light-induced behavior of the lead pyroantimonate pigments were determined by means of a combined multifaceted analytical and computational approach (photoelectrochemical measurements, UV-vis diffuse reflectance spectroscopy, STEM-EDS, STEM-HAADF, and density functional theory calculations). The results demonstrate both the semiconducting nature and the lightfastness of these pigments. Poor optical absorption and minority carrier mobility are the main properties responsible for the observed stability. In addition, novel fundamental insights into the role played by Na atoms in the stabilization of the otherwise intrinsically unstable Pb2Sb2O7 pyrochlore were obtained. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000526394000016 |
Publication Date |
2020-04-14 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0897-4756 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
8.6 |
Times cited |
8 |
Open Access |
OpenAccess |
|
|
Notes |
Universiteit Antwerpen; Belgian Federal Science Policy Office; |
Approved |
Most recent IF: 8.6; 2020 IF: 9.466 |
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Call Number |
EMAT @ emat @c:irua:168819 |
Serial |
6363 |
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Permanent link to this record |
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Author |
Manzaneda-Gonzalez, V.; Jenkinson, K.; Pena-Rodriguez, O.; Borrell-Grueiro, O.; Trivino-Sanchez, S.; Banares, L.; Junquera, E.; Espinosa, A.; Gonzalez-Rubio, G.; Bals, S.; Guerrero-Martinez, A. |
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Title |
From multi- to single-hollow trimetallic nanocrystals by ultrafast heating |
Type |
A1 Journal article |
|
Year |
2023 |
Publication |
Chemistry of materials |
Abbreviated Journal |
|
|
|
Volume |
35 |
Issue |
22 |
Pages |
9603-9612 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Metal nanocrystals (NCs) display unique physicochemical features that are highly dependent on nanoparticle dimensions, anisotropy, structure, and composition. The development of synthesis methodologies that allow us to tune such parameters finely emerges as crucial for the application of metal NCs in catalysis, optical materials, or biomedicine. Here, we describe a synthetic methodology to fabricate hollow multimetallic heterostructures using a combination of seed-mediated growth routes and femtosecond-pulsed laser irradiation. The envisaged methodology relies on the coreduction of Ag and Pd ions on gold nanorods (Au NRs) to form Au@PdAg core-shell nanostructures containing small cavities at the Au-PdAg interface. The excitation of Au@PdAg NRs with low fluence femtosecond pulses was employed to induce the coalescence and growth of large cavities, forming multihollow anisotropic Au@PdAg nanostructures. Moreover, single-hollow alloy AuPdAg could be achieved in high yield by increasing the irradiation energy. Advanced electron microscopy techniques, energy-dispersive X-ray spectroscopy (EDX) tomography, X-ray absorption near-edge structure (XANES) spectroscopy, and finite differences in the time domain (FDTD) simulations allowed us to characterize the morphology, structure, and elemental distribution of the irradiated NCs in detail. The ability of the reported synthesis route to fabricate multimetallic NCs with unprecedented hollow nanostructures offers attractive prospects for the fabrication of tailored high-entropy alloy nanoparticles. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
001110623500001 |
Publication Date |
2023-11-06 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0897-4756; 1520-5002 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
8.6 |
Times cited |
2 |
Open Access |
OpenAccess |
|
|
Notes |
|
Approved |
Most recent IF: 8.6; 2023 IF: 9.466 |
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Call Number |
UA @ admin @ c:irua:202144 |
Serial |
9040 |
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Permanent link to this record |
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Author |
Mandal, T.K.; Abakumov, A.M.; Hadermann, J.; Van Tendeloo, G.; Croft, M.; Greenblatt, M. |
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Title |
Synthesis, crystal structure, and magnetic properties of Srl.31Co0.63Mn0.3703: a reivative of the incommensurate composite hexagonal perovskite structure |
Type |
A1 Journal article |
|
Year |
2007 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
|
|
Volume |
19 |
Issue |
25 |
Pages |
6158-6167 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
|
Wos |
000251422000019 |
Publication Date |
2007-11-13 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
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|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
9.466 |
Times cited |
5 |
Open Access |
|
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|
Notes |
|
Approved |
Most recent IF: 9.466; 2007 IF: 4.883 |
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Call Number |
UA @ lucian @ c:irua:67597 |
Serial |
3449 |
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Permanent link to this record |
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Author |
Malo, S.; Lepoittevin, C.; Pérez, O.; Hébert, S.; Van Tendeloo, G.; Hervieu, M. |
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Title |
Incommensurate crystallographic shear structures and magnetic properties of the cation deficient perovskite (Sr0.61Pb0.18)(Fe0.75Mn0.25)O2.29 |
Type |
A1 Journal article |
|
Year |
2010 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
22 |
Issue |
5 |
Pages |
1788-1797 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The origin of the incommensurability in the crystallographic shear (CS) structure of the ferri-Manganite (Sr0.61Pb0.18)(Fe0.75Mn0.25)O2.29, related to the cation deficient perovskite, has been determined by careful analysis of the boundaries between the two variants constituting the phasoid. High Resolution Electron Microscopy/HAADF-STEM images allow the structural mechanisms to be understood through the presence of structural units common to both phases, responsible of the incommensurate character observed in the electron diffraction patterns. The structural analysis allows for identifying different types of CS phases in the Pb−Sr−Fe(Mn)−O diagram and shows that the stabilization of the six-sided tunnels requires a higher A/B cationic ratio. A description of these phases is proposed through simple structural building units (SBU), based on chains of octahedra bordered by two pyramids. The (Sr0.61Pb0.18)(Fe0.75Mn0.25)O2.29 CS compound exhibits a strong antiferromagnetic and insulating behavior, similar to the Fe-2201 and terrace ferrites but differs by the presence of a hysteresis, with a small coercive field. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000274929000025 |
Publication Date |
2010-01-19 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
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ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
9.466 |
Times cited |
6 |
Open Access |
|
|
|
Notes |
Esteem 026019 |
Approved |
Most recent IF: 9.466; 2010 IF: 6.400 |
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|
Call Number |
UA @ lucian @ c:irua:81800 |
Serial |
1593 |
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Permanent link to this record |
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Author |
Luhrs, C.C.; Molins, E.; Van Tendeloo, G.; Beltran-Porter, D.; Fuertes, A. |
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Title |
Crystal structure of Bi6Sr8-xCa3+xO22(-0.5\leq x\leq1.7): a mixed valence bismuth oxide related to perovskite |
Type |
A1 Journal article |
|
Year |
1998 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
|
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Volume |
10 |
Issue |
7 |
Pages |
1875-1881 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The crystal structure of BiSr8-xCa3+xO22 has been determined by single-crystal X-ray diffraction. This phase is the same as Bi9Sr11Ca5Oy that was previously studied by several authors as a secondary phase in the Bi-Sr-Ca-Cu-O system and coexists in thermodynamic equilibrium with the superconductors Bi2Sr2CuO6 and Bi2Sr2CaCu2O8 It crystallizes in the monoclinic space group P2(1)/c, with cell parameters a 11.037(3) Angstrom, b = 5.971(2) Angstrom, c = 19.703(7) Angstrom, beta = 101.46(3)degrees Z = 2. The structure was solved by direct methods and full-matrix least-squares refinement. It is built up by perovskite-related blocks of composition [Sr8-xBi2Ca3+xO16] that intergrow with double rows [Bi4O6] running along b. The perovskite blocks are formed by groups of five octahedra that are shifted from each other 3/2 root 2a(p) along [110](p) (a(p) being the parameter of the cubic perovskite subcell) in a zigzag configuration and are aligned with this direction parallel to the one forming an angle of 25" with the c axis. In turn, the perovskite blocks [Sr8-xBi2Ca3+xO16] are shifted from each other 1/2 of both a(p) and root 2a(p) along [100](p) and [110](p), respectively. In the double rows, two trivalent bismuth atoms are placed, forming dimeric anion complexes [Bi2O6].(6-).6- The oxygen atoms around bismuth in these dimers are placed in the vertexes of a distorted trigonal bipyramid, with one vacant position that would be occupied by the lone pairs characteristic for the electronic configuration of Bi(III). The B sites in the perovskite blocks are occupied by pentavalent bismuth atoms and calcium atoms; the remaining Sr and Ca ions occupy the A sites of the perovskite blocks with coordination numbers with oxygen ranging from 10 to 12. The mean valence for Bi is +3.67 [33.3% of Bi(V) and 66.7% of Bi(III)]. The oxygen vacancies are located in the boundaries between domains having the two possible configurations of the perovskite subcell as in the anionic superconductor Bi3BaO5.5. The oxidation of Bi6Sr8-xCa3+xO22 at 650 degrees C allows the complete filling of the oxygen vacancies to form the double perovskite (Sr2-xCax)Bi1.4Ca0.6O6 that shows 92.5% of bismuth in +5 oxidation state. The experimental high-resolution electon microscopy image and the electron diffraction pattern of powder samples along the [010]* zone axis are in good agreement with those calculated from the structural model obtained by single-crystal X-ray diffraction. The material is almost free of defects and the occurrence of planar defects is very exceptional. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000075019300023 |
Publication Date |
2002-07-26 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
|
Edition |
|
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ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
9.466 |
Times cited |
6 |
Open Access |
|
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|
Notes |
|
Approved |
Most recent IF: 9.466; 1998 IF: 3.359 |
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Call Number |
UA @ lucian @ c:irua:104328 |
Serial |
570 |
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Permanent link to this record |
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Author |
Lottini, E.; López-Ortega, A.; Bertoni, G.; Turner, S.; Meledina, M.; Van Tendeloo, G.; de Julián Fernández, C.; Sangregorio, C. |
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Title |
Strongly Exchange Coupled Core|Shell Nanoparticles with High Magnetic Anisotropy: A Strategy toward Rare-Earth-Free Permanent Magnets |
Type |
A1 Journal article |
|
Year |
2016 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
|
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Volume |
28 |
Issue |
28 |
Pages |
4214-4222 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Antiferromagnetic(AFM)|ferrimagnetic(FiM) core|shell (CS) nanoparticles (NPs) of formula Co0.3Fe0.7O|Co0.6Fe2.4O4 with mean diameter from 6 to 18 nm have been synthesized through a one-pot thermal decomposition process. The CS structure has been generated by topotaxial oxidation of the core region, leading to the formation of a highly monodisperse single inverted AFM|FiM CS system with variable AFM-core diameter and constant FiM-shell thickness (~2 nm). The sharp interface, the high structural matching between both phases and the good crystallinity of the AFM material have been structurally demonstrated and are corroborated by the robust exchange-coupling between AFM and FiM phases, which gives rise to one among the largest exchange bias (HE) values ever reported for CS NPs (8.6 kOe) and to a strongly enhanced coercive field (HC). In addition, the investigation of the magnetic properties as a function of the AFM-core size (dAFM), revealed a non-monotonous trend of both HC and HE, which display a maximum value for dAFM = 5 nm (19.3 and 8.6 kOe, respectively). These properties induce a huge improvement of the capability of storing energy of the material, a result which suggests that the combination of highly anisotropic AFM|FiM materials can be an efficient strategy towards the realization of novel Rare Earth-free permanent magnets. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000378973100013 |
Publication Date |
2016-05-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
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ISSN |
0897-4756 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
9.466 |
Times cited |
48 |
Open Access |
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|
Notes |
This work was supported by the EU-FP7 through NANOPYME Project (No. 310516) and Integrated Infrastructure Initiative ESTEEM2 (No. 312483). S.T. gratefully acknowledges the FWO Flanders for a post-doctoral scholarship.; esteem2_ta |
Approved |
Most recent IF: 9.466 |
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|
Call Number |
c:irua:134084 c:irua:134084 |
Serial |
4092 |
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Permanent link to this record |
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Author |
Lisiecki, I.; Turner, S.; Bals, S.; Pileni, M.P.; Van Tendeloo, G. |
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Title |
The remarkable and intriguing resistance to oxidation of 2D ordered hcp Co nanocrystals: a new intrinsic property |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
21 |
Issue |
12 |
Pages |
2335-2338 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000267049200001 |
Publication Date |
2009-05-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
9.466 |
Times cited |
28 |
Open Access |
|
|
|
Notes |
Iap-Vi; Esteem 026019 |
Approved |
Most recent IF: 9.466; 2009 IF: 5.368 |
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Call Number |
UA @ lucian @ c:irua:77887 |
Serial |
2867 |
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Permanent link to this record |
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Author |
Linssen, T.; Cassiers, K.; Cool, P.; Lebedev, O.; Whittaker, A.; Vansant, E.F. |
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Title |
Physicochemical and structural characterization of mesoporous aluminosilicates synthesized from leached saponite with additional aluminum incorporation |
Type |
A1 Journal article |
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Year |
2003 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
15 |
Issue |
25 |
Pages |
4863-4873 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA) |
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Abstract |
A thorough investigation was performed on the physical (mechanical, thermal, and hydrothermal stability) and chemical (ion exchange capacity and silanol number) characteristics of aluminosilicate FSMs, synthesized via a new successful short-time synthesis route using leached saponite and a low concentration of CTAB. Moreover, the influence of an additional Al incorporation, utilizing different aluminum sources, on the structure of the FSM derived from saponite is studied. A mesoporous aluminosilicate with a low Si/Al ratio of 12.8 is synthesized, and still has a very large surface area of 1130 m(2)/g and pore volume of 0.92 cm(3)/g. The aluminum-containing samples all have a high cation exchange capacity of around 1 mmol/9 while they still have a silanol number of about 0.9 OH/nm(2); both characteristics being interesting for high-yield postsynthesis modification reactions. Finally, a study is performed on the transformation of the aluminosilicates into their Bronsted acid form via the exchange with ammonium ions and a consecutive heat treatment. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000187250800026 |
Publication Date |
2003-12-09 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
|
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ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
9.466 |
Times cited |
11 |
Open Access |
|
|
|
Notes |
|
Approved |
Most recent IF: 9.466; 2003 IF: 4.374 |
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Call Number |
UA @ lucian @ c:irua:103265 |
Serial |
2618 |
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Permanent link to this record |
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Author |
Li, Y.; Yang, X.-Y.; Tian, G.; Vantomme, A.; Yu, J.; Van Tendeloo, G.; Su, B.-L. |
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Title |
Chemistry of trimethyl aluminum: a spontaneous route to thermally stable 3D crystalline macroporous alumina foams with a hierarchy of pore sizes |
Type |
A1 Journal article |
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Year |
2010 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
22 |
Issue |
10 |
Pages |
3251-3258 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
A simple and spontaneous one-pot self-formation procedure that is easy to scale up has been developed based on the chemistry of trimethylaluminum (TMA), leading to thermally stable macroporous crystalline alumina with a very unique and unprecedented three-dimensional (3D) hierarchical pore structure consisting of well-defined wormlike mesopores. TMA is the precursor of both product and porogene (viz, two working functions within the same molecule (2 in 1)). The materials obtained have been intensively characterized by powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), N2 adsorption−desorption, and mercury porosimetry. The open cagelike macrocavities are self-constructed by mesoporous nanorods (diameter of ca. 40−70 nm), which are themselves formed by a random assembly of fibrous nanoparticles 5−6 nm in size. Optical microscopy (OM) has been used in situ to follow the synthesis procedure, which led to the proposal of the formation mechanism. Methane molecules as porogens, which were instantaneously released because of the fast hydrolysis of the chemical precursor, were the key factor in producing these 3D structures with uniform co-continuous macropores that interconnected directly with the wormlike mesopores. The important characteristic of this procedure is the concurrent formation of a multiscaled porous network. The material exhibits great thermal stability. The hierarchically mesoporous−macroporous Al2O3 obtained is quite attractive for a myriad of applications, from catalysis to biomedicine. The present work illustrates that the one-pot self-formation concept, based on the chemistry of alkyl metals, is a versatile method to design industrially valuable hierarchically porous materials. |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000277635000030 |
Publication Date |
2010-04-27 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
38 |
Open Access |
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Notes |
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Approved |
Most recent IF: 9.466; 2010 IF: 6.400 |
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Call Number |
UA @ lucian @ c:irua:82760 |
Serial |
356 |
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Permanent link to this record |
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Author |
Li, W.; Tong, W.; Yadav, A.; Bladt, E.; Bals, S.; Funston, A.M.; Etheridge, J. |
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Title |
Shape control beyond the seeds in gold nanoparticles |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
Chemistry Of Materials |
Abbreviated Journal |
Chem Mater |
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Volume |
33 |
Issue |
23 |
Pages |
9152-9164 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
In typical seed-mediated syntheses of metal nanocrystals, the shape of the nanocrystal is determined largely by the seed nucleation environment and subsequent growth environment (where “environment” refers to the chemical environment, including the surfactant and additives). In this approach, crystallinity is typically determined by the seeds, and surfaces are controlled by the environment(s). However, surface energies, and crystallinity, are both influenced by the choice of environment(s). This limits the permutations of crystallinity and surface facets that can be mixed and matched to generate new nanocrystal morphologies. Here, we control post-seed growth to deliberately incorporate twin planes during the growth stage to deliver new final morphologies, including twinned cubes and bipyramids from single-crystal seeds. The nature and number of twin planes, together with surfactant control of facet growth, define the final nanoparticle morphology. Moreover, by breaking symmetry, the twin planes introduce new facet orientations. This additional mechanism opens new routes for the synthesis of different morphologies and facet orientations. |
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Place of Publication |
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Wos |
000753956100012 |
Publication Date |
0000-00-00 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756; 1520-5002 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
3 |
Open Access |
Not_Open_Access |
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Notes |
This work was supported by the Australian Research Council (ARC) Grants DP160104679 and CE170100026 and used microscopes at the Monash Centre for Electron Microscopy funded by ARC Grants LE0454166, LE110100223, and LE140100104. W.L. thanks the support of the Australian Government Research Training Program (RTP) scholarship. W.T. thanks the Australian Department of Education and Monash University for the IPRS and APA scholarships. E.B. acknowledges financial support and a post-doctoral grant from the Research Foundation Flanders (FWO, Belgium). The authors thank Dr. Matthew Weyland and Dr. Tim Peterson for helpful discussions. A.Y. thanks the support from Post Graduation Publication Award (PPA) scholarship from Monash University. |
Approved |
Most recent IF: 9.466 |
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Call Number |
UA @ admin @ c:irua:187229 |
Serial |
7065 |
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Permanent link to this record |
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Author |
Lepoittevin, C.; Malo, S.; Nguyen, N.; Hebert, S.; Van Tendeloo, G.; Hervieu, M. |
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Title |
A layered iron-rich 2234-type with a mixed valence of iron: the ferrimagnetic Tl-doped Fe2(Sr2-\varepsilonTl\varepsilon)Sr3Fe4O14.65 |
Type |
A1 Journal article |
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Year |
2008 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
20 |
Issue |
20 |
Pages |
6468-6476 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
A new Tl-doped strontium ferrite Fe2(Sr2-Tl)Sr3Fe4O14.65, with an original structure, has been synthesized and structurally characterized by powder X-ray diffraction and transmission electron microscopy. The TGA and Mssbauer studies evidence a mixed valence of iron. The structure exhibits a commensurate modulation, with a F-type subcell a ≈ b ≈ 5.4 Å (≈ ap√2), c ≈ 42 Å with a modulation vector q = αa* with α = 0.4. The supercell parameters have been refined as a= 27.1101(8) Å, b= 5.5187(2) Å and c= 42.0513(9) Å, in the space group Fmmm. The electron diffraction and electron microscopy data of this novel ferrite show that it can be described as a FeTl-2234-type structure corresponding to the intergrowth of a quadruple perovskite slice [(SrFeO2.8)4], with a complex rock salt related slice [Fe2(Sr2-Tl)O3.4]∞, built up of one double iron layer [Fe2O2.4] sandwiched between two [SrO] layers. The HRTEM images show that the oxygen atoms and vacancies are randomly distributed in the perovskite layers while the HAADF STEM images evidence the absence of Tl segregation in the matrix. Fe2(Sr2-Tl)Sr3Fe4O14.65 exhibits a very large value of χ (11emu/mol) at 5 K, which remains large at 400 K; the M(H) loop presents a shape characteristic of ferrimagnetism, with a large coercive field of 0.3 T. The value of magnetization saturates at 400 K at 0.68 μB/Fe. At 10 K, the value of magnetization reaches a maximum of 2 μB/Fe. The resistivity presents a semiconducting-like behavior, with ρ 800 Ω·cm at 300 K. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000260254400030 |
Publication Date |
2008-09-25 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
8 |
Open Access |
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Notes |
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Approved |
Most recent IF: 9.466; 2008 IF: 5.046 |
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Call Number |
UA @ lucian @ c:irua:76671 |
Serial |
1804 |
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Permanent link to this record |