| Records |
| Author |
Hamelet, S.; Casas-Cabanas, M.; Dupont, L.; Davoisne, C.; Tarascon, J.M.; Masquelier, C. |
| Title |
Existence of superstructures due to large amounts of Fe vacancies in the LiFePO4-type framework |
Type |
A1 Journal article |
| Year |
2011 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
| Volume |
23 |
Issue |
1 |
Pages  |
32-38 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
LiFePO4 has been under intense scrutiny over the past decade because it stands as an attractive positive electrode material for the next generation of Li-ion batteries to power electric vehicles and hybrid electric vehicles, hence the importance of its thermal behavior. The reactivity of LiFePO4 with air at moderate temperatures is shown to be dependent on its particle size. For nanosized materials, a progressive displacement of Fe from the core structure leading to a composite made of nanosize Fe2O3 and highly defective, oxidized LixFeyPO4 compositions, among which the “ideal” formula LiFe2/3PO4. Herein we report, from both temperature-controlled X-ray diffraction and electronic diffraction microscopy, that these off-stoichiometry olivine-type compounds show a defect ordering resulting in the formation of a superstructure. Such a finding shows striking similarities with the temperature-driven oxidation of fayalite Fe2SiO4 (another olivine) to structurally defective laihunite, reported in the literature three decades ago. |
| 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 |
000285726900007 |
Publication Date |
2010-12-14 |
| 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 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
9.466 |
Times cited |
30 |
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 9.466; 2011 IF: 7.286 |
| Call Number |
UA @ lucian @ c:irua:105605 |
Serial |
1130 |
| Permanent link to this record |
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| Author |
Shetty, S.; Sinha, S.K.; Ahmad, R.; Singh, A.K.; Van Tendeloo, G.; Ravishankar, N. |
| Title |
Existence of Ti2+States on the Surface of Heavily Reduced SrTiO3Nanocubes |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
| Volume |
|
Issue |
|
Pages |
acs.chemmater.7b04113 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Using advanced electron microscopy, we demonstrate the presence of Ti2+ on the 001 surfaces of heavily reduced strontium titanate nanocubes. While high-angle annular dark field images show a clear difference between the surfaces of the unreduced and reduced samples, electron energy loss spectroscopy detects the presence of Ti2+ on the surface of the reduced cubes. Conventional reduction only leads to the formation of Ti3+ and involves the use of high temperatures. In our case, reduction is achieved at relatively lower temperatures in the solid state using sodium borohydride as the reducing agent. Our findings provide insights into the optical properties of the samples and provide a convenient method to produce highly reduced surfaces that could demonstrate a range of exotic physical phenomena |
| 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 |
000418206600005 |
Publication Date |
2017-11-17 |
| 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 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
9.466 |
Times cited |
8 |
Open Access |
OpenAccess |
| Notes |
We thank Advanced Facility for Microscopy and Microanalysis (AFMM), IISc, Bangalore for providing the TEM facility. We also thank MNCF, CeNSE, IISc for providing the XPS and FT-IR facilities. We acknowledge the help from Prof. Anshu Pandey for providing the PL facility and Mr. Ashutosh Gupta for the help with measurements. SS and NR thank DST for providing the financial support. RA and AKS acknowledge Super Computing Education and Research Center (SERC) and Materials Research Center (MRC), at IISc for providing required computational facilities. RA acknowledges the financial support from INSPIRE fellowship, AORC.Science and Engineering Research Board; Federaal Wetenschapsbeleid; Department of Science and Technology, Ministry of Science and Technology; |
Approved |
Most recent IF: 9.466 |
| Call Number |
UA @ lucian @c:irua:147191 |
Serial |
4767 |
| Permanent link to this record |
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| Author |
Imran, M.; Ramade, J.; Di Stasio, F.; De Franco, M.; Buha, J.; Van Aert, S.; Goldoni, L.; Lauciello, S.; Prato, M.; Infante, I.; Bals, S.; Manna, L. |
| Title |
Alloy CsCdxPb1–xBr3Perovskite Nanocrystals: The Role of Surface Passivation in Preserving Composition and Blue Emission |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Chemistry Of Materials |
Abbreviated Journal |
Chem Mater |
| Volume |
32 |
Issue |
|
Pages |
acs.chemmater.0c03825 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Various strategies have been proposed to engineer the band gap of metal halide perovskite nanocrystals (NCs) while preserving their structure and composition and thus ensuring spectral stability of the emission color. An aspect that has only been marginally investigated is how the type of surface passivation influences the structural/color stability of AMX3 perovskite NCs composed of two different M2+ cations. Here, we report the synthesis of blue-emitting Cs-oleate capped CsCdxPb1–xBr3 NCs, which exhibit a cubic perovskite phase containing Cd-rich domains of Ruddlesden–Popper phases (RP phases). The RP domains spontaneously transform into pure orthorhombic perovskite ones upon NC aging, and the emission color of the NCs shifts from blue to green over days. On the other hand, postsynthesis ligand exchange with various Cs-carboxylate or ammonium bromide salts, right after NC synthesis, provides monocrystalline NCs with cubic phase, highlighting the metastability of RP domains. When NCs are treated with Cs-carboxylates (including Cs-oleate), most of the Cd2+ ions are expelled from NCs upon aging, and the NCs phase evolves from cubic to orthorhombic and their emission color changes from blue to green. Instead, when NCs are coated with ammonium bromides, the loss of Cd2+ ions is suppressed and the NCs tend to retain their blue emission (both in colloidal dispersions and in electroluminescent devices), as well as their cubic phase, over time. The improved compositional and structural stability in the latter cases is ascribed to the saturation of surface vacancies, which may act as channels for the expulsion of Cd2+ ions from NCs. |
| 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 |
000603288800034 |
Publication Date |
2020-12-04 |
| 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 |
|
| ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
8.6 |
Times cited |
44 |
Open Access |
OpenAccess |
| Notes |
European Commission; Fonds Wetenschappelijk Onderzoek, G.0267.18N ; H2020 European Research Council, 770887 815128 851794 ; We acknowledge funding from the FLAG-ERA JTC2019 project PeroGas. S.B., and S.V.A. acknowledges funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program (ERC Consolidator Grants #815128REALNANO and #770887PICOMETRICS) and from the Research Foundation Flanders (FWO, Belgium) through project funding G.0267.18N. F.D.S. acknowledges the funding from ERC starting grant NANOLED (851794). The computational work was carried out on the Dutch National e-infrastructure with the support of the SURF Cooperative; sygma |
Approved |
Most recent IF: 8.6; 2020 IF: 9.466 |
| Call Number |
EMAT @ emat @c:irua:174004 |
Serial |
6659 |
| Permanent link to this record |
