Records |
Author |
Varykhalov, A.; Marchenko, D.; Sanchez-Barriga, J.; Scholz, M.R.; Verberck, B.; Trauzettel, B.; Wehling, T.O.; Carbone, C.; Rader, O. |
Title |
Intact dirac cones at broken sublattice symmetry : photoemission study of graphene on Ni and Co |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Physical review X |
Abbreviated Journal |
Phys Rev X |
Volume |
2 |
Issue |
4 |
Pages |
041017-10 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The appearance of massless Dirac fermions in graphene requires two equivalent carbon sublattices of trigonal shape. While the generation of an effective mass and a band gap at the Dirac point remains an unresolved problem for freestanding extended graphene, it is well established by breaking translational symmetry by confinement and by breaking sublattice symmetry by interaction with a substrate. One of the strongest sublattice-symmetry-breaking interactions with predicted and measured band gaps ranging from 400 meV to more than 3 eV has been attributed to the interfaces of graphene with Ni and Co, which are also promising spin-filter interfaces. Here, we apply angle-resolved photoemission to epitaxial graphene on Ni (111) and Co(0001) to show the presence of intact Dirac cones 2.8 eV below the Fermi level. Our results challenge the common belief that the breaking of sublattice symmetry by a substrate and the opening of the band gap at the Dirac energy are in a straightforward relation. A simple effective model of a biased bilayer structure composed of graphene and a sublattice-symmetry-broken layer, corroborated by density-functional-theory calculations, demonstrates the general validity of our conclusions. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
College Park, Md |
Editor |
|
Language |
|
Wos |
000312703200001 |
Publication Date |
2012-12-22 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
2160-3308; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
12.789 |
Times cited |
86 |
Open Access |
|
Notes |
; A. V. acknowledges helpful discussions with N. Sandler. This work was supported by SPP 1459 of the Deutsche Forschungsgemeinschaft. B. V. acknowledges support from the Research Foundation Flanders (FWO-Vlaanderen). B. T. and T. O. W. would like to thank the KITP at Santa Barbara for hospitality during the completion of this work. ; |
Approved |
Most recent IF: 12.789; 2012 IF: 6.711 |
Call Number |
UA @ lucian @ c:irua:105964 |
Serial |
1677 |
Permanent link to this record |
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Author |
Barhoum, A.; Van Assche, G.; Rahier, H.; Fleisch, M.; Bals, S.; Delplancked, M.-P.; Leroux, F.; Bahnemann, D. |
Title |
Sol-gel hot injection synthesis of ZnO nanoparticles into a porous silica matrix and reaction mechanism |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Materials & design |
Abbreviated Journal |
Mater Design |
Volume |
119 |
Issue |
119 |
Pages |
270-276 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Despite the enormous interest in the properties and applications of porous silica matrix, only a few attempts have been reported to deposit metal and metal oxide nanoparticles (NPs) inside the porous silica matrix. We report a simple approach (i.e. sol-gel hot injection) for insitu synthesis of ZnO NPs inside a porous silica matrix. Control of the Zn:Si molar ratio, reaction temperature, pH value, and annealing temperature permits formation of ZnO NPs (<= 10 nm) inside a porous silica particles, without additives or organic solvents. Results revealed that a solid state reaction inside the ZnO/SiO2 nanocomposites occurs with increasing the annealing temperature. The reaction of ZnO NPs with SiO2 matrix was insignificant up to approximately 500 degrees C. However, ZnO NPs react strongly with the silica matrix when the nanocomposites are annealed at temperatures above 700 degrees C. Extensive annealing of the ZnO/SiO2 nanocomposite at 900 degrees C yields 3D structures made of 500 nm rod-like, 5-7 pm tube-like and 35 pm needle-like Zn2SiO4 crystals. A possible mechanism for forming ZnO NPs inside porous silica matrix and phase transformation of the ZnO/SiO2 nanocomposites into 3D architectures of Zn2SiO4 are carefully discussed. (C) 2017 Elsevier Ltd. All rights reserved. |
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 |
000397360000030 |
Publication Date |
2017-01-23 |
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 |
0264-1275 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.364 |
Times cited |
43 |
Open Access |
Not_Open_Access |
Notes |
; A.B. would like to thank FWO – Research Foundation Flanders (grant no. V450315N) and the Strategic Initiative Materials in Flanders (SBO-project no. 130529 – INSITU) for financial support. TEM and TEM-EDX analyses were performed by Dr. F. Leroux (EMAT, Universiteit Antwerpen). XRD and DSC measurements were performed by T. Segato (4MAT, Universite Libre de Bruxelles). Notes: the authors declare no competing for financial interest. ; |
Approved |
Most recent IF: 4.364 |
Call Number |
UA @ lucian @ c:irua:142394UA @ admin @ c:irua:142394 |
Serial |
4689 |
Permanent link to this record |
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|
|
Author |
Wendelen, W.; Dzhurakhalov, A.A.; Peeters, F.M.; Bogaerts, A. |
Title |
Combined molecular dynamics: continuum study of phase transitions in bulk metals under ultrashort pulsed laser irradiation |
Type |
A1 Journal article |
Year |
2010 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
Volume |
114 |
Issue |
12 |
Pages |
5652-5660 |
Keywords |
A1 Journal article; Integrated Molecular Plant Physiology Research (IMPRES); Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
Abstract |
The phase transition processes induced by ultrashort, 100 fs pulsed laser irradiation of Au, Cu, and Ni are studied by means of a combined atomistic-continuum approach. A moderately low absorbed laser fluence range, from 200 to 600 J/m2 is considered to study phase transitions by means of a local and a nonlocal order parameter. At low laser fluences, the occurrence of layer-by-layer evaporation has been observed, which suggests a direct solid to vapor transition. The calculated amount of molten material remains very limited under the conditions studied, especially for Ni. Therefore, our results show that a kinetic equation that describes a direct solid to vapor transition might be the best approach to model laser-induced phase transitions by continuum models. Furthermore, the results provide more insight into the applicability of analytical superheating theories that were implemented in continuum models and help the understanding of nonequilibrium phase transitions. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000275855600044 |
Publication Date |
2010-01-26 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1932-7447;1932-7455; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.536 |
Times cited |
2 |
Open Access |
|
Notes |
; A.D. gratefully acknowledges Professor M. Hot (ULB, Brussels) for the basic MD-code that was modified further for the laser-induced melting processes. W.W, and A.D. are thankful to Professor L.V. Zhigilei for useful discussions and advices. The calculations were performed on the CALCUA computing facility of the University of Antwerp. This work was supported by the Belgian Science Policy (IAP). ; |
Approved |
Most recent IF: 4.536; 2010 IF: 4.524 |
Call Number |
UA @ lucian @ c:irua:81391 |
Serial |
402 |
Permanent link to this record |
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|
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Author |
Dzhurakhalov, A.A.; Peeters, F.M. |
Title |
Structure and energetics of hydrogen chemisorbed on a single graphene layer to produce graphane |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Carbon |
Abbreviated Journal |
Carbon |
Volume |
49 |
Issue |
10 |
Pages |
3258-3266 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Integrated Molecular Plant Physiology Research (IMPRES) |
Abstract |
Chemisorption of hydrogen on graphene is studied using atomistic simulations with the second generation of reactive empirical bond order Brenner inter-atomic potential. The lowest energy adsorption sites and the most important metastable sites are determined. The H concentration is varied from a single H atom, to clusters of H atoms up to full coverage. We found that when two or more H atoms are present, the most stable configurations of H chemisorption on a single graphene layer are ortho hydrogen pairs adsorbed on one side or on both sides of the graphene sheet. The latter has the highest hydrogen binding energy. The next stable configuration is the orthopara pair combination, and then para hydrogen pairs. The structural changes of graphene caused by chemisorbed hydrogen are discussed and are compared with existing experimental data and other theoretical calculations. The obtained results will be useful for nanoengineering of graphene by hydrogenation and for hydrogen storage. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Oxford |
Editor |
|
Language |
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Wos |
000291959300014 |
Publication Date |
2011-04-15 |
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 |
0008-6223; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.337 |
Times cited |
46 |
Open Access |
|
Notes |
; A.D. thanks M.W. Zhao for a useful correspondence. This work was supported by the Belgian Science Policy (IAP) and the Flemish Science Foundation (FWO-VI). ; |
Approved |
Most recent IF: 6.337; 2011 IF: 5.378 |
Call Number |
UA @ lucian @ c:irua:90877 |
Serial |
3275 |
Permanent link to this record |
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Author |
Kertik, A.; Wee, L.H.; Pfannmöller, M.; Bals, S.; Martens, J.A.; Vankelecom, I.F.J. |
Title |
Highly selective gas separation membrane using in situ amorphised metal-organic frameworks |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Energy & environmental science |
Abbreviated Journal |
Energ Environ Sci |
Volume |
10 |
Issue |
10 |
Pages |
2342-2351 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
Conventional carbon dioxide (CO2) separation in the petrochemical industry via cryogenic distillation is energy intensive and environmentally unfriendly. Alternatively, polymer membrane-based separations are of significant interest owing to low production cost, low-energy consumption and ease of upscaling. However, the implementation of commercial polymeric membranes is limited by their permeability and selectivity trade-off and the insufficient thermal and chemical stability. Herein, a novel type of amorphous mixed matrix membrane (MMM) able to separate CO2/CH4 mixtures with the highest selectivities ever reported for MOF based MMMs is presented. The MMM consists of an amorphised metal-organic framework (MOF) dispersed in an oxidatively cross-linked matrix achieved by fine tuning of the thermal treatment temperature in air up to 350 degrees C which drastically boosts the separation properties of the MMM. Thanks to the protection of the surrounding polymer, full oxidation of this MOF (i.e. ZIF-8) is prevented, and amorphisation of the MOF is realized instead, thus in situ creating a molecular sieve network. In addition, the treatment also improves the filler-polymer adhesion and induces an oxidative cross-linking of the polyimide matrix, resulting in MMMs with increased stability or plasticization resistance at high pressure up to 40 bar, marking a new milestone as new molecular sieve MOF MMMs for challenging natural gas purification applications. A new field for the use of amorphised MOFs and a variety of separation opportunities for such MMMs are thus opened. |
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 |
000414774500007 |
Publication Date |
2017-08-09 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1754-5692; 1754-5706 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
29.518 |
Times cited |
122 |
Open Access |
OpenAccess |
Notes |
; A.K. acknowledges financial support from the Erasmus-Mundus Doctorate in Membrane Engineering (EUDIME) Programme. L.H.W. thanks the FWO-Vlaanderen for a postdoctoral research fellowship (12M1415N). M. P. acknowledges financial support by the FP7 European project SUNFLOWER (FP7 #287594). S. B. acknowledges financial support from European Research Council (ERC Starting Grant # 335078-COLOURATOMS). J. A. M. gratefully acknowledges financial supports from the Flemish Government for long-term Methusalem funding. J. A. M. and I. F. J. V. acknowledge the Belgian Government for IAP-PAI networking. A. K. would also like to thank Frank Mathijs for the mechanical tests, Roy Bernstein for the XPS analysis and Lien Telen and Bart Goderis for the DSC measurements. We thank Verder Scientific Benelux for providing the service of ZIF-8 ball milling. ; ecas_sara |
Approved |
Most recent IF: 29.518 |
Call Number |
UA @ lucian @ c:irua:147399UA @ admin @ c:irua:147399 |
Serial |
4879 |
Permanent link to this record |
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Author |
Benetti, G.; Caddeo, C.; Melis, C.; Ferrini, G.; Giannetti, C.; Winckelmans, N.; Bals, S.; J Van Bael, M.; Cavaliere, E.; Gavioli, L.; Banfi, F. |
Title |
Bottom-Up Mechanical Nanometrology of Granular Ag Nanoparticles Thin Films |
Type |
A1 Journal article |
Year |
2017 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
Volume |
121 |
Issue |
121 |
Pages |
22434-22441 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
Ultrathin metal nanoparticles coatings, synthesized by gas-phase deposition, are emerging as go-to materials in a variety of fields ranging from pathogens control, sensing to energy storage. Predicting their morphology and mechanical properties beyond a trial-and-error approach is a crucial issue limiting their exploitation in real-life applications. The morphology and mechanical properties of Ag nanoparticles ultrathin films, synthesized by supersonic cluster beam deposition, are here assessed adopting a bottom-up, multi-technique approach. A virtual film model is proposed merging high resolution scanning transmission electron microscopy, supersonic cluster beam dynamics and molecular dynamics simulations. The model is validated against mechanical nanometrology measurements and is readily extendable to metals other than Ag. The virtual film is shown to be a flexible and reliable predictive tool to access morphology-dependent properties such as mesoscale gas-dynamics and elasticity of ultrathin films synthesized by gas-phase deposition. |
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 |
000413131700072 |
Publication Date |
2017-09-11 |
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 |
|
ISSN |
1932-7447 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.536 |
Times cited |
30 |
Open Access |
OpenAccess |
Notes |
; All authors thank Prof. Dr. Luciano Colombo for enlightening discussions. C.C. and F.B. acknowledge financial support from the MIUR Futuro in ricerca 2013 Grant in the frame of the ULTRANANO Project (Project No. RBFR13NEA4). F.B., G.F., and C.G. acknowledge support from Universita Cattolica del Sacro Cuore through D.2.2 and D.3.1 grants. F.B. acknowledges financial support from Fondazione E.U.L.O. The authors acknowledge financial support from the European Union through the seventh Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative (Reference No. 312483 ESTEEM2). ; |
Approved |
Most recent IF: 4.536 |
Call Number |
EMAT @ emat @c:irua:145828UA @ admin @ c:irua:145828 |
Serial |
4706 |
Permanent link to this record |
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Author |
Berends, A.C.; van der Stam, W.; Hofmann, J.P.; Bladt, E.; Meeldijk, J.D.; Bals, S.; de Donega, C.M. |
Title |
Interplay between surface chemistry, precursor reactivity, and temperature determines outcome of ZnS shelling reactions on CuInS2 nanocrystals |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
30 |
Issue |
30 |
Pages |
2400-2413 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
ZnS shelling of I-III-VI(2 )nanocrystals (NCs) invariably leads to blue-shifts in both the absorption and photoluminescence spectra. These observations imply that the outcome of ZnS shelling reactions on I-III-VI2 colloidal NCs results from a complex interplay between several processes taking place in solution, at the surface of, and within the seed NC. However, a fundamental understanding of the factors determining the balance between these different processes is still lacking. In this work, we address this need by investigating the impact of precursor reactivity, reaction temperature, and surface chemistry (due to the washing procedure) on the outcome of ZnS shelling reactions on CuInS2 NCs using a seeded growth approach. We demonstrate that low reaction temperatures (150 degrees C) favor etching, cation exchange, and alloying regardless of the precursors used. Heteroepitaxial shell overgrowth becomes the dominant process only if reactive S- and Zn-precursors (S-ODE/OLAM and ZnI2 ) and high reaction temperatures (210 degrees C) are used, although a certain degree of heterointerfacial alloying still occurs. Remarkably, the presence of residual acetate at the surface of CIS seed NCs washed with ethanol is shown to facilitate heteroepitaxial shell overgrowth, yielding for the first time CIS/ZnS core/shell NCs displaying red-shifted absorption spectra, in agreement with the spectral shifts expected for a type-I band alignment. The insights provided by this work pave the way toward the design of improved synthesis strategies to CIS/ZnS core/shell and alloy NCs with tailored elemental distribution profiles, allowing precise tuning of the optoelectronic properties of the resulting materials. |
Address |
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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 |
Editor |
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Language |
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Wos |
000430023700027 |
Publication Date |
2018-03-25 |
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 |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
85 |
Open Access |
OpenAccess |
Notes |
; Annelies van der Bok is gratefully acknowledged for performing the ICP measurements. A.C.B. and C.d.M.D. acknowledge financial support from the division of Chemical Sciences (CW) of The Netherlands Organization for Scientific Research (NWO) under Grant No. ECHO.712.014.001. S.B. and E.B. acknowledge financial support from European Research Council (ERC Starting Grant No. 335078-COLOURATOMS). ; Ecas_Sara |
Approved |
Most recent IF: 9.466 |
Call Number |
UA @ lucian @ c:irua:150772UA @ admin @ c:irua:150772 |
Serial |
4972 |
Permanent link to this record |
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Author |
Vishwakarma, M.; Agrawal, K.; Hadermann, J.; Mehta, B.R. |
Title |
Investigating the effect of sulphurization on volatility of compositions in Cu-poor and Sn-rich CZTS thin films |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Applied Surface Science |
Abbreviated Journal |
Appl Surf Sci |
Volume |
507 |
Issue |
|
Pages |
145043 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
In the present work, the Cu-poor and Sn-rich CZTS thin films were prepared in order to study the volatility of Sn with respect to other components. Thin film compositions were kept intentionally Sn-rich to understand the behaviour of loss and segregation of Sn during sulphurization. The homogeneous composition distribution in precursor thin films turns heterogeneous with a change in morphology after sulphurization. The inability of identifying nanoscale secondary phases in CZTS thin film by conventional analytical techniques such as XRD and Raman, can be fulfilled by employing HAADF-STEM analysis. XPS and HAADF-STEM analyses provide the quantification of nanoscale secondary phases across the thin film and surface, respectively. The volatility of Sn was revealed in the form of segregation in the middle layer of CZTS cross-sectional lamella rather than loss to annealing atmosphere. It was observed that among the cations of CZTS, Sn segregates more than Cu, while Zn segregates least. The nanoscale spurious phases were observed to vary across different regions in the sulphurized CZTS sample. The reactive annealing lead to grain growth and formation of grain boundary features in the CZTS thin films, where annealing significantly modifies the potential difference and band bending at grain boundaries with respect to intra-grains. |
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 |
000520021200053 |
Publication Date |
2019-12-13 |
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 |
0169-4332 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.7 |
Times cited |
4 |
Open Access |
OpenAccess |
Notes |
; Authors acknowledges support provided by DST, India in the forms of InSOL project. We also acknowledge Dr. Indrani Mishra for XPS measurements and DST-FIST Raman facility for Raman measurements. Manoj Vishwakarma acknowledges IIT Delhi, New Delhi, India for MHRD fellowship. Prof. B.R. Mehta acknowledges the support of the Schlumberger chair professorship. ; |
Approved |
Most recent IF: 6.7; 2020 IF: 3.387 |
Call Number |
UA @ admin @ c:irua:168603 |
Serial |
6552 |
Permanent link to this record |
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Author |
Vishwakarma, M.; Varandani, D.; Hendrickx, M.; Hadermann, J.; Mehta, B.R. |
Title |
Nanoscale photovoltage mapping in CZTSe/CuxSe heterostructure by using kelvin probe force microscopy |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Materials Research Express |
Abbreviated Journal |
|
Volume |
7 |
Issue |
1 |
Pages |
016418 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
In the present work, kelvin probe force microscopy (KPFM) technique has been used to study the CZTSe/CuxSe bilayer interface prepared by multi-step deposition and selenization process of metal precursors. Transmission electron microscopy (TEM) confirmed the bilayer configuration of the CZTSe/CuxSe sample. Two configuration modes (surface mode and junction mode) in KPFM have been employed in order to measure the junction voltage under illumination conditions. The results show that CZTSe/CuxSe has small junction voltage of similar to 21 mV and the presence of CuxSe secondary phase in the CZTSe grain boundaries changes the workfunction of the local grain boundaries region. The negligible photovoltage difference between grain and grain boundaries in photovoltage image indicates that CuxSe phase deteriorates the higher photovoltage at grain boundaries normally observed in CZTSe based device. These results can be important for understanding the role of secondary phases in CZTSe based junction devices. |
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 |
000520120900001 |
Publication Date |
2019-12-27 |
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 |
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ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
OpenAccess |
Notes |
; Authors acknowledges support provided DST in the forms of InSOL and Indo-Swiss projects. We also acknowledge Joke Hadermann EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Belgium for helping in TEM measurements. M V Manoj Vishwakarma acknowledges IIT Delhi for MHRD fellowship. Prof B R Mehta acknowledges the support of the Schlumberger chair professorship. M V also acknowledges the support of DST-FIST Raman facility. ; |
Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:167843 |
Serial |
6567 |
Permanent link to this record |
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Author |
Elia, A.; De Wael, K.; Dowsett, M.; Adriaens, A. |
Title |
Electrochemical deposition of a copper carboxylate layer on copper as potential corrosion inhibitor |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of solid state electrochemistry |
Abbreviated Journal |
J Solid State Electr |
Volume |
16 |
Issue |
1 |
Pages |
143-148 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
Abstract |
Carboxylic acids and sodium carboxylates are used to protect metals against aqueous and atmospheric corrosion. In this paper, we describe the application of a layer of copper carboxylate on the surface of a copper electrode by means of cyclic voltammetry technique and tests which measure the corresponding resistance to aqueous corrosion. Unlike the soaking process, which also forms a film on the surface, the use of cyclic voltammetry allows one to follow the deposition process of the copper carboxylates onto the electrode. The modified electrodes have been characterised with infrared spectroscopy. In addition, the corrosion resistance of the film has been investigated using polarisation resistance and Tafel plot measurements. |
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 |
000298651700018 |
Publication Date |
2011-01-25 |
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 |
|
ISSN |
1432-8488 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.316 |
Times cited |
8 |
Open Access |
|
Notes |
; Authors would like to acknowledge the Research Foundation-Flanders (FWO) for funding assistance (A. Elia is a FWO aspirant) and V. Vermeersch and S. Van Vlierberghe (Ghent University, Polymer Chemistry and Biomaterials Research Group) for the FTIR-ATR measurements. ; |
Approved |
Most recent IF: 2.316; 2011 IF: 2.131 |
Call Number |
UA @ admin @ c:irua:89618 |
Serial |
5588 |
Permanent link to this record |
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Author |
Kao, K.-H.; Verhulst, A.S.; Van de Put, M.; Vandenberghe, W.G.; Sorée, B.; Magnus, W.; De Meyer, K. |
Title |
Tensile strained Ge tunnel field-effect transistors: k\cdot p material modeling and numerical device simulation |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
Volume |
115 |
Issue |
4 |
Pages |
044505-44508 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Group IV based tunnel field-effect transistors generally show lower on-current than III-V based devices because of the weaker phonon-assisted tunneling transitions in the group IV indirect bandgap materials. Direct tunneling in Ge, however, can be enhanced by strain engineering. In this work, we use a 30-band k.p method to calculate the band structure of biaxial tensile strained Ge and then extract the bandgaps and effective masses at Gamma and L symmetry points in k-space, from which the parameters for the direct and indirect band-to-band tunneling (BTBT) models are determined. While transitions from the heavy and light hole valence bands to the conduction band edge at the L point are always bridged by phonon scattering, we highlight a new finding that only the light-holelike valence band is strongly coupling to the conduction band at the Gamma point even in the presence of strain based on the 30-band k.p analysis. By utilizing a Technology Computer Aided Design simulator equipped with the calculated band-to-band tunneling BTBT models, the electrical characteristics of tensile strained Ge point and line tunneling devices are self-consistently computed considering multiple dynamic nonlocal tunnel paths. The influence of field-induced quantum confinement on the tunneling onset is included. Our simulation predicts that an on-current up to 160 (260) mu A/mu m can be achieved along with on/off ratio > 10(6) for V-DD = 0.5V by the n-type (p-type) line tunneling device made of 2.5% biaxial tensile strained Ge. (C) 2014 AIP Publishing LLC. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000331210800113 |
Publication Date |
2014-01-26 |
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 |
0021-8979;1089-7550; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.068 |
Times cited |
26 |
Open Access |
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Notes |
; Authors would like to thank Dr. Mohammad Ali Pourghaderi for useful discussions on the nonparabolicity. Authors would also like to thank Professor Eddy Simoen and Dr. Yosuke Shimura for useful discussions about the validity of modeled bandgaps and effective masses. This work was also supported by IMEC's Industrial Affiliation Program. ; |
Approved |
Most recent IF: 2.068; 2014 IF: 2.183 |
Call Number |
UA @ lucian @ c:irua:115800 |
Serial |
3505 |
Permanent link to this record |
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Author |
Bueken, B.; Van Velthoven, N.; Willhammar, T.; Stassin, T.; Stassen, I.; Keen, D.A.; Baron, G.V.; Denayer, J.F.M.; Ameloot, R.; Bals, S.; De Vos, D.; Bennett, T.D. |
Title |
Gel-based morphological design of zirconium metal-organic frameworks |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Chemical science |
Abbreviated Journal |
Chem Sci |
Volume |
8 |
Issue |
8 |
Pages |
3939-3948 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The ability of metal-organic frameworks (MOFs) to gelate under specific synthetic conditions opens up new opportunities in the preparation and shaping of hierarchically porous MOF monoliths, which could be directly implemented for catalytic and adsorptive applications. In this work, we present the first examples of xero-or aerogel monoliths consisting solely of nanoparticles of several prototypical Zr4+-based MOFs: UiO-66-X (X – H, NH2, NO2, (OH)(2)), UiO-67, MOF-801, MOF-808 and NU-1000. High reactant and water concentrations during synthesis were observed to induce the formation of gels, which were converted to monolithic materials by drying in air or supercritical CO2. Electron microscopy, combined with N-2 physisorption experiments, was used to show that irregular nanoparticle packing leads to pure MOF monoliths with hierarchical pore systems, featuring both intraparticle micropores and interparticle mesopores. Finally, UiO-66 gels were shaped into monolithic spheres of 600 mm diameter using an oil-drop method, creating promising candidates for packed-bed catalytic or adsorptive applications, where hierarchical pore systems can greatly mitigate mass transfer limitations. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
Royal Society of Chemistry |
Place of Publication |
Cambridge |
Editor |
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Language |
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Wos |
000400553000077 |
Publication Date |
2017-03-23 |
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 |
2041-6520 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.668 |
Times cited |
168 |
Open Access |
OpenAccess |
Notes |
; B. B., T. S. and I. S. acknowledge the FWO Flanders (doctoral and post-doctoral grants). T. W. acknowledges a post-doctoral grant from the Swedish Research Council. T. D. B. acknowledges the Royal Society (University Research Fellowship) and Trinity Hall (University of Cambridge) for funding. S. B. and D. D. V. are grateful for funding by Belspo (IAP 7/05 P6/27) and by the FWO Flanders. D. D. V. further acknowledges funding from the European Research Council (project H-CCAT). S. B. acknowledges financial support from the European Research Council (ERC Starting Grant #335078-COLOURATOMS). The authors acknowledge Arnau Carne and Shuhei Furukawa for assistance with supercritical CO<INF>2</INF> extraction, and Charles Ghesquiere for assistance in synthesis. ; Ecas_Sara |
Approved |
Most recent IF: 8.668 |
Call Number |
UA @ lucian @ c:irua:152643UA @ admin @ c:irua:152643 |
Serial |
5143 |
Permanent link to this record |
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Author |
Mortazavi, B.; Bafekry, A.; Shahrokhi, M.; Rabczuk, T.; Zhuang, X. |
Title |
ZnN and ZnP as novel graphene-like materials with high Li-ion storage capacities |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Materials today energy |
Abbreviated Journal |
|
Volume |
16 |
Issue |
|
Pages |
Unsp 100392-8 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
Abstract |
In this work, we employed first-principles density functional theory (DFT) calculations to investigate the dynamical and thermal stability of graphene-like ZnX (X = N, P, As) nanosheets. We moreover analyzed the electronic, mechanical and optical properties of these novel two-dimensional (2D) systems. Acquired phonon dispersion relations reveal the absence of imaginary frequencies and thus confirming the dynamical stability of predicted monolayers. According to ab-initio molecular dynamics results however only ZnN and ZnP exhibit the required thermally stability. The elastic modulus of ZnN, ZnP and ZnAs are estimated to be 31, 21 and 17 N/m, respectively, and the corresponding tensile strengths values are 6.0, 4.9 and 4.0 N/m, respectively. Electronic band structure analysis confirms the metallic electronic character for the predicted monolayers. Results for the optical characteristics also indicate a reflectivity of 100% at extremely low energy levels, which is desirable for photonic and optoelectronic applications. According to our results, graphene-like ZnN and ZnP nanosheets can yield high capacities of 675 and 556 mAh/g for Li-ion storage, respectively. Acquired results confirm the stability and acceptable strength of ZnN and ZnP nanosheets and highlight their attractive application prospects in optical and energy storage systems. |
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 |
000539083500049 |
Publication Date |
2020-02-21 |
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 |
|
ISSN |
2468-6069 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.3 |
Times cited |
13 |
Open Access |
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Notes |
; B. M. and X. Z. appreciate the funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453). ; |
Approved |
Most recent IF: 9.3; 2020 IF: NA |
Call Number |
UA @ admin @ c:irua:169752 |
Serial |
6655 |
Permanent link to this record |
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Author |
Ren, X.-N.; Hu, Z.-Y.; Jin, J.; Wu, L.; Wang, C.; Liu, J.; Liu, F.; Wu, M.; Li, Y.; Van Tendeloo, G.; Su, B.-L. |
Title |
Cocatalyzing Pt/PtO phase-junction nanodots on hierarchically porous TiO2 for highly enhanced photocatalytic hydrogen production |
Type |
A1 Journal article |
Year |
2017 |
Publication |
ACS applied materials and interfaces |
Abbreviated Journal |
Acs Appl Mater Inter |
Volume |
9 |
Issue |
35 |
Pages |
29687-29698 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
Phase-junctions. between a cocatalyst and its semiconductor host are quite effective to enhance the photo catalytic activity and are widely studied, while reports on the phase-juncted cocatalyst are still rare. In this work, we report the deposition of the Pt/PtO phase-juncted nanodots as cocatalyst via NaOH modification of an interconnected meso-macroporous TiO2 network with high surface area and inner-particle mesopores to enhance the performance of photocatalytic H-2 production. Our results show that NaOH modification can largely influence Pt/PtO phase-juncted nanodot formation and dispersity. Compared to the TiO2 nano particles, the hierarchically meso-macroporous TiO2 network containing 0.18 wt % Pt/PtO phase-juneted cocatalyst demonstrates a highest photocatalytic H-2 rate of 13 mmol g(-1) h(-1) under simulated solar light, and possesses a stable cycling activity without obvious decrease after five cycles. Such high H-2 production performance can be attributed to both the phase-juncted Pt/PtO providing more active sites while PtO suppresses the undesirable hydrogen back reaction, and the special hierarchically porous TiO2 network with inner-particle mesopores presenting short diffusion path lengths for photogenerated electrons and enhanced light harvesting efficiency. This work suggests that Pt/PtO phase-juncted cocatalyst on hierarchically porous TiO2 nanostructures is a promising strategy for advanced photocatalytic H-2 production. |
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 |
000410597500032 |
Publication Date |
2017-08-16 |
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 |
1944-8244 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
7.504 |
Times cited |
18 |
Open Access |
OpenAccess |
Notes |
; B.L.S. acknowledges the Chinese Central Government for an “Expert of the State” position in the Program of the “Thousand Talents”. Y.L. acknowledges the Hubei Provincial Department of Education for the “Chutian Scholar” program. This work is supported by the National Key Research and Development Program of China (2016YFA0202602), Program for Changjiang Scholars and Innovative Research Team in University (IRT_15R52), International Science & Technology Cooperation Program of China (2015DFE52870), National Natural Science Foundation of China (51502225), and the Fundamental Research Funds for the Central Universities (WUT: 2016III029). Z.Y.H. and G.V.T. acknowledge support from the EC Framework 7 program ESTEEM2 (Reference 312483). ; |
Approved |
Most recent IF: 7.504 |
Call Number |
UA @ lucian @ c:irua:146765 |
Serial |
4779 |
Permanent link to this record |
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Author |
Tunca, B.; Lapauw, T.; Callaert, C.; Hadermann, J.; Delville, R.; Caspi, E.'ad N.; Dahlqvist, M.; Rosen, J.; Marshal, A.; Pradeep, K.G.; Schneider, J.M.; Vleugels, J.; Lambrinou, K. |
Title |
Compatibility of Zr₂AlC MAX phase-based ceramics with oxygen-poor, static liquid lead-bismuth eutectic |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Corrosion Science |
Abbreviated Journal |
Corros Sci |
Volume |
171 |
Issue |
|
Pages |
108704-108719 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
This work investigates the compatibility of Zr2AlC MAX phase-based ceramics with liquid LBE, and proposes a mechanism to explain the observed local Zr2AlC/LBE interaction. The ceramics were exposed to oxygen-poor (C-O <= 2.2 x 10(-10) mass%), static liquid LBE at 500 degrees C for 1000 h. A new Zr-2(Al,Bi,Pb)C MAX phase solid solution formed in-situ in the LBE-affected Zr2AlC grains. Out-of-plane ordering was favorable in the new solid solution, whereby A-layers with high and low-Bi/Pb contents alternated in the crystal structure, in agreement with first-principles calculations. Bulk Zr-2(Al,Bi,Pb)C was synthesized by reactive hot pressing to study the crystal structure of the solid solution by neutron diffraction. |
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 |
000537624600005 |
Publication Date |
2020-04-27 |
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 |
0010-938x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.3 |
Times cited |
3 |
Open Access |
Not_Open_Access |
Notes |
; B.T. acknowledges the financial support of the SCK CEN Academy for Nuclear Science and Technology (Belgium). This research was partly funded by the European Atomic Energy Community's (Euratom) Seventh Framework Programme FP7/ 2007-2013 under Grant Agreement No. 604862 (FP7 MatISSE), the MYRRHA project (SCK CEN, Belgium), as well as by the Euratom research and training programme 2014-2018 under Grant Agreement No. 740415 (H2020 IL TROVATORE). The performed research falls within the framework of the EERA (European Energy Research Alliance) Joint Programme on Nuclear Materials (JPNM). The authors gratefully acknowledge the Hercules Foundation for Project AKUL/1319 (CombiS(T)EM)) and the Knut and Alice Wallenberg (KAW) foundation. The calculations were carried out using supercomputer resources provided by the Swedish National Infrastructure for Computing (SNIC) at the High Performance Computing Center North (HPC2N) and the PDC Center for High Performance Computing. E.N.C. thanks Offir Ozeri for his help in NPD data acquiring. ; |
Approved |
Most recent IF: 8.3; 2020 IF: 5.245 |
Call Number |
UA @ admin @ c:irua:170157 |
Serial |
6475 |
Permanent link to this record |
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Author |
Cagno, S.; van der Snickt, G.; Legrand, S.; Caen, J.; Patin, M.; Meulebroeck, W.; Dirkx, Y.; Hillen, M.; Steenackers, G.; Rousaki, A.; Vandenabeele, P.; Janssens, K. |
Title |
Comparison of four mobile, non‐invasive diagnostic techniques for differentiating glass types in historical leaded windows : MA‐XRF , UV–Vis–NIR, Raman spectroscopy and IRT |
Type |
A1 Journal article |
Year |
2020 |
Publication |
X-Ray Spectrometry |
Abbreviated Journal |
X-Ray Spectrom |
Volume |
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Issue |
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Pages |
xrs.3185-17 |
Keywords |
A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES) |
Abstract |
This paper critically compares the performance of four non-invasive techniques that match the accuracy, flexibility, time-efficiency, and transportability required for in situ characterization of leaded glass windows: macroscopic X-ray fluorescence imaging (MA-XRF), UV-Vis-NIR, Raman spectroscopy, and infrared thermography (IRT). In order to compare the techniques on equal grounds, all techniques were tested independently of each other by separate research groups on the same historical leaded window tentatively dated to the 17th century, without prior knowledge. The aim was to assess the ability of these techniques to document the conservation history of the window by classifying and grouping the colorless glass panes, based on differences in composition. IRT, MA-XRF and UV-Vis-NIR spectroscopy positively distinguished at least two glass groups, with MA-XRF providing the most detailed chemical information. In particular, based on the ratio between the network modifier (K) and network stabilizer (Ca) and on the level of colorants and decolorizers (Fe, Mn, As), the number of plausible glass families could be strongly reduced. In addition, UV-Vis-NIR detected cobalt at ppm level and gave more specific information on the chromophore Fe2+/Fe(3+)ratio. Raman spectroscopy was hampered by fluorescence caused by the metal ions of the decolorizer in most of the panes, but nevertheless identified one group as HLLA. |
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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 |
000561869600001 |
Publication Date |
2020-08-24 |
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 |
0049-8246 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.2 |
Times cited |
|
Open Access |
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Notes |
; Belgian Federal Science Policy Office, Grant/Award Number: BR/175/A3/FENESTRA; Fonds Wetenschappelijk Onderzoek, Grant/Award Number: 12X1919N; Baillet-Latour Fund ; |
Approved |
Most recent IF: 1.2; 2020 IF: 1.298 |
Call Number |
UA @ admin @ c:irua:170972 |
Serial |
6473 |
Permanent link to this record |
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Author |
Van Goethem, C.; Verbeke, R.; Pfanmoeller, M.; Koschine, T.; Dickmann, M.; Timpel-Lindner, T.; Egger, W.; Bals, S.; Vankelecom, I.F.J. |
Title |
The role of MOFs in Thin-Film Nanocomposite (TFN) membranes |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Journal of membrane science |
Abbreviated Journal |
J Membrane Sci |
Volume |
563 |
Issue |
563 |
Pages |
938-948 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Incorporation of MOFs in interfacially polymerized Thin-Film Nanocomposite (TFN) membranes has widely been shown to result in increased membrane performance. However, the exact functioning of these membranes is poorly understood as large variability in permeance increase, filler incorporation and rejection changes can be observed in literature. The synthesis and functioning of TFN membranes (herein exemplified by ZIF-8 filled polyamide (PA) membranes prepared via the EFP method) was investigated via targeted membrane synthesis and thorough characterization via STEM-EDX, XRD and PALS. It is hypothesized that the acid generated during the interfacial polymerization (IP) at least partially degrades the crystalline, acid-sensitive ZIF-8 and that this influences the membrane formation (through so-called secondary effects, i.e. not strictly linked to the pore morphology of the MOF). Nanoscale HAADF-STEM imaging and STEM-EDX Zn-mapping revealed no ZIF-8 particles but rather the presence of randomly shaped regions with elevated Zn-content. Also XRD failed to show the presence of crystalline areas in the composite PA films. As the addition of the acid-quenching TEA led to an increase in the diffraction signal observed in XRD, the role of the acid was confirmed. The separate addition of dissolved Zn2+ to the synthesis of regular TFC membranes showed an increase in permeance while losing some salt retention, similar to observations regularly made for TFN membranes. While the addition of a porous material to a TFC membrane is a straightforward concept, all obtained results indicate that the synthesis and performance of such composite membranes is often more complex than commonly accepted. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000441897200099 |
Publication Date |
2018-06-22 |
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 |
0376-7388 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.035 |
Times cited |
84 |
Open Access |
OpenAccess |
Notes |
; C.V.G. and R.V. kindly acknowledge respectively the Flemish Agency for Innovation through Science and Technology (IWT) (IWT, 141697) and the Flemish Fund for Scientific Research (FWO, 1500917N) for a PhD scholarship. The authors kindly acknowledge funding from KU Leuven through C16/17/005 and from the Belgian Federal Government through IAP 6/27 Functional Supramolecular systems. S.B. and M.P. acknowledge financial support from the European Research Council (ERC Starting Grant #335078-COLOURATOM). M.P. acknowledges funding from the European Union (ESTEEM2, No. 312483) and the HEiKA centre FunTECH-3D (Ministry of Science, Research and Art Baden-Wurttemberg, AZ: 33-753-30-20/3/3). The MLZ-Garching is kindly acknowledged for providing access to the NEPOMUC facilities (project no 11541). ; ecas_sara |
Approved |
Most recent IF: 6.035 |
Call Number |
UA @ lucian @ c:irua:153618UA @ admin @ c:irua:153618 |
Serial |
5132 |
Permanent link to this record |
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Author |
Yang, C.; Laberty-Robert, C.; Batuk, D.; Cibin, G.; Chadwick, A.V.; Pimenta, V.; Yin, W.; Zhang, L.; Tarascon, J.-M.; Grimaud, A. |
Title |
Phosphate ion functionalization of perovskite surfaces for enhanced oxygen evolution reaction |
Type |
A1 Journal article |
Year |
2017 |
Publication |
The journal of physical chemistry letters |
Abbreviated Journal |
J Phys Chem Lett |
Volume |
8 |
Issue |
15 |
Pages |
3466-3472 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
Recent findings revealed that surface oxygen can participate in the oxygen evolution reaction (OER) for the most active catalysts, which eventually triggers a new mechanism for which the deprotonation of surface intermediates limits the OER activity. We propose in this work a “dual strategy” in which tuning the electronic properties of the oxide, such as La1-xSrxCoO3-delta, can be dissociated from the use of surface functionalization with phosphate ion groups (P-i) that enhances the interfacial proton transfer. Results show that the P-i functionalized La0.5Sr0.5CoO3-delta gives rise to a significant enhancement of the OER activity when compared to La0.5Sr0.5Co3-delta and LaCoO3. We further demonstrate that the P-i surface functionalization selectivity enhances the activity when the OER kinetics is limited by the proton transfer. Finally, this work suggests that tuning the catalytic activity by such a “dual approach” may be a new and largely unexplored avenue for the design of novel high-performance catalysts. |
Address |
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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 |
Editor |
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Language |
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Wos |
000407191300003 |
Publication Date |
2017-07-07 |
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 |
1948-7185 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.353 |
Times cited |
31 |
Open Access |
OpenAccess |
Notes |
; C.Y., J.-M.T., D.B., and A.G. acknowledge funding from the European Research Council (ERC) (FP/2014)/ERC Grant-Project 670116-ARPEMA. We acknowledge Diamond Light Source for time awarded to the Energy Materials BAG on Beamline B18, under Proposal sp12559. ; |
Approved |
Most recent IF: 9.353 |
Call Number |
UA @ lucian @ c:irua:145730 |
Serial |
4747 |
Permanent link to this record |
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Author |
Çakir, D.; Peeters, F.M.; Sevik, C. |
Title |
Mechanical and thermal properties of h-MX2 (M = Cr, Mo, W; X = O, S, Se, Te) monolayers : a comparative study |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
Volume |
104 |
Issue |
20 |
Pages |
203110 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Using density functional theory, we obtain the mechanical and thermal properties of MX2 monolayers (where M = Cr, Mo, W and X = O, S, Se, Te). The C-centered phonon frequencies (i.e., A(1), A(2)'', E ', and E ''), relative frequency values of A(1), and E ' modes, and mechanical properties (i.e., elastic constants, Young modulus, and Poisson's ratio) display a strong dependence on the type of metal and chalcogenide atoms. In each chalcogenide (metal) group, transition-metal dichalcogenides (TMDCs) with W (O) atom are found to be much stiffer. Consistent with their stability, the thermal expansion of lattice constants for TMDCs with O (Te) is much slower (faster). Furthermore, in a heterostructure of these materials, the difference of the thermal expansion of lattice constants between the individual components becomes quite tiny over the whole temperature range. The calculated mechanical and thermal properties show that TMDCs are promising materials for heterostructures. (C) 2014 AIP Publishing LLC. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000337140800063 |
Publication Date |
2014-05-24 |
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 |
0003-6951;1077-3118; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.411 |
Times cited |
130 |
Open Access |
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Notes |
; Cem Sevik acknowledges the support from Scientific and Technological Research Council of Turkey (TUBITAK-113F096) and Anadolu University (BAP-1306F261 and -1306F281) to this project. We would also like to thank the ULAKBIM High Performance and Grid Computing Center for a generous time allocation for our projects. D. C. was supported by a FWO Pegasus-short Marie Curie Fellowship. Part of this work was supported by the Methusalem foundation of the Flemish Government. ; |
Approved |
Most recent IF: 3.411; 2014 IF: 3.302 |
Call Number |
UA @ lucian @ c:irua:118379 |
Serial |
1974 |
Permanent link to this record |
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Author |
Fedoseeva, Y.V.; Orekhov, A.S.; Chekhova, G.N.; Koroteev, V.O.; Kanygin, M.A.; Seovskiy, B.V.; Chuvilin, A.; Pontiroli, D.; Ricco, M.; Bulusheva, L.G.; Okotrub, A.V. |
Title |
Single-walled carbon nanotube reactor for redox transformation of mercury dichloride |
Type |
A1 Journal article |
Year |
2017 |
Publication |
ACS nano |
Abbreviated Journal |
Acs Nano |
Volume |
11 |
Issue |
9 |
Pages |
8643-8649 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
<script type='text/javascript'>document.write(unpmarked('Single-walled carbon nanotubes (SWCNTs) possessing a confined inner space protected by chemically resistant shells are promising for delivery, storage, and desorption of various compounds, as well as carrying out specific reactions. Here, we show that SWCNTs interact with molten mercury dichloride (HgCl2) and guide its transformation into dimercury dichloride (Hg2Cl2) in the cavity. The chemical state of host SWCNTs remains almost unchanged except for a small p-doping from the guest Hg2Cl2 nanocrystals. The density functional theory calculations reveal that the encapsulated HgCl2 molecules become negatively charged and start interacting via chlorine bridges when local concentration increases. This reduces the bonding strength in HgCl2, which facilitates removal of chlorine, finally leading to formation of Hg2Cl2 species. The present work demonstrates that SWCNTs not only serve as a template for growing nanocrystals but also behave as an electron-transfer catalyst in the spatially confined redox reaction by donation of electron density for temporary use by the guests.')); |
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 |
000411918200012 |
Publication Date |
2017-08-07 |
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 |
|
ISSN |
1936-0851 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
13.942 |
Times cited |
11 |
Open Access |
Not_Open_Access |
Notes |
; Collaboration between partner institutions was partially supported by European FP7 IRSES project 295180. We are grateful to the bilateral Program “Russian-German Laboratory at BESSY II” for the assistance in XPS and NEXAFS measurements. We acknowledge C. Tollan for proofreading the manuscript. We are grateful to Dr. Y.V. Shubin for XRD measurements of graphite with HgCl<INF>2</ INF>. ; |
Approved |
Most recent IF: 13.942 |
Call Number |
UA @ lucian @ c:irua:146770 |
Serial |
4895 |
Permanent link to this record |
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Author |
Yagmurcukardes, M.; Peeters, F.M. |
Title |
Stable single layer of Janus MoSO: strong out-of-plane piezoelectricity |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
Volume |
101 |
Issue |
15 |
Pages |
155205-155208 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Using density functional theory based first-principles calculations, we predict the dynamically stable 1H phase of a Janus single layer composed of S-Mo-O atomic layers. It is an indirect band gap semiconductor exhibiting strong polarization arising from the charge difference on the two surfaces. In contrast to 1H phases of MoS2 and MoO2, Janus MoSO is found to possess four Raman active phonon modes and a large out-of-plane piezoelectric coefficient which is absent in fully symmetric single layers of MoS2 and MoO2. We investigated the electronic and phononic properties under applied biaxial strain and found an electronic phase transition with tensile strain while the conduction band edge displays a shift when under compressive strain. Furthermore, single-layer MoSO exhibits phononic stability up to 5% of compressive and 11% of tensile strain with significant phonon shifts. The phonon instability is shown to arise from the soft in-plane and out-of-plane acoustic modes at finite wave vector. The large strain tolerance of Janus MoSO is important for nanoelastic applications. In view of the dynamical stability even under moderate strain, we expect that Janus MoSO can be fabricated in the common 1H phase with a strong out-of-plane piezoelectric coefficient. |
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 |
000528507900003 |
Publication Date |
2020-04-24 |
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 |
|
ISSN |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.7 |
Times cited |
66 |
Open Access |
|
Notes |
; Computational resources were provided by the Flemish Supercomputer Center (VSC). M.Y. is supported by the Flemish Science Foundation (FWO-Vl) through a postdoctoral fellowship. ; |
Approved |
Most recent IF: 3.7; 2020 IF: 3.836 |
Call Number |
UA @ admin @ c:irua:169566 |
Serial |
6614 |
Permanent link to this record |
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Author |
Siriwardane, E.M.D.; Demiroglu, I.; Sevik, C.; Peeters, F.M.; Çakir, D. |
Title |
Assessment of sulfur-functionalized MXenes for li-ion battery applications |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Journal Of Physical Chemistry C |
Abbreviated Journal |
J Phys Chem C |
Volume |
124 |
Issue |
39 |
Pages |
21293-21304 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
Abstract |
The surface termination of MXenes greatly determines the electrochemical properties and ion kinetics on their surfaces. So far, hydroxyl-, oxygen-, and fluorine-terminated MXenes have been widely studied for energy storage applications. Recently, sulfur-functionalized MXene structures, which possess low diffusion barriers, have been proposed as candidate materials to enhance battery performance. We performed first-principles calculations on the structural, stability, electrochemical, and ion dynamic properties of Li-adsorbed sulfur-functionalized groups 3B, 4B, 5B, and 6B transition-metal (M)-based MXenes (i.e., M2CS2 with M = Sc, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W). We performed phonon calculations, which indicated that all of the above M2CS2 MXenes, except for Sc, are dynamically stable at T = 0 K. The ground-state structure of each M2CS2 monolayer depends on the type of M atom. For instance, while sulfur prefers to sit at the FCC site on Ti2CS2, it occupies the HCP site of Cr-based MXene. We determined the Li adsorption configurations at different concentrations using the cluster expansion method. The highest maximum open-circuit voltages were computed for the group 4B element (i.e., Ti, Zr, and Hf)-based M2CS2, which are larger than 2.1 V, while their average voltages are approximately 1 V. The maximum voltage for the group 6B element (i.e., Cr, Mo, W)-based M2CS2 is less than 1 V, and the average voltage is less than 0.71 V. We found that S functionalization is helpful for capacity improvements over the O-terminated MXenes. In this respect, the computed storage gravimetric capacity may reach up to 417.4 mAh/g for Ti2CS2 and 404.5 mAh/g for V2CS2. Ta-, Cr-, Mo-, and W-based M2CS2 MXenes show very low capacities, which are less than 100 mAh/g. The Li surface diffusion energy barriers for all of the considered MXenes are less than 0.22 eV, which is favorable for high charging and discharging rates. Finally, ab initio molecular dynamic simulations performed at 400 K and bond-length analysis with respect to Li concentration verify that selected promising systems are robust against thermally induced perturbations that may induce structural transformations or distortions and undesirable Li release. |
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 |
000577151900008 |
Publication Date |
2020-09-01 |
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 |
1932-7447; 1932-7455 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.7 |
Times cited |
24 |
Open Access |
|
Notes |
; Computational resources were provided by the HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules Foundation. This work was supported, in part, by The Scientific and Technological Research Council of Turkey (TUBITAK) under contract no. 118F512 and the Air Force Office of Scientific Research under award no. FA9550-19-1-7048. This work was performed in part at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DE-AC02-06CH11357. This work was supported, in part, by The Scientific and Technological Research Council of Turkey (TUBITAK) under contract no. 118C026. ; |
Approved |
Most recent IF: 3.7; 2020 IF: 4.536 |
Call Number |
UA @ admin @ c:irua:172693 |
Serial |
6452 |
Permanent link to this record |
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Author |
Yagmurcukardes, M. |
Title |
Stable anisotropic single-layer of ReTe₂ : a first principles prediction |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Turkish Journal of Physics |
Abbreviated Journal |
|
Volume |
44 |
Issue |
5 |
Pages |
450-457 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
In order to investigate the structural, vibrational, electronic, and mechanical features of single-layer ReTe2 first-principles calculations are performed. Dynamical stability analyses reveal that single-layer ReTe2 crystallize in a distorted phase while its 1H and 1T phases are dynamically unstable. Raman spectrum calculations show that single-layer distorted phase of ReTe2 exhibits 18 Raman peaks similar to those of ReS2 and ReSe2. Electronically, single-layer ReTe2 is shown to be an indirect gap semiconductor with a suitable band gap for optoelectronic applications. In addition, it is found that the formation of Re-units in the crystal induces anisotropic mechanical parameters. The in-plane stiffness and Poisson ratio are shown to be significantly dependent on the lattice orientation. Our findings indicate that single-layer form of ReTe2 can only crystallize in a dynamically stable distorted phase formed by the Re-units. Single-layer of distorted ReTe2 can be a potential in-plane anisotropic material for various nanotechnology applications. |
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 |
000585330600004 |
Publication Date |
2020-09-20 |
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 |
1300-0101 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
|
Times cited |
|
Open Access |
|
Notes |
; Computational resources were provided by the Scientific and Technological Research Council of Turkey (TUBITAK) Turkish Academic Network and Information Center (ULAKBIM), High Performance and Grid Computing Center (TR-Grid e-Infrastructure) and by Flemish Supercomputer Center (VSC). This work was supported by the Flemish Science Foundation (FWO-Vl) by a postdoctoral fellowship (M.Y.). ; |
Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:174296 |
Serial |
6698 |
Permanent link to this record |
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Author |
Ceyhan, E.; Yagmurcukardes, M.; Peeters, F.M.; Sahin, H. |
Title |
Electronic and magnetic properties of single-layer FeCl₂ with defects |
Type |
A1 Journal article |
Year |
2021 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
Volume |
103 |
Issue |
1 |
Pages |
014106 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The formation of lattice defects and their effect on the electronic properties of single-layer FeCl2 are investigated by means of first-principles calculations. Among the vacancy defects, namely mono-, di-, and three-Cl vacancies and mono-Fe vacancy, the formation of mono-Cl vacancy is the most preferable. Comparison of two different antisite defects reveals that the formation of the Fe-antisite defect is energetically preferable to the Cl-antisite defect. While a single Cl vacancy leads to a 1 mu(B) decrease in the total magnetic moment of the host lattice, each Fe vacant site reduces the magnetic moment by 4 mu(B). However, adsorption of an excess Cl atom on the surface changes the electronic structure to a ferromagnetic metal or to a ferromagnetic semiconductor depending on the adsorption site without changing the ferromagnetic state of the host lattice. Both Cl-antisite and Fe-antisite defected domains change the magnetic moment of the host lattice by -1 mu(B) and +3 mu(B), respectively. The electronic ground state of defected structures reveals that (i) single-layer FeCl2 exhibits half-metallicity under the formation of vacancy and Cl-antisite defects; (ii) ferromagnetic metallicity is obtained when a single Cl atom is adsorbed on upper-Cl and Fe sites, respectively; and (iii) ferromagnetic semiconducting behavior is found when a Cl atom is adsorbed on a lower-Cl site or a Fe-antisite defect is formed. Simulated scanning electron microscope images show that atomic-scale identification of defect types is possible from their electronic charge density. Further investigation of the periodically Fe-defected structures reveals that the formation of the single-layer FeCl3 phase, which is a dynamically stable antiferromagnetic semiconductor, is possible. Our comprehensive analysis on defects in single-layer FeCl2 will complement forthcoming experimental observations. |
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 |
000606969400002 |
Publication Date |
2021-01-13 |
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 |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
7 |
Open Access |
Not_Open_Access |
Notes |
; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure), and by Flemish Supercomputer Center (VSC). H.S. acknowledges financial support from the Scientific and Technological Research Council of Turkey (TUBITAK) under Project No. 117F095. M.Y. was supported by the Flemish Science Foundation (FWO-Vl) by a postdoctoral fellowship. ; |
Approved |
Most recent IF: 3.836 |
Call Number |
UA @ admin @ c:irua:176039 |
Serial |
6689 |
Permanent link to this record |
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Author |
Iyikanat, F.; Yagmurcukardes, M.; Senger, R.T.; Sahin, H. |
Title |
Tuning electronic and magnetic properties of monolayer \alpha-RuCl3 by in-plane strain |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Journal of materials chemistry C : materials for optical and electronic devices |
Abbreviated Journal |
J Mater Chem C |
Volume |
6 |
Issue |
8 |
Pages |
2019-2025 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
By employing density functional theory-based methods, the structural, vibrational, electronic, and magnetic properties of monolayer -RuCl3 were investigated. It was demonstrated that ferromagnetic (FM) and zigzag-antiferromagnetic (ZZ-AFM) spin orders in the material have very close total energies with the latter being the ground state. We found that each Ru atom possesses a magnetic moment of 0.9 (B) and the material exhibits strong magnetic anisotropy. While both phases exhibit indirect gaps, the FM phase is a magnetic semiconductor and the ZZ-AFM phase is a non-magnetic semiconductor. The structural stability of the material was confirmed by phonon calculations. Moreover, dynamical analysis revealed that the magnetic order in the material can be monitored via Raman measurements of the crystal structure. In addition, the magnetic ground state of the material changes from ZZ-AFM to FM upon certain applied strains. Valence and conduction band-edges of the material vary considerably under in-plane strains. Owing to the stable lattice structure and unique and controllable magnetic properties, monolayer -RuCl3 is a promising material in nanoscale device applications. |
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 |
000426483800015 |
Publication Date |
2018-01-22 |
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 |
2050-7526; 2050-7534 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
5.256 |
Times cited |
16 |
Open Access |
|
Notes |
; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H. S. acknowledges financial support from TUBITAK under project number 116C073. H. S. also acknowledges support from Bilim Akademisi-The Science Academy, Turkey, under the BAGEP program. ; |
Approved |
Most recent IF: 5.256 |
Call Number |
UA @ lucian @ c:irua:149900UA @ admin @ c:irua:149900 |
Serial |
4952 |
Permanent link to this record |
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Author |
Yagmurcukardes, M.; Bacaksiz, C.; Unsal, E.; Akbali, B.; Senger, R.T.; Sahin, H. |
Title |
Strain mapping in single-layer two-dimensional crystals via Raman activity |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
Volume |
97 |
Issue |
11 |
Pages |
115427 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
By performing density functional theory-based ab initio calculations, Raman-active phonon modes of single-layer two-dimensional (2D) materials and the effect of in-plane biaxial strain on the peak frequencies and corresponding activities of the Raman-active modes are calculated. Our findings confirm the Raman spectrum of the unstrained 2D crystals and provide expected variations in the Raman-active modes of the crystals under in-plane biaxial strain. The results are summarized as follows: (i) frequencies of the phonon modes soften (harden) under applied tensile (compressive) strains; (ii) the response of the Raman activities to applied strain for the in-plane and out-of-plane vibrational modes have opposite trends, thus, the built-in strains in the materials can be monitored by tracking the relative activities of those modes; (iii) in particular, the A peak in single-layer Si and Ge disappears under a critical tensile strain; (iv) especially in mono-and diatomic single layers, the shift of the peak frequencies is a stronger indication of the strain rather than the change in Raman activities; (v) Raman-active modes of single-layer ReX2 (X = S, Se) are almost irresponsive to the applied strain. Strain-induced modifications in the Raman spectrum of 2D materials in terms of the peak positions and the relative Raman activities of the modes could be a convenient tool for characterization. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
American Physical Society |
Place of Publication |
New York, N.Y |
Editor |
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Language |
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Wos |
000427799300006 |
Publication Date |
2018-03-19 |
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 |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
21 |
Open Access |
|
Notes |
; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. acknowledges financial support from the Scientific and Technological Research Council of Turkey (TUBITAK) under Project No. 116C073. ; |
Approved |
Most recent IF: 3.836 |
Call Number |
UA @ lucian @ c:irua:150840UA @ admin @ c:irua:150840 |
Serial |
4979 |
Permanent link to this record |
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Author |
Yagmurcukardes, M.; Peeters, F.M.; Sahin, H. |
Title |
Electronic and vibrational properties of PbI2: From bulk to monolayer |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
Volume |
98 |
Issue |
8 |
Pages |
085431 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Using first-principles calculations, we study the dependence of the electronic and vibrational properties of multilayered PbI2 crystals on the number of layers and focus on the electronic-band structure and the Raman spectrum. Electronic-band structure calculations reveal that the direct or indirect semiconducting behavior of PbI2 is strongly influenced by the number of layers. We find that at 3L thickness there is a direct-to-indirect band gap transition (from bulk-to-monolayer). It is shown that in the Raman spectrum two prominent peaks, A(1g) and E-g, exhibit phonon hardening with an increasing number of layers due to the interlayer van der Waals interaction. Moreover, the Raman activity of the A(1g) mode significantly increases with an increasing number of layers due to the enhanced out-of-plane dielectric constant in the few-layer case. We further characterize rigid-layer vibrations of low-frequency interlayer shear (C) and breathing (LB) modes in few-layer PbI2. A reduced monatomic (linear) chain model (LCM) provides a fairly accurate picture of the number of layers dependence of the low-frequency modes and it is shown also to be a powerful tool to study the interlayer coupling strength in layered PbI2. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
American Physical Society |
Place of Publication |
New York, N.Y |
Editor |
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Language |
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Wos |
000442667200008 |
Publication Date |
2018-08-24 |
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 |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
41 |
Open Access |
|
Notes |
; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. acknowledges financial support from the Scientific and Technological Research Council of Turkey (TUBITAK) under Project No. 117F095. Part of this work was supported by FLAG-ERA project TRANS-2D-TMD. ; |
Approved |
Most recent IF: 3.836 |
Call Number |
UA @ lucian @ c:irua:153716UA @ admin @ c:irua:153716 |
Serial |
5097 |
Permanent link to this record |
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Author |
Yagmurcukardes, M.; Ozen, S.; Iyikanat, F.; Peeters, F.M.; Sahin, H. |
Title |
Raman fingerprint of stacking order in HfS2-Ca(OH)(2) heterobilayer |
Type |
A1 Journal article |
Year |
2019 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
Volume |
99 |
Issue |
20 |
Pages |
205405 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Using density functional theory-based first-principles calculations, we investigate the stacking order dependence of the electronic and vibrational properties of HfS2-Ca(OH)(2) heterobilayer structures. It is shown that while the different stacking types exhibit similar electronic and optical properties, they are distinguishable from each other in terms of their vibrational properties. Our findings on the vibrational properties are the following: (i) from the interlayer shear (SM) and layer breathing (LBM) modes we are able to deduce the AB' stacking order, (ii) in addition, the AB' stacking type can also be identified via the phonon softening of E-g(I) and A(g)(III) modes which harden in the other two stacking types, and (iii) importantly, the ultrahigh frequency regime possesses distinctive properties from which we can distinguish between all stacking types. Moreover, the differences in optical and vibrational properties of various stacking types are driven by two physical effects, induced biaxial strain on the layers and the layer-layer interaction. Our results reveal that with both the phonon frequencies and corresponding activities, the Raman spectrum possesses distinctive properties for monitoring the stacking type in novel vertical heterostructures constructed by alkaline-earth-metal hydroxides. |
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 |
000467387800010 |
Publication Date |
2019-05-06 |
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 |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
27 |
Open Access |
|
Notes |
; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. acknowledges financial support from the Scientific and Technological Research Council of Turkey (TUBITAK) under the Project No. 117F095. H.S. acknowledges support from Turkish Academy of Sciences under the GEBIP program. This work is supported by the Flemish Science Foundation (FWO-Vl) by a postdoctoral fellowship (M.Y.). ; |
Approved |
Most recent IF: 3.836 |
Call Number |
UA @ admin @ c:irua:160334 |
Serial |
5226 |
Permanent link to this record |
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Author |
Baskurt, M.; Yagmurcukardes, M.; Peeters, F.M.; Sahin, H. |
Title |
Stable single-layers of calcium halides (CaX₂, X = F, Cl, Br, I) |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Journal Of Chemical Physics |
Abbreviated Journal |
J Chem Phys |
Volume |
152 |
Issue |
16 |
Pages |
164116-164118 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
By means of density functional theory based first-principles calculations, the structural, vibrational, and electronic properties of 1H- and 1T-phases of single-layer CaX2 (X = F, Cl, Br, or I) structures are investigated. Our results reveal that both the 1H- and 1T-phases are dynamically stable in terms of their phonon band dispersions with the latter being the energetically favorable phase for all single-layers. In both phases of single-layer CaX2 structures, significant phonon softening occurs as the atomic radius increases. In addition, each structural phase exhibits distinctive Raman active modes that enable one to characterize either the phase or the structure via Raman spectroscopy. The electronic band dispersions of single-layer CaX2 structures reveal that all structures are indirect bandgap insulators with a decrease in bandgaps from fluorite to iodide crystals. Furthermore, the calculated linear elastic constants, in-plane stiffness, and Poisson ratio indicate the ultra-soft nature of CaX2 single-layers, which is quite important for their nanoelastic applications. Overall, our study reveals that with their dynamically stable 1T- and 1H-phases, single-layers of CaX2 crystals can be alternative ultra-thin insulators. |
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 |
000531819100001 |
Publication Date |
2020-04-29 |
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 |
0021-9606 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.4 |
Times cited |
14 |
Open Access |
|
Notes |
; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. acknowledges financial support from the TUBITAK under Project No. 117F095. H.S. acknowledges support from the Turkish Academy of Sciences under the GEBIP program. M.Y. was supported by a postdoctoral fellowship from the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 4.4; 2020 IF: 2.965 |
Call Number |
UA @ admin @ c:irua:169543 |
Serial |
6615 |
Permanent link to this record |
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Author |
Kahraman, Z.; Yagmurcukardes, M.; Sahin, H. |
Title |
Functionalization of single-layer TaS₂ and formation of ultrathin Janus structures |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Journal Of Materials Research |
Abbreviated Journal |
J Mater Res |
Volume |
35 |
Issue |
11 |
Pages |
1397-1406 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Ab initio calculations are performed to investigate the structural, vibrational, electronic, and piezoelectric properties of functionalized single layers of TaS2. We find that single-layer TaS2 is a suitable host material for functionalization via fluorination and hydrogenation. The one-side fluorinated (FTaS2) and hydrogenated (HTaS2) single layers display indirect gap semiconducting behavior in contrast to bare metallic TaS2. On the other hand, it is shown that as both surfaces of TaS2 are saturated anti-symmetrically, the formed Janus structure is a dynamically stable metallic single layer. In addition, it is revealed that out-of-plane piezoelectricity is created in all anti-symmetric structures. Furthermore, the Janus-type single-layer has the highest specific heat capacity to which longitudinal and transverse acoustical phonon modes have contribution at low temperatures. Our findings indicate that single-layer TaS2 is suitable for functionalization via H and F atoms that the formed, anti-symmetric structures display distinctive electronic, vibrational, and piezoelectric properties. |
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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 |
000540764300005 |
Publication Date |
2020-04-08 |
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 |
0884-2914 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.7 |
Times cited |
1 |
Open Access |
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Notes |
; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. Acknowledges financial support from the TUBITAK under the project number 117F095. H.S. acknowledges support from Turkish Academy of Sciences under the GEBIP program. This work is supported by the Flemish Science Foundation (FWO-Vl) by a post-doctoral fellowship (M.Y.). ; |
Approved |
Most recent IF: 2.7; 2020 IF: 1.673 |
Call Number |
UA @ admin @ c:irua:170185 |
Serial |
6525 |
Permanent link to this record |