Records |
Author |
Brodu, A.; Ballottin, M.V.; Buhot, J.; van Harten, E.J.; Dupont, D.; La Porta, A.; Prins, P.T.; Tessier, M.D.; Versteegh, M.A.M.; Zwiller, V.; Bals, S.; Hens, Z.; Rabouw, F.T.; Christianen, P.C.M.; de Donega, C.M.; Vanmaekelbergh, D. |
Title |
Exciton Fine Structure and Lattice Dynamics in InP/ZnSe Core/Shell Quantum Dots |
Type |
A1 Journal article |
Year |
2018 |
Publication |
ACS Photonics |
Abbreviated Journal |
Acs Photonics |
Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
5 |
Issue |
5 |
Pages |
3353-3362 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
Nanocrystalline InP quantum dots (QDs) hold promise for heavy-metal-free optoelectronic applications due to their bright and size tunable emission in the visible range. Photochemical stability and high photoluminescence (PL) quantum yield are obtained by a diversity of epitaxial shells around the InP core. To understand and optimize the emission line shapes, the exciton fine structure of InP core/shell QD systems needs be investigated. Here, we study the exciton fine structure of InP/ZnSe core/shell QDs with core diameters ranging from 2.9 to 3.6 nm (PL peak from 2.3 to 1.95 eV at 4 K). PL decay measurements as a function of temperature in the 10 mK to 300 K range show that the lowest exciton fine structure state is a dark state, from which radiative recombination is assisted by coupling to confined acoustic phonons with energies ranging from 4 to 7 meV, depending on the core diameter. Circularly polarized fluorescence line-narrowing (FLN) spectroscopy at 4 K under high magnetic fields (up to 30 T) demonstrates that radiative recombination from the dark F = +/- 2 state involves acoustic and optical phonons, from both the InP core and the ZnSe shell. Our data indicate that the highest intensity FLN peak is an acoustic phonon replica rather than a zero-phonon line, implying that the energy separation observed between the F = +/- 1 state and the highest intensity peak in the FLN spectra (6 to 16 meV, depending on the InP core size) is larger than the splitting between the dark and bright fine structure exciton states. |
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 |
000442185900049 |
Publication Date |
2018-07-18 |
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 |
2330-4022 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.756 |
Times cited |
40 |
Open Access |
OpenAccess |
Notes |
; We acknowledge the support of the HFML-RU/FOM, member of the European Magnetic Field Laboratory (EMFL). D.V. and Z.H. acknowledge support by the European Commission via the Marie-Sklodowska Curie action Phonsi (H2020-MSCA-ITN-642656) and the Marie Sklodowska-Curie Action Compass (H2020 MSCA-RISE-691185). Z.H. acknowledges the Research Foundation Flanders (project 17006602) and Ghent University (GOA no. 01G01513). Z.H. and S.B. acknowledge SIM vzw (SBO-QDOCCO). F.T.R. acknowledges financial support from The Netherlands Organisation for Scientific Research NWO (Gravitation program Multiscale Catalytic Energy Conversion and VENI grant number 722.017.002). This work was also supported by the Dutch NWO-Physics Program DDC13, ERC Advanced Grant 692691 “First step”, and ERC Starting Grant 335078 “COLOURATOM”. ; ecas_sara |
Approved |
Most recent IF: 6.756 |
Call Number |
UA @ lucian @ c:irua:153753UA @ admin @ c:irua:153753 |
Serial |
5100 |
Permanent link to this record |
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Author |
Leemans, J.; Singh, S.; Li, C.; Ten Brinck, S.; Bals, S.; Infante, I.; Moreels, I.; Hens, Z. |
Title |
Near-Edge Ligand Stripping and Robust Radiative Exciton Recombination in CdSe/CdS Core/Crown Nanoplatelets |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Journal Of Physical Chemistry Letters |
Abbreviated Journal |
J Phys Chem Lett |
Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
11 |
Issue |
9 |
Pages |
3339-3344 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
We address the relation between surface chemistry and optoelectronic properties in semiconductor nanocrystals using core/crown CdSe/CdS nanoplatelets passivated by cadmium oleate (Cd(Ol)2) as model systems. We show that addition of butylamine to a nanoplatelet (NPL) dispersion maximally displaces ∼40% of the original Cd(Ol)2 capping. On the basis of density functional theory simulations, we argue that this behavior reflects the preferential displacement of Cd(Ol)2 from (near)-edge surface sites. Opposite from CdSe core NPLs, core/crown NPL dispersions can retain 45% of their initial photoluminescence efficiency after ligand displacement, while radiative exciton recombination keeps dominating the luminescent decay. Using electron microscopy observations, we assign this robust photoluminescence to NPLs with a complete CdS crown, which prevents charge carrier trapping in the near-edge surface sites created by ligand displacement. We conclude that Z-type ligands such as cadmium carboxylates can provide full electronic passivation of (100) facets yet are prone to displacement from (near)-edge surface sites. |
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 |
000535177500024 |
Publication Date |
2020-05-07 |
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 |
1948-7185 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
5.7 |
Times cited |
24 |
Open Access |
OpenAccess |
Notes |
Universiteit Gent, GOA 01G01019 ; Fonds Wetenschappelijk Onderzoek, 17006602 FWO17/PDO/184 ; H2020 European Research Council, 714876 Phocona 815128 Realnano ; SIM-Flanders, SBO-QDOCCO ; Z.H. and S.B. acknowledge support by SIM-Flanders (SBO-QDOCCO). Z.H. acknowledges support by FWO-Vlaanderen (research project 17006602). Z.H. and I.M. acknowledge support by Ghent University (GOA n◦ 01G01019). J.L. acknowledges FWO-vlaanderen for a fellowship (SB PhD fellow at FWO). Sh.S acknowledges FWO postdoctoral funding (FWO17/PDO/184). This project has further received funding from the European Research Counsil under the European Union’s Horizon 2020 research and innovation programme (ERC Consolidator grant no. 815128 REALNANO and starting grant no. 714876 PHOCONA).; sygma |
Approved |
Most recent IF: 5.7; 2020 IF: 9.353 |
Call Number |
EMAT @ emat @c:irua:173994 |
Serial |
6657 |
Permanent link to this record |
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Author |
Locardi, F.; Samoli, M.; Martinelli, A.; Erdem, O.; Vale Magalhaes, D.; Bals, S.; Hens, Z. |
Title |
Cyan emission in two-dimensional colloidal Cs2CdCl4:SB3+ Ruddlesden-Popper phase nanoplatelets |
Type |
A1 Journal article |
Year |
2021 |
Publication |
Acs Nano |
Abbreviated Journal |
Acs Nano |
Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
15 |
Issue |
11 |
Pages |
17729-17737 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
Metal halide perovskites are one of the most investigated materials in optoelectronics, with their lead-based counterparts being renowned for their enhanced optoelectronic performance. The 3D CsPbX3 structure has set the standard with many studies currently attempting to substitute lead with other metals while retaining the properties of this material. This effort has led to the fabrication of metal halides with lower dimensionality, wherein particular 2D layered perovskite structures have captured attention as inspiration for the next generation of colloidal semiconductors. Here we report the synthesis of the Ruddlesden-Popper Cs2CdCl4:Sb3+ phase as colloidal nanoplatelets (NPs) using a facile hot injection approach under atmospheric conditions. Through strict adjustment of the synthesis parameters with emphasis on the ligand ratio, we obtained NPs with a relatively uniform size and good morphological control. The particles were characterized through transmission electron microscopy, synchrotron X-ray diffraction, and pair distribution function analysis. The spectroscopic characterization revealed most strikingly an intense cyan emission under UV excitation with a measured PLQY of similar to 20%. The emission was attributed to the Sb3+-doping within the structure. |
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 |
000747115200053 |
Publication Date |
0000-00-00 |
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 |
1936-0851 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
13.942 |
Times cited |
34 |
Open Access |
OpenAccess |
Notes |
The authors acknowledge the European Synchrotron Radiation Facility for provision of synchrotron radiation facilities and they would like to thank Andrew Fitch for assistance in using beamline ID22 (proposal HC-4098). Z.H. and S.B acknowledge funding from the Research Foundation − Flanders (FWO-Vlaanderen under the SBO − PROCEED project (No: S0002019N). Z.H. acknowledges Ghent University for funding (BOF-GOA 01G01019). S.B. is grateful to the European Research Council (ERC Consolidator Grant 815128, REALNANO). F.L. thanks Emanuela Sartori and Stefano Toso for the fruitful discussions. M.S. would like to thank Olivier Janssens for collecting XRPD data and Gabriele Pippia for helpful insights and discussions. |
Approved |
Most recent IF: 13.942 |
Call Number |
UA @ admin @ c:irua:186465 |
Serial |
7059 |
Permanent link to this record |
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Author |
Casavola, M.; van Huis, M.A.; Bals, S.; Lambert, K.; Hens, Z.; Vanmaekelbergh, D. |
Title |
Anisotropic cation exchange in PbSe/CdSe core/shell nanocrystals of different geometry |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
24 |
Issue |
2 |
Pages |
294-302 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
We present a study of Cd2+-for-Pb2+ exchange in PbSe nanocrystals (NCs) with cube, star, and rod shapes. Prolonged temperature-activated cation exchange results in PbSe/CdSe heterostructured nanocrystals (HNCs) that preserve their specific overall shape, whereas the PbSe core is strongly faceted with dominance of {111} facets. Hence, cation exchange proceeds while the Se anion lattice is preserved, and well-defined {111}/{111} PbSe/CdSe interfaces develop. Interestingly, by quenching the reaction at different stages of the cation exchange new structures have been isolated, such as coreshell nanorods, CdSe rods that contain one or two separated PbSe dots and fully zinc blende CdSe nanorods. The crystallographically anisotropic cation exchange has been characterized by a combined HRTEM/HAADF-STEM study of heterointerface evolution over reaction time and temperature. Strikingly, Pb and Cd are only intermixed at the PbSe/CdSe interface. We propose a plausible model for the cation exchange based on a layer-by-layer replacement of Pb2+ by Cd2+ enabled by a vacancy-assisted cation migration mechanism. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000299367500008 |
Publication Date |
2011-11-17 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
136 |
Open Access |
|
Notes |
Esteem 026019 |
Approved |
Most recent IF: 9.466; 2012 IF: 8.238 |
Call Number |
UA @ lucian @ c:irua:94211 |
Serial |
124 |
Permanent link to this record |
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Author |
Tessier, M.D.; Baquero, E.A.; Dupont, D.; Grigel, V.; Bladt, E.; Bals, S.; Coppel, Y.; Hens, Z.; Nayral, C.; Delpech, F. |
Title |
Interfacial oxidation and photoluminescence of InP-Based core/shell quantum dots |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
30 |
Issue |
30 |
Pages |
6877-6883 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Indium phosphide colloidal quantum dots (QDs) are emerging as an efficient cadmium-free alternative for optoelectronic applications. Recently, syntheses based on easy-to-implement aminophosphine precursors have been developed. We show by solid-state nuclear magnetic resonance spectroscopy that this new approach allows oxide-free indium phosphide core or core/shell quantum dots to be made. Importantly, the oxide-free core/shell interface does not help in achieving higher luminescence efficiencies. We demonstrate that in the case of InP/ZnS and InP/ZnSe QDs, a more pronounced oxidation concurs with a higher photoluminescence efficiency. This study suggests that a II-VI shell on a III-V core generates an interface prone to defects. The most efficient InP/ZnS or InP/ZnSe QDs are therefore made with an oxide buffer layer between the core and the shell: it passivates these interface defects but also results in a somewhat broader emission line width. |
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 |
000447237800031 |
Publication Date |
2018-09-12 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
74 |
Open Access |
OpenAccess |
Notes |
; The authors thank L. Biadala and C. Delerue for fruitful discussion. Z.H. acknowledges support by the European Commission via the Marie-Sklodowska Curie action Phonsi (H2020-MSCA-ITN-642656), by Research Foundation Flanders (Project 17006602), and by Ghent University (GOA No. 01G01513). Z.H., M.D.T., and D.D. acknowledge the Strategisch Initiatief Materialen in Vlaanderen of Agentschap Innoveren en Ondernemen (SIM VLAIO), vzw (SBO-QDOCCO, ICON-QUALIDI). This work was supported by the Universite Paul Sabatier, the Region Midi-Pyrenees, the CNRS, the Institut National des Sciences Appliquees of Toulouse, and the Agence Nationale pour la Recherche (Project ANR-13-IS10-0004-01). E.A.B. is grateful to Marie Curie Actions and Campus France for a PRESTIGE postdoc fellowship (FP7 /2007-2013) under REA Grant Agreement PCOFUND-GA-2013-609102. E.B. acknowledges financial support from Research Foundation Flanders (FWO). ; |
Approved |
Most recent IF: 9.466 |
Call Number |
UA @ lucian @ c:irua:154732UA @ admin @ c:irua:154732 |
Serial |
5109 |
Permanent link to this record |
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Author |
Justo, Y.; Goris, B.; Sundar Kamal, J.; Geiregat, P.; Bals, S.; Hens, Z. |
Title |
Multiple dot-in-rod PbS/CdS heterostructures with high photoluminescence quantum yield in the near-infrared |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Journal of the American Chemical Society |
Abbreviated Journal |
J Am Chem Soc |
Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
134 |
Issue |
12 |
Pages |
5484-5487 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Pb cations in PbS quantum rods made from CdS quantum rods by successive complete cationic exchange reactions are partially re-exchanged for Cd cations. Using STEM-HAADF, we show that this leads to the formation of unique multiple dot-in-rod PbS/CdS heteronanostructures, with a photoluminescence quantum yield of 4555%. We argue that the formation of multiple dot-in-rods is related to the initial polycrystallinity of the PbS quantum rods, where each PbS crystallite transforms in a separate PbS/CdS dot-in-dot. Effective mass modeling indicates that electronic coupling between the different PbS conduction band states is feasible for the multiple dot-in-rod geometries obtained, while the hole states remain largely uncoupled. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000302489500015 |
Publication Date |
2012-03-16 |
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 |
0002-7863;1520-5126; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
13.858 |
Times cited |
41 |
Open Access |
|
Notes |
Fwo; Iap |
Approved |
Most recent IF: 13.858; 2012 IF: 10.677 |
Call Number |
UA @ lucian @ c:irua:96957 |
Serial |
2226 |
Permanent link to this record |