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Author Guttmann, P.; Bittencourt, C.; Ke, X.; Van Tendeloo, G.; Umek, P.; Arcon, D.; Ewels, C.P.; Rehbein, S.; Heim, S.; Schneider, G. pdf  url
doi  openurl
  Title TXM-NEXAFS of TiO2-based nanostructures Type P1 Proceeding
  Year 2011 Publication AIP conference proceedings Abbreviated Journal  
  Volume 1365 Issue Pages 437-440  
  Keywords (down) P1 Proceeding; Electron microscopy for materials research (EMAT)  
  Abstract In this work, electronic properties of individual TiOx-pristine nanoribbons (NR) prepared by hydrothermal treatment of anatase TiO(2) micro-particles were studied using the HZB transmission x-ray microscope (TXM) at the BESSY II undulator beamline U41-FSGM. NEXAFS is ideally suited to study TiO(2)-based materials because both the O K-edge and Ti L-edge features are very sensitive to the local bonding environment, providing diagnostic information about the crystal structures and oxidation states of various forms of titanium oxides and sub-oxides. TXM-NEXAFS combines full-field x-ray microscopy with spectroscopy, allowing the study of the electronic structure of individual nanostructures with spatial resolution better than 25 nm and a spectral resolution of up to E/Delta E = 10000. The typical image field in TXM-NEXAFS measurements is about 10 mu m. 10 mu m, which is large compared to the individual nanoparticle. Therefore, one image stack already contains statistically significant data. In addition, the directional electric field vector ((E) over bar) of the x-rays can be used as a “search tool” for the direction of chemical bonds of the atom selected by its absorption edge.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication New York Editor  
  Language Wos 000298672400103 Publication Date 2011-09-19  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited 2 Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:113071 Serial 3789  
Permanent link to this record
 

 
Author Ke, X. openurl 
  Title From top-down to bottom-up : from carbon nanotubes to nanodevices Type Doctoral thesis
  Year 2010 Publication Abbreviated Journal  
  Volume Issue Pages  
  Keywords (down) Doctoral thesis; Electron microscopy for materials research (EMAT)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Antwerpen Editor  
  Language Wos Publication Date 0000-00-00  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:87408 Serial 1289  
Permanent link to this record
 

 
Author Ribbens, S.; Beyers, E.; Schellens, K.; Mertens, M.; Ke, X.; Bals, S.; Van Tendeloo, G.; Meynen, V.; Cool, P. pdf  doi
openurl 
  Title Systematic evaluation of thermal and mechanical stability of different commercial and synthetic photocatalysts in relation to their photocatalytic activity Type A1 Journal article
  Year 2012 Publication Microporous and mesoporous materials: zeolites, clays, carbons and related materials Abbreviated Journal Micropor Mesopor Mat  
  Volume 156 Issue Pages 62-72  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)  
  Abstract The effect of thermal treatment and mechanical stress on the structural and photocatalytic properties of eight different (synthetic and commercial) photocatalysts has been thoroughly investigated. Different mesoporous Ti-based materials were prepared via surfactant based synthesis routes (e.g. Pluronic 123, CTMABr = Cetyltrimethylammonium bromide) or via template-free synthesis routes (e.g. trititanate nanotubes). Also, the stabilizing effect of the NaOH/NH4OH post-treatment on the templated mesoporous materials and their photocatalytic activity was investigated. Furthermore, the thermal and mechanical properties of commercially available titanium dioxides such as P25 Evonik® and Millenium PC500® were studied. The various photocatalysts were analyzed with N2-sorption, X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) to obtain information concerning the specific surface area, pore volume, crystal structure, morphology, phase transitions, etc. In general, results show that the NaOH post-treatment leads to an increased control of the crystallization process during calcination resulting in a higher thermal stability, but at the same time diminishes the photocatalytic activity. Mesoporous materials in which pre-synthesized nanoparticles are used as titania source have the best mechanical stability whereas the mechanical stability of the nanotubes is the most limited. At increased temperatures and pressures, the tested commercial titanium dioxides lose their superior photocatalytic activity caused by a decreased accessibility of the active sites. The observed changes in adsorption capacities and photocatalytic activities cannot be assigned to one single phenomenon. In this respect, it shows the need to define a general/standard method to compare different photocatalysts. Furthermore, it is shown that the photocatalytic properties do not necessarily deteriorate under thermal stress, but can be improved due to crystallization, even though the initial material is (partially) destroyed. It is shown that the usefulness of a specific type of photocatalyst strongly depends on the application and the temperature/pressure to which it needs to resist.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000303625200010 Publication Date 2012-02-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1387-1811; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.615 Times cited 8 Open Access  
  Notes Fwo Approved Most recent IF: 3.615; 2012 IF: 3.365  
  Call Number UA @ lucian @ c:irua:96910 Serial 3466  
Permanent link to this record
 

 
Author Llobet, E.; Espinosa, E.H.; Sotter, E.; Ionescu, R.; Vilanova, X.; Torres, J.; Felten, A.; Pireaux, J.J.; Ke, X.; Van Tendeloo, G.; Renaux, F.; Paint, Y.; Hecq, M.; Bittencourt, C.; pdf  doi
openurl 
  Title Carbon nanotube TiO2 hybrid films for detecting traces of O2 Type A1 Journal article
  Year 2008 Publication Nanotechnology Abbreviated Journal Nanotechnology  
  Volume 19 Issue 37 Pages 375501-375511  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Hybrid titania films have been prepared using an adapted sol-gel method for obtaining well-dispersed hydrogen plasma-treated multiwall carbon nanotubes in either pure titania or Nb-doped titania. The drop-coating method has been used to fabricate resistive oxygen sensors based on titania or on titania and carbon nanotube hybrids. Morphology and composition studies have revealed that the dispersion of low amounts of carbon nanotubes within the titania matrix does not significantly alter its crystallization behaviour. The gas sensitivity studies performed on the different samples have shown that the hybrid layers based on titania and carbon nanotubes possess an unprecedented responsiveness towards oxygen (i.e. more than four times higher than that shown by optimized Nb-doped TiO(2) films). Furthermore, hybrid sensors containing carbon nanotubes respond at significantly lower operating temperatures than their non-hybrid counterparts. These new hybrid sensors show a strong potential for monitoring traces of oxygen (i.e. <= 10 ppm) in a flow of CO(2), which is of interest for the beverage industry.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Bristol Editor  
  Language Wos 000258385600014 Publication Date 2008-08-02  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0957-4484;1361-6528; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.44 Times cited 48 Open Access  
  Notes Pai Approved Most recent IF: 3.44; 2008 IF: 3.446  
  Call Number UA @ lucian @ c:irua:103083 Serial 282  
Permanent link to this record
 

 
Author Bertoni, G.; Grillo, V.; Brescia, R.; Ke, X.; Bals, S.; Catellani, A.; Li, H.; Manna, L. doi  openurl
  Title Direct determination of polarity, faceting, and core location in colloidal core/shell wurtzite semiconductor nanocrystals Type A1 Journal article
  Year 2012 Publication ACS nano Abbreviated Journal Acs Nano  
  Volume 6 Issue 7 Pages 6453-6461  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract The ability to determine the atomic arrangement and termination of various facets of surfactant-coated nanocrystals is of great importance for understanding their growth mechanism and their surface properties and represents a critical piece of information that can be coupled to other experimental techniques and to calculations. This is especially appealing in the study of nanocrystals that can be grown in strongly anisotropic shapes, for which the relative growth rates of various facets can be influenced under varying reaction conditions. Here we show that in two representative cases of rod-shaped nanocrystals in the wurtzite phase (CdSe(core)/CdS(shell) and ZnSe(core)/ZnS(shell) nanorods) the terminations of the polar facets can be resolved unambiguously by combining advanced electron microscopy techniques, such as aberration-corrected HRTEM with exit wave reconstruction or aberration-corrected HAADF-STEM. The [0001] and [000-1] polar directions of these rods, which grow preferentially along their c-axis, are revealed clearly, with one side consisting of the Cd (or Zn)-terminated (0001) facet and the other side with a pronounced faceting due to Cd (or Zn)-terminated {10-1-1} facets. The lateral faceting of the rods is instead dominated by three nonpolar {10-10} facets. The core buried in the nanostructure can be localized in both the exit wave phase and HAADF-STEM images.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000306673800079 Publication Date 2012-06-18  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 13.942 Times cited 63 Open Access  
  Notes The authors gratefully acknowledge funding from the European Research Council under grant number 240111 (NANO-ARCH) and the financial support from the Flemish Hercules 3 Programme for large infrastructures. G.B. and V.G. thank E. Rotunno for his help with STEM_CELL and IWFR. Approved Most recent IF: 13.942; 2012 IF: 12.062  
  Call Number UA @ lucian @ c:irua:101138 Serial 710  
Permanent link to this record
 

 
Author Ke, X.; Turner, S.; Quintana, M.; Hadad, C.; Montellano-López, A.; Carraro, M.; Sartorel, A.; Bonchio, M.; Prato, M.; Bittencourt, C.; Van Tendeloo, G.; pdf  doi
openurl 
  Title Dynamic motion of Ru-polyoxometalate ions (POMs) on functionalized few-layer graphene Type A1 Journal article
  Year 2013 Publication Small Abbreviated Journal Small  
  Volume 9 Issue 23 Pages 3922-3927  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract The interaction and stability of Ru4POM on few layer graphene via functional groups is investigated by time-dependent imaging using aberration-corrected transmission electron microscopy. The Ru4POM demonstrates dynamic motion on the graphene surface with its frequency and amplitude of rotation related to the nature of the functional group used. The stability of the Ru4POMgraphene hybrid corroborates its long-term robustness when applied to multielectronic catalytic processes.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Weinheim Editor  
  Language Wos 000331282400003 Publication Date 2013-07-01  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1613-6810; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 8.643 Times cited 16 Open Access  
  Notes IAP-7; Countatoms; Approved Most recent IF: 8.643; 2013 IF: 7.514  
  Call Number UA @ lucian @ c:irua:115768 Serial 763  
Permanent link to this record
 

 
Author Schulze, A.; Hantschel, T.; Dathe, A.; Eyben, P.; Ke, X.; Vandervorst, W. pdf  doi
openurl 
  Title Electrical tomography using atomic force microscopy and its application towards carbon nanotube-based interconnects Type A1 Journal article
  Year 2012 Publication Nanotechnology Abbreviated Journal Nanotechnology  
  Volume 23 Issue 30 Pages 305707  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract The fabrication and integration of low-resistance carbon nanotubes (CNTs) for interconnects in future integrated circuits requires characterization techniques providing structural and electrical information at the nanometer scale. In this paper we present a slice-and-view approach based on electrical atomic force microscopy. Material removal achieved by successive scanning using doped ultra-sharp full-diamond probes, manufactured in-house, enables us to acquire two-dimensional (2D) resistance maps originating from different depths (equivalently different CNT lengths) on CNT-based interconnects. Stacking and interpolating these 2D resistance maps results in a three-dimensional (3D) representation (tomogram). This allows insight from a structural (e.g. size, density, distribution, straightness) and electrical point of view simultaneously. By extracting the resistance evolution over the length of an individual CNT we derive quantitative information about the resistivity and the contact resistance between the CNT and bottom electrode.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Bristol Editor  
  Language Wos 000306333500029 Publication Date 2012-07-11  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0957-4484;1361-6528; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.44 Times cited 29 Open Access  
  Notes Approved Most recent IF: 3.44; 2012 IF: 3.842  
  Call Number UA @ lucian @ c:irua:100750 Serial 895  
Permanent link to this record
 

 
Author Vidick, D.; Ke, X.; Devillers, M.; Poleunis, C.; Delcorte, A.; Moggi, P.; Van Tendeloo, G.; Hermans, S. pdf  url
doi  openurl
  Title Heterometal nanoparticles from Ru-based molecular clusters covalently anchored onto functionalized carbon nanotubes and nanofibers Type A1 Journal article
  Year 2015 Publication Beilstein journal of nanotechnology Abbreviated Journal Beilstein J Nanotech  
  Volume 6 Issue 6 Pages 1287-1297  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Heterometal clusters containing Ru and Au, Co and/or Pt are anchored onto carbon nanotubes and nanofibers functionalized with chelating phosphine groups. The cluster anchoring yield is related to the amount of phosphine groups available on the nanocarbon surface. The ligands of the anchored molecular species are then removed by gentle thermal treatment in order to form nanoparticles. In the case of Au-containing clusters, removal of gold atoms from the clusters and agglomeration leads to a bimodal distribution of nanoparticles at the nanocarbon surface. In the case of Ru-Pt species, anchoring occurs without reorganization through a ligand exchange mechanism. After thermal treatment, ultrasmall (1-3 nm) bimetal Ru-Pt nanoparticles are formed on the surface of the nanocarbons. Characterization by high resolution transmission electron microscopy (HRTEM) and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) confirms their bimetal nature on the nanoscale. The obtained bimetal nanoparticles supported on nanocarbon were tested as catalysts in ammonia synthesis and are shown to be active at low temperature and atmospheric pressure with very low Ru loading.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000355908400001 Publication Date 2015-06-10  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2190-4286; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.127 Times cited 7 Open Access  
  Notes 246791 Countatoms; 262348 Esmi Approved Most recent IF: 3.127; 2015 IF: 2.670  
  Call Number c:irua:126431 Serial 1420  
Permanent link to this record
 

 
Author Yan, Y.; Wang, L.-X.; Ke, X.; Van Tendeloo, G.; Wu, X.-S.; Yu, D.-P.; Liao, Z.-M. pdf  url
doi  openurl
  Title High-mobility Bi2Se3 nanoplates manifesting quantum oscillations of surface states in the sidewalls Type A1 Journal article
  Year 2014 Publication Scientific reports Abbreviated Journal Sci Rep-Uk  
  Volume 4 Issue Pages 3817-7  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Magnetotransport measurements of topological insulators are very important to reveal the exotic topological surface states for spintronic applications. However, the novel properties related to the surface Dirac fermions are usually accompanied by a large linear magnetoresistance under perpendicular magnetic field, which makes the identification of the surface states obscure. Here, we report prominent Shubnikov-de Haas (SdH) oscillations under an in-plane magnetic field, which are identified to originate from the surface states in the sidewalls of topological insulator Bi2Se3 nanoplates. Importantly, the SdH oscillations appear with a dramatically weakened magnetoresistance background, offering an easy path to probe the surface states directly when the coexistence of surface states and bulk conduction is inevitable. Moreover, under a perpendicular magnetic field, the oscillations in Hall conductivity have peak-to-valley amplitudes of 2 e(2)/h, giving confidence to achieve a quantum Hall effect in this system. A cross-section view of the nanoplate shows that the sidewall is (015) facet dominant and therefore forms a 586 angle with regard to the top/ bottom surface instead of being perpendicular; this gives credit to the surface states' behavior as two-dimensional transport.  
  Address  
  Corporate Author Thesis  
  Publisher Nature Publishing Group Place of Publication London Editor  
  Language Wos 000330044700008 Publication Date 2014-01-22  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2045-2322; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.259 Times cited 31 Open Access  
  Notes ERC grant Nu246791 – COUNTATOMS Approved Most recent IF: 4.259; 2014 IF: 5.578  
  Call Number UA @ lucian @ c:irua:114815 Serial 1436  
Permanent link to this record
 

 
Author Quintana, M.; López, A.M.; Rapino, S.; Toma, F.M.; Iurlo, M.; Carraro, M.; Sartorel, A.; Maccato, C.; Ke, X.; Bittencourt, C.; Da Ros, T.; Van Tendeloo, G.; Marcaccio, M.; Paolucci, F.; Prato, M.; Bonchio, M.; pdf  doi
openurl 
  Title Knitting the catalytic pattern of artificial photosynthesis to a hybrid graphene nanotexture Type A1 Journal article
  Year 2013 Publication ACS nano Abbreviated Journal Acs Nano  
  Volume 7 Issue 1 Pages 811-817  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract The artificial leaf project calls for new materials enabling multielectron catalysis with minimal overpotential, high turnover frequency, and long-term stability. Is graphene a better material than carbon nanotubes to enhance water oxidation catalysis for energy applications? Here we show that functionalized graphene with a tailored distribution of polycationic, quaternized, ammonium pendants provides an sp(2) carbon nanoplatform to anchor a totally inorganic tetraruthenate catalyst, mimicking the oxygen evolving center of natural PSII. The resulting hybrid material displays oxygen evolution at overpotential as low as 300 mV at neutral pH with negligible loss of performance after 4 h testing. This multilayer electroactive asset enhances the turnover frequency by 1 order of magnitude with respect to the isolated catalyst, and provides a definite up-grade of the carbon nanotube material, with a similar surface functionalization. Our innovation is based on a noninvasive, synthetic protocol for graphene functionalization that goes beyond the ill-defined oxidation-reduction methods, allowing a definite control of the surface properties.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000314082800088 Publication Date 2012-12-17  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 13.942 Times cited 69 Open Access  
  Notes 246791 COUNTATOMS; 262348 ESMI; ESF Cost Action NanoTP MP0901 Approved Most recent IF: 13.942; 2013 IF: 12.033  
  Call Number UA @ lucian @ c:irua:107707 Serial 1766  
Permanent link to this record
 

 
Author Quintana, M.; Ke, X.; Van Tendeloo, G.; Meneghetti, M.; Bittencourt, C.; Prato, M. pdf  doi
openurl 
  Title Light-induced selective deposition of Au nanoparticles on single-wall carbon nanotubes Type A1 Journal article
  Year 2010 Publication ACS nano Abbreviated Journal Acs Nano  
  Volume 4 Issue 10 Pages 6105-6113  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Novel applications of single-walled carbon nanotubes (SWNT) rely on the development of new strategies to make them easier to handle without affecting their structural properties. In this work, we have selectively deposited Au nanoparticles (Au NP) on SWNT assisted by UV light irradiation. XPS analysis and UV-vis spectroscopy indicate that the deposition occurs at the defects generated after oxidation of the SWNT. By addition of n-dodecylthiol, the separation of oxidized tubes with Au NP (Au-ox-SWNT) from tubes devoid of Au NP (bare tubes, b-SWNT) was achieved. Raman and UV-vis-NIR spectra indicate that UV irradiation induces a faster nucleation of Au NP on metallic SWNT. This new technique can be useful for the preparation of nanohybrid composites with enhanced properties, as increased thermal stability, and to obtain purified SWNT.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000283453700081 Publication Date 2010-09-24  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 13.942 Times cited 26 Open Access  
  Notes Approved Most recent IF: 13.942; 2010 IF: 9.865  
  Call Number UA @ lucian @ c:irua:99202 Serial 1819  
Permanent link to this record
 

 
Author Li, J.; Ji, M.; Schwarz, T.; Ke, X.; Van Tendeloo, G.; Yuan, J.; Pereira, P.J.; Huang, Y.; Zhang, G.; Feng, H.L.; Yuan, Y.H.; Hatano, T.; Kleiner, R.; Koelle, D.; Chibotaru, L.F.; Yamaura, K.; Wang, H.B.; Wu, P.H.; Takayama-Muromachi, E.; Vanacken, J.; Moshchalkov, V.V.; pdf  url
doi  openurl
  Title Local destruction of superconductivity by non-magnetic impurities in mesoscopic iron-based superconductors Type A1 Journal article
  Year 2015 Publication Nature communications Abbreviated Journal Nat Commun  
  Volume 6 Issue 6 Pages 7614  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract The determination of the pairing symmetry is one of the most crucial issues for the iron-based superconductors, for which various scenarios are discussed controversially. Non-magnetic impurity substitution is one of the most promising approaches to address the issue, because the pair-breaking mechanism from the non-magnetic impurities should be different for various models. Previous substitution experiments demonstrated that the non-magnetic zinc can suppress the superconductivity of various iron-based superconductors. Here we demonstrate the local destruction of superconductivity by non-magnetic zinc impurities in Ba0.5K0.5Fe2As2 by exploring phase-slip phenomena in a mesoscopic structure with 119 × 102 nm2 cross-section. The impurities suppress superconductivity in a three-dimensional Swiss cheese-like pattern with in-plane and out-of-plane characteristic lengths slightly below ~1.34 nm. This causes the superconducting order parameter to vary along abundant narrow channels with effective cross-section of a few square nanometres. The local destruction of superconductivity can be related to Cooper pair breaking by non-magnetic impurities.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000358857000007 Publication Date 2015-07-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2041-1723; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 12.124 Times cited 12 Open Access  
  Notes 246791 Countatoms Approved Most recent IF: 12.124; 2015 IF: 11.470  
  Call Number c:irua:126677 Serial 1827  
Permanent link to this record
 

 
Author Ke, X.; Bittencourt, C.; Bals, S.; Van Tendeloo, G. pdf  url
doi  openurl
  Title Low-dose patterning of platinum nanoclusters on carbon nanotubes by focused-electron-beam-induced deposition as studied by TEM Type A1 Journal article
  Year 2013 Publication Beilstein journal of nanotechnology Abbreviated Journal Beilstein J Nanotech  
  Volume 4 Issue Pages 77-86  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Focused-electron-beam-induced deposition (FEBID) is used as a direct-write approach to decorate ultrasmall Pt nanoclusters on carbon nanotubes at selected sites in a straightforward maskless manner. The as-deposited nanostructures are studied by transmission electron microscopy (TEM) in 2D and 3D, demonstrating that the Pt nanoclusters are well-dispersed, covering the selected areas of the CNT surface completely. The ability of FEBID to graft nanoclusters on multiple sides, through an electron-transparent target within one step, is unique as a physical deposition method. Using high-resolution TEM we have shown that the CNT structure can be well preserved thanks to the low dose used in FEBID. By tuning the electron-beam parameters, the density and distribution of the nanoclusters can be controlled. The purity of as-deposited nanoclusters can be improved by low-energy electron irradiation at room temperature.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000314499700001 Publication Date 2013-02-04  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2190-4286; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.127 Times cited 12 Open Access  
  Notes 262348 ESMI; 246791 COUNTATOMS; FWO G002410N; ESF Cost Action NanoTP MP0901 Approved Most recent IF: 3.127; 2013 IF: 2.332  
  Call Number UA @ lucian @ c:irua:106187 Serial 1848  
Permanent link to this record
 

 
Author Wang, J.T.W.; Cabana, L.; Bourgognon, M.; Kafa, H.; Protti, A.; Venner, K.; Shah, A.M.; Sosabowski, J.K.; Mather, S.J.; Roig, A.; Ke, X.; Van Tendeloo, G.; de Rosales, R.T.M.; Tobias, G.; Al-Jamal, K.T. pdf  doi
openurl 
  Title Magnetically decorated multiwalled carbon nanotubes as dual MRI and SPECT contrast agents Type A1 Journal article
  Year 2014 Publication Advanced functional materials Abbreviated Journal Adv Funct Mater  
  Volume 24 Issue 13 Pages 1880-1894  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Carbon nanotubes (CNTs) are one of the most promising nanomaterials to be used in biomedicine for drug/gene delivery as well as biomedical imaging. This study develops radio-labeled, iron oxide-decorated multiwalled CNTs (MWNTs) as dual magnetic resonance (MR) and single photon emission computed tomography (SPECT) contrast agents. Hybrids containing different amounts of iron oxide are synthesized by in situ generation. Physicochemical characterisations reveal the presence of superparamagnetic iron oxide nanoparticles (SPION) granted the magnetic properties of the hybrids. Further comprehensive examinations including high resolution transmission electron microscopy (HRTEM), fast Fourier transform simulations, X-ray diffraction, and X-ray photoelectron spectroscopy assure the conformation of prepared SPION as γ-Fe2O3. High r2 relaxivities are obtained in both phantom and in vivo MRI compared to the clinically approved SPION Endorem. The hybrids are successfully radio labeled with technetium-99m through a functionalized bisphosphonate and enable SPECT/CT imaging and γ-scintigraphy to quantitatively analyze the biodistribution in mice. No abnormality is found by histological examination and the presence of SPION and MWNT are identified by Perls stain and Neutral Red stain, respectively. TEM images of liver and spleen tissues show the co-localization of SPION and MWNTs within the same intracellular vesicles, indicating the in vivo stability of the hybrids after intravenous injection. The results demonstrate the capability of the present SPIONMWNT hybrids as dual MRI and SPECT contrast agents for in vivo use.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Weinheim Editor  
  Language Wos 000333674100007 Publication Date 2013-11-19  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1616-301X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 12.124 Times cited 50 Open Access  
  Notes Countatoms; Fp7; Esteem2; esteem2_ta Approved Most recent IF: 12.124; 2014 IF: 11.805  
  Call Number UA @ lucian @ c:irua:111589 Serial 1891  
Permanent link to this record
 

 
Author Chen, J.-J.; Ke, X.; Van Tendeloo, G.; Meng, J.; Zhou, Y.-B.; Liao, Z.-M.; Yu, D.-P. pdf  doi
openurl 
  Title Magnetotransport across the metal-graphene hybrid interface and its modulation by gate voltage Type A1 Journal article
  Year 2015 Publication Nanoscale Abbreviated Journal Nanoscale  
  Volume 7 Issue 7 Pages 5516-5524  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract The graphene-metal contact is very important for optimizing the performance of graphene based electronic devices. However, it is difficult to probe the properties of the graphene/metal interface directly via transport measurements in traditional graphene lateral devices, because the dominated transport channel is graphene, not the interface. Here, we employ the Au/graphene/Au vertical and lateral hybrid structure to unveil the metal-graphene interface properties, where the transport is dominated by the charge carriers across the interface. The magnetoresistance (MR) of Au/monolayer graphene/Au and Au/stacked two-layered graphene/Au devices is measured and modulated by gate voltage, demonstrating that the interface is a device. The gate-tunable MR is identified from the graphene lying on the SiO2 substrate and underneath the top metal electrode. Our unique structures couple the in-plane and out-of-plane transport and display linear MR with small amplitude oscillations at low temperatures. Under a magnetic field, the electronic coupling between the graphene edge states and the electrode leads to the appearance of quantum oscillations. Our results not only provide a new pathway to explore the intrinsic transport mechanism at the graphene/metal interface but also open up new vistas of magnetoelectronics.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Cambridge Editor  
  Language Wos 000351372400050 Publication Date 2015-02-19  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 7.367 Times cited 3 Open Access  
  Notes 246791 Countatoms Approved Most recent IF: 7.367; 2015 IF: 7.394  
  Call Number c:irua:125533 Serial 1931  
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Author Li, Y.J.; Wang, J.J.; Ye, J.C.; Ke, X.X.; Gou, G.Y.; Wei, Y.; Xue, F.; Wang, J.; Wang, C.S.; Peng, R.C.; Deng, X.L.; Yang, Y.; Ren, X.B.; Chen, L.Q.; Nan, C.W.; Zhang, J.X.; pdf  doi
openurl 
  Title Mechanical switching of nanoscale multiferroic phase boundaries Type A1 Journal article
  Year 2015 Publication Advanced functional materials Abbreviated Journal Adv Funct Mater  
  Volume 25 Issue 25 Pages 3405-3413  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Tuning the lattice degree of freedom in nanoscale functional crystals is critical to exploit the emerging functionalities such as piezoelectricity, shape-memory effect, or piezomagnetism, which are attributed to the intrinsic lattice-polar or lattice-spin coupling. Here it is reported that a mechanical probe can be a dynamic tool to switch the ferroic orders at the nanoscale multiferroic phase boundaries in BiFeO3 with a phase mixture, where the material can be reversibly transformed between the soft tetragonal-like and the hard rhombohedral-like structures. The microscopic origin of the nonvolatile mechanical switching of the multiferroic phase boundaries, coupled with a reversible 180 degrees rotation of the in-plane ferroelectric polarization, is the nanoscale pressure-induced elastic deformation and reconstruction of the spontaneous strain gradient across the multiferroic phase boundaries. The reversible control of the room-temperature multiple ferroic orders using a pure mechanical stimulus may bring us a new pathway to achieve the potential energy conversion and sensing applications.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Weinheim Editor  
  Language Wos 000355992600017 Publication Date 2015-04-20  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1616-301X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 12.124 Times cited 23 Open Access  
  Notes Approved Most recent IF: 12.124; 2015 IF: 11.805  
  Call Number c:irua:126430 Serial 1976  
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Author Zhang, J.; Ke, X.; Gou, G.; Seidel, J.; Xiang, B.; Yu, P.; Liang, W.I.; Minor, A.M.; Chu, Y.h.; Van Tendeloo, G.; Ren, X.; Ramesh, R.; pdf  doi
openurl 
  Title A nanoscale shape memory oxide Type A1 Journal article
  Year 2013 Publication Nature communications Abbreviated Journal Nat Commun  
  Volume 4 Issue Pages 2768-8  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Stimulus-responsive shape-memory materials have attracted tremendous research interests recently, with much effort focused on improving their mechanical actuation. Driven by the needs of nanoelectromechanical devices, materials with large mechanical strain, particularly at nanoscale level, are therefore desired. Here we report on the discovery of a large shape-memory effect in bismuth ferrite at the nanoscale. A maximum strain of up to ~14% and a large volumetric work density of ~600±90 J cm−3 can be achieved in association with a martensitic-like phase transformation. With a single step, control of the phase transformation by thermal activation or electric field has been reversibly achieved without the assistance of external recovery stress. Although aspects such as hysteresis, microcracking and so on have to be taken into consideration for real devices, the large shape-memory effect in this oxide surpasses most alloys and, therefore, demonstrates itself as an extraordinary material for potential use in state-of-art nanosystems.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000328023900006 Publication Date 2013-11-19  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2041-1723; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 12.124 Times cited 67 Open Access  
  Notes Countatoms Approved Most recent IF: 12.124; 2013 IF: 10.742  
  Call Number UA @ lucian @ c:irua:111431 Serial 2271  
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Author Yan, Y.; Zhou, X.; Jin, H.; Li, C.-Z.; Ke, X.; Van Tendeloo, G.; Liu, K.; Yu, D.; Dressel, M.; Liao, Z.-M. url  doi
openurl 
  Title Surface-Facet-Dependent Phonon Deformation Potential in Individual Strained Topological Insulator Bi2Se3 Nanoribbons Type A1 Journal article
  Year 2015 Publication ACS nano Abbreviated Journal Acs Nano  
  Volume 9 Issue 9 Pages 10244-10251  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Strain is an important method to tune the properties of topological insulators. For example, compressive strain can induce superconductivity in Bi2Se3 bulk material. Topological insulator nanostructures are the superior candidates to utilize the unique surface states due to the large surface to volume ratio. Therefore, it is highly desirable to monitor the local strain effects in individual topological insulator nanostructures. Here, we report the systematical micro-Raman spectra of single strained Bi2Se3 nanoribbons with different thicknesses and different surface facets, where four optical modes are resolved in both Stokes and anti-Stokes Raman spectral lines. A striking anisotropy of the strain dependence is observed in the phonon frequency of strained Bi2Se3 nanoribbons grown along the ⟨112̅0⟩ direction. The frequencies of the in-plane Eg2 and out-of-plane A1g1 modes exhibit a nearly linear blue-shift against bending strain when the nanoribbon is bent along the ⟨112̅0⟩ direction with the curved {0001} surface. In this case, the phonon deformation potential of the Eg2 phonon for 100 nm-thick Bi2Se3 nanoribbon is up to 0.94 cm–1/%, which is twice of that in Bi2Se3 bulk material (0.52 cm–1/%). Our results may be valuable for the strain modulation of individual topological insulator nanostructures.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Wos 000363915300079 Publication Date 2015-09-12  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 13.942 Times cited 14 Open Access  
  Notes Y.Y. would like to thank Xuewen Fu for helpful discussions. This work was supported by MOST (Nos. 2013CB934600, 2013CB932602) and NSFC (Nos. 11274014, 11234001). Approved Most recent IF: 13.942; 2015 IF: 12.881  
  Call Number c:irua:129216 Serial 3963  
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Author Ying, J.; Yang, X.-Y.; Hu, Z.-Y.; Mu, S.-C.; Janiak, C.; Geng, W.; Pan, M.; Ke, X.; Van Tendeloo, G.; Su, B.-L. pdf  doi
openurl 
  Title One particle@one cell : highly monodispersed PtPd bimetallic nanoparticles for enhanced oxygen reduction reaction Type A1 Journal article
  Year 2014 Publication Nano energy Abbreviated Journal Nano Energy  
  Volume 8 Issue Pages 214-222  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Highly monodispersed platinum-based nanoalloys are the best-known catalysts for the oxygen reduction reaction. Although certainly promising, the durability and stability are among the main requirements for commercializing fuel cell electrocatalysts in practical applications. Herein, we synthesize highly stable, durable and catalytic active monodispersed PtPd nano-particles encapsulated in a unique one particle@one cell structure by adjusting the viscosity of solvents using mesocellular foam. PtPd nanoparticles in mesocellular carbon foam exhibit an excellent electrocatalytic activity (over 4 times mass and specific activities than the commercial Pt/C catalyst). Most importantly, this nanocatalyst shows no obvious change of structure and only a 29.5% loss in electrochemically active surface area after 5000 potential sweeps between 0.6 and 1.1 V versus reversible hydrogen electrode cycles. (C) 2014 Elsevier Ltd. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000340981700026 Publication Date 2014-06-23  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2211-2855; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 12.343 Times cited 40 Open Access  
  Notes Approved Most recent IF: 12.343; 2014 IF: 10.325  
  Call Number UA @ lucian @ c:irua:119255 Serial 2465  
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Author Chen, J.J.; Wang, Q.; Meng, J.; Ke, X.; Van Tendeloo, G.; Bie, Y.Q.; Liu, J.; Liu, K.; Liao, Z.M.; Sun, D.; Yu, D.; pdf  url
doi  openurl
  Title Photovoltaic effect and evidence of carrier multiplication in graphene vertical homojunctions with asymmetrical metal contacts Type A1 Journal article
  Year 2015 Publication ACS nano Abbreviated Journal Acs Nano  
  Volume 9 Issue 9 Pages 8851-8858  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Graphene exhibits exciting potentials for high-speed wideband photodetection and high quantum efficiency solar energy harvest because of its broad spectral absorption, fast photoelectric response, and potential carrier multiplication. Although photocurrent can be generated near a metalgraphene interface in lateral devices, the photoactive area is usually limited to a tiny one-dimensional line-like interface region. Here, we report photoelectric devices based on vertical graphene two-dimensional homojunction, which is fabricated via vertically stacking four graphene monolayers with asymmetric metal contacts. The devices show excellent photovoltaic output with excitation wavelength ranging from visible light to mid-infrared. The wavelength dependence of the internal quantum efficiency gives direct evidence of the carrier multiplication effect in graphene. The simple fabrication process, easy scale-up, large photoresponsive active area, and broadband response of the vertical graphene device are very promising for practical applications in optoelectronics and photovoltaics.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000361935800023 Publication Date 2015-08-15  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 13.942 Times cited 11 Open Access  
  Notes 246791 Countatoms Approved Most recent IF: 13.942; 2015 IF: 12.881  
  Call Number c:irua:127689 Serial 2615  
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Author Ke, X.; Bittencourt, C.; Van Tendeloo, G. pdf  url
doi  openurl
  Title Possibilities and limitations of advanced transmission electron microscopy for carbon-based nanomaterials Type A1 Journal article
  Year 2015 Publication Beilstein journal of nanotechnology Abbreviated Journal Beilstein J Nanotech  
  Volume 6 Issue 6 Pages 1541-1557  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract A major revolution for electron microscopy in the past decade is the introduction of aberration correction, which enables one to increase both the spatial resolution and the energy resolution to the optical limit. Aberration correction has contributed significantly to the imaging at low operating voltages. This is crucial for carbon-based nanomaterials which are sensitive to electron irradiation. The research of carbon nanomaterials and nanohybrids, in particular the fundamental understanding of defects and interfaces, can now be carried out in unprecedented detail by aberration-corrected transmission electron microscopy (AC-TEM). This review discusses new possibilities and limits of AC-TEM at low voltage, including the structural imaging at atomic resolution, in three dimensions and spectroscopic investigation of chemistry and bonding. In situ TEM of carbon-based nanomaterials is discussed and illustrated through recent reports with particular emphasis on the underlying physics of interactions between electrons and carbon atoms.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000357977300001 Publication Date 2015-07-16  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2190-4286; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.127 Times cited 10 Open Access  
  Notes 246791 Countatoms Approved Most recent IF: 3.127; 2015 IF: 2.670  
  Call Number c:irua:126857 Serial 2682  
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Author Gengler, R.Y.N.; Toma, L.M.; Pardo, E.; Lloret, F.; Ke, X.; Van Tendeloo, G.; Gournis, D.; Rudolf, P. doi  openurl
  Title Prussian blue analogues of reduced dimensionality Type A1 Journal article
  Year 2012 Publication Small Abbreviated Journal Small  
  Volume 8 Issue 16 Pages 2532-2540  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Mixed-valence polycyanides (Prussian Blue analogues) possess a rich palette of properties spanning from room-temperature ferromagnetism to zero thermal expansion, which can be tuned by chemical modifications or the application of external stimuli (temperature, pressure, light irradiation). While molecule-based materials can combine physical and chemical properties associated with molecular-scale building blocks, their successful integration into real devices depends primarily on higher-order properties such as crystal size, shape, morphology, and organization. Herein a study of a new reduced-dimensionality system based on Prussian Blue analogues (PBAs) is presented. The system is built up by means of a modified Langmuir-Blodgett technique, where the PBA is synthesized from precursors in a self-limited reaction on a clay mineral surface. The focus of this work is understanding the magnetic properties of the PBAs in different periodic, low-dimensional arrangements, and the influence of the “on surface” synthesis on the final properties and dimensionality of the system.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Weinheim Editor  
  Language Wos 000307390300012 Publication Date 2012-07-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1613-6810; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 8.643 Times cited 17 Open Access  
  Notes Approved Most recent IF: 8.643; 2012 IF: 7.823  
  Call Number UA @ lucian @ c:irua:101104 Serial 2736  
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Author Hoek, M.; Coneri, F.; Poccia, N.; Renshaw Wang, X.; Ke, X.; Van Tendeloo, G.; Hilgenkamp, H. pdf  url
doi  openurl
  Title Strain accommodation through facet matching in La1.85Sr0.15CuO4/Nd1.85Ce0.15CuO4 ramp-edge junctions Type A1 Journal article
  Year 2015 Publication APL materials Abbreviated Journal Apl Mater  
  Volume 3 Issue 3 Pages 086101  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Scanning nano-focused X-ray diffraction and high-angle annular dark-field scanning transmission electron microscopy are used to investigate the crystal structure of ramp-edge junctions between superconducting electron-doped Nd1.85Ce0.15CuO4 and superconducting hole-doped La1.85Sr0.15CuO4 thin films, the latter being the top layer. On the ramp, a new growth mode of La1.85Sr0.15CuO4 with a 3.3° tilt of the c-axis is found. We explain the tilt by developing a strain accommodation model that relies on facet matching, dictated by the ramp angle, indicating that a coherent domain boundary is formed at the interface. The possible implications of this growth mode for the creation of artificial domains in morphotropic materials are discussed.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000360656800009 Publication Date 2015-08-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2166-532X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.335 Times cited 4 Open Access  
  Notes 312483 Esteem2; 246791 Countatoms; esteem2_jra2 Approved Most recent IF: 4.335; 2015 IF: NA  
  Call Number c:irua:127690 c:irua:127690 Serial 3163  
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Author Groeneveld, E.; Witteman, L.; Lefferts, M.; Ke, X.; Bals, S.; Van Tendeloo, G.; de Mello Donega, C. pdf  doi
openurl 
  Title Tailoring ZnSe-CdSe colloidal quantum dots via cation exchange : from core/shell to alloy nanocrystals Type A1 Journal article
  Year 2013 Publication ACS nano Abbreviated Journal Acs Nano  
  Volume 7 Issue 9 Pages 7913-7930  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract We report a study of Zn2+ by Cd2+ cation exchange (CE) in colloidal ZnSe nanocrystals (NCs). Our results reveal that CE in ZnSe NCs is a thermally activated isotropic process. The CE efficiency (i.e., fraction of Cd2+ ions originally in solution, Cdsol, that is incorporated in the ZnSe NC) increases with temperature and depends also on the Cdsol/ZnSe ratio. Interestingly, the reaction temperature can be used as a sensitive parameter to tailor both the composition and the elemental distribution profile of the product (Zn,Cd)Se NCs. At 150 °C ZnSe/CdSe core/shell hetero-NCs (HNCs) are obtained, while higher temperatures (200 and 220 °C) produce (Zn1xCdx)Se gradient alloy NCs, with increasingly smoother gradients as the temperature increases, until homogeneous alloy NCs are obtained at T ≥ 240 °C. Remarkably, sequential heating (150 °C followed by 220 °C) leads to ZnSe/CdSe core/shell HNCs with thicker shells, rather than (Zn1xCdx)Se gradient alloy NCs. Thermal treatment at 250 °C converts the ZnSe/CdSe core/shell HNCs into (Zn1xCdx)Se homogeneous alloy NCs, while preserving the NC shape. A mechanism for the cation exchange in ZnSe NCs is proposed, in which fast CE takes place at the NC surface, and is followed by relatively slower thermally activated solid-state cation diffusion, which is mediated by Frenkel defects. The findings presented here demonstrate that cation exchange in colloidal ZnSe NCs provides a very sensitive tool to tailor the nature and localization regime of the electron and hole wave functions and the optoelectronic properties of colloidal ZnSeCdSe NCs.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000330016900051 Publication Date 2013-08-13  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 13.942 Times cited 153 Open Access  
  Notes 262348 Esmi; 246791 Countatoms Approved Most recent IF: 13.942; 2013 IF: 12.033  
  Call Number UA @ lucian @ c:irua:110038 Serial 3469  
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Author Yan, Y.; Liao, Z.M.; Ke, X.; Van Tendeloo, G.; Wang, Q.; Sun, D.; Yao, W.; Zhou, S.; Zhang, L.; Wu, H.C.; Yu, D.P.; pdf  doi
openurl 
  Title Topological surface state enhanced photothermoelectric effect in Bi2Se3 nanoribbons Type A1 Journal article
  Year 2014 Publication Nano letters Abbreviated Journal Nano Lett  
  Volume 14 Issue 8 Pages 4389-4394  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract The photothermoelectric effect in topological insulator Bi2Se3 nanoribbons is studied. The topological surface states are excited to be spin-polarized by circularly polarized light. Because the direction of the electron spin is locked to its momentum for the spin-helical surface states, the photothermoelectric effect is significantly enhanced as the oriented motions of the polarized spins are accelerated by the temperature gradient. The results are explained based on the microscopic mechanisms of a photon induced spin transition from the surface Dirac cone to the bulk conduction band. The as-reported enhanced photothermoelectric effect is expected to have potential applications in a spin-polarized power source.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Washington Editor  
  Language Wos 000340446200028 Publication Date 2014-07-21  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1530-6984;1530-6992; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 12.712 Times cited 51 Open Access  
  Notes European Research Council under the Seventh Framework Program (FP7); ERC Advanced Grant No. 246791-COUNTATOMS. Approved Most recent IF: 12.712; 2014 IF: 13.592  
  Call Number UA @ lucian @ c:irua:118128 Serial 3678  
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Author Bittencourt, C.; Krüger, P.; Lagos, M.J.; Ke, X.; Van Tendeloo, G.; Ewels, C.; Umek, P.; Guttmann, P. pdf  url
doi  openurl
  Title Towards atomic resolution in sodium titanate nanotubes using near-edge X-ray-absorption fine-structure spectromicroscopy combined with multichannel multiple-scattering calculations Type A1 Journal article
  Year 2012 Publication Beilstein journal of nanotechnology Abbreviated Journal Beilstein J Nanotech  
  Volume 3 Issue Pages 789-797  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Recent advances in near-edge X-ray-absorption fine-structure spectroscopy coupled with transmission X-ray microscopy (NEXAFS-TXM) allow large-area mapping investigations of individual nano-objects with spectral resolution up to E/Delta E = 104 and spatial resolution approaching 10 nm. While the state-of-the-art spatial resolution of X-ray microscopy is limited by nanostructuring process constrains of the objective zone plate, we show here that it is possible to overcome this through close coupling with high-level theoretical modelling. Taking the example of isolated bundles of hydrothermally prepared sodium titanate nanotubes ((Na,H)TiNTs) we are able to unravel the complex nanoscale structure from the NEXAFS-TXM data using multichannel multiple-scattering calculations, to the extent of being able to associate specific spectral features in the O K-edge and Ti L-edge with oxygen atoms in distinct sites within the lattice. These can even be distinguished from the contribution of different hydroxyl groups to the electronic structure of the (Na,H)TiNTs.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000311482400001 Publication Date 2012-11-23  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2190-4286; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.127 Times cited 13 Open Access  
  Notes Approved Most recent IF: 3.127; 2012 IF: 2.374  
  Call Number UA @ lucian @ c:irua:105140 Serial 3684  
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Author Spyrou, K.; Potsi, G.; Diamanti, E.K.; Ke, X.; Serestatidou, E.; Verginadis, I.I.; Velalopoulou, A.P.; Evangelou, A.M.; Deligiannakis, Y.; Van Tendeloo, G.; Gournis, D.; Rudolf, P.; doi  openurl
  Title Towards Novel Multifunctional Pillared Nanostructures: Effective Intercalation of Adamantylamine in Graphene Oxide and Smectite Clays Type A1 Journal article
  Year 2014 Publication Advanced functional materials Abbreviated Journal Adv Funct Mater  
  Volume 24 Issue 37 Pages 5841-5850  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Multifunctional pillared materials are synthesized by the intercalation of cage-shaped adamantylamine (ADMA) molecules into the interlayer space of graphite oxide (GO) and aluminosilicate clays. The physicochemical and structural properties of these hybrids, determined by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman and X-ray photoemission (XPS) spectroscopies and transmission electron microscopy (TEM) show that they can serve as tunable hydrophobic/hydrophilic and stereospecific nanotemplates. Thus, in ADMA-pillared clay hybrids, the phyllomorphous clay provides a hydrophilic nanoenvironment where the local hydrophobicity is modulated by the presence of ADMA moieties. On the other hand, in the ADMA-GO hybrid, both the aromatic rings of GO sheets and the ADMA molecules define a hydrophobic nanoenvironment where sp(3)-oxo moieties (epoxy, hydroxyl and carboxyl groups), present on GO, modulate hydrophilicity. As test applications, these pillared nanostructures are capable of selective/stereospecific trapping of small chlorophenols or can act as cytotoxic agents.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Weinheim Editor  
  Language Wos 000342794500008 Publication Date 2014-07-19  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1616-301X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 12.124 Times cited 19 Open Access  
  Notes Approved Most recent IF: 12.124; 2014 IF: 11.805  
  Call Number UA @ lucian @ c:irua:121085 Serial 3686  
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Author Chemchuen, S.; Zhou, K.; Kabir, N.A.; Chen, Y.; Ke, X.; Van Tendeloo, G.; Verpoort, F. pdf  doi
openurl 
  Title Tuning metal sites of DABCO MOF for gas purification at ambient conditions Type A1 Journal article
  Year 2015 Publication Microporous and mesoporous materials: zeolites, clays, carbons and related materials Abbreviated Journal Micropor Mesopor Mat  
  Volume 201 Issue 201 Pages 277-285  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Metalorganic frameworks (MOFs) have emerged as new porous materials for capture and separation of binary gas mixtures. Tuning the metal sites in MOF structures has an impact on properties, which enhance affinity of gas adsorption and selectivity (e.g., surface area, cavity, electric field, etc.). The synthesis and characterization of a M-DABCO series (M = Ni, Co, Cu, Zn) of MOFs are described in this study. The experiments were conducted using multicomponent gas mixtures and the Ideal Adsorbed Solution Theory (IAST) was applied to determine the CO2/CH4 selectivity. Experimental adsorption isotherms were fitted with a model equation to evaluate the characteristic adsorption energy (Isosteric, Qst) of this series. The Ni metal in the M-DABCO series reveals the best performance concerning CO2 adsorption and CH4/CO2 selectivity at ambient conditions based on IAST calculations. The combination of characterizations, calculations and adsorption experiments were used to discuss the metal impact on the adsorption sites in the M-DABCO series at ambient conditions.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000345185200030 Publication Date 2014-09-20  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1387-1811; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.615 Times cited 38 Open Access  
  Notes 246791-Countatoms Approved Most recent IF: 3.615; 2015 IF: 3.453  
  Call Number c:irua:120473 Serial 3748  
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Author Skaltsas, T.; Ke, X.; Bittencourt, C.; Tagmatarchis, N. doi  openurl
  Title Ultrasonication induces oxygenated species and defects onto exfoliated graphene Type A1 Journal article
  Year 2013 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C  
  Volume 117 Issue 44 Pages 23272-23278  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract The effect of ultrasonication parameters, such as time and power applied, to exfoliate graphite in o-dichlorobenzene (o-DCB) and N-methyl-1,2-pyrrolidone (NMP) was examined. It was found that the concentration of graphene was higher in o-DCB, while its dispersibility was increased when sonication was applied for a longer period and/or at higher power. However, spectroscopic examination by X-ray photoelectron spectroscopy (XPS) revealed that ultrasonication causes defects and induces oxygen functional groups in the form of carboxylic acids and ethers/epoxides onto the graphene lattice. Additional proof for the latter arose from Raman, IR, and thermogravimetry studies. The carboxylic acids and ethers/epoxides onto exfoliated graphene were derived from air during ultrasonication and found independent of the solvent used for the exfoliation and the power and/or time ultrasonication applied. Quantitative evaluation of the amount of oxygenated species present on exfoliated graphene as performed by high-resolution XPS revealed that the relative oxygen percentage was higher when exfoliation was performed in NMP. Finally, the sonication time and/or power affected the oxygen content on exfoliated graphene, since extended ultrasonication resulted in a decrease in the oxygen content on exfoliated graphene, with a simultaneous increase of defected sp(3) carbon atoms.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Washington, D.C. Editor  
  Language Wos 000326845400090 Publication Date 2013-10-03  
  Series Editor Series Title Abbreviated Series Title  
  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 65 Open Access  
  Notes Approved Most recent IF: 4.536; 2013 IF: 4.835  
  Call Number UA @ lucian @ c:irua:112710 Serial 3797  
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Author Bittencourt, C.; Hitchock, A.P.; Ke, X.; Van Tendeloo, G.; Ewels, C.P.; Guttmann, P. pdf  url
doi  openurl
  Title X-ray absorption spectroscopy by full-field X-ray microscopy of a thin graphite flake: Imaging and electronic structure via the carbon K-edge Type A1 Journal article
  Year 2012 Publication Beilstein journal of nanotechnology Abbreviated Journal Beilstein J Nanotech  
  Volume 3 Issue Pages 345-350  
  Keywords (down) A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract We demonstrate that near-edge X-ray-absorption fine-structure spectra combined with full-field transmission X-ray microscopy can be used to study the electronic structure of graphite flakes consisting of a few graphene layers. The flake was produced by exfoliation using sodium cholate and then isolated by means of density-gradient ultracentrifugation. An image sequence around the carbon K-edge, analyzed by using reference spectra for the in-plane and out-of-plane regions of the sample, is used to map and spectrally characterize the flat and folded regions of the flake. Additional spectral features in both π and σ regions are observed, which may be related to the presence of topological defects. Doping by metal impurities that were present in the original exfoliated graphite is indicated by the presence of a pre-edge signal at 284.2 eV.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000303243400001 Publication Date 2012-04-25  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2190-4286; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.127 Times cited 15 Open Access  
  Notes Approved Most recent IF: 3.127; 2012 IF: 2.374  
  Call Number UA @ lucian @ c:irua:97703 Serial 3924  
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