|
|
“Atomic-scale modification of hybrid FePt cluster-assembled films”. Dobrynin AN, Ievlev DN, Verschoren G, Swerts J, van Bael MJ, Temst K, Lievens P, Piscopiello E, Van Tendeloo G, Zhou SQ, Vantomme A, Physical review : B : condensed matter and materials physics 73, 104421 (2006). http://doi.org/10.1103/PhysRevB.73.104421
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 13
DOI: 10.1103/PhysRevB.73.104421
|
|
|
|
“Observation of Co/CoO nanoparticles below the critical size for exchange bias”. Dobrynin AN, Temst K, Lievens P, Margueritat J, Gonzalo J, Afonso CN, Piscopiello E, Van Tendeloo G, Journal of applied physics 101, 113913 (2007). http://doi.org/10.1063/1.2736303
Abstract: We compare the magnetic properties of pure and oxidized Co nanoparticles embedded in an amorphous Al2O3 matrix. Nanoparticles with diameters of 2 or 3 nm were prepared by alternate pulsed laser deposition in high vacuum conditions, and some of them were exposed to O-2 after production and before being embedded. The nanoparticles are organized in layers, the effective edge-to-edge in-depth separation being 5 or 10 nm. The lower saturation magnetizations per Co atom for the samples containing oxidized nanoparticles provide evidence for the formation of antiferromagnetic CoO shells in the nanoparticles. None of the samples with Co/CoO nanoparticles show exchange bias, while vertical hysteresis loop shifts and enhanced coercivities (as compared to samples with pure Co nanoparticles) are observed. This constitutes evidence for the nanoparticles size being in all cases smaller than the critical size for exchange bias. The difference in coercivity versus temperature dependences for the samples with pure and oxidized Co nanoparticles shows that the exchange anisotropy in Co/CoO nanoparticles appears at temperatures lower than 50 K. (c) 2007 American Institute of Physics.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.068
Times cited: 27
DOI: 10.1063/1.2736303
|
|
|
|
“Diamond nucleation by carbon transport from buried nanodiamond TiO2 sol-gel composites”. Doenen M, Zhang L, Erni R, Williams OA, Hardy A, van Bael MK, Wagner P, Haenen K, Nesladek M, Van Tendeloo G, Advanced materials 21, 670 (2009). http://doi.org/10.1002/adma.200802305
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 19.791
Times cited: 20
DOI: 10.1002/adma.200802305
|
|
|
|
“The structural investigation of Ba4Bi3F17”. Dombrovski EN, Serov TV, Abakumov AM, Ardashnikova EI, Dolgikh VA, Van Tendeloo G, Journal of solid state chemistry 177, 312 (2004). http://doi.org/10.1016/j.jssc.2003.08.022
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 9
DOI: 10.1016/j.jssc.2003.08.022
|
|
|
|
“HREM characterization of substituted orthorhombic and monoclinic tubular phases”. Domengès B, Caldes MT, Hervieu M, Van Tendeloo G, Raveau B, Icem 13, 963 (1994)
Keywords: A3 Journal article; Electron microscopy for materials research (EMAT)
|
|
|
|
“Effects of nanocracks on the magnetic and electrical properties of La0.8Sr0.2MnO3 single crystals”. Dominiczak M, Ruyter A, Limelette P, Monot-Laffez I, Giovannelli F, Rossell MD, Van Tendeloo G, Solid state communications 149, 1543 (2009). http://doi.org/10.1016/j.ssc.2009.06.001
Abstract: An investigation of the physical properties of La0.8Sr0.2MnO3 single crystals grown by the molten zone technique is realized close to the metal-to-insulator transition temperature (TMI). In this paper, we review the effect of the structural defects through magnetotransport and local magnetic microstructures. From electron microscopy observations, some nanocrack defects (i.e. defects at a nanometer scale) were found, essentially in the center part of the single crystals. At room temperature, magnetic force microscopy measurements have shown that the absence of defects allowed a magnetic ordering of the domains at the crystal edge, which is the best-crystallized region. In addition, the magnetization loops have permitted us to verify that the crystal was ferromagnetically weaker in the center. On analyzing the electrical resistivity data, we observed in the linear current regime a sensitive variation of the resistivity due to defects, by comparing the center and the edge of the material at TMI. Additionally, at strong current, non-linearity phenomena have been supposed to be related to local heating. Finally, we discuss the structural disorder effect on the relaxation of the ferromagnetic domains.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.554
Times cited: 3
DOI: 10.1016/j.ssc.2009.06.001
|
|
|
|
“Relaxation phenomena at the metal-to-insulator transition in La0.8Sr0.2MnO3 single crystals”. Dominiczak M, Ruyter A, Limelette P, Monot-Laffez I, Giovannelli F, Rossell MD, Van Tendeloo G, Solid state communications 148, 340 (2008). http://doi.org/10.1016/j.ssc.2008.08.029
Abstract: The time dependence of the resistance RAC of a La0.8Sr0.2MnO3 single crystal has been investigated in the vicinity of the metal-to-insulator transition temperature. We used local probe microscopy to show the existence, at room temperature, of coexisting clusters of micrometer size. Our analysis shows that relaxation effects can be described with a simple exponential contribution using a random resistor-network, based on phase separation between insulating and metallic domains. Our results clearly prove the existence of a percolation threshold over which no percolation path exists. Moreover, these results highlight the significant role of the remanent magnetization.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.554
Times cited: 9
DOI: 10.1016/j.ssc.2008.08.029
|
|
|
|
“Preparation and structure analysis of Gd(OH)3 nanorods”. Du G, Van Tendeloo G, Nanotechnology 16, 595 (2005). http://doi.org/10.1088/0957-4484/16/4/043
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.44
Times cited: 28
DOI: 10.1088/0957-4484/16/4/043
|
|
|
|
“Formation of Mn304/C core-shell nanowires and a new MN-O phase by electron beam irradiation”. Du GH, Van Tendeloo G, Applied physics A : materials science &, processing 91, 393 (2008). http://doi.org/10.1007/s00339-008-4430-5
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.455
Times cited: 1
DOI: 10.1007/s00339-008-4430-5
|
|
|
|
“Cu(OH)2 nanowires, CuO nanowires and CuO nanobelts”. Du GH, Van Tendeloo G, Chemical physics letters 393, 64 (2004). http://doi.org/10.1016/j.cplett.2004.06.017
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.815
Times cited: 145
DOI: 10.1016/j.cplett.2004.06.017
|
|
|
|
“Flowerlike ZnO nanocones and nanowires: preparation, structure, and luminescence”. Du GH, Xu F, Yuan ZY, Van Tendeloo G, Applied physics letters 88, 243101 (2006). http://doi.org/10.1063/1.2211007
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 76
DOI: 10.1063/1.2211007
|
|
|
|
“Transmission electron microscopy and electron energy-loss spectroscopy analysis of manganese oxide nanowires”. Du GH, Yuan ZY, Van Tendeloo G, Applied physics letters 86 (2005). http://doi.org/10.1063/1.1861963
Abstract: Single-crystalline MnOOH and Mn3O4 nanowires have been prepared by hydrothermal treatment of commercial bulky manganese oxide particles. beta-MnO2 and alpha-Mn2O3 nanowires were prepared by calcination of MnOOH nanowires. Transmission electron microscopy analysis demonstrates that MnOOH nanowires grow directly from MnO2 raw particles. The diameter of the nanowires is 20-70 nm, while the length can reach several micrometers. MnOOH nanowires grow preferentially along the [010] direction and Mn3O4 nanowires prefer to grow along the [001] direction; the long dimension of both beta-MnO2 and alpha-Mn2O3 nanowires is along [001]. Electron energy-loss spectroscopy analysis shows that the position of the prepeak of the oxygen K edge shifts to higher energy and the energy separation between the two main peaks of the oxygen K edge decreases with decreasing manganese oxidation state. The manganese-white-line ratios (L-3/L-2) were calculated. (C) 2005 American Institute of Physics.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 46
DOI: 10.1063/1.1861963
|
|
|
|
“Direct visualization of irreducible ferrielectricity in crystals”. Du K, Guo L, Peng J, Chen X, Zhou Z-N, Zhang Y, Zheng T, Liang Y-P, Lu J-P, Ni Z-H, Wang S-S, Van Tendeloo G, Zhang Z, Dong S, Tian H, npj Quantum Materials 5, 49 (2020). http://doi.org/10.1038/S41535-020-00252-Y
Abstract: In solids, charge polarity can one-to-one correspond to spin polarity phenomenologically, e.g., ferroelectricity/ferromagnetism, antiferroelectricity/antiferromagnetism, and even dipole-vortex/magnetic-vortex, but ferrielectricity/ferrimagnetism kept telling a disparate story in microscopic level. Since the definition of a charge dipole involves more than one ion, there may be multiple choices for a dipole unit, which makes most ferrielectric orders equivalent to ferroelectric ones, i.e., this ferrielectricity is not necessary to be a real independent branch of polarity. In this work, by using the spherical aberration-corrected scanning transmission electron microscope, we visualize a nontrivial ferrielectric structural evolution in BaFe2Se3, in which the development of two polar sub-lattices is out-of-sync, for which we term it as irreducible ferrielectricity. Such irreducible ferrielectricity leads to a non-monotonic behavior for the temperature-dependent polarization, and even a compensation point in the ordered state. Our finding unambiguously distinguishes ferrielectrics from ferroelectrics in solids.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
DOI: 10.1038/S41535-020-00252-Y
|
|
|
|
“Manipulating topological transformations of polar structures through real-time observation of the dynamic polarization evolution”. Du K, Zhang M, Dai C, Zhou ZN, Xie YW, Ren ZH, Tian H, Chen LQ, Van Tendeloo G, Zhang Z, Nature communications 10, 4864 (2019). http://doi.org/10.1038/S41467-019-12864-5
Abstract: Topological structures based on controllable ferroelectric or ferromagnetic domain configurations offer the opportunity to develop microelectronic devices such as high-density memories. Despite the increasing experimental and theoretical insights into various domain structures (such as polar spirals, polar wave, polar vortex) over the past decade, manipulating the topological transformations of polar structures and comprehensively understanding its underlying mechanism remains lacking. By conducting an in-situ non-contact bias technique, here we systematically investigate the real-time topological transformations of polar structures in PbTiO3/SrTiO3 multilayers at an atomic level. The procedure of vortex pair splitting and the transformation from polar vortex to polar wave and out-of-plane polarization are observed step by step. Furthermore, the redistribution of charge in various topological structures has been demonstrated under an external bias. This provides new insights for the symbiosis of polar and charge and offers an opportunity for a new generation of microelectronic devices.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 12.124
DOI: 10.1038/S41467-019-12864-5
|
|
|
|
“Thin films and superlattices of multiferroic hexagonal rare earth manganites”. Dubourdieu C, Huot G, Gelard I, Roussel H, Lebedev OI, Van Tendeloo G, Philosophical magazine letters 87, 203 (2007). http://doi.org/10.1080/09500830601137173
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.941
Times cited: 17
DOI: 10.1080/09500830601137173
|
|
|
|
“Addition of yttrium into HfO2 films: microstructure and electrical properties”. Dubourdieu C, Rauwel E, Roussel H, Ducroquet F, Hollaender B, Rossell M, Van Tendeloo G, Lhostis S, Rushworth S, Journal of vacuum science and technology: A: vacuum surfaces and films 27, 503 (2009). http://doi.org/10.1116/1.3106627
Abstract: The cubic phase of HfO2 was stabilized by addition of yttrium in thin films grown on Si/SiO2 by metal-organic chemical vapor deposition. The cubic phase was obtained for contents of 6.5 at. % Y or higher at a temperature as low as 470 °C. The complete compositional range (from 1.5 to 99.5 at. % Y) was investigated. The crystalline structure of HfO2 was determined from x-ray diffraction, electron diffraction, and attenuated total-reflection infrared spectroscopy. For cubic films, the continuous increase in the lattice parameter indicates the formation of a solid-solution HfO2Y2O3. As shown by x-ray photoelectron spectroscopy, yttrium silicate is formed at the interface with silicon; the interfacial layer thickness increases with increasing yttrium content and increasing film thickness. The dependence of the intrinsic relative permittivity r as a function of Y content was determined. It exhibits a maximum of ~30 for ~8.8 at. % Y. The cubic phase is stable upon postdeposition high-temperature annealing at 900 °C under NH3.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.374
Times cited: 29
DOI: 10.1116/1.3106627
|
|
|
|
“Introduction to a special issue in honour of W. Owen Saxton, David J. Smith and Dirk Van Dyck on the occasion of their 65th birthdays”. Dunin-Borkowski RE, Lichte H, Tillmann K, Van Aert S, Van Tendeloo G, Ultramicroscopy 134, 1 (2013). http://doi.org/10.1016/j.ultramic.2013.07.013
Keywords: Editorial; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 1
DOI: 10.1016/j.ultramic.2013.07.013
|
|
|
|
“Atomic resolution mapping of phonon excitations in STEM-EELS experiments”. Egoavil R, Gauquelin N, Martinez GT, Van Aert S, Van Tendeloo G, Verbeeck J, Ultramicroscopy 147, 1 (2014). http://doi.org/10.1016/j.ultramic.2014.04.011
Abstract: Atomically resolved electron energy-loss spectroscopy experiments are commonplace in modern aberration-corrected transmission electron microscopes. Energy resolution has also been increasing steadily with the continuous improvement of electron monochromators. Electronic excitations however are known to be delocalized due to the long range interaction of the charged accelerated electrons with the electrons in a sample. This has made several scientists question the value of combined high spatial and energy resolution for mapping interband transitions and possibly phonon excitation in crystals. In this paper we demonstrate experimentally that atomic resolution information is indeed available at very low energy losses around 100 meV expressed as a modulation of the broadening of the zero loss peak. Careful data analysis allows us to get a glimpse of what are likely phonon excitations with both an energy loss and gain part. These experiments confirm recent theoretical predictions on the strong localization of phonon excitations as opposed to electronic excitations and show that a combination of atomic resolution and recent developments in increased energy resolution will offer great benefit for mapping phonon modes in real space.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 22
DOI: 10.1016/j.ultramic.2014.04.011
|
|
|
|
“Phase problem in the B-site ordering of La2CoMnO6 : impact on structure and magnetism”. Egoavil R, Huehn S, Jungbauer M, Gauquelin N, Béché, A, Van Tendeloo G, Verbeeck, Moshnyaga V, Nanoscale 7, 9835 (2015). http://doi.org/10.1039/c5nr01642h
Abstract: Epitaxial double perovskite La2CoMnO6 (LCMO) films were grown by metalorganic aerosol deposition on SrTiO3(111) substrates. A high Curie temperature, T-C = 226 K, and large magnetization close to saturation, M-S(5 K) = 5.8 mu(B)/f.u., indicate a 97% degree of B-site (Co,Mn) ordering within the film. The Co/Mn ordering was directly imaged at the atomic scale by scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy (STEM-EDX). Local electron-energy-loss spectroscopy (EELS) measurements reveal that the B-sites are predominantly occupied by Co2+ and Mn4+ ions in quantitative agreement with magnetic data. Relatively small values of the (1/2 1/2 1/2) superstructure peak intensity, obtained by X-ray diffraction (XRD), point out the existence of ordered domains with an arbitrary phase relationship across the domain boundary. The size of these domains is estimated to be in the range 35-170 nm according to TEM observations and modelling the magnetization data. These observations provide important information towards the complexity of the cation ordering phenomenon and its implications on magnetism in double perovskites, and similar materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 7.367
Times cited: 37
DOI: 10.1039/c5nr01642h
|
|
|
|
“Atomic scale investigation of a PbTiO3/SrRuO3/DyScO3 heterostructure”. Egoavil R, Tan H, Verbeeck J, Bals S, Smith B, Kuiper B, Rijnders G, Koster G, Van Tendeloo G, Applied physics letters 102, 223106 (2013). http://doi.org/10.1063/1.4809597
Abstract: An epitaxial PbTiO3 thin film grown on self-organized crystalline SrRuO3 nanowires deposited on a DyScO3 substrate with ordered DyO and ScO2 chemical terminations is investigated by transmission electron microscopy. In this PbTiO3/SrRuO3/DyScO3 heterostructure, the SrRuO3 nanowires are assumed to grow on only one type of substrate termination. Here, we report on the structure, morphology, and chemical composition analysis of this heterostructure. Electron energy loss spectroscopy reveals the exact termination sequence in this complex structure. The energy loss near-edge structure of the Ti-L-2,L-3, Sc-L-2,L-3, and O K edges shows intrinsic interfacial electronic reconstruction. Furthermore, PbTiO3 domain walls are observed to start at the end of the nanowires resulting in atomic steps on the film surface. (C) 2013 AIP Publishing LLC.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 12
DOI: 10.1063/1.4809597
|
|
|
|
“Evaluation of mesoporous carbon aerogels as carriers of the non-steroidal anti-inflammatory drug ibuprofen”. Eleftheriadis GK, Filippousi M, Tsachouridou V, Darda M-A, Sygellou L, Kontopoulou I, Bouropoulos N, Steriotis T, Charalambopoulou G, Vizirianakis IS, Van Tendeloo G, Fatouros DG, International journal of pharmaceutics 515, 262 (2016). http://doi.org/10.1016/J.IJPHARM.2016.10.008
Abstract: Towards the development of novel drug carriers for oral delivery of poorly soluble drugs mesoporous aerogel carbons (CAs), namely CA10 and CA20 with different pore sizes (10 and 20 nm, respectively), were evaluated. The non-steroidal anti-inflammatory lipophilic compound ibuprofen was incorporated via passive loading. The drug loaded carbon aerogels were systemically investigated by means of High-Resolution Transmission Electron Microscopy (HR-TEM), Nitrogen physisorption studies, X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC), X-ray photon electron spectroscopy (XPS) and zeta-potential studies. In vitro release studies were performed in simulated intestinal fluids reflecting both fasted (FaSSIF) and fed (FeSSIF) state conditions. Cytotoxicity studies were conducted with human intestinal cells (Caco-2). Drug was in an amorphous state in the pores of the carbon carrier as shown from the physicochemical characterization studies. The results showed marked differences in the release profiles for ibuprofen from the two aerogels in the media tested whereas in vitro toxicity profiles appear to be compatible with potential therapeutic applications at low concentrations. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Pharmacology. Therapy; Electron microscopy for materials research (EMAT)
Impact Factor: 3.649
Times cited: 7
DOI: 10.1016/J.IJPHARM.2016.10.008
|
|
|
|
“Order and twining in Sb2W0.75Mo0.25O6”. Enjalbert R, Galy J, Castro A, Lidin S, Withers R, Van Tendeloo G, Solid state sciences 5, 721 (2003). http://doi.org/10.1016/S1293-2558(03)00093-1
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.811
Times cited: 3
DOI: 10.1016/S1293-2558(03)00093-1
|
|
|
|
“P-type ZnO thin films grown by RF plasma beam assisted Pulsed Laser Deposition”. Epurescu G, Dinescu G, Moldovan A, Birjega R, Dipietrantonio F, Verona E, Verardi P, Nistor LC, Ghica C, Van Tendeloo G, Dinescu A, Superlattices and microstructures 42, 79 (2007). http://doi.org/10.1016/j.spmi.2007.04.072
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.123
Times cited: 19
DOI: 10.1016/j.spmi.2007.04.072
|
|
|
|
“BaHfO3artificial pinning centres in TFA-MOD-derived YBCO and GdBCO thin films”. Erbe M, Hänisch J, Hühne R, Freudenberg T, Kirchner A, Molina-Luna L, Damm C, Van Tendeloo G, Kaskel S, Schultz L, Holzapfel B, Superconductor science and technology 28, 114002 (2015). http://doi.org/10.1088/0953-2048/28/11/114002
Abstract: Chemical solution deposition (CSD) is a promising way to realize REBa2Cu3O7−x (REBCO;RE = rare earth (here Y, Gd))-coated conductors with high performance in applied magnetic fields. However, the preparation process contains numerous parameters which need to be tuned to achieve high-quality films. Therefore, we investigated the growth of REBCO thin films containing nanometre-scale BaHfO3 (BHO) particles as pinning centres for magnetic flux lines, with emphasis on the influence of crystallization temperature and substrate on the microstructure and superconductivity. Conductivity, microscopy and x-ray investigations show an enhanced performance of BHO nano-composites in comparison to pristine REBCO. Further, those measurements reveal the superiority of GdBCO to YBCO—e.g. by inductive critical current densities, Jc, at self-field and 77 K. YBCO is outperformed by more than 1 MA cm−2 with Jc values of up to 5.0 MA cm−2 for 265 nm thick layers of GdBCO(BHO) on lanthanum aluminate. Transport in-field Jc measurements demonstrate high pinning force maxima of around 4 GN m−3 for YBCO(BHO) and GdBCO(BHO). However, the irreversibility fields are appreciably higher for GdBCO. The critical temperature was not significantly reduced upon BHO addition to both YBCO and GdBCO, indicating a low tendency for Hf diffusion into the REBCO matrix. Angular-dependent Jc measurements show a reduction of the anisotropy in the same order of magnitude for both REBCO compounds. Theoretical models suggest that more than one sort of pinning centre is active in all CSD films.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.878
Times cited: 36
DOI: 10.1088/0953-2048/28/11/114002
|
|
|
|
Erni R, Abakumov AM, Rossell MD, Batuk D, Tsirlin AA, Né,nert G, Van Tendeloo G (2014) Nanoscale phase separation in perovskites revisited. London, 216–217
Keywords: L1 Letter to the editor; Electron microscopy for materials research (EMAT)
Impact Factor: 39.737
Times cited: 5
DOI: 10.1038/nmat3865
|
|
|
|
“ZnO@ZIF-8 : stabilization of quantum confined ZnO nanoparticles by a zinc methylimidazolate framework and their surface structural characterization probed by CO2 adsorption”. Esken D, Noei H, Wang Y, Wiktor C, Turner S, Van Tendeloo G, Fischer RA, Journal of materials chemistry 21, 5907 (2011). http://doi.org/10.1039/c1jm10091b
Abstract: The microporous and activated zeolitic imidazolate framework (Zn(MeIM)2; MeIM = imidazolate-2-methyl; ZIF-8) was loaded with the MOCVD precursor diethyl zinc [Zn(C2H5)2]. Exposure of ZIF-8 to the vapour of the volatile organometallic molecule resulted in the formation of the inclusion compound [Zn(C2H5)2]0.38@ZIF-8 revealing two precursor molecules per cavity. In a second step the obtained material was treated with oxygen (5 vol% in argon) at various temperatures (oxidative annealing) to achieve the composite material ZnO0.35@ZIF-8. The new material was characterized with powder XRD, FT-IR, UV-vis, solid state NMR, elemental analysis, N2 sorption measurements, and transmission electron microscopy. The data give evidence for the presence of nano-sized ZnO particles stabilized by ZIF-8 showing a blue-shift of the UV-vis absorption caused by quantum size effect (QSE). The surface structure and reactivity of embedded ZnO nanoparticles were characterized via carbon dioxide adsorption at different temperatures monitored by ultra-high vacuum FTIR techniques. It was found that the surface of ZnO nanoparticles is dominated by polar OZnO and ZnZnO facets as well as by defect sites, which all exhibit high reactivity towards CO2 activation forming various adsorbed carbonate and chemisorbed CO2δ− species.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 76
DOI: 10.1039/c1jm10091b
|
|
|
|
“Au@ZIFs: stabilization and encapsulation of cavity-size matching gold clusters inside functionalized Zeolite Imidazolate Frameworks, ZIFs”. Esken D, Turner S, Lebedev OI, Van Tendeloo G, Fischer RA, Chemistry of materials 22, 6393 (2010). http://doi.org/10.1021/cm102529c
Abstract: The selective formation and stabilization of very small, naked metal particles inside the cavities of metal organic frameworks (MOFs) and the simultaneous realization of an even distribution of the particles throughout the crystalline MOF host matrix over a wide range of metal loading are challenging goals. MOFs reveal high specific surface areas, tunable pore sizes, and organic linkers, which are able to interact with guests. The chemically very robust zeolite imidazolate frameworks (ZIFs) are a subclass of MOFs. We chose the microporous sodalite-like ZIF-8 (Zn(MelM)(2); IM = imidazolate) and ZIF-90 (Zn(ICA)(2); ICA = imidazolate-2-carboxyaldehyde) as host matrices to influence the dispersion of imbedded gold nanoparticles (Au NPs). The metal loading was achieved via gas phase infiltration of [Au(CO)Cl] followed by a thermal hydrogenation step to form the Au NPs. Low-dose high-resolution transmission electron microscopy ((HR)TEM) and electron tomography reveal a homogeneous distribution of Au NPs throughout the ZIF matrix. The functional groups of ZIF-90 direct the anchoring of intermediate Au species and stabilize drastically smaller and quite monodisperse Au NPs in contrast to the parent not functionalized ZIF-8. The particles can be very small, match the cavity size and approach defined molecular clusters of magic numbers, i.e., Au(55), independently from the level of loading. Post-synthetic oxidation of the aldehyde groups to yield alkyl esters by the adjacent, catalytically active metal NPs is presented as a new concept of encapsulating nanoparticles inside MOFs and allows multiple steps of metal loadings without decomposition of the MOF.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 194
DOI: 10.1021/cm102529c
|
|
|
|
“GaN@ZIF-8 : selective formation of gallium nitride quantum dots inside a zinc methylimidazolate framework”. Esken D, Turner S, Wiktor C, Kalidindi SB, Van Tendeloo G, Fischer RA, Journal of the American Chemical Society 133, 16370 (2011). http://doi.org/10.1021/ja207077u
Abstract: The microporous zeolitic imidazolate framework [Zn(MeIM)2; ZIF-8; MeIM = imidazolate-2-methyl] was quantitatively loaded with trimethylamine gallane [(CH3)3NGaH3]. The obtained inclusion compound [(CH3)3NGaH3]@ZIF-8 reveals three precursor molecules per host cavity. Treatment with ammonia selectively yields the caged cyclotrigallazane intermediate (H2GaNH2)3@ZIF-8, and further annealing gives GaN@ZIF-8. This new composite material was characterized with FT-IR spectroscopy, solid-state NMR spectroscopy, powder X-ray diffraction, elemental analysis, (scanning) transmission electron microscopy combined with electron energy-loss spectroscopy, photoluminescence (PL) spectroscopy, and N2 sorption measurements. The data give evidence for the presence of GaN nanoparticles (13 nm) embedded in the cavities of ZIF-8, including a blue-shift of the PL emission band caused by the quantum size effect.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 82
DOI: 10.1021/ja207077u
|
|
|
|
“Metal-decorated multi-wall carbon nanotubes for low temperature gas sensing”. Espinosa EH, Lonescu R, Bittencourt C, Felten A, Erni R, Van Tendeloo G, Pireaux J-J, Llobet E, Thin solid films : an international journal on the science and technology of thin and thick films 515, 8322 (2007). http://doi.org/10.1016/j.tsf.2007.03.017
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.879
Times cited: 86
DOI: 10.1016/j.tsf.2007.03.017
|
|
|
|
“Conversion of platelets into dislocation loops and voidite formation in type IaB diamonds”. Evans T, Kiflawi I, Luyten W, Van Tendeloo G, Woods GS, Proceedings of the Royal Society of London: series A: mathematical and physical sciences 449, 295 (1995). http://doi.org/10.1098/rspa.1995.0045
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.192
Times cited: 32
DOI: 10.1098/rspa.1995.0045
|
|
