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“Nanocrystal Core Size and Shape Substitutional Doping and Underlying Crystalline Order in Nanocrystal Superlattices”. Jishkariani D, Elbert KC, Wu Y, Lee JD, Hermes M, Wang D, van Blaaderen A, Murray CB, ACS nano 13, 5712 (2019). http://doi.org/10.1021/ACSNANO.9B01107
Abstract: Substitutional doping is a potentially powerful technique to control the properties of nanocrystal (NC) superlattices (SLs). However, not every NC can be substituted into any lattice, as the NCs have to be close in size and shape, limiting the application of substitutional doping. Here we show that this limitation can be overcome by employing ligands of various size. We show that small NCs with long ligands can be substituted into SLs of big NCs with short ligands. Furthermore, we show that shape differences can also be overcome and that cubes can substitute spheres when both are coated with long ligands. Finally, we use the NC effective ligand size, softness, and effective overall size ratio to explain observed doping behaviors.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 13.942
Times cited: 6
DOI: 10.1021/ACSNANO.9B01107
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“Tailoring Cu+ for Ga3+ cation exchange in Cu2-xS and CuInS2 nanocrystals by controlling the Ga precursor chemistry”. Hinterding SOM, Berends AC, Kurttepeli M, Moret M-E, Meeldijk JD, Bals S, van der Stam W, de Donega CM, ACS nano 13, 12880 (2019). http://doi.org/10.1021/ACSNANO.9B05337
Abstract: Nanoscale cation exchange (CE) has resulted in colloidal nanomaterials that are unattainable by direct synthesis methods. Aliovalent CE is complex and synthetically challenging because the exchange of an unequal number of host and guest cations is required to maintain charge balance. An approach to control aliovalent CE reactions is the use of a single reactant to both supply the guest cation and extract the host cation. Here, we study the application of GaCl3-L complexes [L = trioctylphosphine (TOP), triphenylphosphite (TPP), diphenylphosphine (DPP)] as reactants in the exchange of Cu+ for Ga3+ in Cu2-xS nanocrystals. We find that noncomplexed GaCl3 etches the nanocrystals by S2- extraction, whereas GaCl3-TOP is unreactive. Successful exchange of Cu+ for Ga3+ is only possible when GaCl3 is complexed with either TPP or DPP. This is attributed to the pivotal role of the Cu2-xS-GaCl3-L activated complex that forms at the surface of the nanocrystal at the onset of the CE reaction, which must be such that simultaneous Ga3+ insertion and Cu+ extraction can occur. This requisite is only met if GaCl3 is bound to a phosphine ligand, with a moderate bond strength, to allow facile dissociation of the complex at the nanocrystal surface. The general validity of this mechanism is demonstrated by using GaCl3-DPP to convert CuInS2 into (Cu,Ga,In)S-2 nanocrystals, which increases the photoluminescence quantum yield 10 -fold, while blue -shifting the photoluminescence into the NIR biological window. This highlights the general applicability of the mechanistic insights provided by our work.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 13.942
Times cited: 27
DOI: 10.1021/ACSNANO.9B05337
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“Understanding and Controlling the Crystallization Process in Reconfigurable Plasmonic Superlattices”. Bagiński M, Pedrazo-Tardajos A, Altantzis T, Tupikowska M, Vetter A, Tomczyk E, Suryadharma RNS, Pawlak M, Andruszkiewicz A, Górecka E, Pociecha D, Rockstuhl C, Bals S, Lewandowski W, Acs Nano , acsnano.0c09746 (2021). http://doi.org/10.1021/acsnano.0c09746
Abstract: The crystallization of nanomaterials is a primary source of solid-state, photonic structures. Thus, a detailed understanding of this process is of paramount importance for the successful application of photonic nanomaterials in emerging optoelectronic technologies. While colloidal crystallization has been thoroughly studied, for example, with advanced in situ electron microscopy methods, the noncolloidal crystallization (freezing) of nanoparticles (NPs) remains so far unexplored. To fill this gap, in this work, we present proof-of principle experiments decoding a crystallization of reconfigurable assemblies of NPs at a solid state. The chosen material corresponds to an excellent testing bed, as it enables both in situ and ex situ investigation using X-ray diffraction (XRD), transmission electron microscopy (TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), atomic force microscopy (AFM), and optical spectroscopy in visible and ultraviolet range (UV−vis) techniques. In particular, ensemble measurements with small-angle XRD highlighted the dependence of the correlation length in the NPs assemblies on the number of heating/cooling cycles and the rate of cooling. Ex situ TEM imaging further supported these results by revealing a dependence of domain size and structure on the sample preparation route and by showing we can control the domain size over 2 orders of magnitude. The application of HAADF-STEM tomography, combined with in situ thermal control, provided three-dimensional single-particle level information on the positional order evolution within assemblies. This combination of real and reciprocal space provides insightful information on the anisotropic, reversibly reconfigurable assemblies of NPs. TEM measurements also highlighted the importance of interfaces in the polydomain structure of nanoparticle solids, allowing us to understand experimentally observed differences in UV−vis extinction spectra of the differently prepared crystallites. Overall, the obtained results show that the combination of in situ heating HAADF-STEM tomography with XRD and ex situ TEM techniques is a powerful approach to study nanoparticle freezing processes and to reveal the crucial impact of disorder in the solid-state aggregates of NPs on their plasmonic properties.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 13.942
Times cited: 10
DOI: 10.1021/acsnano.0c09746
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“State of the art and prospects for Halide Perovskite Nanocrystals”. Dey A, Ye J, De A, Debroye E, Ha SK, Bladt E, Kshirsagar AS, Wang Z, Yin J, Wang Y, Quan LN, Yan F, Gao M, Li X, Shamsi J, Debnath T, Cao M, Scheel MA, Kumar S, Steele JA, Gerhard M, Chouhan L, Xu K, Wu X-gang, Li Y, Zhang Y, Dutta A, Han C, Vincon I, Rogach AL, Nag A, Samanta A, Korgel BA, Shih C-J, Gamelin DR, Son DH, Zeng H, Zhong H, Sun H, Demir HV, Scheblykin IG, Mora-Sero I, Stolarczyk JK, Zhang JZ, Feldmann J, Hofkens J, Luther JM, Perez-Prieto J, Li L, Manna L, Bodnarchuk M I, Kovalenko M V, Roeffaers MBJ, Pradhan N, Mohammed OF, Bakr OM, Yang P, Muller-Buschbaum P, Kamat P V, Bao Q, Zhang Q, Krahne R, Galian RE, Stranks SD, Bals S, Biju V, Tisdale WA, Yan Y, Hoye RLZ, Polavarapu L, Acs Nano 15, 10775 (2021). http://doi.org/10.1021/ACSNANO.0C08903
Abstract: Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of perovskite nanocrystals and understanding of their properties and applications. In this comprehensive review, researchers having expertise in different fields (chemistry, physics, and device engineering) of metal-halide perovskite nanocrystals have joined together to provide a state of the art overview and future prospects of metal-halide perovskite nanocrystal research.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 13.942
Times cited: 538
DOI: 10.1021/ACSNANO.0C08903
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“Cyan emission in two-dimensional colloidal Cs2CdCl4:SB3+ Ruddlesden-Popper phase nanoplatelets”. Locardi F, Samoli M, Martinelli A, Erdem O, Vale Magalhaes D, Bals S, Hens Z, Acs Nano 15, 17729 (2021). http://doi.org/10.1021/ACSNANO.1C05684
Abstract: Metal halide perovskites are one of the most investigated materials in optoelectronics, with their lead-based counterparts being renowned for their enhanced optoelectronic performance. The 3D CsPbX3 structure has set the standard with many studies currently attempting to substitute lead with other metals while retaining the properties of this material. This effort has led to the fabrication of metal halides with lower dimensionality, wherein particular 2D layered perovskite structures have captured attention as inspiration for the next generation of colloidal semiconductors. Here we report the synthesis of the Ruddlesden-Popper Cs2CdCl4:Sb3+ phase as colloidal nanoplatelets (NPs) using a facile hot injection approach under atmospheric conditions. Through strict adjustment of the synthesis parameters with emphasis on the ligand ratio, we obtained NPs with a relatively uniform size and good morphological control. The particles were characterized through transmission electron microscopy, synchrotron X-ray diffraction, and pair distribution function analysis. The spectroscopic characterization revealed most strikingly an intense cyan emission under UV excitation with a measured PLQY of similar to 20%. The emission was attributed to the Sb3+-doping within the structure.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 13.942
Times cited: 34
DOI: 10.1021/ACSNANO.1C05684
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“Acoustically driven stark effect in transition metal dichalcogenide monolayers”. Scolfaro D, Finamor M, Trinchao LO, Rosa BLT, Chaves A, Santos P V, Iikawa F, Couto ODD Jr, Acs Nano 15, 15371 (2021). http://doi.org/10.1021/ACSNANO.1C06854
Abstract: The Stark effect is one of the most efficient mechanisms to manipulate many-body states in nanostructured systems. In mono- and few-layer transition metal dichalcogenides, it has been successfully induced by optical and electric field means. Here, we tune the optical emission energies and dissociate excitonic states in MoSe2 monolayers employing the 220 MHz in-plane piezoelectric field carried by surface acoustic waves. We transfer the monolayers to high dielectric constant piezoelectric substrates, where the neutral exciton binding energy is reduced, allowing us to efficiently quench (above 90%) and red-shift the excitonic optical emissions. A model for the acoustically induced Stark effect yields neutral exciton and trion in-plane polarizabilities of 530 and 630 x 10(-5) meV/(kV/cm)(2), respectively, which are considerably larger than those reported for monolayers encapsulated in hexagonal boron nitride. Large in-plane polarizabilities are an attractive ingredient to manipulate and modulate multiexciton interactions in two-dimensional semiconductor nanostructures for optoelectronic applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 13.942
DOI: 10.1021/ACSNANO.1C06854
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“An oxysulfate Fe2O(SO4)2 electrode for sustainable Li-based batteries”. Sun M, Rousse G, Abakumov AM, Van Tendeloo G, Sougrati M-T, Courty M, Doublet M-L, Tarascon J-M, Journal of the American Chemical Society 136, 12658 (2014). http://doi.org/10.1021/ja505268y
Abstract: High-performing Fe-based electrodes for Li-based batteries are eagerly pursued because of the abundance and environmental benignity of iron, with especially great interest in polyanionic compounds because of their flexibility in tuning the Fe3+/Fe2+ redox potential. We report herein the synthesis and structure of a new Fe-based oxysulfate phase, Fe2O(SO4)(2), made at low temperature from abundant elements, which electrochemically reacts with nearly 1.6 Li atoms at an average voltage of 3.0 V versus Li+/Li, leading to a sustained reversible capacity of similar to 125 mAh/g. The Li insertiondeinsertion process, the first ever reported in any oxysulfate, entails complex phase transformations associated with the position of iron within the FeO6 octahedra. This finding opens a new path worth exploring in the quest for new positive electrode materials.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 11
DOI: 10.1021/ja505268y
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“Artificial construction of the layered Ruddlesden-Popper manganite La2Sr2Mn3O10 by reflection high energy electron diffraction monitored pulsed laser deposition”. Palgrave RG, Borisov P, Dyer MS, McMitchell SRC, Darling GR, Claridge JB, Batuk M, Tan H, Tian H, Verbeeck J, Hadermann J, Rosseinsky MJ;, Journal of the American Chemical Society 134, 7700 (2012). http://doi.org/10.1021/ja211138x
Abstract: Pulsed laser deposition has been used to artificially construct the n = 3 Ruddlesden Popper structure La2Sr2Mn3O10 in epitaxial thin film form by sequentially layering La1-xSrxMnO3 and SrO unit cells aided by in situ reflection high energy electron diffraction monitoring. The interval deposition technique was used to promote two-dimensional SrO growth. X-ray diffraction and cross-sectional transmission electron microscopy indicated that the trilayer structure had been formed. A site ordering was found to differ from that expected thermodynamically, with the smaller Sr2+ predominantly on the R site due to kinetic trapping of the deposited cation sequence. A dependence of the out-of-plane lattice parameter on growth pressure was interpreted as changing the oxygen content of the films. Magnetic and transport measurements on fully oxygenated films indicated a frustrated magnetic ground state characterized as a spin glass-like magnetic phase with the glass temperature T-g approximate to 34 K. The magnetic frustration has a clear in-plane (ab) magnetic anisotropy, which is maintained up to temperatures of 150 K. Density functional theory calculations suggest competing antiferromagnetic and ferromagnetic long-range orders, which are proposed as the origin of the low-temperature glassy state.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 27
DOI: 10.1021/ja211138x
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“Control of surface plasmon localization via self-assembly of silver nanoparticles along silver nanowires”. Tran ML, Centeno SP, Hutchison JA, Engelkamp H, Liang D, Van Tendeloo G, Sels BF, Hofkens J, Uji-i H, Journal of the American Chemical Society 130, 17240 (2008). http://doi.org/10.1021/ja807218e
Abstract: A simple and low-cost method to create metal−metal hybrid nanostructures possessing fairly regularly spaced hot-spots of surface plasmon resonances is proposed. The nanohybrid structure was prepared via self-assembly during a simple drop-casting procedure, using chemically synthesized silver nanowires and silver nanoparticles prepared in a single batch of a polyol process. Wide field illumination of these nanohybrids produced hot-spots with spacings of around 500 nm to 1 ìm. The intensity of the emission/scattering from the hot-spots fluctuates over time. The proposed structure can be useful for the development of molecular-sensors or as a substrate for surface enhanced Raman/fluorescence spectroscopy.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 51
DOI: 10.1021/ja807218e
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“Facile synthesis of Ba1-xKxFe2As2 superconductors via hydride route”. Zaikina JV, Batuk M, Abakumov AM, Navrotsky A, Kauziarich SM, Journal of the American Chemical Society 136, 16932 (2014). http://doi.org/10.1021/ja509907r
Abstract: We have developed a fast, easy, and scalable synthesis method for Ba1xKxFe2As2 (0 ≤ x ≤ 1) superconductors using hydrides BaH2 and KH as a source of barium and potassium metals. Synthesis from hydrides provides better mixing and easier handling of the starting materials, consequently leading to faster reactions and/or lower synthesis temperatures. The reducing atmosphere provided by the evolved hydrogen facilitates preparation of oxygen-free powders. By a combination of methods we have shown that Ba1xKxFe2As2 obtained via hydride route has the same characteristics as when it is prepared by traditional solid-state synthesis. Refinement from synchrotron powder X-ray diffraction data confirms a linear dependence of unit cell parameters upon K content as well as the tetragonal to orthorhombic transition at low temperatures for compositions with x < 0.2. Magnetic measurements revealed dome-like dependence of superconducting transition temperature Tc upon K content with a maximum of 38 K for x close to 0.4. Electron diffraction and high-resolution high-angle annular dark-field scanning transmission electron microscopy indicates an absence of Ba/K ordering, while local inhomogeneity in the Ba/K distribution takes place at a scale of several angstroms along [110] crystallographic direction.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 13
DOI: 10.1021/ja509907r
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“Fluorinated heterometallic \beta-diketonates as volatile single-source precursors for the synthesis of low-valent mixed-metal fluorides”. Navulla A, Tsirlin AA, Abakumov AM, Shpanchenko RV, Zhang H, Dikarev EV, Journal of the American Chemical Society 133, 692 (2011). http://doi.org/10.1021/ja109128r
Abstract: Hexafluoroacetylacetonates that contain lead and divalent first-row transition metals, PbM(hfac)4 (M = Ni (1), Co (2), Mn (3), Fe (4), and Zn (5)), have been synthesized. Their heterometallic structures are held together by strong Lewis acid−base interactions between metal atoms and diketonate ligands acting in chelating−bridging fashion. Compounds 1−5 are highly volatile and decompose below 350 °C. Fluorinated heterometallic β-diketonates have been used for the first time as volatile single-source precursors for the preparation of mixed-metal fluorides. Complex fluorides of composition Pb2MF6 have been obtained by decomposition of 1−5 in a two-zone furnace under low-pressure nitrogen flow. Lead−transition metal fluorides conform to orthorhombically distorted Aurivillius-type structure with layers of corner-sharing [MF6] octahedra separated by α-PbO-type (Pb2F2) blocks. Pb2NiF6 and Pb2CoF6 were found to exhibit magnetic ordering below 80 and 43 K, respectively. The ordering is antiferromagnetic, with a weak, uncompensated moment due to the canting of spins. The Pb2MF6 fluorides represent a new class of prospective magnetoelectric materials combining transition metals and lone-pair main-group cations.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 28
DOI: 10.1021/ja109128r
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“Mn(I) in an extended oxide : the synthesis and characterization of La1-xCaxMnO2+\delta (0.6\leq x\leq1)”. Dixon E, Hadermann J, Ramos S, Goodwin AL, Hayward MA, Journal of the American Chemical Society 133, 18397 (2011). http://doi.org/10.1021/ja207616c
Abstract: Reduction of La1xCaxMnO3 (0.6 ≤ x ≤ 1) perovskite phases with sodium hydride yields materials of composition La1xCaxMnO2+δ. The calcium-rich phases (x = 0.9, 1) adopt (La0.9Ca0.1)0.5Mn0.5O disordered rocksalt structures. However local structure analysis using reverse Monte Carlo refinement of models against pair distribution functions obtained from neutron total scattering data reveals lanthanum-rich La1xCaxMnO2+δ (x = 0.6, 0.67, 0.7) phases adopt disordered structures consisting of an intergrowth of sheets of MnO6 octahedra and sheets of MnO4 tetrahedra. X-ray absorption data confirm the presence of Mn(I) centers in La1xCaxMnO2+δ phases with x < 1. Low-temperature neutron diffraction data reveal La1xCaxMnO2+δ (x = 0.6, 0.67, 0.7) phases become antiferromagnetically ordered at low temperature.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 33
DOI: 10.1021/ja207616c
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“A polar corundum oxide displaying weak ferromagnetism at room temperature”. Li MR, Adem U, McMitchell SRC, Xu Z, Thomas CI, Warren JE, Giap DV, Niu H, Wan X, Palgrave RG, Schiffmann F, Cora F, Slater B, Burnett TL, Cain MG, Abakumov AM, Van Tendeloo G, Thomas MF, Rosseinsky MJ, Claridge JB;, Journal of the American Chemical Society 134, 3737 (2012). http://doi.org/10.1021/ja208395z
Abstract: Combining long-range magnetic order with polarity in the same structure is a prerequisite for the design of (magnetoelectric) multiferroic materials. There are now several demonstrated strategies to achieve this goal, but retaining magnetic order above room temperature remains a difficult target. Iron oxides in the +3 oxidation state have high magnetic ordering temperatures due to the size of the coupled moments. Here we prepare and characterize ScFeO3 (SFO), which under pressure and in strain-stabilized thin films adopts a polar variant of the corundum structure, one of the archetypal binary oxide structures. Polar corundum ScFeO3 has a weak ferromagnetic ground state below 356 K-this is in contrast to the purely antiferromagnetic ground state adopted by the well-studied ferroelectric BiFeO3.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 48
DOI: 10.1021/ja208395z
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“Preparation, structure, and electrochemistry of layered polyanionic hydroxysulfates : LiMSO4OH (M = Fe, Co, Mn) electrodes for Li-Ion batteries”. Subban CV, Ati M, Rousse G, Abakumov AM, Van Tendeloo G, Janot R, Tarascon J-M, Journal of the American Chemical Society 135, 3653 (2013). http://doi.org/10.1021/ja3125492
Abstract: The Li-ion rechargeable battery, due to its high energy density, has driven remarkable advances in portable electronics. Moving toward more sustainable electrodes could make this technology even more attractive to large-volume applications. We present here a new family of 3d-metal hydroxysulfates of general formula LiMSO4OH (M = Fe, Co, and Mn) among which (i) LiFeSO4OH reversibly releases 0.7 Li+ at an average potential of 3.6 V vs Li+/Li-0, slightly higher than the potential of currently lauded LiFePO4 (3.45 V) electrode material, and (ii) LiCoSO4OH shows a redox activity at 4.7 V vs Li+/Li-0. Besides, these compounds can be easily made at temperatures near 200 degrees C via a synthesis process that enlists a new intermediate phase of composition M-3(SO4)(2)(OH)(2) (M = Fe, Co, Mn, and Ni), related to the mineral caminite. Structurally, we found that LiFeSO4OH is a layered phase unlike the previously reported 3.2 V tavorite LiFeSO4OH. This work should provide an impetus to experimentalists for designing better electrolytes to fully tap the capacity of high-voltage Co-based hydroxysulfates, and to theorists for providing a means to predict the electrochemical redox activity of two polymorphs.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 53
DOI: 10.1021/ja3125492
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“Ruthenium nanoparticles inside porous (Zn40(bdC)(3)) by hydrogenolysis of adsorbed (Ru(cod)(cot)): a solid-state reference system for surfactant-stabilized ruthenium colloids”. Schröder F, Esken D, Cokoja M, van den Berg MWE, Lebedev OI, Van Tendeloo G, Walaszek B, Buntkowsky G, Limbach HH, Chaudret B, Fischer RA;, Journal of the American Chemical Society 130, 6119 (2008). http://doi.org/10.1021/ja078231u
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 272
DOI: 10.1021/ja078231u
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“A simple road for the transformation of few-layer graphene into MWNTs”. Quintana M, Grzelczak M, Spyrou K, Calvaresi M, Bals S, Kooi B, Van Tendeloo G, Rudolf P, Zerbetto F, Prato M, Journal of the American Chemical Society 134, 13310 (2012). http://doi.org/10.1021/ja303131j
Abstract: We report the direct formation of multiwalled carbon nanotubes (MWNT) by ultrasonication of graphite in dimethylformamide (DMF) upon addition of ferrocene aldehyde (Fc-CHO). The tubular structures appear exclusively at the edges of graphene layers and contain Fe clusters. Pc in conjunction with benzyl aldehyde, or other Fc derivatives, does not induce formation of NT. Higher amounts of Fc-CHO added to the dispersion do not increase significantly MWNT formation. Increasing the temperature reduces the amount of formation of MWNTs and shows the key role of ultrasound-induced cavitation energy. It is concluded that Fc-CHO first reduces the concentration of radical reactive species that slice graphene into small moieties, localizes itself at the edges of graphene, templates the rolling up of a sheet to form a nanoscroll, where it remains trapped, and finally accepts and donates unpaired electron to the graphene edges and converts the less stable scroll into a MWNT. This new methodology matches the long held notion that CNTs are rolled up graphene layers. The proposed mechanism is general and will lead to control the production of carbon nanostructures by simple ultrasonication treatments.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 56
DOI: 10.1021/ja303131j
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“TEM and laser-polarized 129Xe NMR characterization of oxidatively purified carbon nanotubes”. Kneller JM, Soto RJ, Surber SE, Colomer JF, Fonseca A, Nagy JB, Van Tendeloo G, Pietrass T, Journal of the American Chemical Society 122, 10591 (2000). http://doi.org/10.1021/ja994441y
Abstract: Multiwall carbon nanotubes are produced by decomposition of acetylene at 600 degreesC on metal catalysts supported on NaY zeolite. The support and the metal are eliminated by dissolving them in aqueous hydrofluoric acid (HF). Two methods were used to eliminate the pyrolitic carbon: oxidation in air at 500 degreesC and oxidation by potassium permanganate in acidic solution at 70 degreesC. The progress and efficacy of the purification methods are verified by TEM. The properties of the purified multiwalled carbon nanotubes are probed using C-13 and Xe-129 NMR spectroscopy under continuous-flow optical-pumping conditions. Xenon is shown to penetrate the interior of the nanotubes. A distribution of inner tube diameters gives rise to chemical shift dispersion. When the temperature is lowered, an increasing fraction of xenon resides inside the nanotubes and is not capable of exchanging with xenon in the interparticle space. In the case of the permanganate-oxidized sample, rapid xenon relaxation is attributed to interaction with residual MnO2 nanoparticles in the interior of the tubes.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 53
DOI: 10.1021/ja994441y
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“Topotactic reduction as a route to new close-packed anion deficient perovskites: structure and magnetism of 4H-BaMnO2+x”. Hadermann J, Abakumov AM, Adkin JJ, Hayward MA, Journal of the American Chemical Society 131, 10598 (2009). http://doi.org/10.1021/ja903216d
Abstract: The anion-deficient perovskite 4H-BaMnO2+x has been obtained by a topotactic reduction, with LiH, of the hexagonal perovskite 4H-BaMnO3−x. The crystal structure of 4H-BaMnO2+x was solved using electron diffraction and X-ray powder diffraction and further refined using neutron powder diffraction (S.G. Pnma, a = 10.375(2) Å, b = 9.466(2) Å, c = 11.276(3) Å, at 373 K). The orthorhombic superstructure arises from the ordering of oxygen vacancies within a 4H (chch) stacking of close packed c-type BaO2.5 and h-type BaO1.5 layers. The ordering of the oxygen vacancies transforms the Mn2O9 units of face-sharing MnO6 octahedra into Mn2O7 (two corner-sharing tetrahedra) and Mn2O6 (two edge-sharing tetrahedra) groups. The Mn2O7 and Mn2O6 groups are linked by corner-sharing into a three-dimensional framework. The structures of the BaO2.5 and BaO1.5 layers are different from those observed previously in anion-deficient perovskites providing a new type of order pattern of oxygen atoms and vacancies in close packed structures. Magnetization measurements and neutron diffraction data reveal 4H-BaMnO2+x adopts an antiferromagnetically ordered state below TN ≈ 350 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 25
DOI: 10.1021/ja903216d
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“Understanding and promoting the rapid preparation of the triplite-phase of LiFeSO4F for use as a large-potential Fe cathode”. Ati M, Sathiya M, Boulineau S, Reynaud M, Abakumov A, Rousse G, Melot B, Van Tendeloo G, Tarascon J-M, Journal of the American Chemical Society 134, 18380 (2012). http://doi.org/10.1021/ja3074402
Abstract: The development of new electrode materials, which are composed of Earth-abundant elements and that can be made via eco-efficient processes, is becoming absolutely necessary for reasons of sustainable production. The 3.9 V triplite-phase of LiFeSO4F, compared to the 3.6 V tavorite-phase, could satisfy this requirement provided the currently complex synthetic pathway can be simplified. Here, we present our work aiming at better understanding the reaction mechanism that govern its formation as a way to optimize its preparation. We first demonstrate, using complementary X-ray diffraction and transmission electron microscopy studies, that triplite-LiFeSO4F can nucleate from tavorite-LiFeSO4F via a reconstructive process whose kinetics are significantly influenced by moisture and particle morphology. Perhaps the most spectacular finding is that it is possible to prepare electrochemically active triplite-LiFeSO4F from anhydrous precursors using either reactive spark plasma sintering (SPS) synthesis in a mere 20 min at 320 degrees C or room temperature ball milling for 3 h. These new pathways appear to be strongly driven by the easy formation of a disordered phase with higher entropy, as both techniques trigger disorder via rapid annealing steps or defect creation. Although a huge number of phases adopts the tavorite structure-type, this new finding offers both a potential way to prepare new compositions in the triplite structure and a wealth of opportunities for the synthesis of new materials which could benefit many domains beyond energy storage.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 36
DOI: 10.1021/ja3074402
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“Understanding the roles of anionic redox and oxygen release during electrochemical cycling of lithium-rich layered Li4FeSbO6”. McCalla E, Sougrati MT, Rousse G, Berg EJ, Abakumov A, Recham N, Ramesha K, Sathiya M, Dominko R, Van Tendeloo G, Novák P, Tarascon JM;, Journal of the American Chemical Society 137, 4804 (2015). http://doi.org/10.1021/jacs.5b01424
Abstract: Li-rich oxides continue to be of immense interest as potential next generation Li-ion battery positive electrodes, and yet the role of oxygen during cycling is still poorly understood. Here, the complex electrochemical behavior of Li4FeSbO6 materials is studied thoroughly with a variety of methods. Herein, we show that oxygen release occurs at a distinct voltage plateau from the peroxo/superoxo formation making this material ideal for revealing new aspects of oxygen redox processes in Li-rich oxides. Moreover, we directly demonstrate the limited reversibility of the oxygenated species (O-2(n-); n = 1, 2, 3) for the first time. We also find that during charge to 4.2 V iron is oxidized from +3 to an unusual +4 state with the concomitant formation of oxygenated species. Upon further charge to 5.0 V, an oxygen release process associated with the reduction of iron +4 to +3 is present, indicative of the reductive coupling mechanism between oxygen and metals previously reported. Thus, in full state of charge, lithium removal is fully compensated by oxygen only, as the iron and antimony are both very close to their pristine states. Besides, this charging step results in complex phase transformations that are ultimately destructive to the crystallinity of the material. Such findings again demonstrate the vital importance of fully understanding the behavior of oxygen in such systems. The consequences of these new aspects of the electrochemical behavior of lithium-rich oxides are discussed in detail.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 86
DOI: 10.1021/jacs.5b01424
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“Supracrystalline Colloidal Eggs: Epitaxial Growth and Freestanding Three-Dimensional Supracrystals in Nanoscaled Colloidosomes”. Yang Z, Altantzis T, Zanaga D, Bals S, Van Tendeloo G, Pileni M-P, Journal of the American Chemical Society 138, 3493 (2016). http://doi.org/10.1021/jacs.5b13235
Abstract: The concept of template-confined chemical reactions allows the synthesis of complex molecules that would hardly be producible through conventional method. This idea was developed to produce high quality nanocrystals more than 20 years ago. However, template-mediated assembly of colloidal nanocrystals is still at an elementary level, not only because of the limited templates suitable for colloidal assemblies, but also because of the poor control over the assembly of nanocrystals within a confined space. Here, we report the design of a new system called “supracrystalline colloidal eggs” formed by controlled assembly of nanocrystals into complex colloidal supracrystals through superlattice-matched epitaxial overgrowth along the existing colloidosomes. Then, with this concept, we extend the supracrystalline growth to lattice-mismatched binary nanocrystal superlattices, in order to reach anisotropic superlattice growths, yielding freestanding binary nanocrystal supracrystals that could not be produced previously.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 57
DOI: 10.1021/jacs.5b13235
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“Topochemical nitridation with anion vacancy -assisted N3-/O2- exchange”. Mikita R, Aharen T, Yamamoto T, Takeiri F, Ya T, Yoshimune W, Fujita K, Yoshida S, Tanaka K, Batuk D, Abakumov AM, Brown CM, Kobayashi Y, Kageyama H;, Journal of the American Chemical Society 138, 3211 (2016). http://doi.org/10.1021/jacs.6b00088
Abstract: We present how the introduction of anion vacancies in oxyhydrides enables a route to access new oxynitrides, by conducting ammonolysis of perovskite oxyhydride EuTiO3-xHx (x similar to 0.18). At 400 degrees C, similar to our studies on BaTiO3-xHx, hydride lability enables a low temperature direct ammonolysis of EUTi3.82+O-2.82/H-0.18, leading to the N3-/H--exchanged product EuTi4+O2.82No0.12 square 0.06 center dot When the ammonolysis temperature was increased up to 800 degrees C, we observed a further nitridation involving N3-/O2- exchange, yielding a fully oxidized Eu3+Ti4+O2N with the GdFeO3-type distortion (Pnma) as a metastable phase, instead of pyrochlore structure. Interestingly, the same reactions using the oxide EuTiO3 proceeded through a 1:1 exchange of N3- with O-2 only above 600 degrees C and resulted in incomplete nitridation to EuTi02.25N0.75, indicating that anion vacancies created during the initial nitridation process of EuTiO2.82H0.18 play a crucial role in promoting anion (N3-/O2-) exchange at high temperatures. Hence, by using (hydride-induced) anion-deficient precursors, we should be able to expand the accessible anion composition of perovskite oxynitrides.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 28
DOI: 10.1021/jacs.6b00088
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“Galvanic Replacement Coupled to Seeded Growth as a Route for Shape-Controlled Synthesis of Plasmonic Nanorattles”. Polavarapu L, Zanaga D, Altantzis T, Rodal-Cedeira S, Pastoriza-Santos I, Pérez-Juste J, Bals S, Liz-Marzán LM, Journal of the American Chemical Society 138, 11453 (2016). http://doi.org/10.1021/jacs.6b06706
Abstract: Shape-controlled synthesis of metal nanoparticles (NPs) requires mechanistic understanding toward the development of modern nanoscience and nanotechnology. We demonstrate here an unconventional shape transformation of Au@Ag core−shell NPs (nanorods and nanocubes) into octahedral nanorattles via roomtemperature galvanic replacement coupled with seeded growth. The corresponding morphological and chemical transformations were investigated in three dimensions, using state-of-the-art X-ray energy-dispersive spectroscopy (XEDS) tomography. The addition of a reducing agent (ascorbic acid) plays a key role in this unconventional mechanistic path, in which galvanic replacement is found to dominate initially when the shell is made of Ag, while seeded growth suppresses transmetalation when a composition of Au:Ag (∼60:40) is reached in the shell, as revealed by quantitative XEDS tomography. This work not only opens new avenues toward the shape control of hollow NPs beyond the morphology of sacrificial templates, but also expands our understanding of chemical transformations in nanoscale galvanic replacement reactions. The XEDS electron tomography study presented here can be generally applied to investigate a wide range of nanoscale morphological and chemical transformations.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 75
DOI: 10.1021/jacs.6b06706
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“High-Yield Seeded Growth of Monodisperse Pentatwinned Gold Nanoparticles through Thermally Induced Seed Twinning”. Sánchez-Iglesias A, Winckelmans N, Altantzis T, Bals S, Grzelczak M, Liz-Marzán LM, Journal of the American Chemical Society 139, 107 (2016). http://doi.org/10.1021/jacs.6b12143
Abstract: We show here that thermal treatment of small seeds results in extensive twinning and a subsequent drastic yield improvement (>85%) in the formation of pentatwinned nanoparticles, with pre-selected morphology (nanorods, bipyramids and decahedra) and aspect ratio. The “quality” of the seeds thus defines the yield of the obtained nanoparticles, which in the case of nanorods avoids the need for additives such as Ag+ ions. This modified seeded growth method also improves reproducibility, as the seeds can be stored for extended periods of time without compromising the quality of the final nanoparticles. Additionally, minor modification of the seeds with Pd allows their localization within the final particles, which opens new avenues toward mechanistic studies. All together, these results represent a paradigm shift in anisotropic gold nanoparticle synthesis.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 267
DOI: 10.1021/jacs.6b12143
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“ZnTaO2N: Stabilized High-Temperature LiNbO3-type Structure”. Kuno Y, Tassel C, Fujita K, Batuk D, Abakumov AM, Shitara K, Kuwabara A, Moriwake H, Watabe D, Ritter C, Brown CM, Yamamoto T, Takeiri F, Abe R, Kobayashi Y, Tanaka K, Kageyama H, Journal of the American Chemical Society 138, 15950 (2016). http://doi.org/10.1021/JACS.6B08635
Abstract: By using a high-pressure reaction, we prepared a new oxynitride ZnTaO2N that crystallizes in a centrosymmetric (R (3) over barc) high-temperature LiNbO3-type structure (HTLN-type). The stabilization of the HTLN-type structure down to low temperatures (at least 20 K) makes it possible to investigate not only the stability of this phase, but also the phase transition to a noncentrosymmetric (R3c) LiNbO3-type structure (LN-type) which is yet to be clarified. Synchrotron and neutron diffraction studies in combination with transmission electron microscopy show that Zn is located at a disordered 12c site instead of 6a, implying an order disorder mechanism of the phase transition. It is found that the dosed d-shell of Zn2+, as well as the high-valent Ta5+ ion, is responsible for the stabilization of the HTLN-type structure, affording a novel quasitriangular ZnO2N coordination. Interestingly, only 3% Zn substitution for MnTaO2N induces a phase transition from LN- to HTLN-type structure, implying the proximity in energy between the two structural types, which is supported by the first-principles calculations.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 13
DOI: 10.1021/JACS.6B08635
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“1D-2D-3D Transformation Synthesis of Hierarchical Metal-Organic Framework Adsorbent for Multicomponent Alkane Separation”. Wee LH, Meledina M, Turner S, Van Tendeloo G, Zhang K, Marleny Rodriguez-Albelo L, Masala A, Bordiga S, Jiang J, Navarro JAR, Kirschhock CEA, Martens JA, Journal of the American Chemical Society 139, 819 (2017). http://doi.org/10.1021/JACS.6B10768
Abstract: A new hierarchical MOF consisting of Cu(II) centers connected by benzene-tricarboxylates (BTC) is prepared by thermoinduced solid transformation of a dense CuBTC precursor phase. The mechanism of the material formation has been thoroughly elucidated and revealed a transformation of a ribbon-like 1D building unit into 2D layers and finally a 3D network. The new phase contains excess copper, charge compensated by systematic hydroxyl groups, which leads to an open microporous framework with tunable permanent mesoporosity. The new phase is particularly attractive for molecular separation. Energy consumption of adsorptive separation processes can be lowered by using adsorbents that discriminate molecules based on adsorption entropy rather than enthalpy differences. In separation of a 11-component mixture of C-1-C-6 alkanes, the hierarchical phase outperforms the structurally related microporous HKUST-1 as well as silicate-based hierarchical materials. Grand canonical Monte Carlo (GCMC) simulation provides microscopic insight into the structural host-guest interaction, confirming low adsorption enthalpies and significant entropic contributions to the molecular separation. The unique three-dimensional hierarchical structure as well as the systematic presence of Cu(II) unsaturated coordination sites cause this exceptional behavior.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 33
DOI: 10.1021/JACS.6B10768
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“Room Temperature Magnetically Ordered Polar Corundum GaFeO3 Displaying Magnetoelectric Coupling”. Niu H, Pitcher MJ, Corkett AJ, Ling S, Mandal P, Zanella M, Dawson K, Stamenov P, Batuk D, Abakumov AM, Bull CL, Smith RI, Murray CA, Day SJ, Slater B, Cora F, Claridge JB, Rosseinsky MJ, Journal of the American Chemical Society 139, 1520 (2017). http://doi.org/10.1021/jacs.6b11128
Abstract: The polar corundum structure type offers a route to new room temperature multiferroic materials, as the partial LiNbO3-type cation ordering that breaks inversion symmetry may be combined with long-range magnetic ordering of high spin d(5) cations above room temperature in the AFeO(3) system. We report the synthesis of a polar corundum GaFeO3 by a high-pressure, high-temperature route and demonstrate that its polarity arises from partial LiNbO3 -type cation ordering by complementary use of neutron, X-ray, and electron diffraction methods. In situ neutron diffraction shows that the polar corundum forms directly from AlFeO3-type GaFeO3 under the synthesis conditions. The A(3+)/Fe3+ cations are shown to be more ordered in polar corundum GaFeO3 than in isostructural ScFeO3. This is explained by DFT calculations which indicate that the extent of ordering is dependent on the configurational entropy available to each system at the very different synthesis temperatures required to form their corundum structures. Polar corundum GaFeO3 exhibits weak ferromagnetism at room temperature that arises from its Fe2O3-like magnetic ordering, which persists to a temperature of 408 K. We demonstrate that the polarity and magnetization are coupled in this system with a measured linear magnetoelectric coupling coefficient of 0.057 ps/m. Such coupling is a prerequisite for potential applications of polar corundum materials in multiferroic/magnetoelectric devices.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 12
DOI: 10.1021/jacs.6b11128
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“Halide perovskite-lead chalcohalide nanocrystal heterostructures”. Imran M, Peng L, Pianetti A, Pinchetti V, Ramade J, Zito J, Di Stasio F, Buha J, Toso S, Song J, Infante I, Bals S, Brovelli S, Manna L, Journal Of The American Chemical Society 143, 1435 (2021). http://doi.org/10.1021/JACS.0C10916
Abstract: We report the synthesis of colloidal CsPbX3-Pb4S3Br2 (X = Cl, Br, I) nanocrystal heterostructures, providing an example of a sharp and atomically resolved epitaxial interface between a metal halide perovskite and a non-perovskite lattice. The CsPbBr3-Pb4S3Br2 nanocrystals are prepared by a two-step direct synthesis using preformed subnanometer CsPbBr3 clusters. Density functional theory calculations indicate the creation of a quasi-type II alignment at the heterointerface as well as the formation of localized trap states, promoting ultrafast separation of photogenerated excitons and carrier trapping, as confirmed by spectroscopic experiments. Postsynthesis reaction with either Cl- or I- ions delivers the corresponding CsPbCI3-Pb4S3Br2 and CsPbI3-Pb4S3Br2 heterostructures, thus enabling anion exchange only in the perovskite domain. An increased structural rigidity is conferred to the perovskite lattice when it is interfaced with the chalcohalide lattice. This is attested by the improved stability of the metastable gamma phase (or “black” phase) of CsPbI3 in the CsPbI3-Pb4S3Br2 heterostructure.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 54
DOI: 10.1021/JACS.0C10916
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“Topochemical deintercalation of Li from layered LiNiB : toward 2D MBene”. Bhaskar G, Gvozdetskyi V, Batuk M, Wiaderek KM, Sun Y, Wang R, Zhang C, Carnahan SL, Wu X, Ribeiro RA, Bud'ko SL, Canfield PC, Huang W, Rossini AJ, Wang C-Z, Ho K-M, Hadermann J, Zaikina J V, Journal Of The American Chemical Society 143, 4213 (2021). http://doi.org/10.1021/JACS.0C11397
Abstract: The pursuit of two-dimensional (2D) borides, MBenes, has proven to be challenging, not the least because of the lack of a suitable precursor prone to the deintercalation. Here, we studied room-temperature topochemical deintercalation of lithium from the layered polymorphs of the LiNiB compound with a considerable amount of Li stored in between [NiB] layers (33 at. % Li). Deintercalation of Li leads to novel metastable borides (Li similar to 0.5NiB) with unique crystal structures. Partial removal of Li is accomplished by exposing the parent phases to air, water, or dilute HCl under ambient conditions. Scanning transmission electron microscopy and solid-state Li-7 and B-1(1) NMR spectroscopy, combined with X-ray pair distribution function (PDF) analysis and DFT calculations, were utilized to elucidate the novel structures of (Li similar to 0.5NiB) and the mechanism of Li-deintercalation. We have shown that the deintercalation of Li proceeds via a “zip-lock” mechanism, leading to the condensation of single [NiB] layers into double or triple layers bound via covalent bonds, resulting in structural fragments with Li[NiB](2) and Li[NiB](3) compositions. The crystal structure of Li similar to 0.5NiB is best described as an intergrowth of the ordered single [NiB], double [NiB](2), or triple [NiB](3) layers alternating with single Li layers; this explains its structural complexity. The formation of double or triple [NiB] layers induces a change in the magnetic behavior from temperature-independent paramagnets in the parent LiNiB compounds to the spin-glassiness in the deintercalated Li similar to 0.5NiB counterparts. LiNiB compounds showcase the potential to access a plethora of unique materials, including 2D MBenes (NiB).
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
DOI: 10.1021/JACS.0C11397
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“Creation of Exclusive Artificial Cluster Defects by Selective Metal Removal in the (Zn, Zr) Mixed-Metal UiO-66”. Feng X, Jena HS, Krishnaraj C, Arenas-Esteban D, Leus K, Wang G, Sun J, Rüscher M, Timoshenko J, Roldan Cuenya B, Bals S, Voort PVD, Journal Of The American Chemical Society , jacs.1c05357 (2021). http://doi.org/10.1021/jacs.1c05357
Abstract: The differentiation between missing linker defects
and missing cluster defects in MOFs is difficult, thereby limiting the
ability to correlate materials properties to a specific type of defects.
Herein, we present a novel and easy synthesis strategy for the
creation of solely “missing cluster defects” by preparing mixed-metal
(Zn, Zr)-UiO-66 followed by a gentle acid wash to remove the Zn
nodes. The resulting material has the reo UiO-66 structure, typical
for well-defined missing cluster defects. The missing clusters are
thoroughly characterized, including low-pressure Ar-sorption, iDPCSTEM
at a low dose (1.5 pA), and XANES/EXAFS analysis. We
show that the missing cluster UiO-66 has a negligible number of missing linkers. We show the performance of the missing cluster
UiO-66 in CO2 sorption and heterogeneous catalysis.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 29
DOI: 10.1021/jacs.1c05357
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