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“A simple method to clean ligand contamination on TEM grids”. Li C, Tardajos AP, Wang D, Choukroun D, Van Daele K, Breugelmans T, Bals S, Ultramicroscopy 221, 113195 (2021). http://doi.org/10.1016/j.ultramic.2020.113195
Abstract: Colloidal nanoparticles (NPs) including nanowires and nanosheets made by chemical methods involve many organic ligands. When the structure of NPs is investigated via transmission electron microscopy (TEM), the organic ligands act as a source for e-beam induced deposition and this causes substantial build-up of carbon layers in the investigated areas, which is typically referred to as “contamination” in the eld of electron mi- croscopy. This contamination is often more severe for scanning TEM, a technique that is based on a focused electron beam and hence higher electron dose rate. In this paper, we report a simple and effective method to clean drop-cast TEM grids that contain NPs with ligands. Using a combination of activated carbon and ethanol, this method effectively reduces the amount of ligands on TEM grids, and therefore greatly improves the quality of electron microscopy images and subsequent analytical measurements. This ef cient and facile method can be helpful during electron microscopy investigation of different kinds of nanomaterials that suffer from ligand- induced contamination.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 2.843
Times cited: 10
DOI: 10.1016/j.ultramic.2020.113195
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“Photoresistive gas sensor based on nanocrystalline ZnO sensitized with colloidal perovskite CsPbBr3 nanocrystals”. Chizhov As, Rumyantseva Mn, Drozdov Ka, Krylov Iv, Batuk M, Hadermann J, Filatova Dg, Khmelevsky No, Kozlovsky Vf, Maltseva Ln, Gaskov Am, Sensors And Actuators B-Chemical 329, 129035 (2021). http://doi.org/10.1016/j.snb.2020.129035
Abstract: The development of sensor materials of which gas sensitivity activates under light illumination is of great importance for the design of portable gas analyzers with low power consumption. In the present work a ZnO/CsPbBr3 nanocomposite based on nanocrystalline ZnO and colloidal cubic-shaped perovskite CsPbBr3 nanocrystals (NCs) capped by oleic acide and oleylamine was synthesized. The individual materials and obtained nanocomposite are characterized by x-ray diffraction, low-temperature nitrogen adsorption, x-ray photoelectron spectroscopy, high angle annular dark field scanning transmission electron microscopy with energy-dispersive Xray spectroscopy mapping and UV-vis absorption spectroscopy. The spectral dependence of the photoconductivity of the ZnO/CsPbBr3 nanocomposite reveals a well-defined peak that strongly correlates with the its optical absorption spectrum. The nanocomposite ZnO/CsPbBr3 shows enhanced photoresponse under visible light illumination (lambda(max) = 470 nm, 8 mW/cm(2)) in air, oxygen and argone, compared with pure nanocrystalline ZnO. Under periodic illumination in the temperature range of 25-100 degrees C, the ZnO/CsPbBr3 nanocomposite shows a sensor response to 0.5-3.0 ppm NO2, unlike pure nanocrystalline ZnO matrix, which demonstrates sensor sensitivity to NO2 under the same conditions above 100 degrees C. The effects of humidity on the sensor signal and photoresponse are also discussed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.401
DOI: 10.1016/j.snb.2020.129035
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“Can leaf shape be represented by the ratio of leaf width to length? Evidence from nine species of Magnolia and Michelia (Magnoliaceae)”. Shi P, Yu K, Niinemets Ü, Gielis J, Forests 12, 41 (2021). http://doi.org/10.3390/F12010041
Abstract: Leaf shape is closely related to economics of leaf support and leaf functions, including light interception, water use, and CO2 uptake, so correct quantification of leaf shape is helpful for studies of leaf structure/function relationships. There are some extant indices for quantifying leaf shape, including the leaf width/length ratio (W/L), leaf shape fractal dimension (FD), leaf dissection index, leaf roundness index, standardized bilateral symmetrical index, etc. W/L ratio is the simplest to calculate, and recent studies have shown the importance of the W/L ratio in explaining the scaling exponent of leaf dry mass vs. leaf surface area and that of leaf surface area vs. leaf length. Nevertheless, whether the W/L ratio could reflect sufficient geometrical information of leaf shape has been not tested. The FD might be the most accurate measure for the complexity of leaf shape because it can characterize the extent of the self-similarity and other planar geometrical features of leaf shape. However, it is unknown how strongly different indices of leaf shape complexity correlate with each other, especially whether W/L ratio and FD are highly correlated. In this study, the leaves of nine Magnoliaceae species (>140 leaves for each species) were chosen for the study. We calculated the FD value for each leaf using the box-counting approach, and measured leaf fresh mass, surface area, perimeter, length, and width. We found that FD is significantly correlated to the W/L ratio and leaf length. However, the correlation between FD and the W/L ratio was far stronger than that between FD and leaf length for each of the nine species. There were no strong correlations between FD and other leaf characteristics, including leaf area, ratio of leaf perimeter to area, fresh mass, ratio of leaf fresh mass to area, and leaf roundness index. Given the strong correlation between FD and W/L, we suggest that the simpler index, W/L ratio, can provide sufficient information of leaf shape for similarly-shaped leaves. Future studies are needed to characterize the relationships among FD and W/L in leaves with strongly varying shape, e.g., in highly dissected leaves.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 1.951
DOI: 10.3390/F12010041
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“Seeded growth combined with cation exchange for the synthesis of anisotropic Cu2-xS/ZnS, Cu2-xS, and CuInS2 nanorods”. Xia C, Pedrazo-Tardajos A, Wang D, Meeldijk JD, Gerritsen HC, Bals S, de Donega CM, Chemistry of materials 33, 102 (2021). http://doi.org/10.1021/ACS.CHEMMATER.0C02817
Abstract: Colloidal copper(I) sulfide (Cu2-xS) nanocrystals (NCs) have attracted much attention for a wide range of applications because of their unique optoelectronic properties, driving scientists to explore the potential of using Cu2-xS NCs as seeds in the synthesis of heteronanocrystals to achieve new multifunctional materials. Herein, we developed a multistep synthesis strategy toward Cu2-xS/ZnS heteronanorods. The Janus-type Cu2-xS/ZnS heteronanorods are obtained by the injection of hexagonal high-chalcocite Cu2-xS seed NCs in a hot zinc oleate solution in the presence of suitable surfactants, 20 s after the injection of sulfur precursors. The Cu2-xS seed NCs undergo rapid aggregation and coalescence in the first few seconds after the injection, forming larger NCs that act as the effective seeds for heteronucleation and growth of ZnS. The ZnS heteronucleation occurs on a single (100) facet of the Cu2-xS seed NCs and is followed by fast anisotropic growth along a direction that is perpendicular to the c-axis, thus leading to Cu2-xS/ZnS Janus-type heteronanorods with a sharp heterointerface. Interestingly, the high-chalcocite crystal structure of the injected Cu2-xS seed NCs is preserved in the Cu2-xS segments of the heteronanorods because of the highthermodynamic stability of this Cu2-xS phase. The Cu2-xS/ZnS heteronanorods are subsequently converted into single-component Cu2-xS and CuInS2 nanorods by postsynthetic topotactic cation exchange. This work expands the possibilities for the rational synthesis of colloidal multicomponent heteronanorods by allowing the design principles of postsynthetic heteroepitaxial seeded growth and nanoscale cation exchange to be combined, yielding access to a plethora of multicomponent heteronanorods with diameters in the quantum confinement regime.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 10
DOI: 10.1021/ACS.CHEMMATER.0C02817
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“Confinement and edge effects on atomic collapse in graphene nanoribbons”. Wang J, Van Pottelberge R, Jacobs A, Van Duppen B, Peeters FM, Physical Review B 103, 035426 (2021). http://doi.org/10.1103/PHYSREVB.103.035426
Abstract: Atomic collapse in graphene nanoribbons behaves in a fundamentally different way as compared to monolayer graphene due to the presence of multiple energy bands and the effect of edges. For armchair nanoribbons we find that bound states gradually transform into atomic collapse states with increasing impurity charge. This is very different in zigzag nanoribbons where multiple quasi-one-dimensional bound states are found that originates from the zero-energy zigzag edge states. They are a consequence of the flat band and the electron distribution of these bound states exhibits two peaks. The lowest-energy edge state transforms from a bound state into an atomic collapse resonance and shows a distinct relocalization from the edge to the impurity position with increasing impurity charge.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 10
DOI: 10.1103/PHYSREVB.103.035426
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“Hydration effects and negative dielectric constant of nano-confined water between cation intercalated MXenes”. Jalali H, Khoeini F, Peeters FM, Neek-Amal M, Nanoscale 13, 922 (2021). http://doi.org/10.1039/D0NR03953E
Abstract: Using electrochemical methods a profound enhancement of the capacitance of electric double layer capacitor electrodes was reported when water molecules are strongly confined into the two-dimensional slits of titanium carbide MXene nanosheets [A. Sugahara et al., Nat. Commun., 2019, 10, 850]. We study the effects of hydration on the dielectric properties of nanoconfined water and supercapacitance properties of the cation intercalated MXene. A model for the electric double layer capacitor is constructed where water molecules are strongly confined in two-dimensional slits of MXene. We report an abnormal dielectric constant and polarization of nano-confined water between MXene layers. We found that by decreasing the ionic radius of the intercalated cations and in a critical hydration shell radius the capacitance of the system increases significantly (similar or equal to 200 F g(-1)) which can be interpreted as a negative permittivity. This study builds a bridge between the fundamental understanding of the dielectric properties of nanoconfined water and the capability of using MXene films for supercapacitor technology, and in doing so provides a solid theoretical support for recent experiments.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 7.367
Times cited: 7
DOI: 10.1039/D0NR03953E
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“Morphological and elemental characterization of leaf-deposited particulate matter from different source types : a microscopic investigation”. Castanheiro A, Wuyts K, Hofman J, Nuyts G, De Wael K, Samson R, Environmental Science And Pollution Research 28, 25716 (2021). http://doi.org/10.1007/S11356-021-12369-Z
Abstract: Particulate matter (PM) deposition on urban green enables the collection of particulate pollution from a diversity of contexts, and insight into the physico-chemical profiles of PM is key for identifying main polluting sources. This study reports on the morphological and elemental characterization of PM2-10 deposited on ivy leaves from five different environments (forest, rural, roadside, train, industry) in the region of Antwerp, Belgium. Ca. 40,000 leaf-deposited particles were thoroughly investigated by particle-based analysis using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDX) and their physico-chemical characteristics were explored for PM source apportionment purposes. The size distribution of all deposited particles was biased towards small-sized PM, with 32% of the particles smaller than 2.5 mu m (PM2.5) and median diameters of 2.80-3.09 mu m. The source type influenced both the particles' size and morphology (aspect ratio and shape), with roadside particles being overall the smallest in size and the most spherical. While forest and rural elemental profiles were associated with natural PM, the industry particles revealed the highest anthropogenic metal input. PM2-10 profiles for roadside and train sites were rather comparable and only distinguishable when evaluating the fine (2-2.5 mu m) and coarse (2.5-10 mu m) PM fractions separately, which enabled the identification of a larger contribution of combustion-derived particles (small, circular, Fe-enriched) at the roadside compared to the train. Random forest prediction model classified the source type correctly for 61-85% of the leaf-deposited PM. The still modest classification accuracy denotes the influence of regional background PM and demands for additional fingerprinting techniques to facilitate source apportionment. Nonetheless, the obtained results demonstrate the utility of leaf particle-based analysis to fingerprint and pinpoint source-specific PM, particularly when considering both the composition and size of leaf-deposited particles.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 2.741
DOI: 10.1007/S11356-021-12369-Z
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“Critical behavior of the ferromagnets CrI₃, CrBr₃, and CrGeTe₃, and the antiferromagnet FeCl₂, : a detailed first-principles study”. Tiwari S, Van de Put ML, Sorée B, Vandenberghe WG, Physical Review B 103, 014432 (2021). http://doi.org/10.1103/PHYSREVB.103.014432
Abstract: We calculate the Curie temperature of layered ferromagnets, chromium tri-iodide (CrI3), chromium tri-bromide (CrBr3), chromium germanium tri-telluride (CrGeTe3), and the Ned temperature of a layered antiferromagnet iron di-chloride (FeCl2), using first-principles density functional theory calculations and Monte Carlo simulations. We develop a computational method to model the magnetic interactions in layered magnetic materials and calculate their critical temperature. We provide a unified method to obtain the magnetic exchange parameters (J) for an effective Heisenberg Hamiltonian from first principles, taking into account both the magnetic ansiotropy as well as the out-of-plane interactions. We obtain the magnetic phase change behavior, in particular the critical temperature, from the susceptibility and the specific-heat, calculated using the three-dimensional Monte Carlo (METROPOLIS) algorithm. The calculated Curie temperatures for ferromagnetic materials (CrI3, CrBr3, and CrGeTe3), match well with experimental values. We show that the interlayer interaction in bulk CrI3 with R (3) over bar stacking is significantly stronger than the C2/m stacking, in line with experimental observations. We show that the strong interlayer interaction in R (3) over bar CrI3 results in a competition between the in-plane and the out-of-plane magnetic easy axes. Finally, we calculate the Ned temperature of FeCl2 to be 47 +/- 8 K and show that the magnetic phase transition in FeCl2 occurs in two steps with a high-temperature intralayer ferromagnetic phase transition and a low-temperature interlayer antiferromagnetic phase transition.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
DOI: 10.1103/PHYSREVB.103.014432
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“Impact of ordering on the reactivity of mixed crystals of topological insulators with anion substitution: Bi₂SeTe₂, and Sb₂SeTe₂”. Volykhov AA, Frolov AS, Neudachina VS, Vladimirova NV, Gerber E, Callaert C, Hadermann J, Khmelevsky NO, Knop-Gericke A, Sanchez-Barriga J, Yashina LV, Applied Surface Science 541, 148490 (2021). http://doi.org/10.1016/J.APSUSC.2020.148490
Abstract: Three-dimensional topological insulators are exotic materials with unique properties. Tetradymite type binary chalcogenides of bismuth and antimony, as well as their mixed crystals, belong to prototypical TIs. Potential device applications of these materials require in-depth knowledge of their stability in the ambient atmosphere and other media maintained during their processing. Here we investigated the reactivity of mixed crystals with anion substitution, Bi-2(Se1-xTex)(3) and Sb2(Se1-xTex)(3), towards molecular oxygen using both in situ and ex situ X-ray photoelectron spectroscopy. The results indicate that, in contrast to cation substitution, partial substitution of tellurium by selenium atoms leads to anomalously high surface reactivity, which even exceeds that of the most reactive binary constituent. We attribute this effect to anion ordering that essentially modifies the bond geometry, especially the respective bond angles as modeled by DFT.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.387
DOI: 10.1016/J.APSUSC.2020.148490
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“Mn₂O₃, oxide with bixbyite structure for the electrochemical oxygen reduction reaction in alkaline media : highly active if properly manipulated”. Ryabova AS, Istomin SY, Dosaev KA, Bonnefont A, Hadermann J, Arkharova NA, Orekhov AS, Sena RP, Saveleva VA, Kerangueven G, Antipov E V, Savinova ER, Tsirlina GA, Electrochimica Acta 367, 137378 (2021). http://doi.org/10.1016/J.ELECTACTA.2020.137378
Abstract: We consider compositional and structural factors which can affect the activity of bixbyite alpha-Mn2O3 towards the oxygen reduction reaction (ORR) and the stability of this oxide in alkaline solution. We compare electrochemistry of undoped, Fe and Al-doped alpha-Mn2O3 with bixbyite structure and braunite Mn7SiO12 having bixbyite-related crystal structure, using the rotating disk electrode (RDE), the rotating ring-disk electrode (RRDE), and cyclic voltammetry (CV) techniques. All manganese oxides under study are stable in the potential range between the ORR onset and ca. 0.7 V vs. Reversible Hydrogen Electrode (RHE). It is found that any changes introduced in the bixbyite structure and/or composition of alpha-Mn2O3 lead to an activity drop in both the oxygen reduction and hydrogen peroxide reactions in this potential interval. For the hydrogen peroxide reduction reaction these modifications also result in a change in the nature of the rate-determining step. The obtained results confirm that due to its unique crystalline structure undoped alpha-Mn2O3 is the most ORR active (among currently available) Mn oxide catalyst and favor the assumption of the key role of the (111) surface of alpha-Mn2O3 in the very high activity of this material towards the ORR. (C) 2020 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.798
DOI: 10.1016/J.ELECTACTA.2020.137378
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“Local conversion of redox inactive molecules into redox active ones : a formaldehyde based strategy for the electrochemical detection of illicit drugs containing primary and secondary amines”. Schram J, Thiruvottriyur Shanmugam S, Sleegers N, Florea A, Samyn N, van Nuijs ALN, De Wael K, Electrochimica Acta 367, 137515 (2021). http://doi.org/10.1016/J.ELECTACTA.2020.137515
Abstract: Electrochemical techniques have evidenced to be highly suitable for the development of portable, rapid and accurate screening methods for the detection of illicit drugs in seized samples. However, the redox inactivity of primary amines, one of the most common functional groups of illicit drugs, masks voltammetric detection in aqueous environment at carbon electrodes and, therefore, leads to false negative results if only these primary amines are present in the structures. This work explores the feasibility of a derivatisation approach that introduces formaldehyde in the measuring conditions in order to achieve methylation, via an Eschweiler-Clarke mechanism, of illicit drugs containing primary and secondary amines, using amphetamine (AMP) and methamphetamine (MET) as model molecules. As a result the electrochemical fingerprint is enriched and thereby the detectability enhanced. A combination of liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOFMS) and square-wave voltammetric (SWV) measurements is employed to identify reaction products and link them to the observed redox peaks. Although an alkaline environment (pH 12.0) proved to increase the reaction yield, a richer electrochemical fingerprint (EF) is obtained in neutral conditions (pH 7.0). Similarly, the addition of formate improved the reaction conversion but reduced the EF by eliminating a redox peak that is attributed to side products formed in the absence of formate. To illustrate the applicability, the derivatisation strategy is applied to several prominent illicit drugs containing primary and secondary amines to demonstrate its EF enriching capabilities. Finally, real street samples from forensic seizures are analysed. Overall, this strategy unlocks the detectability of the hitherto undetectable AMP and other drugs only containing primary amines, while strongly facilitating the identification of MET and analogues. These findings are not limited to illicit drugs, the insights can ultimately be applied to other target molecules containing similar functional groups. (C) 2020 Published by Elsevier Ltd.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre
Impact Factor: 4.798
DOI: 10.1016/J.ELECTACTA.2020.137515
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“Electronic and magnetic properties of single-layer FeCl₂, with defects”. Ceyhan E, Yagmurcukardes M, Peeters FM, Sahin H, Physical Review B 103, 014106 (2021). http://doi.org/10.1103/PHYSREVB.103.014106
Abstract: The formation of lattice defects and their effect on the electronic properties of single-layer FeCl2 are investigated by means of first-principles calculations. Among the vacancy defects, namely mono-, di-, and three-Cl vacancies and mono-Fe vacancy, the formation of mono-Cl vacancy is the most preferable. Comparison of two different antisite defects reveals that the formation of the Fe-antisite defect is energetically preferable to the Cl-antisite defect. While a single Cl vacancy leads to a 1 mu(B) decrease in the total magnetic moment of the host lattice, each Fe vacant site reduces the magnetic moment by 4 mu(B). However, adsorption of an excess Cl atom on the surface changes the electronic structure to a ferromagnetic metal or to a ferromagnetic semiconductor depending on the adsorption site without changing the ferromagnetic state of the host lattice. Both Cl-antisite and Fe-antisite defected domains change the magnetic moment of the host lattice by -1 mu(B) and +3 mu(B), respectively. The electronic ground state of defected structures reveals that (i) single-layer FeCl2 exhibits half-metallicity under the formation of vacancy and Cl-antisite defects; (ii) ferromagnetic metallicity is obtained when a single Cl atom is adsorbed on upper-Cl and Fe sites, respectively; and (iii) ferromagnetic semiconducting behavior is found when a Cl atom is adsorbed on a lower-Cl site or a Fe-antisite defect is formed. Simulated scanning electron microscope images show that atomic-scale identification of defect types is possible from their electronic charge density. Further investigation of the periodically Fe-defected structures reveals that the formation of the single-layer FeCl3 phase, which is a dynamically stable antiferromagnetic semiconductor, is possible. Our comprehensive analysis on defects in single-layer FeCl2 will complement forthcoming experimental observations.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 7
DOI: 10.1103/PHYSREVB.103.014106
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“Direct observation of layer-stacking and oriented wrinkles in multilayer hexagonal boron nitride”. Chen L, Elibol K, Cai H, Jiang C, Shi W, Chen C, Wang HS, Wang X, Mu X, Li C, Watanabe K, Taniguchi T, Guo Y, Meyer JC, Wang H, 2d Materials 8, 024001 (2021). http://doi.org/10.1088/2053-1583/ABD41E
Abstract: Hexagonal boron nitride (h-BN) has long been recognized as an ideal substrate for electronic devices due to its dangling-bond-free surface, insulating nature and thermal/chemical stability. These properties of the h-BN multilayer are mainly determined by its lattice structure. Therefore, to analyse the lattice structure and orientation of h-BN crystals becomes important. Here, the stacking order and wrinkles of h-BN are investigated by transmission electron microscopy. It is experimentally confirmed that the layers in the h-BN flakes are arranged in the AA ' stacking. The wrinkles in a form of threefold network throughout the h-BN crystal are oriented along the armchair direction, and their formation mechanism was further explored by molecular dynamics simulations. Our findings provide a deep insight about the microstructure of h-BN and shed light on the structural design/electronic modulations of two-dimensional crystals.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.937
DOI: 10.1088/2053-1583/ABD41E
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“First-principles discovery of stable two-dimensional materials with high-level piezoelectric response”. Kocabas T, Cakir D, Sevik C, Journal Of Physics-Condensed Matter 33, 115705 (2021). http://doi.org/10.1088/1361-648X/ABD3DA
Abstract: The rational design of two-dimensional (2D) piezoelectric materials has recently garnered great interest due to their increasing use in technological applications, including sensor technology, actuating devices, energy harvesting, and medical applications. Several materials possessing high piezoelectric response have been reported so far, but a high-throughput first-principles approach to estimate the piezoelectric potential of layered materials has not been performed yet. In this study, we systematically investigated the piezoelectric (e(11), d(11)) and elastic (C-11 and C-12) properties of 128 thermodynamically stable 2D semiconductor materials by employing first-principle methods. Our high-throughput approach demonstrates that the materials containing Group-V elements produce significantly high piezoelectric strain constants, d(11) > 40 pm V-1, and 49 of the materials considered have the e(11) coefficient higher than MoS2 insomuch as BrSSb has one of the largest d(11) with a value of 373.0 pm V-1. Moreover, we established a simple empirical model in order to estimate the d(11) coefficients by utilizing the relative ionic motion in the unit cell and the polarizability of the individual elements in the compounds.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
DOI: 10.1088/1361-648X/ABD3DA
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“Farmers' decision to use drought early warning system in developing countries”. Sharafi L, Zarafshani K, Keshavarz M, Azadi H, Van Passel S, Science Of The Total Environment 758, 142761 (2021). http://doi.org/10.1016/J.SCITOTENV.2020.142761
Abstract: Drought is a persistent, sluggish natural disaster in developing countries that has generated a financial burden and an unstable climate. Farmers should adopt early warning systems (EWS) in their strategies for monitoring drought to reduce its serious consequences. However, farmers in developing countries are reluctant to use EWS as their management strategies. Hence, the aim of this study was to investigate the decision of farmers to use climate knowledge through the model of farming activity in Kermanshah Township, Iran. A surveyor questionnaire was used to gather data from 370 wheat farmers using random sampling methods inmulti-stage clusters. Results revealed that the decision to use climate information is affected by personal factors, attitude towards climate information, objectives of using climate information, and external/physical farming factors. The result of this study has implications for drought management practitioners. To be specific, the results can aid policymakers to design early alert programs to minimize the risk of drought and thus move from conventional to climate smart agriculture. (C) 2020 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering Management (ENM)
Impact Factor: 4.9
DOI: 10.1016/J.SCITOTENV.2020.142761
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“Soot removal from ancient Egyptian complex painted surfaces using a double network gel : empirical tests on the ceiling of the sanctuary of Osiris in the temple of Seti I-Abydos”. Al-Emam E, Motawea AG, Caen J, Janssens K, Heritage science 9, 1 (2021). http://doi.org/10.1186/S40494-020-00473-1
Abstract: In this study, we evaluated the ease of removal of soot layers from ancient wall paintings by employing double network gels as a controllable and safe cleaning method. The ceiling of the temple of Seti I (Abydos, Egypt) is covered with thick layers of soot; this is especially the case in the sanctuary of Osiris. These layers may have been accumulated during the occupation of the temple by Christians, fleeing the Romans in the first centuries A.D. Soot particulates are one of the most common deposits to be removed during conservation-restoration activities of ancient Egyptian wall paintings. They usually mask the painted reliefs and reduce the permeability of the painted surface. A Polyvinyl alcohol-borax/agarose (PVA-B/AG) double network gel was selected for this task since its properties were expected to be compatible with the cleaning treatment requirements. The gel is characterized by its flexibility, permitting to take the shape of the reliefs, while also having self-healing properties, featuring shape stability and an appropriate capacity to retain liquid. The gel was loaded with several cleaning reagents that proved to be effective for soot removal. Soot removal tests were conducted with these gel composites. The cleaned surfaces were evaluated with the naked eye, a digital microscope, and color measurements in order to select the best gel composite. The gel composite, loaded with a solution of 5% ammonia, 0.3% ammonium carbonate, and 0.3% EDTA yielded the most satisfactory results and allowed to safely remove a crust of thick soot layers from the surface. Thus, during the final phase of the study, it was used successfully to clean a larger area of the ceiling.
Keywords: A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
DOI: 10.1186/S40494-020-00473-1
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“Reversible ratchet effects in a narrow superconducting ring”. Jiang J, Wang Y-L, Milošević, MV, Xiao Z-L, Peeters FM, Chen Q-H, Physical Review B 103, 014502 (2021). http://doi.org/10.1103/PHYSREVB.103.014502
Abstract: We study the ratchet effect in a narrow pinning-free superconductive ring based on time-dependent Ginzburg-Landau (TDGL) equations. Voltage responses to external dc and ac currents at various magnetic fields are studied. Due to asymmetric barriers for flux penetration and flux exit in the ring-shaped superconductor, the critical current above which the flux-flow state is reached, as well as the critical current for the transition to the normal state, are different for the two directions of applied current. These effects cooperatively cause ratchet signal reversal at high magnetic fields, which has not been reported to date in a pinning-free system. The ratchet signal found here is larger than those induced by asymmetric pinning potentials. Our results also demonstrate the feasibility of using mesoscopic superconductors to employ a superconducting diode effect in versatile superconducting devices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 4
DOI: 10.1103/PHYSREVB.103.014502
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“Guidelines for passive control of traffic-related air pollution in street canyons : an overview for urban planning”. Voordeckers D, Lauriks T, Denys S, Billen P, Tytgat T, Van Acker M, Landscape And Urban Planning 207, 103980 (2021). http://doi.org/10.1016/J.LANDURBPLAN.2020.103980
Abstract: Recent studies indicate the necessity of addressing traffic-related air pollution in urban environments, as street canyons are known for their lack of natural ventilation and increased pollution levels. To address this issue, numerous studies have been conducted on different aspects (e.g. aspect ratio, orientation and height variation) and their impact on ventilation and pollution dispersion/dilution performance in street canyons. Despite the numerous studies, the information remains fragmented and the results and applications are fairly unknown in urban planning. Broad review studies on numerous street canyon aspects are also quite scarce. In this study, over 200 studies were collected and reviewed across various parameters and on different configuration levels (street canyon configuration / building configuration / in-canyon configuration). Hereby, the study aims to give a comprehensive overview and to formulate spatial guidelines to improve the application of the reviewed studies for the purpose of urban planning. In total, 19 general guidelines were formulated, and an implementation strategy for the purpose of urban planning was developed. Despite the usability of these guidelines for urban planning, a high number of limitations and variabilities were detected. The broad literature review also revealed knowledge gaps, indicating the potentials for further research.
Keywords: A1 Journal article; Economics; Law; Engineering sciences. Technology; Art; Energy and Materials in Infrastructure and Buildings (EMIB); Research Group for Urban Development; Sustainable Energy, Air and Water Technology (DuEL); Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)
Impact Factor: 4.563
DOI: 10.1016/J.LANDURBPLAN.2020.103980
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“An attempt to develop ecotourism in an unknown area : the case of Nehbandan County, South Khorasan Province, Iran”. Ghorbani A, Mousazadeh H, Taheri F, Ehteshammajd S, Azadi H, Yazdanpanah M, Khajehshahkohi A, Tanaskovik V, Van Passel S, Environment, development and sustainability 23, 11792 (2021). http://doi.org/10.1007/S10668-020-01142-W
Abstract: This study is an attempt to develop ecotourism in Nehbandan County, in the South Khorasan Province, Iran, by representing unknown areas that have tourism potential. The most important obstacle in the development of tourism industry is the lack of strong marketing plans, tourism management, accommodations for overnight and long stays, and medical and health clinic in the desert. This is a qualitative, exploratory case study investigating the status of environmental, sociocultural, and economic impacts of ecotourism development on the native people's livelihood in Nehbandan County in Iran. The methodology is based on field observations, secondary data sources, and field survey. It is an interpretive approach that avoids numbers but focuses on issues linked to culture and nature. In the present study, the grounded theory was used to perform data analysis. Based on the findings, ecotourism has undoubtedly proven to be an effective environmental conservation tool in the study site and enables local people to increase their livelihood security through employment in activities relating to ecotourism and the development of rural livelihood.
Keywords: A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM)
DOI: 10.1007/S10668-020-01142-W
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“A systematic comparison of commercially produced struvite : quantities, qualities and soil-maize phosphorus availability”. Muys M, Phukan R, Brader G, Samad A, Moretti M, Haiden B, Pluchon S, Roest K, Vlaeminck SE, Spiller M, Science Of The Total Environment 756, 143726 (2021). http://doi.org/10.1016/J.SCITOTENV.2020.143726
Abstract: Production of struvite (MgNH4PO4·6H2O) from waste streams is increasingly implemented to recover phosphorus (P), which is listed as a critical raw material in the European Union (EU). To facilitate EU-wide trade of P-containing secondary raw materials such as struvite, the EU issued a revised fertilizer regulation in 2019. A comprehensive overview of the supply of struvite and its quality is presently missing. This study aimed: i) to determine the current EU struvite production volumes, ii) to evaluate all legislated physicochemical characteristics and pathogen content of European struvite against newly set regulatory limits, and iii) to compare not-regulated struvite characteristics. It is estimated that in 2020, between 990 and 1250 ton P are recovered as struvite in the EU. Struvite from 24 European production plants, accounting for 30% of the 80 struvite installations worldwide was sampled. Three samples failed the physicochemical legal limits; one had a P content of <7% and three exceeded the organic carbon content of 3% dry weight (DW). Mineralogical analysis revealed that six samples had a struvite content of 80–90% DW, and 13 samples a content of >90% DW. All samples showed a heavy metal content below the legal limits. Microbiological analyses indicated that struvite may exceed certain legal limits. Differences in morphology and particle size distribution were observed for struvite sourced from digestate (rod shaped; transparent; 82 mass% < 1 mm), dewatering liquor (spherical; opaque; 65 mass% 1–2 mm) and effluent from upflow anaerobic sludge blanket reactor processing potato wastewater (spherical; opaque; 51 mass% < 1 mm and 34 mass% > 2 mm). A uniform soil-plant P-availability pattern of 3.5–6.5 mg P/L soil/d over a 28 days sampling period was observed. No differences for plant biomass yield were observed. In conclusion, the results highlight the suitability of most struvite to enter the EU fertilizer market.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Engineering Management (ENM)
Impact Factor: 4.9
DOI: 10.1016/J.SCITOTENV.2020.143726
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“Magnetic properties and critical behavior of magnetically intercalated WSe₂, : a theoretical study”. Reyntjens PD, Tiwari S, van de Put ML, Sorée B, Vandenberghe WG, 2d Materials 8, 025009 (2021). http://doi.org/10.1088/2053-1583/ABD1CC
Abstract: Transition metal dichalcogenides, intercalated with transition metals, are studied for their potential applications as dilute magnetic semiconductors. We investigate the magnetic properties of WSe2 doped with third-row transition metals (Co, Cr, Fe, Mn, Ti and V). Using density functional theory in combination with Monte Carlo simulations, we obtain an estimate of the Curie or Neel temperature. We find that the magnetic ordering is highly dependent on the dopant type. While Ti and Cr-doped WSe2 have a ferromagnetic ground state, V, Mn, Fe and Co-doped WSe2 are antiferromagnetic in their ground state. For Fe doped WSe2, we find a high Curie-temperature of 327 K. In the case of V-doped WSe2, we find that there are two distinct magnetic phase transitions, originating from a frustrated in-plane antiferromagnetic exchange interaction and a ferromagnetic out-of-plane interaction. We calculate the formation energy and reveal that, in contrast to earlier reports, the formation energy is positive for the intercalated systems studied here. We also show that in the presence of W-vacancies, it becomes favorable for Ti, Fe, and Co to intercalate in WSe2.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 6.937
Times cited: 1
DOI: 10.1088/2053-1583/ABD1CC
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“Aptamer-ligand recognition studied by native ion mobility-mass spectrometry”. Daems E, Dewaele D, Barylyuk K, De Wael K, Sobott F, Talanta 224, 121917 (2021). http://doi.org/10.1016/J.TALANTA.2020.121917
Abstract: The range of applications for aptamers, small oligonucleotide-based receptors binding to their targets with high specificity and affinity, has been steadily expanding. Our understanding of the mechanisms governing aptamer-ligand recognition and binding is however lagging, stymieing the progress in the rational design of new aptamers and optimization of the known ones. Here we demonstrate the capabilities and limitations of native ion mobility-mass spectrometry for the analysis of their higher-order structure and non-covalent interactions. A set of related cocaine-binding aptamers, displaying a range of folding properties and ligand binding affinities, was used as a case study in both positive and negative electrospray ionization modes. Using carefully controlled experimental conditions, we probed their conformational behavior and interactions with the high-affinity ligand quinine as a surrogate for cocaine. The ratios of bound and unbound aptamers in the mass spectra were used to rank them according to their apparent quinine-binding affinity, qualitatively matching the published ranking order. The arrival time differences between the free aptamer and aptamer-quinine complexes were consistent with a small ligand-induced conformational change, and found to inversely correlate with the affinity of binding. This mass spectrometry-based approach provides a fast and convenient way to study the molecular basis of aptamer-ligand recognition.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 4.162
DOI: 10.1016/J.TALANTA.2020.121917
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“Electro-optical and mechanical properties of Zinc antimonide (ZnSb) monolayer and bilayer : a first-principles study”. Bafekry A, Yagmurcukardes M, Shahrokhi M, Ghergherehchi M, Kim D, Mortazavi B, Applied Surface Science 540, 148289 (2021). http://doi.org/10.1016/J.APSUSC.2020.148289
Abstract: Latest synthesis of ZnSb monolayer, encouraged us to conduct density functional theory (DFT) simulations in order to study the structural, magnetic, electronic/optical and mechanical features of the sp2-hybridized honeycomb ZnSb monolayer (ML-ZnSb) and bilayer (BL-ZnSb). Our structural optimizations reveal that ML-ZnSb is an anisotropic hexagonal structure while BL-ZnSb is composed of shifted ZnSb layers which are covalently binded. ML-ZnSb is found to be a ferromagnetic metal, in contrast BL-ZnSb has a non-magnetic indirect band gap semiconducting ground state. For the in-plane polarization, first absorption peak of ML-ZnSb and BL-ZnSb confirm the absorbance of the light within the infrared domain wand visible range, respectively. Moreover, our results reveal that the layer-layer chemical bonding in BL-ZnSb significantly enhances the mechanical response of ML-ZnSb whose in-plane stiness is the smallest among all 2D materials (2DM). Notably, the strong in-plane anisotropy of ML-ZnSb in its stiness reduces in BL-ZnSb.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.387
Times cited: 1
DOI: 10.1016/J.APSUSC.2020.148289
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“Effect of zitterbewegung on the propagation of wave packets in ABC-stacked multilayer graphene : an analytical and computational approach”. Lavor IR, da Costa DR, Chaves A, Sena SHR, Farias GA, Van Duppen B, Peeters FM, Journal Of Physics-Condensed Matter 33, 095503 (2021). http://doi.org/10.1088/1361-648X/ABCD7F
Abstract: The time evolution of a low-energy two-dimensional Gaussian wave packet in ABC-stacked n-layer graphene (ABC-NLG) is investigated. Expectation values of the position (x, y) of center-of-mass and the total probability densities of the wave packet are calculated analytically using the Green's function method. These results are confirmed using an alternative numerical method based on the split-operator technique within the Dirac approach for ABC-NLG, which additionally allows to include external fields and potentials. The main features of the zitterbewegung (trembling motion) of wave packets in graphene are demonstrated and are found to depend not only on the wave packet width and initial pseudospin polarization, but also on the number of layers. Moreover, the analytical and numerical methods proposed here allow to investigate wave packet dynamics in graphene systems with an arbitrary number of layers and arbitrary potential landscapes.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 5
DOI: 10.1088/1361-648X/ABCD7F
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“Entropic and enthalpic factors determining the thermodynamics and kinetics of carbon segregation from transition metal nanoparticles”. Fukuhara S, Bal KM, Neyts EC, Shibuta Y, Carbon 171, 806 (2021). http://doi.org/10.1016/j.carbon.2020.09.059
Abstract: The free energy surface (FES) for carbon segregation from nickel nanoparticles is obtained from advanced molecular dynamics simulations. A suitable reaction coordinate is developed that can distinguish dissolved carbon atoms from segregated dimers, chains and junctions on the nanoparticle surface. Because of the typically long segregation time scale (up to ms), metadynamics simulations along the developed reaction coordinate are used to construct FES over a wide range of temperatures and carbon concentrations. The FES revealed the relative stability of different stages in the segregation process, and free energy barriers and rates of the individual steps could then be calculated and decomposed into enthalpic and entropic contributions. As the carbon concentration in the nickel nanoparticle increases, segregated carbon becomes more stable in terms of both enthalpy and entropy. The activation free energy of the reaction also decreases with the increase of carbon concentration, which can be mainly attributed to entropic effects. These insights and the methodology developed to obtain them improve our understanding of carbon segregation process across materials science in general, and the nucleation and growth of carbon nanotube in particular.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.337
DOI: 10.1016/j.carbon.2020.09.059
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“Tuning flexoelectricty and electronic properties of zig-zag graphene nanoribbons by functionalization”. Pandey T, Covaci L, Peeters FM, Carbon 171, 551 (2021). http://doi.org/10.1016/J.CARBON.2020.09.028
Abstract: The flexoelectric and electronic properties of zig-zag graphene nanoribbons are explored under mechanical bending using state of the art first principles calculations. A linear dependence of the bending induced out of plane polarization on the applied strain gradient is found. The inferior flexoelectric properties of graphene nanoribbons can be improved by more than two orders of magnitude by hydrogen and fluorine functionalization (CH and CF nanoribbons). A large out of plane flexoelectric effect is predicted for CF nanoribbons. The origin of this enhancement lies in the electro-negativity difference between carbon and fluorine atoms, which breaks the out of plane charge symmetry even for a small strain gradient. The flexoelectric effect can be further improved by co-functionalization with hydrogen and fluorine (CHF Janus-type nanoribbon), where a spontaneous out of plane dipole moment is formed even for flat nanoribbons. We also find that bending can control the charge localization of valence band maxima and therefore enables the tuning of the hole effective masses and band gaps. These results present an important advance towards the understanding of flexoelectric and electronic properties of hydrogen and fluorine functionalized graphene nanoribbons, which can have important implications for flexible electronic applications. (C) 2020 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 6.337
Times cited: 15
DOI: 10.1016/J.CARBON.2020.09.028
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“Carbon single-electron point source controlled by Coulomb blockade”. Kleshch VI, Porshyn V, Orekhov AS, Orekhov AS, Lützenkirchen-Hecht D, Obraztsov AN, Carbon 171, 154 (2021). http://doi.org/10.1016/j.carbon.2020.09.008
Abstract: The Coulomb blockade effect is commonly used in solid state electronics for the control of electron flow
at the single-particle level. Potentially, it allows the creation of single-electron point sources demanded
for prospective electron microscopy instruments and other vacuum electronics devices. Here we realize
this potential via creation of a stable point electron source composed of a carbon nanowire electrically
coupled to a diamond nanotip by a tunnel junction. Using energy spectroscopy analysis, we characterize
the electrons liberated from the nanometer scale carbon heterostructures in time and energy domains.
Our experimental results demonstrate perfect agreement with theory prediction of Coulomb oscillations
of the Fermi level in the nanowire and allow to determine the mechanisms of their suppression.
Persistence of the oscillations at room temperature, high intensity field emission with currents up to
1 mA, and other characteristics of our emitters are very promising for practical realization of coherent
single-electron guns.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.337
DOI: 10.1016/j.carbon.2020.09.008
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“Mechanisms of selective nanocarbon synthesis inside carbon nanotubes”. Khalilov U, Neyts EC, Carbon 171, 72 (2021). http://doi.org/10.1016/j.carbon.2020.08.060
Abstract: The possibility of confinement effects inside a carbon nanotube provides new application opportunities, e.g., growth of novel carbon nanostructures. However, the understanding the precise role of catalystfeedstock in the nanostructure synthesis is still elusive. In our simulation-based study, we investigate the Ni-catalyzed growth mechanism of encapsulated carbon nanostructures, viz. double-wall carbon nanotube and graphene nanoribbon, from carbon and hydrocarbon growth precursors, respectively. Specifically, we find that the tube and ribbon growth is determined by a catalyst-vs-feedstock competition effect. We compare our results, i.e., growth mechanism and structure morphology with all available theoretical and experimental data. Our calculations show that all encapsulated nanostructures contain metal (catalyst) atoms and such structures are less stable than their pure counterparts. Therefore, we study the purification mechanism of these structures. In general, this study opens a possible route to the controllable synthesis of tubular and planar carbon nanostructures for today’s nanotechnology.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.337
DOI: 10.1016/j.carbon.2020.08.060
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“Stable Janus TaSe₂, single-layers via surface functionalization”. Kahraman Z, Baskurt M, Yagmurcukardes M, Chaves A, Sahin H, Applied Surface Science 538, 148064 (2021). http://doi.org/10.1016/J.APSUSC.2020.148064
Abstract: First-principles calculations are performed in order to investigate the formation of Janus structures of single layer TaSe2. The structural optimizations and phonon band dispersions reveal that the formation and stability of hydrogenated (HTaSe2), fluorinated (FTaSe2), and the one-side hydrogenated and one-side fluorinated (Janus-HTaSe2F) single-layers are feasible in terms of their phonon band dispersions. It is shown that bare metallic single-layer TaSe2 can be turned into a semiconductor as only one of its surface is functionalized while it remains as a metal via its two surfaces functionalization. In addition, the semiconducting nature of single-layers HTaSe2 and FTaSe2 and the metallic behavior of Janus TaSe2 are found to be robust under applied uniaxal strains. Further analysis on piezoelectric properties of the predicted single-layers reveal the enhanced in-plane and out of-plane piezoelectricity via formed Janus-HTaSe2F. Our study indicates that single-layer TaSe2 is a suitable host material for surface functionalization via fluorination and hydrogenation which exhibit distinctive electronic and vibrational properties.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.387
DOI: 10.1016/J.APSUSC.2020.148064
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“The path towards efficient wide band gap thin-film kesterite solar cells with transparent back contact for viable tandem application”. Khelifi S, Brammertz G, Choubrac L, Batuk M, Yang S, Meuris M, Barreau N, Hadermann J, Vrielinck H, Poelman D, Neyts K, Vermang B, Lauwaert J, Solar Energy Materials And Solar Cells 219, 110824 (2021). http://doi.org/10.1016/j.solmat.2020.110824
Abstract: Wide band gap thin-film kesterite solar cell based on non-toxic and earth-abundant materials might be a suitable candidate as a top cell for tandem configuration in combination with crystalline silicon as a bottom solar cell. For this purpose and based on parameters we have extracted from electrical and optical characterization techniques of Cu2ZnGeSe4 absorbers and solar cells, a model has been developed to describe the kesterite top cell efficiency limitations and to investigate the different possible configurations with transparent back contact for fourterminal tandem solar cell application. Furthermore, we have studied the tandem solar cell performance in view of the band gap and the transparency of the kesterite top cell and back contact engineering. Our detailed analysis shows that a kesterite top cell with efficiency > 14%, a band gap in the range of 1.5-1.7 eV and transparency above 80% at the sub-band gaps photons energies are required to achieve a tandem cell with higher efficiency than with a single silicon solar cell.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 4.784
DOI: 10.1016/j.solmat.2020.110824
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