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“Misfit dislocation structure and thermal boundary conductance of GaN/AlN interfaces”. Sun J, Li Y, Karaaslan Y, Sevik C, Chen Y, Journal Of Applied Physics 130, 035301 (2021). http://doi.org/10.1063/5.0049662
Abstract: The structure and thermal boundary conductance of the wurtzite GaN/AlN (0001) interface are investigated using molecular dynamics simulation. Simulation results with three different empirical interatomic potentials have produced similar misfit dislocation networks and dislocation core structures. Specifically, the misfit dislocation network at the GaN/AlN interface is found to consist of pure edge dislocations with a Burgers vector of 1/3(1 (2) over bar 10) and the misfit dislocation core has an eight-atom ring structure. Although different interatomic potentials lead to different dislocation properties and thermal conductance values, all have demonstrated a significant effect of misfit dislocations on the thermal boundary conductance of the GaN/AlN (0001) interface. Published under an exclusive license by AIP Publishing.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
DOI: 10.1063/5.0049662
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“Tailoring CuO nanostructures for enhanced photocatalytic property”. Liu J, Jin J, Deng Z, Huang SZ, Hu ZY, Wang L, Wang C, Chen LH, Li Y, Van Tendeloo G, Su BL;, Journal of colloid and interface science 384, 1 (2012). http://doi.org/10.1016/j.jcis.2012.06.044
Abstract: We report on one-pot synthesis of various morphologies of CuO nanostructures. PEG200 as a structure directing reagent under the synergism of alkalinity by hydrothermal method has been employed to tailor the morphology of CuO nanostructures. The CuO products have been characterized by XRD, SEM, and TEM. The morphologies of the CuO nanostructures can be tuned from 10 (nanoseeds, nanoribbons) to 2D (nanoleaves) and to 3D (shuttle-like, shrimp-like, and nanoflowers) by changing the volume of PEG200 and the alkalinity in the reaction system. At neutral and relatively low alkalinity (OH-/Cu2+ <= 3), the addition of PEG200 can strongly influence the morphologies of the CuO nanostructures. At high alkalinity (OH/Cu2+ >= 4), PEG200 has no influence on the morphology of the CuO nanostructure. The different morphologies of the CuO nanostructures have been used for the photodecomposition of the pollutant rhodamine B (RhB) in water. The photocatalytic activity has been correlated with the different nanostructures of CuO. The 10 CuO nanoribbons exhibit the best performance on the RhB photodecomposition because of the exposed high surface energy {-121} crystal plane. The photocatalytic results show that the high energy surface planes of the CuO nanostructures mostly affect the photocatalytic activity rather than the morphology of the CuO nanostructures. Our synthesis method also shows it is possible to control the morphologies of nanostructures in a simple way. (C) 2012 Elsevier Inc. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.233
Times cited: 105
DOI: 10.1016/j.jcis.2012.06.044
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“Ultralong Cu(OH)(2) and CuO nanowire bundles: PEG200-directed crystal growth for enhanced photocatalytic performance”. Li Y, Yang X-Y, Rooke J, Van Tendeloo G, Su B-L, Journal of colloid and interface science 348, 303 (2010). http://doi.org/10.1016/j.jcis.2010.04.052
Abstract: Ultralong Cu(OH)(2) and CuO nanowire bundles with lengths ranging from tens to hundreds of micrometers have been selectively synthesized on a large scale by a facile solution-phase method, using PEG200 as growth-directing agent. The growth mechanisms were investigated by monitoring the nanowire evolution process. The results showed that under the action of PEG200 molecules, the Cu(OH)(2) and CuO nanowires were first formed through oriented attachment of colloidal particles, then through side self-assembly leading to nanowire bundles, and finally to CuO nanoleaves. PEG200 plays a critical role in the synthesis of nanowires as it not only prevents the random aggregation of colloidal particles toward CuO nanoleaves but also helps to orientate nanowire growth by the coalescence and alignment in one direction of the colloidal particles. The concentration of OH(-) in the reaction system is also important for nanowire growth. In the absence of PEG200, nanoleaves are formed by an Ostwald ripening process. The band-gap value estimated from a UV-Vis absorption spectrum of CuO nanowire bundles is 2.32 eV. The photodegradation of a model pollutant, rhodamine B, by CuO nanowires and nanoleaves was compared with commercial nanopowders, showing that the as-synthesized ultralong CuO polycrystalline nanowire bundles have an enhanced photocatalytic activity with 87% decomposition of rhodamine B after an 8-h reaction, which was much higher than that of single-crystal nanoleaves (61%) and commercial nanopowders (32%). The origin of the high photocatalytic activity of these new polycrystalline CuO nanowire bundles has been discussed. This present work reveals that the (0 0 2) crystallographic surface is more favorable for photocatalytic decomposition of organic compounds and that these ultralong CuO nanowire bundles are potential candidates for photocatalysts in wastewater treatment. (C) 2010 Elsevier Inc. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.233
Times cited: 70
DOI: 10.1016/j.jcis.2010.04.052
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“Size effect of bifunctional gold in hierarchical titanium oxide-gold-cadmium sulfide with slow photon effect for unprecedented visible-light hydrogen production”. Zhao H, Li C-F, Hu Z-Y, Liu J, Li Y, Hu J, Van Tendeloo G, Chen L-H, Su B-L, Journal Of Colloid And Interface Science 604, 131 (2021). http://doi.org/10.1016/J.JCIS.2021.06.167
Abstract: Gold nanoparticles (Au NPs) with surface plasmonic resonance (SPR) effect and excellent internal electron transfer ability have widely been combined with semiconductors for photocatalysis. However, the in-depth effects of Au NPs in multicomponent photocatalysts have not been completely understood. Herein, ternary titanium oxide-gold-cadmium sulfide (TiO2-Au-CdS, TAC) photocatalysts, based on hierarchical TiO2 inverse opal photonic crystal structure with different Au NPs sizes have been designed to reveal the SPR effect and internal electron transfer of Au NPs in the presence of slow photon effect. It appears that the SPR effect and internal electron transfer ability of Au NPs, depending on their sizes, play a synergistic effect on the photocatalytic enhancement. The ternary TAC-10 photocatalyst with – 10 nm Au NPs demonstrates an unprecedented hydrogen evolution rate of 47.6 mmolh-1g 1 under visible-light, demonstrating- 48% enhancement comparing to the sample without slow photon effect. In particular, a 9.83% apparent quantum yield under 450 nm monochromatic light is achieved for TAC-10. A model is proposed and finite-difference time-domain (FDTD) simulations reveal the size influence of Au NPs in ternary TAC photocatalysts. This work suggests that the rational design of bifunctional Au NPs coupling with slow photon effect could largely promote hydrogen production from visible-light driven water splitting. (c) 2021 Elsevier Inc. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.233
DOI: 10.1016/J.JCIS.2021.06.167
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“An elliptical blade is not a true ellipse, but a superellipse : evidence from two Michelia species”. Li Y, Niklas KJ, Gielis J, Niinemets Ü, Schrader J, Wang R, Shi P, Journal of forestry research 33, 1341 (2022). http://doi.org/10.1007/S11676-021-01385-X
Abstract: The shape of leaf laminae exhibits considerable diversity and complexity that reflects adaptations to environmental factors such as ambient light and precipitation as well as phyletic legacy. Many leaves appear to be elliptical which may represent a ‘default’ developmental condition. However, whether their geometry truly conforms to the ellipse equation (EE), i.e., (x/a)2 + (y/b)2 = 1, remains conjectural. One alternative is described by the superellipse equation (SE), a generalized version of EE, i.e., |x/a|n +|y/b|n = 1. To test the efficacy of EE versus SE to describe leaf geometry, the leaf shapes of two Michelia species (i.e., M. cavaleriei var. platypetala, and M. maudiae), were investigated using 60 leaves from each species. Analysis shows that the majority of leaves (118 out of 120) had adjusted root-mean-square errors of < 0.05 for the nonlinear fitting of SE to leaf geometry, i.e., the mean absolute deviation from the polar point to leaf marginal points was smaller than 5% of the radius of a hypothesized circle with its area equaling leaf area. The estimates of n for the two species were ˂ 2, indicating that all sampled leaves conformed to SE and not to EE. This study confirms the existence of SE in leaves, linking this to its potential functional advantages, particularly the possible influence of leaf shape on hydraulic conductance.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3
DOI: 10.1007/S11676-021-01385-X
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“Novel 3DOM BiVO4/TiO2nanocomposites for highly enhanced photocatalytic activity”. Zalfani M, van der Schueren B, Hu Z-Y, Rooke JC, Bourguiga R, Wu M, Li Y, Van Tendeloo G, Su B-L, Journal of materials chemistry A : materials for energy and sustainability 3, 21244 (2015). http://doi.org/10.1039/C5TA00783F
Abstract: Novel 3DOM BiVO4/TiO2 nanocomposites with intimate contact were for the first time synthesized by a hydrothermal method in order to elucidate their visible-light-driven photocatalytic performances. BiVO4 nanoparticles and 3DOM TiO2 inverse opal were fabricated respectively. These materials were characterized by XRD, XPS, SEM, TEM, N2 adsorption–desorption and UV-vis diffuse (UV-vis) and photoluminescence spectroscopies. As references for comparison, a physical mixture of BiVO4 nanoparticles and 3DOM TiO2 inverse opal powder (0.08 : 1), and a BiVO4/P25 TiO2 (0.08 : 1) nanocomposite made also by the hydrothermal method were prepared. The photocatalytic performance of all the prepared materials was evaluated by the degradation of rhodamine B (RhB) as a model pollutant molecule under visible light irradiation. The highly ordered 3D macroporous inverse opal structure can provide more active surface areas and increased mass transfer because of its highly accessible 3D porosity. The results show that 3DOM BiVO4/TiO2 nanocomposites possess a highly prolonged lifetime and increased separation of visible light generated charges and extraordinarily high photocatalytic activity. Owing to the intimate contact between BiVO4 and large surface area 3DOM TiO2, the photogenerated high energy charges can be easily transferred from BiVO4 to the 3DOM TiO2 support. BiVO4 nanoparticles in the 3DOM TiO2 inverse opal structure act thus as a sensitizer to absorb visible light and to transfer efficiently high energy electrons to TiO2 to ensure long lifetime of the photogenerated charges and keep them well separated, owing to the direct band gap of BiVO4 of 2.4 eV, favourably positioned band edges, very low recombination rate of electron–hole pairs and stability when coupled with photocatalysts, explaining the extraordinarily high photocatalytic performance of 3DOM BiVO4/TiO2 nanocomposites. It is found that larger the amount of BiVO4 in the nanocomposite, longer the duration of photogenerated charge separation and higher the photocatalytic activity. This work can shed light on the development of novel visible light responsive nanomaterials for efficient solar energy utilisation by the intimate combination of an inorganic light sensitizing nanoparticle with an inverse opal structure with high diffusion efficiency and high accessible surface area.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 8.867
Times cited: 88
DOI: 10.1039/C5TA00783F
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“PDMS membranes containing ZIF-coated mesoporous silica spheres for efficient ethanol recovery via pervaporation”. Naik PV, Wee LH, Meledina M, Turner S, Li Y, Van Tendeloo G, Martens JA, Vankelecom IFJ, Journal of materials chemistry A : materials for energy and sustainability 4, 12790 (2016). http://doi.org/10.1039/C6TA04700A
Abstract: The design of functional micro- and mesostructured composite materials is significantly important for separation processes. Mesoporous silica is an attractive material for fast diffusion, while microporous zeolitic imidazolate frameworks (ZIFs) are beneficial for selective adsorption and diffusion. In this work, ZIF-71 and ZIF-8 nanocrystals were grown on the surface of mesoporous silica spheres (MSS) via the seeding and regrowth approach in order to obtain monodispersed MSS-ZIF-71 and MSS-ZIF-8 spheres with a particle size of 2-3 mm. These MSS-ZIF spheres were uniformly dispersed into a polydimethylsiloxane (PDMS) matrix to prepare mixed matrix membranes (MMMs). These MMMs were evaluated for the separation of ethanol from water via pervaporation. The pervaporation results reveal that the MSS-ZIF filled MMMs substantially improve the ethanol recovery in both aspects viz. flux and separation factor. These MMMs outperforms the unfilled PDMS membranes and the conventional carbon and zeolite filled MMMs. As expected, the mesoporous silica core allows very fast flow of the permeating compound, while the hydrophobic ZIF coating enhances the ethanol selectivity through its specific pore structure, hydrophobicity and surface chemistry. It can be seen that ZIF-8 mainly has a positive impact on the selectivity, while ZIF-71 enhances fluxes more significantly.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 8.867
Times cited: 26
DOI: 10.1039/C6TA04700A
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“Probing the electron beam-induced structural evolution of halide perovskite thin films by scanning transmission electron microscopy”. Zhou X-G, Yang C-Q, Sang X, Li W, Wang L, Yin Z-W, Han J-R, Li Y, Ke X, Hu Z-Y, Cheng Y-B, Van Tendeloo G, Journal Of Physical Chemistry C 125, 10786 (2021). http://doi.org/10.1021/ACS.JPCC.1C02156
Abstract: A deep understanding of the fine structure at the atomic scale of halide perovskite materials has been limited by their sensitivity to the electron beam that is widely used for structural characterization. The sensitivity of a gamma-CsPbIBr2 perovskite thin film under electron beam irradiation is revealed by scanning transmission electron microscopy (STEM) through a universal large-range electron dose measurement, which is based on discrete single-electron events in the STEM mode. Our research indicates that the gamma-CsPbIBr2 thin film undergoes structural changes with increasing electron overall dose (e(-).A(-2)) rather than dose rate (e(-).A(-2).s(-1)), which suggests that overall dose is the key operative parameter. The electron beam-induced structural evolution of gamma-CsPbIBr2 is monitored by fine control of the electron beam dose, together with the analysis of high-resolution (S)TEM, diffraction, and energy-dispersive X-ray spectroscopy. Our results show that the gamma-CsPbIBr2 phase first forms an intermediate phase [e.g., CsPb(1-x)(IBr)((3-y))] with a superstructure of ordered vacancies in the pristine unit cell, while a fraction of Pb2+ is reduced to Pb-0. As the electron dose increases, Pb nanoparticles precipitate, while the remaining framework forms the Cs2IBr phase, accompanied by some amorphization. This work provides guidelines to minimize electron beam irradiation artifacts for atomic-resolution imaging on CsPbIBr2 thin films.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 4.536
DOI: 10.1021/ACS.JPCC.1C02156
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“Quantitative FIB/SEM three-dimensional characterization of a unique Ni₄Ti₃, network in a porous Ni50.8Ti49.2 alloy undergoing a two-step martensitic transformation”. Cao S, Zeng CY, Li YY, Yao X, Ma X, Samaee V, Schryvers D, Zhang XP, Materials Characterization 169, 110595 (2020). http://doi.org/10.1016/J.MATCHAR.2020.110595
Abstract: The three-dimensional (3D) nanostructure of Ni4Ti3 precipitates in a porous Ni50.8Ti49.2 alloy has been re-constructed by “Slice-and-View” in a Focused Ion Beam/Scanning Electron Microscope (FIB/SEM). The 3D configuration of these precipitates forming a network structure in the B2 austenite matrix has been characterized via 3D visualization and quantitative analysis including volume fraction, skeleton, degree of anisotropy and local thickness. It is found that dense Ni4Ti3 precipitates occupy 54% of the volume in the B2 austenite matrix. Parallel Ni4Ti3 precipitates grow alongside the surface of a micro-pore, yielding an asymmetric structure, while nano voids do not seem to affect the growth of Ni4Ti3 precipitates. The small average local thickness of the precipitates around 60 nm allows their coherency with the matrix, and further induces the R-phase transformation in the matrix. On the other hand, the B2 matrix exhibits a winding and narrow structure with a skeleton of 18.20 mm and a thickness similar to the precipitates. This discontinuous matrix segmented by the Ni4Ti3 network and pores is responsible for the gradual transformation by stalling the martensite propagation.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 4.7
DOI: 10.1016/J.MATCHAR.2020.110595
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“Shape selective growth of single crystalline MnOOH multipods and 1D nanowires by a reductive hydrothermal method”. Mi Y, Zhang X, Yang Z, Li Y, Zhou S, Zhang H, Zhu W, He D, Wang J, Van Tendeloo G, Materials letters 61, 1781 (2007). http://doi.org/10.1016/j.matlet.2006.07.130
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.572
Times cited: 13
DOI: 10.1016/j.matlet.2006.07.130
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“A hidden single-stage martensitic transformation from B2 parent phase to B19 ' martensite phase in an aged Ni51Ti49 alloy”. Zeng CY, Cao S, Li YY, Zhao ZX, Yao XY, Ma X, Zhang XP, Materials letters 253, 99 (2019). http://doi.org/10.1016/J.MATLET.2019.06.055
Abstract: The aged Ni-rich NiTi shape memory alloys (SMAs) exhibit the multi-stage martensitic transformation (MMT), which has important influences on functional properties and practical applications of the NiTi SMAs. A hidden single-stage martensitic transformation from B2 parent phase to B19' martensite phase is found in an aged Ni51Ti49 alloy, which happens concurrently with a commonly observed two-stage martensitic transformation B2-R-B19' (R: martensite phase) and actually composes one stage of a multi-stage martensitic transformation (MMT) together with the two-stage one. B2-B19' martensitic transformation occurs in the NiTi matrix containing Ni4Ti3 precipitates with relatively large inter-particle space, while B2-R-B19' transformation takes place in the NiTi matrix with Ni4Ti3 precipitates having relatively small inter-particle space. (C) 2019 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.572
DOI: 10.1016/J.MATLET.2019.06.055
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“Identification of nano-width variants in a fully monoclinic martensitic Ni50Ti50 alloy by scanning electron microscope-based transmission Kikuchi diffraction and improved groupoid structure approach”. Zhao ZX, Ma X, Cao S, Li YY, Zeng CY, Wang DX, Yao X, Deng ZJ, Zhang XP, Materials Letters 281, 128624 (2020). http://doi.org/10.1016/J.MATLET.2020.128624
Abstract: Nano-width martensite plates in a fully martensitic Ni50Ti50 alloy are indexed successfully by using the off-axis transmission Kikuchi diffraction in scanning electron microscope (i.e., SEM-based TKD). The data obtained by SEM-TKD are effectively interpreted using an improved approach based on the framework of the theoretical groupoid structure method, where the equivalent variants transformed from the monoclinic variants are introduced to calculate all theoretical axis/angle pairs of rotation, and to formulate a complete list of source martensite to target martensite pairs. Consequently, B19' monoclinic martensite variants in NiTi alloys are identified unambiguously, by using numerical comparison between the experimental and theoretical rotation components, without the reference of retained parent phase. (C) 2020 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3
DOI: 10.1016/J.MATLET.2020.128624
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“Blue-edge slow photons promoting visible-light hydrogen production on gradient ternary 3DOM TiO 2 -Au-CdS photonic crystals”. Zhao H, Hu Z, Liu J, Li Y, Wu M, Van Tendeloo G, Su B-L, Nano energy 47, 266 (2018). http://doi.org/10.1016/j.nanoen.2018.02.052
Abstract: The slow photon effect, a structural effect of photonic crystal photocatalyst, is very efficient in the enhancement of photocatalytic reactions. However, slow photons in powdered photonic crystal photocatalyst have rarely been discussed because they are usually randomly oriented when the photocatalytic reaction happens in solution under constant stirring. In this work, for the first time we design a gradient ternary TiO2-Au-CdS photonic crystal based on three-dimensionally ordered macroporous (3DOM) TiO2 as skeleton, Au as electron transfer medium and CdS as active material for photocatalytic H2 production under visible-light. As a result, this gradient ternary photocatalyst is favorable to simultaneously enhance light absorption, extend the light responsive region and reduce the recombination rate of the charge carriers. In particular, we found that slow photons at blue-edge exhibit much higher photocatalytic activity than that at red-edge. The photonic crystal photocatalyst with a macropore size of 250 nm exhibits the highest visible-light H2 production rate of 3.50 mmolh⁻¹g⁻¹ due to the slow photon energy at the blue-edge to significantly enhance the incident photons utilization. This work verifies that slow photons at the blue-edge can largely enhance light harvesting and sheds a light on designing the powdered photonic crystal photocatalyst to promote the photocatalytic H2 production via slow photon effect.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 12.343
Times cited: 33
DOI: 10.1016/j.nanoen.2018.02.052
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“Phase selection enabled formation of abrupt axial heterojunctions in branched oxide nanowires”. Gao J, Lebedev OI, Turner S, Li YF, Lu YH, Feng YP, Boullay P, Prellier W, Van Tendeloo G, Wu T, Nano letters 12, 275 (2012). http://doi.org/10.1021/nl2035089
Abstract: Rational synthesis of nanowires via the vaporliquidsolid (VLS) mechanism with compositional and structural controls is vitally important for fabricating functional nanodevices from bottom up. Here, we show that branched indium tin oxide nanowires can be in situ seeded in vapor transport growth using tailored AuCu alloys as catalyst. Furthermore, we demonstrate that VLS synthesis gives unprecedented freedom to navigate the ternary InSnO phase diagram, and a rare and bulk-unstable cubic phase can be selectively stabilized in nanowires. The stabilized cubic fluorite phase possesses an unusual almost equimolar concentration of In and Sn, forming a defect-free epitaxial interface with the conventional bixbyite phase of tin-doped indium oxide that is the most employed transparent conducting oxide. This rational methodology of selecting phases and making abrupt axial heterojunctions in nanowires presents advantages over the conventional synthesis routes, promising novel composition-modulated nanomaterials.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 12.712
Times cited: 25
DOI: 10.1021/nl2035089
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“Tuning the optical, magnetic, and electrical properties of ReSe2 by nanoscale strain engineering”. Yang S, Wang C, Sahin H, Chen H, Li Y, Li SS, Suslu A, Peeters FM, Liu Q, Li J, Tongay S;, Nano letters 15, 1660 (2015). http://doi.org/10.1021/nl504276u
Abstract: Creating materials with ultimate control over their physical properties is vital for a wide range of applications. From a traditional materials design perspective, this task often requires precise control over the atomic composition and structure. However, owing to their mechanical properties, low-dimensional layered materials can actually withstand a significant amount of strain and thus sustain elastic deformations before fracture. This, in return, presents a unique technique for tuning their physical properties by strain engineering. Here, we find that local strain induced on ReSe2, a new member of the transition metal dichalcogenides family, greatly changes its magnetic, optical, and electrical properties. Local strain induced by generation of wrinkle (1) modulates the optical gap as evidenced by red-shifted photoluminescence peak, (2) enhances light emission, (3) induces magnetism, and (4) modulates the electrical properties. The results not only allow us to create materials with vastly different properties at the nanoscale, but also enable a wide range of applications based on 2D materials, including strain sensors, stretchable electrodes, flexible field-effect transistors, artificial-muscle actuators, solar cells, and other spintronic, electromechanical, piezoelectric, photonic devices.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 12.712
Times cited: 314
DOI: 10.1021/nl504276u
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“Spatial heterojunction in nanostructured TiO₂, and its cascade effect for efficient photocatalysis”. Lu Y, Liu X-L, He L, Zhang Y-X, Hu Z-Y, Tian G, Cheng X, Wu S-M, Li Y-Z, Yang X-H, Wang L-Y, Liu J-W, Janiak C, Chang G-G, Li W-H, Van Tendeloo G, Yang X-Y, Su B-L, Nano Letters 20, 3122 (2020). http://doi.org/10.1021/ACS.NANOLETT.9B05121
Abstract: A highly efficient photoenergy conversion is strongly dependent on the cumulative cascade efficiency of the photogenerated carriers. Spatial heterojunctions are critical to directed charge transfer and, thus, attractive but still a challenge. Here, a spatially ternary titanium-defected TiO2@carbon quantum dots@reduced graphene oxide (denoted as V-Ti@CQDs@rGO) in one system is shown to demonstrate a cascade effect of charges and significant performances regarding the photocurrent, the apparent quantum yield, and photocatalysis such as H-2 production from water splitting and CO2 reduction. A key aspect in the construction is the technologically irrational junction of Ti-vacancies and nanocarbons for the spatially inside-out heterojunction. The new “spatial heterojunctions” concept, characteristics, mechanism, and extension are proposed at an atomic- nanoscale to clarify the generation of rational heterojunctions as well as the cascade electron transfer.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 10.8
Times cited: 5
DOI: 10.1021/ACS.NANOLETT.9B05121
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“Engineering single crystalline Mn3O4 nano-octahedra with exposed highly active {011} facets for high performance lithium ion batteries”. Huang S-Z, Jin J, Cai Y, Li Y, Tan H-Y, Wang H-E, Van Tendeloo G, Su B-L, Nanoscale 6, 6819 (2014). http://doi.org/10.1039/c4nr01389a
Abstract: Well shaped single crystalline Mn3O4 nano-octahedra with exposed highly active {011} facets at different particle sizes have been synthesized and used as anode materials for lithium ion batteries. The electrochemical results show that the smallest sized Mn3O4 nano-octahedra show the best cycling performance with a high initial charge capacity of 907 mA h g−1 and a 50th charge capacity of 500 mA h g−1 at a current density of 50 mA g−1 and the best rate capability with a charge capacity of 350 mA h g−1 when cycled at 500 mA g−1. In particular, the nano-octahedra samples demonstrate a much better electrochemical performance in comparison with irregular shaped Mn3O4 nanoparticles. The best electrochemical properties of the smallest Mn3O4 nano-octahedra are ascribed to the lower charge transfer resistance due to the exposed highly active {011} facets, which can facilitate the conversion reaction of Mn3O4 and Li owing to the alternating Mn and O atom layers, resulting in easy formation and decomposition of the amorphous Li2O and the multi-electron reaction. On the other hand, the best electrochemical properties of the smallest Mn3O4 nano-octahedra can also be attributed to the smallest size resulting in the highest specific surface area, which provides maximum contact with the electrolyte and facilitates the rapid Li-ion diffusion at the electrode/electrolyte interface and fast lithium-ion transportation within the particles. The synergy of the exposed {011} facets and the smallest size (and/or the highest surface area) led to the best performance for the Mn3O4 nano-octahedra. Furthermore, HRTEM observations verify the oxidation of MnO to Mn3O4 during the charging process and confirm that the Mn3O4 octahedral structure can still be partly maintained after 50 dischargecharge cycles. The high Li-ion storage capacity and excellent cycling performance suggest that Mn3O4 nano-octahedra with exposed highly active {011} facets could be excellent anode materials for high-performance lithium-ion batteries.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 7.367
Times cited: 80
DOI: 10.1039/c4nr01389a
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“Interfacial co-existence of oxygen and titanium vacancies in nanostructured TiO₂, for enhancement of carrier transport”. Lu Y, Liu Y-X, He L, Wang L-Y, Liu X-L, Liu J-W, Li Y-Z, Tian G, Zhao H, Yang X-H, Liu J, Janiak C, Lenaerts S, Yang X-Y, Su B-L, Nanoscale 12, 8364 (2020). http://doi.org/10.1039/D0NR01180K
Abstract: The interfacial co-existence of oxygen and metal vacancies in metal oxide semiconductors and their highly efficient carrier transport have rarely been reported. This work reports on the co-existence of oxygen and titanium vacancies at the interface between TiO2 and rGO via a simple two-step calcination treatment. Experimental measurements show that the oxygen and titanium vacancies are formed under 550 degrees C/Ar and 350 degrees C/air calcination conditions, respectively. These oxygen and titanium vacancies significantly enhance the transport of interfacial carriers, and thus greatly improve the photocurrent performances, the apparent quantum yield, and photocatalysis such as photocatalytic H-2 production from water-splitting, photocatalytic CO2 reduction and photo-electrochemical anticorrosion of metals. A new “interfacial co-existence of oxygen and titanium vacancies” phenomenon, and its characteristics and mechanism are proposed at the atomic-/nanoscale to clarify the generation of oxygen and titanium vacancies as well as the interfacial carrier transport.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.7
Times cited: 4
DOI: 10.1039/D0NR01180K
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“Controllable synthesis of novel one-dimensional carbon nanomaterials on an alkali-element-modified Cu catalyst”. Tao XY, Zhang XB, Cheng J-P, Liu F, Li Y, Van Tendeloo G, Nanotechnology 17, 224 (2006). http://doi.org/10.1088/0957-4484/17/1/037
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.44
Times cited: 4
DOI: 10.1088/0957-4484/17/1/037
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“Fano resonances in bilayer phosphorene nanoring”. Zhang R, Wu Z, Li XJ, Li LL, Chen Q, Li Y-M, Peeters FM, Nanotechnology 29, 215202 (2018). http://doi.org/10.1088/1361-6528/AAB534
Abstract: Tunable transport properties and Fano resonances are predicted in a circular bilayer phosphorene nanoring. The conductance exhibits Fano resonances with varying incident energy and applied perpendicular magnetic field. These Fano resonance peaks can be accurately fitted with the well known Fano curves. When a magnetic field is applied to the nanoring, the conductance oscillates periodically with magnetic field which is reminiscent of the Aharonov-Bohm effect. Fano resonances are tightly related to the discrete states in the central nanoring, some of which are tunable by the magnetic field.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.44
Times cited: 4
DOI: 10.1088/1361-6528/AAB534
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“Edge stabilization in reduced-dimensional perovskites”. Quan LN, Ma D, Zhao Y, Voznyy O, Yuan H, Bladt E, Pan J, de Arquer FPG, Sabatini R, Piontkowski Z, Emwas A-H, Todorovic P, Quintero-Bermudez R, Walters G, Fan JZ, Liu M, Tan H, Saidaminov M I, Gao L, Li Y, Anjum DH, Wei N, Tang J, McCamant DW, Roeffaers MBJ, Bals S, Hofkens J, Bakr OM, Lu Z-H, Sargent EH, Nature Communications 11, 170 (2020). http://doi.org/10.1038/S41467-019-13944-2
Abstract: Reduced-dimensional perovskites are attractive light-emitting materials due to their efficient luminescence, color purity, tunable bandgap, and structural diversity. A major limitation in perovskite light-emitting diodes is their limited operational stability. Here we demonstrate that rapid photodegradation arises from edge-initiated photooxidation, wherein oxidative attack is powered by photogenerated and electrically-injected carriers that diffuse to the nanoplatelet edges and produce superoxide. We report an edge-stabilization strategy wherein phosphine oxides passivate unsaturated lead sites during perovskite crystallization. With this approach, we synthesize reduced-dimensional perovskites that exhibit 97 +/- 3% photoluminescence quantum yields and stabilities that exceed 300 h upon continuous illumination in an air ambient. We achieve green-emitting devices with a peak external quantum efficiency (EQE) of 14% at 1000 cd m(-2); their maximum luminance is 4.5 x 10(4) cd m(-2) (corresponding to an EQE of 5%); and, at 4000 cd m(-2), they achieve an operational half-lifetime of 3.5 h.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 16.6
Times cited: 147
DOI: 10.1038/S41467-019-13944-2
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“Gas permeation through graphdiyne-based nanoporous membranes”. Zhou Z, Tan Y, Yang Q, Bera A, Xiong Z, Yagmurcukardes M, Kim M, Zou Y, Wang G, Mishchenko A, Timokhin I, Wang C, Wang H, Yang C, Lu Y, Boya R, Liao H, Haigh S, Liu H, Peeters FM, Li Y, Geim AK, Hu S, Nature communications 13, 4031 (2022). http://doi.org/10.1038/S41467-022-31779-2
Abstract: Nanoporous membranes based on two dimensional materials are predicted to provide highly selective gas transport in combination with extreme permeance. Here we investigate membranes made from multilayer graphdiyne, a graphene-like crystal with a larger unit cell. Despite being nearly a hundred of nanometers thick, the membranes allow fast, Knudsen-type permeation of light gases such as helium and hydrogen whereas heavy noble gases like xenon exhibit strongly suppressed flows. Using isotope and cryogenic temperature measurements, the seemingly conflicting characteristics are explained by a high density of straight-through holes (direct porosity of similar to 0.1%), in which heavy atoms are adsorbed on the walls, partially blocking Knudsen flows. Our work offers important insights into intricate transport mechanisms playing a role at nanoscale.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 16.6
Times cited: 21
DOI: 10.1038/S41467-022-31779-2
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“Unprecedented and highly stable lithium storage capacity of (001) faceted nanosheet-constructed hierarchically porous TiO₂/rGO hybrid architecture for high-performance Li-ion batteries”. Yu W-B, Hu Z-Y, Jin J, Yi M, Yan M, Li Y, Wang H-E, Gao H-X, Mai L-Q, Hasan T, Xu B-X, Peng D-L, Van Tendeloo G, Su B-L, National Science Review 7, 1046 (2020). http://doi.org/10.1093/NSR/NWAA028
Abstract: Active crystal facets can generate special properties for various applications. Herein, we report a (001) faceted nanosheet-constructed hierarchically porous TiO2/rGO hybrid architecture with unprecedented and highly stable lithium storage performance. Density functional theory calculations show that the (001) faceted TiO2 nanosheets enable enhanced reaction kinetics by reinforcing their contact with the electrolyte and shortening the path length of Li+ diffusion and insertion-extraction. The reduced graphene oxide (rGO) nanosheets in this TiO2/rGO hybrid largely improve charge transport, while the porous hierarchy at different length scales favors continuous electrolyte permeation and accommodates volume change. This hierarchically porous TiO2/rGO hybrid anode material demonstrates an excellent reversible capacity of 250 mAh g(-1) at 1 C (1 C = 335 mA g(-1)) at a voltage window of 1.0-3.0 V. Even after 1000 cycles at 5 C and 500 cycles at 10 C, the anode retains exceptional and stable capacities of 176 and 160 mAh g(-1), respectively. Moreover, the formed Li2Ti2O4 nanodots facilitate reversed Li+ insertion-extraction during the cycling process. The above results indicate the best performance of TiO2-based materials as anodes for lithium-ion batteries reported in the literature.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 20.6
Times cited: 3
DOI: 10.1093/NSR/NWAA028
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“Single-cell yolk-shell nanoencapsulation for long-term viability with size-dependent permeability and molecular recognition”. Wang L, Li Y, Yang X-Y, Zhang B-B, Ninane N, Busscher HJ, Hu Z-Y, Delneuville C, Jiang N, Xie H, Van Tendeloo G, Hasan T, Su B-L, National Science Review 8 (2021). http://doi.org/10.1093/NSR/NWAA097
Abstract: Like nanomaterials, bacteria have been unknowingly used for centuries. They hold significant economic potential for fuel and medicinal compound production. Their full exploitation, however, is impeded by low biological activity and stability in industrial reactors. Though cellular encapsulation addresses these limitations, cell survival is usually compromised due to shell-to-cell contacts and low permeability. Here, we report ordered packing of silica nanocolloids with organized, uniform and tunable nanoporosities for single cyanobacterium nanoencapsulation using protamine as an electrostatic template. A space between the capsule shell and the cell is created by controlled internalization of protamine, resulting in a highly ordered porous shell-void-cell structure formation. These unique yolk-shell nano structures provide long-term cell viability with superior photosynthetic activities and resistance in harsh environments. In addition, engineering the colloidal packing allows tunable shell-pore diameter for size-dependent permeability and introduction of new functionalities for specific molecular recognition. Our strategy could significantly enhance the activity and stability of cyanobacteria for various nanobiotechnological applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 8.843
DOI: 10.1093/NSR/NWAA097
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“Ellipticalness index : a simple measure of the complexity of oval leaf shape”. Li Y, Quinn BK, Niinemets Ü, Schrader J, Gielis J, Liu M, Shi P, Pakistan journal of botany : An official publication of pakistan botanical society 54, 1 (2022). http://doi.org/10.30848/PJB2022-6(44)
Abstract: Plants have diverse leaf shapes that have evolved to adapt to the environments they have experienced over their evolutionary history. Leaf shape and leaf size can greatly influence the growth rate, competitive ability, and productivity of plants. However, researchers have long struggled to decide how to properly quantify the complexity of leaf shape. Prior studies recommended the leaf roundness index (RI = 4πA/P2) or dissection index (DI = ), where P is leaf perimeter and A is leaf area. However, these two indices merely measure the extent of the deviation of leaf shape from a circle, which is usually invalid as leaves are seldom circular. In this study, we proposed a simple measure, named the ellipticalness index (EI), for quantifying the complexity of leaf shape based on the hypothesis that the shape of any oval leaf can be regarded as a variation from a standard ellipse. 2220 leaves from nine species of Magnoliaceae were sampled to check the validity of the EI. We also tested the validity of the Montgomery equation (ME), which assumes a proportional relationship between leaf area and the product of leaf length and width, because the EI actually comes from the proportionality coefficient of the ME. We also compared the ME with five other models of leaf area. The ME was found to be the best model for calculating leaf area based on consideration of the trade-off between model fit vs. complexity, which strongly supported the robustness of the EI for describing oval leaf shape. The new index can account for both leaf shape and size, and we conclude that it is a promising method for quantifying and comparing oval leaf shapes across species in future studies.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 1.2
DOI: 10.30848/PJB2022-6(44)
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“3D interconnected hierarchically macro-mesoporous TiO2networks optimized by biomolecular self-assembly for high performance lithium ion batteries”. Ren X-N, Wu L, Jin J, Liu J, Hu Z-Y, Li Y, Hasan T, Yang X-Y, Van Tendeloo G, Su B-L, RSC advances 6, 26856 (2016). http://doi.org/10.1039/C6RA00332J
Abstract: Biomolecular self-assembly is an effective synthesis strategy for materials fabrication with unique structural complexity and properties. For the first time, we intergrate inner-particle mesoporosity in a three-dimensional (3D) interconnected macroporous TiO2 structure via the mediation of biomolecular self-assembly of the lipids and proteins from rape pollen coats and P123 to optimize the structure for high performance lithium storage. Benefitting from the hierarchically 3D interconnected macro-mesoporous structure with high surface area, small nanocrystallites and good electrolyte permeation, such unique porous structure demonstrates superior electrochemical performance, with high initial coulombic efficiency (94.4% at 1C) and a reversible discharge capacity of 161, 145, 127 and 97 mA h g-1 at 2, 5, 10 and 20C for 1000 cycles, with 79.3%, 89.9%, 90.1% and 87.4% capacity retention, respectively. Using SEM, TEM and HRTEM observations on the TiO2 materials before and after cycling, we verify that the inner-particle mesoporosity and the Li2Ti2O4 nanocrystallites formed during the cycling process in interconnected macroporous structure largely enhance the cycle life and rate performance. Our demonstration here offers opportunities towards developing and optimizing hierarchically porous structures for energy storage applications via biomolecular self-assembly.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.108
Times cited: 16
DOI: 10.1039/C6RA00332J
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“Probing the electrochemical behavior of {111} and {110} faceted hollow Cu2O microspheres for lithium storage”. Yu W-B, Hu Z-Y, Yi M, Huang S-Z, Chen D-S, Jin J, Li Y, Van Tendeloo G, Su B-L, RSC advances 6, 97129 (2016). http://doi.org/10.1039/C6RA21026K
Abstract: Transition metal oxides with exposed highly active facets have become of increasing interest as anode materials for lithium ion batteries, because more dangling atoms exposed at the active surface facilitate the reaction between the transition metal oxides and lithium. In this work, we probed the electrochemical behavior of hollow Cu2O microspheres with {111} and {110} active facets on the polyhedron surface as anodes for lithium storage. Compared to commercial Cu2O nanoparticles, hollow Cu2O microspheres with {111} and {110} active facets show a rising specific capacity at 30 cycles which then decreases after 110 cycles during the cycling process. Via advanced electron microscopy characterization, we reveal that this phenomenon can be attributed to the highly active {111} and {110} facets with dangling “Cu” atoms facilitating the conversion reaction of Cu2O and Li, where part of the Cu2O is oxidized to CuO during the charging process. However, as the reaction proceeds, more and more formed Cu nanoparticles cannot be converted to Cu2O or CuO. This leads to a decrease of the specific capacity. We believe that our study here sheds some light on the progress of the electrochemical behavior of transition metal oxides with respect to their increased specific capacity and the subsequent decrease via a conversion reaction mechanism. These results will be helpful to optimize the design of transition metal oxide micro/nanostructures for high performance lithium storage.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.108
Times cited: 5
DOI: 10.1039/C6RA21026K
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“Optimization of Automated Crystal Orientation Mapping in a TEM for Ni4Ti3 Precipitation in All-Round SMA”. Yao X, Amin-Ahmadi B, Li Y, Cao S, Ma X, Zhang X-P, Schryvers D, Shape memory and superelasticity 2, 286 (2016). http://doi.org/10.1007/s40830-016-0082-z
Abstract: Automated crystal orientation and phase mapping in TEM are applied to the quantification of Ni4Ti3 precipitates in Ni–Ti shape memory alloys which will be used for the implantation of artificial sphincters operating using the all-round shape memory effect. This paper focuses on the optimization process of the technique to obtain best values for all major parameters in the acquisition of electron diffraction patterns as well as template generation. With the obtained settings, vast statistical data on nano- and microstructures essential to the operation of these shape memory devices become available.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 2
DOI: 10.1007/s40830-016-0082-z
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“Well shaped Mn3O4 nano-octahedra with anomalous magnetic behavior and enhanced photodecomposition properties”. Li Y, Tan H, Yang X-Y, Goris B, Verbeeck J, Bals S, Colson P, Cloots R, Van Tendeloo G, Su B-L, Small 7, 475 (2011). http://doi.org/10.1002/smll.201001403
Abstract: Very uniform and well shaped Mn3O4 nano-octahedra are synthesized using a simple hydrothermal method under the help of polyethylene glycol (PEG200) as a reductant and shape-directing agent. The nano-octahedra formation mechanism is monitored. The shape and crystal orientation of the nanoparticles is reconstructed by scanning electron microscopy and electron tomography, which reveals that the nano-octahedra only selectively expose {101} facets at the external surfaces. The magnetic testing demonstrates that the Mn3O4 nano-octahedra exhibit anomalous magnetic properties: the Mn3O4 nano-octahedra around 150 nm show a similar Curie temperature and blocking temperature to Mn3O4 nanoparticles with 10 nm size because of the vertical axis of [001] plane and the exposed {101} facets. With these Mn3O4 nano-octahedra as a catalyst, the photodecomposition of rhodamine B is evaluated and it is found that the photodecomposition activity of Mn3O4 nano-octahedra is much superior to that of commercial Mn3O4 powders. The anomalous magnetic properties and high superior photodecomposition activity of well shaped Mn3O4 nano-octahedra should be related to the special shape of the nanoparticles and the abundantly exposed {101} facets at the external surfaces. Therefore, the shape preference can largely broaden the application of the Mn3O4 nano-octahedra.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 8.643
Times cited: 131
DOI: 10.1002/smll.201001403
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“Evidence that supertriangles exist in nature from the vertical projections of Koelreuteria paniculata fruit”. Li Y, Quinn BK, Gielis J, Li Y, Shi P, Symmetry 14, 23 (2022). http://doi.org/10.3390/SYM14010023
Abstract: Many natural radial symmetrical shapes (e.g., sea stars) follow the Gielis equation (GE) or its twin equation (TGE). A supertriangle (three triangles arranged around a central polygon) represents such a shape, but no study has tested whether natural shapes can be represented as/are supertriangles or whether the GE or TGE can describe their shape. We collected 100 pieces of Koelreuteria paniculata fruit, which have a supertriangular shape, extracted the boundary coordinates for their vertical projections, and then fitted them with the GE and TGE. The adjusted root mean square errors (RMSEadj) of the two equations were always less than 0.08, and >70% were less than 0.05. For 57/100 fruit projections, the GE had a lower RMSEadj than the TGE, although overall differences in the goodness of fit were non-significant. However, the TGE produces more symmetrical shapes than the GE as the two parameters controlling the extent of symmetry in it are approximately equal. This work demonstrates that natural supertriangles exist, validates the use of the GE and TGE to model their shapes, and suggests that different complex radially symmetrical shapes can be generated by the same equation, implying that different types of biological symmetry may result from the same biophysical mechanisms.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.7
DOI: 10.3390/SYM14010023
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