Parent Bulk Materials Research Articles

Big Data in a Nano World: A Review on Computational, Data-Driven Design of Nanomaterials Structures, Properties, and Synthesis.

The recent rise of computational, data-driven research has significant potential to accelerate materials discovery. Automated workflows and materials databases are being rapidly developed, contributing to high-throughput data of bulk materials that are growing in quantity and complexity, allowing for correlation between structural-chemical features and functional properties. In contrast, computational data-driven approaches are still relatively rare for nanomaterials discovery due to the rapid scaling of computational cost for finite systems. However, the distinct behaviors at the nanoscale as compared to the parent bulk materials and the vast tunability space with respect to dimensionality and morphology motivate the development of data sets for nanometric materials. In this review, we discuss the recent progress in data-driven research in two aspects: functional materials design and guided synthesis, including commonly used metrics and approaches for designing materials properties and predicting synthesis routes. More importantly, we discuss the distinct behaviors of materials as a result of nanosizing and the implications for data-driven research. Finally, we share our perspectives on future directions for extending the current data-driven research into the nano realm.

Easily exfoliable monolayer of GdTe[formula omitted]: ab initio study

A recently synthesized material GdTe3 has shown very interesting properties like superconductivity and high carrier mobility in its bulk and flake form. Here, we have shown the formation of a monolayer of GdTe3 from its bulk parent material by means of exfoliation. We have also studied magnetic ground state and electronic properties of bulk and two-dimensional (2D) GdTe3, using ab initio calculations. We find both of them to have the same anti-ferromagnetic spin arrangement in their ground state. Our calculations further reveal that both bulk and 2D-GdTe3 are metallic, mainly because of the electronic contribution arising from the Te-atoms. The magnetic ground state does not change on the inclusion of the Hubbard-U parameter, calculated self-consistently to have a value of 5.7 eV for the Gd-f electrons. The spin–orbit coupling (SOC) calculations in 2D-GdTe3, for both U = 0 and 5.7 eV, show that the system prefers an in-plane anti-ferromagnetic ordering and has an easy magnetization axis along the crystallographic a-direction.

Hybrid Spinel Iron Oxide Nanoarchitecture Combining Crystalline and Amorphous Parent Material

When preparing nanostructured magnetic materials, the presence of an amorphous component is often considered a weakness of the synthesis method and a waste of material. This stems because the amorphous fraction is often pictured as a “dead” magnetic component, showing little to no contribution to the magnetic properties, for example, saturation magnetization. For this reason, additional steps are employed after the main synthesis process to reduce or isolate and remove the amorphous phase from the “optimal” crystalline product. Here, we propose a hybrid-structured nanoarchitecture that combines crystalline cobalt ferrite and the amorphous parent material. The latter contributes partially to the total magnetic moment but exhibits a magnetic anisotropy much larger than the crystalline bulk parent material. With the information obtained from an in-depth structural and magnetic characterization, a micromagnetic model is created, allowing identifying the contribution of each component elucidating the active role of the amorphous phase. The extremely low cost, minimal complexity, and high yield of the synthesis process make this hybrid design of large interest for technological applications.

Revealing Nanomechanical Domains and Their Transient Behavior in Mixed‐Halide Perovskite Films

AbstractHalide perovskites are a versatile class of semiconductors employed for high performance emerging optoelectronic devices, including flexoelectric systems, yet the influence of their ionic nature on their mechanical behavior is still to be understood. Here, a combination of atomic‐force, optical, and compositional X‐ray microscopy techniques is employed to shed light on the mechanical properties of halide perovskite films at the nanoscale. Mechanical domains within and between morphological grains, enclosed by mechanical boundaries of higher Young's Modulus (YM) than the bulk parent material, are revealed. These mechanical boundaries are associated with the presence of bromide‐rich clusters as visualized by nano‐X‐ray fluorescence mapping. Stiffer regions are specifically selectively modified upon light soaking the sample, resulting in an overall homogenization of the mechanical properties toward the bulk YM. This behavior is attributed to light‐induced ion migration processes that homogenize the local chemical distribution, which is accompanied by photobrightening of the photoluminescence within the same region. This work highlights critical links between mechanical, chemical, and optoelectronic characteristics in this family of perovskites, and demonstrates the potential of combinational imaging studies to understand and design halide perovskite films for emerging applications such as photoflexoelectricity.

Interactions of metal-based nanoparticles (MBNPs) and metal-oxide nanoparticles (MONPs) with crop plants: a critical review of research progress and prospects

Over the past decade, the production and applications of metal-based and metal-oxide nanoparticles (MBNPs and MONPs, respectively) have increased significantly due to their enhanced physicochemical properties and biological activities when compared with their bulk parent materials. Once MBNPs and MONPs enter agricultural soil via direct or indirect pathways, they can interact with crop plants and thus pose a threat to both animal and human health through food chain pathways. Although many review articles on engineered nanoparticles have been published, few have focused on the interactions of MBNPs and MONPs with crop plants and their current applications. Therefore, we reviewed the sources and behaviors of MBNPs and MONPs in agricultural soil, physiological and biochemical effects of MBNPs and MONPs on plants, uptake, translocation of MBNPs and MONPs in crop plants, factors affecting the interaction between MBNPs and MONPs and plants, and the applications of MBNPs and MONPs. Lastly, we propose where the future research priorities should be focused to provide a better understanding of MBNPs and MONPs. This review will help to promote scientific research regarding MBNPs and MONPs and to understand the risks and benefits of their association with plants and will contribute to the advancement of nanotechnology.

Co-Solvent Exfoliation of Hexagonal Boron Nitride: Effect of Raw Bulk Boron Nitride Size and Co-Solvent Composition.

Exfoliation of two-dimensional boron nitride nanosheets (BNNSs) from parent bulk material has been receiving intensive attention because of its fascinating physical properties. Liquid exfoliation is a simple, scalable approach to produce single-layer or few-layer BNNS. In this paper, water/propanol co-solvent exfoliation of bulk boron nitride under the assistance of sonication was investigated in detail. Special attention was paid on the effect of raw bulk boron nitride size and co-solvent composition. The results show that sonication of small-size hexagonal boron nitride tends to generate large nanosheets, due to a predominant solvent wedge effect. In addition, it is found that the composition of water/propanol co-solvent has an important effect on exfoliation efficiency. Interestingly, although two isomers of 1-propanol (NPA) and 2-propanol (IPA) have the same molecular weight and similar surface tension, their aqueous solutions allow the formation of boron nitride nanosheets dispersion with markedly different concentrations. It is proposed that due to their spatial configuration difference, NPA with its longer molecular chain and fewer hydrophobic methyl group tends to form dynamic water-NPA clusters with larger size than water-IPA clusters. The hydrodynamic radius of the co-solvent “clusters” was calculated to be 0.72 nm for water/NPA system and 0.44 nm for water/IPA system at their maximum, respectively. Their size changes, represented by two curves, indicate a strong “cluster size” effect on exfoliation efficiency. Our work provides an insight into co-solvent exfoliation of hexagonal boron nitride and emphasizes the importance of co-solvent cluster size in exfoliation efficiency.

Exfoliation and characterization of a two-dimensional serpentine-based material

We report on an experimental investigation of serpentine, an abundant phyllosilicate, as an alternative source of two-dimensional (2D) nanomaterials. We show, through scanning probe microscopy (SPM) measurements, that natural serpentine mineral can be mechanically exfoliated down to few-layer flakes, where monolayers can be easily resolved. The parent serpentine bulk material was initially characterized via conventional techniques like XRD, XPS, FTIR and Raman spectroscopies and the results show that it is predominantly constituted by the antigorite mineral. From ab initio calculations using density functional theory, we also determine the geometry and electronic structure of antigorite, the observed structural form of serpentine. Additionally, we further characterized electrical and mechanical properties of the obtained 2D material flakes using SPM and broadband synchrotron infrared nanospectroscopy. Wavelength tuning of the serpentine vibrational resonances, assigned to in- and out-of-plane molecular vibrations, are observed and compared with the FTIR characterization of the parent bulk material. They show that there is no degradation of serpentine’s structural properties during its mechanical exfoliation down to nanometer-thin sheets. Therefore, our results introduce the serpentine mineral as an attractive low-cost candidate in 2D materials applications.

Theoretical investigating of graphene/antimonene heterostructure as a promising high cycle capability anodes for fast-charging lithium ion batteries

Abstract Alloy Sb as an anode material for Li ion batteries (LIBs) suffers from severe volume expansion and structural breakdown during lithiation process, leading to a abrupt drop of battery cycle performance. The density functional theory is used to explore the adsorption and diffusion of Li atom in the two dimensional graphene/β-antimonene (G/Sb) heterostructure. Our calculation results reveal that the G/Sb heterostructure possesses excellent thermodynamic and dynamic stability with the 0.06 eV band gap, which is much smaller than that of monolayer Sb (1.24 eV) and can insure fast electron transport in the electrode during lithiation/delithiation process. The calculated smaller Li diffusion energy barrier and volume expansion, together with the larger Li diffusion coefficient at 300 K explore greater charge/discharge performance for the G/Sb heterostructure than the corresponding parent bulk, monolayer, and bilayer materials. This is mainly because the monolayer β-Sb within the G/Sb heterostructure can render larger strain compared with that of the pristine β-Sb. We also evaluate the performance of the G/Sb heterostructure as the anode of LIBs by charge analysis and density of states. These results provide conclusive evidence to explore that the G/Sb heterostructure should be a promising candidate anode for flexible and wearable LIBs.

Effects of soot by-product from the synthesis of engineered metallofullerene nanomaterials on terrestrial invertebrates.

The synthesis of carbon-based nanomaterials is often inefficient, generating large amounts of soot with metals as waste by-product. Currently, there are no specific regulations for disposal of engineered nanomaterials or the waste by-products resulting from their synthesis, so it is presumed that by-products are disposed of in the same way as the parent (bulk) materials. We studied the terrestrial toxicity of soot from gadolinium metallofullerene nanomanufacturing on earthworms (Eisenia fetida) and isopods (Porcellio scaber). The metallofullerene soot consisted of carbon particle agglomerates in the nanometer and submicrometer ranges (1-100 and 101-999 nm, respectively), with metals used during nanomanufacturing detectable on the particles. Despite high metal concentrations (>100 000 mg/kg) in the soot, only a relatively small amount of metals leached out of a spiked field soil, suggesting only moderate mobility. Seven- and 14-d exposures in field soil demonstrated that the soot was only toxic to earthworms at high concentrations (>10 000 mg/kg); however, earthworms avoided spiked soils at lower concentrations (as low as 500 mg/kg) and at lower soil pH. The presence of soot in food and soil did not cause isopod avoidance. These data demonstrate that metallofullerene soot from nanomanufacturing may only be toxic to earthworms at high concentrations representative of improper disposal or accidental spills. However, our results indicate that terrestrial invertebrates may avoid soils contaminated with soot at sublethal concentrations. Environ Toxicol Chem 2018;9999:1-12. Published 2018 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work, and as such, is in the public domain in the United States of America.

Investigating phase transition temperatures of size separated gadolinium silicide magnetic nanoparticles

Gadolinium silicide (Gd5Si4) nanoparticles (NPs) exhibit different properties compared to their parent bulk materials due to finite size, shape, and surface effects. NPs were prepared by high energy ball-milling of the as-cast Gd5Si4 ingot and size separated into eight fractions using time sensitive sedimentation in an applied dc magnetic field with average particle sizes ranging from 700 nm to 82 nm. The largest Gd5Si4 NPs order ferromagnetically at 316 K. A second anomaly observed at 110 K can be ascribed to a Gd5Si3 impurity. As the particle sizes decrease, the volume fraction of Gd5Si3 phase increases at the expense of the Gd5Si4 phase, and the ferromagnetic transition temperature of Gd5Si4 is reduced from 316 K to 310 K, while the ordering of the minor phase is independent of the particle size, remaining at 110 K.

Microstructure and mechanical properties of surface and subsurface layers in broached and shot-peened Inconel-718 gas turbine disc fir-trees

Metallurgical and mechanical characterization of surface and subsurface regions in broached and shot-peened fir-trees in an industrial gas turbine disc made of Inconel-718 were carried out. High resolution scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectrometry (EDS), electron backscatter diffraction (EBSD), X-ray diffraction, optical microscopy, and microhardness instruments were employed for qualitative and quantitative assessment of alterations at surface and subsurface levels. Five specific locations along the broached and shot-peened path were selected and thoroughly examined. Original metallography methods were developed to clearly and reliably reveal microstructure constituents. Special emphasis was placed on the generated defects in view of the manufacturer's quality indices, formation mechanisms of defects, and their potential impact on the service capability of the disc. Also, advanced analysis of the EBSD data allowed assessment of the deformed layer thickness as well as the misorientation angle and grain size variations from the broached and shot-peened surface towards the bulk parent material (PM). Furthermore, through successive material removal by electropolishing, measurement of residual stresses as a function of depth from the surface was performed by the sin2Ψ method. The obtained results are analyzed in terms of impact of the processing conditions on the evolution of microstructure, microhardness, and residual stresses. The findings are also related to the geometrical location in the disc.

Understanding energy transfer with luminescent gold nanoclusters: a promising new transduction modality for biorelated applications.

Ultrasmall noble metal and especially gold nanoclusters (AuNCs, ≤2 nm diameter in size) display a range of unique quantum confined and photophysical properties which are far different from their larger-sized nanoparticle counterparts or that of the bulk parent material. Amongst these properties, the photoluminescence of gold AuNCs has stimulated much interest for biological applications due to a combination of their small size, high photostability and range of emissions depending on size and surface stabilizing ligands, including near-IR emission. The dearth of robust Förster resonance energy transfer (FRET) donors and acceptors available to populate the latter spectral range is also driving strong interest in applying AuNCs for similar utility and especially for biosensing. However, the exact mechanism of how AuNCs engage in this type of energy transfer (ET) is still not defined and accumulating evidence indicates that it is not by a classical Förster process although, interestingly, many of the same characteristics and photophysical requirements seem to be present and even many-times required. Here, we summarize the state of the art in AuNC ET studies with a special emphasis on relevance to biological utility ranging from diagnostics to distance measurements along with describing the different ET mechanisms that have been ascribed with their use. Due to its corresponding importance in this discussion, we provide a brief overview of how these materials are synthesized, the current understanding of how their photoluminescence originates, and some related information on silver nanocluster (AgNC) ET along with related processes such as chemically-induced ET. A perspective and outlook on how this area will develop in the future is also provided.

Computer Modelling Studies of Lithium Transport in Nanoporous and Bulk Beta-MnO2

Nanostructured manganese dioxides (MnO2) are among the promising materials for high-capacity lithium-ion batteries [1], lithium air batteries [2] and supercapacitors [3], that can be used in electric vehicles and other consumer electronics. Simulated amorphisation recrystallisation method has been successfully used to nucleate and crystallise bulk [4] and nanoporous β-MnO2 [5]. In the current study we demonstrate that nanostructuring of MnO2 results in the exposure of a variety of surfaces to be exposed at the (internal) pores because of the high curvature of the material; the low energy MnO2(101) surface does not dominate the morphology. This nanostructuring facilitates a wide variation of entrance sites into the 1x1 tunnels in contrast to the parent bulk material. In particular, the activation energy associated with Li intercalation/deintercallation into the (101) surface of the bulk material is calculated to be 0.6eV. On the other hand, for the mesoporous material we calculate the activation energy for Li transport and deintercallation to be 0.4eV. 1] B.X. Li, G.X. Rong, Y. Xie, L.F. Huang and C.Q. Feng, Inorg. Chem. 2006, 45, 6404. [2] A. Débart, A.J. Paterson, J. Bao and P.G. Bruce, Angew. Chem., Int. Ed. 2008, 47, 4521. [3] W. Wei, X. Cui, W. Chen and D.G. Ivey, Chem. Soc. Rev. 2011, 40, 1697 [4] T.X.T. Sayle, C.R.A. Catlow, R.R. Maphanga, P.E. Ngoepe and D.C. Sayle, J. Crystal Growth, 294,118-129, 2006. [5] T.X.T. Sayle, R.R. Maphanga, P.E. Ngoepe and D.C. Sayle, J. American Chem. Soc., 131, 6161-6173, 2009.

Dissimilar friction stir welding of aluminum alloys reinforced with carbon nanotubes

This chapter is devoted to studying the possibility of incorporating carbon nanotubes (CNTs) as reinforcing fillers in dissimilar metal matrices joints produced by friction stir welding (FSW), as well as the impact of this incorporation on the microstructural and mechanical properties of these joints. Carbon nanotubes are extensively used as a reinforcing material in nanocomposites, due to their high stiffness and strength. FSW is a solid-state welding process of joining aluminum and other metallic alloys and has been employed in the aerospace, rail, automotive, and marine industries. Recently, friction stir processing (FSP), a derivative method of FSW, has been employed as an alternative for the production of metal matrix composites (MMCs). In this work, the process parameters were optimized in order to achieve nondefective welds, with and without the addition of CNTs. Two main cases were studied: (1) FSP was optimized by changing the tool rotational and travel speed as well as the number and direction of FSW passes, and (2) a Taguchi design scheme was adopted to further investigate the FSP in relevance to three factors (number, direction of passes, and tool rotational speed). Mechanical behavior was studied, and the local mechanical properties of the produced MMCs were compared with their bulk counterparts and parent materials. More specifically, the measured mechanical properties in the micro- and nanoscale (namely hardness and elastic modulus) are correlated with the microstructure and the presence of fillers.

Energy-momentum mapping ofd-derived Au(111) states in a thin film

The quantum well states of a film can be used to sample the electronic structure of the parent bulk material and determine its band parameters. We highlight the benefits of two-dimensional film band mapping, with respect to complex bulk analysis, in an angle-resolved photoemission spectroscopy study of the $5d$ states of Au(111). Discrete $5d$-derived quantum well states of various orbital characters form in Au(111) films and span the width of the corresponding bulk bands. For sufficiently thick films, the dispersion of these states samples the bulk band edges, as confirmed by first-principles calculations, thus providing the positions of the critical points of bulk Au in agreement with previously determined values. In turn, this analysis identifies several $d$-like surface states and resonances with large spin splittings that originate from the strong spin-orbit coupling of the Au $5d$ atomic levels.

Dissimilar Friction Stir Welding Between 5083 and 6082 Al Alloys Reinforced With TiC Nanoparticles

Dissimilar friction stir welding between aluminum alloys thick plates reinforced with TiC nanoparticles was conducted. The defect-free welds are characterized by good mechanical mixing between the joined materials as well as by good nanoparticle distribution and further grain refinement in comparison with the unreinforced weld. The local mechanical behavior of the produced metal matrix composites was studied and compared with their bulk counterparts and parent materials. Specifically, the measured mechanical properties in microscale and nanoscale (namely hardness and elastic modulus) are correlated with microstructure and the presence of fillers. The hardness, elastic modulus, ultimate tensile strength, percentage of elongation, and yield values increase with the presence of TiC nanoparticles.

Computational Modelling Study on Electrochemical Activity of Nanoporous and Bulk Beta MnO2

Nanostructured manganese dioxides (MnO2) are among the promising materials for high-capacity lithium-ion batteries [1], lithium air batteries [2] and supercapacitors [3], that can be used in electric vehicles and other consumer electronics. They further have several advantages owing to their high specific energy capacity, low fabrication cost, abundance of the materials in the earth, and environmentally friendly nature [4]. Various experimental methods have been employed for the synthesis of MnO2 with various nano-architectures such as the spheres, sheets, porous, wires, rods [5,6] etc. Simulated amorphisation recrystallisation method has been successfully used to nucleate and crystallise bulk and nanoporous β-MnO2 [7]. In the current study molecular dynamics simulation reveals that the reason nanoporous β-MnO2 is electrochemically active, in contrast to the parent bulk material, is because strain imposed upon nanoporous β-MnO2 during lithium intercalation does not influence the structure or dimensions of the 1D tunnels in which the lithium ions intercalate and reside. Conversely, the parent bulk material suffers structural collapse of the 1D tunnels under strain. [1] B.X. Li, G.X. Rong, Y. Xie, L.F. Huang and C.Q. Feng, Inorg. Chem. 2006, 45, 6404. [2] A. Débart, A.J. Paterson, J. Bao and P.G. Bruce, Angew. Chem., Int. Ed. 2008, 47, 4521. [3] W. Wei, X. Cui, W. Chen and D.G. Ivey, Chem. Soc. Rev. 2011, 40, 1697. [4] S. Devaraj and N. Munichandraiah, J. Phys. Chem. C 2008, 112, 4406. [5] J.H. Cheng, G.A. Shao, H.J. Yu and J.J. Xu, J. Alloys Compd. 2010, 505, 163. [6] X. Wang and Y. Li, Chem. Eur. J. 2003, 9, 300. [7] P.E.Ngoepe, R.R. Maphanga and D.C. Sayle, (2013), “Towards the Nanoscale”, Chapter 9 in Computational Approaches to Energy Materials, pp 261-290, edited by C.R.A. Catlow, A. Sokol and A. Welsch, John Wiley and Sons Ltd.

Room temperature multiferroism in CaTcO3 by interface engineering

We carry out systematic studies of the structural instabilities of the new perovskite family ATcO3 (A=Ca, Sr, Ba) by first-principles calculations. The orthorhombic ground state of CaTcO3 and SrTcO3 are found to be closely related to structural distortions due to the zone boundary phonon instabilities. We also identify a weak ferroelectric instability in CaTcO3, which is however suppressed at the ground state due to the large antiferrodistortive mode. We show that the ferroelectricity in CaTcO3 can be induced in the CaTcO3/BaTcO3 superlattices. Two types of interface mechanisms are involved, one is realized by the mismatch of the antipolar modes between two parent bulk materials and the other is the suppression of antiferrodistortive mode at interface. The Néel temperature of CaTcO3/BaTcO3 superlattices is found to be ∼816K, indicating that CaTcO3 can be engineered into a new room temperature multiferroic material.

One-dimensional half-metallic interfaces of two-dimensional honeycomb insulators

We study zigzag interfaces between insulating compounds that are isostructural to graphene, specifically II-VI, III-V and IV-IV two-dimensional (2D) honeycomb insulators. We show that these one-dimensional interfaces are polar, with a net density of excess charge that can be simply determined by using the ideal (integer) formal valence charges, regardless of the predominant covalent character of the bonding in these materials. We justify this finding on fundamental physical grounds, by analyzing the topology of the formal polarization lattice in the parent bulk materials. First principles calculations elucidate an electronic compensation mechanism not dissimilar to oxide interfaces, which is triggered by a Zener-like charge transfer between interfaces of opposite polarity. In particular, we predict the emergence of one dimensional electron and hole gases (1DEG), which in some cases are ferromagnetic half-metallic.

Heat Capacity Studies of Surface Water Confined on Cassiterite (SnO2) Nanoparticles

Heat capacities have been measured on a series of 2, 6, 11, and 20 nm SnO2 nanoparticles with varying amounts of surface water as well as on a bulk parent material, in the temperature range from 2 to 300 K. By subtracting the heat capacity values for 2 nm SnO2 samples with different water contents, we calculated the heat capacity contribution of the anhydrous lattice and found that the lattice heat capacity of the nanoparticle is the same as that of the bulk material within experimental error. This is further confirmation that, for several systems, once one accounts properly for the heat capacity of adsorbed water there is no measurable excess lattice heat capacity related to particle size. Using this result, we have calculated the heat capacities of confined water on the surfaces of the various SnO2 nanoparticles and found the water behavior to be generally similar to that of bulk ice, although with some differences in detail. The heat capacity of confined water on these same SnO2 nanoparticles calculate...