ORCID Profile
0000-0002-4246-0254
Current Organisation
University of Queensland
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Publisher: American Chemical Society (ACS)
Date: 10-01-2017
Abstract: Halide perovskites have recently been investigated for various solution-processed optoelectronic devices. The majority of studies have focused on using intrinsic halide perovskites, and the intentional incoporation of dopants has not been well explored. In this work, we discovered that small alkali ions, including lithium and sodium ions, could be electrochemically intercalated into a variety of halide and pseudohalide perovskites. The ion intercalation caused a lattice expansion of the perovskite crystals and resulted in an n-type doping of the perovskites. Such electrochemical doping improved the conductivity and changed the color of the perovskites, leading to an electrochromism with more than 40% reduction of transmittance in the 450-850 nm wavelength range. The doped perovskites exhibited improved electron injection efficiency into the pristine perovskite crystals, resulting in bright light-emitting diodes with a low turn-on voltage.
Publisher: World Scientific Pub Co Pte Lt
Date: 06-2015
DOI: 10.1142/S1793604715500381
Abstract: Graphene/hexagonal boron nitride (G/h-BN) heterostructure has attracted tremendous research efforts owing to its great potential for applications in nanoscale electronic devices. In such hybrid materials, tilt grain boundaries (GBs) between graphene and h-BN grains may have unique physical properties, which have not been well understood. Here we have conducted non-equilibrium molecular dynamics simulations to study the energetic and thermal properties of tilt GBs in G/h-BN heterostructures. The effect of misorientation angles of tilt GBs on both GB energy and interfacial thermal conductance are investigated.
Publisher: Springer Science and Business Media LLC
Date: 05-09-2020
Publisher: Elsevier BV
Date: 04-2015
Publisher: Trans Tech Publications, Ltd.
Date: 07-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/JNANOR.23.43
Abstract: Different types of defects can be introduced into graphene during material synthesis, and significantly influence the properties of graphene. In this work, we investigated the effects of structural defects, edge functionalisation and reconstruction on the fracture strength and morphology of graphene by molecular dynamics simulations. The minimum energy path analysis was conducted to investigate the formation of Stone-Wales defects. We also employed out-of-plane perturbation and energy minimization principle to study the possible morphology of graphene nanoribbons with edge-termination. Our numerical results show that the fracture strength of graphene is dependent on defects and environmental temperature. However, pre-existing defects may be healed, resulting in strength recovery. Edge functionalization can induce compressive stress and ripples in the edge areas of graphene nanoribbons. On the other hand, edge reconstruction contributed to the tensile stress and curved shape in the graphene nanoribbons.
Publisher: Elsevier BV
Date: 12-2022
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1NA00112D
Abstract: We investigate the electrochemical behavior of a square phase Janus MoSSe monolayer (1S-MoSSe) upon lithiation. Li adsorption triggers the local lattice distortion of 1S-MoSSe for avoiding structural instability.
Publisher: Springer Science and Business Media LLC
Date: 10-09-2021
DOI: 10.1038/S41467-021-25612-5
Abstract: The viability of lithium-sulfur batteries as an energy storage technology depends on unlocking long-term cycle stability. Most instability stems from the release and transport of polysulfides from the cathode, which causes mossy growth on the lithium anode, leading to continuous consumption of electrolyte. Therefore, development of a durable cathode with minimal polysulfide escape is critical. Here, we present a saccharide-based binder system that has a capacity for the regulation of polysulfides due to its reducing properties. Furthermore, the binder promotes the formation of viscoelastic filaments during casting which endows the sulfur cathode with a desirable web-like microstructure. Taken together this leads to 97% sulfur utilisation with a cycle life of 1000 cycles (9 months) and capacity retention (around 700 mAh g −1 after 1000 cycles). A pouch cell prototype with a specific energy of up to 206 Wh kg −1 is produced, demonstrating the promising potential for practical applications.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5RA27268H
Abstract: The mechanical properties of titanium dioxide (TiO 2 ) nanotubes are studied based on molecular dynamics simulations.
Publisher: Elsevier BV
Date: 05-2023
Publisher: Elsevier BV
Date: 08-2021
Publisher: American Chemical Society (ACS)
Date: 03-10-2016
Abstract: Solution-processed hybrid organic-inorganic lead halide perovskites are emerging as one of the most promising candidates for low-cost light-emitting diodes (LEDs). However, due to a small exciton binding energy, it is not yet possible to achieve an efficient electroluminescence within the blue wavelength region at room temperature, as is necessary for full-spectrum light sources. Here, we demonstrate efficient blue LEDs based on the colloidal, quantum-confined 2D perovskites, with precisely controlled stacking down to one-unit-cell thickness (n = 1). A variety of low-k organic host compounds are used to disperse the 2D perovskites, effectively creating a matrix of the dielectric quantum wells, which significantly boosts the exciton binding energy by the dielectric confinement effect. Through the Förster resonance energy transfer, the excitons down-convert and recombine radiatively in the 2D perovskites. We report room-temperature pure green (n = 7-10), sky blue (n = 5), pure blue (n = 3), and deep blue (n = 1) electroluminescence, with record-high external quantum efficiencies in the green-to-blue wavelength region.
Publisher: Wiley
Date: 22-12-2021
Abstract: The excellent optoelectronic properties and structural stability of inorganic cesium lead halide perovskites make them promising candidates for multiple types of optoelectronic devices. However, it remains a challenge to fabricate monocrystalline phase‐pure perovskite microstructures by facile low‐temperature solution‐based methods. Herein, a solution‐based method is demonstrated for controlling the crystallization of cesium halide perovskite microstructures. The structure of perovskite crystals is successfully tuned from non‐corner sharing Cs 4 PbBr 6 (0D) to corner‐sharing CsPbBr 3 (3D) to layered CsPb 2 Br 5 (2D) by controlling water (H 2 O) to dimethylsulfoxide (DMSO) ratios. Molecular dynamics simulations and thermodynamic analysis indicate that the relative stability of Pb 2+ and Br − ions in solution is the key factor in determining which crystals form at different H 2 O/DMSO ratios, with Cs + simply incorporated as needed. The phase‐pure 0D crystals exhibit a high photoluminescence quantum yield of 41%, whilst the 2D crystals have an onset of absorption at 350 nm. Furthermore, the as‐synthesized, highly uniform 3D perovskite single crystals are coupled with nanofabricated interdigitated electrodes to show excellent X‐ray detection, with a high sensitivity of 8000 μC Gy air −1 cm −2 obtained under a 0.5V external bias. This is comparable to many commercial X‐ray detectors (Si, α‐Se) and several times higher than other reported inorganic perovskite materials (CsPbBr 3 quantum dots, Cs 2 AgBiBr 6 ).
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.JMBBM.2014.04.002
Abstract: Bone is characterized with an optimized combination of high stiffness and toughness. The understanding of bone nanomechanics is critical to the development of new artificial biological materials with unique properties. In this work, the mechanical characteristics of the interfaces between osteopontin (OPN, a noncollagenous protein in extrafibrillar protein matrix) and hydroxyapatite (HA, a mineral nanoplatelet in mineralized collagen fibrils) were investigated using molecular dynamics method. We found that the interfacial mechanical behavior is governed by the electrostatic attraction between acidic amino acid residues in OPN and calcium in HA. Higher energy dissipation is associated with the OPN peptides with a higher number of acidic amino acid residues. When loading in the interface direction, new bonds between some acidic residues and HA surface are formed, resulting in a stick-slip type motion of OPN peptide on the HA surface and high interfacial energy dissipation. The formation of new bonds during loading is considered to be a key mechanism responsible for high fracture resistance observed in bone and other biological materials.
Publisher: MDPI AG
Date: 25-05-2023
DOI: 10.3390/NANO13111732
Abstract: A core–shell nanowire heterostructure is an important building block for nanowire-based optoelectronic devices. In this paper, the shape and composition evolution induced by adatom diffusion is investigated by constructing a growth model for alloy core–shell nanowire heterostructures, taking diffusion, adsorption, desorption and incorporation of adatoms into consideration. With moving boundaries accounting for sidewall growth, the transient diffusion equations are numerically solved by the finite element method. The adatom diffusions introduce the position-dependent and time-dependent adatom concentrations of components A and B. The newly grown alloy nanowire shell depends on the incorporation rates, resulting in both shape and composition evolution during growth. The results show that the morphology of nanowire shell strongly depends on the flux impingement angle. With the increase in this impingement angle, the position of the largest shell thickness on sidewall moves down to the bottom of nanowire and meanwhile, the contact angle between shell and substrate increases to an obtuse angle. Coupled with the shell shapes, the composition profiles are shown as non-uniform along both the nanowire and the shell growth directions, which can be attributed to the adatom diffusion of components A and B. The impacts of parameters on the shape and composition evolution are systematically investigated, including diffusion length, adatom lifetime and corresponding ratios between components. This kinetic model is expected to interpret the contribution of adatom diffusion in growing alloy group-IV and group III-V core–shell nanowire heterostructures.
Publisher: American Chemical Society (ACS)
Date: 28-07-2017
Publisher: Elsevier BV
Date: 12-2021
Publisher: Springer Science and Business Media LLC
Date: 30-06-2017
DOI: 10.1038/NCOMMS16086
Abstract: Perovskite CH 3 NH 3 PbI 3 exhibits outstanding photovoltaic performances, but the understanding of the atomic motions remains inadequate even though they take a fundamental role in transport properties. Here, we present a complete atomic dynamic picture consisting of molecular jumping rotational modes and phonons, which is established by carrying out high-resolution time-of-flight quasi-elastic and inelastic neutron scattering measurements in a wide energy window ranging from 0.0036 to 54 meV on a large single crystal s le, respectively. The ultrafast orientational disorder of molecular dipoles, activated at ∼165 K, acts as an additional scattering source for optical phonons as well as for charge carriers. It is revealed that acoustic phonons dominate the thermal transport, rather than optical phonons due to sub-picosecond lifetimes. These microscopic insights provide a solid standing point, on which perovskite solar cells can be understood more accurately and their performances are perhaps further optimized.
Publisher: American Chemical Society (ACS)
Date: 20-12-2021
Publisher: Springer Science and Business Media LLC
Date: 10-12-2015
DOI: 10.1038/SREP18122
Abstract: The elastic modulus of carbyne, a one-dimensional carbon chain, was recently predicted to be much higher than graphene. Inspired by this discovery and the fundamental correlation between elastic modulus and thermal conductivity, we investigate the intrinsic thermal transport in two carbon allotropes: carbyne and cumulene. Using molecular dynamics simulations, we discover that thermal conductivities of carbyne and cumulene at the quantum-corrected room temperature can exceed 54 and 148 kW/m/K, respectively, much higher than that for graphene. Such conductivity is attributed to high phonon energies and group velocities, as well as reduced scattering from non-overlapped acoustic and optical phonon modes. The prolonged spectral acoustic phonon lifetime of 30–110 ps and mean free path of 0.5–2.5 μm exceed those for graphene and allow ballistic phonon transport along micron-length carbon chains. Tensile extensions can enhance the thermal conductivity of carbyne due to the increased phonon density of states in the acoustic modes and the increased phonon lifetime from phonon bandgap opening. These findings provide fundamental insights into phonon transport and band structure engineering through tensile deformation in low-dimensional materials and will inspire studies on carbyne, cumulene and boron nitride chains for their practical deployments in nano-devices.
Publisher: Wiley
Date: 25-05-2016
Publisher: Elsevier BV
Date: 10-2022
Publisher: Elsevier BV
Date: 03-2012
Publisher: Wiley
Date: 03-07-2017
Abstract: Hybrid organic-inorganic metal halide perovskites possess exceptional structural tunability, with three- (3D), two- (2D), one- (1D), and zero-dimensional (0D) structures on the molecular level all possible. While remarkable progress has been realized in perovskite research in recent years, the focus has been mainly on 3D and 2D structures, with 1D and 0D structures significantly underexplored. The synthesis and characterization of a series of low-dimensional organic tin bromide perovskites with 1D and 0D structures is reported. Using the same organic and inorganic components, but at different ratios and reaction conditions, both 1D (C
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1NR06832F
Abstract: It remains challenging to achieve both strength and toughness in network materials via crosslinking. The hybridly double-crosslinked carbon nanotube networks designed here nicely achieve cooperative energy dissipation with minimal structural damage.
Publisher: American Chemical Society (ACS)
Date: 25-04-2022
Publisher: Elsevier BV
Date: 02-2023
Publisher: American Chemical Society (ACS)
Date: 19-01-2023
Publisher: Scientific Research Publishing, Inc.
Date: 2012
Publisher: Elsevier BV
Date: 02-2022
Publisher: Wiley
Date: 09-08-2020
Publisher: Wiley
Date: 11-11-2019
Publisher: Elsevier BV
Date: 07-2020
Publisher: Springer Science and Business Media LLC
Date: 25-01-2021
DOI: 10.1038/S41467-020-20691-2
Abstract: Accurately identifying the local structural heterogeneity of complex, disordered amorphous materials such as amorphous silicon is crucial for accelerating technology development. However, short-range atomic ordering quantification and nanoscale spatial resolution over a large area on a-Si have remained major challenges and practically unexplored. We resolve phonon vibrational modes of a-Si at a lateral resolution of nm by tip-enhanced Raman spectroscopy. To project the high dimensional TERS imaging to a two-dimensional manifold space and categorize amorphous silicon structure, we developed a multiresolution manifold learning algorithm. It allows for quantifying average Si-Si distortion angle and the strain free energy at nanoscale without a human-specified physical threshold. The multiresolution feature of the multiresolution manifold learning allows for distilling local defects of ultra-low abundance ( 0.3%), presenting a new Raman mode at finer resolution grids. This work promises a general paradigm of resolving nanoscale structural heterogeneity and updating domain knowledge for highly disordered materials.
Publisher: American Chemical Society (ACS)
Date: 28-11-2016
Publisher: American Association for the Advancement of Science (AAAS)
Date: 17-02-2023
Abstract: To harvest and reuse low-temperature waste heat, we propose and realize an emergent concept—barocaloric thermal batteries based on the large inverse barocaloric effect of ammonium thiocyanate (NH 4 SCN). Thermal charging is initialized upon pressurization through an order-to-disorder phase transition, and the discharging of 43 J g −1 takes place at depressurization, which is 11 times more than the input mechanical energy. The thermodynamic equilibrium nature of the pressure-restrained heat-carrying phase guarantees stable long-duration storage. The barocaloric thermal batteries reinforced by their solid microscopic mechanism are expected to substantially advance the ability to take advantage of waste heat.
Publisher: Wiley
Date: 11-2021
Publisher: AIP Publishing
Date: 08-10-2015
DOI: 10.1063/1.4932213
Abstract: Titanium dioxide (TiO2) nanotube arrays are attracting increasing attention for use in solar cells, lithium-ion batteries, and biomedical implants. To take full advantage of their unique physical properties, such arrays need to maintain adequate mechanical integrity in applications. However, the mechanical performance of TiO2 nanotube arrays is not well understood. In this work, we investigate the deformation and failure of TiO2 nanotube arrays using the nanoindentation technique. We found that the load–displacement response of the arrays strongly depends on the indentation depth and indenter shape. Substrate-independent elastic modulus and hardness can be obtained when the indentation depth is less than 2.5% of the array height. The deformation mechanisms of TiO2 nanotube arrays by Berkovich and conical indenters are closely associated with the densification of TiO2 nanotubes under compression. A theoretical model for deformation of the arrays under a large-radius conical indenter is also proposed.
Publisher: American Scientific Publishers
Date: 07-2014
Publisher: AIP Publishing
Date: 05-08-2014
DOI: 10.1063/1.4892089
Abstract: The effect of graphene oxide (GO) on the mechanical properties and the curing reaction of Diglycidyl Ether of Bisphenol A/F and Triethylenetetramine epoxy system was investigated. GO was prepared by oxidation of graphite flakes and characterized by spectroscopic and microscopic techniques. Epoxy nanocomposites were fabricated with different GO loading by solution mixing technique. It was found that incorporation of small amount of GO into the epoxy matrix significantly enhanced the mechanical properties of the epoxy. In particular, model I fracture toughness was increased by nearly 50% with the addition of 0.1 wt. % GO to epoxy. The toughening mechanism was understood by fractography analysis of the tested s les. The more irregular, coarse, and multi-plane fracture surfaces of the epoxy/GO nanocomposites were observed. This implies that the two-dimensional GO sheets effectively disturbed and deflected the crack propagation. At 0.5 wt. % GO, elastic modulus was ∼35% greater than neat epoxy. Differential scanning calorimetry (DSC) results showed that GO addition moderately affect the glass transition temperature (Tg) of epoxy. The maximum decrease of Tg by ∼7 °C was shown for the nanocomposite with 0.5 wt. % GO. DSC results further revealed that GO significantly hindered the cure reaction in the epoxy system.
Publisher: MDPI AG
Date: 19-12-2021
DOI: 10.3390/NANO11123442
Abstract: Based on density functional theory, we theoretically investigate the electronic structures of free-standing armchair Janus MoSSe nanoribbons (A-MoSSeNR) with width up to 25.5 nm. The equilibrium structures of nanoribbons with spontaneous curling are obtained by energy minimization in molecular dynamics (MD). The curvature is 0.178 nm−1 regardless of nanoribbon width. Both finite element method and analytical solution based on continuum theory provide qualitatively consistent results for the curling behavior, reflecting that relaxation of intrinsic strain induced by the atomic asymmetry acts as the driving force. The non-edge bandgap of curled A-MoSSeNR reduces faster with the increase of width compared with planar nanoribbons. It can be observed that the real-space wave function at the non-edge VBM is localized in the central region of the curled nanoribbon. When the curvature is larger than 1.0 nm−1, both edge bandgap and non-edge bandgap shrink with the further increase of curvature. Moreover, we explore the spontaneous curling and consequent sewing process of nanoribbon to form nanotube (Z-MoSSeNT) by MD simulations. The spontaneously formed Z-MoSSeNT with 5.6 nm radius possesses the lowest energy. When radius is smaller than 0.9 nm, the bandgap of Z-MoSSeNT drops rapidly as the radius decreases. We expect the theoretical results can help build the foundation for novel nanoscale devices based on Janus TMD nanoribbons.
Publisher: Informa UK Limited
Date: 03-04-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TA05356B
Abstract: This work explores the molecular-level mechanisms of thermal instability in pristine and defective crystals of the prototypical hybrid perovskite MAPbI 3 .
Publisher: American Chemical Society (ACS)
Date: 28-09-2022
Abstract: A solid electrolyte interphase (SEI) with robust mechanical property and high ionic conductivity is imperative for high-performance lithium metal batteries since it can efficiently impede the growth of notorious lithium dendrites. However, it is difficult to form such a SEI directly from an electrolyte. In this work, a crowding dilutant modified ionic liquid electrolyte (M-ILE) has been developed for this purpose. Simulations and experiments indicate that the 1,2-difluorobenzene (1,2-dfBen) dilutant not only creates a crowded electrolyte environment to promote the interaction of Li
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1NA00198A
Abstract: Based on digital metamaterials designed by topology optimization, not only precise manipulation of mode order, but also reciprocal unidirectional transmission and mode ision multiplexing are achieved with ultra-small device footprint.
Publisher: Elsevier BV
Date: 09-2022
Publisher: American Chemical Society (ACS)
Date: 09-12-2016
Abstract: Although organic-inorganic hybrid perovskites have been extensively investigated for promising applications in energy-related devices, their mechanical properties, which restrict their practical deployment as flexible and wearable devices, have been largely unexplored at the atomistic level. Toward this level of understanding, we predict the elastic constant matrix and various elastic properties of CH
Publisher: Elsevier BV
Date: 02-2013
Publisher: Wiley
Date: 30-03-2022
Abstract: The application of ultrathin 2D perovskites in near‐infrared and visible‐range optoelectronics is limited owing to their inherent wide bandgaps, large excitonic binding energies, and low optical absorption at higher wavelengths. Here, it is shown that by tailoring interfacial band alignments via conjugation with low‐dimensional materials like monolayer transition metal dichalcogenides (TMD), the functionalities of 2D perovskites can be extended to erse, visible‐range photophysical applications. Based on the choice of in idual constituents in the 2D perovskite/TMD heterostructures, first principles calculations demonstrate widely tunable type‐II bandgaps, carrier effective masses, and band offsets to enable an effective separation of photogenerated excitons for enhanced photodetection and photovoltaic applications. In addition, the possibilities of achieving a type‐I band alignment for recombination‐based light emitters as well as a type‐III configuration for tunneling devices are shown. Further, the effect of strain on the electronic properties of the heterostructures are evaluated to show a significant strain tolerance, making them prospective candidates in flexible photosensors.
Publisher: American Chemical Society (ACS)
Date: 13-12-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TA01883J
Abstract: An asymmetric gel polymer electrolyte is designed for regulating ions and suppressing Li dendrite growth in high-performance Li metal batteries.
Publisher: Wiley
Date: 11-08-2021
Abstract: Azobenzene‐doped glassy polyimides (azo‐polyimides) offer some of the most efficient optomechanical power densities to date rivaling electrostrictive polymers. Despite such potential attributes, the optomechanical efficiency remains low in comparison to other smart materials. Using high‐fidelity coarse‐grained molecular dynamics simulations, the authors reconcile both experimental and theoretical challenges to understand the limiting factors for the optomechanical conversion in photostrictive polymers. Interestingly, the ideal optomechanical efficiency of 10–24% for a single‐chain azo‐imide monomer predicted here is equal to or a little higher than experimental reports, suggesting experimental design space. The time‐dependent optomechanical efficiency of bulk azo‐polyimide is quantified, for the first time, to be strongly correlated with the initial free volumes, a measure of polymer conformational freedom. This trend is elaborated by conformational order parameters and viscoelastic relaxation moduli. Resembling the role of porosity in azobenzene‐contained metal/covalent organic frameworks to enhance the photo‐switching efficiency, a larger conformational freedom enables times increase in optomechanical efficiency comparing to existing experiments. This is primarily due to facilitated viscoelastic relaxation after photo‐switching which alleviates residual stresses quickly and reduces heat dissipation. These findings suggest opportunities to improve the optomechanical performance through targeted strategies, such as porosity control and thermal annealing.
Publisher: American Chemical Society (ACS)
Date: 03-05-2022
DOI: 10.1021/ACS.JPCLETT.2C00360
Abstract: Owing to their excellent optoelectronic properties, quasi-2D perovskites with self-assembled multiple quantum well (MQW) structures have shown great potential in light-emitting diode (LED) applications. Understanding the correlation between the bulky cation, quantum well assembly, and optoelectronic properties of a quasi-2D perovskite is important. Here, we demonstrate that the dipole moment of the bulky cation can be one of the fundamental factors that controls the distribution and crystallinity of different quantum wells. We find that the bulky cation with a moderate dipole moment leads to moderately distributed well-width MQWs, resulting in a superior device efficiency due to the simultaneous achievement of favorable optical and electronic properties. The peak external quantum efficiency and the maximum luminance of the ch ion device are 10.8% and 19082 cd m
Publisher: MDPI AG
Date: 07-03-2023
DOI: 10.3390/NANO13060968
Abstract: Compared with traditional alloys, high-entropy alloys have better mechanical properties and corrosion resistance. However, their mechanical properties and microstructural evolution behavior are unclear due to their complex composition. Machine learning has powerful data processing and analysis capabilities, that provides technical advantages for in-depth study of the mechanical properties of high-entropy alloys. Thus, we combined machine learning and molecular dynamics to predict the mechanical properties of FeNiCrCoCu high-entropy alloys. The optimal multiple linear regression machine learning algorithm predicts that the optimal composition is Fe33Ni32Cr11Co11Cu13 high-entropy alloy, with a tensile strength of 28.25 GPa. Furthermore, molecular dynamics is used to verify the predicted mechanical properties of high-entropy alloys, and it is found that the error between the tensile strength predicted by machine learning and the tensile strength obtained by molecular dynamics simulation is within 0.5%. Moreover, the tensile-compression asymmetry of Fe33Ni32Cr11Co11Cu13 high-entropy alloy increased with the increase of temperature and Cu content and the decrease of Fe content. This is due to the increase in stress caused by twinning during compression and the decrease in stress due to dislocation slip during stretching. Interestingly, high-entropy alloy coatings reduce the tensile-compression asymmetry of nickel this is attributed to the reduced influence of dislocations and twinning at the interface between the high-entropy alloy and the nickel matrix.
Publisher: American Chemical Society (ACS)
Date: 24-04-2020
Publisher: AIP Publishing
Date: 28-03-2014
DOI: 10.1063/1.4870170
Abstract: Graphene has been increasingly used as nano sized fillers to create a broad range of nanocomposites with exceptional properties. The interfaces between fillers and matrix play a critical role in dictating the overall performance of a composite. However, the load transfer mechanism along graphene-polymer interface has not been well understood. In this study, we conducted molecular dynamics simulations to investigate the influence of surface functionalization and layer length on the interfacial load transfer in graphene-polymer nanocomposites. The simulation results show that oxygen-functionalized graphene leads to larger interfacial shear force than hydrogen-functionalized and pristine ones during pull-out process. The increase of oxygen coverage and layer length enhances interfacial shear force. Further increase of oxygen coverage to about 7% leads to a saturated interfacial shear force. A model was also established to demonstrate that the mechanism of interfacial load transfer consists of two contributing parts, including the formation of new surface and relative sliding along the interface. These results are believed to be useful in development of new graphene-based nanocomposites with better interfacial properties.
Publisher: SAGE Publications
Date: 02-2014
DOI: 10.1177/096739111402200217
Abstract: The piezoelectric composite material could engender stress concentration resulting from small cracks during layers easily, as the cracks growth will lead to the failure of the whole structure. In this paper, a finite element model for piezoelectric composite materials by ABAQUS including interlayer crack was established, and the J integral and crack tip stress of different types PZT patches were calculated by using the equivalent integral method. Then, the J integral for adhesive layers with different thickness, elastic modulus considering and not considering piezoelectricity was investigated. The results show that the J integral of mode I, II reduces with thicker adhesive layer and lower elastic modules, and the J integral of mode II decreases more sharply than that of mode I.
Publisher: AIP Publishing
Date: 23-06-2016
DOI: 10.1063/1.4954683
Abstract: A better understanding of lithium-silicon alloying mechanisms and associated mechanical behavior is essential for the design of Si-based electrodes for Li-ion batteries. Unfortunately, the relationship between the dynamic mechanical response and microstructure evolution during lithiation and delithiation has not been well understood. We use molecular dynamic simulations to investigate lithiated amorphous silicon with a focus to the evolution of its microstructure, phase composition, and stress generation. The results show that the formation of LixSi alloy phase is via different mechanisms, depending on Li concentration. In these alloy phases, the increase in Li concentration results in reduction of modulus of elasticity and fracture strength but increase in ductility in tension. For a LixSi system with uniform Li distribution, volume change induced stress is well below the fracture strength in tension.
Publisher: American Chemical Society (ACS)
Date: 02-12-2019
DOI: 10.1021/ACS.JPCLETT.9B03023
Abstract: Magnesium halide salts are an exciting prospect as stable and high-performance electrolytes for rechargeable Mg batteries (RMBs). By nature of their complex equilibria, these salts exist in solution as a variety of electroactive species (EAS) in equilibrium with counterions such as AlCl
Publisher: MDPI AG
Date: 29-10-2019
DOI: 10.3390/NANO9111535
Abstract: Ceramics have been widely used in many fields because of their distinctive properties, however, brittle fracture usually limits their application. To solve this problem, nanoglass ceramics were developed. In this article, we numerically investigated the mechanical properties of nanoglass aluminium nitride (ng-AlN) with different glassy grain sizes under tension using molecular dynamics simulations. It was found that ng-AlN exhibits super ductility and tends to deform uniformly without the formation of voids as the glassy grain size decreases to about 1 nm, which was attributed to a large number of uniformly distributed shear transformation zones (STZs). We further investigated the effects of temperature and strain rate on ng-AlNd = 1 nm, which showed that temperature insignificantly influences the elastic modulus, while the dependence of the ultimate strength on temperature follows the T2/3 scaling law. Meanwhile, the ultimate strength of ng-AlNd = 1 nm is positively correlated with the strain rate, following a power function relationship.
Publisher: American Chemical Society (ACS)
Date: 13-01-2021
Publisher: American Chemical Society (ACS)
Date: 11-12-2019
Abstract: Magnesium (Mg) metal has been widely explored as an anode material for Mg-ion batteries (MIBs) owing to its large specific capacity and dendrite-free operation. However, critical challenges, such as the formation of passivation layers during battery operation and anode-electrolyte-cathode incompatibilities, limit the practical application of Mg-metal anodes for MIBs. Motivated by the promise of group XIV elements (namely, Si, Ge, and Sn) as anodes for lithium- and sodium-ion batteries, here, we conduct systematic first-principles calculations to explore the thermodynamics and kinetics of group XIV anodes for MIBs and to identify the atomistic mechanisms of the electrochemical insertion reactions of Mg ions. We confirm the formation of amorphous Mg
Publisher: Wiley
Date: 04-2022
Publisher: Springer Science and Business Media LLC
Date: 12-09-2022
Publisher: American Association for the Advancement of Science (AAAS)
Date: 12-2017
Abstract: The first low-dimensional semiconductor nanocrystal system that increases the photoluminescence quantum yield in aggregates.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9TA10422D
Abstract: Light harvesting capacity of caesium silver bismuth bromide double perovskite need to be enhanced to render this non-toxic and thermodynamically stable material suitable for photovoltaic applications, for ex le as a top layer in tandem solar cells.
Publisher: American Chemical Society (ACS)
Date: 07-11-2017
Publisher: American Chemical Society (ACS)
Date: 22-10-2019
Publisher: Wiley
Date: 17-01-2023
Abstract: Lithium‐sulfur batteries are famous for high energy density but prevented by shuttling effect and sluggish electrochemical conversion kinetics due to the high energy barriers of Li + transport across the electrode/electrolyte interface. Herein, the Li + ‐solvents dissociation kinetics is catalyzed and stimulated by designing a carbon bridged metal‐organic framework (MOF@CC), aimed at realizing increased bare Li + transport for the rapid conversion kinetics of sulfur species. Theoretical simulations and spectroscopic results demonstrate that the bridged MOF@CC well grants a special transport channel for accelerating Li + benefited from aggregated anion/cation clusters. Moreover, the CN bridge between ‐NH 2 ligand in MOF and carbon shell enhances electron exchange, and thus promotes polysulfide catalytic efficiency and hinder polysulfide aggregation and accumulation. With the MOF@CC‐modified separators, the assembled Li/S batteries deliver a reversible capability of 1063 mAh g ‐1 at 0.5 C, a capacity retention of 88% after 100 cycles, and a high‐rate performance of 765 mAh g −1 at 5 C. Moreover, the large areal pouch cell with 100 µm Li foil and lean electrolyte is capable of stabilizing 855 mAh g −1 after 70 cycles. These results well demonstrate the efficiency of catalyzing desolvation for fast Li+ transport kinetics and the conversion of polysulfides.
Publisher: American Chemical Society (ACS)
Date: 29-08-2022
Publisher: American Chemical Society (ACS)
Date: 13-08-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7RA01399J
Abstract: A fundamental understanding of mechanical behavior of a Li–Si system is necessary to address the poor mechanical integrity of amorphous silicon (a-Si) electrodes, in order to utilize their enormous capacity in Li-ion batteries.
Publisher: Elsevier BV
Date: 07-2013
Publisher: Elsevier BV
Date: 12-2017
Publisher: Elsevier BV
Date: 09-2020
No related grants have been discovered for Mingchao Wang.