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Yuan Y, Patel RK, Banik S, Reta TB, Bisht RS, Fong DD, Sankaranarayanan SKRS, Ramanathan S. Proton Conducting Neuromorphic Materials and Devices. Chem Rev 2024; 124:9733-9784. [PMID: 39038231 DOI: 10.1021/acs.chemrev.4c00071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Neuromorphic computing and artificial intelligence hardware generally aims to emulate features found in biological neural circuit components and to enable the development of energy-efficient machines. In the biological brain, ionic currents and temporal concentration gradients control information flow and storage. It is therefore of interest to examine materials and devices for neuromorphic computing wherein ionic and electronic currents can propagate. Protons being mobile under an external electric field offers a compelling avenue for facilitating biological functionalities in artificial synapses and neurons. In this review, we first highlight the interesting biological analog of protons as neurotransmitters in various animals. We then discuss the experimental approaches and mechanisms of proton doping in various classes of inorganic and organic proton-conducting materials for the advancement of neuromorphic architectures. Since hydrogen is among the lightest of elements, characterization in a solid matrix requires advanced techniques. We review powerful synchrotron-based spectroscopic techniques for characterizing hydrogen doping in various materials as well as complementary scattering techniques to detect hydrogen. First-principles calculations are then discussed as they help provide an understanding of proton migration and electronic structure modification. Outstanding scientific challenges to further our understanding of proton doping and its use in emerging neuromorphic electronics are pointed out.
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Affiliation(s)
- Yifan Yuan
- Department of Electrical & Computer Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Ranjan Kumar Patel
- Department of Electrical & Computer Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Suvo Banik
- Department of Mechanical and Industrial Engineering, University of Illinois, Chicago, Illinois 60607, United States
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Tadesse Billo Reta
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Ravindra Singh Bisht
- Department of Electrical & Computer Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Dillon D Fong
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Subramanian K R S Sankaranarayanan
- Department of Mechanical and Industrial Engineering, University of Illinois, Chicago, Illinois 60607, United States
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Shriram Ramanathan
- Department of Electrical & Computer Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
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Plass KE, Krebs JK, Morford JL, Schaak RE, Stapleton JJ, van Duin ACT. Nanomaterials Research at a Primarily Undergraduate Institution: Transforming Nanorods, Undergraduate Research Communities, and Infrastructure. ACS NANOSCIENCE AU 2024; 4:223-234. [PMID: 39184836 PMCID: PMC11342341 DOI: 10.1021/acsnanoscienceau.4c00005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 04/10/2024] [Accepted: 04/11/2024] [Indexed: 08/27/2024]
Abstract
Undergraduate research transforms student's conceptions of themselves as scientists and encourages participation and retention in science, technology, engineering, and mathematics (STEM) fields. Many barriers exist to carrying out scientifically impactful undergraduate research in nanomaterials at primarily undergraduate institutions (PUIs). Here, we share several practices and design principles that demonstrate pathways to overcome these barriers. Design of modular research projects with low entry barriers is essential. Postsynthetic transformation of nanoparticles is a field that enables such design and has been used successfully to advance nanoscience research while being achievable within undergraduate laboratories. Relatively large, inclusive research communities can be supported through the creation of opportunities with peer- and near-peer mentoring. We also share emerging strategies for enabling routine undergraduate access to transmission electron microscopy, which is one of the most mainstream characterization techniques in nanoscience yet is frequently absent from the infrastructure at undergraduate-focused institutions.
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Affiliation(s)
- Katherine E. Plass
- Department
of Chemistry, Franklin & Marshall College, Lancaster, Pennsylvania 17604, United States
| | - J. Kenneth Krebs
- Department
of Physics, Franklin & Marshall College, Lancaster, Pennsylvania 17604, United States
| | - Jennifer L. Morford
- Department
of Chemistry, Franklin & Marshall College, Lancaster, Pennsylvania 17604, United States
| | - Raymond E. Schaak
- Department
of Chemistry, Department of Chemical Engineering, Materials Research
Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Joshua J. Stapleton
- Materials
Research Institute, The Pennsylvania State
University, University Park, Pennsylvania 16802, United States
| | - Adri C. T. van Duin
- Department
of Mechanical and Nuclear Engineering, Pennsylvania
State University, University Park, Pennsylvania 16802, United States
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3
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Zhou R, Bao L, Bu W, Zhou F. Adaptive accelerated reactive molecular dynamics driven by parallel collective variables overcoming dimensionality explosion. J Chem Phys 2024; 161:054103. [PMID: 39087533 DOI: 10.1063/5.0222514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2024] [Accepted: 07/14/2024] [Indexed: 08/02/2024] Open
Abstract
ReaxFF reactive molecular dynamics has significantly advanced the exploration of chemical reaction mechanisms in complex systems. However, it faces several challenges: (1) the prevalent use of excessively high temperatures (>2000 K), (2) a time scale considerably shorter than the experimental timeframes (nanoseconds vs seconds), and (3) the constraining impact of dimensionality growth due to collective variables on the expansiveness of research systems. To overcome these issues, we introduced Parallel Collective Variable-Driven Adaptive Accelerated Reaction Molecular Dynamics (PCVR), which integrates metadynamics with ReaxFF. This method incorporates bond distortion based on each bond type for customized Collective Variable (CV) parameterization, facilitating independent parallel acceleration. Simultaneously, the sampling was confined to fixed cutoff ranges for distinct bond distortions, effectively overcoming the challenge of the CV dimensionality explosion. This extension enhances the applicability of ReaxFF to non-strongly coupled systems with numerous reaction energy barriers and mitigates the system size limitations. Using accelerated reactive molecular dynamics, the oxidation of ester-based oil was simulated with 31 808 atoms at 500 K for 64 s. This achieved 61% efficiency compared to the original ReaxFF and was ∼37 times faster than previous methods. Unlike ReaxFF's high-temperature constraints, PCVR accurately reveals the pivotal role of oxygen in ester oxidation at industrial temperatures, producing polymers consistent with the sludge formation observed in ester degradation experiments. This method promises to advance reactive molecular dynamics by enabling simulations at lower temperatures, extending to second-level timescales, and accommodating systems with millions of atoms.
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Affiliation(s)
- Rui Zhou
- Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry, and College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Luyao Bao
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
- Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai, Yantai 264006, China
| | - Weifeng Bu
- Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry, and College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Feng Zhou
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
- Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai, Yantai 264006, China
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4
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Sredenschek AJ, Sanchez DE, Wang J, Lei Y, Sinnott SB, Terrones M. Heterostructures coupling ultrathin metal carbides and chalcogenides. NATURE MATERIALS 2024; 23:460-469. [PMID: 38561520 DOI: 10.1038/s41563-024-01827-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 01/22/2024] [Indexed: 04/04/2024]
Abstract
Non-layered transition metal carbides (TMCs) and layered transition metal dichalcogenides (TMDs) are two well-studied material families that have individually received considerable attention over the past century. In recent years, with the shift towards two-dimensional materials and heterostructures, a field has emerged that is focused on the structure and properties of TMC/TMD heterostructures, which through chemical conversion exhibit diverse types of heterostructure configuration that host coupled 2D-3D interfaces, giving rise to exotic properties. In this Review, we highlight experimental and computational efforts to understand the routes to fabricate TMC/TMD heterostructures. Furthermore, we showcase how controlling these heterostructures can lead to emergent electronic transport, optical properties and improved catalytic properties.
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Affiliation(s)
- Alexander J Sredenschek
- Department of Physics, The Pennsylvania State University, University Park, PA, USA
- Center for 2D and Layered Materials, The Pennsylvania State University, University Park, PA, USA
| | - David Emanuel Sanchez
- Center for 2D and Layered Materials, The Pennsylvania State University, University Park, PA, USA
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Jiayang Wang
- Center for 2D and Layered Materials, The Pennsylvania State University, University Park, PA, USA
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Yu Lei
- Institute of Materials Research & Center of Double Helix & Guangdong Provincial Key Laboratory of Thermal Management Engineering and Materials, Tsinghua Shenzhen International Graduate School, Shenzhen, China
| | - Susan B Sinnott
- Center for 2D and Layered Materials, The Pennsylvania State University, University Park, PA, USA.
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA.
| | - Mauricio Terrones
- Department of Physics, The Pennsylvania State University, University Park, PA, USA.
- Center for 2D and Layered Materials, The Pennsylvania State University, University Park, PA, USA.
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA.
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Rai AK, Shah AA, Kumar J, Chattaraj S, Dar AB, Patbhaje U, Shrivastava M. MoS 2 Field-Effect Transistor Performance Enhancement by Contact Doping and Defect Passivation via Fluorine Ions and Its Cyclic Field-Assisted Activation. ACS NANO 2024; 18:6215-6228. [PMID: 38345911 DOI: 10.1021/acsnano.3c09428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
MoS2-based field-effect transistors (FETs) and, in general, transition metal dichalcogenide channels are fundamentally limited by high contact resistance (RC) and intrinsic defects, which results in low drive current and lower carrier mobilities, respectively. This work addresses these issues using a technique based on CF4 plasma treatment in the contacts and further cyclic field-assisted drift and activation of the fluorine ions (F-), which get introduced into the contact region during the CF4 plasma treatment. The F- ions are activated using cyclic pulses applied across the source-drain (S/D) contacts, which leads to their migration to the contact edges via the channel. Further, using ab initio molecular dynamics and density functional theory simulations, these F- ions are found to bond at sulfur (S) vacancies, resulting in their passivation and n-type doping in the channel and near the S/D contacts. An increase in doping results in the narrowing of the Schottky barrier width and a reduction in RC by ∼90%. Additionally, the passivation of S vacancies in the channel enhances the mobility of the FET by ∼150%. The CF4 plasma treatment in contacts and further cyclic field-assisted activation of F- ions resulted in an ON-current (ION) improvement by ∼90% and ∼480% for exfoliated and CVD-grown MoS2, respectively. Moreover, this improvement in ION has been achieved without any deterioration in the ION/IOFF, which was found to be >7-8 orders.
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Affiliation(s)
- Anand Kumar Rai
- Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Asif A Shah
- Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Jeevesh Kumar
- Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Sumana Chattaraj
- Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Aadil Bashir Dar
- Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Utpreksh Patbhaje
- Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Mayank Shrivastava
- Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore 560012, India
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6
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Wang K, Xu L, Shao W, Jin H, Wang Q, Ma M. A Multiple-Fidelity Method for Accurate Simulation of MoS 2 Properties Using JAX-ReaxFF and Neural Network Potentials. J Phys Chem Lett 2024; 15:371-379. [PMID: 38175525 DOI: 10.1021/acs.jpclett.3c03080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Reactive force field (ReaxFF) is a commonly used force field for modeling chemical reactions at the atomic level. Recently, JAX-ReaxFF, combined with automatic differentiation, has been used to efficiently parametrize ReaxFF. However, its analytical formula may lead to inaccurate predictions. While neural network-based potentials (NNPs) trained on density functional theory-labeled data offer a more accurate method, it requires a large amount of training data to be trained from scratch. To overcome these issues, we present a multiple-fidelity method that combines JAX-ReaxFF and NNP and apply the method on MoS2, a promising two-dimensional semiconductor for flexible electronics. By incorporating implicit prior physical information, ReaxFF can serve as a cost-effective way to generate pretraining data, facilitating more accurate simulations of MoS2. Moreover, in the Mo-S-H system, the pretraining strategy can reduce root-mean-square errors of energy by 20%. This approach can be extended to a wide variety of material systems, accelerating their computational research.
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Affiliation(s)
- Kehan Wang
- State Key Laboratory of Tribology in Advanced Equipment (SKLT), Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
- Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China
| | - Longkun Xu
- Samsung Research China - Beijing (SRC-B), Beijing 100102, China
| | - Wei Shao
- Samsung Research China - Beijing (SRC-B), Beijing 100102, China
| | - Haishun Jin
- Samsung Research China - Beijing (SRC-B), Beijing 100102, China
| | - Qiang Wang
- Samsung Research China - Beijing (SRC-B), Beijing 100102, China
| | - Ming Ma
- State Key Laboratory of Tribology in Advanced Equipment (SKLT), Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
- Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China
- Institute of Superlubricity Technology, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518063, Guangdong, China
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7
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Yang R, Ye H, Sun N, Liu W. Spontaneous formation of MoS 2 nanoscrolls from flat monolayers with sulfur vacancies: a molecular dynamics investigation. NANOSCALE 2023; 15:15427-15434. [PMID: 37706225 DOI: 10.1039/d3nr03407k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
The unique physical properties exhibited by one-dimensional nanoscrolls assembled from nanosheets have propelled them into the spotlight of two-dimensional materials research. However, the self-scrolling mechanism of transition metal dichalcogenides has not been unveiled with an appropriate theoretical approach. In this paper, we systematically investigate the spontaneous formation of MoS2 nanoscrolls from flat monolayers by molecular dynamics simulations based on a reactive force field. The sulfur vacancies on one side break the atomic symmetry and the reconstruction acts as the driving force for the curling of the flat nanoribbon. If sulfur vacancies are arranged in a line, clear bending angles of the nanoribbon can be obtained and the angle relies on the direction of the line vacancy. With random sulfur vacancies on the top, spontaneous curling and a time-dependent scrolling process of the nanoribbon can be observed. The interplay between dangling bonds and van der Waals (vdW) interactions plays a pivotal role in the formation process of MoS2 nanoscrolls. With an increasing density of sulfur vacancies, the curvature of the nanoscrolls increases. Meanwhile, the scrolling rate accelerates and the time required for the formation of vdW structures decreases. These results provide theoretical insights into the fabrication of nanoscrolls and pave avenues for tailoring nanoscrolls with different morphologies.
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Affiliation(s)
- Ruhao Yang
- State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China.
| | - Han Ye
- State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China.
| | - Naizhang Sun
- State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China.
| | - Wenjun Liu
- State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China.
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8
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Bachu S, Kowalik M, Huet B, Nayir N, Dwivedi S, Hickey DR, Qian C, Snyder DW, Rotkin SV, Redwing JM, van Duin ACT, Alem N. Role of Bilayer Graphene Microstructure on the Nucleation of WSe 2 Overlayers. ACS NANO 2023. [PMID: 37368885 DOI: 10.1021/acsnano.2c12621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Over the past few years, graphene grown by chemical vapor deposition (CVD) has gained prominence as a template to grow transition metal dichalcogenide (TMD) overlayers. The resulting two-dimensional (2D) TMD/graphene vertical heterostructures are attractive for optoelectronic and energy applications. However, the effects of the microstructural heterogeneities of graphene grown by CVD on the growth of the TMD overlayers are relatively unknown. Here, we present a detailed investigation of how the stacking order and twist angle of CVD graphene influence the nucleation of WSe2 triangular crystals. Through the combination of experiments and theory, we correlate the presence of interlayer dislocations in bilayer graphene with how WSe2 nucleates, in agreement with the observation of a higher nucleation density of WSe2 on top of Bernal-stacked bilayer graphene versus twisted bilayer graphene. Scanning/transmission electron microscopy (S/TEM) data show that interlayer dislocations are present only in Bernal-stacked bilayer graphene but not in twisted bilayer graphene. Atomistic ReaxFF reactive force field molecular dynamics simulations reveal that strain relaxation promotes the formation of these interlayer dislocations with localized buckling in Bernal-stacked bilayer graphene, whereas the strain becomes distributed in twisted bilayer graphene. Furthermore, these localized buckles in graphene are predicted to serve as thermodynamically favorable sites for binding WSex molecules, leading to the higher nucleation density of WSe2 on Bernal-stacked graphene. Overall, this study explores synthesis-structure correlations in the WSe2/graphene vertical heterostructure system toward the site-selective synthesis of TMDs by controlling the structural attributes of the graphene substrate.
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Affiliation(s)
- Saiphaneendra Bachu
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Malgorzata Kowalik
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- 2D Crystal Consortium (2DCC), Materials Research Institute (MRI), The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Benjamin Huet
- 2D Crystal Consortium (2DCC), Materials Research Institute (MRI), The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Applied Research Laboratory (ARL), The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nadire Nayir
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- 2D Crystal Consortium (2DCC), Materials Research Institute (MRI), The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Physics, Karamanoglu Mehmetbey University, Karaman, Turkey 7000
| | - Swarit Dwivedi
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- 2D Crystal Consortium (2DCC), Materials Research Institute (MRI), The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Danielle Reifsnyder Hickey
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- 2D Crystal Consortium (2DCC), Materials Research Institute (MRI), The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Chenhao Qian
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - David W Snyder
- Applied Research Laboratory (ARL), The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Slava V Rotkin
- Materials Research Institute and Department of Engineering Science & Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Joan M Redwing
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- 2D Crystal Consortium (2DCC), Materials Research Institute (MRI), The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Adri C T van Duin
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- 2D Crystal Consortium (2DCC), Materials Research Institute (MRI), The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nasim Alem
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- 2D Crystal Consortium (2DCC), Materials Research Institute (MRI), The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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Kirchhoff B, Jung C, Gaissmaier D, Braunwarth L, Fantauzzi D, Jacob T. In silico characterization of nanoparticles. Phys Chem Chem Phys 2023; 25:13228-13243. [PMID: 37161752 DOI: 10.1039/d3cp01073b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Nanoparticles (NPs) make for intriguing heterogeneous catalysts due to their large active surface area and excellent and often size-dependent catalytic properties that emerge from a multitude of chemically different surface reaction sites. NP catalysts are, in principle, also highly tunable: even small changes to the NP size or surface facet composition, doping with heteroatoms, or changes of the supporting material can significantly alter their physicochemical properties. Because synthesis of size- and shape-controlled NP catalysts is challenging, the ability to computationally predict the most favorable NP structures for a catalytic reaction of interest is an in-demand skill that can help accelerate and streamline the material optimization process. Fundamentally, simulations of NP model systems present unique challenges to computational scientists. Not only must considerable methodological hurdles be overcome in performing calculations with hundreds to thousands of atoms while retaining appropriate accuracy to be able to probe the desired properties. Also, the data generated by simulations of NPs are typically more complex than data from simulations of, for example, single crystal surface models, and therefore often require different data analysis strategies. To this end, the present work aims to review analytical methods and data analysis strategies that have proven useful in extracting thermodynamic trends from NP simulations.
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Affiliation(s)
- Björn Kirchhoff
- Institute of Electrochemistry, Ulm University, Albert-Einstein-Allee 47, 89081 Ulm, Germany.
| | - Christoph Jung
- Institute of Electrochemistry, Ulm University, Albert-Einstein-Allee 47, 89081 Ulm, Germany.
- Helmholtz-Institute Ulm (HIU) Electrochemical Energy Storage, Helmholtz-Straße 16, 89081 Ulm, Germany
- Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Daniel Gaissmaier
- Institute of Electrochemistry, Ulm University, Albert-Einstein-Allee 47, 89081 Ulm, Germany.
- Helmholtz-Institute Ulm (HIU) Electrochemical Energy Storage, Helmholtz-Straße 16, 89081 Ulm, Germany
- Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Laura Braunwarth
- Institute of Electrochemistry, Ulm University, Albert-Einstein-Allee 47, 89081 Ulm, Germany.
| | - Donato Fantauzzi
- Institute of Electrochemistry, Ulm University, Albert-Einstein-Allee 47, 89081 Ulm, Germany.
| | - Timo Jacob
- Institute of Electrochemistry, Ulm University, Albert-Einstein-Allee 47, 89081 Ulm, Germany.
- Helmholtz-Institute Ulm (HIU) Electrochemical Energy Storage, Helmholtz-Straße 16, 89081 Ulm, Germany
- Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany
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10
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Mao Q, Zhang Y, Kowalik M, Nayir N, Chandross M, van Duin ACT. Oxidation and hydrogenation of monolayer MoS2 with compositing agent under environmental exposure: The ReaxFF Mo/Ti/Au/O/S/H force field development and applications. FRONTIERS IN NANOTECHNOLOGY 2022. [DOI: 10.3389/fnano.2022.1034795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
An atomistic modeling tool is essential to an in-depth understanding upon surface reactions of transition metal dichalcogenides (TMDs), such as molybdenum disulfide (MoS2), with the presence of compositing agents, including Ti and Au, under different environmental exposures. We report a new ReaxFF reactive force field parameter set for Mo, Ti, Au, O, S, and H interactions. We apply the force field in a series of molecular dynamics (MD) simulations to unravel the impact of the Ti dopant on the oxidation/hydrogenation behaviors of MoS2 surface. The simulation results reveal that, in the absence of Ti clusters, the MoS2 surface is ruptured and oxidized at elevated temperatures through a process of adsorption followed by dissociation of the O2 molecules on the MoS2 surface during the temperature ramp. When the MoS2 surface is exposed to H2O molecules, surface hydrogenation is most favored, followed by oxidation, then hydroxylation. The introduction of Ti clusters to the systems mitigates the oxidation/hydrogenation of MoS2 at a low or intermediate temperature by capturing the O2/H2O molecules and locking the O/H-related radicals inside the clusters. However, OH− and H3O+ are emitted from the Ti clusters in the H2O environment as temperature rises, and the accelerating hydrogenation of MoS2 is consequently observed at an ultra-high temperature. These findings indicate an important but complex role of Ti dopants in mitigating the oxidation and hydrogenation of MoS2 under different environmental exposures. The possible mechanisms of oxidation and hydrogenation revealed by MD simulations can give an insight to the design of oxidation resistant TMDs and can be useful to the optical, electronic, magnetic, catalytic, and energy harvesting industries.
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11
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Peña-Obeso PJ, Huirache-Acuña R, Ramirez-Zavaleta FI, Rivera JL. Stability of Non-Concentric, Multilayer, and Fully Aligned Porous MoS 2 Nanotubes. MEMBRANES 2022; 12:818. [PMID: 36005733 PMCID: PMC9415411 DOI: 10.3390/membranes12080818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 06/15/2023]
Abstract
Nanotubes made of non-concentric and multiple small layers of porous MoS2 contain inner pores suitable for membrane applications. In this study, molecular dynamics simulations using reactive potentials were employed to estimate the stability of the nanotubes and how their stability compares to macroscopic single- (1L) and double-layer MoS2 flakes. The observed stability was explained in terms of several analyses that focused on the size of the area of full-covered layers, number of layers, polytype, and size of the holes in the 1L flakes. The reactive potential used in this work reproduced experimental results that have been previously reported, including the small dependency of the stability on the polytype, the formation of S-S bonds between inter- and intra-planes, and the limit of stability for two concentric rings forming a single ring-like flake.
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Affiliation(s)
- Pablo Jahir Peña-Obeso
- Facultad de Ingeniería Química, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58000, Mexico
| | - Rafael Huirache-Acuña
- Facultad de Ingeniería Química, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58000, Mexico
| | | | - José Luis Rivera
- Facultad de Ciencias Físico–Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58000, Mexico
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12
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Ponomarev I, Polcar T, Nicolini P. New Reactive Force Field for Simulations of MoS 2 Crystallization. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:9475-9481. [PMID: 35712650 PMCID: PMC9189924 DOI: 10.1021/acs.jpcc.2c01075] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/11/2022] [Indexed: 06/15/2023]
Abstract
We present a new reactive force field (ReaxFF) parameter set for simulations of Mo-S structures. We compare our parameterization to the state-of-the-art ones in their performance against density functional theory (DFT) benchmarks and MoS2 crystallization simulations. Our new force field matches DFT data significantly better than any previously published force fields and provides a realistic layered MoS2 structure in crystallization simulations. It significantly improves the state-of-the-art force fields, which tend to crystallize in the experimentally unknown rock-salt MoS structure. Therefore, our new force field is a good candidate for further development and inclusion of other practically relevant elements, such as O, C, N, and H, which can be used to study the formation and tribological or catalytical properties of molybdenum disulfide.
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Affiliation(s)
- I Ponomarev
- Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, 16627 Prague 6, Czech Republic
| | - T Polcar
- Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, 16627 Prague 6, Czech Republic
| | - P Nicolini
- Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, 16627 Prague 6, Czech Republic
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13
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Sickel J, Asbach M, Gammer C, Bratschitsch R, Kohl H. Quantitative Strain and Topography Mapping of 2D Materials Using Nanobeam Electron Diffraction. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-15. [PMID: 35361302 DOI: 10.1017/s1431927622000502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
It is known that 2D materials can exhibit a nonflat topography, which gives rise to an inherent strain. Since local curvature and strain influence mechanical, optical, and electrical properties, but are often difficult to distinguish from each other, a robust measurement technique is needed. In this study, a novel method is introduced, which is capable of obtaining quantitative strain and topography information of 2D materials with nanometer resolution. Relying on scanning nanobeam electron diffraction (NBED), it is possible to disentangle strain from the local sample slope. Using the positions of the diffraction spots of a specimen at two different tilts to reconstruct the locations and orientations of the reciprocal lattice rods, the local strain and slope can be simultaneously retrieved. We demonstrate the differences to strain measurements from a single NBED map in theory, simulation, and experiment. MoS2 monolayers with different shapes are used as simulation test structures. The slope and height information are recovered, as well as tensile and angular strain which have an absolute difference of less than 0.2% and 0.2° from the theoretical values. An experimental proof of concept using a freely suspended WSe2 monolayer together with a discussion of the accuracy of the method is provided.
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Affiliation(s)
- Julian Sickel
- Physikalisches Institut, WWU Münster, Wilhelm-Klemm-Straße 10, 48149Münster, Germany
| | - Marcel Asbach
- Physikalisches Institut, WWU Münster, Wilhelm-Klemm-Straße 10, 48149Münster, Germany
| | - Christoph Gammer
- Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstrasse 12, Leoben8700, Austria
| | - Rudolf Bratschitsch
- Physikalisches Institut, WWU Münster, Wilhelm-Klemm-Straße 10, 48149Münster, Germany
| | - Helmut Kohl
- Physikalisches Institut, WWU Münster, Wilhelm-Klemm-Straße 10, 48149Münster, Germany
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14
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Xu K, Deng S, Liang T, Cao X, Han M, Zeng X, Zhang Z, Yang N, Wu J. Efficient mechanical modulation of the phonon thermal conductivity of Mo 6S 6 nanowires. NANOSCALE 2022; 14:3078-3086. [PMID: 35138319 DOI: 10.1039/d1nr08505k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Mo6S6 nanowires are emerging as key building blocks for flexible devices and are competitive with carbon nanotubes due to easier separation and functionalization. Here, it is reported the phonon thermal conductivity (κ) of Mo6S6 nanowires via molecular dynamics simulations. It shows a large tunability of low-frequency phonon thermal conductivity (κlf)Amax from 27.2-191 W (m K)-1, an increase of around 702% via mechanical strain. Below critical tension/torsion strain, their phonon thermal conductivity monotonically reduces/enlarges; whereas above this value, an inverse trend is identified. On the other hand, Mo6S6 nanowires show unusual auxetic behavior. The transitions involved in phonon thermal conductivity are molecularly illustrated by a strain-induced crossover in bond configurations and are explained based on a competition mechanism between phonon scattering and group velocity. This study provides insights into the thermal transport and auxetic properties of low-dimensional structures and the thermal management of Mo6S6 nanowire-based systems.
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Affiliation(s)
- Ke Xu
- Department of Physics, Research Institute for Biomimetics and Soft Matter, Jiujiang Research Institute and Fujian Provincial Key Laboratory for Soft Functional Materials Research, Xiamen University, Xiamen 361005, PR China.
| | - Shichen Deng
- State Key Laboratory of Coal Combustion, and School of Energy and Power Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074 PR China.
| | - Ting Liang
- Shenzhen Institute of Advanced Electronic Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, PR China
| | - Xuezheng Cao
- Department of Physics, Research Institute for Biomimetics and Soft Matter, Jiujiang Research Institute and Fujian Provincial Key Laboratory for Soft Functional Materials Research, Xiamen University, Xiamen 361005, PR China.
| | - Meng Han
- Shenzhen Institute of Advanced Electronic Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, PR China
| | - Xiaoliang Zeng
- Shenzhen Institute of Advanced Electronic Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, PR China
| | - Zhisen Zhang
- Department of Physics, Research Institute for Biomimetics and Soft Matter, Jiujiang Research Institute and Fujian Provincial Key Laboratory for Soft Functional Materials Research, Xiamen University, Xiamen 361005, PR China.
| | - Nuo Yang
- State Key Laboratory of Coal Combustion, and School of Energy and Power Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074 PR China.
| | - Jianyang Wu
- Department of Physics, Research Institute for Biomimetics and Soft Matter, Jiujiang Research Institute and Fujian Provincial Key Laboratory for Soft Functional Materials Research, Xiamen University, Xiamen 361005, PR China.
- NTNU Nanomechanical Lab, Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway
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15
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Yilmaz DE, Woodward WH, van Duin ACT. Machine Learning-Assisted Hybrid ReaxFF Simulations. J Chem Theory Comput 2021; 17:6705-6712. [PMID: 34644081 DOI: 10.1021/acs.jctc.1c00523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have developed a machine learning (ML)-assisted Hybrid ReaxFF simulation method ("Hybrid/Reax"), which alternates reactive and non-reactive molecular dynamics simulations with the assistance of ML models to simulate phenomena that require longer time scales and/or larger systems than are typically accessible to ReaxFF. Hybrid/Reax uses a specialized tracking tool during the reactive simulations to further accelerate chemical reactions. Non-reactive simulations are used to equilibrate the system after the reactive simulation stage. ML models are used between reactive and non-reactive stages to predict non-reactive force field parameters of the system based on the updated bond topology. Hybrid/Reax simulation cycles can be continued until the desired chemical reactions are observed. As a case study, this method was used to study the cross-linking of a polyethylene (PE) matrix analogue (decane) with the cross-linking agent dicumyl peroxide (DCP). We were able to run relatively long simulations [>20 million molecular dynamics (MD) steps] on a small test system (4660 atoms) to simulate cross-linking reactions of PE in the presence of DCP. Starting with 80 PE molecules, more than half of them cross-linked by the end of the Hybrid/Reax cycles on a single Xeon processor in under 48 h. This simulation would take approximately 1 month if run with pure ReaxFF MD on the same machine.
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Affiliation(s)
- Dundar E Yilmaz
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | | | - Adri C T van Duin
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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16
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Borge-Durán I, Aias D, Grinberg I. Modelling of high-temperature order-disorder phase transitions of non-stoichiometric Mo 2C and Ti 2C from first principles. Phys Chem Chem Phys 2021; 23:22305-22312. [PMID: 34590649 DOI: 10.1039/d1cp02935e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
High-temperature order-disorder phase transitions play an important role in determining the structure and physical and chemical properties of non-stoichiometric transition metal carbides. Due to the large number of possible carbon vacancy arrangements, it is difficult to study these systems with first-principles calculations. Here, we construct a simple atomistic potential capable of accurately reproducing the energetics of the carbon vacancy arrangements in cubic Mo2C and Ti2C obtained from density functional theory calculations. We show that this potential can be applied to correctly predict the transition temperatures between the ordered and disordered states in Monte Carlo simulations on large supercells and reveal the extend of local order in the disordered phases of Mo2C and Ti2C that show interesting physical and chemical properties. We find that even the high-temperature disordered phase exhibit a relatively high degree of local order as indicated by the relatively small change in the root mean square number of C atom neighbours of Mo/Ti compared to the ordered phase (from 3.0 to 3.1-3.2). This atomistic potential enables the study of how the structure of these carbides can be tuned through the synthesis temperature to control the properties of carbide materials that are related to the degree of disorder in the system such as catalytic activity and electrical conductivity and play an important role in applications of these carbides. Fundamentally, the successful modelling of these carbides suggests that despite the presence of metallic, covalent and ionic interactions, bonding in carbides can be modelled by simple and physically intuitive interatomic potentials.
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Affiliation(s)
| | - Denial Aias
- Chemistry Department, Bar-Ilan University, Ramat-Gan 5290002, Israel.
| | - Ilya Grinberg
- Chemistry Department, Bar-Ilan University, Ramat-Gan 5290002, Israel.
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17
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Zhang J, Wang W, Wang Y, Qiu C, Mao C, Deng S, Wang J. Effect of Cross‐Linked Structures on Mechanical Properties of Styrene‐Butadiene Rubber via Molecular Dynamics Simulation. MACROMOL THEOR SIMUL 2021. [DOI: 10.1002/mats.202100054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Jing Zhang
- Institute of Industrial Catalysis State Key Laboratory Breeding Base of Green‐Chemical Synthesis Technology College of Chemical Engineering Zhejiang University of Technology Hangzhou 310014 P. R. China
| | - Wei Wang
- Institute of Industrial Catalysis State Key Laboratory Breeding Base of Green‐Chemical Synthesis Technology College of Chemical Engineering Zhejiang University of Technology Hangzhou 310014 P. R. China
| | - Yinbin Wang
- Institute of Industrial Catalysis State Key Laboratory Breeding Base of Green‐Chemical Synthesis Technology College of Chemical Engineering Zhejiang University of Technology Hangzhou 310014 P. R. China
| | - Chenglong Qiu
- Institute of Industrial Catalysis State Key Laboratory Breeding Base of Green‐Chemical Synthesis Technology College of Chemical Engineering Zhejiang University of Technology Hangzhou 310014 P. R. China
| | - Chengli Mao
- Shanghai Xinli Power Equipment Research Institute Shanghai 201100 P. R. China
| | - Shengwei Deng
- Institute of Industrial Catalysis State Key Laboratory Breeding Base of Green‐Chemical Synthesis Technology College of Chemical Engineering Zhejiang University of Technology Hangzhou 310014 P. R. China
| | - Jian‐guo Wang
- Institute of Industrial Catalysis State Key Laboratory Breeding Base of Green‐Chemical Synthesis Technology College of Chemical Engineering Zhejiang University of Technology Hangzhou 310014 P. R. China
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18
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Gao C, Yang X, Jiang M, Chen L, Chen Z, Singh CV. Defect evolution behaviors from single sulfur point vacancies to line vacancies in monolayer molybdenum disulfide. Phys Chem Chem Phys 2021; 23:19525-19536. [PMID: 34524293 DOI: 10.1039/d1cp02852a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Two-dimensional monolayer transition metal dichalcogenides (TMDs) are promising candidates for many novel nanoelectronic and optoelectronic applications due to their exceptional electronic, optical, chemical and mechanical properties. Experimentally, single chalcogen point vacancies caused by electron beam irradiation are found to agglomerate into line vacancy defects in monolayer TMDs. Herein, the corresponding defect evolution behaviors from single sulfur point vacancies to line vacancies in the monolayer molybdenum disulfide (MoS2) have been systematically studied using molecular dynamics and first principles calculations. The experimental observations of the defect evolution from single sulfur point vacancies to line vacancies are reproduced at the atomic level. The results indicate that the di-vacancy line defect and a point vacancy separated by a sulfur atom in a line evolve into tri-vacancy line defects, and the di-vacancy line defects can rotate 60° clockwise or counterclockwise. Moreover, two adjacent di-vacancy line defects with an angle of 120° can evolve into tri-vacancy line defects. High temperature and large vacancy concentrations promote the defect evolution from point vacancies to line vacancies. Intriguingly, compared with the randomly distributed point vacancy defects, the line vacancy defects formed after the defect evolution significantly decrease the mechanical properties, such as the ultimate strength, ultimate strain and Young's modulus of monolayer MoS2. In addition, the mechanical properties decrease with increasing vacancy concentration and temperature for the final configurations after defect evolution in monolayer MoS2 with different vacancy concentrations at different temperatures. The band gaps of monolayer MoS2 with line vacancy defects are smaller than those with randomly distributed point vacancy defects. Therefore, our study clarifies the defect evolution behaviors from single sulfur point vacancies to line vacancies in monolayer MoS2 and opens an opportunity for the novel nanoelectronic and optoelectronic applications of monolayer TMDs.
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Affiliation(s)
- Chan Gao
- Department of Materials Science and Engineering, University of Toronto, Toronto, ON M5S 3E4, Canada. .,Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China
| | - Xiaoyong Yang
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, Uppsala 75120, Sweden
| | - Ming Jiang
- Department of Materials Science and Engineering, University of Toronto, Toronto, ON M5S 3E4, Canada.
| | - Lixin Chen
- Department of Materials Science and Engineering, University of Toronto, Toronto, ON M5S 3E4, Canada.
| | - Zhiwen Chen
- Department of Materials Science and Engineering, University of Toronto, Toronto, ON M5S 3E4, Canada.
| | - Chandra Veer Singh
- Department of Materials Science and Engineering, University of Toronto, Toronto, ON M5S 3E4, Canada. .,Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON M5S 3G8, Canada
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19
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Duong PHH, Shin YK, Kuehl VA, Afroz MM, Hoberg JO, Parkinson B, van Duin ACT, Li-Oakey KD. Molecular Interactions and Layer Stacking Dictate Covalent Organic Framework Effective Pore Size. ACS APPLIED MATERIALS & INTERFACES 2021; 13:42164-42175. [PMID: 34415136 DOI: 10.1021/acsami.1c10866] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Interactions among ions, molecules, and confining solid surfaces are universally challenging and intriguing topics. Lacking a molecular-level understanding of such interactions in complex organic solvents perpetuates the intractable challenge of simultaneously achieving high permeance and selectivity in selectively permeable barriers. Two-dimensional covalent organic frameworks (COFs) have demonstrated ultrahigh permeance, high selectivity, and stability in organic solvents. Using reactive force field molecular dynamics modeling and direct experimental comparisons of an imine-linked carboxylated COF (C-COF), we demonstrate that unprecedented organic solvent nanofiltration separation performance can be accomplished by the well-aligned, highly crystalline pores. Furthermore, we show that the effective, as opposed to designed, pore size and solvated solute radii can change dramatically with the solvent environment, providing insights into complex molecular interactions and enabling future application-specific material design and synthesis.
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Affiliation(s)
- Phuoc H H Duong
- Department of Chemical Engineering, University of Wyoming, Laramie, Wyoming 82070, United States
| | - Yun Kyung Shin
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Valerie A Kuehl
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82070, United States
| | - Mohammad M Afroz
- Department of Chemical Engineering, University of Wyoming, Laramie, Wyoming 82070, United States
| | - John O Hoberg
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82070, United States
| | - Bruce Parkinson
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82070, United States
| | - Adri C T van Duin
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Katie D Li-Oakey
- Department of Chemical Engineering, University of Wyoming, Laramie, Wyoming 82070, United States
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20
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Banik S, Loeffler TD, Batra R, Singh H, Cherukara MJ, Sankaranarayanan SKRS. Learning with Delayed Rewards-A Case Study on Inverse Defect Design in 2D Materials. ACS APPLIED MATERIALS & INTERFACES 2021; 13:36455-36464. [PMID: 34288661 DOI: 10.1021/acsami.1c07545] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Defect dynamics in materials are of central importance to a broad range of technologies from catalysis to energy storage systems to microelectronics. Material functionality depends strongly on the nature and organization of defects-their arrangements often involve intermediate or transient states that present a high barrier for transformation. The lack of knowledge of these intermediate states and the presence of this energy barrier presents a serious challenge for inverse defect design, especially for gradient-based approaches. Here, we present a reinforcement learning (RL) [Monte Carlo Tree Search (MCTS)] based on delayed rewards that allow for efficient search of the defect configurational space and allows us to identify optimal defect arrangements in low-dimensional materials. Using a representative case of two-dimensional MoS2, we demonstrate that the use of delayed rewards allows us to efficiently sample the defect configurational space and overcome the energy barrier for a wide range of defect concentrations (from 1.5 to 8% S vacancies)-the system evolves from an initial randomly distributed S vacancies to one with extended S line defects consistent with previous experimental studies. Detailed analysis in the feature space allows us to identify the optimal pathways for this defect transformation and arrangement. Comparison with other global optimization schemes like genetic algorithms suggests that the MCTS with delayed rewards takes fewer evaluations and arrives at a better quality of the solution. The implications of the various sampled defect configurations on the 2H to 1T phase transitions in MoS2 are discussed. Overall, we introduce a RL strategy employing delayed rewards that can accelerate the inverse design of defects in materials for achieving targeted functionality.
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Affiliation(s)
- Suvo Banik
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
- Department of Mechanical and Industrial Engineering, University of Illinois, Chicago, Illinois 60607, United States
| | - Troy David Loeffler
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
- Department of Mechanical and Industrial Engineering, University of Illinois, Chicago, Illinois 60607, United States
| | - Rohit Batra
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Harpal Singh
- Research and Development, Sentient Science Corporation, West Lafayette, Indiana 47906, United States
| | - Mathew J Cherukara
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Subramanian K R S Sankaranarayanan
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
- Department of Mechanical and Industrial Engineering, University of Illinois, Chicago, Illinois 60607, United States
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21
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Guo Y, Zhou X, Lee K, Yoon HC, Xu Q, Wang D. Recent development in friction of 2D materials: from mechanisms to applications. NANOTECHNOLOGY 2021; 32:312002. [PMID: 33882478 DOI: 10.1088/1361-6528/abfa52] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 04/21/2021] [Indexed: 06/12/2023]
Abstract
Two-dimensional (2D) materials with a layered structure are excellent candidates in the field of lubrication due to their unique physical and chemical properties, including weak interlayer interaction and large specific surface area. For the last few decades, graphene has received lots of attention due to its excellent properties. Besides graphene, various new 2D materials (including MoS2, WS2, WSe2, NbSe2, NbTe2, ReS2, TaS2and h-BN etc.) are found to exhibit a low coefficient of friction at the macro- and even micro-scales, which may lead to widespread application in the field of lubrication and anti-wear. This article focuses on the latest development trend in 2D materials in the field of tribology. The review begins with a summary of widely accepted nano-scale friction mechanisms contain surface friction mechanism and interlayer friction mechanism. The following sections report the applications of 2D materials in lubrication and anti-wear as lubricant additives, solid lubricants, and composite lubricating materials. Finally, the research prospects of 2D materials in tribology are presented.
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Affiliation(s)
- Yanbao Guo
- College of Mechanical and Transportation Engineering, China University of Petroleum, Beijing 102249, People's Republic of China
| | - Xuanli Zhou
- College of Mechanical and Transportation Engineering, China University of Petroleum, Beijing 102249, People's Republic of China
| | - Kyungjun Lee
- Department of Mechanical Engineering, Gachon University, Seongnam-si, 13120, Republic of Korea
| | - Hyun Chul Yoon
- Department of Mathematics & Statistics, Texas A&M University-Corpus Christi, Corpus Christi, TX 78412, United States of America
| | - Quan Xu
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, People's Republic of China
| | - Deguo Wang
- College of Mechanical and Transportation Engineering, China University of Petroleum, Beijing 102249, People's Republic of China
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22
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Tsafack T, Bartolucci SF, Maurer JA. Elucidation of Molybdenum Trioxide Sulfurization: Mechanistic Insights into Two-Dimensional Molybdenum Disulfide Growth. J Phys Chem A 2021; 125:1809-1815. [PMID: 33635662 DOI: 10.1021/acs.jpca.0c06964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Powder vaporization is a common method for the generation of large-area, single-crystal, two-dimensional molybdenum disulfide. While commonly employed as a growth method, the fundamental molecular mechanisms are not well understood. Recent ab initio analyses have shown that molybdenum oxysulfide rings play a key role in the sulfurization of molybdenum trioxide from elemental sulfur. In this study, we utilize molecular dynamics simulations with a reactive force field and ab initio calculations to elucidate the reaction pathway of sulfur with molybdenum trioxide. The molecular dynamics simulations demonstrated that for all sulfur allotropes the reaction pathway could be reduced to that of disulfur, trisulfur, or a combination of the two and that molybdenum trioxide can catalyze the decomposition of larger sulfur allotropes. Ab initio calculations were used to illuminate the intermediates and transition states in the reaction pathways for disulfur and trisulfur. Analysis of the temperature dependence of the transition state energies shows that the maximum reaction rates occur between 1000 and 1100 K, which corresponds with commonly reported experimental growth temperatures for molybdenum disulfide.
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Affiliation(s)
- Thierry Tsafack
- US Army, Futures Command, Combat Capabilities Development Command, Watervliet, New York 12189, United States
| | - Stephen F Bartolucci
- US Army, Futures Command, Combat Capabilities Development Command, Watervliet, New York 12189, United States
| | - Joshua A Maurer
- US Army, Futures Command, Combat Capabilities Development Command, Watervliet, New York 12189, United States
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23
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Mejía-Rosales S, Sandoval-Salazar SA, Soria-Sánchez A, Cantú-Sánchez LY. Mechanical properties of MoS2 nanotubes under tension: a molecular dynamics study. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2021.1880577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Sergio Mejía-Rosales
- Centro de Investigación en Ciencias Físico-Matemáticas (CICFIM), Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Nuevo León, Mexico
| | - Saul A. Sandoval-Salazar
- Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Nuevo León, Mexico
| | - Andrés Soria-Sánchez
- Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Nuevo León, Mexico
| | - Laura Y. Cantú-Sánchez
- Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Nuevo León, Mexico
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24
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Shayakhmetova RK, Khamitov EM. ReaxFF Molecular Dynamics Simulation of the Cracking of Components of Vacuum Gasoil in the Presence of a Nickel Nanocluster. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2021. [DOI: 10.1134/s0036024421020229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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25
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Maździarz M. Transferability of Molecular Potentials for 2D Molybdenum Disulphide. MATERIALS 2021; 14:ma14030519. [PMID: 33494529 PMCID: PMC7865456 DOI: 10.3390/ma14030519] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 01/06/2021] [Accepted: 01/18/2021] [Indexed: 12/22/2022]
Abstract
An ability of different molecular potentials to reproduce the properties of 2D molybdenum disulphide polymorphs is examined. Structural and mechanical properties, as well as phonon dispersion of the 1H, 1T and 1T’ single-layer MoS2 (SL MoS2) phases, were obtained using density functional theory (DFT) and molecular statics calculations (MS) with Stillinger-Weber, REBO, SNAP and ReaxFF interatomic potentials. Quantitative systematic comparison and discussion of the results obtained are reported.
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Affiliation(s)
- Marcin Maździarz
- Institute of Fundamental Technological Research Polish Academy of Sciences, 02-106 Warsaw, Poland
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26
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Han J, Cao F, Ji X. Formation mechanism and twist-angle dependent optical properties of bilayer MoS 2 grown by chemical vapor deposition. CrystEngComm 2021. [DOI: 10.1039/d0ce01788d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The main features of phonon vibrations of twisted bilayer MoS2 are tuned by the twist angle.
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Affiliation(s)
- Jinglei Han
- School of Materials Science and Engineering
- South China University of Technology
- Guangzhou 510641
- China
| | - Fa Cao
- School of Materials Science and Engineering
- South China University of Technology
- Guangzhou 510641
- China
| | - Xiaohong Ji
- School of Materials Science and Engineering
- South China University of Technology
- Guangzhou 510641
- China
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27
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Ganeshan K, Shin YK, Osti NC, Sun Y, Prenger K, Naguib M, Tyagi M, Mamontov E, Jiang DE, van Duin ACT. Structure and Dynamics of Aqueous Electrolytes Confined in 2D-TiO 2/Ti 3C 2T 2 MXene Heterostructures. ACS APPLIED MATERIALS & INTERFACES 2020; 12:58378-58389. [PMID: 33337151 DOI: 10.1021/acsami.0c17536] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The synthesis of heterostructures of different two-dimensional (2D) materials offers an approach to combine advantages of different materials constituting the heterostructure and ultimately enhance their performance for applications such as electrochemical energy storage, achieving high energy, and high-power densities. Understanding the behavior of ions and solvents in confinement between these dissimilar layers is critical to understand their performance and control. Considering aqueous electrolytes, we explore the heterostructure of 2D lepidocrocite-type TiO2 (2D-TiO2) and hydroxylated or O-terminated Ti3C2 MXene using ReaxFF molecular dynamics simulations and elastic/quasielastic neutron scattering techniques. Simulating a bilayer water intercalation, we find that the extent of interlayer hydration is impacted most by the surface terminations on the MXene and is marginally affected by 2D-TiO2. However, the introduction of 2D-TiO2 decreases the water self-diffusion due to the notch sites (i.e., surface oxygen ridges) entrapping water molecules. Intercalating alkali cations into the heterostructures, we find that Li+ is predominantly adsorbed at the 2D-TiO2 surface instead of the MXenes with the preferential occupation of the notch sites. In contrast, Na+ forms a planar solvation with water, while K+ is adsorbed both at the O-terminated MXene and 2D-TiO2. This behavior is altered when OH-terminated MXene is involved-the repulsion from the protons on the MXene surface forces the K+ ions to be adsorbed exclusively to 2D-TiO2, while Na+ retains some of its solvation in the water layer due to its smaller size. In OH-terminated MXenes, we see a consistent transfer of protons from the MXene surface toward 2D-TiO2, implying a greater capacity to store protons in the heterostructures. Of the three cations simulated, Na+ hinders the proton migration the least and Li+ the most because of its position near the 2D-TiO2 surface. Therefore, 2D-TiO2/MXene heterostructures are likely to exhibit a higher energy density but lower power density, especially with Na+ intercalation.
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Affiliation(s)
- Karthik Ganeshan
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, State College, Pennsylvania 16802, United States
| | - Yun Kyung Shin
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, State College, Pennsylvania 16802, United States
| | - Naresh C Osti
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Yangyunli Sun
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Kaitlyn Prenger
- Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, United States
| | - Michael Naguib
- Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, United States
| | - Madhusudan Tyagi
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
- Department of Materials Science, University of Maryland, College Park, Maryland 20742, United States
| | - Eugene Mamontov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - De-En Jiang
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Adri C T van Duin
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, State College, Pennsylvania 16802, United States
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28
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Darlington TP, Carmesin C, Florian M, Yanev E, Ajayi O, Ardelean J, Rhodes DA, Ghiotto A, Krayev A, Watanabe K, Taniguchi T, Kysar JW, Pasupathy AN, Hone JC, Jahnke F, Borys NJ, Schuck PJ. Imaging strain-localized excitons in nanoscale bubbles of monolayer WSe 2 at room temperature. NATURE NANOTECHNOLOGY 2020; 15:854-860. [PMID: 32661371 DOI: 10.1038/s41565-020-0730-5] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 06/03/2020] [Indexed: 05/23/2023]
Abstract
In monolayer transition-metal dichalcogenides, localized strain can be used to design nanoarrays of single photon sources. Despite strong empirical correlation, the nanoscale interplay between excitons and local crystalline structure that gives rise to these quantum emitters is poorly understood. Here, we combine room-temperature nano-optical imaging and spectroscopic analysis of excitons in nanobubbles of monolayer WSe2 with atomistic models to study how strain induces nanoscale confinement potentials and localized exciton states. The imaging of nanobubbles in monolayers with low defect concentrations reveals localized excitons on length scales of around 10 nm at multiple sites around the periphery of individual nanobubbles, in stark contrast to predictions of continuum models of strain. These results agree with theoretical confinement potentials atomistically derived from the measured topographies of nanobubbles. Our results provide experimental and theoretical insights into strain-induced exciton localization on length scales commensurate with exciton size, realizing key nanoscale structure-property information on quantum emitters in monolayer WSe2.
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Affiliation(s)
| | - Christian Carmesin
- Institute for Theoretical Physics, University of Bremen, Bremen, Germany
| | - Matthias Florian
- Institute for Theoretical Physics, University of Bremen, Bremen, Germany
| | - Emanuil Yanev
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Obafunso Ajayi
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Jenny Ardelean
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Daniel A Rhodes
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Augusto Ghiotto
- Department of Physics, Columbia University, New York, NY, USA
| | | | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba, Japan
| | | | - Jeffrey W Kysar
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | | | - James C Hone
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Frank Jahnke
- Institute for Theoretical Physics, University of Bremen, Bremen, Germany.
| | - Nicholas J Borys
- Department of Physics, Montana State University, Bozeman, MT, USA.
| | - P James Schuck
- Department of Mechanical Engineering, Columbia University, New York, NY, USA.
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29
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Huang H, Liu N, Wang X, Luo Q, Huang X, Wang X, Zhong M, Zhang H. DFT calculation of hydrothermal mechanism on preparation of MoS 2. J Mol Model 2020; 26:257. [PMID: 32886185 DOI: 10.1007/s00894-020-04521-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 08/26/2020] [Indexed: 11/27/2022]
Abstract
Basing on the simplest hydrothermal system containing deionized water, hexa-ammonium molybdate, and thiourea, hydrothermal mechanism on preparation of MoS2 was studied by DFT calculation. Hydrothermal process was divided into four steps which covered ionization equilibrium, the hydrolysis of CS(NH2)2, the formation of intermediates, and the formation of MoS2. Ionization equilibrium occurs at normal condition and determines the existence of Mo in the form of molybdic acid. Thiourea hydrolysis is rate-determining step in the process of hydrothermal which contains 10 elementary reactions. The formation of intermediates includes hydrogen transfer, dehydration, and vulcanization three steps which contain 18 elementary reactions, and the energy barrier of vulcanization is the highest. The formation of MoS2 is divided into two steps, the first step is that MoO(OH)(SH)3.H2O reacts with MoO (SH)4.H2O to form layer MoS2, and the second step is a very fast process that can affect the morphology of the products.
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Affiliation(s)
- He Huang
- College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi, 830046, People's Republic of China
| | - Na Liu
- College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi, 830046, People's Republic of China
| | - Xueying Wang
- College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi, 830046, People's Republic of China
| | - Qinglong Luo
- College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi, 830046, People's Republic of China
| | - Xueli Huang
- College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi, 830046, People's Republic of China.
| | - Xuefeng Wang
- College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi, 830046, People's Republic of China
| | - Mei Zhong
- College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi, 830046, People's Republic of China
| | - Hongyu Zhang
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao, 266580, People's Republic of China
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30
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Izadi ME, Maghari A, Zhang W, van Duin ACT. Reactive molecular dynamics simulation for isotope-exchange reactions in H/D systems: ReaxFF HD development. J Chem Phys 2020; 152:224111. [PMID: 32534519 DOI: 10.1063/5.0008386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
To investigate the chemical isotope-exchange reactions within a system composed of a mixture of hydrogen and deuterium (H/D) in the plasma media, the ReaxFFHD potential was parameterized against an appropriate quantum mechanics (QM)-based training set. These QM data involve structures and energies related to bond dissociation, angle distortion, and an exchange reaction of the tri-atomic molecular ions, H3 +, D3 +, H2D+, and D2H+, produced in the hydrogen plasma. Using the ReaxFFHD potential, a range of reactive molecular dynamics simulations were performed on different mixtures of H/D systems. Analysis of the reactions involved in the production of these tri-atomic molecular ions was carried out over 1 ns simulations. The results show that the ReaxFFHD potential can properly model isotope-exchange reactions of tri-atomic molecular ions and that it also has a perfect transferability to reactions taking place in these systems. In our simulations, we observed some intermediate molecules (H2, D2, and HD) that undergo secondary reactions to form the tri-atomic molecular ions as the most likely products in the hydrogen plasma. Moreover, there remains a preference for D in the produced molecular ions, which is related to the lower zero-point energy of the D-enriched species, showing the isotope effects at the heart of the ReaxFFHD potential.
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Affiliation(s)
- Mohammad Ebrahim Izadi
- Department of Physical Chemistry, School of Chemistry, College of Science, University of Tehran, Tehran, Iran
| | - Ali Maghari
- Department of Physical Chemistry, School of Chemistry, College of Science, University of Tehran, Tehran, Iran
| | - Weiwei Zhang
- Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Adri C T van Duin
- Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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31
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Wang W, Wen T, Bai H, Zhao Y, Ni J, Yang L, Xia L, Song S. Adsorption toward Cu(II) and inhibitory effect on bacterial growth occurring on molybdenum disulfide-montmorillonite hydrogel surface. CHEMOSPHERE 2020; 248:126025. [PMID: 32006838 DOI: 10.1016/j.chemosphere.2020.126025] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 01/22/2020] [Accepted: 01/24/2020] [Indexed: 06/10/2023]
Abstract
Novel molybdenum disulfide-montmorillonite (MoS2@2DMMT) hydrogels for Cu(II) removal and inhibition on bacterial growth were successfully prepared. MoS2 was first in-situ growth onto 2DMMT platelet through hydrothermal method and then cross-linked with organic reagents to form hydrogels. The flower-like structure of synthesized MoS2 could be clearly observed in MoS2@2DMMT by SEM. The synthesized hydrogels possessed a three-dimensional macroporous structure, offering a free access for contaminants to get inside and combine with the active sites. Adsorption tests revealed that efficient Cu(II) removal (65.75 mg/g) could be achieved within a short time (30 min) at pH 5. The pseudo-second-order kinetics model and Langmuir isotherm model indicated the existence of chemisorption and monolayer absorption for Cu(II) onto MoS2@2DMMT hydrogels. Characterizations of EDS and XPS indicated that Cu(II) reacted with groups of carboxyl, hydroxyl and amidogen. Bacteriostatic tests revealed that almost a complete bacteriostatic was achieved with just small dosage (0.8 mg/mL) of MoS2@2DMMT hydrogels after the Cu(II) removal under the normal illumination. The mechanism was ascribed to the destructive effect of Cu(II) to the cytomembrane and the damage of reactive oxygen species (ROS) to the DNA. Such hydrogel not only provided insights for treating co-existing contaminates, but also guides for designing novel polymer materials from two-dimensional (2D) nano-materials.
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Affiliation(s)
- Wei Wang
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China
| | - Tong Wen
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China
| | - Haoyu Bai
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China
| | - Yunliang Zhao
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China.
| | - Jiaming Ni
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China
| | - Lang Yang
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China
| | - Ling Xia
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China
| | - Shaoxian Song
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China; Hubei Provincial Collaborative Innovation Center for High Efficient Utilization of Vanadium Resources, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China.
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32
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Joyner J, Oliveira EF, Yamaguchi H, Kato K, Vinod S, Galvao DS, Salpekar D, Roy S, Martinez U, Tiwary CS, Ozden S, Ajayan PM. Graphene Supported MoS 2 Structures with High Defect Density for an Efficient HER Electrocatalysts. ACS APPLIED MATERIALS & INTERFACES 2020; 12:12629-12638. [PMID: 32045208 DOI: 10.1021/acsami.9b17713] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The development of novel efficient and robust electrocatalysts with sufficient active sites is one of the key parameters for hydrogen evolution reactions (HER) catalysis, which plays a key role in hydrogen production for clean energy harvesting. Recently, two-dimensional (2D) materials, especially those based upon transition metal dichalcogenides such as molybdenum disulfide (MoS2), have gained attention for the catalysis of hydrogen production because of their exceptional properties. Innovative strategies have been developed to engineer these material systems for improvements in their catalytic activity. Toward this aim, the facile growth of MoS2 clusters by sulfurization of molybdenum dioxide (MoO2) particles supported on reduced graphene oxide (rGO) foams using the chemical vapor deposition (CVD) method is reported. This approach created various morphologies of MoS2 with large edges and defect densities on the basal plane of rGO supported MoS2 structures, which are considered as active sites for HER catalysis. In addition, MoS2 nanostructures on the surface of the porous rGO network show robust physical interactions, such as van der Waals and π-π interactions between MoS2 and rGO. These features result in an improved process to yield a suitable HER catalyst. In order to gain a better understanding of the improvement of this MoS2-based HER catalyst, fully atomistic molecular dynamics (MD) simulations of different defect geometries were also performed.
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Affiliation(s)
- Jarin Joyner
- Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Eliezer F Oliveira
- Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
- Applied Physics Department, State University of Campinas (UNICAMP), Campinas, Sao Paolo 13083-970, Brazil
- Center for Computational Engineering & Sciences (CCES), State University of Campinas-UNICAMP, Campinas, Sao Paolo 13083-970, Brazil
| | - Hisato Yamaguchi
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Keiko Kato
- Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
| | - Soumya Vinod
- Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
| | - Douglas S Galvao
- Applied Physics Department, State University of Campinas (UNICAMP), Campinas, Sao Paolo 13083-970, Brazil
- Center for Computational Engineering & Sciences (CCES), State University of Campinas-UNICAMP, Campinas, Sao Paolo 13083-970, Brazil
| | - Devashish Salpekar
- Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
| | - Soumyabrata Roy
- Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
| | - Ulises Martinez
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Chandra S Tiwary
- Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
- Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, Kharagpur 382355, India
| | - Sehmus Ozden
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Princeton Center for Complex Materials, Princeton University, Princeton, New Jersey 08540, United States
- Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08540, United States
- Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08540, United States
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08540, United States
| | - Pulickel M Ajayan
- Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
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33
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Yu J, Kim S, Ertekin E, van der Zande AM. Material-Dependent Evolution of Mechanical Folding Instabilities in Two-Dimensional Atomic Membranes. ACS APPLIED MATERIALS & INTERFACES 2020; 12:10801-10808. [PMID: 32036649 DOI: 10.1021/acsami.9b20909] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Inducing and controlling three-dimensional deformations in monolayer two-dimensional materials is important for applications from stretchable electronics to origami nanoelectromechanical systems. For these applications, it is critical to understand how the properties of different materials influence the morphologies of two-dimensional atomic membranes under mechanical loading. Here, we systematically investigate the evolution of mechanical folding instabilities in uniaxially compressed monolayer graphene and MoS2 on a soft polydimethylsiloxane substrate. We examine the morphology of the compressed membranes using atomic force microscopy for compression from 0 to 33%. We find the membranes display roughly evenly spaced folds and observe two distinct stress release mechanisms under increasing compression. At low compression, the membranes delaminate to generate new folds. At higher compression, the membranes slip over the surface to enlarge existing folds. We observe a material-dependent transition between these two behaviors at a critical fold spacing of 1000 ± 250 nm for graphene and 550 ± 20 nm for MoS2. We establish a simple shear-lag model which attributes the transition to a competition between static friction and adhesion and gives the maximum interfacial static friction on polydimethylsiloxane of 3.8 ± 0.8 MPa for graphene and 7.7 ± 2.5 MPa for MoS2. Furthermore, in graphene, we observe an additional transition from standing folds to fallen folds at 8.5 ± 2.3 nm fold height. These results provide a framework to control the nanoscale fold structure of monolayer atomic membranes, which is a critical step in deterministically designing stretchable or foldable nanosystems based on two-dimensional materials.
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Affiliation(s)
- Jaehyung Yu
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - SunPhil Kim
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Elif Ertekin
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 S Goodwin Avenue MC-230, Urbana, Illinois 61801, United States
| | - Arend M van der Zande
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 S Goodwin Avenue MC-230, Urbana, Illinois 61801, United States
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34
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Ries L, Petit E, Michel T, Diogo CC, Gervais C, Salameh C, Bechelany M, Balme S, Miele P, Onofrio N, Voiry D. Enhanced sieving from exfoliated MoS 2 membranes via covalent functionalization. NATURE MATERIALS 2019; 18:1112-1117. [PMID: 31451779 DOI: 10.1038/s41563-019-0464-7] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 07/17/2019] [Indexed: 05/02/2023]
Abstract
Nanolaminate membranes made of two-dimensional materials such as graphene oxide are promising candidates for molecular sieving via size-limited diffusion in the two-dimensional capillaries, but high hydrophilicity makes these membranes unstable in water. Here, we report a nanolaminate membrane based on covalently functionalized molybdenum disulfide (MoS2) nanosheets. The functionalized MoS2 membranes demonstrate >90% and ~87% rejection for micropollutants and NaCl, respectively, when operating under reverse osmotic conditions. The sieving performance and water flux of the functionalized MoS2 membranes are attributed both to control of the capillary widths of the nanolaminates and to control of the surface chemistry of the nanosheets. We identify small hydrophobic functional groups, such as the methyl group, as the most promising for water purification. Methyl- functionalized nanosheets show high water permeation rates as confirmed by our molecular dynamic simulations, while maintaining high NaCl rejection. Control of the surface chemistry and the interlayer spacing therefore offers opportunities to tune the selectivity of the membranes while enhancing their stability.
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Affiliation(s)
- Lucie Ries
- Institut Européen des Membranes, IEM, UMR 5635, Université Montpellier, ENSCM, CNRS, Montpellier, France
| | - Eddy Petit
- Institut Européen des Membranes, IEM, UMR 5635, Université Montpellier, ENSCM, CNRS, Montpellier, France
| | - Thierry Michel
- Laboratoire Charles Coulomb, L2C, Université de Montpellier, CNRS, Montpellier, France
| | | | - Christel Gervais
- Sorbonne Université, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, Paris, France
- Institut Universitaire de France, MESRI, Paris, France
| | - Chrystelle Salameh
- Institut Européen des Membranes, IEM, UMR 5635, Université Montpellier, ENSCM, CNRS, Montpellier, France
| | - Mikhael Bechelany
- Institut Européen des Membranes, IEM, UMR 5635, Université Montpellier, ENSCM, CNRS, Montpellier, France
| | - Sébastien Balme
- Institut Européen des Membranes, IEM, UMR 5635, Université Montpellier, ENSCM, CNRS, Montpellier, France
| | - Philippe Miele
- Institut Européen des Membranes, IEM, UMR 5635, Université Montpellier, ENSCM, CNRS, Montpellier, France
- Institut Universitaire de France, MESRI, Paris, France
| | - Nicolas Onofrio
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China.
| | - Damien Voiry
- Institut Européen des Membranes, IEM, UMR 5635, Université Montpellier, ENSCM, CNRS, Montpellier, France.
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35
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Rahnamoun A, Engelhart DP, Humagain S, Koerner H, Plis E, Kennedy WJ, Cooper R, Greenbaum SG, Hoffmann R, van Duin AC. Chemical dynamics characteristics of Kapton polyimide damaged by electron beam irradiation. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.05.035] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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36
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Structural, electronic and adsorption properties of monolayer 2H-MoS2 on graphene substrates: A computational study. INORG CHEM COMMUN 2019. [DOI: 10.1016/j.inoche.2019.05.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Lin C, Chen X, Zou X. Phonon-Grain-Boundary-Interaction-Mediated Thermal Transport in Two-Dimensional Polycrystalline MoS 2. ACS APPLIED MATERIALS & INTERFACES 2019; 11:25547-25555. [PMID: 31273972 DOI: 10.1021/acsami.9b06196] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Although dislocations and grain boundaries (GBs) are ubiquitous in large-scale MoS2 samples, their interaction with phonons, which plays an important role in determining the lattice thermal conductivity of polycrystalline MoS2, remains elusive. Here, we perform a systematic study of the heat transport in two-dimensional polycrystalline MoS2 by both molecular dynamics simulation and atomic Green's function method. Our results indicate that the thermal boundary conductance of GBs of MoS2 is in the range from 6.4 × 108 to 35.3 × 108 W m-2 K-1, which is closely correlated with the overlap between the vibrational density of states of GBs and those of the pristine lattice, as well as the GB energy. It is found that the GBs strongly scatter the phonons with frequency larger than 2 THz, accompanied by a pronounced phonon localization effect and significantly reduced phonon group velocities. Furthermore, by comparing the results from realistic polycrystalline MoS2 to those from different theoretical models, we observe that the Casimir model is broken down and detailed phonon dynamics at a specific GB should be taken into account to accurately describe the phonon transport in polycrystalline materials. Our findings will provide useful guidelines for designing efficient thermoelectric and thermal management materials based on phonon-GB interaction.
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Affiliation(s)
- Changpeng Lin
- Shenzhen Geim Graphene Center (SGC), Tsinghua-Berkeley Shenzhen Institute (TBSI) , Tsinghua University , Shenzhen 518055 , People's Republic of China
| | - Xiaobin Chen
- School of Science and State Key Laboratory on Tunable Laser Technology and Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System , Harbin Institute of Technology , Shenzhen 518055 , People's Republic of China
- Collaborative Innovation Center of Extreme Optics , Shanxi University , Taiyuan 030006 , People's Republic of China
| | - Xiaolong Zou
- Shenzhen Geim Graphene Center (SGC), Tsinghua-Berkeley Shenzhen Institute (TBSI) , Tsinghua University , Shenzhen 518055 , People's Republic of China
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38
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Zhu S, Pochet P, Johnson HT. Controlling Rotation of Two-Dimensional Material Flakes. ACS NANO 2019; 13:6925-6931. [PMID: 31082256 DOI: 10.1021/acsnano.9b01794] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Interlayer rotational alignment in van der Waals (vdW) structures of two-dimensional (2D) materials couples strongly to electronic properties and, therefore, has significant technological implications. Nevertheless, controlling the rotation of an arbitrary 2D material flake remains a challenge in the development of rotation-tunable electronics, for the emerging field of twistronics. In this article, we reveal a general moiré-driven mechanism that governs the interlayer rotation. Controlling the moiré can therefore hold promise for controlling the interlayer rotation. We further demonstrate mismatch strain engineering as a useful tool to design the interlayer rotation via changing the energy landscape of moiré within a finite-sized region. The robustness and programmable nature of our approach arise from moiré symmetry, energetics, and mechanics. Our approach provides another possibility to the on-demand design of rotation-tunable electronics.
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Affiliation(s)
- Shuze Zhu
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Pascal Pochet
- Laboratory of Atomistic Simulation (L_Sim) , Univ. Grenoble Alpes 38054 Grenoble , France
| | - Harley T Johnson
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
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Chan H, Sasikumar K, Srinivasan S, Cherukara M, Narayanan B, Sankaranarayanan SKRS. Machine learning a bond order potential model to study thermal transport in WSe 2 nanostructures. NANOSCALE 2019; 11:10381-10392. [PMID: 31107489 DOI: 10.1039/c9nr02873k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Nanostructures of transition metal di-chalcogenides (TMDCs) exhibit exotic thermal, chemical and electronic properties, enabling diverse applications from thermoelectrics and catalysis to nanoelectronics. The thermal properties of these nanoscale TMDCs are of particular interest for thermoelectric applications. Thermal transport studies on nanotubes and nanoribbons remain intractable to first principles calculations whereas existing classical molecular models treat the two chalcogen layers in a monolayer with different atom types; this imposes serious limitations in studying multi-layered TMDCs and dynamical phenomena such as nucleation and growth. Here, we overcome these limitations using machine learning (ML) and introduce a bond order potential (BOP) trained against first principles training data to capture the structure, dynamics, and thermal transport properties of a model TMDC such as WSe2. The training is performed using a hierarchical objective genetic algorithm workflow to accurately describe the energetics, as well as thermal and mechanical properties of a free-standing sheet. As a representative case study, we perform molecular dynamics simulations using the ML-BOP model to study the structure and temperature-dependent thermal conductivity of WSe2 tubes and ribbons of different chiralities. We observe slightly higher thermal conductivities along the armchair direction than zigzag for WSe2 monolayers but the opposite effect for nanotubes, especially of smaller diameters. We trace the origin of these differences to the anisotropy in thermal transport and the restricted momentum selection rules for phonon-phonon Umpklapp scattering. The developed ML-BOP model is of broad interest and will facilitate studies on nucleation and growth of low dimensional WSe2 structures as well as their transport properties for thermoelectric and thermal management applications.
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Affiliation(s)
- Henry Chan
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne IL, USA.
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Carmesin C, Lorke M, Florian M, Erben D, Schulz A, Wehling TO, Jahnke F. Quantum-Dot-Like States in Molybdenum Disulfide Nanostructures Due to the Interplay of Local Surface Wrinkling, Strain, and Dielectric Confinement. NANO LETTERS 2019; 19:3182-3186. [PMID: 30945871 DOI: 10.1021/acs.nanolett.9b00641] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The observation of quantum light emission from atomically thin transition metal dichalcogenides has opened a new field of applications for these material systems. The corresponding excited charge-carrier localization has been linked to defects and strain, while open questions remain regarding the microscopic origin. We demonstrate that the bending rigidity of these materials leads to wrinkling of the two-dimensional layer. The resulting strain field facilitates strong carrier localization due to its pronounced influence on the band gap. Additionally, we consider charge carrier confinement due to local changes of the dielectric environment and show that both effects contribute to modified electronic states and optical properties. The interplay of surface wrinkling, strain-induced confinement, and local changes of the dielectric environment is demonstrated for the example of nanobubbles that form when monolayers are deposited on substrates or other two-dimensional materials.
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Zhu S, Johnson HT. Moiré-templated strain patterning in transition-metal dichalcogenides and application in twisted bilayer MoS 2. NANOSCALE 2018; 10:20689-20701. [PMID: 30398273 DOI: 10.1039/c8nr06269b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
To take full advantage of the electronic properties of transition-metal dichalcogenides and their vdW layered structures, it will be necessary to control the local electronic structure, on which the effect of lattice deformation is significant. Nevertheless, a general approach to programming nanoscale morphology in TMD materials, which would permit local strain engineering, has proven elusive. In this work, we propose a general moiré-templated nanoscale morphology engineering method based on bilayer TMDs. The moiré superlattice plays the key role in enforcing in-plane periodical variations in local interlayer spacing and potential energy. Upon global in-plane compression, the high-energy, large-interlayer-separation stacking domains serve as periodic buckling initiation sites. The buckled features can be thus precisely correlated to the moiré periodicity. The spatial profile of the buckled morphology and strain field are possible to be pre-determined, providing a bridge to the electronics and optoelectronics design. We take twisted bilayer MoS2 to demonstrate our approach. We further demonstrate how the morphology can modulate band gap and optical absorption of a MoS2 monolayer, envisioned as a potential constituent layer in a Moiré-templated, strain-engineered vdW heterostructure of TMDs. The robustness and programmable nature of our approach arise from superlattice symmetry, energetics and mechanics. Our approach provides a new strategy for on-demand design of morphology and local strain in TMDs under mechanical deformation.
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Affiliation(s)
- Shuze Zhu
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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Patra TK, Zhang F, Schulman DS, Chan H, Cherukara MJ, Terrones M, Das S, Narayanan B, Sankaranarayanan SKRS. Defect Dynamics in 2-D MoS 2 Probed by Using Machine Learning, Atomistic Simulations, and High-Resolution Microscopy. ACS NANO 2018; 12:8006-8016. [PMID: 30074765 DOI: 10.1021/acsnano.8b02844] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Structural defects govern various physical, chemical, and optoelectronic properties of two-dimensional transition-metal dichalcogenides (TMDs). A fundamental understanding of the spatial distribution and dynamics of defects in these low-dimensional systems is critical for advances in nanotechnology. However, such understanding has remained elusive primarily due to the inaccessibility of (a) necessary time scales via standard atomistic simulations and (b) required spatiotemporal resolution in experiments. Here, we take advantage of supervised machine learning, in situ high-resolution transmission electron microscopy (HRTEM) and molecular dynamics (MD) simulations to overcome these limitations. We combine genetic algorithms (GA) with MD to investigate the extended structure of point defects, their dynamical evolution, and their role in inducing the phase transition between the semiconducting (2H) and metallic (1T) phase in monolayer MoS2. GA-based structural optimization is used to identify the long-range structure of randomly distributed point defects (sulfur vacancies) for various defect densities. Regardless of the density, we find that organization of sulfur vacancies into extended lines is the most energetically favorable. HRTEM validates these findings and suggests a phase transformation from the 2H-to-1T phase that is localized near these extended defects when exposed to high electron beam doses. MD simulations elucidate the molecular mechanism driving the onset of the 2H to 1T transformation and indicate that finite amounts of 1T phase can be retained by increasing the defect concentration and temperature. This work significantly advances the current understanding of defect structure/evolution and structural transitions in 2D TMDs, which is crucial for designing nanoscale devices with desired functionality.
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Reshmi S, Akshaya MV, Satpati B, Basu PK, Bhattacharjee K. Structural stability of coplanar 1T-2H superlattice MoS 2 under high energy electron beam. NANOTECHNOLOGY 2018; 29:205604. [PMID: 29498935 DOI: 10.1088/1361-6528/aab3c3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Coplanar heterojunctions composed of van der Waals layered materials with different structural polymorphs have drawn immense interest recently due to low contact resistance and high carrier injection rate owing to low Schottky barrier height. Present research has largely focused on efficient exfoliation of these layered materials and their restacking to achieve better performances. We present here a microwave assisted easy, fast and efficient route to induce high concentration of metallic 1T phase in the original 2H matrix of exfoliated MoS2 layers and thus facilitating the formation of a 1T-2H coplanar superlattice phase. High resolution transmission electron microscopy (HRTEM) investigations reveal formation of highly crystalline 1T-2H hybridized structure with sharp interface and disclose the evidence of surface ripplocations within the same exfoliated layer of MoS2. In this work, the structural stability of 1T-2H superlattice phase during HRTEM measurements under an electron beam of energy 300 keV is reported. This structural stability could be either associated to the change in electronic configuration due to induction of the restacked hybridized phase with 1T- and 2H-regions or to the formation of the surface ripplocations. Surface ripplocations can act as an additional source of scattering centers to the electron beam and also it is possible that a pulse train of propagating ripplocations can sweep out the defects via interaction from specific areas of MoS2 sheets.
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Affiliation(s)
- S Reshmi
- Department of Physics, Indian Institute of Space Science and Technology (IIST), Thiruvananthapuram 695 547, Kerala, India
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Van Thanh V, Hung NT, Van Truong D. Charge-induced electromechanical actuation of Mo- and W-dichalcogenide monolayers. RSC Adv 2018; 8:38667-38672. [PMID: 35559053 PMCID: PMC9090621 DOI: 10.1039/c8ra08248k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 11/13/2018] [Indexed: 12/14/2022] Open
Abstract
Using first-principle density functional calculations, we investigate electromechanical properties of two-dimensional MX2 (M = Mo, W; X = S, Se, Te) monolayers with the 1H and 1T structures as a function of charge doping for both electron and hole doping.
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Affiliation(s)
- Vuong Van Thanh
- Department of Design of Machinery and Robot
- School of Mechanical Engineering
- Hanoi University of Science and Technology
- Hanoi
- Vietnam
| | | | - Do Van Truong
- Department of Mechatronics
- School of Mechanical Engineering
- Hanoi University of Science and Technology
- Hanoi
- Vietnam
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Hong S, Krishnamoorthy A, Rajak P, Tiwari S, Misawa M, Shimojo F, Kalia RK, Nakano A, Vashishta P. Computational Synthesis of MoS 2 Layers by Reactive Molecular Dynamics Simulations: Initial Sulfidation of MoO 3 Surfaces. NANO LETTERS 2017; 17:4866-4872. [PMID: 28671475 DOI: 10.1021/acs.nanolett.7b01727] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Transition metal dichalcogenides (TMDC) like MoS2 are promising candidates for next-generation electric and optoelectronic devices. These TMDC monolayers are typically synthesized by chemical vapor deposition (CVD). However, despite significant amount of empirical work on this CVD growth of monolayered crystals, neither experiment nor theory has been able to decipher mechanisms of selection rules for different growth scenarios, or make predictions of optimized environmental parameters and growth factors. Here, we present an atomic-scale mechanistic analysis of the initial sulfidation process on MoO3 surfaces using first-principles-informed ReaxFF reactive molecular dynamics (RMD) simulations. We identify a three-step reaction process associated with synthesis of the MoS2 samples from MoO3 and S2 precursors: O2 evolution and self-reduction of the MoO3 surface; SO/SO2 formation and S2-assisted reduction; and sulfidation of the reduced surface and Mo-S bond formation. These atomic processes occurring during early stage MoS2 synthesis, which are consistent with experimental observations and existing theoretical literature, provide valuable input for guided rational synthesis of MoS2 and other TMDC crystals by the CVD process.
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Affiliation(s)
- Sungwook Hong
- Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Computer Science, Department of Chemical Engineering & Materials Science, and Department of Biological Sciences, University of Southern California , Los Angeles, California 90089-0242, United States
| | - Aravind Krishnamoorthy
- Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Computer Science, Department of Chemical Engineering & Materials Science, and Department of Biological Sciences, University of Southern California , Los Angeles, California 90089-0242, United States
| | - Pankaj Rajak
- Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Computer Science, Department of Chemical Engineering & Materials Science, and Department of Biological Sciences, University of Southern California , Los Angeles, California 90089-0242, United States
| | - Subodh Tiwari
- Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Computer Science, Department of Chemical Engineering & Materials Science, and Department of Biological Sciences, University of Southern California , Los Angeles, California 90089-0242, United States
| | - Masaaki Misawa
- Department of Physics, Kumamoto University , Kumamoto 860-8555, Japan
| | - Fuyuki Shimojo
- Department of Physics, Kumamoto University , Kumamoto 860-8555, Japan
| | - Rajiv K Kalia
- Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Computer Science, Department of Chemical Engineering & Materials Science, and Department of Biological Sciences, University of Southern California , Los Angeles, California 90089-0242, United States
| | - Aiichiro Nakano
- Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Computer Science, Department of Chemical Engineering & Materials Science, and Department of Biological Sciences, University of Southern California , Los Angeles, California 90089-0242, United States
| | - Priya Vashishta
- Collaboratory for Advanced Computing and Simulations, Department of Physics & Astronomy, Department of Computer Science, Department of Chemical Engineering & Materials Science, and Department of Biological Sciences, University of Southern California , Los Angeles, California 90089-0242, United States
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