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Controlled Syntheses and Multifunctional Applications of Two-Dimensional Metallic Transition Metal Dichalcogenides

Accounts of materials Research 2021年第9期2卷 751-763页

作者： Peng Wang Yahuan Huan Pengfei Yang Mo Cheng Jianping Shi Yanfeng Zhang The Institute for Advanced Studies Wuhan UniversityWuhan 430072China School of Materials Science and Engineering Peking UniversityBeijing 100871China

CONSPECTUS:Among two-dimensional(2D)layered materials,metallic transition metal dichalcogenides(MTMDCs)are emerging as promising candidates in many application aspects(e.g.,electronics,spintronics,and energy related fields,etc.)in view of their ultrahigh electronic conductivities,newfangled room-temperature ferromagnetism(e.g.,VSe_(2),VTe_(2)),and excellent catalytic ***,2D TaX_(2) and VX_(2)(X=S,Se,Te)materials stand in a vital place on account of their exotic physical and chemical ***,the controlled synthesis of such materials is the premise for exploring the aforementioned properties and *** the reported preparation methods,chemical vapor deposition(CVD)is proven to be a promising approach in view of its scalability,simple operation,low cost,*** method has been employed to synthesize various 2D layered materials and heterostructures in a well-controlled ***,in view of the complicated growth mechanism and process,the CVD growth of ultrathin TaX_(2) and VX_(2) nanosheets/films remains extremely *** addition,the application explorations of 2D TaX_(2) and VX_(2) in the energy related fields and electronic devices are still in the primary *** this Account,we review the up-to-date advances regarding the CVD syntheses of 2D TaX_(2) and VX_(2)(e.g.,TaS_(2),TaSe_(2),VS_(2),VSe_(2),and VTe_(2),etc.)and air-stable MTMDCs(e.g.,PtSe2,NiTe2),as well as their multifunctional applications in the energy related fields and electronic ***,the CVD growth of TaX_(2) and VX_(2) nanosheets/films with tunable thicknesses/domain sizes and the MTMDCs/semiconducting TMDCs vertical heterostructures are systematically ***,the application explorations of CVD-synthesized 2D TaX_(2) and VX_(2) as high-performance electrode materials in electrocatalytic hydrogen evolution reaction(HER)and electronic devices are introduced,***,the CVD syntheses of 2D MTMDCs with robust envir

关键词： properties Transition mentioned

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Control of sphalerite-chalcopyrite phase transition in CdSnAs2 for n-type thermoelectrics with high power factor

arXiv

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arXiv 2024年

作者： Kishida, Shoki Okamoto, Norihiko L. Katsube, Ryoji Nagaoka, Akira Nose, Yoshitaro Department of Materials Science and Engineering Kyoto University Kyoto606-8501 Japan Institute for Materials Research Tohoku University Sendai980-8577 Japan Department of Materials Process Engineering Nagoya University Nagoya464-8603 Japan Electrical and Electronic Engineering Program University of Miyazaki Miyazaki889-2192 Japan

Practical applications of thermoelectric (TE) materials are constrained by less developments of high-performance n-type materials compared to their p-type counterparts. Chalcopyrite CdSnAs2 is a promising n-type semiconductor for thermoelectrics from its narrow bandgap around 0.2 eV and exceptionally high electron mobility of 103−104 cm2 V−1s−1. In this study, we investigated the crystal growth, microstructure, and thermoelectric properties of CdSnAs2. Contrary to conventional theory of unidirectional melt growth, CdSnAs2 samples at higher cooling rates exhibited better crystallinity, while some cracks were observed in samples cooled more slowly. Thermal analyses clarified that a phase transition from sphalerite to chalcopyrite occurred after solidification in the case of slow cooling, leading to dislocations and cracks due to the lattice mismatch between phases. The analysis at rapid cooling suggested that supercooling lowers the solidification temperature and produces an appropriate microstructure. Consequently, the sample grown at the highest cooling rate (7.6 ∘C min−1) achieved an ultrahigh power factor of 3180 μW m−1K−2 at 600 K and a peak zT of 0.62 at 682 K. In the power factor, CdSnAs2 surpasses conventional binary n-type TE materials such as SnSe and PbTe, proving that CdSnAs2 is a high potential candidate for mid-temperature TE applications. © 2024, CC BY-NC-ND.

关键词： Lattice mismatch

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A coordination cage hosting ultrafine and highly catalytically active gold nanoparticles

引用

Chemical science 2022年第2期13卷 461-468页

作者： Hang, Xinxin Wang, Shentang Pang, Huan Xu, Qiang School of Chemistry and Chemical Engineering Institute for Innovative Materials and Energy Yangzhou University Yangzhou 225002 China School of Chemistry and Chemical Engineering Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function Manufacturing Southwest University Chongqing 400715 China Department of Materials Science and Engineering SUSTech Academy for Advanced Interdisciplinary Studies Southern University of Science and Technology (SUSTech) Shenzhen 518055 China Institute for Integrated Cell-Material Sciences (ICeMS) Kyoto University Yoshida Sakyo-ku Kyoto 606-8501 Japan

Ultrafine metal nanoparticles (MNPs) with size <2 nm are of great interest due to their superior catalytic capabilities. Herein, we report the size-controlled synthesis of gold nanoparticles (Au NPs) by using a thiacalixarene-based coordination cage CIAC-108 as a confined host or stabilizer. The Au NPs encapsulated within the cavity of CIAC-108 (Au@CIAC-108) show smaller size (∼1.3 nm) than the ones (∼4.7 nm) anchored on the surface of CIAC-108 (Au/CIAC-108). The cage-embedded Au NPs can be used as a homogeneous catalyst in a mixture of methanol and dichloromethane while as a heterogeneous catalyst in methanol. The homogeneous catalyst Au@CIAC-108-homo exhibits significantly enhanced catalytic activities toward nitroarene reduction and organic dye decomposition, as compared with its larger counterpart Au/CIAC-108-homo and its heterogeneous counterpart Au@CIAC-108-hetero. More importantly, the as-prepared Au@CIAC-108-homo possesses remarkable stability and durability. © The Royal Society of Chemistry.

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Intercalated Graphene and Colloidal Quantum Dots as a novel Architecture for UV/ Vis/NIR Multispectral Photodetection

Intercalated Graphene and Colloidal Quantum Dots as a novel ...

引用

IEEE Research and Applications of Photonics In Defense Conference (RAPID)

作者： J.Y. Shang S. Ahn O. Vazquez Mena Program in Materials Science and Engineering University of California San Diego La Jolla USA Department of Nanoengineering University of California San Diego/ La Jolla USA

We present a compact hybrid architecture of intercalated graphene and PbS quantum dots with independent electrical contacts for each graphene layer that allowing for detection of different spectral bands for each grap... 详细信息

ISBN: (数字)9798350373097

ISBN: (纸本)9798350373103

关键词： Electrodes Optical interferometry Graphene Quantum dots Lead Photodetectors Photoconductivity

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Low-Dose Electron Microscopy Imaging of Electron Beam-Sensitive Crystalline materials

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Accounts of materials Research 2022年第5期3卷 552-564页

作者： Jia Lv Hui Zhang Daliang Zhang Lingmei Liu Yu Han Multi-scale Porous Materials Center Institute of Advanced Interdisciplinary Studies&School of Chemistry and Chemical EngineeringChongqing UniversityChongqing 400044P.R.China Advanced Membranes and Porous Materials Center Physical Sciences and Engineering DivisionKing Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia

As one of the most widely used characterization tools in materials science,(scanning)transmission electron microscopy((S)TEM)has the unique ability to directly image specimens with atomic *** to diffraction-based techniques,the main advantage of(S)TEM imaging is that in addition to the periodic average structures of crystalline materials,it can be used to probe nonperiodic local structures such as surfaces,interfaces,dopants,and defects,which have crucial impacts on material ***,many crystalline materials are extremely sensitive to electron beam irradiation,which can only withstand dozens(or even fewer)of electrons per square angstrom before they undergo structural *** using electron doses lower than the thresholds can in principle preserve their structures,the thus acquired images are too noisy to be ***,high-resolution imaging of the inherent structures of such electron beam-sensitive materials using(S)TEM is a longstanding *** recent years,the advances in electron detectors and image-acquisition methods have enabled high-resolution(S)TEM with ultralow electron doses,largely overcoming this challenge.A series of highly electron beam-sensitive materials that are traditionally considered impossible to be imaged with(S)TEM,including metal organic frameworks(MOFs),covalent organic frameworks(COFs),organic−inorganic hybrid halide perovskites,and supramolecular crystals,have been successfully imaged at atomic *** technological advance has greatly expanded the application range of electron *** Account focuses on our recent works pertaining to the high-resolution imaging of electron beam-sensitive materials using very low electron *** first explain that the use of direct-detection electron-counting(DDEC)cameras provides the hardware basis for successful low-dose high-resolution TEM(HRTEM).Subsequently,we introduce a suite of methods to address the challenges peculiar to low-d

关键词： Electron crystalline precise

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Exploring nonlinear Rashba effect and spin Hall conductivity in Janus MXenes W2COX (X = S, Se, Te)

arXiv

引用

arXiv 2024年

作者： Bordoloi, Arjyama Singh, Sobhit Department of Mechanical Engineering University of Rochester RochesterNY14627 United States Materials Science Program University of Rochester RochesterNY14627 United States

Rashba spin-orbit coupling (RSOC) facilitates spin manipulation without relying on an external magnetic field, opening up exciting possibilities for advanced spintronic devices. In this work, we examine the effects of crystal momentum (k) nonlinearity and anisotropy on the conventional Rashba effect, with a particular focus on their impact on the spin Hall conductivity (SHC) in a newly predicted family of 2D Janus materials, W2COX (X = S, Se, Te). Using first-principles density functional theory calculations, we confirm the dynamical and mechanical stability of the studied 2D materials. Strikingly, this materials family exhibits pronounced nonlinear Rashba spin splitting at the Γ point of Brillouin zone near the Fermi level, which cannot be adequately described by the linear-k Rashba model. Therefore, third-order momentum contributions (k3) must be incorporated into the Rashba Hamiltonian. Our analysis reveals that among the studied systems, W2COS exhibits the highest k3 contribution of −45.9 eV Å3, despite having the lowest linear Rashba constant. A detailed analysis of electronic structure reveals topological nontrivial behaviour in these 2D materials, yielding sizable SHC that is primarily governed by the nonlinear Rashba effect. Notably, these materials also exhibit large spin Hall angle (0.018-2.5), which is comparable to that of in bulk topological insulators like Bi2Se3 and Bi2Te3, and surpassing those in narrow bandgap bulk semiconductors GeTe and SnTe, as well as heavy metals such as Pt. Sizable SHC, large spin Hall angles, and the ability to tune SHC via electric fields without altering the topological properties, rooted in the crystal field splitting, underscore the potential of these materials for spintronic applications. © 2024, CC BY.

关键词： Spin Hall effect

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First-principles investigation of elastic, vibrational, and thermodynamic properties of kagome metals CsM3Te5 (M = Ti, Zr, Hf)

arXiv

引用

arXiv 2024年

作者： Wei, Yifan Bordoloi, Arjyama Chuang, Chaon-En Singh, Sobhit Department of Mechanical Engineering University of Rochester RochesterNY14627 United States Materials Science Program University of Rochester RochesterNY14627 United States

Kagome metals are a unique class of quantum materials characterized by their distinct atomic lattice arrangement, featuring interlocking triangles and expansive hexagonal voids. These lattice structures impart exotic properties, including superconductivity, interaction-driven topological many-body phenomena, and magnetism, among others. The kagome metal CsM3Te5 (where M = Ti, Zr, or Hf) exhibits both superconductivity and nontrivial topological electronic properties, offering a promising platform for exploring topological superconductivity. This study employs first-principles density functional theory calculations to systematically analyze the elastic, mechanical, vibrational, thermodynamic, and electronic properties of CsM3Te5 (M = Ti, Zr, Hf). Our calculations reveal that the studied compounds - CsTi3Te5, CsZr3Te5, and CsHf3Te5 - are ductile metals with elastic properties akin to the hexagonal Bi and Sb, with average elastic constants, including a bulk modulus of 27 GPa, a shear modulus of 11 GPa, and Young's modulus of 29 GPa. We observe peculiar dispersionless, flat, phonon branches in the vibrational spectra of these metals. Additionally, we thoroughly analyze the symmetries of the zone-center phonon eigenvectors and predict vibrational fingerprints of the Raman- and infrared-active phonon modes. The analysis of thermodynamic properties reveals the Einstein temperature for CsTi3Te5, CsZr3Te5, and CsHf3Te5 to be 66, 54, and 53 K, respectively. Our orbital-decomposed electronic structure calculations reveal significant in-plane steric interactions and multiple Dirac band crossings near the Fermi level. We further investigate the role of spin-orbit coupling effect on the studied properties. This theoretical investigation sheds light on the intriguing quantum behaviour of kagome metals. © 2024, CC BY.

关键词： Spin orbit coupling

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Solute Clustering in Polycrystals: Unveiling the Interplay of Grain Boundary Junction and Long-Range Solute Attraction Effects

SSRN

引用

SSRN 2024年

作者： Nenninger, Tara Sansoz, Frederic Department of Mechanical Engineering The University of Vermont BurlingtonVT05405 United States Materials Science Program The University of Vermont BurlingtonVT05405 United States

Spectral analysis of local atomic environments has become a powerful tool for studying solute atom segregation and interactions at grain boundaries in nanocrystalline alloys. When applied to individual grain boundaries, the spectral analysis has shown that solute-solute interaction can be either attractive or repulsive, with long-range relative attraction enhancing the likelihood for solute cluster nucleation. In this article, we combine this analysis with a new grain-boundary structure descriptor based on grain-boundary atom coordination, to investigate the impact of grain-boundary junctions on solute atom segregation in polycrystals. Specifically, we systematically characterize the nucleation tendency of solute clusters at various types of ordinary grain boundaries, triple junctions, and high-order junctions in Ag polycrystals containing either Ni or Cu solute atoms. Our findings demonstrate that the nucleation of solute clusters at grain boundaries is primarily driven by long-range relative solute attraction, rather than short-range solute-solute interactions. This effect is most pronounced near grain-boundary junctions. Our study highlights the multiscale nature of solute segregation at crystalline interfaces and provides new insights into the complex phenomena governing heterogeneous solute segregation in grain-boundary networks. © 2024, The Authors. All rights reserved.

关键词： Nanocrystalline alloys

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Inverse design of quasi-bound states in the continuum metasurface for the polarization independent enhancement of Goos-H?nchen shift

引用

science China(Physics,Mechanics & Astronomy) 2024年第12期67卷 79-86页

作者： Zuhai Ma Youzhi Shi Yu Chen Yu Xue Gan Wan Chi Zhang Hui Jing Le-Man Kuang Xinxing Zhou Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education School of Physics and ElectronicsHunan Normal UniversityChangsha 410081China International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology Engineering Technology Research Center for 2D Material Information Function Devices and Systems of Guangdong ProvinceInstitute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060China Key Laboratory of Physics and Devices in Post-Moore Era College of Hunan ProvinceChangsha 410081China Academy for Quantum Science and Technology Zhengzhou University of Light IndustryZhengzhou 450002China Institute of Interdisciplinary Studies Hunan Normal UniversityChangsha 410081China

Bound states in the continuum(BIC)have been widely researched and applied in optics due to their unique electromagnetic ***,there are still difficulties in predicting and customizing BIC *** address this issue,we design an efficient combined neural network for highly accurate prediction of quasi-bound states in the continuum(q-BIC)spectrum,as well as for the inverse design of the polarization independent enhancement of the Goos-H?nchen(GH)***,we propose a C_(4)symmetric metasurface for achieving q-BIC spectrum and providing the condition of enhanced GH *** employing a combined neural network,the intensity,position,shape,and phase of q-BIC spectrum with ultra-narrow resonance can be accurately predicted and on-demand customized,even under a small ***,we develop a screening algorithm for the q-BIC spectrum to quickly realize the polarization independent enhancement of GH *** an application,an ultra-high sensitivity refractive index sensor has been proposed,whose sensitivity can reach 2.31×10~7μm/RIU for TM polarization and 1.03×10~6μm/RIU for TE ***,this work brings new solutions for quick prediction of q-BIC spectrum and the development of flexible polarization photonic devices.

关键词： Goos-Hanchen shift bound states in the continuum deep learning

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Effects of silver doping in the structural and optical properties of hematite (α-fe2o3) synthesized via chemical precipitation method 11th

Effects of silver doping in the structural and optical prope...

引用

11th International Conference on Key engineering materials, ICKEM 2021

作者： Tan, Aldrin A. Lacuesta, Aldwin Christian T. Gili, Mon Bryan Z. Cervera, Rinlee Butch M. Materials Science and Engineering Program College of Science University of the Philippines Diliman Quezon City1101 Philippines Department of Mining Metallurgical and Materials Engineering University of the Philippines Diliman Quezon City1101 Philippines Philippine Nuclear Research Institute Department of Science and Technology Philippines

ISBN: (纸本)9783035738872

Hematite (α-Fe2O3) is a low-cost n-type semiconductor with significant absorption of visible light owing to its low bandgap energy of 2.1 eV. The wide applications of hematite in renewable energy and environmental remediation continuously entice more studies. However, the low absorbance of solar energy in the UV-range significantly limits the efficiency of many photocatalytic materials. In this study, we tried to dope α-Fe2O3 with silver via chemical precipitation method to lower the bandgap energy and widen its absorbance. The effects of doping hematite with Ag on the structure, morphology, elemental composition, and optical absorbance were determined by characterizing the samples via X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, and UV-Vis spectroscopy, respectively. It was observed from the XRD patterns that the α-Fe2O3 crystallizes in hexagonal structure with lattice parameters a = 5.0380 Å and c = 13.7720 Å for the pure α-Fe2O3. Doping with 0.1M and 0.2M AgNO3 leads to a greater value of the lattice parameters indicating successful doping. SEM images show that the hematite formed was composed of particles with irregular shapes that have sizes in the range 0.865-0.883 μm. Excess silver particles were deposited on the surface of hematite. UV-Vis spectra show that there is a red-shift in the absorption band of the Ag-doped hematite. A notable decrease in the bandgap energy of the undoped α-Fe2O3 was observed from ~2.2eV to ~2.0eV with the increase in the amount of the dopant in the hematite as determined using Tauc’s plot. © 2021 Trans Tech Publications Ltd, Switzerland.

关键词： Hematite

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