2024 2023 2022 2021 2020 ...
2024
Environmental and Thermal Stability of Chemically Exfoliated LixMoS2 for Lithium–Sulfur Batteries
Molybdenum disulfide (MoS2) can exist in the semiconducting (2H) or metallic (1T) phase. The metallic 1T phase of MoS2 is achieved by lithium intercalation using n-butyllithium. The resulting 1T MoS2 can be in a lithiated form (LixMoS2) or as pure MoS2. The 1T phase of MoS2 is metastable and relaxes to the stable 2H phase upon heating. Here we study the thermal and environmental stabilities of metallic phase LixMoS2 and pure 1T phase MoS2 for comparison. We find that the thermal stability of 1T MoS2 is enhanced by lithiation so that LixMoS2 is phase stable up to 400 °C in argon...
Z. J. Yang et al. ● 19/04/2024 ● Chemistry of Materials
Room Temperature Negative Differential Resistance with High Peak Current in MoS2/WSe2 Heterostructures
Two-dimensional transition metal dichalcogenide (2D TMD) semiconductors allow facile integration of p- and n-type materials without a lattice mismatch. Here, we demonstrate gate-tunable n- and p-type junctions based on vertical heterostructures of MoS2 and WSe2 using van der Waals (vdW) contacts. The p–n junction shows negative differential resistance (NDR) due to Fowler–Nordheim (F–N) tunneling through the triangular barrier formed by applying a global back-gate bias (VGS). We also show that the integration of hexagonal boron nitride (h-BN) as an insulating tunnel barrier between MoS2 and WSe2 leads to ...
J. H. Kim et al. ● 16/02/2024 ● ACS Nano Letters
Metal Films on Two-Dimensional Materials: van der Waals Contacts and Raman Enhancement
Electronic devices based on two-dimensional (2D) materials will need ultraclean and defect-free van der Waals (vdW) contacts with three-dimensional (3D) metals. It is therefore important to understand how vdW metal films deposit on 2D surfaces. Here, we study the growth and nucleation of vdW metal films of indium (In) and non-vdW metal films of gold (Au), deposited on 2D MoS2 and graphene. In follows a 2D growth mode in contrast to Au that follows a 3D growth mode. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to image the morphology of metal clusters during growth and quantify the nucleation density...
M. A. Ghani et al. ● 06/02/2024 ● ACS Applied Materials and Interfaces
2023
Fatigue Response of MoS2 with Controlled Introduction of Atomic Vacancies
Fatigue-induced failure resulting from repetitive stress–strain cycles is a critical concern in the development of robust and durable nanoelectromechanical devices founded on 2D semiconductors. Defects, such as vacancies and grain boundaries, inherent in scalable materials can act as stress concentrators and accelerate fatigue fracture. Here, we investigate MoS2 with controlled atomic vacancies, to elucidate its mechanical reliability and fatigue response as a function of atomic defect density...
Y. Manzanares-Negro et al. ● 16/11/2023 ● ACS Nano Lett.
Integrating 2D Materials and Plasmonics on Lithium Niobate Platforms for Pulsed Laser Operation at the Nanoscale
The current need for coherent light sources for integrated (nano)photonics motivates the search for novel laser designs emitting at technologically relevant wavelengths with high-frequency stability and low power consumption. Here, a new monolithic architecture that integrates monolayer MoS2 and chains of silver nanoparticles on a rare-earth (Nd3+) doped LiNbO3 platform is developed to demonstrate...
M. O. Ramírez et al. ● 08/11/2023 ● Laser & Photonics Rev.
Room-Temperature Photoluminescence Mediated by Sulfur Vacancies in 2D Molybdenum Disulfide
Atomic defects in monolayer transition metal dichalcogenides (TMDs) such as chalcogen vacancies significantly affect their properties. In this work, we provide a reproducible and facile strategy to rationally induce chalcogen vacancies in monolayer MoS2 by annealing at 600 °C in an argon/hydrogen (95%/5%) atmosphere. Synchrotron X-ray photoelectron spectroscopy shows that a Mo 3d5/2 core peak at 230.1 eV emerges in the annealed MoS2 associated with nonstoichiometric MoSx (0 < x < 2), and Raman spectroscopy shows an enhancement of …
Y. Zhu et al. ● 7/7/2023 ● ACS Nano
Nanoscale Cathodoluminescence and Conductive Mode Scanning Electron Microscopy of van der Waals Heterostructures
van der Waals heterostructures (vdW-HSs) integrate dissimilar materials to form complex devices. These rely on the manipulation of charges at multiple interfaces. However, at present, submicrometer variations in strain, doping, or electrical breakages may exist undetected within a device, adversely affecting macroscale performance. Here, we use conductive mode and cathodoluminescence scanning electron microscopy (CM-SEM and SEM-CL) to investigate these phenomena. As a model system, we use a monolayer WSe2 (1L-WSe2) encapsulated in …
H. Ramsden et al. ● 15/6/2023 ● ACS Nano
Lithiated metallic molybdenum disulfide nanosheets for high-performance lithium–sulfur batteries
Batteries based on redox chemistries that can store more energy than state-of-the-art lithium-ion systems will play an important role in enabling the energy transition to net zero carbon emissions. Lithium–sulfur (Li–S) batteries have shown extraordinary promise, where the electrically insulating sulfur must be loaded onto a conducting host. Here we report the use of pre-lithiated metallic 1T phase two-dimensional (2D) molybdenum disulfide (LixMoS2) as a sulfur host material for high-performance Li–S batteries under ...
Z. Li et al. ● 12/1/2023 ● Nature Energy
2022
P-type electrical contacts for two-dimensional transition metal dichalcogenides
Digital logic circuits are based on complementary pairs of n- and p-type field effect transistors (FETs) via complementary metal oxide semiconductor (CMOS) technology. In three dimensional (3D or bulk) semiconductors, substitutional doping of acceptor or donor impurities is used to achieve p- and n-type FETs. However, the controllable p-type doping of low-dimensional semiconductors such as two-dimensional transition metal dichalcogenides (2D TMDs) has proved to be challenging. Although ...
Y. Yang et al. ● 1/8/2022 ● nature
Epitaxial single-crystal hexagonal boron nitride multilayers on Ni (111)
Large-area single-crystal monolayers of two-dimensional (2D) materials such as graphene1,2,3, hexagonal boron nitride (hBN)4,5,6 and transition metal dichalcogenides7,8 have been grown. hBN is considered to be the ‘ideal’ dielectric for 2D-materials-based field-effect transistors (FETs), offering the potential for extending Moore’s law9,10. Although hBN thicker than a monolayer is more desirable as substrate for 2D semiconductors11,12, highly uniform and single-crystal multilayer hBN growth ...
K. Y. Ma et al. ● 1/6/2022 ● nature
Ferroelectricity in untwisted heterobilayers of transition metal dichalcogenides
Two-dimensional materials with out-of-plane (OOP) ferroelectric and piezoelectric properties are highly desirable for the realization of ultrathin ferro- and piezoelectronic devices. We demonstrate unexpected OOP ferroelectricity and piezoelectricity in untwisted, commensurate, and epitaxial MoS2/WS2 heterobilayers synthesized by scalable one-step chemical vapor deposition. We show d33 piezoelectric constants of 1.95 to 2.09 picometers per volt that are larger than the natural OOP piezoelectric ...
L. Rogee et al. ● 26/5/2022 ● Science
Ultrahigh Pt-Mass-Activity Hydrogen Evolution Catalyst Electrodeposited from Bulk Pt
Maximizing the Pt utilization is important for the widescale implementation of Pt-based hydrogen evolution reaction (HER) electrocatalysts, owing to the scarcity of Pt. Here, three-component heterostructured HER catalysts with ultrahigh Pt mass activity in which hollow PtCu alloy nanospheres are supported on an array of WO3 on Cu foam, are reported. It has been pointed out that the use of Pt counter electrode in a three-electrode configuration in evaluating catalysts’ HER performances in ...
L. Liu et al. ● 18/2/2022 ● Advanced Functional Materials
Tanks and Truth
The core value of science is the truth. When scientists see that an equation on the blackboard is wrong, they call it out. Facts form the foundation of our professional world as the stewards of truth, so to see falsities about the war atrocities in Ukraine deliberately multiplied over and over again by Putin’s propaganda machine and other actors on the international scene is devastating. In our very recent past, the possibility of Russian tanks rolling into Ukraine seemed remote, like a scene from a surrealistic dystopian movie, but the devastating reality is now upon us ...
N. Kotov et al. ● 22/3/2022 ● ACS Nano
Smart textile lighting/display system with multifunctional fibre devices for large scale smart home and IoT applications
Smart textiles consist of discrete devices fabricated from—or incorporated onto—fibres. Despite the tremendous progress in smart textiles for lighting/display applications, a large scale approach for a smart display system with integrated multifunctional devices in traditional textile platforms has yet to be demonstrated. Here we report ...
H. Choi et al. ● 10/2/2022 ● Nature Communications
2021
3.4% Solar-to-Ammonia Efficiency from Nitrate Using Fe Single Atomic Catalyst Supported on MoS2 Nanosheets
Electrochemical synthesis of NH3 is a carbon-free alternative to the traditional Haber–Bosch process. Obtaining NH3 from environmental pollutants, such as nitrates or nitrites, is a more practical route than from the nitrogen reduction reaction (NRR) due to the difficult cleavage of the inert triple bond of nitrogen gas. Here, a novel heterogeneous catalyst is reported based on iron (Fe) single-atoms supported on 2D MoS2 (Fe-MoS2) for the nitrate reduction reaction (NO3RR). Fe-MoS2 exhibits ...
J. Li et al. ● 22/12/2021 ● Advanced Functional Materials
Recent Advances in Design of Electrocatalysts for High‐Current‐Density Water Splitting
Electrochemical water splitting technology for producing “green hydrogen” is important for the global mission of carbon neutrality. Electrocatalysts with decent performance at high current densities play a central role in the industrial implementation of this technology. This field has advanced immensely in recent years, as witnessed by many types of catalysts designed and synthesized toward industrially-relevant current densities (> 200 mA cm–2). By discussing recent advances in ...
Y. Luo et al. ● 4/12/2021 ● Advanced Materials
Making clean electrical contacts on 2D transition metal dichalcogenides
2D semiconductors, particularly transition metal dichalcogenides (TMDs), have emerged as highly promising for new electronic technologies. However, a key challenge in fabricating devices out of 2D semiconductors is the need for ultra-clean contacts with resistances approaching the quantum limit. The lack of high-quality, low-contact-resistance P-type and N-type contacts on 2D TMDs has limited progress towards the next generation of low-power devices, such as the tunnel field-effect transistors ...
Y. Wang et al. ● 3/12/2021 ● Nature Review Physics, Pages 1-12
Stabilizing Lithium Anode Via Separator Engineering and in-Situ Electrolyte Additive Tuned SEI
Li metal anode is regarded as one of the rising stars in secondary batteries systems. Safety issues attributing from lithium dendrites, however, greatly hinders its practical application. Here we present an effective and scalable way of protecting lithium metal anode via separator engineering, and further through the tuning of solid electrolyte interface (SEI) via Li+/functional group bonding. The novel separator exhibits much higher specific surface area (~16.9x) and enhanced ionic conductivity (~3.25x) than ...
M. Fei et al. ● 10/10/2021 ● The Electrochemical Society Meeting Abstracts, Volume MA2021-02, 1903
2021 roadmap on lithium sulfur batteries
Batteries that extend performance beyond the intrinsic limits of Li-ion batteries are among the most important developments required to continue the revolution promised by electrochemical devices. Of these next-generation batteries, lithium sulfur (Li–S) chemistry is among the most commercially mature, with cells offering a substantial increase in gravimetric energy density, reduced costs and improved safety prospects. However, there remain outstanding issues to advance ...
J. B. Robinson et al. ● 23/3/2021 ● Journal of Physics: Energy, Volume 3, Number 3
Reply to: On the measured dielectric constant of amorphous boron nitride
In the accompanying Comment1, Li and Chen state that the dielectric constant (κ) values we reported for amorphous boron nitride (a-BN)2 are underestimated and are inconsistent with principles of dielectric physics. Here we show that the claims of Li and Chen are incorrect, using our original data and new data that support our initial results ...
S. Hong et al. ● 3/2/2021 ● Nature, 590, E8-10
Chemical vapour deposition
Chemical vapour deposition (CVD) is a powerful technology for producing high-quality solid thin films and coatings. Although widely used in modern industries, it is continuously being developed as it is adapted to new materials. Today, CVD synthesis is being pushed to new heights with the precise manufacturing of both inorganic thin films of 2D materials and high-purity polymeric ...
L. Sun et al. ● 14/1/2021 ● Nature Review Methods Primers, 1, Article Number 5
2020
In Situ Scanning Transmission Electron Microscopy Observations of Fracture at the Atomic Scale
The formation, propagation, and structure of nanoscale cracks determine the failure mechanics of engineered materials. Herein, we have captured, with atomic resolution and in real time, unit cell-by-unit cell lattice-trapped cracking in two-dimensional (2D) rhenium disulfide (ReS2) using in situ aberration corrected scanning transmission electron microscopy (STEM). Our real time observations of atomic configurations and corresponding strain fields ...
L. Huang et al. ● 9/12/2020 ● Physical Review Letters, 125, 246102
Nitrogen and phosphorus Co-doped nanoporous carbons from phosphoprotein/silica self-assemblies for energy storage in supercapacitors
In this work, nanoporous, heteroatom-doped carbon materials with tailorable structures and excellent charge/energy storage properties are synthesized using casein (a phosphoprotein) as a precursor and silica gel as a template via a facile synthetic route. The synthesis involves carbonization and etching. In the synthesis, an appreciable amount of the N and P atoms in casein make it as dopants into the nanoporous carbons, enabling the materials to efficiently ...
V. H. Fragal et al. ● 28/11/2020 ● ChemElectroChem, Volume 3, Number 3
Near-perfect microlenses based on graphene microbubbles
Microbubbles acting as lenses are interesting for optical and photonic applications such as volumetric displays, optical resonators, integration of photonic components onto chips, high-resolution spectroscopy, lithography, and imaging. However, stable, rationally designed, and uniform microbubbles on substrates such as silicon chips are challenging because of the random nature of microbubble formation ...
H. Lin et al. ● 7/10/2020 ● Advanced Photonics, 2(5), 055001
Quantum Transport in Two-Dimensional WS2 with High-Efficiency Carrier Injection through Indium Alloy Contacts
Two-dimensional transition metal dichalcogenides (TMDCs) have properties attractive for optoelectronic and quantum applications. A crucial element for devices is the metal–semiconductor interface. However, high contact resistances have hindered progress. Quantum transport studies are scant as low-quality contacts are intractable at cryogenic temperatures. Here, temperature-dependent transfer length measurements are performed on chemical vapor deposition ...
C. S. Lau et al. ● 11/9/2020 ● ACS Nano, 14, 10, 13700-13708
Evidence of Rotational Fröhlich Coupling in Polaronic Trions
Electrons commonly couple through Fröhlich interactions with longitudinal optical phonons to form polarons. However, trions possess a finite angular momentum and should therefore couple instead to rotational optical phonons. This creates a polaronic trion whose binding energy is determined by the crystallographic orientation of the lattice. Here, we demonstrate theoretically within the Fröhlich approach and experimentally by ...
M. Trushin et al. ● 20/8/2020 ● Physical Review Letters, 125, 086803
Single atom is not alone: Metal–support interactions in single-atom catalysis
Microbubbles acting as lenses are interesting for optical and photonic applications such as volumetric displays, optical resonators, integration of photonic components onto chips, high-resolution spectroscopy, lithography, and imaging. However, stable, rationally designed, and uniform microbubbles on substrates such as silicon chips are challenging because of the random nature of microbubble formation ...
K. Qi et al. ● 2/8/2020 ● Materials Today, Volume 40, Pages 173-192
Interfacial Oxygen‐Driven Charge Localization and Plasmon Excitation in Unconventional Superconductors
Microbubbles acting as lenses are interesting for optical and photonic applications such as volumetric displays, optical resonators, integration of photonic components onto chips, high-resolution spectroscopy, lithography, and imaging. However, stable, rationally designed, and uniform microbubbles on substrates such as silicon chips are challenging because of the random nature of microbubble formation ...
C. S. Tang et al. ● 9/7/2020 ● Advanced Materials, Volume 32, Issue 30 (2000153)
Ultralow-dielectric-constant amorphous boron nitride
Microbubbles acting as lenses are interesting for optical and photonic applications such as volumetric displays, optical resonators, integration of photonic components onto chips, high-resolution spectroscopy, lithography, and imaging. However, stable, rationally designed, and uniform microbubbles on substrates such as silicon chips are challenging because of the random nature of microbubble formation ...
S. Hong et al. ● 24/6/2020 ● Nature, 582, 511-514
From bulk to molecularly thin hybrid perovskites
Microbubbles acting as lenses are interesting for optical and photonic applications such as volumetric displays, optical resonators, integration of photonic components onto chips, high-resolution spectroscopy, lithography, and imaging. However, stable, rationally designed, and uniform microbubbles on substrates such as silicon chips are challenging because of the random nature of microbubble formation ...
K.Leng et al. ● 30/3/2020 ● Nature Review Materials, 5, 482-500
Water-resistant perovskite nanodots enable robust two-photon lasing in aqueous environment
Microbubbles acting as lenses are interesting for optical and photonic applications such as volumetric displays, optical resonators, integration of photonic components onto chips, high-resolution spectroscopy, lithography, and imaging. However, stable, rationally designed, and uniform microbubbles on substrates such as silicon chips are challenging because of the random nature of microbubble formation ...
S. Li et al. ● 4/3/2020 ● Nature Communications, 11, Article Number 1192
Synthesis of Metallic Mixed 3R and 2H Nb1+xS2 Nanoflakes by Chemical Vapor Deposition
Microbubbles acting as lenses are interesting for optical and photonic applications such as volumetric displays, optical resonators, integration of photonic components onto chips, high-resolution spectroscopy, lithography, and imaging. However, stable, rationally designed, and uniform microbubbles on substrates such as silicon chips are challenging because of the random nature of microbubble formation ...
A. R. Mohmad et al. ● 23/1/2020 ● Faraday Discussions, Volume 227, 2021
@ChhowallaL
Group Drive
Request Website Update