Exfoliation of large-area monolayers is important for fundamental research and technological implementation transition-metal dichalcogenides. Various techniques have been explored to increase the exfoliation yield, but little known about underlying mechanism at atomic level. Here, we demonstrate gold-assisted mechanical monolayer molybdenum disulfide, up a centimeter scale. Detailed spectroscopic, microscopic, first-principles density functional theory analyses reveal that strong van der...

Two-dimensional (2D) materials have, within just one decade, reshaped many disciplines of modern science and technology, both through intensive fundamental research early commercial applications. In this review, we will provide a comprehensive summary the properties, synthesis, characterisation, application 2D in context electrochemistry related scientific fields. Firstly, structural, electronic, optical, mechanical variety preparation characterisation techniques are presented. Secondly,...

Understanding of the electrochemical properties graphene, especially electron transfer kinetics a redox reaction between graphene surface and molecule, in comparison to graphite or other carbon-based materials, is essential for its potential energy conversion storage be realized. Here we use voltammetric determination rate three mediators, ferricyanide, hexaammineruthenium, hexachloroiridate (Fe(CN)63–, Ru(NH3)63+, IrCl62–, respectively), measure reactivity samples prepared by mechanical...

Two-dimensional crystals are promising building blocks for the new generation of energy materials due to their low volume, high surface area, and transparency. Electrochemical behavior these determines performance in applications such as storage/conversion, sensing, catalysis. Nevertheless, electrochemistry an isolated monolayer molybdenum disulfide, which is one most semiconducting crystals, has not been achieved date. We report here on photoelectrochemical properties pristine few-layer...

Gold-mediated exfoliation of MoS2 has attracted considerable interest in the recent years. A strong interaction between and Au facilitates preferential production centimeter-sized monolayer with near-unity yield provides a heterostructure system noteworthy from fundamental standpoint. However, little is known about detailed nature MoS2-Au its evolution thickness. Here, we identify specific vibrational binding energy fingerprints such using Raman X-ray photoelectron spectroscopy, which...

Weak interlayer interactions in van der Waals crystals facilitate their mechanical exfoliation to monolayer and few-layer two-dimensional materials, which often exhibit striking physical phenomena absent bulk form. Here we utilize produce a form of mineral franckeite show that the phase segregation chemical species into discrete layers at sub-nanometre scale facilitates franckeite's layered structure basal cleavage down single unit cell thickness. This behaviour is likely be common wider...

The electrochemical activity of the basal plane and edge graphite has long been a subject an extensive debate. While significant advances have made, several gaps still exist in our understanding this issue, namely, relative differences perfect dependence measurable quantities on edge/defect density plane. In work, we employ microdroplet cell technique atomic force microscopy to measure localized properties graphitic surface with known coverage. electron transfer rate, capacitance, electronic...

An in situ Raman spectroelectrochemical study of Li intercalation into graphite flakes with different thicknesses ranging from 1.7 nm (3 graphene layers) to 61 (ca. 178 is presented. The lithiation behavior these was compared commercial microcrystalline a typical flake thickness ∼100 nm. the graphitic observed under potential control via optical microscopy and spectroscopy. As decreased thickness, response indicative increased tensile strain along sheet during early stages intercalation. A...

The polarizable organic/water interface is used to construct MoS2/graphene nanocomposites, and various asymmetrically dual-decorated graphene sandwiches are synthesized. High-resolution transmission electron microscopy 3D tomography confirm their structure. These graphene-based hybrids show excellent hydrogen evolution activity promising capacitance performance. Atomically thin semiconductors, monolayers of transition-metal dichalcogenides (TMDCs), increasing interest as possible substitutes...

Here, we evaluate the electrochemical performance of sparsely studied natural crystals molybdenite and graphite, which have increasingly been used for fabrication next generation monolayer molybdenum disulphide graphene energy storage devices. Heterogeneous electron transfer kinetics several redox mediators, including Fe(CN)6(3-/4-), Ru(NH3)6(3+/2+) IrCl6(2-/3-) are determined using voltammetry in a micro-droplet cell. The on both materials as function surface defectiveness, ageing, applied...

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Abstract This review delves into the intricacies of interfaces formed between two-dimensional (2D) materials and metals, exploring a realm rich with fundamental insights promising applications. Historically, our understanding 2D emanated from studies employing dielectric substrates or suspended samples. However, integrating metals in exfoliation growth processes has opened up new avenues, unveiling various shades interactions ranging dispersive forces to covalent bonding. The resulting...

A simple method for the deposition of noble metal (Pd, Au) nanoparticles on a free-standing chemical vapour deposited graphene monolayer is reported. Metal can proceed using either spontaneous or electrochemically-controlled processes. The resultant nanoclusters are characterized atomic force and electron microscopy techniques, mapping mode Raman spectroscopy.

Raman spectroscopy has become one of the most utilized methods for characterization transition metal dichalcogenides (TMDCs); however, interpretation spectra TMDC-based heterostructures been subject recent debate. Using a comprehensive combination micro-Raman and tip-enhanced spectroscopy, accompanied by ab initio simulations both frequencies intensities, we show that activation otherwise geometry-forbidden $E$ mode symmetry-forbidden ${A}_{1}$ is fingerprint strong interaction between...

CrSBr, a van der Waals material, stands out as an air-stable magnetic semiconductor with appealing intrinsic properties such crystalline anisotropy, quasi-1D electronic characteristics, layer-dependent antiferromagnetism, and non-linear optical effects. In this study, we investigate the differences between absorption emission spectra, focusing on origin of peak near 1.7 eV observed in photoluminescence spectrum CrSBr. Our findings are corroborated by excitation-dependent Raman experiments....

Abstract Gold‐assisted exfoliation (GAE) is a groundbreaking mechanical technique that produces centimeter‐scale single‐crystal monolayers of 2D materials. Such large, high‐quality films offer unparalleled advantages over the micron‐sized flakes typically produced by conventional techniques, significantly accelerating research and technological advancements in field Despite its wide applications, fundamental mechanism GAE remains poorly understood. In this study, using MoS₂ on Au as model...

CrSBr, a van der Waals material, stands out as an air-stable magnetic semiconductor with appealing intrinsic properties such crystalline anisotropy, quasi-1D electronic characteristics, layer-dependent antiferromagnetism, and non-linear optical effects....

A micro apparatus for electrochemical studies on individual high quality graphene flakes is presented. microinjection-micromanipulator system has been employed to deposit droplets of aqueous solutions containing redox-active species directly selected micro-scale areas mechanically exfoliated layers polymer coated silicon wafers. This approach allows the clear distinction between activity pristine basal planes and edges (defects) or steps be measured. Voltammetric measurements were performed...

Two-dimensional transition metal dichalcogenides are used as electroactive materials for electrochemical and electrocatalytic applications. However, it remains unclear how dichalcogenide thickness influences the response measured at its surface. We use scanning cell microscopy to assess of different thicknesses bottom-contacted MoS2, MoSe2, WS2, WSe2 towards simple outer-sphere redox couple [Ru(NH3)6]3+/2+ with submicron spatial resolution. A detailed analysis, coupling mass transport...

We show that nanometer and sub-nanometer scale defects in two-dimensional transition metal dichalcogenides can be detected electrochemically using scanning electrochemical cell microscopy (SECCM). detect isolated anomalous responses for the hexaammineruthenium ([Ru(NH3)6]3+/2+) redox couple on mono-, bi-, trilayer regions of mechanically exfoliated MoS2. These sample points display faster kinetics, with a diffusion-limited current plateau, compared to surrounding points. The analysis...

Abstract Atomically‐thin crystals have been shown to be rich in fundamental phenomena and are promising for various applications. Mechanical exfoliation of (2D) materials from bulk is particularly suited studies due the high quality resulting monolayer crystals. To date, several techniques developed increase yield, however, they still suffer drawbacks. In this work, a novel method that exploits gold‐assisted prepare large‐area monolayers layered followed by their transfer arbitrary...

Low‐dimensional carbon materials, i.e., graphene and its functionalization with a number of semiconductor or conductor such as noble metal nanostructures, have primary importance for their potential exploitation electro‐active new generation catalysts. Here, low‐cost, solution chemistry‐based, two‐step an individual, free‐standing, chemical vapor‐deposited monolayer is reported, (Au, Pt, Pd) nanoparticles to build up two‐side decorated graphene‐based nanoclusters. Either the same (symmetric...

The exfoliation of graphite to give graphene dispersions in nonaqueous solvents is an important area with regards scalable production bulk quantities and its ultimate application devices. Understanding the mechanisms governing stability these therefore both scientific interest technological importance. Herein, we have used addition indifferent electrolyte perturb few-layer a solvent (1,2-dichloroethane) as way probe importance interparticle electrostatic repulsions toward overall dispersion...