The disassembly of 2D vertical heterostructures (2DVHs) is successfully achieved. As a demonstration, ReS2/WS2 2DVHs is disassembled into WS2 and ReS2 via Te disassembly promoters on the basis of microscopic and spectroscopic characterizations, which gives inspiration for the modification and functionalization of 2DVHs.
In this review, the exploits in which the electron beam interactions, which are often considered negative, are explored to usefully drive a wealth of chemistry in and around graphene, importantly, with no other external stimuli. After introducing the technique, this review covers carbon phase reactions between amorphous carbon, graphene, fullerenes, carbon chains, and carbon nanotubes. It then explores different studies with clusters and nanoparticles.
2D materials with ultralarge specific surface areas offer a broad portfolio of the development of high-performance micro-supercapacitors in spite of their several critical drawbacks. Based on the approaches of phase transformation, intercalation, surface modification, material hybridization, and hierarchical structuration, 2D architectures with improved conductivity, enlarged specific surface, enhanced redox activity, and the unique synergetic effect exhibit great promise in the application of miniaturized supercapacitors.
We report, for the first time, the growth of micrometer-sized two dimensional (2D) GaN single crystals on liquid metals via a surface-confined nitridation reaction and demonstrate that the 2D GaN shows uniformly incremental lattice, unique phonon modes, blue-shifted photoluminescence emission and improved internal quantum efficiency, providing direct evidence to the previous theoretical predictions.
The emergence of liquid metal catalysts has brought a brand-new perspective in the fabrication of 2D materials. The strictly self-limited growth behavior is discovered and is robust to the growth parameter variation. And the excellent rheological properties of liquid metals allow us to explore self-assembly of the 2D materials grown on the surface. This Account aims to highlight the controllable fabrication of graphene and related 2D materials on liquid metals, including the self-limited growth, self-assembly, and sliding transfer.
Responsive materials are attracting intense interest for their critical roles in intelligent designs. Here, the smart self-adapting wettability of ReS2 under sustaining light irradiation, which breaks the stereotype that a single stimulus leads to a monotonic change in properties or structures, is presented. The additional valence electron and defects ensure ReS2 has strong gas adsorption and hydrolysis capability.
Highly efficient photocatalytic hydrogen evolution (PHE) is highly desirable for addressing the global energy crisis and environmental problems.Here, a two-electron catalytic reaction is developed by utilizing the distinct trion behavior of ReS2 and the efficient reduction of two H+ (2H+ + 2e− → H2) is realized. Such a two-electron catalytic reaction endows ReS2 with a PHE rate of 13 mmol g−1 h−1 under visible light irradiation. Meanwhile, this reaction allows the typically poor PHE efficiency of pure transition metal dichalcogenides to be overcome.
Our work achieved the spontaneous assembly of alumina nanoparticles on a liquid metal surface and further synthesized a very-large-scale graphene single-crystal array. The effective electrical field established as a result of the electrical charge of the alumina nanoparticles in the liquid metal ensures the ordered self-assembly of the alumina islands and lays the foundation for precise spatial control of graphene nucleation, leading to the formation of graphene single-crystal arrays.
Two-dimensional (2D) materials have attracted tremendous research due to their excellent properties. After acquiring the qualification for being the candidate for next-generation devices, the assembly of monomers into mass or ordered structure is also of great importance, which will determine their industrialization. This review summarizes the development status of 2D material preparation for next generation integrated circuits and gives a deep thought and prospect to its future development and challenges.
2D heterostructures, which are constructed from graphene, h-BN, transition-metal dichalcogenides, transition metal carbides and so on, have shown great potential for applications in transistor, diode, photodetector and catalysis. In the past five years, great development have been made in the controllable chemical vapor deposition growth of versatile 2D heterostructures, which leads the applications of such 2D heterostructures into a more scientific and practical level.
2D MoS2 single crystals were utilized as the host material to embed Eu3+ and energy-level splitting was achieved for tuning its photoluminescence (PL). The high anisotropy of the 2D host materials makes them distort the degenerate orbitals of the Ln ions more efficiently than the symmetrical bulk host materials. A significant red-shift of the PL peak for Eu3+ was observed. The strategy for tailoring the energy level splitting of Ln ionsprovides a new method to extend their optical properties.
Temperature-responsive materials (TRMs) can adapt to the surrounding environment in the presence of a thermal stimulus, and they have attracted considerable attention in sensors, actuators, and surface engineering. Here, an inorganic material, ReS2, possesses an unexpected temperature-responsive behavior, by means of a stable and reversible thermally induced bending. ReS2 can recover to its initial configuration when the temperature drops, which is further confirmed by the reversible wetting measurement.
Herein, demonstrated by graphene (G) and hexagonal boron nitride (h-BN) and via a sequential chemical vapor deposition method, we succeed for the first time in synthesizing 2D h-BN-G core-shell arrays (CSA), which possess extremely high uniformity in shapes, sizes and distributions. Each of the core-shell units is composed of G ring-shaped shell internally filled with h-BN circular core. In addition, we perform simulations to further explain the self-symmetrical etching growth mechanism of the h-BN-G CSA.
A facile strategy for the synthesis of high-quality monolayer HfS2 crystals by van der Waals epitaxy is reported. Ultrasensitive near-infrared phototransistors based on the HfS2 crystals exhibit an ultrahigh responsivity 3.08 × 105 A W−1, and an ultrahigh detectivity exceeding 4.01 × 1012 Jones, superior to most 2D materials-based phototransistors.
Precise control of the growth of atomically thin transition metal dichalcogenides has gained significant attention in the context of van der Waals heterostructures. Here, we report growth of vertically stacked ReS2 and WS2 monolayers using a W-Re alloy foil as a supply source of Re and W atoms.
The strong interlayer attraction between 2D nanosheets leads to face-to-face stacking rather than edge-to-edge coupling. We demonstrate, for the first time, how one can induce and control an edge-to-edge self-assembly process for 2D nanomaterials. The extremely weak van der Waals coupling and strong anisotropy of ReS2 allow us to realize an oriented self-assembly process. The aspect ratio of the resulting nanoscrolls can be well controlled.
A two-dimensional superordered structure (2DSOS) was successfully synthesized. As demonstrated by graphene, the 2DSOS was prepared via self-assembly of high-quality graphene single crystals under mutual electrostatic force between the adjacent crystals assisted by airflow-induced hydrodynamic forces at the liquid metal surface. The as-obtained 2DSOS exhibits tunable periodicity in the crystal space and outstanding uniformity in size and orientation.
The synthesis of vertical ReS2 nanowalls on 3D graphene foam (V-ReS2/3DGF) is demonstrated by a chemical vapor deposition route. The vertical nanowall structure leads to an effective exposure of active sites and enhances the lithium interaction with all of the layers. when serving as the anode material for lithium‐ion batteries, the V-ReS2/3DGF composite demonstrates excellent cycling stability at high‐current‐density owing to the weak interlayer coupling of ReS2.
The single metal atom has been proposed to be a catalyst during the growth of carbon nanotubes. Our direct in situ transmission EM observation of the restructuring of the graphene edges interacting with a Fe atom directly revealed the intermediate states: pentagon and hexagon structures. In particular, experiments and simulations show that the single Fe atom behaves differently on the graphene zigzag and armchair edges, giving insights to the growth mechanisms of various sp2 carbon structures.
A facile and scalable co-segregation method is used to grow hexagonal boron nitride (h-BN) thin films from B- and N-containing metals. By annealing the sandwiched metal substrates in vacuum, sub-monolayer h-BN flakes, monolayer h-BN films, and multilayer h-BN thin films of varying thickness are successfully prepared. This approach follows an underneath-growth mode and exhibits good thickness- and location-control.
For the CVD growth of graphene, the ultimate goal is to achieve the highest quality in the largest scale and lowest cost with a precise control of layer thickness, stacking order, and crystallinity. In this Account, we focus on our recent progresses toward the controlled surface growth of graphene and its two-dimensional (2D) hybrids via rational designs of CVD elementary processes, namely, process engineering.
Here we report the rational design of a binary metal alloy that effectively suppresses the carbon precipitation process and activates a self-limited growth mechanism for homogeneous monolayer graphene. The designed binary alloy contains an active catalyst component for carbon source decomposition and graphene growth and a black hole counterpart for trapping the dissolved carbons and forming stable metal carbides. The approach may facilitate graphene research and industrial applications.
Wrinkles are often formed on CVD-graphene in an uncontrollable way. By designing the surface morphology of growth substrate together with a suitable transfer technique, we are able to engineer the dimension, density, and orientation of wrinkles on transferred CVD-graphene. Our wrinkle engineering approach allows very easily for a massive production of graphene nanoribbon arrays with bandgap-required widths, which opens a practical pathway for large-scale integrated graphene devices.
A facile strategy to grow nitrogen-doped graphene using embedded nitrogen and carbon in metal substrate via a segregation method is reported. As doping is concurrently carried out in the segregation process of the carbon species, N atoms can be substitutionally doped into the graphene lattice. This approach allows precise control of the doping degree and location, which enables growing various heterojunctions at the desired location.
High-quality charge-transfer complex AgTCNQ nanowires have been successfully synthesized by a facile nanoelectrochemical approach utilizing carbon nanotube (CNT) electrodes. These nanowires have diameters of 30-80 nm and lengths of up to several tens of micrometers, and exhibit remarkable electrical switching bistability. The uniform and high aspect ratio nature of nanowires originates from the one‐dimensional structural feature and ultrasmall surface area of the CNTs.
