Properties Of 2D Nanomaterials Research Articles

Deep Learning-Based Layer Identification of 2D Nanomaterials

Two-dimensional (2D) nanomaterials exhibit unique properties due to their low dimensionality, which has led to great potential for applications in biopharmaceuticals, aerospace, energy storage, mobile communications and other fields. Today, 2D nanomaterials are often prepared and exfoliated by a combination of mechanical and manual methods, which makes the production of 2D nanomaterials inefficient and prevents standardized and industrialized manufacturing. Recent breakthroughs in semantic segmentation techniques based on deep learning have enabled the accurate identification and segmentation of atomic layers of 2D nanomaterials using optical microscopy. In this study, we analyzed in detail sixteen semantic segmentation models that perform well on public datasets and apply them to the layer identification and segmentation of graphene and molybdenum disulfide. Furthermore, we improved the U2-Net† model to obtain the best overall performance, namely 2DU2-Net†. The accuracy of the 2DU2-Net† model was 99.03%, the kappa coefficient was 95.72%, the dice coefficient was 96.97%, and the average cross–merge ratio was 94.18%. Meanwhile, it also had good performance in terms of computation, number of parameters, inference speed and generalization ability. The results show that deep learning-based semantic segmentation methods can greatly improve efficiency and replace most manual operations, and different types of semantic segmentation methods can be adapted to different properties of 2D nanomaterials, thus promoting the research and application of 2D nanomaterials.

Hybrid Nanocomposites of Plasmonic Metal Nanostructures and 2D Nanomaterials for Improved Colorimetric Detection

Plasmonic phenomena and materials have been extensively investigated for a long time and gained popularity in the last few years, finding in the design of the biosensors platforms promising applications offering devices with excellent performances. Hybrid systems composed of graphene, or other 2D materials, and plasmonic metal nanostructures present extraordinary optical properties originated from the synergic connection between plasmonic optical effects and the unusual physicochemical properties of 2D materials, thus improving their application in a broad range of fields. In this work, firstly, an overview of the structures and properties of 2D nanomaterials will be provided along with the physics of surface plasmon resonance and localized surface plasmon resonance. In the second part of the work, some examples of colorimetric biosensors exploiting the outstanding properties of hybrids nanocomposites will be presented. Finally, concluding perspectives on the actual status, challenges, and future directions in plasmonic sensing biosensing will be provided. Special emphasis will be given to how this technology can be used to support digitalization and virtualization in pandemic handling.

Two-dimensional nanomaterial-based polymer composites: Fundamentals and applications

Abstract Two-dimensional (2D) nanomaterial-reinforced polymer composites exhibit superior properties and multifunctional applications. Compared to lower dimensional nanomaterials such as nanotubes and nanoparticles, 2D nanomaterials show a larger surface area. The large surface area makes 2D nanomaterials more effectively restrict the mobility of polymer chains and yields better reinforcing efficiency than the lower-dimensional nanomaterials. To gain an in-depth understanding and extend the applications of polymer composites reinforced with 2D nanomaterials, this paper reviews the progress in the fundamentals of synthesis and applications of such composites. The motivation and improvement of adding 2D nanomaterials to polymer materials are introduced first, followed by the synthesis approaches and the properties of typical 2D nanomaterials, including graphene, boron nitride nanosheet, and molybdenum disulfide nanosheet. Based on the properties of 2D nanomaterials, polymer composites reinforced with different types of 2D nanomaterials are designed for structural application, thermal dissipation application, tribological application, three-dimensional printing composite structures, and strain sensing application. Afterwards, the significance of reinforcement–matrix interaction and its improving approach are reviewed. The current progress envisions that polymer composites reinforced with 2D nanomaterials can be used in the fields of aviation and aerospace for improving radiation shielding capacity and nanomedical engineering.

(Invited) Hybridizing Fullerenes and Two-Dimensional Nanomaterials

Fullerene has a definite zero-dimensional (0D) closed-cage molecular structure composed of sp2-hybridized carbon atoms merely, enabling it as important building blocks useful for constructing supramolecular assemblies and micro/nano functional materials.[1] Upon hybridization 2D nanomaterials with fullerenes noncovalently or covalently, the physical/chemical properties of 2D nanomaterials can be tailored and in most cases improved, significantly extending their functionalities and applications.[2] Recently, we succeeded in synthesizing several novel fullerene-2D nanomaterial hybrids via both covalent and noncovalently approaches, including graphene,[3] g-C3N4,[4] black phosphorus,[5] and MoS2,[6] and achieved enhanced photo/electrocatalytic activities.

Hybrids of Fullerenes and 2D Nanomaterials.

Fullerene has a definite 0D closed‐cage molecular structure composed of merely sp2‐hybridized carbon atoms, enabling it to serve as an important building block that is useful for constructing supramolecular assemblies and micro/nanofunctional materials. Conversely, graphene has a 2D layered structure, possessing an exceptionally large specific surface area and high carrier mobility. Likewise, other emerging graphene‐analogous 2D nanomaterials, such as graphitic carbon nitride (g‐C3N4), transition‐metal dichalcogenides (TMDs), hexagonal boron nitride (h‐BN), and black phosphorus (BP), show unique electronic, physical, and chemical properties, which, however, exist only in the form of a monolayer and are typically anisotropic, limiting their applications. Upon hybridization with fullerenes, noncovalently or covalently, the physical/chemical properties of 2D nanomaterials can be tailored and, in most cases, improved, significantly extending their functionalities and applications. Here, an exhaustive review of all types of hybrids of fullerenes and 2D nanomaterials, such as graphene, g‐C3N4, TMDs, h‐BN, and BP, including their preparations, structures, properties, and applications, is presented. Finally, the prospects of fullerene‐2D nanomaterial hybrids, especially the opportunity of creating unknown functional materials by means of hybridization, are envisioned.

Strategies for improving the lithium-storage performance of 2D nanomaterials

Abstract 2D nanomaterials, including graphene, transition metal oxide (TMO) nanosheets, transition metal dichalcogenide (TMD) nanosheets, etc., have offered an appealing and unprecedented opportunity for the development of high-performance electrode materials for lithium-ion batteries (LIBs). Although significant progress has been made on 2D nanomaterials for LIB applications in the recent years, some major challenges still exist for the direct use of these sheet-like nanomaterials, such as their serious self-agglomerating tendency during electrode fabrication and low conductivity as well as the large volume changes over repeated charging–discharging cycles for most TMOs/TMDs, which have resulted in large irreversible capacity, low initial Coulombic efficiency and fast capacity fading. To address these issues, considerable progress has been made in the exploitation of 2D nanosheets for enhanced lithium storage. In this review, we intend to summarize the recent progress on the strategies for enhancing the lithium-storage performance of 2D nanomaterials, including hybridization with conductive materials, surface/edge functionalization and structural optimization. These strategies for manipulating the structures and properties of 2D nanomaterials are expected to meet the grand challenges for advanced nanomaterials in clean energy applications and thus provide access to exciting materials for achieving high-performance next-generation energy-storage devices.