Monolayer Configuration Research Articles

Evolution of [formula omitted]-spacing in clay with PEG bulk volume fraction and molecular weight: Theoretical and experimental study

In the pursuit of ensuring the sustainability of the construction sector and fortifying its resilience against climate change, scientists have dedicated significant efforts to explore new classes of innovative, affordable, and technologically advanced materials that exhibit high efficiency, thereby securing the future for generations to come. In this context, we have opted to produce clay-polymer ecosystems through the direct insertion process. The PEG2000/clay and PEG6000/clay composites underwent analysis using X-ray diffraction (XRD) techniques, revealing the evolution of dhklconcerning the PEG bulk volume fraction. The results indicate the presence of two adsorption cycles, each comprising three stages (dilute, two-dimensional semi-dilute, and plateau). Each cycle delineates the incorporation of a polymer layer into the interlayer spaces of clay minerals. To elucidate this adsorption process, we have proposed a model depicting PEG chain conformation in confined spaces, represented as both monolayer and bilayer configurations. The influence of PEG molecular weight is distinctly evident in the dhklevolution across various clay categories. Ultimately, the application of scaling theory to model the experimental results proves to be robust, offering a precise description of the three discussed regimes.

The kinetics of droplet wetting gas hydrate surfaces regulated by anti-agglomerant monolayers: Insights from molecular dynamics study

Anti-agglomerants (AAs) have become a promising strategy for mitigating gas hydrate risks in hydrocarbon transport systems. However, a notable limitation of AAs is their diminished effectiveness in systems with high water content. The density of the AA monolayer is a critical factor influencing the coalescence and agglomeration of hydrate particles with water droplets, but the mechanisms driving these effects remain largely unknown. In this study, molecular dynamics (MD) simulations were employed to explore the anti-wetting performance and interaction properties of Cocamide Monoethanolamine (CMEA) monolayers at varying densities on hydrate surfaces. The results indicate that in systems with low-density monolayers, CMEA molecules exhibit high degrees of freedom and increased fluctuation frequencies, allowing the water molecules of droplet to penetrate the monolayer and rapidly wet the hydrate surface. In contrast, high-density monolayer configurations show properties that hinder droplet wetting on hydrate surfaces and inhibit hydrate growth. Further investigation into the adsorption behavior of CMEA molecules on hydrate surfaces highlights the substantial impact of the solution phase on adsorption free energy, with gas-phase environments enhancing the binding strength between CMEA molecules and hydrate surfaces. These molecular insights offer valuable observations regarding the structural adaptability of AA monolayers during droplet permeation and wetting processes, providing critical information for understanding the broader interactions between anti-agglomerant molecules and hydrates.

Effects of chain-chain interaction on the configuration of short-chain alkanethiol self-assembled monolayers on a metal surface.

Surface-specific sum frequency generation vibrational spectroscopy is applied to study the molecular configuration of short-chain n-alkanethiol self-assembled monolayers (SAMs with n = 2-6) on the Au surface. For monolayers with n≥ 3, the alkanethiols are upright-oriented, with the CH3 tilt angle varying between ∼33° and ∼46° in clear even-odd dependency. The ethanethiol monolayer (n = 2) is, however, found to exhibit a distinct lying-down configuration with a larger methyl tilt angle (67°-79°) and a smaller CH2 tilt angle (56°-68°). Such a unique configurational transition from n = 2 to n≥ 3 discloses the steric effect owing to chain-chain interaction among neighboring molecules. Through density functional theory calculations, the transition is further confirmed to be energetically favorable for thiols on a defective reconstructed Au(111) surface but not on the pristine one. Our study highlights the roles of the chain-chain interaction and the substrate surface atomic structure when organizing SAMs, offering a strategic pathway for exploiting their applications.

Polar iodate BiO(IO3): A two-dimensional ultrawide-bandgap semiconductor with high carrier mobility and robust piezoelectricity

Ultrawide-bandgap (UWBG) semiconductors, surpassing GaN with a bandgap of 3.4 eV, offer distinct advantages in high-temperature, high-frequency, and radiation-resistant applications. Specifically, two-dimensional (2D) UWBG materials play a crucial role in the miniaturization of practical devices. Here, employing first-principles calculations, we explore the properties of the polar iodate BiO(IO3) in its 2D monolayer configuration, boasting a bandgap of 3.61 eV. Our calculations confirm the feasibility of deriving 2D BiO(IO3) monolayer from its bulk counterpart while retaining structural stability at room temperature. The UWBG BiO(IO3) monolayer exhibits remarkable ultraviolet absorption, mechanical flexibility, and favorable electronic transport behavior. Notably, the estimated electron mobility reaches an impressive 1353.13 cm2 V−1 s−1. Importantly, the 2D structure of BiO(IO3) displays robust in-plane piezoelectricity without the odd–even effect commonly observed in other 2D piezoelectric materials. The piezoelectric coefficients d21 and d22 of monolayer reach high values of 13.87 and 16.66 pm V−1, respectively, surpassing or closely approaching those of most well-studied 2D systems. The direct stacking configuration enables 2D BiO(IO3) materials to maintain robust piezoelectricity at different thicknesses. Charge injection simulations validate the electromechanical conversion process, aligning well with its piezoelectric properties. This suggests the promising application potential of 2D BiO(IO3) in devices such as micro-electro-mechanical systems.

Effect of adaptation functions and multilayer topology on synchronization.

This study investigates the synchronization of globally coupled Kuramoto oscillators in monolayer and multilayer configurations. The interactions are taken to be pairwise, whose strength adapts with the instantaneous synchronization order parameter. The route to synchronization is analytically investigated using the Ott-Antonsen ansatz for two broad classes of adaptation functions that capture a wide range of transition scenarios. The formulation is subsequently extended to adaptively coupled multilayer configurations, using which a wider range of transition scenarios is uncovered for a bilayer model with cross-adaptive interlayer interactions.

Layer-Dependent Sensing Performance of WS2-Based Gas Sensors.

Two-dimensional (2D) materials, such as tungsten disulfide (WS2), have attracted considerable attention for their potential in gas sensing applications, primarily due to their distinctive electrical properties and layer-dependent characteristics. This research explores the impact of the number of WS2 layers on the ability to detect gases by examining the layer-dependent sensing performance of WS2-based gas sensors. We fabricated gas sensors based on WS2 in both monolayer and multilayer configurations and methodically evaluated their response to various gases, including NO2, CO, NH3, and CH4 at room temperature and 50 degrees Celsius. In contrast to the monolayer counterpart, the multilayer WS2 sensor exhibits enhanced gas sensing performance at higher temperatures. Furthermore, a comprehensive gas monitoring system was constructed employing these WS2-based sensors, integrated with additional electronic components. To facilitate user access to data and receive alerts, sensor data were transmitted to a cloud-based platform for processing and storage. This investigation not only advances our understanding of 2D WS2-based gas sensors but also underscores the importance of layer engineering in tailoring their sensing capabilities for diverse applications. Additionally, the development of a gas monitoring system employing 2D WS2 within this study holds significant promise for future implementation in intelligent, efficient, and cost-effective sensor technologies.

Recent Strategies for the Synthesis of Phase-Pure Ultrathin 1T/1T' Transition Metal Dichalcogenide Nanosheets.

The past few decades have witnessed a notable increase in transition metal dichalcogenide (TMD) related research not only because of the large family of TMD candidates but also because of the various polytypes that arise from the monolayer configuration and layer stacking order. The peculiar physicochemical properties of TMD nanosheets enable an enormous range of applications from fundamental science to industrial technologies based on the preparation of high-quality TMDs. For polymorphic TMDs, the 1T/1T' phase is particularly intriguing because of the enriched density of states, and thus facilitates fruitful chemistry. Herein, we comprehensively discuss the most recent strategies for direct synthesis of phase-pure 1T/1T' TMD nanosheets such as mechanical exfoliation, chemical vapor deposition, wet chemical synthesis, atomic layer deposition, and more. We also review frequently adopted methods for phase engineering in TMD nanosheets ranging from chemical doping and alloying, to charge injection, and irradiation with optical or charged particle beams. Prior to the synthesis methods, we discuss the configuration of TMDs as well as the characterization tools mostly used in experiments. Finally, we discuss the current challenges and opportunities as well as emphasize the promising fields for the future development.

Inclusion/energy transfer/release of L-ascorbate in the interlayer gallery of layered yttrium hydroxide

L-ascorbate (AS, Vitamin C) was intercalated into the interlayer gallery of layered yttrium hydroxide (LYH), a representative member of the layered rare earth hydroxide series (LRHs), through an ion-exchange reaction in an aqueous solution of sodium ascorbate. Based on the expansion of the interlayer space of the resulting AS-LYH hybrid, it is suggested that AS anions vertically oriented to hydroxide layers would be arranged to form a partially interdigitated bilayer in the interlayer space of LYH with a high loading capacity and density of AS. This arrangement is different from the antiparallel monolayer configuration of AS anions that are horizontally or vertically oriented to the layer of classical layered double hydroxides (LDHs). The durability of AS against light and oxidation was sufficiently enhanced in the interlayer gallery of LYH so that no degradation occurred after exposure to simulated sunlight or heating at 60 °C for a long time. Practically no release of AS from AS-LYH was observed in a saline solution and simulated sea water, whereas a sustained release of AS occurred selectively in a phosphate buffer solution, with a release process best described by the first-order model. When LYH was doped with Tb3+ activator to give it photoluminescence ability, the UV light energy absorbed for the π → π* transition of AS was efficiently transferred to Tb3+, leading to strong green emission attributed to its 5D4 → 7F5 transition.

Variation in epibiotic bacteria on two squat lobster species of Munidopsidae.

The relationships between epibiotic bacteria on deep-sea hosts and host lifestyle factors are of particular interest in the field of deep-sea chemoautotrophic environmental adaptations. The squat lobsters Shinkaia crosnieri and Munidopsis verrilli are both dominant species in cold-seep ecosystems, and they have different distributions and feeding behaviors. These species may have evolved to have distinct epibiotic microbiota. Here, we compared the epibiotic bacterial communities on the M. verrilli carapace (MVcarapace), S. crosnieri carapace (SCcarapace), and S. crosnieri ventral plumose setae (SCsetae). The epibiotic bacteria on SCsetae were dense and diverse and had a multi-layer configuration, while those on MVcarapace and SCcarapace were sparse and had a monolayer configuration. Chemoautotrophic bacteria had the highest relative abundance in all epibiotic bacterial communities. The relative abundance of amplicon sequence variant 3 (ASV3; unknown species in order Thiotrichales), which is associated with sulfide oxidation, was significantly higher in SCsetae than MVcarapace and SCcarapace. Thiotrichales species seemed to be specifically enriched on SCsetae, potentially due to the synthetic substrate supply, adhesion preference, and host behaviors. We hypothesize that the S. crosnieri episymbionts use chemical fluxes near cold seeps more efficiently, thereby supporting the host's nutrient strategies, resulting in a different distribution of the two species of squat lobster.

Ni-doped HfSe2 monolayer as a gas scavenger toward SO2 and SOF2: a DFT study

In this work, the adsorption behavior of a monolayer of HfSe2 (Ni-HfSe2) decorated with a Ni catalyst toward the SF6 decomposed gases SO2 and SOF2 is examined using the first-principles theory. On the pure HfSe2 surface, Ni atom as the catalyst substitutes the Se atom. This theoretical work investigates the geometry configurations of Ni-HfSe2 monolayers both before and after gas adsorption, as well as the electronic properties and sensitivities. The greater performance of the Ni-HfSe2 monolayer on the SO2 molecule is implied by the simulation's calculation of the of SO2 and SOF2 gas adsorption systems as −2.21 eV and −0.68 eV, respectively. This is further verified by the DOS, BS and WF analyses. The formula predicts that the Ni-HfSe2 monolayer can detect SO2 and SOF2 with sensitivity up to −80.89% and 105.59%, respectively, at room temperature (298 K), which demonstrates the sensor's advantageous sensitivity to both gases as a chemical resistance-type sensor. It is hopeful that a Ni-HfSe2 monolayer-based gas sensor will be able to distinguish between SO2 and SOF2 in a single gas atmosphere. In conclusion, this study may promote the steady operation of the power system and provide some guidance for cutting-edge electrical engineering resistance-type sensing materials.

Electronic Structure Calculations of Static Hyper(Polarizabilities) of Substrate-Supported Group-IV and -V Elemental Monolayers.

The substrate-induced effects on the polarizability (α) and first dipole hyperpolarizability (β) of group-IV (i.e., graphene, silicene, germanene, stanene) and group-V (i.e., phosphorene, arsenene, antimonene, and bismuthene) elemental monolayer nanoflakes are investigated. Density functional theory calculations show that these monolayers are bound with varying degrees of interaction strength with the Ag(111) substrate surface. Calculated dipole moment and β values are zero for the centrosymmetric configurations of the pristine elemental monolayers. On the other hand, substrate-induced changes in the electronic densities at the interface lead to substantially enhanced values of β, making these materials attractive for applications in the next-generation photonic technologies at the nanoscale.

Determining collision efficiency in multi-bubble-particle systems in presence of turbulence

Bubble-particle collision efficiency in the existing flotation literature is determined in a single bubble-particle system assuming an ideal flow field in absence of any turbulence which does not fully represent reality of the actual flotation systems. To address this knowledge gap, in this study, we numerically computed collision efficiency in a multi-bubble-particle system (particle diameter dP = 30 µm, bubble diameter dB = 1 mm) using a two-way coupled Eulerian-Lagrangian 3D computational fluid dynamics model with different solids concentrations (0.385 %–3.080 %) at turbulence intensities (Ti = 0 %–20 %). Collision efficiency of multiple particles with a single central bubble was determined in presence of different configurations of neighbouring bubbles. Two simplified multi-bubble configurations – monolayer and multilayer comprising different number of bubbles/layer, were investigated. It was noted that side-by-side collisions in monolayer configuration did not occur because particles did not have sufficient time and kinetic energy to migrate to a surrounding bubble. On contrary, in multilayer configurations, particles traversing around a leading bubble had a chance to get entrained in the rear wake and collide with a trailing bubble which resulted in higher collision efficiency compared to monolayer configurations. Modelling showed that bulk energy dissipation rate increased with number of bubbles per layer, number of bubble layers, turbulence intensity and solids concentration. For the lowest and highest solids concentration, the optimal collision efficiency occurred at Ti = 20 %, while for the intermediate solid concentration, it occurred at Ti between 4 % and 11 %. In all cases, collision efficiency increased with the energy dissipation rate.

Progress of water desalination applications based on wettability and surface characteristics of graphene and graphene oxide: A review

Seawater desalination techniques have been continuously developed to tackle the water scarcity problems. This review article provides comprehensive discussion on the progress of water desalination applications that utilize the unique wettability and surface characteristics of graphene and graphene oxides, which are being employed as ultrafiltration membranes in either a monolayer or multilayer nanosheet configuration. The interaction of water with graphene materials and their wetting characteristics as well as the controlling factors are examined. Particularly, the designs and roles of hydrophilic and hydrophobic nanopores and nanochannels are discussed. A focus is also made on recent developments of graphene membrane with respect to water flow, salt rejection and durability.

SiC2/BP5: A pentagonal van der Waals heterostructure with tunable optoelectronic and mechanical properties

The newly discovered semiconductor two-dimension (2D) materials with unique pentagon configurations of penta-SiC2 and penta-BP5 monolayers show interesting physicochemical properties. To expand the application fields of the pentagon 2D materials, we construct the SiC2/BP5 heterostructures and investigate their electronic, mechanical, optical and transport properties based on the first-principles calculations. Our results indicate that the SiC2/BP5 heterostructure and its individual components possess flexible tunability under biaxial strain. The Young’s modulus of these systems gradually decreases with the compressive (tensile) strain increasing and the penta-BP5 exhibits negative Poisson's ratio at ε ≥ 6 %. The type-II SiC2/BP5 heterostructure with an indirect bandgap (1.260 eV) shows great potential application in photoelectric devices. The tunneling probability of the heterostructure reaches 21.17 %, promoting the carrier injection efficiency in the system. Biaxial strain and external electric field enable the type-II SiC2/BP5 semiconductor to type-I or to metal. The optical properties of the SiC2/BP5 heterostructure are a fit to its monolayers. Additionally, current–voltage curve displays that the heterostructure has small current (10−3 μA) with favorable application promising in digital integrated circuits. Our work provides a theoretical guidance for the fabrication and application of novel pentagon 2D materials.

Graphene and Nickel Nanomaterials Based Surface Plasmon Resonance (SPR) Biosensor: A Theoretical Study

An extremely sensitive surface plasmon resonance (SPR) based biosensor has been simulated in the present study using an angular interrogation technique. The large surface area of the graphene layer facilitates biomolecule absorption. The SPR biosensor is proposed in a five-layer Kretschmann configuration with a ferromagnetic material and a silver layer. The proposed SPR biosensor’s sensitivity has been significantly raised in comparison to traditional film-based SPR biosensors. By refining the proposed structure to include a ferromagnetic materials nickel and monolayer of graphene with thicknesses of 15 nm and 0.34 nm and a silver layer of 45 nm, respectively, it is possible to increase sensitivity to 266°/RIU. Furthermore, the proposed SPR sensor design has a very small FWHM, a high detection accuracy (DA), and a high-quality factor (QF). Monolayer of graphene with a fixed mono-layer Nickle configuration were found to have the highest sensitivity of 266°/RIU. Additionally, it should be noted that the proposed SPR biosensor exhibits superior performance compared to SPR sensor parameters previously recorded.

Dissolved Gas Analysis in Transformer Oil Using Ni Catalyst Decorated PtSe2 Monolayer: A DFT Study

In this paper, the first-principles theory is used to explore the adsorption behavior of Ni catalyst decorated PtSe2 (Ni-PtSe2) monolayer toward the dissolved gas in transformer oil, namely CO and C2H2. Some Ni atoms from the catalyst are trapped in the Se vacancy on the pure PtSe2 surface. The geometry configurations of Ni-PtSe2 monolayer before and after gas adsorption, the electronic property of Ni-PtSe2 monolayer upon gas adsorption, and the sensibility and recovery property of Ni-PtSe2 monolayer are explored in this theoretical work. Through the simulation, the Ead of CO and C2H2 gas adsorption systems are calculated as −1.583 eV and −1.319 eV, respectively, both identified as chemisorption and implying the stronger performance of the Ni-PtSe2 monolayer on CO molecule, which is further supported by the DOS and BS analysis. According to the formula, the sensitivity of Ni-PtSe2 monolayer towards CO and C2H2 detection can reach up to 96.74% and 99.91% at room temperature (298 K), respectively, which manifests the favorable sensing property of these gases as a chemical resistance-type sensor. Recovery behavior indicates that the Ni-PtSe2 monolayer is a satisfied gas scavenger upon the noxious gas dissolved in transformer oil, but its recovery time at room temperature is not satisfactory. To sum up, we monitor the status of the transformer to guarantee the stable operation of the power system through the Ni-PtSe2 monolayer upon the detection of CO and C2H2, which may realize related applications, and provide the basis and reference to cutting-edge research in the field of electricity in the future.

Lamellar water induced quantized interlayer spacing of nanochannels walls

The nanoscale confinement is of great important for the industrial applications of molecular sieve, desalination, and also essential in biological transport systems. Massive efforts have been devoted to the influence of restricted spaces on the properties of confined fluids. However, the situation of channel-wall is crucial but attracts less attention and remains unknown. To fundamentally understand the mechanism of channel-walls in nanoconfinement, we investigated the interaction between the counter-force of the liquid and interlamellar spacing of nanochannel walls by considering the effect of both spatial confinement and surface wettability. The results reveal that the nanochannel stables at only a few discrete spacing states when its confinement is within 1.4 nm. The quantized interlayer spacing is attributed to water molecules becoming laminated structures, and the stable states are corresponding to the monolayer, bilayer and trilayer water configurations, respectively. The results can potentially help to understand the characterized interlayers spacing of graphene oxide membrane in water. Our findings are hold great promise in design of ion filtration membrane and artificial water/ion channels.

Monte Carlo Codes for Neutron Buildup Factors

The point-kernel method is a widely used practical tool for gamma-ray shielding calculations. However, application of that method for neutron transport simulations is very limited. The accuracy of the method strongly depends on the accuracy of buildup factors used in the calculations. Buildup factors are usually obtained using appropriate computer codes, either based on discrete ordinates transport method or Monte Carlo approach. Since these codes put strong demands on computer resources, they are applied on a limited number of shielding configurations and an attempt is made to use these results and formulate an empirical expression for buildup factors estimation. Due to high physical complexity of neutron transport through shielding material it is very hard to perform parameterisation in order to establish adequate empirical formula. Existing formulas are very limited and are usually applicable to a narrow neutron energy range for few commonly used shielding materials, mostly in monolayer configuration. Recently, a new approach has been proposed for determination of gamma ray buildup factors for mono-layer, as well as multi-layer shielding configurations covering a wide gamma ray energy range. The new regression model is based on support vector machines learning technique, which has theoretical background in statistical learning theory. Development of named regression model required a large number of experimental data obtained by Monte Carlo computer code. More than 7000 Monte Carlo runs were required. Due to physical complexity neutron transport is likely to require even more experimental data in order to generate a model of reasonable accuracy. Therefore, the choice of appropriate Monte Carlo code is a very important question. One has to take into account the accuracy as well as the time required for input preparation and running the code. What also has to be considered is the possibility of the code to be incorporated in an algorithm for automated generation of experimental data. In this paper three Monte Carlo codes are analysed, namely SCALE4.4 code package (SAS3 sequence), SCALE6.0 code package (MAVRIC sequence), and MCNP5. Two simple experimental setups based on a point isotropic source in spherical and slab-like shield are modelled, and the codes are examined on previously mentioned issues. The comparison results show that each one of the examined codes has potential to be used for neutron buildup factor model generation. However, some aspects of their utilization require further analysis prior to final selection.

Application of Poly-L-Lysine for Tailoring Graphene Oxide Mediated Contact Formation between Lithium Titanium Oxide LTO Surfaces for Batteries.

When producing stable electrodes, polymeric binders are highly functional materials that are effective in dispersing lithium-based oxides such as Li4Ti5O12 (LTO) and carbon-based materials and establishing the conductivity of the multiphase composites. Nowadays, binders such as polyvinylidene fluoride (PVDF) are used, requiring dedicated recycling strategies due to their low biodegradability and use of toxic solvents to dissolve it. Better structuring of the carbon layers and a low amount of binder could reduce the number of inactive materials in the electrode. In this study, we use computational and experimental methods to explore the use of the poly amino acid poly-L-lysine (PLL) as a novel biodegradable binder that is placed directly between nanostructured LTO and reduced graphene oxide. Density functional theory (DFT) calculations allowed us to determine that the (111) surface is the most stable LTO surface exposed to lysine. We performed Kubo–Greenwood electrical conductivity (KGEC) calculations to determine the electrical conductivity values for the hybrid LTO–lysine–rGO system. We found that the presence of the lysine-based binder at the interface increased the conductivity of the interface by four-fold relative to LTO–rGO in a lysine monolayer configuration, while two-stack lysine molecules resulted in 0.3-fold (in the plane orientation) and 0.26-fold (out of plane orientation) increases. These outcomes suggest that monolayers of lysine would specifically favor the conductivity. Experimentally, the assembly of graphene oxide on poly-L-lysine-TiO2 with sputter-deposited titania as a smooth and hydrophilic model substrate was investigated using a layer-by-layer (LBL) approach to realize the required composite morphology. Characterization techniques such as X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), Kelvin probe force microscopy (KPFM), scanning electron microscopy (SEM) were used to characterize the formed layers. Our experimental results show that thin layers of rGO were assembled on the TiO2 using PLL. Furthermore, the PLL adsorbates decrease the work function difference between the rGO- and the non-rGO-coated surface and increased the specific discharge capacity of the LTO–rGO composite material. Further experimental studies are necessary to determine the influence of the PLL for aspects such as the solid electrolyte interface, dendrite formation, and crack formation.

Origin and strain tuning of charge density wave in LaTe3

We study the origin of charge density wave (CDW) in rare-earth tritelluride LaTe3 and the strain tuning effect on CDW in monolayer LaTe3 by first-principles calculations. The calculations of the electronic structure, phonon spectrum, electron susceptibility, and electron-phonon coupling (EPC) matrix show that the origin of CDW in LaTe3 is momentum-dependent EPC rather than Fermi-surface nesting. The unidirectional CDW with a wave-vector QCDW≈2/7c∗ is the most stable state. We study the biaxial strain effect on CDW in monolayer LaTe3 by evaluating the total energy, CDW-related lattice distortions, and phonon spectra. Our results show that the tensile strain can enhance CDW order, while the compressive strain can inhibit CDW order. As the CDW order is fully suppressed, superconductivity could be induced. Our study may help to clarify the mechanism of CDW in LaTe3 and find the effective tuning method of CDW in monolayer or few-layer configuration.