Graphene-like Structure Research Articles

Dimension-Dependent Nonlinear Optical Properties of Stanene Nanosheets.

Stanene (Sn)-based materials, with a graphene-like hexagonal structure, are now attracting considerable interest for potential applications in photoelectricity. However, the nonlinear optical properties of stanene remain largely unexplored. In this work, we prepared different sizes of stanene by liquid phase exfoliation and differential centrifugation methods, including two-dimensional (2D) Sn nanosheets (NSs) and zero-dimensional (0D) Sn nanodots (NDs). Z-scan measurements reveal that 2D Sn NSs exhibited high saturable absorption behavior, while the 0D Sn NDs led to reverse saturable absorption. Femtosecond ultrafast transient absorption spectra revealed that the reverse saturable absorption of Sn NDs is derived from a stronger excited state absorption and faster exciton relaxation dynamics. This research expands the potential applications of stanene in laser shielding and other ultrafast photonics technologies.

Pulsed laser deposition of MoS2 thin films at different mean kinetic plasma energies

In recent years, molybdenum disulfide has become a material of great interest for research for electronic and optoelectronic applications due to its 2-dimensional graphene-like structure and its bandgap within the visible spectrum. In this work, thin films of MoS2 were grown using pulsed laser deposition on glass substrates at room temperature and at deposition pressure of 2 × 10−5 Torr. We ablated a MoS2 target obtained by compressing high-purity powders, with a Nd-YAG pulsed laser with a wavelength of 1064 nm, 6 ns pulse width, and 10 Hz repetition rate. Laser produced plasmas were diagnosed by means of the time-of-flight technique using a Langmuir planar probe, from which mean kinetic energy and density of ions were estimated. Experimental control is more reliable using plasma parameters rather than fluence. The crystalline properties of the deposits were characterized using Raman spectroscopy and X-Ray diffraction; their chemical analysis was carried out by X-ray photoelectron spectroscopy; their thickness and morphology were characterized using atomic force microscopy and scanning electron microscopy, respectively. Results are discussed as a function of mean kinetic energy variations. It was observed that as the mean kinetic energy of the plasma decreased, the crystallinity improved and the crystal size increased.

Lithium-rich manganese-based layered oxide cathode materials for lithium-ion batteries modified by MoS2 coatings with two-dimensional graphene-like structures

Lithium-rich manganese-based layered oxide cathode materials (LRMCs) have some unique advantages such as high theoretical capacity (≥ 250 mAh g−1) and high energy density. Therefore, they are deemed as a kind of cathode material for lithium-ion batteries with an excellent prospect of application. However, the redox of oxygen anion is able to generate irreversible lattice oxygen loss, leading to irreversible loss of capacity, bringing about a sharp drop of working voltage, and seriously restricting the commercialization of LRMCs. In this paper, MoS2 coating with two-dimensional graphene-like structure was coated on the surface of LRMCs materials for improving the cycling stability and rate performance. The MoS2 coating can provide a two-dimensional diffusion channel for the migration of lithium-ions, which facilitates the fast release of lithium-ions during cycling process. The results show that the first discharge capacity, initial Coulomb efficiency and rate performance of LRMCs are improved. When the current density is 1 C, the first discharge specific capacity of LRMCs@MoS2 reaches 227.69 mAh g−1, and the capacity retention ratio is 84.98 % after 100 cycles. When the current density is 5 C, it can still provide a discharge specific capacity of 137.87 mAh g−1, demonstrating excellent electrochemical performance. This study comes up a simple and practical idea to realize the modification of cathode materials for high performance lithium-ion batteries.

Mechanistic Insight into Ion Transport in Layered Materials for Sodium-Ion Rechargeable Batteries

As a feasible alternative to Li-ion batteries (LIBs), Na-ion batteries (SIBs) are an emerging energy storage solution for electric vehicles, electronic devices, and large grid level energy storage systems. The TMD (transition metal dichalcogenides) component MoS2 and the NASICON structured-type NaxTi2(PO4)3 are two materials of interest as next-generation SIB materials. MoS2 is a 2D layered material with a graphene-like structure that can be used as a high-capacity anode or Na-ion host material as well as an electrocatalyst. Our experiments on the Al-doped 1T phase of MoS2 on reduced graphene oxide (rGO) nanosheets support demonstrated good electrochemical performance, such as 450, 400, etc. mAh/g at current densities of 0.05, 0.1 A/g. Experiments further revealed that Na-ion intercalation supports increased interlayer distance in 1T Al-MoS2@rGO, resulting in a stable phase structure. Density functional theory (DFT)-based simulations are utilized to study the intercalation properties of Na+ ions, in addition to GITT, EIS, and CV analysis. In this study, the Na-ion diffusion mechanism for 1T Al-MoS2@rGO interface and Al-MoS2-MoS2 interlayer host structure is explored. According to the experiments, the host structure is doped with 5% Al at a specific stable site, and Na-ions are introduced to the interface and interlayer (an interlayer distance of 9.3 Å is chosen, as estimated by the experiments). The Na-ion is hopped in both structures, and activation energies (Eact) are calculated to be 57.9 kJ/mol and 40.3 kJ/mol in the 1T Al-MoS2@rGO interface at migration distances of 0-2 Å and 2-4 Å, respectively. The related Na-ion diffusion coefficients are computed using an Arrhenius type fit to be in the order of 10-13 cm2/s and 10-10 cm2/s. Similarly, the Na-ion activation energy barriers in the 1T Al-MoS2-MoS2 interlayer are estimated to be between 49.8 and 59.6 kJ/mol, with related diffusivity ranging between 10-11 and 10-13 cm2/s. The outcomes of the DFT simulations are consistent with those of our experiments. The Na-ion transport properties in the NaTi2(PO4)3 bulk structure via the Na-ion vacancy assisted mechanism are investigated using MD simulations and DFT. The self-diffusion coefficients (DNa+) of bulk are examined, and then the lattice strain effect is proposed to alter its transport properties by introducing the lattice strain in uniaxial (x, y, z) and biaxial (xy, xz, yz) directions, and the changes are compared for strained and unstrained structure. In comparison to the unstrained structure at 323K, a significant improvement by 1-2 order change in DNa+ values (10-8 cm2/s - 10-10 cm2/s) is measured. DFT is also used to investigate the diffusion mechanisms along the various planes (line [001], [100], and [010]) of the bulk NaTi2(PO4)3 structure and Eact is determined along those directions, respectively. The values obtained are consistent with the experimental value ranges obtained for similar materials. In addition, a mixed ion-system is represented by inserting Li-ions at the surface of a NaTi2(PO4)3 structure, yielding the formula LixNay-xTi2(PO4)3. The sluggish kinetics of Li-ion in the NaTi2(PO4)3 structure were proposed by MD analysis. This corresponds well with experimental data that the NaTi2(PO4)3 framework exhibits preferred Na-ion insertion when cycling in mixed-ion electrolytes of varied concentrations, implying slow diffusion of Li-ions in the bulk Li+/Na+ mixed-ion crystal.

In-situ construction of ionic liquid salt-derived graphene-like dual-heteroatoms doping engineering as efficient metal-free electrocatalyst for oxygen reduction reaction

Metal-free heteroatom-doped carbon catalysts can effectively eliminate the degradation and pollution problems caused by metal dissolution. However, single heteroatom doping often restricts the regulation of geometric and electronic structures for oxygen reduction reaction (ORR) electrocatalysts. Herein, a dual atomic doping engineering to optimize the electronic structure and local coordination environment of ionic liquid salt-derived graphene-like host material as an efficient metal-free electrocatalyst for ORR. The resultant PNG catalyst with a typical nanosheets morphology with a high specific surface area and unique hierarchical porous structure. Benefiting from the uniform doping of P, N heteroatoms, graphene-like structure, optimized electronic structure and coordination environment, thus-prepared PNG-2 exhibits outstanding ORR activity, which the onset potential and half-potential are negatively shifted by around 70 mV and 46 mV, respectively, as compared to the commercial Pt/C (20 wt.%) for ORR. Furthermore, the PNG-2 exhibits the higher diffusion limiting current density, superior long-term stability as well as excellent resistance to methanol oxidation than Pt/C. Experimental studies and density functional theory (DFT) calculations reveal that the enhanced chemisorption of oxygen species (*OOH, *O and *OH) onto the P and N sites of the PNG catalysts can effectively accelerate the charge transfer kinetics and promote a favorable ORR performance.

One-pot synthesis of magnetic oil shale semi-coke nanocomposite for Fenton-like catalytic organic dye degradation: Performance and mechanism

The conversion of oil shale semi-coke (OSC) is into high-value materials has been an attractive area in waste recycling. In this study, a novel Fenton-like catalyst (Fe3O4/POSC) was successfully prepared using in-situ one-pot oxidation precipitation method for degradation of Methylene Blue (MB). The composition, morphology and properties of the materials were characterized. It was found that Fe3O4/POSC was a mesoporous material with graphene-like structure. The synergistic effect among oxygen functional groups, oxygen vacancies, unsaturated bonds and Fe2+/Fe3+ cycling in Fe3O4/POSC improved the superior degradation performance of MB. Under the optimal conditions (catalyst 1.0 g/L, pH 3.0, and H2O2 25 mmol/L), Fe3O4/POSC exhibited highly efficient degradation (92.73 % in 30 min, 99.54 % in 180 min) and stability (89.72 % after 6 cycles) of MB with low Fe leaching(<0.505 mg/L), following pseudo-first order degradation kinetics. Free radical quenching experiments showed that both •O2-/ HO2• and OH• participated in Fenton-like system, and OH• was the dominant species in MB degradation. According the degradation products of MB by GC-MS, the possible mechanism was proposed. This paper provided a better way to solving the problem of dye wastewater through the effective application of OSC waste.

Insights into molecular and bulk mechanical properties of glassy carbon through molecular dynamics simulations and mechanical tensile testing

With increasing interest in the use of glassy carbon (GC) for a broad range of application areas, the need for developing a fundamental understanding of its mechanical properties has come to the forefront. Furthermore, recent theoretical and modeling works that highlight the synthesis of GC via the pyrolysis of polymer precursors has explored the possibilities of a revisit to the investigation of their mechanical properties at a fundamental level. Although there are isolated reports on the experimental determination of its elastic modulus, insights into the stress-strain behavior of a GC material under tension and compression obtained through simulations, either at the molecular level or for the bulk materials, are missing. This study fills the gap at the molecular level and investigates the mechanical properties of GC using molecular dynamics (MD) simulations, which model the atomistic-level formation and breaking of bonds using bond-order-based reactive force field formulations. The molecular model considered in this simulation has a characteristic 3D cage-like structure of five-, six-, and seven-membered carbon rings and graphitic domains of a flat graphene-like structure. The GC molecular model was subjected to loading under varying strain rates (0.4, 0.6, 1.25, and 2.5 ns−1) and temperatures (300 K–800 K) in each of the three axes: x, y, and z. The simulations show that the GC nanostructure has distinct stress-strain curves under tension and compression. In tension, MD modeling predicted a mean elastic modulus of 5.71GPa for a single GC nanostructure with some dependency on the strain rate and temperature, whereas, in compression, the elastic modulus was also found to depend on the strain rate and temperature and was predicted to have a mean value of 35 GPa. To validate the simulation results and develop experimental insights into the bulk behavior, mechanical tests were conducted on dog-bone-shaped testing coupons that were subjected to uniaxial tension and loaded until failure. The GC test coupons demonstrated a bulk modulus of 17 ±2.69 GPa in tension, which compares well with those reported in the literature. However, comparing MD simulation outcomes to those of uniaxial mechanical testing reveals that the bulk modulus of GC in tension found experimentally is higher than the modulus of single GC nanostructures predicted by MD modeling, which inherently underestimates the bulk modulus. With regard to failure modes, the MD simulations predicted failure in tension accompanied by the breaking of carbon rings within the molecular structure. In contrast, the mechanical testing demonstrated that failure modes are dominated by brittle failure planes largely due to the amorphous structure of GC.

Utilization of mechanically strong and graphene-like bond structure membrane present inside the casing of the pea pod for advanced applications by template polymerisation

Utilization of mechanically strong and graphene-like bond structure membrane present inside the casing of the pea pod for advanced applications by template polymerisation

Theoretical studies on the aqueous phase and graphene heterogeneous degradation of acrylamide and acrylonitrile by HO, ClO, and BrO radicals

The newly discovered ClO• and BrO• contribute to pollutant degradation in advanced oxidation processes, while acrylamide (AM) and acrylonitrile (ACN) are always the focus of scientists concerned due to their continuous production and highly toxic effects. Moreover, various particles with a graphene-like structure are the companions of AM/ACN in dry/wet sedimentation or aqueous phase existence, which play an important role in heterogeneous oxidation. Thus, this work focuses on the reaction mechanism and environmental effect of AM/ACN with ClO•/BrO•/HO• in the water environment under the influence of graphene (GP). The results show that although the reactivity sequence of AM and ACN takes the order of with HO• > with BrO• > with ClO•, the easiest channel always occurs at the same C-position of the two reactants. The reaction rate constants (k) of AM with three radicals are 2 times larger than that with ACN, and amide groups have a better ability to activate CC bonds than cyanide groups. The existence of GP can accelerate the target reaction, and the k increased by 9–13 orders of magnitude. The toxicity assessment results show that the toxic effect of most products is lower than that of parent compounds, but the environmental risk of products from ClO•/BrO•-adducts is higher than those from HO•-adducts. The oxidative degradation process based on ClO• and BrO• deserves special attention, and the catalytic effect of GP and its derivatives on the oxidation process is non-negligible.

Wide-mode-area slow light waveguides in valley photonic crystal heterostructures

We designed slow-light waveguides with a wide mode area based on slab-type valley photonic crystal (VPhC) heterostructures which are composed of a graphene-like PhC sandwiched by two topologically distinct VPhCs. The group velocity of the topological guided mode hosted in a VPhC heterostructure can be slowed down by shifting the VPhC lattice toward the graphene-like PhC at the domain interfaces. Simultaneously, the mode width of the slow-light topological guided mode can be widened by increasing the size of the graphene-like PhC domain. We found that employing the graphene-like structure at the center domain is crucial for realizing a topological single-guided mode in such heterostructures. Furthermore, the impact of random fluctuations in air-hole size in the graphene-like domain was numerically investigated. Our simulation results demonstrate that the transmittance for the slow-light states can be kept high as far as the size fluctuation is small although it drops faster than that for fast-light states when the disorder level increases. The designed wide-mode-area slow-light waveguides are based on hole-based PhCs, offering novel on-chip applications of topological waveguides.

Some reentrant and compensation characteristics of a defective mixed-spin Ising bilayer graphene-like structure

Some reentrant and compensation characteristics of a defective mixed-spin Ising bilayer graphene-like structure

Surface modified molybdenum disulfide nanosheets for corrosion resistance improvement on polyurethane coatings

Abstract Organic–inorganic hybrid coating has been applied on metallic corrosion protection effectively. Molybdenum disulfide (MoS2) nanosheets with graphene-like two-dimensional lamellar structure were an anticorrosion inorganic additive, rendering the organic coating better corrosion resistant. However, the aggregation and poor solubility are still current issues that should be addressed. Functionalization MoS2 nanosheets with surface modified by polydopamine (PDA) and silane coupling agent (KH560) were prepared in polyurethane (PU) composite coatings to obtain dense and intact multilayer network structure coatings for corrosion protection. KH560-PDA-MoS2/PU coating with crosslinked polymer network structure has a high impedance modulus, large contact angle, and strong hydrophobicity. The coating meets the national technical standards for salt spray testing and nitric acid (HNO3) titration testing, demonstrating excellent corrosion resistance.

Novel structure and excellent nonlinear optical performance nanocomposite derived from flower-like MOF grown on MoS2

Molybdenum disulfide (MoS2) is a nonlinear optical material with graphene-like structure. In order to further improve the nonlinear optical performance of MoS2 and expand the application fields of MoS2, we report a simple in-situ self-growth method to functionalize MoS2 nanosheets with metal-organic framework (MOF) for the first time to pursuit excellent reverse saturable absorption performance and optical limiting performance. Firstly, defective MoS2 nanosheets was obtained by chemical etching with H2O2 and cysteamine was inserted into the sulfur vacancies under ultrasound to obtain MoS2–NH2. Then 5,10,15,20-Tetra (4-carbomethoxyphenyl) porphyrin (TCPP) as MOF active growth sites were grafted on MoS2–NH2 by amido linkage to obtain MoS2-TCPP in mild conditions. Finally, flower-like porphyrin-based CuMOF was grown on MoS2-TCPP by solvothermal method to obtain MoS2-CuMOF with stable structure. The third order nonlinear optical performance of MoS2-CuMOF were studied by Z-scan technique. It was found that the third order nonlinear absorption coefficient of MoS2-CuMOF was significantly improved compared with MoS2. Under the same energy of laser irradiation, the third order nonlinear absorption coefficient of MoS2-CuMOF nanocomposite in solution was 6 × 10−10 m/W about 2.3 times of the pristine MoS2 (2.6 × 10−10 m/W). After blending the above materials with polymethyl methacrylate (PMMA) to prepare a solid device, the third order nonlinear absorption coefficient of MoS2-CuMOF/PMMA was 18 × 10−10 m/W about 3.6 times of the MoS2/PMMA (5 × 10−10 m/W). And MoS2-CuMOF/PMMA had better optical limiting ability than MoS2/PMMA. The significant improvement in the performance of the composites can be attributed to the energy transfer between MoS2 and CuMOF, and porphyrin aggregation was inhibited by PMMA after the preparation of devices. Energy transfer can be proved by fluorescence spectroscopy. This work not only provided an example for the covalent functionalization of MoS2, but also offered a new method for designing materials with excellent nonlinear optical performance.

Unleashing the potential of Boratrane and Silatrane: A game-changing approach for enhanced boron- and silicon- incorporation in phenol-formaldehyde resins and their thermal stability

In this study, we present an innovative and cost-effective method for the preparation of phenolic resin (PR) containing boron and silicon (BPR and BSiPR) using boratrane and silatrane. Through a one-pot synthesis via a sol-gel process, 3BPR and 3B5SiPR are successfully synthesized, utilizing boratrane and silatrane as the sources of boron and silicon. Our results demonstrate the effective introduction of boron and silicon elements into the PR matrix through the formation of BO4 (borate) and SiO4 (silicate) structures, as evidenced by Cph-O-B and B-O-Si linkages. Notably, the utilization of boratrane in the synthesis of 3BPR leads to the formation of a uniform structure of BO4, as confirmed by 11B-NMR analysis. Furthermore, the resulting resins exhibit an improved char yield of 72 % at 900 °C. The formation of borate and silicate species effectively reduces the content of phenolic hydroxyl groups, thus contributing to a decrease in weight loss during the carbonization process. Additionally, the migration of boron and silicon into the carbon structure promotes the formation of B4C and B8C crystal structures, resulting in the carbonization of resins and the formation of a graphene-like structure, as confirmed by Raman spectroscopy, which exhibits a broad 2D-band. The obtained carbon materials possess both Lewis acid and basic sites. The presence of Lewis acid sites was characterized through pyridine-adsorbed FTIR, while the Lewis basic sites and CO2 absorption were examined via TPD-CO2 analysis. The CO2 absorption capacities of 3BPR and 3B5SiPR were found to be 0.475 and 0.518 mmol/g, respectively.

Green in situ synthesis of sandwich-like W-bridged siligraphene (g-SiC@WC@g-SiC) heterostructure from Saccharum Ravennae gum for ultrahigh-rate photodegradation of acetaminophen

Herein, the sandwich-like W-bridged siligraphene (W/g-SiC) as a heterojunction of WC and siligraphene nanosheets have been first accomplished via a simple green synthesis using Saccharum Ravennae gum as a natural Si and W sources and gelatin as a natural C and N sources. In a magnesiothermic process, Si and C atoms bond together and form a graphene-like structure where half of the C atoms are replaced by Si atoms. The presence of W in the natural precursor creates a W-doped siligraphene structure. Tungsten in the form of carbide (WC) creates a heterojunction with g-SiC, which reduces the bandgap. According to the experimental and computational data, the proposed structure of W/g-SiC was predicted by replacing the W atoms with Si atoms and bonding with C atoms in the siligraphene structure. The W–C bond in this structure is elongated and the W atom comes out of the siligraphene sheet and is placed between two siligraphene layers to interact with three carbons from the next layer. Under visible light irradiation, holes are generated on the g-SiC layers and electrons in the WC interlayer, which makes it a highly efficient photocatalyst with ultrafast charge separation and active surface for the removal of Acetaminophen.

Novel graphene-like layer-by-layer stacked carbon nanotube-supported Fe-Ni alloy for oxygen evolution and oxygen reduction reactions

In this study, we prepared a novel graphene-like stacked carbon nanotube-supported Fe-Ni alloy nanometer composite material. The cubic structure of nickel dimethylglyoxime was synthesized as the base material. Under hydrothermal condition, FePc was adsorbed on the surface of the nickel dimethylglyoxime cube. In addition, hydrogen peroxide not only decomposes FePc into Pc and Fe2+, but also reduces Fe2+ to Fe. On the other hand, hydrogen peroxide was first found could decompose and peel the cube of nickel dimethylglyoxime into a novel type of nanotubes with graphene-like nanosheet stacking structure. After the final calcination, the Fe2+ and Ni2+ were converted to FeNi alloy, and the dimethylglyoxime carrier with its loaded Pc was converted to carbon material. The novel structure has a large BET, which is conducive to electron transport, product transport and provides a large active site for Fe-Ni3 alloy. The composite has high electro-catalysis performance for OER and ORR, which provides a new idea for the study of new energy reserves, energy conversion and reserve materials. This study provides a new idea for preparing novel carbon nanotube-loaded transition metal composites in the field of electrocatalysis.

Potential of green-based microporous carbon for advanced water decontamination from azo dyes: Experiment and molecular dynamic simulation studies

Due to severe limitations in clean water resources, there has been an intensified focus on developing cost-effective, remarkably efficient, and recyclable adsorbents to enhance water quality. In this work, a cost-effective biobased activated carbon (AC) adsorbent was synthesized from date palm bark wastes and applied for the removal of two azo dye pollutants sunset yellow (SY), and tartrazine (TZ) from wastewater. The as-prepared powder of activated carbon was fully characterized using different analytical techniques including XRD, FTIR, XPS, Raman spectroscopy, zeta potential, FESEM, pHPZC and N2 adsorption-desorption analysis. These analyses revealed that the resulting biobased AC exhibited a graphene-like layered structure with a noticeable degree of structural order, decorated with diverse surface functional groups. The highly porous structure also demonstrated significant adsorption capacity for SY, and TZ contaminants, particularly at ambient temperatures. It achieved maximum uptakes of approximately 90 mg/g, and 65 mg/g for SY, and TZ respectively, spanning a wide pH range. Moreover, in-depth studies of the adsorption process, including kinetic and thermodynamic analyses, unveiled a chemical, spontaneous, and endothermic sorption mechanism for both SY, and TZ dyes, following a pseudo-second-order model adsorption behavior on the AC structure. Finally, an accurate adsorption mechanism has been proposed for the adsorption of dyes confirmed by experiments and molecular dynamic simulations.

The thermal instability of hydrogen-substituted graphdiyne and its role in lithium-sulfur batteries.

This study reveals the role of thermal instability in hydrogen-substituted graphdiyne (HsGDY) and its impact on lithium-sulfur (Li-S) battery performance. HsGDY undergoes significant chemical and physical transformations when subjected to thermal heating, both in the presence and absence of sulfur. Our findings suggest that the structural transformation of HsGDY into a graphene-like structure is primarily responsible for enhancing sulfur trapping and reducing the polysulfide shuttle effect, rather than the previously hypothesized alkyne-sulfur chemical interactions.

Achieving highly efficient 2D SnC monolayer-based photocatalyst for water splitting via a synergistic strategy of S-scheme heterostructure construction and silicon doping.

Owing to its stable graphene-like honeycomb structure, suitable band gap, and nontoxicity, SnC monolayer (ML) has attracted increasing attention in photocatalytic applications. One pertinent obstacle inherent to SnC ML-based photocatalysts has been the high energy barrier in hydrogen evolution reaction (HER) that always requires external energy input and/or strongly acidic conditions. Herein, we propose a two-dimensional (2D) SnC/ZrS2 van der Waals heterostructure (vdWHS) for highly efficient photocatalytic water splitting using first-principles calculations. The results show that the pristine vdWHS is an S-scheme heterostructure that works in acidic conditions for water splitting owing to the high energy barrier in HER. Notably, detailed further investigations show that doping Si in the SnC ML of the vdWHS can solve this high barrier problem, leading to a high-performance low-cost photocatalyst. Our work offers a convenient strategy to solve the notorious high barrier problem in HER that often troubles the SnC ML and other 2D materials such as transition metal dichalcogenide MLs for the design and fabrication of highly efficient photocatalysts.

A wide-bandgap graphene-like structure C6BN with ultra-low dielectric constant.

This study introduces a new wide-bandgap graphene-like structure, denoted as C6BN, achieved by incorporating an eight-electron BN pair, substantially modifying its electronic properties. Utilizing extensive density functional calculations, we comprehensively analyzed the stability, electronic structure, mechanical properties, and optical-electrical characteristics of C6BN. Our investigations reveal the material's exceptional thermodynamic, mechanical, and dynamic stability. Notably, the calculated wide bandgap of 2.81 eV in C6BN, supported by analyses of energy levels, band structures, and density of states, positions it as a promising two-dimensional wide-bandgap semiconductor. Additionally, C6BN exhibits isotropic mechanical features, highlighting its inherent flexibility. Remarkably, our calculations indicate an ultra-low dielectric constant (k = 1.67) for C6BN, surpassing that of well-established third-generation semiconductors. Further exploration into the thermoelectric properties of C6BN demonstrates its promising performance, as evidenced by calculations of thermal conductivity (κ), power factor (P), and Seebeck coefficient (S). In summary, our findings underscore the significant potential of the proposed C6BN structure as a flexible two-dimensional material poised to drive future advancements in electronic and energy-related technologies.