A method for designing precise boron-doped graphene based on first-principle calculation

Abstract

The application discloses a method for designing accurate boron-doped graphene based on first-principle calculation. The application adopts a bottom-up construction idea, and uses a specific precursor to construct a theoretical model of a novel two-dimensional boron-doped graphene. Then, the first-principle calculation is used to analyze the dynamic stability and the electronic structure property of the theoretical model. The results show that the phonon spectrum does not have a virtual frequency, which proves the dynamic stability of the structure. Compared with traditional heteroatomic-doped graphene, the design method of the novel boron-doped graphene satisfies the controllability of the boron element doping concentration and site, has an experimental synthesis prospect, can be applied to the design of different nano material structures, and has the application potential in the field of electrode materials and the like due to the semi-metal characteristics of the novel two-dimensional structure, thereby providing a new path for the functionalization of graphene.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbon nanomaterials, and particularly relates to a method for designing precise boron-doped graphene based on first-principle calculation. BACKGROUND

[0002] Two-dimensional materials are layered materials with a thickness of only nanometer level, and have a periodic lattice, and the electrons thereof can only move freely in two dimensions in the plane. The first preparation of two-dimensional materials was made by Novoselov et al. by a mechanical exfoliation method, and graphene was successfully prepared from graphite as a raw material. Graphene has a thickness of only one carbon atom, and is composed of honeycomb-like six-membered ring carbons. The carbon atoms are hybridized in the form of sp 2 to form a strong C-C covalent bond, and the bond angle is 120° and the bond length is Compared with the three-dimensional graphite as a raw material, the two-dimensional graphene has more excellent electrical conductivity, thermal conductivity, mechanical stability and light radiation absorption capacity. The unique performance and characteristics superior to the three-dimensional structure of graphene have stimulated a research boom of two-dimensional materials by scholars all over the world. With the continuous development and in-depth research, so far, more than 800 kinds of two-dimensional materials have been successfully prepared in experiments or theoretically discovered. These two-dimensional materials have unique structural characteristics and excellent physical and chemical properties, and can be widely used in semiconductor electronic devices, biosensors, energy storage and conversion, photoelectric catalysts and many other fields, and have been favored by researchers.

[0003] At present, two-dimensional materials encounter some difficulties in traditional synthesis and design: first, it is difficult to prepare high-quality two-dimensional materials with small thickness and large size; second, there is a lack of reasonable means to synthesize two-dimensional materials with controllable orientation and uniform chemical component distribution; finally, in order to achieve a specific function, the two-dimensional materials need to be modified. Therefore, researchers need to find a reasonable structure design method to modulate the components, shape and size of the system, in order to prepare various functional materials or explore potential new two-dimensional materials. Therefore, doping stands out. The doping of heteroatoms will affect the performance of two-dimensional materials. In recent years, numerous studies have shown that the substitution of B or N in two-dimensional carbon-based materials makes them p-type or n-type semiconductors, respectively. In addition to changing the electronic structure, doping also affects the Raman spectrum and various other properties of carbon-based materials. According to statistics, by 2023, the market size of heteroatom-doped two-dimensional carbon-based materials is expected to increase to 1.3 billion US dollars. The huge market size also promotes the research of boron-doped two-dimensional carbon-based materials.

[0004] Boron, as an electron-deficient element, possesses different electronic properties from its neighboring element, carbon. Therefore, two-dimensional boron-carbon based materials, formed by combining the two, have the potential to become novel functional materials. In recent years, through the unremitting efforts of researchers, a large number of boron-doped graphene materials with different chemical ratios have been discovered theoretically and experimentally. Many studies have shown that two-dimensional boron-doped graphene has wide applications in electrode materials, electrocatalysts, electronic devices, and other fields.

[0005] In recent years, designing novel or functionalized two-dimensional materials through engineering methods has become a research hotspot. For example, in 2016, the paper "Atomically controlled substitutional boron-doping of graphene nanoribbons" published in Nature Communications reported a boron-doped graphene nanoribbon. Predicting the structural composition and functional properties of materials through theoretical calculations can provide theoretical support and potential fabrication methods for subsequent experiments, greatly saving experimental time and costs. Currently, constructing specific functional two-dimensional materials through theoretical structural design has become an important part of the two-dimensional materials research process. Summary of the Invention

[0006] This invention provides a method for precisely designing boron-doped graphene based on first-principles calculations. Using a bottom-up approach, a theoretical model of novel two-dimensional boron-doped graphene with a stoichiometric ratio of BC6 was constructed using specific precursors. Subsequently, its kinetic stability and electronic structure properties were analyzed using first-principles calculations.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] Step S1: Construct the boron-containing precursor molecular structure using VESTA software;

[0009] Step S2: Using the molecules obtained in step S1 as precursors, construct the geometric structure of a novel boron-doped graphene (BC6).

[0010] Step S3: Use Vienna ab initio simulation package (VASP) software to perform first-principles structure optimization calculations on the boron-doped graphene constructed in step S2 to obtain a stable crystal structure, and use VESTA software to obtain the geometric configuration information of the boron-doped graphene.

[0011] Step S4: Use VASP software to perform first-principles electronic property and kinetic calculations on the structure optimized in step S3;

[0012] Step S5: Process the calculation data from step S4 to obtain the electronic structure and phonon spectrum results of boron-doped graphene, which are used to analyze the physical properties and structural stability of the novel boron-doped graphene.

[0013] Furthermore, the precursor constructed in step S1 is a 1,3-[BrB]2C6H4 molecule, which is experimentally stable.

[0014] Furthermore, the specific operation for constructing novel boron-doped graphene in step S2 is as follows: first, the halogen functional groups of the 1,3-[BrB]2C6H4 precursor are removed in a "side-by-side" manner and subjected to Ullmann polymerization, and then carbon-carbon dehydrogenation condensation is carried out in a "head-to-head" manner to form novel boron-doped graphene through the above surface chemical reaction.

[0015] Furthermore, the boron-doped graphene obtained in step S3 has boron atoms doped at fixed Lewis acid sites, thus achieving controllable boron doping of graphene.

[0016] Furthermore, in step S4, an M×N supercell is established based on a novel boron-doped graphene unit cell for dynamic calculations.

[0017] Furthermore, the specific operation of the dynamic calculation data processing in step S5 is as follows: the data is processed using Phonopy software, and then the results are imported into Origin software to draw a phonon dispersion map for determining dynamic stability.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] This invention utilizes boron-containing precursor molecules and employs a bottom-up approach to design boron-doped graphene, obtaining three novel structures (BC6, BC...). 20 -Ⅰ and BC 20 -Ⅱ), the boron doping concentration and site height are highly controllable; furthermore, based on first-principles calculations, this invention demonstrates the thermodynamic and kinetic stability of three novel boron-doped graphenes and analyzes their electronic structures. BC6 exhibits half-metallic properties and has the potential for application in nanoscale high-spin-electronic devices; BC 20 -Ⅰ and BC 20 -II exhibits metallic properties and has potential applications in electrode materials. It possesses immense promise for synthesis and application. Therefore, the novel first-principles-based design and analysis method for boron-doped graphene proposed in this invention meets the design requirements for boron-doped graphene, is applicable to various carbon nanodevices, and paves the way for the design and application of heteroatom-doped graphene. Attached Figure Description

[0020] Figure 1This represents a potential surface synthesis pathway for BC6.

[0021] Figure 2 This is the crystal structure diagram of BC6.

[0022] Figure 3 This is the phonon spectrum of BC6.

[0023] Figure 4 This is the band structure and projected density of states diagram of BC6. Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1:

[0026] Step 1: Construct the molecular structure of the 1,3-[BrB]2C6H4 precursor using VESTA software.

[0027] Step 2: Using the precursor molecules constructed in Step 1, halogen functional groups are removed through Ullmann polymerization in a "side-by-side" manner, followed by carbon-carbon dehydrogenation condensation in a "head-to-head" manner, and finally, a structure perpendicular to the graphene plane is formed. In the vacuum layer, a novel boron-doped graphene composed of twelve carbon atoms and two boron atoms, with a stoichiometric ratio of BC6, was constructed through the aforementioned potential surface chemical reactions. Figure 1 As shown.

[0028] Step 3: Use VASP software to perform first-principles structure optimization on the BC6 constructed in Step 2. During the geometric structure optimization process, the cutoff energy used for plane wave expansion is 550 eV, and the energy convergence criterion is 10. -5 eV, the convergence criterion of force is Simultaneously, a 3×3×1 K-point grid was generated using the Monkhorst-Pack method at the Γ-center. A stable crystal structure with a stoichiometric ratio of BC6 was calculated. Figure 2 As shown. The structural optimization results show that the lattice constant of the BC6 unit cell is... γ = 37.72°, 2D space group is Cmm. BC bond length is... The bond length between B atoms is

[0029] Step 4: Perform first-principles electronic property and kinetic calculations on the optimized structure from Step 3 using VASP software. An 11×11×1 K-point grid was used in all electronic structure calculations. To accurately describe the crystal structure and meet the requirements of kinetic calculations, the force convergence criterion was raised to [value missing]. The energy convergence criterion has been raised to 10.-8 eV, and expand the BC6 primitive cells into 2×2×1 supercells.

[0030] Step 5: Process the calculated data from Step 4 to obtain the phonon spectrum and electronic structure results of BC6, which are used to analyze the physical properties and structural stability of the novel boron-doped graphene. The results show that the phonon spectrum of BC6 has no imaginary frequencies, such as... Figure 3 As shown, its kinetic stability has been demonstrated. Furthermore, BC6 exhibits semi-metallic properties, such as... Figure 4 As shown, it has the potential to be applied to two-dimensional metal electrode materials.

[0031] Novel boron-doped graphene design and analysis methods based on first-principles calculations include, but are not limited to, the examples above.

[0032] The above description is merely an embodiment of the present invention and does not limit the scope of this patent. Any equivalent structures and methods made using the contents of this invention and its drawings are similarly included within the patent protection scope of this invention.

Claims

1. A first-principles-based design method for boron-doped graphene, comprising the following steps: Step S1: Construct the molecular structure of the boron-containing 1,3-[BrB]2C6H4 precursor using VESTA software; Step S2: Using the molecules obtained in step S1 as precursors, halogen functional groups are removed in a "side-by-side" manner to carry out Ullmann polymerization, and then carbon-carbon dehydrogenation condensation is carried out in a "head-to-head" manner to construct the geometric structure of boron-doped graphene (BC6). Step S3: Use Vienna ab initio simulation package (VASP) software to perform first-principles structure optimization calculations on the boron-doped graphene constructed in step S2 to obtain a stable crystal structure, and use VESTA software to obtain the geometric configuration information of the boron-doped graphene. Step S4: Use VASP software to perform first-principles electronic property and kinetic calculations on the structure optimized in step S3; Step S5: Process the calculation data from step S4 to obtain the electronic structure and phonon spectrum of boron-doped graphene, which are used to analyze the physical properties and structural stability of boron-doped graphene.

2. The method according to claim 1, characterized in that, The boron-doped graphene obtained in step S3 has boron atoms doped at fixed Lewis acid sites, thus achieving controllable boron doping of graphene.

3. The method according to claim 1, characterized in that, In step S4, an M×N supercell is established based on boron-doped graphene unit cells for dynamic calculations.

4. A boron-doped graphene based on first-principles calculations, characterized in that, It is obtained by using the design method described in claim 1.

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