A method for constructing a heterojunction electronic structure based on first-principle calculation
The electronic structure of the MXene/h-BN heterojunction was constructed by first-principles calculations, which solved the problem of synergistic optimization of electromagnetic shielding and heat dissipation of traditional materials. It enabled precise control of the heterojunction interface performance and promoted the research and development and industrialization of high-end electronic devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QINGDAO INNOVATION & DEV CENT OF HARBIN ENG UNIV
- Filing Date
- 2026-02-12
- Publication Date
- 2026-06-09
AI Technical Summary
Traditional single materials are difficult to optimize electromagnetic shielding and heat dissipation performance in a coordinated manner, and existing experimental methods are difficult to effectively control the electronic structure of heterojunction interfaces, which limits the development progress of MXene/h-BN composite materials.
The electronic structure of the MXene/h-BN heterojunction was constructed using first-principles calculations. Stable crystal structures were screened, end groups were optimized, and geometric and electronic structure calculations were performed to achieve multi-dimensional optimization of the heterojunction model.
This reduces the cost of experimental trial and error, clarifies the regulation law of electromagnetic wave loss mechanism by the electronic structure of heterojunction interface, improves electromagnetic shielding and heat dissipation performance, and promotes the precise design and industrial application of high-performance composite materials.
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Figure CN122177303A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the fields of computational materials science and functional materials design technology, specifically to a method for constructing heterojunction electronic structures based on first-principles calculations. Background Technology
[0002] With the rapid development of high-end electronic devices and communication systems towards higher density, higher integration, and higher power, developing single-function materials that can simultaneously and efficiently solve the problems of heat dissipation and electromagnetic interference has become a major core challenge that urgently needs to be overcome in the field of materials science. The core challenge lies in the fact that heat dissipation performance and electromagnetic shielding performance are often mutually restrictive and contradictory. Traditional single materials are unable to achieve synergistic optimization of the two and cannot meet the stringent requirements of high-end devices for comprehensive performance.
[0003] Two-dimensional layered materials, especially MXene and hexagonal boron nitride (h-BN), have become key research targets for solving the aforementioned challenges due to their excellent electrical, thermal, and mechanical properties endowed by their unique two-dimensional crystal structure. Among them, MXene, with its excellent metallic conductivity and two-dimensional layered structure, shows broad application potential in the field of electromagnetic shielding and is a promising candidate material for electromagnetic shielding. However, its electromagnetic shielding mechanism is mainly based on electromagnetic wave reflection, which can easily cause secondary electromagnetic pollution. Furthermore, its thermal properties are significantly affected by the type and distribution of surface end groups (such as -OH, -O, -F, etc.), making it difficult to control thermal conductivity and achieve stable optimization of heat dissipation performance. In contrast, h-BN is a novel insulating and thermally conductive material with ultra-high in-plane thermal conductivity, excellent electrical insulation, and chemical stability. It can efficiently meet the dual requirements of heat conduction and electrical insulation, but it does not possess electromagnetic shielding capabilities and cannot meet the comprehensive requirements of high-end devices for integrated electromagnetic shielding and heat dissipation.
[0004] To fully leverage the performance advantages of both materials and compensate for their respective shortcomings, experimental researchers have attempted to construct MXene / h-BN heterojunction composites to achieve a synergistic improvement in electromagnetic shielding and heat dissipation performance. However, this research path faces significant experimental trial-and-error costs and development bottlenecks: core scientific questions such as how the electronic structure at the heterojunction interface regulates its electromagnetic wave loss mechanism, the lattice dynamics stability of the heterojunction, and its thermal transport potential are difficult to fundamentally understand solely through macroscopic experimental testing. This results in material synthesis and structural design remaining in a stage of blind exploration, severely restricting the development and industrial application of high-performance composite systems. Summary of the Invention
[0005] In order to solve the above-mentioned technical problems, this application proposes the following technical solution: In a first aspect, embodiments of this application provide a method for constructing the electronic structure of a heterojunction based on first-principles calculations, including: Stable ground-state crystal structure files of Ti3AlC2 and h-BN were screened and obtained from the Materials Project crystal database to ensure that the lattice parameters and thermodynamic stability of the obtained crystal structures were experimentally verified. Constructing and optimizing Ti3C2T with different surface end groups X The MXene monolayer model was used to obtain its stable lattice constant, electronic structure, and density of states. Based on the optimized single-layer model, Ti3C2T with different end groups X A heterojunction model is constructed by combining single-layer and BNNS single-layer structures. The binding energy of the heterojunction is calculated using first-principles calculations. The geometric optimization and electronic structure calculations are then performed on the constructed heterojunction model to achieve multi-dimensional optimization of the heterojunction model.
[0006] In one possible implementation, the construction and optimization of Ti3C2T with different surface end groups... X The MXene monolayer model was used to obtain its stable lattice constant, electronic structure, and density of states, including: Ti3AlC2 was cut along a predetermined direction to obtain the initial Ti3C2 unit cell, and a 15Å vacuum layer was added. After convergence testing, the cutoff energy was determined. Functional groups (-O, -F, -OH) were added to its surface, and the structure was optimized to complete Ti3C2T. X The establishment of the MXene model.
[0007] In one possible implementation, structural optimization is performed to complete the Ti3C2T. X The establishment of the MXene model includes: Simulations based on the CASTEP quantum mechanics program using first-principles calculations were conducted to study the exchange-correlation interaction in two-dimensional Ti3C2T using the PBE functional method with the generalized gradient approximation (GGA). X MXene performs geometry optimization; The interaction between electrons and atomic nuclei and ions is described using the OTFG ultrasoft pseudopotential. To describe weak interactions such as hydrogen bonds and van der Waals interactions, Grimme in DFT-D is used for dispersion correction. The metal option and the optimize cell option are selected to release stress, the precision is set to Ultra-fine, and the convergence criterion in structure optimization is set. The Brillouin zone integral grid was generated using the Monkhorst-Pack k-point sampling method to eliminate the potential interference of the crystal's periodicity along the Z-axis on the calculation results, and a vacuum layer was introduced in the Z-axis direction.
[0008] One possible implementation also includes: constructing a BNNS structure model before constructing a heterojunction model.
[0009] In one possible implementation, constructing the BNNS structural model includes: The h-BN model imported from the Materials Project crystal database was sectioned along a set direction, and the thickness was adjusted to obtain a single-layer structure. Using the CASTEP module in MS software, add Grimme dispersion correction, uncheck "metal", check the "optimize cell" option, release stress, set the precision to "Ultra-fine", and optimize the BNNS single-layer structure by setting the convergence criteria in the structure optimization.
[0010] In one possible implementation, the optimized single-layer model is used as a basis to combine Ti3C2T with different end bases. X A heterojunction model is constructed by combining a single layer with a BNNS single layer, including: The geometric models of two crystal structures are stacked to form a rough heterojunction geometric model using the build layer function of MS software. Determining Ti3C2T based on lattice constant X MXene cell expansion and BNNS cell expansion; The expanded cell structures were optimized separately. During the heterojunction stacking process, the interlayer spacing of the MXene monolayer and the BNNS monolayer was set to the default value. The interlayer spacing was optimized to reach a thermodynamically stable value. During the optimization process, the atomic degrees of freedom within the layer were maintained, and the relative positions between the layers were constrained to avoid slippage.
[0011] In one possible implementation, the step of stacking the geometric models of two crystal structures to construct a rough heterojunction geometric model using the build layer function of MS software includes: using the build-buildlayers function of MS software, selecting the expanded MXene structure as the bottom layer in layer1 and the expanded BNNS structure as the top layer in layer2, selecting build layered structure as a crystal, and then building to establish a rough heterojunction model.
[0012] In one possible implementation, electronic structure calculations are performed on the constructed heterojunction model, including: based on the CASTEP module, selecting CASTEP calculation and retaining the parameters of geometric optimization; changing the Task to Energy, selecting Band structure and Density of states in the properties column, selecting GMKG for the Band structure path, and checking calculate PDOS for the Density of states calculation.
[0013] In this embodiment, the reliability of subsequent models is ensured by screening experimentally verified stable crystal structures. Optimization of MXene monolayers with different end groups and construction of heterojunctions, combined with first-principles calculations to achieve multi-dimensional optimization, clarifies the regulatory mechanism of electromagnetic wave loss on the heterojunction interface electronic structure, effectively suppressing secondary electromagnetic pollution caused by MXene. Simultaneously, the thermal conductivity of MXene is precisely controlled, fully leveraging the ultra-high in-plane thermal conductivity of h-BN to achieve synergistic performance improvement. This method significantly reduces experimental trial-and-error costs, propelling heterojunction composite materials from blind exploration to precise design, providing scientific support for the development of high-performance integrated heat dissipation and electromagnetic shielding materials, and contributing to the industrialization of high-end electronic devices. Attached Figure Description
[0014] Figure 1 A schematic flowchart illustrating a method for constructing a heterojunction electronic structure based on first-principles calculations, provided in this application embodiment; Figure 2 The Ti3C2T provided in the embodiments of this application X Schematic diagram of the MXene@BNNS heterojunction model; Figure 3 The Ti3C2T provided in the embodiments of this application X MXene bandgap diagram; Figure 4 The Ti3C2T provided in the embodiments of this application X Schematic diagram of MXene state density; Figure 5 The Ti3C2T provided in the embodiments of this application X MXene@BNNS can bring images; Figure 6 The Ti3C2T provided in the embodiments of this application X Schematic diagram of MXene@BNNS density of states. Detailed Implementation
[0015] The present solution will now be described in conjunction with the accompanying drawings and specific embodiments.
[0016] See Figure 1 The method for constructing the electronic structure of a heterojunction based on first-principles calculations provided in this embodiment includes: S101. Stable ground-state crystal structure files of Ti3AlC2 and h-BN were screened and obtained from the Materials Project crystal database to ensure that the lattice parameters and thermodynamic stability of the obtained crystal structures were experimentally verified.
[0017] To ensure the accuracy and reliability of subsequent heterojunction model construction and to provide a high-quality initial structural foundation for first-principles calculations, this embodiment requires the precise selection and downloading of stable ground-state crystal structure files of Ti3AlC2MAX phase material and hexagonal boron nitride (h-BN) from the authoritative Materials Project crystal database.
[0018] During the screening process, the core parameters of the two crystal structures must be rigorously verified. Special emphasis is placed on confirming that the lattice parameters (including cell edge length and cell angle) and thermodynamic stability of the obtained crystal structures have been experimentally characterized and verified. Crystal structures with lattice distortion, thermodynamic instability, or other defects that do not meet the requirements are excluded. This ensures that the selected initial crystal structure can truly reflect the intrinsic properties of Ti3AlC2 and h-BN, laying the foundation for subsequent Ti3C2T... X The MXene monolayer model construction optimization, heterojunction assembly and performance calculation provide reliable structural support, reducing subsequent calculation errors from the source and improving the scientificity and credibility of research results.
[0019] S102, Constructing and Optimizing Ti3C2T with Different Surface End Groups X The MXene single-layer model was used to obtain its stable lattice constant, electronic structure, and density of states.
[0020] The initial Ti3C2 unit cell was obtained by slicing Ti3AlC2 along the (001) direction. A 15 Å vacuum layer was added, and the cutoff energy was determined to be 700 eV after convergence testing. The k-point was 9*9*1. Functional groups (-O, -F, -OH) were added to its surface and the structure was optimized to complete Ti3C2T X The establishment of the MXene model.
[0021] Simulations based on the CASTEP quantum mechanics program using first-principles calculations were conducted to study the exchange correlation interactions using the Perdew-Burke-Ernzerhofe (PBE) functional method with the generalized gradient approximation (GGA) for two-dimensional Ti3C2T. XMXene undergoes geometry optimization. The interaction between electrons and atomic nuclei / ions is described using the OTFG ultrasoft pseudopotential to account for weak interactions such as hydrogen bonding and van der Waals interactions. The OTFG ultrasoft pseudopotential effectively handles systems containing transition metals (Ti) and light elements (B, N, O, F, H). Grimme dispersion correction is performed using DFT-D. The interface between MXene and BNNS is a van der Waals heterostructure, and its stability is primarily determined by weak interactions. Conventional first-principles calculations (such as using only PBE) severely underestimate the interlayer binding energy, leading to model distortion. This embodiment introduces Grimme dispersion correction to accurately describe the unique interface physics of this heterostructure.
[0022] Due to the metallicity of MXene, the "metal" option and the "optimize cell" option were selected to release stress. The accuracy was set to Ultra-fine, and the convergence criteria in the structural optimization were: maximum energy not exceeding 5.0e-6 eV / atom, atomic stress not exceeding 0.01 eV / A, maximum stress not exceeding 0.03 GPa, and maximum displacement not exceeding 5.0e-4 Å. A 9*9*1 k-point Brillouin zone integral grid was generated using the Monkhorst-Pack k-point sampling method. To eliminate the potential interference of the crystal's periodicity along the Z-axis on the calculation results, a 15 Å thick vacuum layer was introduced in the Z-axis direction.
[0023] S103, based on the optimized single-layer model, combines Ti3C2T with different end bases. X A heterojunction model is constructed by combining a single layer with a BNNS single layer.
[0024] The h-BN model imported from the Materials Project crystal database was truncated along the (001) direction, and the thickness was adjusted to obtain a single-layer structure. The cutoff energy was determined to be 600 eV and the k-point was 6*6*1 after convergence testing. The structure was then optimized.
[0025] Structural optimization was performed using the CASTEP module in MS software. Given the presence of interlayer van der Waals forces in the system, Grimme dispersion correction was added. Due to the insulating nature of BNNS, the "metal" option was unchecked, and the "optimize cell" option was checked to release stress. The accuracy was set to Ultra-fine. The convergence criteria for structural optimization were: maximum energy not exceeding 5.0e-6 eV / atom, atomic stress not exceeding 0.01 eV / A, maximum stress not exceeding 0.03 GPa, and maximum displacement not exceeding 5.0e-4 Å.
[0026] The geometric models of two crystal structures are stacked to create a rough heterojunction geometric model using the build layer function in MS software. Specifically, using the build-build layers function in MS software, the expanded MXene structure is selected as the bottom layer for layer 1, and the expanded BNNS structure is selected as the top layer for layer 2. Then, select "build layeredstructure as a crystal" and click "build" to create a rough heterojunction model.
[0027] Since both MXene and BNNS belong to the hexagonal crystal system, there is no need to change the lattice vectors; only cell expansion is needed to reduce the mismatch. To ensure that the lattice mismatch of the structure is less than 5%, the lattice constant of Ti3C2T is determined. X MXene was expanded to a cell size of 4*4*1, and BNNS to a cell size of 5*5*1, with an calculated η of 2.2%. The expanded structures were then optimized, resulting in k-point values of 3*3*1 and 2*2*1 respectively. During the heterojunction stacking process, the interlayer spacing between the MXene and BNNS monolayers was set to the default value. Structural optimization was used to achieve a thermodynamically stable interlayer spacing, maintaining the atomic degrees of freedom within each layer and constraining the relative positions between layers to prevent slippage. The in-plane lattice constants of the optimized BNNS and Ti3C2TX are shown in Table 1, and the constructed heterostructure model is shown in Figure 2.
[0028] Table 1. Cell parameters of the system architecture S104. The binding energy of the heterojunction is calculated using first-principles calculations. The geometric optimization and electronic structure calculations are performed on the constructed heterojunction model to achieve multi-dimensional optimization of the heterojunction model.
[0029] Based on the CASTEP module, select CASTEP calculation, retain the parameters for geometry optimization, change the Task to Energy, select Band structure and Density of states in the properties section, select GMKG for the Band structure path, and check "calculate PDOS" for the Density of states calculation.
[0030] join Figure 3 and Figure 4 (a) corresponds to BNNS, (b) corresponds to Ti3C2O2, (c) corresponds to Ti3C2F2, and (d) corresponds to Ti3C2(OH)2. From Figure 3 and 4As can be seen, BNNS exhibits typical insulating properties, with a wide bandgap of approximately 4.7 eV at the Fermi level in the band structure diagram. The valence band top and conduction band bottom show localized narrow peaks, consistent with its characteristics as an excellent insulating and thermally conductive material. Three types of Ti3C2T... X All MXenes exhibit metallic properties, with Ti3C2(OH)2 exhibiting the highest density of states, with a peak height near the Fermi level of approximately 36 states / eV. See also... Figure 5 and Figure 6 (a) corresponds to Ti3C2O2@BNNS, (b) corresponds to Ti3C2F2@BNNS, and (c) corresponds to Ti3C2(OH)2@BNNS. From Figure 5 and Figure 6 The results show that Ti3C2(OH)2@BNNS has the highest interface state density near the Fermi level, approximately 55 states / eV, with the strongest interface electronic coupling and abundant electronic transition channels. This can efficiently promote the absorption and loss of electromagnetic wave energy, overcoming the deficiency of the single MXene shielding mechanism, which is mainly based on reflection. The density of states curve of Ti3C2(OH)2@BNNS is smooth without abrupt changes, and there are no obvious scattering centers in the lattice vibrations, ensuring the efficient transmission of thermal phonons while retaining the insulating and thermally conductive properties of BNNS.
[0031] In summary, the hydroxyl end group enhances the interfacial electronic coupling between MXene and BNNS and optimizes lattice vibration characteristics. This not only effectively improves the shielding defects of MXene alone, which is mainly based on reflection, but also retains the insulation and thermal conductivity advantages of BNNS. Therefore, it has become a key factor in improving the electromagnetic wave absorption and thermal conductivity of MXene / boron nitride heterojunctions.
[0032] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, the simultaneous existence of A and B, or the existence of B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.
[0033] The above description is merely a specific embodiment of this application. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application. The protection scope of this application should be determined by the protection scope of the claims.
Claims
1. A method for constructing the electronic structure of a heterojunction based on first-principles calculations, characterized in that, include: Stable ground-state crystal structure files of Ti3AlC2 and h-BN were screened and obtained from the Materials Project crystal database to ensure that the lattice parameters and thermodynamic stability of the obtained crystal structures were experimentally verified. Constructing and optimizing Ti3C2T with different surface end groups X The MXene monolayer model was used to obtain its stable lattice constant, electronic structure, and density of states. Based on the optimized single-layer model, Ti3C2T with different end groups X A heterojunction model is constructed by combining single-layer and BNNS single-layer structures. The binding energy of the heterojunction is calculated using first-principles calculations. The geometric optimization and electronic structure calculations are then performed on the constructed heterojunction model to achieve multi-dimensional optimization of the heterojunction model.
2. The method for constructing the electronic structure of a heterojunction based on first-principles calculations according to claim 1, characterized in that, The construction and optimization of Ti3C2T with different surface end groups X The MXene monolayer model was used to obtain its stable lattice constant, electronic structure, and density of states, including: Ti3AlC2 was cut along a predetermined direction to obtain the initial Ti3C2 unit cell, and a 15Å vacuum layer was added. After convergence testing, the cutoff energy was determined. Functional groups (-O, -F, -OH) were added to its surface, and the structure was optimized to complete Ti3C2T. X The establishment of the MXene model.
3. The method for constructing the electronic structure of a heterojunction based on first-principles calculations according to claim 2, characterized in that, The structural optimization was carried out to complete the Ti3C2T. X The establishment of the MXene model includes: Simulations based on the CASTEP quantum mechanics program using first-principles calculations were conducted to study the exchange-correlation interaction in two-dimensional Ti3C2T using the PBE functional method with the generalized gradient approximation (GGA). X MXene performs geometry optimization; The interaction between electrons and atomic nuclei and ions is described using the OTFG ultrasoft pseudopotential. To describe weak interactions such as hydrogen bonds and van der Waals interactions, Grimme in DFT-D is used for dispersion correction. The metal option and the optimize cell option are selected to release stress, the precision is set to Ultra-fine, and the convergence criterion in structure optimization is set. The Brillouin zone integral grid was generated using the Monkhorst-Pack k-point sampling method to eliminate the potential interference of the crystal's periodicity along the Z-axis on the calculation results, and a vacuum layer was introduced in the Z-axis direction.
4. The method for constructing the electronic structure of a heterojunction based on first-principles calculations according to claim 1, characterized in that, Also includes: Before constructing the heterojunction model, construct the BNNS structure model.
5. The method for constructing the electronic structure of a heterojunction based on first-principles calculations according to claim 4, characterized in that, The construction of the BNNS structural model includes: The h-BN model imported from the Materials Project crystal database was sectioned along a set direction, and the thickness was adjusted to obtain a single-layer structure. Using the CASTEP module in MS software, add Grimme dispersion correction, uncheck "metal", check the "optimize cell" option, release stress, set the precision to "Ultra-fine", and optimize the BNNS single-layer structure by setting the convergence criteria in the structural optimization.
6. The method for constructing a heterojunction electronic structure based on first-principles calculations according to claim 4 or 5, characterized in that, Based on the optimized single-layer model, Ti3C2T with different end groups... X A heterojunction model is constructed by combining a single layer with a BNNS single layer, including: The geometric models of two crystal structures are stacked to form a rough heterojunction geometric model using the build layer function of MS software. Determining Ti3C2T based on lattice constant X MXene cell expansion and BNNS cell expansion; The expanded cell structures were optimized separately. During the heterojunction stacking process, the interlayer spacing of the MXene monolayer and the BNNS monolayer was set to the default value. The interlayer spacing was optimized to reach a thermodynamically stable value. During the optimization process, the atomic degrees of freedom within the layer were maintained, and the relative positions between the layers were constrained to avoid slippage.
7. The method for constructing the electronic structure of a heterojunction based on first-principles calculations according to claim 6, characterized in that, The method of stacking two crystal structure geometric models to construct a rough heterojunction geometric model by using the build layer function of MS software includes: using the build-build layers function of MS software, selecting the expanded cell MXene structure as the bottom layer in layer1 and the expanded cell BNNS structure as the top layer in layer2, selecting build layeredstructure as a crystal, and then building to establish a rough heterojunction model.
8. The method for constructing the electronic structure of a heterojunction based on first-principles calculations according to claim 1, characterized in that, Electronic structure calculations were performed on the constructed heterojunction model, including: based on the CASTEP module, selecting CASTEP Calculation and retaining the parameters of the geometry optimization; changing the Task to Energy, selecting Bandstructure and Density of states in the properties column, selecting GMKG for the Bandstructure path, and checking Calculate PDOS for the Density of states calculation.