Determination Method of Structural Phase Transition of Antimony Selenide Materials

Abstract

The present invention belongs to the technical field of photovoltaic material structural phase change, and provides a method for determining the structural phase change of Sb2Se3 materials. First, the material structure is optimized to obtain an optimized unit cell structure, and then the cell is expanded; based on the structure after cell expansion, different laser irradiation fluxes are set at 300K, and ab initio molecular dynamics simulation is performed in the system to obtain the system structure after irradiation with different laser fluxes; then, Rings software is used to obtain the pair correlation function and mean square displacement function of the system under different laser flux irradiation; finally, the obtained system structure, the pair correlation function and the mean square displacement function results are analyzed to determine the laser irradiation flux that causes the system structure phase change at 300K. The present invention adopts the ab initio molecular dynamics method, the system is complete, the simulation results are accurate, the repeatability is high, the whole process does not involve experiments and chemical supplies, the cost is low, and no chemical pollution is generated.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic material structural phase change, and in particular relates to a method for determining the structural phase change of antimony selenide (Sb2Se3) material. Background Art

[0002] As society develops, humanity's demand for energy continues to increase. According to surveys, fossil fuels such as crude oil and coal account for 87.7% of global energy consumption, while clean energy such as hydropower and nuclear power accounts for 12.3%. However, the massive consumption of fossil fuels has led to increasingly serious resource depletion and environmental pollution. Therefore, people are actively seeking a sustainable, green, and pollution-free new energy source. Among them, photovoltaic technology can directly convert solar radiation into electrical energy with an efficiency of between 5% and 20%, and is considered an effective solution. Sb2Se3 compounds are composed of elements that are abundant on Earth. They have advantages such as non-toxicity, high absorption coefficient, and optimal band gap, and have attracted increasing attention in the field of photovoltaic materials.

[0003] In the application fields of photovoltaic technology such as aerospace, communications, and transportation, photovoltaic materials are exposed to different radiation environments, such as proton, neutron, electron, and ion radiation, which may cause structural phase transitions in photovoltaic materials and have a significant impact on their photoelectric performance. 15 pcm -2 Under proton irradiation, a structural phase transition occurs, and the optical and electrical properties are significantly degraded. Therefore, it is crucial to study the microstructural evolution of photovoltaic materials under radiation environments.

[0004] In recent years, researchers have studied the effects of laser irradiation on the microstructural evolution of materials such as tungsten, silicon, and silver bromide, finding that exposure to a certain laser flux can induce structural phase transitions. Therefore, determining the structural phase transitions of the photovoltaic material Sb2Se3 under irradiation conditions using laser irradiation is feasible and can not only guide experiments to save time and costs, but also provide theoretical references for researchers. Summary of the Invention

[0005] In response to the problems existing in the prior art, the present invention provides a method for determining the structural phase transition of antimony selenide materials, comprising structural optimization of the material, obtaining the optimized unit cell structure and then expanding the cell; simulating irradiation with different laser fluxes using ab initio molecular dynamics to obtain the system structure after irradiation; and using Rings software to obtain the pair correlation function and mean square displacement function of the system under irradiation with different laser fluxes, and determining the laser irradiation flux that causes the system structure phase transition.

[0006] Furthermore, the method for determining the structural phase transition of the antimony selenide material comprises the following steps:

[0007] Step 1: Optimize the material structure, obtain the optimized unit cell structure and then expand the cell;

[0008] Step 2: Based on the supercell structure obtained in step 1, a 600 nm laser is selected, different laser irradiation fluxes are set at 300 K, and ab initio molecular dynamics simulations are performed in the system to obtain the system structure after irradiation with different laser fluxes;

[0009] Step 3: Based on the ab initio molecular dynamics simulation results obtained in step 2, software is used to obtain the correlation function and mean square displacement function of the system under different laser flux irradiation conditions;

[0010] Step 4: Based on the architecture obtained in steps 2 and 3, determine the laser irradiation flux that causes the phase change of the architecture at 300K for the correlation function and the mean square displacement function results.

[0011] Furthermore, in step 1, the material is structurally optimized to obtain an optimized unit cell structure and then the cell is expanded, which includes the following steps:

[0012] (1) Research the lattice constants and atomic coordinates of antimony selenide in the literature and construct a unit cell model of antimony selenide with 20 atoms in the cell;

[0013] (2) Setting the parameters ENCUT = 400 eV, ISIF = 3, and IBRION = 2, the CG algorithm was used to optimize the shape, volume, and atomic position of the antimony selenide unit cell;

[0014] (3) Based on the optimized unit cell structure obtained in step (2), the cell is expanded in a 2×2×6 manner, and the supercell contains 480 atoms.

[0015] Furthermore, in step 2, different laser irradiation fluxes are set at 300K, and ab initio molecular dynamics simulation is performed in the system to obtain the system structure after irradiation with different laser fluxes, including the following steps:

[0016] (1) Set the parameters IBRION = 0, TEBEG = TEEND = 300, and perform ab initio molecular dynamics simulation at a temperature of 300 K;

[0017] (2) Set the parameters POTIM = 1.5, NSW = 2000, and the simulation time to 3 ps;

[0018] (3) Set the K point to 1×1×1 and use the PBE functional under the generalized gradient approximation to describe the exchange-correlation interaction between electrons;

[0019] (4) Set NELECT=2688, 2621, 2554, 2420 respectively to simulate different laser irradiation fluxes 0mJ / cm 2 , 11.8mJ / cm 2 , 23.6mJ / cm 2 , 47.7mJ / cm 2 .

[0020] Furthermore, in step 3, the software is used to obtain the correlation function and mean square displacement function of the system under different laser flux irradiation, including the following steps:

[0021] (1) Prepare input files: input, options, data, rings;

[0022] (2) In the input file, enter the number of atoms, atomic type, lattice constant, ion step and step time;

[0023] (3) In the options file, set the periodic boundary condition PBC = .true., fractional coordinate Frac = .true., correlation function g(r) = .true., and mean square displacement function MSD = .true.

[0024] (4) In the data folder, prepare a file with the suffix .vas, which contains the architecture configuration of each ion step.

[0025] Furthermore, the software is Rings software.

[0026] Furthermore, in step 4, the laser irradiation flux that causes the structural phase change at 300K is determined, including analyzing the structural changes after irradiation, the long-range ordered changes of the correlation function, and the atomic diffusion reflected by the mean square displacement function.

[0027] In combination with the above technical solutions and the technical problems solved, the advantages of this technical solution and the positive effects it produces are:

[0028] (1) The present invention uses ab initio molecular dynamics to simulate laser irradiation in the photovoltaic material Sb2Se3. The entire process does not involve experiments or chemicals, is low in cost, and does not produce chemical pollution.

[0029] (2) The theoretical simulation method used in this invention is comprehensive and can accurately predict the structural phase transition of materials under irradiation. The simulation results fill the gap in the microstructural evolution of photovoltaic materials Sb2Se3 under irradiation, providing theoretical guidance for future practical applications.

[0030] (3) The technical solution of the present invention is simple to operate and highly repeatable. It solves the problem of predicting the structural phase transition of materials under irradiation environment and can be extended and applied to other systems with similar structures, such as Sb2S3 and Bi2S3. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a flow chart of a method for determining a structural phase transition of a Sb2Se3 material provided by an embodiment of the present invention;

[0032] Figure 2 Schematic diagram of the geometric structure of (a) a unit cell Sb2Se3 after structural optimization and (b) a super cell Sb2Se3 after cell expansion provided by an embodiment of the present invention;

[0033] Figure 3 The different laser fluxes (a) provided by the embodiments of the present invention are 0mJ / cm 2 ,(b)11.8mJ / cm 2 ,(c)23.6mJ / cm 2 ,(d)47.7mJ / cm 2 Schematic diagram of the geometric structure of the Sb2Se3 system under irradiation;

[0034] Figure 4 (a) correlation function diagram and (b) mean square displacement diagram of the Sb2Se3 system under different laser flux irradiation provided by the embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be noted that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] like Figure 1 As shown, the method for determining the structural phase transition of the Sb2Se3 material provided in the embodiment of the present invention includes the following steps:

[0037] S101, optimizing the material structure, obtaining the optimized unit cell structure and then expanding the cell;

[0038] S102, based on the supercell structure obtained in S101, different laser irradiation fluxes are set, and ab initio molecular dynamics simulation is performed in the system to obtain the system structure after irradiation;

[0039] S103, based on the simulation results obtained in S102, using software to obtain the correlation function and mean square displacement function of the system under different laser flux irradiation;

[0040] S104. Based on the results obtained in S102 and S103, determine the laser irradiation flux that causes the structural phase transition at 300K.

[0041] In step S101 provided in an embodiment of the present invention, the material is structurally optimized to obtain an optimized unit cell structure and then the cell is expanded, which includes the following steps:

[0042] Step 1.1: Research the lattice constants and atomic coordinates of antimony selenide in the literature and construct a unit cell model of antimony selenide with a total of 20 atoms. Sb2Se3 belongs to the orthorhombic crystal system with space group Pbnm(62). There are 20 atoms in the unit cell, of which the Sb atom has two inequivalent positions with coordination numbers of 5 and 3, and the Se atom has three inequivalent positions with coordination numbers of 3, 3, and 2, respectively.

[0043] Step 1.2, set the parameters ENCUT = 400eV, ISIF = 3, IBRION = 2, and use the CG algorithm to optimize the shape, volume, and atomic positions of the antimony selenide unit cell. The K point is 4×4×6, and the optimized graph is as follows Figure 2 As shown in (a), the optimized lattice constants are 11.59, 11.74, and 3.96 (as shown in Table 1), which are in good agreement with the experimental data (11.62, 11.77, and 3.96).

[0044] Table 1 Structural parameters of Sb2Se3

[0045]

[0046] Step 1.3: Based on the optimized unit cell structure obtained in step 1.2, the cell is expanded in a 2×2×6 manner. The supercell contains 480 atoms, as shown in Figure 2 (b) shown.

[0047] In step S102 provided in an embodiment of the present invention, based on the supercell structure obtained in S101, different laser irradiation fluxes are set, and ab initio molecular dynamics simulation is performed in the system to obtain the system structure after irradiation, including the following steps:

[0048] Step 2.1, set the parameters IBRION = 0, TEBEG = TEEND = 300, and perform ab initio molecular dynamics simulation at a temperature of 300 K;

[0049] Step 2.2, set the parameters POTIM = 1.5, NSW = 2000, and the simulation time to 3 ps;

[0050] Step 2.3, set the K point to 1×1×1, and use the PBE functional under the generalized gradient approximation to describe the exchange-correlation interaction between electrons;

[0051] Step 2.4, set NELECT = 2688, 2621, 2554, 2420, respectively, to simulate the laser irradiation flux of 0mJ / cm 2 , 11.8mJ / cm 2 , 23.6mJ / cm 2 , 47.7mJ / cm 2 .

[0052] In step S103 provided in an embodiment of the present invention, based on the simulation results obtained in S102, software is used to obtain the correlation function and mean square displacement function of the system under different laser flux irradiation, including the following steps:

[0053] Step 3.1, prepare input files input, options, data, rings;

[0054] Step 3.2: In the input file, enter the number of atoms, atomic type, lattice constant, ion step, and step time;

[0055] Step 3.3, in the options file, set the periodic boundary condition PBC = true, the fractional coordinate Frac = true, the pairwise correlation function g(r) = true, and the mean square displacement function MSD = true.

[0056] In step 3.4, prepare a file with the suffix .vas in the data folder, which contains the architecture configuration for each ion step.

[0057] In step S104 provided by the embodiment of the present invention, based on the results obtained in S102 and S103, the laser irradiation flux that causes the phase change of the structural system at 300K is determined, including analyzing the changes in the structural system after irradiation, the long-range order changes of the correlation function, and the atomic diffusion reflected by the mean square displacement function. Figure 3 As shown, when there is no laser irradiation, the crystal structure is ordered; at 11.8 mJ / cm 2 Under laser irradiation, the crystal structure changes very little; when the irradiation flux increases to 23.6mJ / cm 2 , the crystal structure begins to show local disorder, while the majority of the structure remains ordered; at 47.7 mJ / cm 2 Under laser irradiation, the crystal structure of Sb2Se3 undergoes phase transition. The pair correlation function of the system, such as Figure 4 As shown in (a), at 47.7 mJ / cm 2 Under laser irradiation, the Sb2Se3 structure maintains order in the short range and loses order in the long range, indicating that the 47.7mJ / cm 2 Laser irradiation can induce structural phase transition of Sb2Se3 at 300K. Figure 4 (b) shows the mean square displacement function of Se atoms and Sb atoms in Sb2Se3 under different laser flux irradiation. When the irradiation flux increases to 47.7mJ / cm 2 Quantitatively, the mean square displacement of Sb atoms is lower than that of Se atoms, which means that the structural phase transition of Sb2Se3 is mainly caused by the displacement of Se atoms.

[0058] The technical solution provided by the embodiment of the present invention has been applied in different material systems. In addition to the photovoltaic material Sb2Se3 mentioned above, the applied system materials include La2Zr2O7, W, and Sb2Te3. Taking the Sb2Te3 system as an example, according to Figure 1 The flow chart of the method for determining the structural phase transition of Sb2Se3 material is shown. First, the 2×3×1 supercell with optimized structure is obtained. Then, the ab initio molecular dynamics method is used to simulate different laser flux irradiation to obtain the structure after irradiation. The correlation function and mean square displacement function are used to determine that the laser irradiation flux that causes the structural phase transition is 20.3mJ / cm 2 .

[0059] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for determining the structural phase transition of antimony selenide material, characterized in that: This involves optimizing the material structure, obtaining the optimized unit cell structure, and then expanding the cell; using ab initio molecular dynamics to simulate different laser flux irradiation to obtain the system structure after irradiation; using Rings software to obtain the pair correlation function and mean square displacement function of the system under different laser flux irradiation, and determining the laser irradiation flux that causes the phase change of the system structure; The method for determining the structural phase transition of the antimony selenide material comprises the following steps: Step 1: Optimize the material structure, obtain the optimized unit cell structure and then expand the cell; Step 2: Based on the supercell structure obtained in step 1, a 600 nm laser is selected, different laser irradiation fluxes are set at 300 K, and ab initio molecular dynamics simulations are performed in the system to obtain the system structure after irradiation with different laser fluxes; Step 3: Based on the ab initio molecular dynamics simulation results obtained in step 2, software is used to obtain the correlation function and mean square displacement function of the system under different laser flux irradiation conditions; Step 4: Based on the architecture obtained in steps 2 and 3, determine the laser irradiation flux that causes the phase change of the architecture at 300K for the correlation function and the mean square displacement function results.

2. The method for determining the structural phase transition of antimony selenide material according to claim 1, wherein: In the step 1, the material is structurally optimized to obtain an optimized unit cell structure and then the cell is expanded, including the following steps: (1) Check the lattice constant and atomic coordinates of antimony selenide and construct a unit cell model of antimony selenide, which contains 20 atoms. (2) Set the parameters ENCUT = 400 eV, ISIF = 3, IBRION = 2, and use the CG algorithm to optimize the shape, volume, and atomic position of the antimony selenide unit cell; (3) Based on the optimized unit cell structure obtained in step (2), the cell is expanded in a 2×2×6 manner, and the supercell contains 480 atoms.

3. The method for determining the structural phase transition of antimony selenide material according to claim 1, wherein: In the second step, different laser irradiation fluxes are set at 300K, and ab initio molecular dynamics simulation is performed in the system to obtain the system structure after irradiation with different laser fluxes, which includes the following steps: (1) Set the parameters IBRION=0, TEBEG=TEEND=300 and perform ab initio molecular dynamics simulation at a temperature of 300 K; (2) Set the parameters POTIM=1.5, NSW=2000, and simulation time to 3 ps; (3) Set the K point to 1×1×1 and use the PBE functional under the generalized gradient approximation to describe the exchange correlation between electrons; (4) Set NELECT=2688, 2621, 2554, 2420 respectively to simulate different laser irradiation fluxes 0 mJ / cm 2 , 11.8mJ / cm 2 , 23.6 mJ / cm 2 , 47.7 mJ / cm 2 .

4. The method for determining the structural phase transition of antimony selenide material according to claim 1, wherein: In the step 3, software is used to obtain the correlation function and mean square displacement function of the system under different laser flux irradiation, which includes the following steps: (1) Prepare input files: input, options, data, rings; (2) In the input file, enter the number of atoms, atomic type, lattice constant, ion step and step time; (3) In the options file, set the periodic boundary condition PBC = .true., fractional coordinate Frac = .true., correlation function g(r) = .true., and mean square displacement function MSD = .true. (4) In the data folder, prepare a file with the suffix .vas, which contains the architecture configuration of each ion step.

5. The method for determining the structural phase transition of antimony selenide material according to claim 1 or 4, characterized in that: The software is Rings software.

6. The method for determining the structural phase transition of antimony selenide material according to claim 1, wherein: In the step 4, the laser irradiation flux that causes the structural phase change at 300K is determined, including analyzing the structural changes after irradiation, the long-range ordered changes of the correlation function, and the atomic diffusion reflected by the mean square displacement function.

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