A novel perovskite composite material and its method for bandgap regulation

Abstract

The present invention relates to a novel perovskite composite material, comprising an ABX3-type all-inorganic perovskite and two-dimensional MXene; the molar ratio of the two is (1~50):1; in the ABX3-type all-inorganic perovskite, the A site is replaced by Cs, the B site is replaced by Pt, and the X site is replaced by a halogen element; the two-dimensional MXene is a transition metal carbide, nitride or boride, which is non-toxic and harmless compared with traditional all-inorganic perovskites and has a band gap adapted to the application of optoelectronic materials; the present invention also relates to a method for regulating the band gap of the material. By selecting the initial material, constructing a theoretical model and a composite material, optimizing the structure to calculate the composite energy, selecting a theoretically stable model, and analyzing the results after band gap calculation, the size of the band gap can be regulated efficiently and quickly by changing the doping ratio of two-dimensional MXene, and the structure and composition of the CsPtX3 / MXene composite material with a stable structure and a band gap of about 1.5 eV can be obtained, thereby reducing the complexity of the operation of experimentally finding a suitable band gap material, shortening the R & D cycle of new materials and saving costs, and having important practical application value.

Description

Technical Field

[0001] The present invention relates to the technical field of the design and development of optoelectronic materials, and particularly to a novel perovskite composite material and a method for regulating its band gap. Background Art

[0002] All-inorganic perovskite materials (CsPbX 3 , X = Cl, Br, I) have become outstanding in optoelectronic materials due to their excellent optoelectronic properties, such as high quantum efficiency and narrow full width at half maximum, and are used in fields such as backlight displays, solar cells, and LED lighting; however, their stability problems seriously limit their development in commercial applications. At the same time, since CsPbX 3 contains lead, it is harmful to the human body and causes certain pollution to the environment.

[0003] In the research of perovskite ABX 3 , methods such as doping and surface engineering are important means to improve the thermal stability, spectral stability, and photo stability of perovskite ABX 3 ; MXene materials are a new type of two-dimensional transition metal carbide or carbonitride, which are obtained by selectively etching the A layer in MAX phase materials. The chemical general formula of MXene is M n+1 X n T x . Among them, M represents transition metals (Ti, V, Cr, Mo, etc.), X represents carbon or nitrogen, n = 1 - 3, and T x represents surface functional groups, such as F, O, and OH. MXene materials have excellent thermal stability, electrical conductivity, hydrophilicity, and mechanical properties, as well as a high specific surface area and interlayer ion storage capacity, making them very promising 2D materials that can be applied to fields such as solar cells and photocatalysis.

[0004] Developing a new type of stable, harmless material that can be applied to the optoelectronic field has very important practical value. Summary of the Invention

[0005] The purpose of the present invention is to provide a novel perovskite composite material and a method for regulating its band gap. The novel perovskite composite material is non-toxic and harmless compared to traditional all-inorganic perovskites, and its band gap is adapted to the application of optoelectronic materials; the method for regulating the band gap of the novel perovskite composite material can efficiently and quickly regulate the size of the band gap by changing the doping ratio of two-dimensional MXene materials, and obtain a stable structure of the perovskite composite material composition.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A novel perovskite composite material, comprising:

[0008] ABX 3 type all-inorganic perovskite and two-dimensional MXene;

[0009] The ABX 3 type all-inorganic perovskite and two-dimensional MXene have a molar ratio of (1 to 50):1;

[0010] The ABX 3 In the type all-inorganic perovskite, the element replacing the A site is Cs, the transition element replacing the B site is Pt, and the element replacing the X site is a halogen element;

[0011] The two-dimensional MXene is a transition metal carbide, nitride or boride.

[0012] Preferably, the halogen element includes Cl, Br, I, and the element replacing the X site is one or more arbitrary combinations of Cl, Br, I.

[0013] Preferably, the carbide is M 2 C, M 3 C 2 、M 4 C 3 One of them; the nitride includes M 2 N, M 3 N 2 And M 4 N 3 One of them; the boride includes M 2 B 2 、M 3 B 4 And M 4 B 6 One of them.

[0014] A method for regulating the band gap of a novel perovskite composite material, comprising the following steps:

[0015] S1: Using the Materials Studio software package, perform band gap calculations on uncomposed CsPtX 3 in the order of (GGA-PBE)-HSE03-HSE06, and select two-dimensional MXene with conductivity to construct a composite material with CsPtX 3 ;

[0016] S2: According to the molar ratio of CsPtX 3 perovskite and two-dimensional MXene, use Materials Studio to construct a model and construct a CsPtX 3 / MXene theoretical model;

[0017] S3: According to the theoretical model of S2, construct CsPtX3 / MXene composite material;

[0018] S4: Establish a theoretical model according to S2, optimize the heterostructure with Materials Studio, and calculate CsPtX 3 binding energy of the / MXene composite material;

[0019] S5: Select a stable CsPtX 3 / MXene heterostructure model and the corresponding CsPtX 3 / MXene composite material;

[0020] S6: Based on the CsPtX 3 / MXene composite material in S5, perform band gap calculations with Materials Studio, and successively perform step-by-step band gap calculations in the order of (GGA-PBE)-HSE03-HSE06 to obtain the band gap calculation results;

[0021] S7: Analyze the band gap calculation results to obtain the material structure and composition of the CsPtX 3 / MXene composite material with a band gap of 1.5 eV.

[0022] Preferably, in S3, when the molar ratio of CsPtX 3 perovskite and two-dimensional MXene is (50~21):1, the two-dimensional MXene serves as the composite material core, and the CsPtX 3 perovskite is coated on the surface of the two-dimensional MXene to construct a composite material;

[0023] CsPtX 3 When the molar ratio of perovskite and two-dimensional MXene is (20~1):1, a composite material is constructed in the form of a stacked sandwich structure, and a model is established according to the CsPtX 3 perovskite-two-dimensional MXene-CsPtX 3 three-layer sandwich structure of perovskite.

[0024] Preferably, the binding energy of the CsPtX 3 / MXene composite material in S4 is E binding = E CsPtX3 / MXene - E CsPtX3 - E MXene ; where E CsPtX3 / MXene is the total energy of the composite material, E CsPtX3 is CsPtX 3Total energy of perovskite E MXene is the total energy of two-dimensional MXene

[0025] Preferably, the constraint condition is CsPtX 3 The binding energy of the / MXene composite material is less than 0

[0026] Preferably, in the S2, corresponding CsPtX is constructed according to different molar ratio gradients 3 The perovskite and two-dimensional MXene theoretical models, and each of the theoretical models is repeated in S3~S7

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows

[0028] In the above technical solution, the novel perovskite composite material provided is non-toxic and harmless compared with the traditional all-inorganic perovskite, and the band gap is adapted to the application of optoelectronic materials; the band gap regulation method of the novel perovskite composite material can efficiently and quickly regulate the size of the band gap by changing the doping ratio of the two-dimensional MXene material, and obtain a CsPtX with a stable structure and a band gap of about 1.5 eV 3 The structure and composition of the / MXene composite material, thereby reducing the complexity of the operation of experimentally finding a suitable band gap material, shortening the R & D cycle of new materials and saving costs, and having important practical application value BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of the theoretical model of the perovskite material CsPtCl provided by the embodiment of the present invention 3

[0030] Figure 2 is a schematic diagram of the theoretical model of the two-dimensional MXene Ti provided by the embodiment of the present invention 3 C 2

[0031] Figure 3 is a schematic diagram of the band gap of the perovskite material CsPtCl provided by the embodiment of the present invention 3

[0032] Figure 4 is a schematic diagram of the band gap of the CsPtCl provided by the embodiment of the present invention 3 / Ti 3 C 2 DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] ​​​​The invention will be described in more detail below with reference to the accompanying drawings. It should be noted that the description of the present invention with reference to the accompanying drawings is illustrative only and not restrictive. Combinations can be made between different embodiments to form other embodiments not shown in the following description.

[0034] The novel perovskite composite material of the present invention comprises an ABX 3 type all-inorganic perovskite and two-dimensional MXene; wherein, in the ABX 3 type all-inorganic perovskite, the element replacing the A site is Cs, the transition element replacing the B site is Pt, and the element replacing the X site is a halogen element, and the halogen elements include Cl, Br, I, and the element replacing the X site is one or more arbitrary combinations of Cl, Br, I; for example, CsPtCl 3 , CsPtBr 3 , CsPtI 3 , CsPtCl 2 Br, CsPtCl 2 I, CsPtClBrI, CsPtClBr 2 , CsPtClI 2 and so on;

[0035] Two-dimensional MXene is a transition metal carbide, nitride or boride, including M 2 C, M 3 C 2 , M 4 C 3 , M 2 N, M 3 N 2 , M 4 N 3 , M 2 B 2 , M 3 B 4 and M 4 B 6 and so on. Specifically, there are Ti 2 C, Ti 2 N, V 2 C, Nb 2 C, Ti 3 C 2 , Ti 3 CN, Nb 4 C 3 , Ta 4 C 3 , Ti 4 N 3 , Mo 2 Ti 2 C 3Potential structures such as these and two-dimensional materials that may have various single (-O, -Cl, -F, etc.) or mixed (O / OH / F) surface terminal groups;

[0036] The novel perovskite composite material is non-toxic and harmless compared to traditional all-inorganic perovskites, and its bandgap is suitable for the application of optoelectronic materials.

[0037] The method for regulating the bandgap of the novel perovskite composite material of the present invention includes the following steps:

[0038] (1) Selection of initial materials;

[0039] Using the Materials Studio software package, the bandgap of uncomposited CsPtX is calculated according to the progressive order of (GGA-PBE)-HSE03-HSE06, and CsPtX with a bandgap greater than 1.5 eV or a bandgap less than 1.5 eV is selected. 3 Perovskite; Select two-dimensional MXene with conductivity, preferably two-dimensional MXene with good conductivity. 3

[0040] (2) Construction of a theoretical model

[0041] Mix CsPtX 3 Perovskite and two-dimensional MXene in a molar ratio, and use Materials Studio to construct a model to construct a CsPtX 3 / MXene theoretical model, and the molar ratio of CsPtX 3 Perovskite and two-dimensional MXene is (1~50):1.

[0042] (3) Construction of a composite material

[0043] According to the theoretical model in step (2), construct a CsPtX 3 / MXene composite material;

[0044] CsPtX 3 When the molar ratio of perovskite and two-dimensional MXene is (50~21):1, two-dimensional MXene serves as the core of the composite material, and CsPtX 3 Perovskite is coated on the surface of two-dimensional MXene to construct a composite material;

[0045] CsPtX 3 When the molar ratio of perovskite and two-dimensional MXene is (20~1):1, construct a composite material in the form of a stacked sandwich structure, and establish a model according to the three-layer sandwich structure of CsPtX 3 Perovskite-two-dimensional MXene-CsPtX 3 Perovskite.

[0046] ​(4) Optimize the structure and calculate the composite energy

[0047] According to the theoretical model, optimize the heterostructure with Materials Studio and calculate the binding energy of CsPtX 3 / MXene composite; the binding energy of CsPtX 3 / MXene composite is E binding = E CsPtX3 / MXene - E CsPtX3 - E MXene ; where E CsPtX3 / MXene is the total energy of the composite material, E CsPtX3 is the total energy of CsPtX 3 perovskite, E MXene is the total energy of two-dimensional MXene.

[0048] (5) Select a theoretically stable model

[0049] According to the constraint condition: when the binding energy of CsPtX 3 / MXene composite is less than 0, select a structurally stable heterogenous model, and determine the construction of CsPtX 3 / MXene composite according to the above model.

[0050] (6) Band gap calculation

[0051] Perform band gap calculations with Materials Studio, and successively perform stepwise band gap calculations in the order of (GGA-PBE)-HSE03-HSE06. During the calculation process, it is an appropriate method to use low precision for preliminary optimization and further improve the precision on the basis of obtaining a stable structural model, which can significantly improve the calculation efficiency and reduce the calculation workload, and helps to quickly obtain the band gap calculation results.

[0052] (7) Analyze the band gap calculation results

[0053] According to the band gap calculation results obtained in step (6), select a CsPtX 3 / MXene composite with a band gap of about 1.5 eV, and obtain the structure and composition of the CsPtX 3 / MXene composite.

[0054] The following takes the CsPtX 3 / MXene composite as an example to illustrate the method of the present invention in detail.

[0055] The halogen element selected to replace the X position in this embodiment is Cl, that is, CsPtCl 3 perovskite; in the selection of two-dimensional MXene, the conductivity of carbides is better than that of nitrides and borides, and two-dimensional MXene selects Ti 3 C 2 ;

[0056] Using the Materials Studio software package, the band gap of uncomposited CsPtCl was calculated in the order of (GGA-PBE)-HSE03-HSE06 3 to obtain a band gap of 2.2 eV for CsPtCl 3 . Taking this as the research object, Ti with excellent conductivity was selected 3 C 2 ; Ti 3 C 2 was doped into CsPtCl 3 to obtain CsPtCl 3 / Ti 3 C 2 composite material to achieve the purpose of reducing the band gap of CsPtCl 3 perovskite.

[0057] CsPtCl 3 perovskite and Ti 3 C 2 were doped in a molar ratio of 1:1, and the model was constructed through Materials Studio to construct the CsPtCl 3 / MXene theoretical model. When the molar ratio exceeds 1:1, the band gap of CsPtCl 3 perovskite has a tendency to transform into a conductor; within the modification range of 1:50-1:1, if the band gap is higher than 1.5 eV, the doping amount is further increased, and if the band gap is lower than 1.5 eV, the doping amount needs to be reduced; therefore, the CsPtCl 3 perovskite and Ti 3 C 2 were adjusted according to the molar ratio. CsPtCl 3 perovskite and Ti 3 C 2 were respectively constructed into CsPtCl 3 / MXene theoretical models according to molar ratios of 20:1, 30:1, and 50:1;

[0058] CsPtCl 3 perovskite and Ti 3 C 2 When the molar ratio is 1:1, according to CsPtCl 3 perovskite-Ti 3 C2 -CsPtCl 3 The three-layer sandwich structure of perovskite was modeled to obtain Composite Material 1, and the total energy of Composite Material 1 was -2.15×10 4 eV;

[0059] CsPtCl 3 Perovskite and Ti 3 C 2 When the molar ratio was 20:1, according to CsPtCl 3 Perovskite-Ti 3 C 2 -CsPtCl 3 The three-layer sandwich structure of perovskite was modeled to obtain Composite Material 2, and the total energy of Composite Material 2 was -7.08×10 4 eV;

[0060] CsPtCl 3 Perovskite and Ti 3 C 2 When the molar ratio was 30:1, Ti 3 C 2 was used as the core, and CsPtCl 3 perovskite was coated on the surface of Ti 3 C 2 to construct the CsPtCl 3 / Ti 3 C 2 composite material to obtain Composite Material 3, and the total energy of Composite Material 3 was -9.08×10 4 eV;

[0061] CsPtCl 3 Perovskite and Ti 3 C 2 When the molar ratio was 50:1, Ti 3 C 2 was used as the core, and CsPtCl 3 perovskite was coated on the surface of Ti 3 C 2 to construct the CsPtCl 3 / Ti 3 C 2 composite material to obtain Composite Material 4, and the total energy of Composite Material 4 was -1.29×10 5 eV;

[0062] According to the formula E binding = E CsPtX3 / MXene - E CsPtX3 -E MXene Calculate the binding energies of the above composite materials respectively. Among them, CsPtCl 3 The total energy of perovskite is -5.68×10 3 eV, and the total energy of Ti 3 C 2 is -1.02×10 4 eV. The binding energy of composite material one is obtained as 59.68 eV, the binding energy of composite material two is -96.27 eV, the binding energy of composite material three is -107.76 eV, and the binding energy of composite material four is 231.91 eV;

[0063] According to the above calculation results and constraints, when the binding energy is less than 0, select the models with stable structures; that is, composite material two and composite material three;

[0064] For composite material two, perform band gap calculations with Materials Studio, and conduct step-by-step band gap calculations in the order of (GGA-PBE)-HSE03-HSE06, and obtain the band gap calculation results, with the band gap being 1.72 eV;

[0065] For composite material three, perform band gap calculations with Materials Studio, and conduct step-by-step band gap calculations in the order of (GGA-PBE)-HSE03-HSE06, and obtain the band gap calculation results, with the band gap being 1.61 eV;

[0066] According to the above calculation results, dope Ti 3 C 2 with CsPtCl 3 in a molar ratio of 1:(20~30). It can be known that the band gap of the CsPtCl 3 / Ti 3 C 2 composite material is closest to 1.5 eV.

[0067] Mix Ti 3 C 2 , CsCl, and chloroplatinic acid in a molar ratio, and prepare them in a hydrothermal reaction kettle. Test the band gap of the obtained CsPtCl 3 / Ti 3 C 2 band gap, compare the band gap of the obtained material in the control experiment with the calculation results, optimize the experimental process, and obtain the band gap value closest to the theoretical calculation results.

[0068] Based on the above CsPtCl 3 / Ti 3 C 2 example, refer to the relevant steps to conduct CsPtX with different halogen ions3 Perovskites, including CsPtCl 3 , CsPtBr 3 , CsPtI 3 , CsPtCl 2 Br, CsPtCl 2 I, CsPtClBrI, CsPtClBr 2 , CsPtClI 2 and a variety of two-dimensional MXenes, including Ti 2 C, Ti 2 N, V 2 C, Nb 2 C, Ti 3 C 2 , Ti 3 CN, Nb 4 C 3 , Ta 4 C 3 , Ti 4 N 3 , Mo 2 Ti 2 C 3 The related research on the constructed CsPtX 3 / MXene composite materials to explore the doping ratio closest to the band gap of 1.5 eV will not be elaborated here.

[0069] The method of the present invention constructs a CsPtX 3 / MXene composite material model through Materials Studio software, calculates the band gap in the order of (GGA-PBE)-HSE03-HSE06, obtains a suitable doping ratio accordingly, and obtains the structure and composition of the CsPtX 3 / MXene composite material with stable structure and a band gap of about 1.5 eV, thereby reducing the complexity of the operation of experimentally finding materials with suitable band gaps, shortening the R & D cycle of new materials and saving costs, and having important practical application value.

[0070] The above embodiments are only the preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art on the basis of the present invention belong to the scope of protection required by the present invention.

Claims

1. A method for regulating the band gap of a perovskite composite material, characterized in that: The following steps are involved: S1: Using the Materials Studio software package, the band gap of uncompounded CsPtX3 was calculated in the progressive order of (GGA-PBE)-HSE03-HSE06, and conductive two-dimensional MXene and CsPtX3 were selected to construct composite materials; S2: CsPtX3 perovskite and two-dimensional MXene are mixed in molar ratios and the model is constructed using Materials Studio to construct a CsPtX3 / MXene theoretical model. S3: According to the theoretical model of S2, CsPtX3 / MXene composite material is constructed; S4: Establish a theoretical model based on S2, optimize the heterostructure with Materials Studio, and calculate the binding energy of CsPtX3 / MXene composite materials; S5: Select stable CsPtX3 / MXene heterogeneous models and corresponding CsPtX3 / MXene composites according to the constraints; S6: According to the CsPtX3 / MXene composite material in S5, the band gap calculation is performed using Materials Studio, and the step-by-step band gap calculation of (GGA-PBE)-HSE03-HSE06 is performed in sequence to obtain the band gap calculation results; S7: Analyze the band gap calculation results to obtain the material structure and composition of CsPtX3 / MXene composite materials with a band gap of 1.5 eV; Perovskite composite materials, including: ABX3-type all-inorganic perovskites and two-dimensional MXenes; The molar ratio of the ABX3-type all-inorganic perovskite to the two-dimensional MXene is (1-50):1; In the ABX3-type all-inorganic perovskite, the element replacing the A position is Cs, the transition element replacing the B position is Pt, the element replacing the X position is a halogen element, the halogen element includes Cl, Br, I, and the element replacing the X position is any combination of one or more of Cl, Br, and I; The two-dimensional MXene is a transition metal carbide, nitride or boride.

2. The band gap control method of the perovskite composite material according to claim 1, characterized in that: The carbide is one of M2C, M3C2, and M4C3; the nitride includes one of M2N, M3N2, and M4N3; and the boride includes one of M2B2, M3B4, and M4B6.

3. The band gap control method of the perovskite composite material according to claim 1, characterized in that: In S3, when the molar ratio of CsPtX3 perovskite to two-dimensional MXene is (50-21):1, the two-dimensional MXene is used as the core of the composite material, and the CsPtX3 perovskite is coated on the surface of the two-dimensional MXene to construct the composite material; When the molar ratio of CsPtX3 perovskite and two-dimensional MXene is (20~1):1, a composite material is constructed in the form of a stacked sandwich structure, and a model is established according to the three-layer sandwich structure of CsPtX3 perovskite-two-dimensional MXene-CsPtX3 perovskite.

4. The band gap control method of the perovskite composite material according to claim 1, characterized in that: The binding energy of the CsPtX3 / MXene composite material in S4 is E binding = E CsPtX3 / MXene - E CsPtX3 - E MXene ; in, E CsPtX3 / MXene is the total energy of the composite material, E CsPtX3 is the total energy of CsPtX3 perovskite, E MXene is the total energy of the two-dimensional MXene.

5. The band gap control method of the perovskite composite material according to claim 1, characterized in that: The constraint condition is that the binding energy of the CsPtX3 / MXene composite material is less than 0.

6. The band gap control method of the perovskite composite material according to claim 3, characterized in that: In S2, corresponding CsPtX3 perovskite and two-dimensional MXene theoretical models are constructed according to different molar ratio gradients, and each of the theoretical models is repeated in S3 to S7.

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