Perovskite film and preparation method thereof, solar cell and photovoltaic module

Abstract

The invention relates to the technical field of perovskite films, in particular to a perovskite film and a preparation method thereof, a solar cell and a photovoltaic module. The perovskite film comprises a perovskite material with a chemical general formula of ABX3 and a passivation material with a chemical general formula of R-(CH2) n-CH (NH2)-COOM, wherein in the general chemical formula of the perovskite material, B represents a divalent metal ion, A represents an organic amine cation or a cesium ion, and X represents a halide ion; in the chemical general formula of the passivation material, the R group represents a Lewis base group, the M represents alkali metal ions, the alkali metal ions and halide ions can form ionic bonds, and n is a positive integer smaller than 5. The passivation material not only can improve the crystallization quality of the perovskite film, but also can inhibit ion migration, so that the electrical property and the stability of the perovskite film are improved, and the conversion efficiency of the solar cell with the perovskite film is further improved.

Description

Technical Field

[0001] This application relates to the field of perovskite film technology, and in particular to a perovskite film and its preparation method, solar cells, and photovoltaic modules. Background Technology

[0002] The main factors affecting the performance of perovskite films include the crystallinity of the perovskite film and ion migration within it. Poor crystallinity leads to lower electrical performance, while ion migration can disrupt the basic framework of the perovskite film, causing defects such as lattice changes and uneven phase distribution. These defects are detrimental to the conversion efficiency and stability of solar cells. Summary of the Invention

[0003] This application discloses a perovskite film and its preparation method, a solar cell, and a photovoltaic module. It can improve the crystal quality of the perovskite film and suppress ion migration, thereby improving the electrical performance and stability of the perovskite film. The conversion efficiency of the solar cell with the perovskite film is further improved.

[0004] To achieve the above objectives, in a first aspect, embodiments of this application disclose a perovskite film comprising a perovskite material with the chemical formula ABX3 and a perovskite material with the chemical formula R-(CH2). n Passivation materials for -CH(NH2)-COOM;

[0005] In the general chemical formula of the perovskite material, B represents a divalent metal ion, A represents an organic amine cation or a cesium ion, and X represents a halide ion;

[0006] In the chemical formula of the passivation material, R group represents Lewis base group, M represents alkali metal ion, the alkali metal ion can form ionic bond with the halide ion, and n is a positive integer less than 5.

[0007] In one possible implementation of the first aspect, in the chemical formula of the passivating material, R group represents any one of carboxyl group, sulfonic acid group or phosphate group, M represents sodium ion or potassium ion, and n is 2.

[0008] In one possible implementation of the first aspect, the passivating material is sodium glutamate or potassium glutamate.

[0009] In one possible implementation of the first aspect, the passivating material is doped into the bulk phase of the perovskite film.

[0010] In one possible implementation of the first aspect, the passivating material is distributed on the surface of the perovskite film.

[0011] In a possible implementation of the first aspect, the divalent metal ion is selected from at least one of lead ions or tin ions;

[0012] And / or, the halide ion is selected from at least one of chloride ions, bromide ions, or iodide ions;

[0013] And / or, the organic amine cation is selected from at least one of formamidinium ion or methylamine ion;

[0014] And / or, the thickness of the perovskite film is 400 nm to 1000 nm.

[0015] Secondly, embodiments of this application disclose a method for preparing a perovskite film as described in the first aspect, comprising the following steps:

[0016] A framework layer is prepared on a substrate; wherein the framework layer contains a first precursor material with the general chemical formula BX2, wherein in the general chemical formula of the first precursor material, B represents a divalent metal ion and X represents a halide ion.

[0017] An organic salt solution is coated on the skeleton layer; wherein the organic salt solution comprises a first solvent, the passivation material, and an organic salt with the general chemical formula AX, wherein A represents an organic amine cation and X represents a halide ion.

[0018] The substrate coated with the organic salt solution is annealed to obtain the perovskite film.

[0019] In a possible implementation of the second aspect, the molar concentration of the organic amine cation in the organic salt solution is 0.5 mol / L to 1.5 mol / L, and the molar concentration of the passivating material is 0.002 mol / L to 0.015 mol / L.

[0020] And / or, the first solvent is anhydrous ethanol;

[0021] And / or, the organic salt is selected from at least one of formamidin hydroiodate, methylamine bromide, or methylamine chloride;

[0022] And / or, the first precursor material is PbI2.

[0023] Thirdly, embodiments of this application disclose a method for preparing a perovskite film as described in the first aspect, comprising the following steps:

[0024] A wet film is prepared by coating a perovskite precursor solution onto a substrate; wherein the perovskite precursor solution comprises a second solvent, the passivation material, and a second precursor material;

[0025] The solvent on the surface of the wet film is removed, and the perovskite film is obtained by annealing and crystallization treatment.

[0026] In a possible implementation of the third aspect, the molar concentration of the passivating material in the perovskite precursor solution is 0.002 mol / L to 0.015 mol / L, and the molar concentration of the second precursor material is 1 mol / L to 1.2 mol / L.

[0027] And / or, the second precursor material is FAPbI3;

[0028] And / or, the second solvent is dimethylformamide.

[0029] Fourthly, embodiments of this application disclose a method for preparing a perovskite film as described in the first aspect, comprising the following steps:

[0030] Prepare the perovskite film containing the perovskite material;

[0031] A passivation material solution is coated on the surface of the perovskite film; wherein the passivation material solution contains the passivation material and a third solvent.

[0032] In a possible implementation of the fourth aspect, the concentration of the passivating material in the passivating material solution is 0.8 mg / mL to 1.2 mg / mL, and the coating amount of the passivating material solution is 20 μL / cm. 2 ~40μL / cm 2 ;

[0033] And / or, the third solvent is isopropanol.

[0034] Fifthly, embodiments of this application disclose a solar cell, including a first carrier transport layer, a second carrier transport layer, and a perovskite film as described in the first aspect, or a perovskite film prepared according to the preparation method described in the second, third, or fourth aspects.

[0035] The first carrier transport layer and the second carrier transport layer are respectively disposed on two opposite surfaces of the perovskite film; one of the two carrier transport layers is an electron transport layer and the other is a hole transport layer.

[0036] In a possible implementation of the fifth aspect, the solar cell further includes a bottom cell, an intermediate composite layer, a composite electron transport layer, a barrier layer, and electrodes;

[0037] The bottom cell has a top surface, and the intermediate composite layer, the hole transport layer, the perovskite film, the electron transport layer, the composite electron transport layer, the blocking layer, and the electrode are sequentially stacked on the top surface in a direction away from the bottom cell.

[0038] Sixthly, embodiments of this application disclose a photovoltaic module, including a plurality of solar cells connected in series and / or in parallel, wherein at least one of the solar cells is the solar cell described in the fifth aspect.

[0039] Compared with the prior art, the beneficial effects of this application are: the perovskite film contains perovskite material and has the general chemical formula R-(CH2). n The passivating material, -CH(NH2)-COOM, contains carbonyl, amino, and R groups in its molecule. All three groups are Lewis bases capable of donating lone pairs of electrons. In the general chemical formula for perovskite materials, the B group represents a divalent metal ion with two empty orbitals, belonging to a Lewis acid capable of accepting lone pairs of electrons. All three Lewis base groups can form Lewis acid-base adducts with the divalent metal ion, slowing down the nucleation and crystallization process and improving crystal quality. Furthermore, the alkali metal ions in the passivating material molecule can form ionic bonds with halide ions in the perovskite material, increasing the activation energy of halide ion migration, inhibiting ion migration, reducing halide vacancy formation, and improving the stability of the perovskite film.

[0040] In summary, this passivation material can improve the crystallinity of the perovskite film, thereby optimizing the crystallization orientation of the perovskite crystals, improving crystallinity, and controlling the band gap. Furthermore, this passivation material can suppress ion migration, enhance the stability of the perovskite material, and thus improve the electrical performance and stability of the perovskite film, further increasing the conversion efficiency of solar cells using this perovskite film. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the structure of a solar cell disclosed in an embodiment of this application;

[0043] Figure 2 The image shows a SEM image of the perovskite film surface in Comparative Example 1.

[0044] Figure 3 This is a SEM image of the perovskite film surface in Example 1.

[0045] Explanation of reference numerals in the attached figures: 100, solar cell; 101, bottom cell; 102, intermediate composite layer; 103, hole transport layer; 104, perovskite film; 105, electron transport layer; 106, composite electron transport layer; 107, barrier layer; 108, electrode. Detailed Implementation

[0046] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0047] In this application, the terms "upper," "top," "bottom," "inner," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0048] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0049] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance or quantity of the devices, components, or parts indicated.

[0050] To address the ion migration problem in perovskite films, research has found that it can be solved by interfacial encapsulation, specifically by using dense AlO₂. X Thin films or two-dimensional perovskites can be used to block ion migration and redox reactions at the interface. However, this method can easily lead to the obstruction of charge carrier transport and the accumulation of charge carriers at the interface, which will be detrimental to the transport of charge carriers in the bulk phase and reduce the efficiency of solar cells.

[0051] In addition, the study found that adding potassium chloride can inhibit the migration of ions in the perovskite bulk phase and improve device stability, but the problem of poor perovskite crystal quality has not yet been solved.

[0052] Based on the above analysis, this application provides a perovskite film by adding a chemical formula R-(CH2). nThe passivating material, -CH(NH2)-COOM, contains Lewis base groups in its molecule. The perovskite precursor contains divalent metal ions with two empty orbitals, classifying them as Lewis acids capable of accepting lone pairs of electrons. This passivating material can form Lewis acid-base adducts with the divalent metal ions, slowing down the nucleation and crystallization process and improving crystal quality. Furthermore, the alkali metal ions in the passivating material can form ionic bonds with halide ions in the perovskite material, increasing the activation energy of halide ion migration, inhibiting ion migration, reducing halide vacancy formation, and enhancing the stability of the perovskite film.

[0053] The technical solution of the present invention will now be described in conjunction with the embodiments and accompanying drawings.

[0054] In a first aspect, embodiments of this application disclose a perovskite film comprising a perovskite material with the general chemical formula ABX3 and a perovskite material with the general chemical formula R-(CH2). n Passivation material of -CH(NH2)-COOM.

[0055] In the general chemical formula of perovskite materials, B represents a divalent metal ion, A represents an organic amine cation or a cesium ion, and X represents a halide ion.

[0056] In the general chemical formula of passivation materials, R group represents Lewis base group, M represents alkali metal ion, alkali metal ion can form ionic bond with halide ion, and n is a positive integer less than 5.

[0057] This perovskite film contains perovskite material and has the general chemical formula R-(CH2). n The passivating material, -CH(NH2)-COOM, contains a carbonyl group (-C=O), an amino group (-NH2), and an R group. All three groups are Lewis bases capable of donating lone pairs of electrons. In the general chemical formula for perovskite materials, the B group represents a divalent metal ion with two empty orbitals, belonging to a Lewis acid capable of accepting lone pairs of electrons. All three Lewis base groups can form Lewis acid-base adducts with the divalent metal ion, slowing down the nucleation and crystallization process and improving crystal quality. Furthermore, the alkali metal ions in the passivating material can form ionic bonds with halide ions in the perovskite material, increasing the activation energy of halide ion migration, inhibiting ion migration, reducing halide vacancy formation, and improving the stability of the perovskite film.

[0058] Lewis base passivating agents in related technologies have only one or two Lewis base groups, limiting their effectiveness in improving crystallization quality. This passivating material, through the formation of Lewis acid-base adducts with divalent metal ions using three Lewis base groups, can further slow down the nucleation crystallization process and improve crystallization quality. Furthermore, the aforementioned Lewis base passivating agents generally contain aromatic ring structures such as benzene rings, making them relatively difficult to dissolve in solvents used in the industrial-scale preparation of perovskite films. In contrast, the passivating material in this application is a carbon chain-based passivating material, with the number of carbon atoms n in the carbon chain being a positive integer less than 5. This results in better solubility in solvents used in the industrial-scale preparation of perovskite films, better matching the industrial-scale preparation methods of perovskite films and facilitating large-area, large-scale preparation of perovskite films.

[0059] In summary, this passivation material can improve the crystallinity of the perovskite film, thereby optimizing the crystallization orientation of the perovskite crystals, improving crystallinity, and controlling the band gap. Furthermore, this passivation material can suppress ion migration, enhance the stability of the perovskite material, and thus improve the electrical performance and stability of the perovskite film, further increasing the conversion efficiency of solar cells using this perovskite film.

[0060] Furthermore, in the general chemical formula of this passivation material, the R group represents any one of a carboxyl group, a sulfonic acid group, or a phosphate group. Passivation materials with the above groups have more stable chemical properties and are more likely to form Lewis acid-base adducts with divalent metal ions.

[0061] In the general chemical formula of this passivation material, M represents sodium or potassium ions, which can form strong ionic bonds with halide ions. Based on these strong ionic bonds, halide anions in perovskite materials can be better immobilized, thereby effectively eliminating the corresponding vacancy defects.

[0062] In the general chemical formula of this passivation material, n is 2, meaning that the carbon chain has two carbon atoms. In this case, the passivation material has both good chemical stability and solubility.

[0063] Preferably, the passivation material is monosodium glutamate (MSG) or potassium glutamate (KG). Compared to other passivation materials, MSG and KG have both good solubility and can reduce material costs, meeting the requirements for the industrial manufacturing of perovskite films.

[0064] In some embodiments, the passivation material is doped into the bulk phase of the perovskite film. In other words, the passivation material can be used for bulk passivation of the perovskite film, resulting in a lower defect density inside the perovskite film, better phase distribution uniformity inside the perovskite film, and solar cells with the perovskite film exhibiting superior long-term stability.

[0065] In some embodiments, the passivation material is distributed on the surface of the perovskite film. This passivation material is used to passivate surface defects in the perovskite film, effectively passing off surface defects and contributing to the long-term stable operation of the solar cell.

[0066] In some embodiments, the divalent metal ion is selected from at least one of lead ions or tin ions. The halide ion is selected from at least one of chloride ions, bromide ions, or iodide ions. The organic amine cation is selected from at least one of formamidinium ions or methylamine ions.

[0067] In some embodiments, the thickness of the perovskite film is 400 nm to 1000 nm, including any value within this thickness range, such as 400 nm, 800 nm, or 1000 nm. A perovskite film with this thickness can have good light absorption performance without being too thick, which would result in an excessively long carrier transport distance.

[0068] Secondly, embodiments of this application disclose a method for preparing a perovskite film as described in the first aspect, comprising the following steps:

[0069] A framework layer is prepared on a substrate; wherein the framework layer contains a first precursor material with the general chemical formula BX2, where B represents a divalent metal ion and X represents a halide ion.

[0070] An organic salt solution is coated on the framework layer; wherein the organic salt solution contains a first solvent, a passivating material, and an organic salt with the general chemical formula AX, where A represents an organic amine cation and X represents a halide ion.

[0071] An annealing process was performed on a substrate coated with an organic salt solution to obtain a perovskite film.

[0072] The beneficial effects of this preparation method are explained in detail below:

[0073] The preparation method first prepares a framework layer, and then permeates the framework layer with organic amine cations to form a perovskite material. Due to the good solubility of this passivation material, it can be well dispersed in an organic salt solution. When the organic salt solution is coated on the framework layer, the uniformly dispersed passivation material can react more evenly with the first precursor material in the framework layer. Specifically, the three Lewis base groups in the passivation material form Lewis acid-base adducts with the divalent metal ions in the first precursor material, thereby better slowing down the nucleation and crystallization process and improving the crystal quality.

[0074] Preferably, in the organic salt solution, the molar concentration of the organic amine cation is 0.5 mol / L to 1.5 mol / L, including any value within this molar concentration range, such as 0.5 mol / L, 1 mol / L, or 1.5 mol / L, and the molar concentration of the passivation material is 0.002 mol / L to 0.015 mol / L, including any value within this molar concentration range, such as 0.002 mol / L, 0.007 mol / L, or 0.015 mol / L. Passivation using a passivation material within the above molar concentration range can produce a perovskite film with superior crystal orientation, lower defect density, and higher crystal quality, thereby improving the conversion efficiency of solar cells.

[0075] Preferably, the first solvent is anhydrous ethanol, which meets the requirements for the industrial-scale preparation of perovskite films. The organic salt is selected from at least one of formamidinium hydroiodate, methylamine bromide, or methylamine chloride, and the first precursor material is PbI2. In general, this passivation material is compatible with the industrial-scale preparation method of perovskite films.

[0076] For example, the substrate includes a bottom cell and an intermediate composite layer and a hole transport layer sequentially stacked on the top surface of the bottom cell. In the step of preparing the framework layer on the substrate, the framework layer is prepared by vapor deposition. In the step of coating the framework layer with an organic salt solution, the coating method is selected from any one of spin coating, blade coating, or slot coating.

[0077] Thirdly, embodiments of this application disclose a method for preparing a perovskite film as described in the first aspect, comprising the following steps:

[0078] A wet film is prepared by coating a perovskite precursor solution onto a substrate; wherein the perovskite precursor solution comprises a second solvent, a passivation material, and a second precursor material.

[0079] The solvent on the surface of the wet film is removed, and the perovskite film is obtained by annealing and crystallization.

[0080] The beneficial effects of this preparation method are explained in detail below:

[0081] This preparation method yields perovskite films in a one-step process, which is simple, fast, and produces high-purity perovskite materials. However, the one-step method can lead to numerous crystal defects in the perovskite film. This application addresses this by incorporating a passivating material, effectively improving the crystallinity of the perovskite film, thus combining the advantages of a simple preparation process with high-quality crystallinity.

[0082] Preferably, in the perovskite precursor solution, the molar concentration of the passivation material is 0.002 mol / L to 0.015 mol / L, including any value within this molar concentration range, such as 0.002 mol / L, 0.007 mol / L, or 0.015 mol / L, and the molar concentration of the second precursor material is 1 mol / L to 1.2 mol / L, including any value within this molar concentration range, such as 1 mol / L, 1.1 mol / L, or 1.2 mol / L. Passivation using passivation materials within the above molar concentration range can produce perovskite films with superior crystal orientation, lower defect density, and higher crystal quality, thereby obtaining solar cells with high conversion efficiency.

[0083] Preferably, the second precursor material is FAPbI3. The second solvent is dimethylformamide. Both of these materials are used in the industrial-scale preparation process of perovskite films. In other words, this passivation material is compatible with the industrial-scale preparation method of perovskite films, exhibiting better versatility.

[0084] Fourthly, embodiments of this application disclose a method for preparing a perovskite film as described in the first aspect, comprising the following steps:

[0085] Prepare perovskite films containing perovskite materials;

[0086] A passivation material solution is coated on the surface of a perovskite film; wherein the passivation material solution contains a passivation material and a third solvent.

[0087] The beneficial effects of this preparation method are explained in detail below:

[0088] This preparation method uses solution coating to passivate the surface of the perovskite film, making the operation simpler.

[0089] Preferably, the concentration of the passivating material in the passivating material solution is 0.8 mg / mL to 1.2 mg / mL. The coating amount of the passivating material solution is 20 μL / cm. 2 ~40μL / cm 2 This includes any value within the coating amount range, for example, 20 μL / cm. 2 30μL / cm 2 or 40 μL / cm 2 The above-mentioned amount of passivating material solution can effectively passivate the surface of the perovskite film.

[0090] Preferably, the third solvent is isopropanol. Isopropanol is a solvent that meets the requirements for the industrial-scale preparation of perovskite films. Therefore, this passivation material is compatible with the industrial-scale preparation method of perovskite films.

[0091] Fifthly, refer to Figure 1This application discloses a solar cell 100, including a first carrier transport layer, a second carrier transport layer, and a perovskite film 104 as described in the first aspect, or a perovskite film 104 prepared according to the preparation methods described in the second, third, or fourth aspects. The conversion efficiency and stability of the solar cell 100 having this perovskite film 104 are improved.

[0092] The first carrier transport layer and the second carrier transport layer are respectively disposed on two opposite surfaces of the perovskite film 104; one of the two layers is an electron transport layer 105 and the other is a hole transport layer 103.

[0093] Furthermore, the solar cell 100 also includes a bottom cell 101, an intermediate composite layer 102, a composite electron transport layer 106, a barrier layer 107, and an electrode 108.

[0094] The bottom cell 101 has a top surface, and an intermediate composite layer 102, a hole transport layer 103, a perovskite film 104, an electron transport layer 105, a composite electron transport layer 106, a barrier layer 107, and an electrode 108 are sequentially stacked on the top surface in a direction away from the bottom cell 101.

[0095] For example, the bottom cell 101 can be a heterojunction solar cell 100 or a passivated contact solar cell 100. The material of the intermediate composite layer 102 can be a transparent conductive oxide such as indium tin oxide (ITO), indium-doped zinc oxide (IZO), or indium-doped tungsten oxide (IWO). The intermediate composite layer 102 can be prepared by solution spin coating or magnetron sputtering. The material of the hole transport layer 103 can be NiOX, self-assembled single-molecule (SAM) material, or poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA). The material of the electron transport layer 105 can be fullerene (C60). The material of the composite electron transport layer 106 can be tin oxide (SnO2), and the composite electron transport layer 106 is also used to block holes, with a film thickness of 8 nm to 20 nm. The material of the blocking layer 107 can be indium tin oxide (ITO), and it is also used for energy level modulation to reduce redox reactions caused by carrier recombination and ion migration. The electrode 108 can be made of silver and has a thickness of 80 nm to 120 nm.

[0096] The solar cell 100 is a tandem cell, and its top cell has the aforementioned perovskite film 104, which improves the conversion efficiency and stability of the tandem cell.

[0097] Sixthly, embodiments of this application disclose a photovoltaic module, including a plurality of solar cells connected in series and / or in parallel, wherein at least one solar cell is the solar cell described in the fifth aspect.

[0098] The performance of the perovskite film and solar cell prepared in this application will be described below with reference to the embodiments and test data.

[0099] Example 1

[0100] This embodiment of a method for preparing a solar cell includes the following steps:

[0101] S1. Fabrication of the framework layer on the substrate: The substrate includes a bottom cell and an intermediate composite layer and a hole transport layer sequentially stacked on the top surface of the bottom cell. The bottom cell is a heterojunction solar cell with an area of ​​2.5cm × 2.5cm, the intermediate composite layer is an indium tin oxide (ITO) layer, and the hole transport layer is NiO. X Layers. A 600 nm thick PbI2 layer and a 60 nm thick CsBr layer were prepared on the side of the hole transport layer away from the bottom cell using a dual-source evaporation method as a framework layer.

[0102] S2. Coating the framework layer with an organic salt solution: Dissolve 40 mg formamidin hydroiodide (FAI), 12 mg methylamine bromide (MABr), 12 mg methylamine chloride (MACl), and 0.5 mg sodium glutamate in 1 mL of anhydrous ethanol to obtain an organic salt solution. In this organic salt solution, the molar concentration of sodium glutamate is 0.003 mol / L, and the total molar concentration of methylamine ions and formamidin ions is 0.507 mol / L. Take 100 μL of the organic salt solution and drop it onto the substrate for dynamic spin-coating onto the framework layer. The spin-coating parameters are 200 rpm / s.

[0103] S3. Annealing the substrate coated with organic salt solution to obtain a perovskite film: The spin-coated substrate is placed on a 150°C hot metal plate and annealed for 15 minutes to obtain a perovskite film.

[0104] S4. Preparation of electron transport layer: A fullerene (C60) with a thickness of 20 nm is deposited on the side of the perovskite film away from the bottom cell by physical vapor deposition (PVD) as an electron transport layer.

[0105] S5. Preparation of composite electron transport layer: A 14 nm thick tin oxide (SnO2) layer is deposited on the side of the electron transport layer away from the bottom cell by atomic vapor deposition (ALD) as a composite electron transport layer.

[0106] S6. Preparation of the barrier layer: A 5 nm thick indium tin oxide (ITO) layer is deposited on the side of the barrier layer away from the bottom cell by magnetron sputtering.

[0107] S7. Electrode fabrication: A 100 nm thick layer of silver is deposited as an electrode on the side of the barrier layer away from the bottom cell by physical vapor deposition (PVD).

[0108] Example 2

[0109] This embodiment of a method for preparing a solar cell includes the following steps:

[0110] S1. Preparation of a wet film by coating a perovskite precursor solution onto a substrate: The substrate includes a bottom cell and an intermediate composite layer and a hole transport layer sequentially stacked on the top surface of the bottom cell. The bottom cell is a heterojunction solar cell with an area of ​​2.5cm × 2.5cm, the intermediate composite layer is an indium tin oxide (ITO) layer, and the hole transport layer is NiO. X Perovskite precursor solution was prepared by dissolving 1.1 mmol FAPbI3 and 0.005 mmol sodium glutamate in 1 mL dimethylformamide (DMF). A wet film was prepared by spin-coating the perovskite precursor solution onto the side of the hole transport layer opposite to the bottom cell.

[0111] S2. Remove the solvent from the surface of the wet film and crystallize it by annealing to obtain a perovskite film: Remove the solvent from the surface of the wet film by nitrogen purging and then crystallize it by thermal annealing to obtain a perovskite film.

[0112] S3. Preparation of electron transport layer: A fullerene (C60) with a thickness of 20 nm is deposited on the side of the perovskite film away from the bottom cell by physical vapor deposition (PVD) as an electron transport layer.

[0113] S4. Preparation of composite electron transport layer: A tin oxide (SnO2) layer with a thickness of 8-20 nm is deposited on the side of the electron transport layer away from the bottom cell by atomic vapor deposition (ALD) as a composite electron transport layer.

[0114] S5. Preparation of the barrier layer: A 5 nm thick indium tin oxide (ITO) layer is deposited on the side of the barrier layer away from the bottom cell by magnetron sputtering.

[0115] S6. Electrode fabrication: A silver layer with a thickness of 80-120 nm is deposited on the side of the barrier layer away from the bottom cell by physical vapor deposition (PVD) as an electrode.

[0116] Example 3

[0117] This embodiment of a method for preparing a solar cell includes the following steps:

[0118] S1. Fabrication of the framework layer on the substrate: The substrate includes a bottom cell and an intermediate composite layer and a hole transport layer sequentially stacked on the top surface of the bottom cell. The bottom cell is a heterojunction solar cell with an area of ​​2.5cm × 2.5cm, the intermediate composite layer is an indium tin oxide (ITO) layer, and the hole transport layer is NiO. XLayers. A 600 nm thick PbI2 layer and a 60 nm thick CsBr layer were prepared on the side of the hole transport layer away from the bottom cell using a dual-source evaporation method as a framework layer.

[0119] S2. Coating the framework layer with an organic salt solution: Dissolve 40 mg formamidin hydroiodate (FAI), 12 mg methylamine bromide (MABr), and 12 mg methylamine chloride (MACl) in 1 mL of anhydrous ethanol to obtain an organic salt solution, wherein the sum of the molar concentrations of methylamine ions and formamidin ions in this organic salt solution is 0.507 mol / L. Take 100 μL of the organic salt solution and add it dropwise onto the substrate for dynamic spin-coating onto the framework layer at a spin-coating parameter of 200 rpm / s.

[0120] S3. Annealing the substrate coated with organic salt solution to obtain a perovskite film: The spin-coated substrate is placed on a 150°C hot metal plate and annealed for 15 minutes to obtain a perovskite film.

[0121] S4. Coating the perovskite film surface with a passivation material solution: Dissolve sodium glutamate in isopropanol to prepare a passivation material solution with a concentration of 1 mg / mL. (30 μL / cm) 2 A passivating material solution is coated onto the surface of the perovskite film.

[0122] S5. Preparation of electron transport layer: A fullerene (C60) with a thickness of 20 nm is deposited on the side of the perovskite film away from the bottom cell by physical vapor deposition (PVD) as an electron transport layer.

[0123] S6. Preparation of composite electron transport layer: A tin oxide (SnO2) layer with a thickness of 8-20 nm is deposited on the side of the electron transport layer away from the bottom cell by atomic vapor deposition (ALD) as a composite electron transport layer.

[0124] S7. Preparation of the barrier layer: A 5 nm thick indium tin oxide (ITO) layer is deposited on the side of the barrier layer away from the bottom cell by magnetron sputtering.

[0125] S8. Electrode fabrication: A silver layer with a thickness of 80-120 nm is deposited on the side of the barrier layer away from the bottom cell by physical vapor deposition (PVD) as an electrode.

[0126] Example 4

[0127] The only difference between this embodiment and Embodiment 1 is that the amount of sodium glutamate used in step S2 is 0.1 mg.

[0128] Example 5

[0129] The only difference between this embodiment and Embodiment 1 is that the amount of sodium glutamate used in step S2 is 3 mg.

[0130] Comparative Example 1

[0131] The only difference between Comparative Example 1 and Example 1 is that sodium glutamate was not added to the organic salt solution in step S2.

[0132] Comparative Example 2

[0133] The only difference between Comparative Example 2 and Example 1 is that in step S2, sodium glutamate was not added to the organic salt solution, but 0.5 mg of potassium chloride was added.

[0134] Comparative Example 3

[0135] The only difference between Comparative Example 2 and Example 1 is that in step S2, sodium glutamate was not added to the organic salt solution, but 0.5 mg of potassium 4-sulfobenzoic acid monophosphate was added.

[0136] Scanning Electron Microscope (SEM) Images

[0137] The surfaces of the perovskite films prepared in step S3 of Example 1 and Comparative Example 1 were imaged using a scanning electron microscope. Figure 2 and Figure 3 By comparison Figure 2 and Figure 3 Comparative Example 1, due to the absence of passivating material, exhibited a faster crystallization rate, resulting in smaller perovskite crystal particles and a smoother perovskite film surface. The reaction... Figure 2 The brightness is relatively consistent across different areas. In Example 1, sodium glutamate was added as a passivating material. The three Lewis base groups in the molecule of this passivating material can all form Lewis acid-base adducts with lead ions, slowing down the nucleation and crystallization process, improving the crystal quality, and resulting in larger perovskite film crystal particles. This makes the surface of the perovskite film in Example 1 rougher than that in Comparative Example 1, which is reflected in… Figure 3 The brightness varies considerably in different parts of the body. Figure 3 There are many brighter areas in the middle.

[0138] Solar cell performance testing

[0139] The performance of the solar cells prepared in each embodiment and comparative example was tested, and the test results are shown in Table 1.

[0140] Table 1: Test Results of Solar Cells

[0141]

[0142] Please refer to Table 1. The test results are analyzed below:

[0143] Analysis of the test results for Examples 1, 4, and 5 shows that the optimal addition amount of monosodium glutamate (MSG) in the perovskite precursor solution is between 0.5 mg / mL and 1.5 mg / mL. In Example 4, the trace amount of MSG had a negligible effect on improving the perovskite film, resulting in a minimal performance improvement in the solar cell. Consequently, the open-circuit voltage, short-circuit current, fill factor, conversion efficiency, and parallel resistance of Example 4 were all lower than those of Example 1, while the series resistance was higher. In Example 5, excessive MSG reduced the performance improvement. Excessive MSG doping affected the crystallization of the perovskite, and the MSG filling the grain boundaries hindered grain growth. The MSG remaining in the perovskite bulk phase reduced the electrical performance of the perovskite film, resulting in the open-circuit voltage, short-circuit current, fill factor, conversion efficiency, and parallel resistance of Example 5 being lower than those of Example 1, while the series resistance was higher.

[0144] In Example 1, the addition of an appropriate amount of monosodium glutamate (MSG) improves the crystallinity of the perovskite film, thereby optimizing the crystal orientation of the perovskite crystals, enhancing crystallinity, and regulating the band gap. This passivation material also inhibits ion migration, improves the stability of the perovskite material, and thus enhances the electrical performance and stability of the perovskite film, further improving the conversion efficiency of solar cells with this perovskite film.

[0145] Analysis of the test results of Examples 2 and 3 and Comparative Example 1 shows that the performance of solar cells prepared by monosodium glutamate using the one-step preparation method of Example 2 and the surface passivation method of Example 3 is significantly improved compared with Comparative Example 1, indicating that the passivation material is suitable for both the one-step method and the surface passivation method.

[0146] Analysis of the test results of Example 1 and Comparative Example 1 shows that, in Comparative Example 1, since no passivating material was added, the crystallization orientation and crystallization rate of the perovskite were uncontrolled, resulting in poor crystallization quality of the perovskite film. The perovskite film had problems such as high defect density and non-uniform composition, which in turn led to the solar cell's open-circuit voltage, short-circuit current, fill factor, conversion efficiency and parallel resistance being lower than those of Example 1, and the series resistance being higher than that of Example 1.

[0147] Analysis of the test results of Example 1 and Comparative Example 2 shows that although potassium chloride was added as a bulk additive in Comparative Example 2 to inhibit the migration of perovskite ions, it did not improve the crystal quality of perovskite. The crystal quality of the perovskite film was poor, which resulted in the open-circuit voltage, short-circuit current, fill factor, conversion efficiency and parallel resistance of the solar cell being lower than those of Example 1, and the series resistance being higher than that of Example 1.

[0148] Analysis of the test results of Example 1 and Comparative Example 3 shows that although potassium 4-sulfobenzoic acid was added as a bulk additive in Comparative Example 3, only two groups in potassium 4-sulfobenzoic acid can combine with lead ions, namely carboxyl and sulfonate groups. This bulk additive has limited effect on improving the performance of solar cells, resulting in the open circuit voltage, short circuit current, fill factor, conversion efficiency and parallel resistance of Comparative Example 3 being lower than those of Example 1, and the series resistance being higher than that of Example 1.

[0149] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A perovskite film, characterized in that, This includes perovskite materials with the general chemical formula ABX3 and materials with the general chemical formula R-(CH2). n Passivation materials for -CH(NH2)-COOM; In the general chemical formula of the perovskite material, B represents a divalent metal ion, A represents an organic amine cation or a cesium ion, and X represents a halide ion; In the chemical formula of the passivation material, R group represents Lewis base group, M represents alkali metal ion, the alkali metal ion can form ionic bond with the halide ion, and n is a positive integer less than 5.

2. The perovskite film according to claim 1, characterized in that, In the chemical formula of the passivation material, R group represents any one of carboxyl group, sulfonic acid group or phosphate group, M represents sodium ion or potassium ion, and n is 2.

3. The perovskite film according to claim 2, characterized in that, The passivation material is sodium glutamate or potassium glutamate.

4. The perovskite film according to claim 1, characterized in that, The passivation material is doped into the bulk phase of the perovskite film.

5. The perovskite film according to claim 1, characterized in that, The passivating material is distributed on the surface of the perovskite film.

6. The perovskite film according to any one of claims 1 to 5, characterized in that, The divalent metal ion is selected from at least one of lead ions or tin ions; And / or, the halide ion is selected from at least one of chloride ions, bromide ions, or iodide ions; And / or, the organic amine cation is selected from at least one of formamidinium ion or methylamine ion; And / or, the thickness of the perovskite film is 400 nm to 1000 nm.

7. A method for preparing a perovskite film as described in any one of claims 1 to 6, characterized in that, Includes the following steps: A framework layer is prepared on a substrate; wherein the framework layer contains a first precursor material with the general chemical formula BX2, wherein in the general chemical formula of the first precursor material, B represents a divalent metal ion and X represents a halide ion. An organic salt solution is coated on the skeleton layer; wherein the organic salt solution comprises a first solvent, the passivation material, and an organic salt with the general chemical formula AX, wherein A represents an organic amine cation and X represents a halide ion. The substrate coated with the organic salt solution is annealed to obtain the perovskite film.

8. The method for preparing a perovskite film according to claim 7, characterized in that, In the organic salt solution, the molar concentration of the organic amine cation is 0.5 mol / L to 1.5 mol / L, and the molar concentration of the passivation material is 0.002 mol / L to 0.015 mol / L. And / or, the first solvent is anhydrous ethanol; And / or, the organic salt is selected from at least one of formamidin hydroiodate, methylamine bromide, or methylamine chloride; And / or, the first precursor material is PbI2.

9. A method for preparing a perovskite film as described in any one of claims 1 to 6, characterized in that, Includes the following steps: A wet film is prepared by coating a perovskite precursor solution onto a substrate; wherein the perovskite precursor solution comprises a second solvent, the passivation material, and a second precursor material; The solvent on the surface of the wet film is removed, and the perovskite film is obtained by annealing and crystallization treatment.

10. The method for preparing a perovskite film according to claim 9, characterized in that, In the perovskite precursor solution, the molar concentration of the passivation material is 0.002 mol / L to 0.015 mol / L, and the molar concentration of the second precursor material is 1 mol / L to 1.2 mol / L. And / or, the second precursor material is FAPbI3; And / or, the second solvent is dimethylformamide.

11. A method for preparing a perovskite film as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Prepare the perovskite film containing the perovskite material; A passivation material solution is coated on the surface of the perovskite film; wherein the passivation material solution contains the passivation material and a third solvent.

12. The method for preparing a perovskite film according to claim 11, characterized in that, The concentration of the passivating material in the passivating material solution is 0.8 mg / mL to 1.2 mg / mL, and the coating amount of the passivating material solution is 20 μL / cm. 2 ~40μL / cm 2 ; And / or, the third solvent is isopropanol.

13. A solar cell, characterized in that, It includes a first carrier transport layer, a second carrier transport layer, and a perovskite film as described in any one of claims 1 to 6, or a perovskite film prepared by any one of claims 7 to 12; The first carrier transport layer and the second carrier transport layer are respectively disposed on two opposite surfaces of the perovskite film; one of the two carrier transport layers is an electron transport layer and the other is a hole transport layer.

14. The solar cell according to claim 13, characterized in that, The solar cell also includes a bottom cell, an intermediate composite layer, a composite electron transport layer, a barrier layer, and electrodes; The bottom cell has a top surface, and the intermediate composite layer, the hole transport layer, the perovskite film, the electron transport layer, the composite electron transport layer, the blocking layer, and the electrode are sequentially stacked on the top surface in a direction away from the bottom cell.

15. A photovoltaic module, characterized in that, It includes a plurality of solar cells connected in series and / or in parallel, at least one of the solar cells being the solar cell of claim 13 or 14.

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