Preparation method of perovskite precursor solution, perovskite solar cell and its fabrication method

Abstract

This invention discloses a method for preparing a perovskite precursor solution, a perovskite solar cell, and a method for preparing the same, relating to the field of cell fabrication technology. The method for preparing the perovskite precursor solution includes: based on the composition Cs of the perovskite material... 0.05 FA 0.85 MA 0.1 PbI3 was used to determine several substances and their contents for synthesizing perovskite materials. These substances were then dissolved to obtain a first solution. A crystallization aid was dissolved in the first solution to obtain a second solution. Diamine hydrobromide was dissolved in the second solution to obtain a perovskite precursor solution. This method allows for the preparation of a perovskite precursor solution for defect elimination, which is beneficial for eliminating defects in the perovskite layer and thus improving the efficiency and stability of perovskite solar cells.

Description

Technical Field

[0001] This invention relates to the field of battery fabrication technology, and in particular to a method for preparing a perovskite precursor solution, a perovskite solar cell, and a method for fabricating a perovskite solar cell. Background Technology

[0002] Organic-inorganic hybrid perovskites, as novel photoactive materials, possess excellent photovoltaic properties such as high light absorption coefficient, superior carrier mobility, low hysteresis, low production cost, and adjustable bandgap, making them of broad research value and application prospects in the field of solar cells.

[0003] Currently, while perovskite solar cells boast high efficiency, they suffer from poor stability due to numerous defects within the perovskite layer. However, these defects are difficult to avoid in polycrystalline materials; therefore, reducing defects in the perovskite active layer can improve the performance and stability of perovskite solar cells. Summary of the Invention

[0004] This invention provides a method for preparing a perovskite precursor solution, a perovskite solar cell, and a method for preparing the same. The method can produce a perovskite precursor solution for eliminating defects, which is beneficial for eliminating defects in the perovskite layer, thereby improving the efficiency and stability of the perovskite solar cell.

[0005] In a first aspect, the present invention provides a method for preparing a perovskite precursor solution, the method comprising:

[0006] Based on the composition of perovskite materials Cs 0.05 FA 0.85 MA 0.1 PbI3 was used to determine the substances and their contents used in the synthesis of perovskite materials, and the substances were dissolved to obtain a first solution.

[0007] The crystallization aid is dissolved in the first solution to obtain the second solution;

[0008] Diamine hydrobromide was dissolved in a second solution to obtain a perovskite precursor solution.

[0009] Secondly, the present invention provides a method for preparing a perovskite solar cell, the method comprising:

[0010] Provide transparent conductive glass substrates;

[0011] A hole transport layer is prepared on the transparent conductive glass substrate;

[0012] A self-contained monolayer was prepared on the hole transport layer.

[0013] A perovskite layer was prepared on the self-assembled monolayer using a perovskite precursor solution, wherein the perovskite precursor solution was prepared using the method described above.

[0014] An electron transport layer is fabricated on the perovskite layer to obtain a pre-fabricated device.

[0015] Metal electrodes are fabricated on the prefabricated device to obtain a perovskite solar cell.

[0016] Thirdly, the present invention provides a perovskite solar cell, which is prepared by using the above-described method for preparing perovskite solar cells.

[0017] This invention provides a method for preparing a perovskite precursor solution, a perovskite solar cell, and a method for preparing the same, based on the composition Cs of the perovskite material. 0.05 FA 0.85 MA 0.1 PbI3 was used to determine several substances and their contents for synthesizing perovskite materials. These substances were then dissolved to obtain a first solution. A crystallization aid was dissolved in the first solution to obtain a second solution. Diamine hydrobromide was dissolved in the second solution to obtain a perovskite precursor solution. This perovskite precursor solution can eliminate defects in the perovskite crystal structure, which is beneficial for eliminating defects in the perovskite layer and thus improving the photoelectric performance, efficiency, and stability of perovskite solar cells. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic flowchart illustrating the steps of a method for preparing a perovskite precursor solution provided in an embodiment of this application;

[0020] Figure 2 This is a schematic diagram of the structure of ODADBr provided in an embodiment of this application;

[0021] Figure 3 This is a schematic diagram of the structure of HDADBr provided in an embodiment of this application;

[0022] Figure 4 A schematic flowchart illustrating the steps of a method for fabricating a perovskite solar cell provided in this application embodiment;

[0023] Figure 5A schematic diagram of a pure hole device structure and a schematic diagram of defect state density provided for embodiments of this application;

[0024] Figure 6 A schematic diagram of a purely electronic device structure and a schematic diagram of defect state density are provided for embodiments of this application;

[0025] Figure 7(a) is a schematic diagram of the crystallinity characterization of a perovskite solar cell provided in an embodiment of this application;

[0026] Figure 7(b) is a schematic diagram of the crystallinity characterization of another perovskite solar cell provided in the embodiments of this application;

[0027] Figure 8(a) is a SEM image of a perovskite solar cell prepared from the perovskite precursor solution provided in the control group of the present application.

[0028] Figure 8(b) is a SEM image of the perovskite solar cell prepared from the perovskite precursor solution provided in Example 1 of this application.

[0029] Figure 8(c) is a SEM image of the perovskite solar cell prepared from the perovskite precursor solution provided in Example 2 of this application.

[0030] Figure 8(d) shows the crystal size distribution of perovskite solar cells prepared from the control group provided in the embodiments of this application and the perovskite precursor solutions provided in each embodiment;

[0031] Figure 9(a) is an AFM morphology diagram of the perovskite solar cell prepared from the perovskite precursor solution provided in the control group of the present application.

[0032] Figure 9(b) is an AFM morphology diagram of the perovskite solar cell prepared from the perovskite precursor solution provided in Example 1 of this application.

[0033] Figure 9(c) is an AFM morphology diagram of the perovskite solar cell prepared from the perovskite precursor solution provided in Example 2 of this application.

[0034] Figure 10 A schematic diagram of the photoelectric performance JV curve and Nyquist plot of a perovskite solar cell provided for embodiments of this application;

[0035] Figure 11(a) is a schematic diagram of the JV for the highest efficiency of a perovskite solar cell provided in an embodiment of this application;

[0036] Figure 11(b) is a schematic diagram of the cell efficiency of another perovskite solar cell provided in the embodiments of this application;

[0037] Figure 11(c) is a schematic diagram of the cell efficiency of another perovskite solar cell provided in the embodiment of this application;

[0038] Figure 12(a) is a schematic diagram of the stability performance of a perovskite solar cell provided in an embodiment of this application;

[0039] Figure 12(b) is a schematic diagram of another performance regarding the stability of perovskite solar cells provided in an embodiment of this application. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0042] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0043] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0044] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0045] The chemical formula for the perovskite crystal structure is ABX3. This structure has A-site cation defects and X-site anion defects, which lead to low efficiency and poor stability of perovskite solar cell devices.

[0046] This invention provides a method for preparing a perovskite precursor solution, a perovskite solar cell, and a method for preparing the same, based on the composition Cs of the perovskite material. 0.05 FA 0.85 MA0.1 PbI3 was used to determine several substances and their contents for synthesizing perovskite materials. These substances were then dissolved to obtain a first solution. A crystallization aid was dissolved in the first solution to obtain a second solution. Diamine hydrobromide was dissolved in the second solution to obtain a perovskite precursor solution. This perovskite precursor solution can eliminate defects in the perovskite crystal structure, which is beneficial for eliminating defects in the perovskite layer and thus improving the photoelectric performance, efficiency, and stability of perovskite solar cells.

[0047] See Figure 1 , Figure 1 This is a schematic flowchart of a method for preparing a perovskite precursor solution according to an embodiment of this application. The preparation method includes steps S101 to S103.

[0048] Step S101: Based on the composition Cs of the perovskite material 0.05 FA 0.85 MA 0.1 PbI3 was used to determine the composition and content of several substances used in the synthesis of perovskite materials, and the substances were dissolved to obtain a first solution.

[0049] The first solution is a solution formed by dissolving multiple substances used to synthesize perovskite materials.

[0050] In the embodiments of this application, the components of the perovskite material include Cs. 0.05 FA 0.85 MA 0.1 PbI3 is used to determine the multiple substances needed for synthesizing perovskite materials based on this composition. The required content of each substance can be calculated by considering the amount of perovskite material to be synthesized. In this way, stable perovskite crystals with accurate stoichiometry can be obtained. Then, the multiple substances are dissolved in a solvent to obtain the first solution.

[0051] In some embodiments, the plurality of substances respectively include: Pb I2 (lead iodide), FAI (formamidinium hydroiodate, also known as formamidinium iodide), MAI (methylamine iodide), and Cs I (cesium iodide). The plurality of substances used in the synthesis of perovskite materials in the embodiments of this application are readily available and common in the market.

[0052] In some embodiments, multiple substances are dissolved in a mixed solvent of DMF (dimethylformamide) and DMSO (dimethyl sulfoxide) to obtain a first solution.

[0053] Common solvents used to prepare perovskite precursor solutions include dimethylformamide (DMF), gamma-butyrolactone (GBL), dimethyl sulfoxide (DMSO), and N,N-dimethylacetamide (DMA). These polar solvents can be removed by thermal annealing or drying in air or an inert atmosphere. During solvent removal, the perovskite material becomes supersaturated, leading to nucleation and crystal growth. This method is a simple and easy-to-implement solvent evaporation method for perovskite deposition. In the embodiments of this application, a mixed solvent of DMF and DMSO is used to prepare the perovskite precursor solution.

[0054] For example, since the composition of perovskite materials is Cs 0.05 FA 0.85 MA 0.1 Therefore, 760.7 mg of Pb I2, 219.3 mg of FAI, 23.8 mg of MA I, and 19.5 mg of Cs I can be dissolved in 1 ml of a mixed solvent of DMF and DMSO, with the ratio of DMF to DMSO being 4:1. The solution is stirred at room temperature for 12 hours to dissolve the above substances in the mixed solvent of DMF and DMSO, thus obtaining the first solution.

[0055] Step S102: Dissolve the crystallization aid in the first solution to obtain the second solution.

[0056] The crystallization aid can be a material used to assist crystallization, such as MAC l (methylammonium chloride). The second solution can be the first solution to which the crystallization aid has been added.

[0057] Perovskite precursor solutions are typically colloidal dispersions, not true solutions. More specifically, perovskite precursor solutions are colloids formed by a stable colloidal framework; this lead-based polyhalide framework is formed by the sharing of halogen atoms between inorganic and organic components in the precursor through coordination. The morphology and size of this framework determine the morphology and grain size of the perovskite after spin-coating and annealing. When the crystallization aid MAC l (methylammonium chloride) is added, the tetragonal framework is retained and further grown, and the framework becomes more stable. During annealing, MAC l has higher volatility and a larger interplanar spacing of the framework, accelerating the crystallization process. Therefore, adding the additive MAC l when preparing the perovskite precursor solution can control the perovskite crystallization process and improve the crystal morphology of perovskite. Perovskite films with specific crystal orientations obtained by post-treatment with MAC l can significantly improve the performance of perovskite solar cells and increase the photoelectric conversion efficiency (PCE) of perovskite solar cells.

[0058] Step S103: Dissolve diamine hydrobromide in the second solution to obtain a perovskite precursor solution.

[0059] Because the chemical formula for the perovskite crystal structure is ABX3, this structure contains A-site cation defects and X-site anion defects. These defects lead to low efficiency and poor stability in perovskite solar cell devices. The diamine hydrobromide provided in this application can be used as a passivating agent. Specifically, the cations in the diamine hydrobromide can fill the A-site cation defects, and the bromide ions can fill the X-site anion defects. Therefore, adding diamine hydrobromide to the perovskite precursor solution can reduce defects, thereby improving the photoelectric performance, efficiency, and stability of perovskite solar cells.

[0060] In some embodiments, the molar fraction percentage of diamine hydrobromide is 0.04-0.12 mol%.

[0061] For example, the mass of diamine hydrobromide is related to the concentration of the first solution. Generally, the mass of diamine hydrobromide is 0.04-0.12 mol% of the concentration of the first solution, such as 0.04 mol%, 0.08 mol%, and 0.12 mol%. Preferably, the perovskite precursor solution is most effective at eliminating defects when the mass of diamine hydrobromide is 0.08 mol% of the concentration of the first solution.

[0062] In some embodiments, the carbon chain length of diamine hydrobromide is 6-8 carbon atoms.

[0063] Among them, a carbon chain is a long, non-cyclic chain formed by carbon atoms connected to each other by single, double, or triple bonds.

[0064] Specifically, when the carbon chain length is 6-8 carbon atoms, diamine hydrobromide has a positive effect on eliminating defects; if the carbon chain length is too short or too long, diamine hydrobromide has a negative effect on eliminating defects.

[0065] In some embodiments, the diamine hydrobromide may be selected from one or more of 1,8-octanediamine hydrobromide (ODADBr) and 1,6-hexanediamine hydrobromide (HDADBr).

[0066] like Figure 2 and Figure 3 As shown, both 1,8-octanediamine hydrobromide (ODADBr) and 1,6-hexanediamine hydrobromide (HDADBr) contain cations, which can fill the defects of the A-site cations in the perovskite crystal structure. They also contain bromide ions, which can fill the defects of the X-site anions in the perovskite crystal structure.

[0067] For example, 12.5 mol% MAC l can be added to the first solution and stirred at room temperature for 2 hours to obtain a second solution. Then, 0.08 mol% ODADBr or HDADBr can be added to the second solution and stirred until completely dissolved to obtain a perovskite precursor solution.

[0068] For example, 0.08 mol% of ODADBr or HDADBr is added to the second solution and stirred until completely dissolved. The solution is then filtered using a nylon filter membrane (0.45 μm pore size). The filtered solution is aged at room temperature for 4 hours to obtain the perovskite precursor solution.

[0069] See Figure 4 , Figure 4 This is a schematic flowchart of an embodiment of the fabrication method of perovskite solar cells according to this application. The fabrication method includes steps S201 to S206.

[0070] Step S201: Provide a transparent conductive glass substrate.

[0071] The transparent conductive glass substrate is typically made of conductive glass coated with tin oxide (SnO2), indium tin oxide (ITO), or fluorine-doped tin oxide (FTO). It possesses excellent transparency and conductivity, making it suitable as a light transmission medium and a bottom electrode.

[0072] For example, an ITO (size, 20*16*0.7mm) transparent conductive glass substrate can be selected. The transparent conductive glass substrate is washed with soapy water and rinsed with deionized water. Subsequently, the transparent conductive glass substrate is ultrasonically cleaned in deionized water and ethanol for 30 minutes in sequence. The cleaned transparent conductive glass substrate is placed in a vacuum drying oven and dried at 80°C for 12 hours. Then, the surface of the transparent conductive glass substrate is subjected to plasma treatment for 3 minutes to enhance the wettability of the transparent conductive glass substrate surface.

[0073] Step S202: A hole transport layer is prepared on a transparent conductive glass substrate.

[0074] The hole transport layer is located on a transparent conductive glass substrate, and the material used to fabricate the hole transport layer can include materials such as nickel oxide. The hole transport layer possesses excellent hole transport characteristics and photostability, which helps to improve hole collection efficiency and transport speed.

[0075] For example, 1 ml of deionized water was added to 15 mg of nickel oxide and sonicated for 10 min to form a nickel oxide dispersion. The nickel oxide dispersion was then filtered through a nylon filter membrane (pore size 0.45 μm) to obtain a nickel oxide dispersion with good dispersibility. 80 μL of the nickel oxide dispersion was dropped onto an ITO glass substrate cooled to room temperature, spin-coated at 2000 rpm for 30 s, and then transferred to a hot stage at 150 °C for annealing for 20 min to form a nickel oxide thin film, i.e., a hole transport layer, on the surface of the ITO glass substrate.

[0076] Step S203: Prepare a self-contained monolayer on the hole transport layer.

[0077] The self-assembled monolayer is located on the hole transport layer, and the materials used to prepare the self-assembled monolayer can include materials such as (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz). The self-assembled monolayer can form a uniform, dense, and ordered molecular layer on the surface of the hole transport layer. This structural characteristic significantly improves the surface properties of the hole transport layer. For example, it can enhance the corrosion resistance, wear resistance, and photoelectric properties of the hole transport layer.

[0078] For example, 1 ml of anhydrous ethanol was added to 0.5 mg Me-4PACz, and the mixture was stirred at room temperature for 12 hours. The solution was then filtered through a nylon membrane (0.45 μm pore size). 100 μl of the filtered solution was dropped onto the surface of the hole transport layer, spin-coated at 4000 rpm for 30 s, and then transferred to a hot plate at 100 °C for annealing for 10 min to allow the self-assembled monomolecules to anchor on the surface of the hole transport layer.

[0079] Step S204: A perovskite layer is prepared on a self-assembled monolayer using a perovskite precursor solution. The perovskite precursor solution is prepared using the same method as the perovskite precursor solution preparation method.

[0080] The perovskite layer is a key component of perovskite solar cells, possessing excellent light absorption characteristics and photoelectric conversion efficiency, capable of converting incident photons into charge carriers. The perovskite precursor solution provided in this application is obtained using the aforementioned method for preparing the perovskite precursor solution, and the perovskite layer is prepared on a self-assembled monolayer using this perovskite precursor solution. For detailed explanations of related content, please refer to the section on the preparation method of the perovskite precursor solution above, which will not be repeated here.

[0081] In some embodiments, a perovskite precursor solution is spin-coated onto the surface of a self-assembled monolayer to form a perovskite liquid film on the surface of the self-assembled monolayer; an antisolvent is dropped onto the surface of the perovskite liquid film and annealed to allow the perovskite liquid film to crystallize and form a perovskite layer.

[0082] The antisolvent can be a solvent for purifying the solute, such as diethyl ether.

[0083] Since the perovskite precursor solution provided in this application contains diamine hydrobromide, and diamine hydrobromide can be used as a passivating agent, the cations in diamine hydrobromide can fill the defects of the A-site cations, and the bromide ions can fill the defects of the X-site anions. Therefore, a perovskite layer can be prepared using a perovskite precursor solution containing diamine hydrobromide, thereby eliminating the defects of the perovskite solar cell and improving the photoelectric performance, efficiency, and stability of the perovskite solar cell.

[0084] For example, 100 μL of perovskite precursor solution can be uniformly dropped onto the surface of a self-assembled monolayer to form a perovskite liquid film. Specifically, the mixture can be spin-coated at 1000 rpm for 10 s, then at 5000 rpm for 40 s to form the perovskite liquid film. Five seconds before the spin-coating is finished, 400 μL of diethyl ether is slowly dropped onto the surface of the perovskite liquid film. After this process, the ITO glass substrate is transferred to a hot stage and annealed at 110°C for 30 minutes to allow the perovskite liquid film to crystallize and form a perovskite layer.

[0085] In some embodiments, after preparing a perovskite layer on the self-assembled monolayer using a perovskite precursor solution, a phenylethyl ammonium bromide solution is spin-coated onto the surface of the perovskite layer and then annealed to obtain a passivated perovskite layer.

[0086] For example, after the ITO glass substrate with the perovskite layer formed is cooled to room temperature, 80 μL of phenylethyl ammonium bromide (PEABr) solution (1 mg / mL PEABr dissolved in isopropanol) can be spin-coated to the surface of the crystallized perovskite film at 4000 rpm for 30 s to passivate the defects on the surface of the perovskite film. Then, it is transferred to a hot stage and annealed at 100°C for 10 minutes to obtain the passivated perovskite layer.

[0087] Step S205: An electron transport layer is prepared on the perovskite layer to obtain the prefabricated device.

[0088] The electron transport layer is located on the perovskite layer. It has good electron conduction performance and band matching characteristics, which helps to improve electron collection efficiency and transport speed.

[0089] For example, 1 ml of chlorobenzene and 1 ml of isopropanol were added to 20 mg of PCBM (fullerene derivative) and 0.5 mg of BCP (organophosphorus compound), respectively, and the mixture was stirred at room temperature for 12 hours. The solution was then filtered through a nylon membrane (0.45 μm pore size). 80 μl of PCBM solution was dropped onto the surface of the perovskite layer and spin-coated at 2000 rpm for 30 seconds. Then, 100 μl of BCP solution was added and spin-coated at 4000 rpm for 30 seconds. After the solvent evaporated, an electron transport layer was formed on the perovskite layer.

[0090] Step S206: Fabricate a metal electrode on the prefabricated device to obtain a perovskite solar cell.

[0091] In a perovskite solar cell, metal electrodes are typically located at the top and bottom. Common metals used for these electrodes include gold (Au), silver (Ag), aluminum (Al), or copper (Cu). The primary function of the metal electrodes is to collect electrons and holes and guide them to the external circuitry. Metal electrodes possess good electrical conductivity and light reflection characteristics to reduce energy loss and increase current output.

[0092] In some embodiments, the metal electrode includes a gold electrode and a silver electrode, as the gold electrode has excellent conductivity.

[0093] For example, the prefabricated device is transferred into a vacuum coating machine, and the vacuum level inside the vacuum coating machine is controlled to reach 1x10⁻⁶. -5 After Pa, silver electrodes were deposited by vapor deposition at a rate of 0.1-1.01, with a thickness of 100 nm, to obtain perovskite solar cells.

[0094] For example, the thickness of the metal electrode can be 100 nm, and the effective area of ​​the perovskite solar cell can be 0.06 cm². 2 .

[0095] The rational design and optimization of the structures of these components of the perovskite solar cell can effectively eliminate the defects present in existing perovskite solar cells and improve the photoelectric performance, efficiency and stability of perovskite solar cells.

[0096] This application also provides a perovskite solar cell, which is prepared using any of the above-described methods for preparing perovskite solar cells.

[0097] Perovskite solar cells are high-efficiency photoelectric conversion devices based on perovskite materials. Their structure mainly consists of five key parts: a transparent conductive glass substrate, a hole transport layer (HTL), a perovskite layer, an electron transport layer (ETL), and a metal electrode. The ETL must have good contact with the perovskite layer to reduce the potential barrier for electron transport and prevent hole transport to the cathode while completing electron transport. Currently, mesoporous layer structures are commonly used, such as TiO2 or Al2O3, which also provide structural support. The HTL needs a good heterojunction interface with the perovskite layer to reduce the potential barrier for hole transport and prevent electron movement to the anode while completing hole transport. The hole transport layer can be organic (such as Spiro-OMeTAD small molecule materials, triphenylamine, etc.) or inorganic compounds (such as copper iodide, nickel oxide, etc.). Transparent conductive glass substrates are typically made of commercially available ITO (indium tin oxide) or FTO (fluorine-doped tin oxide) conductive glass, which boasts a transmittance of 80-90% in the visible light band, strong conductivity, and a suitable work function. The perovskite layer, usually an organometallic halide, is used to absorb light and generate electron-hole pairs. The perovskite solar cell provided in this application effectively eliminates the defects present in existing perovskite solar cells, improving their photoelectric performance, efficiency, and stability.

[0098] The following specific embodiment will be used to illustrate in detail the preparation method of the perovskite precursor solution, the preparation method of the perovskite solar cell, and the perovskite solar cell of this application.

[0099] I. Preparation process of perovskite precursor solution:

[0100] Example 1:

[0101] 1. The component was determined to be Cs. 0.05 FA 0.85 MA 0.1 Pb I3. Dissolve 760.7 mg of Pb I2, 219.3 mg of FAI, 23.8 mg of MAI, and 19.5 mg of Cs I in 1 mL of a mixed solvent of DMF and DMSO (the ratio of DMF to DMSO can be 4:1). Stir at room temperature for 12 hours to dissolve the above substances in the mixed solvent of DMF and DMSO to obtain the first solution.

[0102] 2. Add 12.5 mol% MAC l to the first solution and stir at room temperature for 2 hours to obtain the second solution. Then add 0.08 mol% ODADBr to the second solution and stir until completely dissolved.

[0103] 3. The solution is filtered using a nylon filter membrane (pore size 0.45μm). After aging the filtered solution at room temperature for 4 hours, the perovskite precursor solution can be obtained.

[0104] Example 2:

[0105] 1. The component was determined to be Cs. 0.05 FA 0.85 MA 0.1 Pb I3. Dissolve 760.7 mg of Pb I2, 219.3 mg of FAI, 23.8 mg of MAI, and 19.5 mg of Cs I in 1 mL of a mixed solvent of DMF and DMSO (the ratio of DMF to DMSO can be 4:1). Stir at room temperature for 12 hours to dissolve the above substances in the mixed solvent of DMF and DMSO to obtain the first solution.

[0106] 2. Add 12.5 mol% MACl to the first solution and stir at room temperature for 2 hours to obtain the second solution. Then add 0.08 mol% HDADBr to the second solution and stir until completely dissolved.

[0107] 3. The solution is filtered using a nylon filter membrane (pore size 0.45μm). After aging the filtered solution at room temperature for 4 hours, the perovskite precursor solution can be obtained.

[0108] Control group:

[0109] 1. The component was determined to be Cs. 0.05 FA 0.85 MA 0.1 PbI3. Dissolve 760.7 mg of PbI2, 219.3 mg of FAI, 23.8 mg of MAI, and 19.5 mg of CsI in 1 ml of a mixed solvent of DMF and DMSO (the ratio of DMF to DMSO can be 4:1). Stir at room temperature for 12 hours to dissolve the above substances in the mixed solvent of DMF and DMSO to obtain the first solution.

[0110] 2. Add 12.5 mol% MACl to the first solution and stir at room temperature for 2 hours to obtain the second solution.

[0111] 3. The second solution is filtered using a nylon filter membrane (pore size 0.45μm). After aging the filtered second solution at room temperature for 4 hours, the perovskite precursor solution can be obtained.

[0112] In the control group, the perovskite precursor solution did not contain ODADBr or HDADBr, and the other steps were the same.

[0113] II. Fabrication process of perovskite solar cells:

[0114] 1. Substrate Cleaning: Select an ITO (specification: 20*16*0.7mm) transparent conductive glass substrate. Scrub the substrate with soapy water and rinse with deionized water. Then, ultrasonically clean the substrate sequentially in deionized water and ethanol for 30 minutes each. Place the cleaned substrate in a vacuum drying oven and bake at 80℃ for 12 hours. Finally, perform plasma treatment on the substrate surface for 3 minutes to enhance its wettability.

[0115] 2. Hole Transport Layer (HTL) Deposition: Add 1 ml of deionized water to 15 mg of nickel oxide and sonicate for 10 min to form a nickel oxide dispersion. Then filter the nickel oxide dispersion with a nylon filter membrane (pore size 0.45 μm) to obtain a nickel oxide dispersion with good dispersibility. Drop 80 μL of nickel oxide dispersion onto an ITO glass substrate cooled to room temperature, spin coat at 2000 rpm for 30 s, and transfer to a hot stage at 150 °C for annealing for 20 min to form a nickel oxide thin film, i.e., a hole transport layer, on the surface of the ITO glass substrate.

[0116] 3. Self-assembled monolayer (SAMs) deposition: Add 1 ml of anhydrous ethanol to 0.5 mg Me-4PACz, stir at room temperature for 12 hours, and then filter the solution through a nylon membrane (0.45 μm pore size). Drop 100 μl of the filtered solution onto the surface of the hole transport layer, spin-coat at 4000 rpm for 30 s, and then transfer it to a hot plate at 100 °C for annealing for 10 min to allow the self-assembled monomolecules to anchor on the surface of the hole transport layer.

[0117] 4. Perovskite Layer Deposition: Prepare 100 μL of the perovskite precursor solution obtained in Examples 1, 2, and the control group. Uniformly drop 100 μL of the above perovskite precursor solution onto the surface of the self-assembled monolayer to form a perovskite liquid film. Specifically, spin-coat at 1000 rpm for 10 s, then spin-coat at 5000 rpm for 40 s to form the perovskite liquid film. Five seconds before the end of spin-coating, slowly drop 400 μL of diethyl ether onto the surface of the perovskite liquid film. After this process, transfer the ITO glass substrate to a hot stage and anneal at 110°C for 30 minutes to allow the perovskite liquid film to crystallize.

[0118] 5. After the ITO glass substrate with the formed perovskite layer has cooled to room temperature, 80 μL of phenylethyl ammonium bromide (PEABr) solution (1 mg / mL PEABr dissolved in isopropanol) can be spin-coated to the surface of the crystallized perovskite film at 4000 rpm for 30 s to passivate the defects on the surface of the perovskite film. Then, it is transferred to a hot stage and annealed at 100°C for 10 minutes to obtain the passivated perovskite layer.

[0119] 6. Electron Transport Layer (ETL) Deposition: 1 ml of chlorobenzene and 1 ml of isopropanol were added to 20 mg of PCBM (fullerene derivative) and 0.5 mg of BCP (organophosphorus compound), respectively. The mixture was stirred at room temperature for 12 hours, and then filtered through a nylon membrane (0.45 μm pore size). 80 μl of PCBM solution was dropped onto the surface of the perovskite layer and spin-coated at 2000 rpm for 30 seconds. Then, 100 μl of BCP solution was added and spin-coated at 4000 rpm for 30 seconds. After the solvent evaporated, an electron transport layer was formed on the perovskite layer.

[0120] 7. Silver electrode evaporation: Transfer the pre-fabricated device into a vacuum coating machine, and control the vacuum level inside the machine to reach 1x10⁻⁶. -5 After Pa, silver electrodes were deposited by vapor deposition at a rate of 0.1-1.01, with a thickness of 100 nm, to obtain perovskite solar cells.

[0121] Therefore, it can be seen that three types of perovskite solar cells can be prepared through the above-described perovskite solar cell preparation process. The difference between the three types of perovskite solar cells lies in the different perovskite precursor solutions, namely: the perovskite layer prepared by the perovskite precursor solution provided in Example 1, the perovskite layer prepared by the perovskite precursor solution provided in Example 2, and the perovskite layer prepared by the perovskite precursor solution provided in the control group.

[0122] like Figure 5 As shown, Figure 5 This document provides a schematic diagram of a pure hole device structure and the calculation of defect state density, as provided in an embodiment of this application. Perovskite layers were prepared using perovskite precursor solutions obtained in Examples 1, 2, and the control group, respectively. Pure hole devices were then fabricated using these perovskite layers. The structure of the pure hole device includes Ag (silver) and MoO. x (Molybdenum oxide, hole transport layer), Perovskite, Me-4PACz (SAMs), NiO x (Nickel oxide, hole transport layer) and ITO (indium tin oxide). The hole defect state density was calculated to be 2.97 * 10⁻⁶ for the pure hole device fabricated in the control group. 15 cm-3 The defect state density of the pure hole device prepared in Example 1 is 2.35*10. 15 cm -3 The defect state density of the pure hole device prepared in Example 2 is 1.84*10. 15 cm -3 It can be seen that the defect state density of the pure hole devices prepared in Examples 1 and 2 is much smaller than that of the pure hole devices prepared in the control group, thus indicating that the perovskite solar cells provided in this application can effectively eliminate the crystal defects present therein.

[0123] like Figure 6 As shown, Figure 6 This diagram illustrates the defect state density of a pure electronic device provided in this application embodiment. Perovskite layers were prepared using perovskite precursor solutions obtained in Examples 1, 2, and the control group, respectively. Pure electronic devices were then fabricated using these perovskite layers. The structure of the pure electronic devices includes Ag (silver), PCBM (fullerene derivative, electron transport layer), Perovskite, Me-4PACz (SAMs), SnO2 (tin oxide, electron transport layer), and ITO (indium tin oxide). The defect state density of the pure electronic device prepared in the control group was calculated to be 8.96 * 10⁻⁶. 14 cm -3 The defect state density of the pure electronic device prepared in Example 1 is 7.84 * 10^6. 14 cm -3 The defect state density of the pure electronic device obtained in Example 2 is 6.72*10. 14 cm -3 It can be seen that the defect state density of the pure electronic devices prepared in Examples 1 and 2 is much smaller than that of the pure electronic devices prepared in the control group, thus indicating that the perovskite solar cells provided in this application can effectively eliminate the crystal defects present therein.

[0124] As shown in Figure 7(a), after X-ray irradiation, the ratio of the intensity of the (001) peak to the (112) peak scattered by the perovskite film increased from 0.796 (control group) to 1.639 (Example 1) and 2.088 (Example 2). This indicates that the perovskite films prepared using the perovskite precursor solutions provided in Examples 1 and 2 have better crystal orientation. Furthermore, the perovskite film prepared using the perovskite precursor solution provided in the control group showed an impurity peak (marked with a pentagram; this impurity peak was identified as PbI2 after testing).

[0125] As shown in Figure 7(b), which is the half-peak width of peak (001), the narrowing of the half-peak width in Examples 1 and 2 indicates an increase in the perovskite grain size and better crystal quality, consistent with the results of the SEM images below.

[0126] As shown in Figures 8(a), 8(b), 8(c), and 8(d), the SEM image in Figure 8(a) reveals that the perovskite film prepared using the perovskite precursor solution provided in the control group contains numerous lead iodide impurities at the grain boundaries, and the perovskite grains are uneven in size with a small average grain size. The SEM images in Figures 8(b) and 8(c) show that the perovskite films prepared using the perovskite precursor solutions provided in Examples 1 and 2 exhibit reduced impurities at the grain boundaries, and the grains are more uniform in size with a larger average grain size. A statistical chart of their grain sizes is shown in Figure 8(d).

[0127] As shown in Figures 9(a), 9(b), and 9(c), the AFM images show that the average roughness of the perovskite layer surface decreased from 15.9 nm (control group) to 15.1 nm (Example 1) and 14.1 nm (Example 2).

[0128] like Figure 10 As shown, Figure 10 This is a schematic diagram of the photoelectric performance JV curve and Nyquist plot of a perovskite solar cell provided in an embodiment of this application.

[0129] Depend on Figure 10 The top left image shows the open-circuit voltage versus light intensity (V). OC As shown in the light intensity graph, the open-circuit voltage of the perovskite solar cell increases linearly with increasing light intensity. However, under the same light intensity, the open-circuit voltage of the perovskite solar cells in Examples 1 and 2 is greater than that of the control group. The slope of the fitted line of the perovskite solar cell in the control group is 1.78 kT / q, the slope of the fitted line of the perovskite solar cell in Example 1 is 1.63 kT / q, and the slope of the fitted line of the perovskite solar cell in Example 2 is 1.58 kT / q.

[0130] Figure 10 The upper right figure shows the leakage current of the device, which illustrates that the leakage current of the perovskite solar cells in Examples 1 and 2 is less than that of the perovskite solar cells in the control group.

[0131] Figure 10 The lower left figure shows the equivalent circuit diagram of the electrochemical impedance spectroscopy and fitting curve, also known as the Nyquist plot. A perovskite solar cell can be equivalently represented by the circuit shown in the figure. Theoretically, the series resistance R of an ideal photovoltaic device...s The smaller the parallel resistance R, the better. rec A higher R value results in a lower overall resistance during operation, which is more conducive to charge transport and extraction. As shown in the lower left figure, the R values ​​of the perovskite solar cells in Examples 1 and 2 are... s Compared to the control group of perovskite solar cells, R s Small, R of perovskite solar cells in Examples 1 and 2 rec Compared to the control group of perovskite solar cells, R rec The requirement for a large charge size indicates that the perovskite solar cell provided in this application embodiment can help enhance charge extraction capability, making charge recombination difficult.

[0132] Figure 10 The lower right figure shows the Mott-Schottky curves, which reveal the built-in electric field strength of the perovskite solar cell, at 0.90V (control group), 0.96V (Example 1), and 1.01V (Example 2). This demonstrates that the increase in the open-circuit voltage of the perovskite solar cell provided in this application embodiment is related to the increase in the built-in electric field strength.

[0133] The above comparison figures all illustrate that the perovskite solar cells provided in the embodiments of this application, compared with the perovskite solar cells provided by the prior art, can not only effectively eliminate defects, but also have superior optical performance.

[0134] As shown in Figure 11(a), the horizontal axis represents voltage (in V) and the vertical axis represents current density (in mA / cm²). 2 The open-circuit voltage V of the control group perovskite solar cells OC Short-circuit current density J SC The fill factor (FF) and photoelectric conversion efficiency (PCE) are 1.164V and 24.39mA / cm, respectively. 2 80.24%, 22.78%, the open-circuit voltage V of the perovskite solar cell in Example 1 OC Short-circuit current density J SC The fill factor (FF) and photoelectric conversion efficiency (PCE) are 1.179V and 25.05mA / cm, respectively. 2 82.87%, 24.40%, the open-circuit voltage V of the perovskite solar cell in Example 2 OC Short-circuit current density J SC The fill factor (FF) and photoelectric conversion efficiency (PCE) are 1.187V and 25.43mA / cm, respectively. 2 83.04% and 25.07%.

[0135] As shown in Figure 11(b), the hysteresis of the perovskite solar cell provided by the control group was 3.33%, the hysteresis of the perovskite solar cell provided by Example 1 was 1.80%, and the hysteresis of the perovskite solar cell provided by Example 2 was 2.60%.

[0136] As shown in Figure 11(c), the horizontal axis represents time (in seconds), and the vertical axis represents current density and PCE. The device continuously outputs power for 600 seconds at its maximum power point. The current density and PCE of the perovskite solar cell remain relatively stable. The operating voltage V of the control group perovskite solar cell... m Current density J m The voltage and PCE are 0.98V and 22.60mA / cm, respectively. 2 22.15%, the operating voltage V of the perovskite solar cell in Example 1 m Current density J m The voltage and PCE are 1.00V and 24.08mA / cm, respectively. 2 24.08%, the operating voltage V of the perovskite solar cell in Example 2 m Current density J m The voltage and PCE are 1.02V and 24.40mA / cm, respectively. 2 24.88%.

[0137] The above comparison figures illustrate that the perovskite solar cells provided in this application not only effectively eliminate defects but also have higher efficiency compared to perovskite solar cells provided by the prior art.

[0138] As shown in Figure 12(a), the horizontal axis represents time (in hours), and the vertical axis represents the homogenized PCE. Within the range of 0-3600 hours, the homogenized PCE of the perovskite solar cells gradually decreases. At any point within this range, the homogenized PCE of the perovskite solar cells provided in Examples 1 and 2 is greater than that of the perovskite solar cells provided in the control group. Unencapsulated devices were stored in a nitrogen atmosphere at 25°C for approximately 3600 hours. The efficiency of the perovskite solar cells provided in the control group was less than 80% of the initial efficiency, while the efficiency of the perovskite solar cells provided in Example 1 remained at 94% of the initial efficiency, and the efficiency of the perovskite solar cells provided in Example 2 remained at 96% of the initial efficiency.

[0139] As shown in Figure 12(b), the thermal stability of the perovskite solar cells provided by the control group, Example 1, and Example 2 was tested. The horizontal axis represents time (in hours), and the vertical axis represents the homogenized PCE. Within the range of 0-1800 hours, the homogenized PCE of the perovskite solar cells gradually decreased. At any time point within the 0-1800 hour range, the homogenized PCE of the perovskite solar cells provided by Examples 1 and 2 was greater than that of the perovskite solar cell provided by the control group. Under nitrogen atmosphere and at a temperature of 65°C, the unencapsulated devices showed that the perovskite solar cell provided by the control group maintained more than 80% of its initial efficiency for 800 hours, while the perovskite solar cell provided by Example 1 maintained its efficiency for 1500 hours, and the perovskite solar cell provided by Example 2 maintained its efficiency for 1800 hours.

[0140] The above comparison figures all illustrate that the perovskite solar cells provided in the embodiments of this application, compared with the perovskite solar cells provided by the prior art, can not only effectively eliminate defects, but also have higher stability.

[0141] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a perovskite precursor solution, characterized in that, The perovskite precursor solution is used to prepare the perovskite layer of a perovskite solar cell, and the preparation method includes: Based on the composition of perovskite materials Cs 0.05 FA 0.85 MA 0.1 PbI3 was used to determine a number of substances used in the synthesis of the perovskite material and their contents, and the number of substances were dissolved to obtain a first solution. The crystallization aid is dissolved in the first solution to obtain the second solution; Diamine hydrobromide was dissolved in the second solution to obtain a perovskite precursor solution; The carbon chain length of the diamine hydrobromide is 6-8 carbon atoms.

2. The preparation method according to claim 1, characterized in that, The substances mentioned include PbI2, FAI, MAI, and CsI.

3. The preparation method according to claim 1, characterized in that, The process of dissolving the plurality of substances to obtain a first solution includes: The substances are dissolved in a mixed solvent of DMF and DMSO to obtain a first solution.

4. The preparation method according to claim 1, characterized in that, The molar fraction percentage of the diamine hydrobromide is 0.04-0.12 mol.

5. The preparation method according to claim 1, characterized in that, The diamine hydrobromide includes 1,8-octanediamine hydrobromide and 1,6-hexanediamine hydrobromide.

6. A method for fabricating a perovskite solar cell, characterized in that, The preparation method includes: Provide transparent conductive glass substrates; A hole transport layer is prepared on the transparent conductive glass substrate; A self-contained monolayer was prepared on the hole transport layer. A perovskite layer is prepared on the self-assembled monolayer using a perovskite precursor solution, wherein the perovskite precursor solution is prepared using the method for preparing the perovskite precursor solution according to any one of claims 1-5. An electron transport layer is fabricated on the perovskite layer to obtain a pre-fabricated device. Metal electrodes are fabricated on the prefabricated device to obtain a perovskite solar cell.

7. The preparation method according to claim 6, characterized in that, The preparation of a perovskite layer on the self-assembled monolayer using a perovskite precursor solution includes: The perovskite precursor solution is spin-coated onto the surface of the self-assembled monolayer to form a perovskite liquid film on the surface of the self-assembled monolayer. The antisolvent is dropped onto the surface of the perovskite liquid film and then annealed to allow the perovskite liquid film to crystallize and form a perovskite layer.

8. The preparation method according to claim 6, characterized in that, After preparing the perovskite layer on the self-assembled monolayer using the perovskite precursor solution, the method further includes: A phenylethyl ammonium bromide solution was spin-coated onto the surface of the perovskite layer and then annealed to obtain a passivated perovskite layer.

9. A perovskite solar cell, characterized in that, The perovskite solar cell is prepared by using any one of the perovskite solar cell preparation methods according to claims 6 to 8.

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