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

Abstract

The application relates to the new energy technology field, in particular to a perovskite solar cell and a preparation method thereof, a laminated battery and a photovoltaic module. The perovskite solar cell comprises a transparent conductive electrode, a first charge transport layer, a perovskite absorption layer and a second charge transport layer which are sequentially laminated, the first charge transport layer or the second charge transport layer comprises a hole transport material, and the hole transport material comprises a compound of formula I. The compound of formula I is used as a novel hole transport material, has high hole mobility and energy levels matched with perovskite, can be applied to the perovskite solar cell without doping a dopant, exhibits excellent photoelectric conversion efficiency, and the photoelectric conversion efficiency can be kept stable for a long time. Formula I.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to perovskite solar cells and their preparation methods, tandem cells and photovoltaic modules. Background Technology

[0002] With the continued exploitation of non-renewable resources such as coal and oil, humanity is facing the imminent problem of energy depletion. Simultaneously, environmental pollution caused by mining has placed a heavy burden on the Earth's ecosystem. Faced with this situation, the exploration of new clean energy sources has become a crucial issue in line with current social development. Renewable energy has rapidly become a focus of attention, among which solar energy has outstanding advantages such as being environmentally friendly, pollution-free, and abundant. The invention of solar cells, which can achieve photoelectric conversion, has enabled the effective utilization of solar energy, giving us new hope in the face of energy shortages.

[0003] The hole transport layer is a key functional layer in perovskite solar cells, used to block electrons and enhance hole transport. Hole transport materials are mainly classified into inorganic, organic, and polymeric hole transport materials. Among them, organic hole transport materials have great application prospects due to the abundance of organic groups and the ability to obtain target molecules with desired structures through artificially designed synthetic routes. However, the use of organic hole transport materials can easily affect the long-term stability of the photoelectric conversion efficiency of perovskite cells, and the poor long-term stability of perovskite cells is a major bottleneck affecting their further commercialization. Summary of the Invention

[0004] Based on this, the first aspect of this application provides a perovskite solar cell, the technical solution of which is as follows:

[0005] A perovskite solar cell includes a transparent conductive electrode, a first charge transport layer, a perovskite absorber layer, and a second charge transport layer stacked sequentially. The first or second charge transport layer includes a hole transport material, which comprises a compound of formula I.

[0006] Formula I;

[0007] R1 is selected from H or F;

[0008] R2 is selected from C 5-7 alkyl.

[0009] The second aspect of this application provides a method for fabricating a perovskite solar cell, the technical solution of which is as follows:

[0010] A method for fabricating a perovskite solar cell includes the following steps: sequentially forming a first charge transport layer, a perovskite absorber layer, and a second charge transport layer on a transparent conductive electrode, wherein the first charge transport layer or the second charge transport layer includes a hole transport material, and the method for preparing the hole transport material includes the following steps:

[0011] The first coupling reaction between compound a and compound b produces compound c.

[0012] In the presence of an organolithium reagent, compound c undergoes a substitution reaction with an organotin halide compound to generate compound d.

[0013] The compound of formula d undergoes a second coupling reaction with the compound of formula e to generate the compound of formula I.

[0014] Formula a; Formula b; Formula c; Formula d; Formula e;

[0015] Formula I.

[0016] A third aspect of this application provides a stacked battery, the technical solution of which is as follows:

[0017] A tandem solar cell includes a top cell and a bottom cell stacked together, wherein the top cell includes at least one perovskite solar cell, which is prepared as described above or by the preparation method described above.

[0018] The fourth aspect of this application provides a photovoltaic module, the technical solution of which is as follows:

[0019] A photovoltaic module includes a perovskite solar cell as described above, or a perovskite solar cell prepared by the preparation method described above, or a tandem cell as described above.

[0020] Compared with traditional solutions, this application has the following advantages:

[0021] This application combines a triphenylamine-substituted thiopheneazine unit with a bisthiophene unit to design a compound of formula I, which contains a triphenylamine group. This improves the compound's thermal and morphological stability, giving it good charge transport properties and ionization potential. Furthermore, the triphenylamine group in this application is substituted with a methylthio group, and the sulfur atom interacts with the Pb in the perovskite. 2+ There are stronger interactions between them, which can effectively passivate uncoordinated Pb on the interface. 2+This reduces carrier recombination and enhances hole transport and extraction at the interface. Using the compound of formula I as a novel hole transport material, it exhibits high hole mobility and energy levels matching perovskite, allowing it to be applied in perovskite solar cells without doping. It demonstrates excellent photoelectric conversion efficiency, which remains stable over a long period, overcoming a major bottleneck for the further commercialization of perovskite solar cells.

[0022] Meanwhile, the hole transport material of this application is composed of lightweight, flexible, and environmentally friendly small organic molecules, suitable for a wide variety of organic solvents, exhibiting excellent solubility and film-forming properties, i.e., good solution processability. Furthermore, when using the hole transport material of this application to prepare inverted perovskite solar cells, a perovskite absorber layer is formed on the hole transport layer, which promotes the crystallization and growth of perovskite, resulting in a perovskite absorber layer with relatively uniform crystal size, large grain size, and tight packing, without obvious boundary defects. This is suitable for the preparation of large-area inverted perovskite solar cells. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application and to more completely understand this application and its beneficial effects, the drawings used in the description of 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.

[0024] Figure 1 A schematic diagram of a perovskite solar cell according to one embodiment;

[0025] Figure 2 The NMR spectrum of compound I-1;

[0026] Figure 3 The NMR spectrum of compound I-2;

[0027] Figure 4 This is a front-side SEM image of the perovskite absorber layer in Example 3;

[0028] Figure 5 This is a cross-sectional SEM image of the perovskite absorber layer in Example 3. Detailed Implementation

[0029] The present application will be further described in detail below with reference to specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0031] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0032] In this application, the terms "optionally," "optionally," and "optional" refer to options that are optional, meaning they can be selected from either "with" or "without." If multiple "optional" options appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" option is independent.

[0033] In this application, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth," etc., serve only a non-exhaustive enumeration purpose and should be understood not to constitute a closed limitation on quantity.

[0034] In this application, numerical intervals (i.e. numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the above-mentioned numerical intervals are considered continuous, and include the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical range, as well as every value between the two numerical endpoints.

[0035] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0036] This application provides a perovskite solar cell in one embodiment, comprising a transparent conductive electrode, a first charge transport layer, a perovskite absorber layer, and a second charge transport layer stacked sequentially, wherein the first charge transport layer or the second charge transport layer comprises a hole transport material, and the hole transport material comprises a compound of formula I:

[0037] Formula I;

[0038] R1 is selected from H or F;

[0039] R2 is selected from C 5-7 alkyl.

[0040] Optionally, the hole transport material comprises at least one of the compounds of formula I-1 and formula I-2:

[0041] Formula I-1;

[0042] Formula I-2.

[0043] The small molecule organic compounds described in the above embodiments combine a triphenylamine-substituted thiophenezine unit with a bisthiophene unit to design compounds of formula I, wherein the presence of a triphenylamine group (TPA) is beneficial for improving the thermal and morphological stability of the compound, giving it good charge transport properties and ionization potential. Furthermore, in this application, the triphenylamine group is replaced by a methylthio group, and the sulfur atom interacts with the Pb in the perovskite. 2+ There are stronger interactions between them, which can effectively passivate uncoordinated Pb on the interface. 2+ This reduces carrier recombination and enhances hole transport and extraction at the interface. Using the compound of formula I as a novel hole transport material, it exhibits high hole mobility and energy levels matching perovskite, allowing it to be applied in perovskite solar cells without doping. It demonstrates excellent photoelectric conversion efficiency, which remains stable over a long period, overcoming a major bottleneck for the further commercialization of perovskite solar cells.

[0044] Meanwhile, the hole transport material of this application is composed of lightweight, flexible, and environmentally friendly small organic molecules, suitable for a wide variety of organic solvents, exhibiting excellent solubility and film-forming properties, i.e., good solution processability. Furthermore, when using the hole transport material of this application to fabricate inverted perovskite solar cells, a perovskite absorber layer is formed on the hole transport layer, which promotes the crystal growth of perovskite, resulting in a perovskite absorber layer with relatively uniform crystal size, large grain size, and tight packing, without obvious boundary defects. This is suitable for the fabrication of large-area inverted perovskite solar cells.

[0045] Optionally, R1 is F. The hole transport material comprises a compound of formula I-2. First, F has strong electronegativity, which greatly affects the energy levels of organic materials. Second, the atomic size of F is very small and does not affect its molecular packing. In this embodiment, introducing F into the hole transport material helps to improve the planarity of the material through non-covalent interactions (such as F…S, F…H, and F…π), thereby improving the charge mobility of the material. In addition, hole transport materials with F functional groups promote the thermal stability and hydrophobicity of the material, which can improve the stability of the device.

[0046] Optionally, the HOMO energy level of the hole transport material is -5.25eV to -5.3eV.

[0047] Optionally, the thermal decomposition temperature of the hole transport material is 310℃~335℃.

[0048] The above-mentioned conjugated organic small molecule compounds containing multiple groups have novel structures and can be applied to new undoped hole transport materials. They have good solubility, film-forming properties, high hole mobility, and energy levels that match perovskite. They are suitable for large-area inverted perovskite solar cells, with good photoelectric conversion efficiency, good performance, and good long-term stability.

[0049] In some embodiments, the first charge transport layer is a hole transport layer, the second charge transport layer is an electron transport layer, and the hole transport layer includes a hole transport material. In this case, the perovskite solar cell is an inverted perovskite solar cell.

[0050] Optionally, the perovskite solar cell further includes a metal electrode located on the second charge transport layer.

[0051] In one example of this implementation, see Figure 1 This is a schematic diagram of the structure of a perovskite solar cell 100. The perovskite solar cell includes a transparent conductive electrode 11, a hole transport layer 12, a perovskite absorber layer 13, an electron transport layer 14, and a metal electrode 15, stacked sequentially. The transparent conductive electrode 11 is ITO glass. The hole transport layer 12 includes the aforementioned hole transport material. The perovskite absorber layer is a quasi-two-dimensional perovskite. The electron transport layer includes PC61BM. The metal electrode includes at least one of chromium (Cr) and gold (Au).

[0052] A second aspect of this application provides a method for fabricating a perovskite solar cell. In one embodiment, the method includes the following steps: sequentially forming a first charge transport layer, a perovskite absorption layer, and a second charge transport layer on a transparent conductive electrode. The first charge transport layer or the second charge transport layer includes a hole transport material. The method for preparing the hole transport material includes the following steps:

[0053] S10. Compound a undergoes a first coupling reaction with compound b to produce compound c.

[0054] Formula a; Formula b; Formula c.

[0055] Optionally, the coupling reaction between compound a and compound b includes the following steps:

[0056] The first coupling reaction occurs when the compound of formula a, the compound of formula b, the first catalyst, the first base agent, and the first solvent are mixed.

[0057] Optionally, the molar ratio of compound a to compound b is 1:(1.1~2).

[0058] Optionally, the first catalyst comprises tetrakis(triphenylphosphine)palladium (Pd(PPh3)4). Optionally, the molar ratio of the compound of formula a to tetrakis(triphenylphosphine)palladium is 1:(0.05~1).

[0059] Optionally, the first alkali agent comprises potassium carbonate. Optionally, the molar ratio of the compound of formula a to potassium carbonate is 1:(5~10).

[0060] Optionally, the first solvent includes at least one of toluene, ethanol, and water. Optionally, the volume ratio of toluene, ethanol, and water is (1.5~2.5):(0.8~1.2):1.

[0061] Optionally, the temperature of the first coupling reaction is 80℃~90℃.

[0062] Optionally, the first coupling reaction takes 6 to 12 hours.

[0063] S20. In the presence of an organolithium reagent, compound c undergoes a substitution reaction with an organotin halide compound to generate compound d.

[0064] Formula c; Formula d.

[0065] Optionally, in the presence of an organolithium reagent, the compound of formula c undergoes a substitution reaction with an organotin halide compound, comprising the following steps:

[0066] A mixture of compound C and a second solvent is added, along with an organolithium reagent to lithiate the compound C. Then, the organotin halide compound is added, resulting in a substitution reaction.

[0067] Optionally, the organolithium reagent includes n-butyllithium. Optionally, the molar ratio of the compound of formula c to n-butyllithium is 1:(1.2~3).

[0068] Optionally, the organotin halide compound includes trimethyltin chloride. Optionally, the molar ratio of the compound of formula c to trimethyltin chloride is 1:(2.2~4).

[0069] Optionally, the second solvent comprises tetrahydrofuran.

[0070] Optionally, the reaction conditions for lithiation of the compound of formula c include: reacting at -80℃ to 40℃ for 0.5 to 2 hours. Optionally, the reaction conditions for lithiation of the compound of formula c include: reacting at -80℃ to -76℃ for 0.5 to 1.5 hours, followed by reacting at 10℃ to 40℃ for 20 minutes to 1 hour.

[0071] Optionally, the reaction conditions for the substitution reaction include: reacting at -80℃ to 40℃ for 0.5 to 2 hours. Optionally, the reaction conditions for the substitution reaction include: reacting at -80℃ to -76℃ for 10 to 20 minutes, followed by reacting at 10℃ to 40℃ for 0.5 to 1.5 hours.

[0072] S30, causes the compound of formula d to undergo a second coupling reaction with the compound of formula e, generating the compound of formula I.

[0073] Formula d; Formula e;

[0074] Formula I.

[0075] Optionally, the coupling reaction between the compound of formula d and the compound of formula e includes the following steps:

[0076] The second coupling reaction occurs when the compound of formula d, the compound of formula e, the third catalyst, and the third solvent are mixed.

[0077] Optionally, the molar ratio of compound d to compound e is 1:(2.2~3).

[0078] Optionally, the third catalyst comprises tetrakis(triphenylphosphine)palladium (Pd(PPh3)4). Optionally, the molar ratio of the compound of formula d to tetrakis(triphenylphosphine)palladium is 1:(0.05~0.1).

[0079] Optionally, the third solvent includes toluene.

[0080] Optionally, the temperature of the second coupling reaction is 110℃~120℃.

[0081] Optionally, the second coupling reaction takes 36 to 50 hours.

[0082] The above synthetic route involves few steps and uses inexpensive raw materials, which is beneficial for cost control.

[0083] Optionally, the first charge transport layer is a hole transport layer, comprising a hole transport material, and the method for forming the hole transport layer on the transparent conductive electrode is a solution method. Optionally, forming the hole transport layer on the transparent conductive electrode includes the following steps: mixing the hole transport material and a solvent to obtain a solution; coating the solution onto the transparent conductive electrode; and annealing. Optionally, each 1 mL of solution contains 3 mg to 15 mg of hole transport material. Optionally, the solvent can be chlorobenzene. The aforementioned hole transport materials all have good solubility in chlorobenzene. Optionally, the annealing temperature is 90℃ to 110℃. Optionally, the annealing time is 8 min to 12 min.

[0084] After forming the hole transport layer, a perovskite absorber layer is formed on the hole transport layer. The perovskite absorber layer is a quasi-two-dimensional perovskite. Optionally, the method for forming the perovskite absorber layer on the hole transport layer is a solution method. Optionally, forming the perovskite absorber layer on the hole transport layer includes the following steps: mixing a perovskite material and a solvent to obtain a solution; coating the solution onto the hole transport layer; and annealing. Optionally, the perovskite material is selected from at least one of 3-fluorobenzylammonium iodide (3FBAI), 3-bromobenzylammonium iodide, 3-chlorobenzylammonium iodide, methylammonium chloride, and lead iodide. Optionally, the solvent can be at least one of DMF and DMSO.

[0085] Optionally, the second charge transport layer is an electron transport layer, and the method for forming the electron transport layer on the perovskite absorber layer is a solution method. Optionally, forming the electron transport layer on the perovskite absorber layer includes the following steps: mixing an electron transport material and a solvent to obtain a solution; coating the solution onto the perovskite absorber layer; and annealing. Optionally, the electron transport material includes PC61BM.

[0086] Optionally, the method for fabricating a perovskite solar cell further includes the step of forming a metal electrode on a second charge transport layer. Optionally, the method for forming the metal electrode on the second charge transport layer is vacuum evaporation. Optionally, the metal electrode includes at least one of chromium (Cr) and gold (Au).

[0087] A third aspect of this application provides a tandem solar cell. In one embodiment, the tandem solar cell includes a top cell and a bottom cell stacked together. The top cell includes at least one perovskite solar cell, which is prepared as described above or by the preparation method described above.

[0088] The fourth aspect of this application provides a photovoltaic module. In one embodiment, the photovoltaic module includes a perovskite solar cell as described above, or a perovskite solar cell prepared by the preparation method described above, or a tandem cell as described above.

[0089] The following detailed description is provided in conjunction with specific embodiments. Unless otherwise specified, all raw materials and instruments used in the following embodiments are commercially available. Unless otherwise specified, all processes involved are conventionally selected by those skilled in the art.

[0090] Example 1 Preparation of compound I-1

[0091]

[0092] The specific synthetic steps of compound 1-c were as follows: Compound 1-a (0.37 g, 1 mmol), compound 1-b (7.0 g, 1.5 mmol), tetrakis(triphenylphosphine)palladium (114 mg, 0.1 mmol), and potassium carbonate (1.4 g, 10 mmol) were weighed and added to a 50 mL double-necked flask. The solvent was toluene, ethanol, and water (volume ratio 2:1:1). The reaction was carried out at 85 °C for 6 hours. After cooling to room temperature, the mixture was extracted with saturated sodium chloride solution and dichloromethane. The organic phase was dried over anhydrous magnesium sulfate, filtered, and distilled under reduced pressure. Finally, the mixture was purified by column chromatography (PE:DCM = 6:1) to obtain 0.95 g of compound 1-c, with a yield of 67%.

[0093] The specific synthetic steps of compound 1-d were as follows: Compound 1-c (1.9 g, 3 mmol) and 30 mL of anhydrous tetrahydrofuran were weighed and added to a 100 mL double-necked flask. The mixture was pumped three times using a double-row tube and placed at -78 °C. 2.65 mL of n-butyllithium (6.62 mmol) was slowly added to a constant pressure burette and then very slowly added dropwise to the reaction system. The reaction was carried out at low temperature (-78 °C) for 30 minutes, followed by a reaction at room temperature for 40 minutes. The mixture was then placed at -78 °C again, and trimethyltin chloride (1 M / THF, 5 mL, 5 mmol) was added. The mixture was stirred at low temperature (-78 °C) for 10 minutes, followed by a reaction at room temperature for 1 hour. The reaction was terminated by adding 100 mL of deionized water. The mixture was extracted three times with diethyl ether, and the organic phases were combined. The crude product was finally purified by column chromatography (PE:DCM = 10:1) to obtain compound 1-d (1.1 g, yield 52%).

[0094] The specific synthetic steps of compound I-1 are as follows: Under nitrogen protection, compound 1-d (0.33 g, 1 mmol), compound 1-e (2.3 g, 3 mmol), Pd(PPh3)4 (57 mg, 0.05 mmol), and 30 mL of toluene were sequentially added to a 50 mL dry double-necked flask. The mixture was subjected to three double-row tube evacuations and stirred at 110 °C in the dark for 48 hours. After cooling to room temperature, the crude product was purified by rotary evaporation to remove excess mixed solvent. Finally, the crude product was purified by column chromatography (PE:DCM = 10:1) to obtain compound I-1 (0.62 g), with a yield of 46%. Its NMR spectrum is shown below. Figure 2 .

[0095] Example 2 Preparation of compound I-2

[0096]

[0097] The specific synthesis steps of compound 1-c are as follows: refer to Example 1.

[0098] The specific synthesis steps of the 1-d compound are as follows: refer to Example 1.

[0099] The specific synthetic steps of compound I-2 are as follows: Under nitrogen protection, compound 1-d (0.36 g, 1 mmol), compound 2-e (2.3 g, 3 mmol), Pd(PPh3)4 (57 mg, 0.05 mmol), and 30 mL of toluene were sequentially added to a 50 mL dry double-necked flask. The mixture was subjected to three separate extractions using a double-row tube, and the mixture was stirred at 110 °C in the dark for 48 hours. After cooling to room temperature, the crude product was purified by rotary evaporation to remove excess mixed solvent. Finally, the crude product was purified by column chromatography (PE:DCM = 10:1) to obtain compound I-2 (0.7 g), with a yield of 49%. Its NMR spectrum is shown below. Figure 3 .

[0100] Example 3

[0101] Perovskite solar cells were fabricated using the compound of formula I-1 prepared in Example 1 and the compound of formula I-2 prepared in Example 2 as hole transport materials, respectively, following the steps below:

[0102] (1) Cleaning: The ITO glass slide was ultrasonically cleaned with deionized water, acetone and ethanol for 15 minutes in sequence. Then, the residual solvent on the surface of the ITO glass slide was dried with an N2 gas gun. After that, oxygen plasma treatment was performed for 15 minutes. Then, the ITO glass slide was transferred to a nitrogen glove box.

[0103] (2) Preparation of hole transport layer: Weigh 10 mg of compound I-1 or compound I-2 and dissolve it completely in 1 mL of chlorobenzene solution. Take an appropriate amount of solution and drop it evenly onto the ITO glass substrate. Spin coat at 5000 rpm for 20 seconds, and then anneal at 100℃ for 10 minutes.

[0104] (3) Preparation of the perovskite absorber layer: The ITO / hole transport layer substrate obtained above was cooled to room temperature, preheated at 130°C for 5 minutes, and 50 μL of perovskite solution was spread evenly on the ITO / hole transport layer substrate. It was then spin-coated at 5000 rpm for 20 seconds and annealed at 100°C for 10 minutes to prepare the perovskite absorber layer. The perovskite solution was prepared by mixing 3-fluorobenzylammonium iodide (3FBAI), methylammonium chloride (MACI), and lead iodide (PbI2) in a mixed solvent of DMF and DMSO at a mass ratio of 2.2:3.5:4 (the volume ratio of DMF to DMSO was 4:1).

[0105] Figure 4 This is a front-view SEM image of the perovskite absorber layer prepared on a hole transport layer using the compound of formula I-2 as the hole transport material. Figure 5 This is a cross-sectional SEM image of a perovskite absorber layer fabricated on a hole transport layer prepared using the compound of formula I-2 as the hole transport material. Figure 4 and Figure 5 It can be seen that the perovskite thin film grown based on the hole transport layer has relatively uniform crystal size and large grain size, and the grains are closely packed with no obvious boundary defects. This illustrates that the compound of formula I-2, as a hole transport material, can promote the crystallization and growth of perovskite thin films during the fabrication of perovskite solar cells. It can also effectively and completely cover the hole transport layer, suppressing severe charge recombination defects caused by direct contact between the electron transport layer and the hole transport layer, thus contributing to the improvement of photovoltaic efficiency in perovskite solar cells.

[0106] (4) Preparation of electron transport layer: Cool the ITO / hole transport layer / perovskite absorber layer substrate obtained above to room temperature, prepare PC61BM into a 15 mg / mL solution, then take 40 μL of PC61BM solution to cover the ITO / hole transport layer / perovskite absorber layer substrate, spin coat at 1000 rpm for 30~50 seconds, and anneal at 90℃ for 10 minutes.

[0107] (5) Electrode preparation: The above-mentioned substrate is placed in a vacuum evaporation chamber, and Cr (6nm) and Au (80nm) are deposited on the PC61BM layer respectively to obtain the desired inverse quasi-two-dimensional perovskite solar cell.

[0108] Test Project

[0109] Project 1: Thermogravimetric analysis (TGA) was used to characterize compounds I-1 and I-2. N2 was selected as the protective gas, and the purge flow rate was set to 20 cm⁻¹. 3 The initial temperature was set at 25℃, and the heating rate was 10℃ / min. Analysis of the measured curves yielded the thermal decomposition temperature (Td, 5% weight loss) of the target product, and the results are recorded in Table 1.

[0110] Table 1

[0111]

[0112] Project 2: Testing the HOMO levels of compounds I-1 and I-2. The method was as follows: 5 mg of compound I-1 or compound I-2 was dissolved in a 0.1 M solution of tetrabutylammonium hexafluorophosphate (Bu4NPF6) in dichloromethane. Ferrocene was used as an external standard for calibration. Cyclic voltammetry curves were obtained on an electrochemical workstation at a purge rate of 0.01 V / s. The redox potentials of the curves were analyzed, and the HOMO levels of the compounds were calculated according to the formula. The results are recorded in Table 2.

[0113] Table 2

[0114]

[0115] Project 3: Testing the photoelectric conversion efficiency of perovskite solar cells containing compounds I-1 and I-2 from Example 3. The method was as follows: 25°C, one atmosphere, under standard simulated sunlight (AM 1.5G, 100 milliwatts per square centimeter (mW / cm²)). 2 Under irradiation, the battery performance was tested to obtain the IV curve (volt-ampere characteristic curve). Based on the IV curve and the data fed back by the testing equipment (four-channel digital source meter, Keithley 2450), the short-circuit current density Jsc (unit: milliampere / cm²) can be obtained. 2 The open-circuit voltage Voc (in volts (V)) is calculated using the formula FF = Jsc × Voc / (Jmpp × Vmpp), and the results are shown in Table 3. The fill factor FF of the battery can be calculated using the formula PCE = Jsc × Voc × FF / Pw, and the results are shown in Table 3. Pw represents the input power in milliwatts (mW), and the results are shown in Table 3.

[0116] Project 4: Testing the stability of the perovskite solar cells containing compounds I-1 and I-2 from Example 3. The method was as follows: After storing the encapsulated perovskite solar cells at 25°C and 30% relative humidity for 1000 hours, their photoelectric conversion efficiency was tested according to Project 3. The stability results are shown in Table 3.

[0117] Table 3

[0118]

[0119] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0120] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A perovskite solar cell, characterized in that, The structure comprises a transparent conductive electrode, a first charge transport layer, a perovskite absorber layer, and a second charge transport layer stacked sequentially. The first or second charge transport layer includes a hole transport material, which includes a compound of formula I. Formula I; R1 is selected from H or F; R2 is selected from C 5-7 alkyl.

2. The perovskite solar cell according to claim 1, characterized in that, The hole transport material includes at least one of the compounds of formula I-1 and formula I-2: Formula I-1; Formula I-2.

3. The perovskite solar cell according to claim 1 or 2, characterized in that, The hole transport material satisfies at least one of the following conditions: (1) The HOMO energy level of the hole transport material is -5.25eV to -5.3eV; (2) The thermal decomposition temperature of the hole transport material is 310℃~335℃.

4. A method for fabricating a perovskite solar cell, characterized in that, Includes the following steps: A first charge transport layer, a perovskite absorption layer, and a second charge transport layer are sequentially formed on a transparent conductive electrode. The first or second charge transport layer includes a hole transport material. The method for preparing the hole transport material includes the following steps: The first coupling reaction between compound a and compound b produces compound c. In the presence of an organolithium reagent, compound c undergoes a substitution reaction with an organotin halide compound to generate compound d; The compound of formula d undergoes a second coupling reaction with the compound of formula e to generate the compound of formula I. Formula a; Formula b; Formula c; Formula d; Formula e; Formula I.

5. The method for preparing a perovskite solar cell according to claim 4, characterized in that, Includes at least one of the following features: (1) The coupling reaction between compound a and compound b includes the following steps: The first coupling reaction occurs when the compound of formula a, the compound of formula b, the first catalyst, the first base agent, and the first solvent are mixed. (2) In the presence of an organolithium reagent, the compound of formula c undergoes a substitution reaction with an organotin halide compound, including the following steps: A mixture of compound C and a second solvent is added, along with an organolithium reagent to lithiate the compound C, and then the organotin halide compound is added to induce a substitution reaction. (3) The coupling reaction between the compound of formula d and the compound of formula e includes the following steps: The second coupling reaction occurs when the compound of formula d, the compound of formula e, the third catalyst, and the third solvent are mixed.

6. The method for preparing a perovskite solar cell according to claim 5, characterized in that, Includes at least one of the following features: (1) The molar ratio of compound a to compound b is 1:(1.1~2); (2) The first catalyst comprises tetra(triphenylphosphine)palladium; (3) The first alkaline agent includes potassium carbonate; (4) The first solvent includes at least one of toluene, ethanol and water; (5) The temperature of the first coupling reaction is 80℃~90℃; (6) The first coupling reaction takes 6h to 12h.

7. The method for preparing a perovskite solar cell according to claim 5, characterized in that, Includes at least one of the following features: (1) The organolithium reagent includes n-butyllithium; (2) The organotin halide compound includes trimethyltin chloride; (3) The second solvent includes tetrahydrofuran; (4) The reaction conditions for lithiation of the compound of formula c include: reacting at -80℃ to -76℃ for 0.5 to 1.5 h, and then reacting at 10℃ to 40℃ for 20 min to 1 h; (5) The reaction conditions for the substitution reaction include: reacting at -80℃ to -76℃ for 10 min to 20 min, and then reacting at 10℃ to 40℃ for 0.5 to 1.5 h.

8. The method for preparing a perovskite solar cell according to claim 5, characterized in that, Includes at least one of the following features: (1) The molar ratio of compound d to compound e is 1:(2.2~3); (2) The third catalyst comprises tetra(triphenylphosphine)palladium; (3) The third solvent includes toluene; (4) The temperature of the second coupling reaction is 110℃~120℃; (5) The second coupling reaction takes 36h to 50h.

9. A stacked battery, characterized in that, It includes a top cell and a bottom cell stacked together, the top cell including at least one perovskite solar cell, the perovskite solar cell being as described in any one of claims 1 to 3, or being prepared by the preparation method of any one of claims 4 to 8.

10. A photovoltaic module, characterized in that, The invention includes perovskite solar cells according to any one of claims 1 to 3, or perovskite solar cells prepared by the preparation method according to any one of claims 4 to 8, or tandem cells according to claim 9.

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