Hole transport layer, preparation method thereof, perovskite solar cell and electric device

Abstract

The application relates to the technical field of solar cells, in particular to a hole transport layer and a preparation method thereof, a perovskite solar cell and an electric device. The hole transport layer comprises a carbazole-based self-assembled monomer, rhodanine and / or a derivative thereof. The application introduces rhodanine and / or the derivative thereof into the hole transport layer containing the carbazole-based self-assembled monomer, and during a subsequent perovskite film forming process, the C=O group and the C=S group in the rhodanine and / or the derivative thereof and uncoordinated Pb 2+ strong coordination occurs, interface deep energy level defects are passivated, non-radiative recombination is inhibited, and the performance and stability of the device are improved. Meanwhile, the rhodanine and / or the derivative thereof has a pi-conjugated structure, when the rhodanine and / or the derivative thereof is located between the carbazole-based self-assembled monomer and the perovskite layer, the pi-conjugated structure can form effective electronic coupling with the perovskite and the carbazole-based self-assembled monomer, the coupling effect cooperates with the interface defect passivation function to improve the energy level alignment of the interface and improve the hole transfer efficiency.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to hole transport layers and their preparation methods, perovskite solar cells, and electrical devices. Background Technology

[0002] Perovskite solar cells (PSCs) have become a research hotspot in the photovoltaic field due to their advantages such as high photoelectric conversion efficiency, low cost, and solution-based fabrication.

[0003] Carbazole-based self-assembled monomolecules (MAMs) possess the advantages of tunable energy levels, high coverage, and simple preparation, making them widely used in hole transport layers in perovskite solar cells. However, MAMs exhibit low solubility in alcohol solvents commonly used for preparing hole transport layers, and the terminal groups of MAMs are highly hydrophobic, making it difficult to form a uniform and dense film on the substrate. This hinders the deposition of a high-quality perovskite layer, induces numerous interface defects, and creates centers for non-radiative recombination, severely restricting efficient charge extraction and transport, ultimately leading to device performance degradation and decreased long-term stability. Summary of the Invention

[0004] Based on this, the main objective of this application is to provide a hole transport layer and its preparation method, a perovskite solar cell, and an electrical device, by introducing rotannin and / or its derivatives into a carbazole-based self-assembled monomolecule to passivate the deep-level traps at the interface between the hole transport layer and the perovskite layer, thereby improving device performance and stability.

[0005] The first aspect of this application provides a hole transport layer comprising a carbazole self-assembled monomolecule, rotannin, and / or its derivatives.

[0006] In some embodiments, the carbazoyl self-assembled monomers include [4-(3,6-dimethyl-9H-carbazo-9-yl)butyl]phosphonic acid, [4-(3,6-dimethoxy-9H-carbazo-9-yl)butyl]phosphonic acid, [2-(9H-carbazo-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethoxy-9H-carbazo-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethoxy-9H-carbazo-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethyl ... [4-(9H-carbazole-9-yl)ethyl]phosphonic acid, [4-(7H-dibenzocarbazole-7-yl)butyl]phosphonic acid, [2-(9-bromocarbazole-9-yl)ethyl]phosphonic acid, [2-(9-chlorocarbazole-9-yl)ethyl]phosphonic acid, [4-(9-bromocarbazole-9-yl)butyl]phosphonic acid, and [4-(9-fluorocarbazole-9-yl)butyl]phosphonic acid.

[0007] In some embodiments, the derivatives of rotannin include one or more of rotannin, 3-benzylrotannin, and 5-vinylrotannin.

[0008] In some embodiments, the mass ratio of carbazole self-assembled monomolecules and rotannin and / or its derivatives in the hole transport layer is 1:(0.1~0.5).

[0009] The second aspect of this application provides a method for preparing a hole transport layer, comprising the following steps: mixing a carbazole self-assembled monomolecule, rotannin and / or its derivatives with a solvent to prepare a mixed solution; coating the mixed solution onto a substrate and annealing it to obtain a hole transport layer.

[0010] In some embodiments, the step of mixing a carbazole-based self-assembled monomolecule, rotannin, and / or its derivatives with a solvent includes: mixing the carbazole-based self-assembled monomolecule with a first solvent to prepare a first solution; mixing rotannin and / or its derivatives with a second solvent to prepare a second solution; and mixing the first solution and the second solution to prepare a mixed solution; wherein the first solvent and the second solvent are each independently selected from alcohol solvents.

[0011] In some embodiments, the annealing process satisfies at least one of the following conditions: (1) the annealing temperature is 50°C to 150°C; (2) the annealing time is 3 min to 30 min.

[0012] The third aspect of this application provides a perovskite solar cell, including the hole transport layer provided in the first aspect of this application or the hole transport layer prepared by the method provided in the second aspect of this application.

[0013] In some embodiments, a perovskite solar cell includes a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, a buffer layer, and a metal electrode, which are stacked sequentially.

[0014] The fourth aspect of this application provides an electrical device, including the perovskite solar cell provided in the third aspect of this application.

[0015] Compared to traditional technologies, this application has at least the following advantages: By introducing rotannin and / or its derivatives into the hole transport layer of a carbazole-containing self-assembled monomolecule, the C=O and C=S groups in rotannin and / or its derivatives act as Lewis bases during the subsequent perovskite film formation process, reacting with uncoordinated Pb in the perovskite layer. 2+Strong coordination occurs, filling coordination vacancies, passivating deep-level defects at the interface, suppressing nonradiative recombination, and improving device performance and stability. Simultaneously, if tannin and / or its derivatives possess a π-conjugated structure, when located between a carbazole-based self-assembled monomolecule and the perovskite layer, this π-conjugated structure can form effective electronic coupling with both the perovskite and carbazole-based self-assembled monomolecules. This coupling, combined with its interface defect passivation function, can improve interface energy level alignment, lower the hole extraction barrier, reduce charge accumulation and recombination at the interface, and improve the hole transfer efficiency from the perovskite layer to the hole transport layer. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying 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.

[0017] Figure 1 This is a schematic diagram of a method for preparing a hole transport layer according to one embodiment of this application.

[0018] Figure 2 This is a schematic diagram of a perovskite solar cell according to one embodiment of this application.

[0019] Explanation of reference numerals in the attached figures: 1. Perovskite solar cell; 10. Transparent conductive substrate; 20. Hole transport layer; 30. Perovskite layer; 40. Electron transport layer; 50. Buffer layer; 60. Metal electrode. Detailed Implementation

[0020] A detailed reference is now provided to embodiments of this application, one or more of which are described below. Each embodiment is provided for explanation and not for limitation. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to this application without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0021] Therefore, this application is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents. Other objects, features, and aspects of this application are disclosed in or will be apparent from the following detailed description. It will be understood by those skilled in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of this application.

[0022] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0023] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0024] Unless otherwise specified herein, all embodiments and optional embodiments of this application can be combined with each other to form new technical solutions. Similarly, unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form new technical solutions.

[0025] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0026] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0027] Unless otherwise stated or in case of conflict, the terms or phrases used in this application shall have the following meanings:

[0028] In this application, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" or "at least one" means one or more of two.

[0029] In this application, terms such as "further" and "especially" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0030] In this application, when numerical intervals (i.e., numerical ranges) are mentioned, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include numerical interval types such as percentage intervals, ratio intervals, and proportion intervals.

[0031] A first aspect of this application provides a hole transport layer 20 comprising a carbazole self-assembled monomolecule, rotannin, and / or its derivatives.

[0032] It should be noted that the rotannin in this application, also known as rhodanine or ratanine, is an organic compound, and the structural formula of rotannin is shown in formula (I) below.

[0033]

[0034] Formula (I).

[0035] This application introduces rotannin and / or its derivatives into carbazole-based self-assembled monomers. During subsequent perovskite film formation, the C=O and C=S groups in rotannin and / or its derivatives act as Lewis bases, interacting with uncoordinated Pb in the perovskite layer 30. 2+ Strong coordination occurs, filling coordination vacancies, passivating deep-level defects at the interface, suppressing nonradiative recombination, and improving device performance and stability. Simultaneously, if tannin and / or its derivatives possess a π-conjugated structure, when located between the carbazole-based self-assembled monomolecule and the perovskite layer 30, its π-conjugated structure can form effective electronic coupling with both the perovskite and carbazole-based self-assembled monomolecules. This coupling, combined with its interface defect passivation function, can improve interface energy level alignment, lower the hole extraction barrier, reduce charge accumulation and recombination at the interface, and improve the hole transfer efficiency from the perovskite layer 30 to the hole transport layer 20.

[0036] In some embodiments, the carbazoyl self-assembled monomers include [4-(3,6-dimethyl-9H-carbazo-9-yl)butyl]phosphonic acid, [4-(3,6-dimethoxy-9H-carbazo-9-yl)butyl]phosphonic acid, [2-(9H-carbazo-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethoxy-9H-carbazo-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethoxy-9H-carbazo-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethyl ... [4-(9H-carbazole-9-yl)ethyl]phosphonic acid, [4-(7H-dibenzocarbazole-7-yl)butyl]phosphonic acid, [2-(9-bromocarbazole-9-yl)ethyl]phosphonic acid, [2-(9-chlorocarbazole-9-yl)ethyl]phosphonic acid, [4-(9-bromocarbazole-9-yl)butyl]phosphonic acid, and [4-(9-fluorocarbazole-9-yl)butyl]phosphonic acid.

[0037] In some embodiments, the derivatives of rotannin include one or more of rotannin, 3-benzylrotannin, and 5-vinylrotannin. Further, the derivative of rotannin is 3-benzylrotannin.

[0038] On the one hand, due to its hydrophobicity and poor solubility in conventional alcohol solvents, carbazole-based monomolecules tend to form discontinuous and aggregated non-uniform films on the transparent conductive substrate 10. By introducing 3-benzylrhodanine into the carbazole-based self-assembled monomolecules, the benzyl aromatic ring interacts with the carbazole group via π-π stacking, which alleviates the problem of uneven arrangement of carbazole-based monomolecules and induces the formation of a denser and flatter hole transport layer 20. Simultaneously, the hydrophilic rhodanine core enhances its compatibility and solubility in polar alcohol solvents, not only making the solution coating more uniform and contributing to the formation of a more uniform and dense hole transport layer 20 on the substrate surface, but also improving the wettability of the hole transport layer 20 surface, allowing the perovskite precursor solution to spread better on the hole transport layer 20 surface, laying the foundation for the deposition of a high-quality, large-grained, low-defect-density perovskite layer 30.

[0039] On the other hand, by introducing 3-benzyl rotannin into the carbazole self-assembled monomolecule, the benzyl group forms a local hydrophobic barrier at the interface, preventing water molecules in the environment from eroding the perovskite layer 30, thus improving the long-term stability of the device.

[0040] In some embodiments, the mass ratio of carbazole self-assembled monomolecules and rotannin and / or its derivatives in the hole transport layer 20 is 1:(0.1~0.5), including 1:0.1, 1:0.2, 1:0.3, 1:0.4, and 1:0.5.

[0041] like Figure 1 As shown, a second aspect of this application provides a method for preparing a hole transport layer 20, comprising the following steps:

[0042] S1. Prepare a mixed solution by mixing carbazole self-assembled monomolecules, rotannin and / or its derivatives with a solvent.

[0043] S2. The mixed solution is coated on the substrate and annealed to obtain the hole transport layer 20.

[0044] In some embodiments, the step of mixing the carbazole self-assembled monomolecule, rotannin, and / or its derivatives with a solvent in S1 above includes:

[0045] S10. Mix the carbazole self-assembled monomolecule with the first solvent to prepare the first solution.

[0046] S20. Mix rutin and / or its derivatives with a second solvent to prepare a second solution.

[0047] S30. Mix the first solution and the second solution to prepare a mixed solution.

[0048] In some embodiments, the first solvent and the second solvent are each independently selected from alcohol solvents, and the first solvent and the second solvent may be the same or different.

[0049] In some embodiments, the alcohol solvent includes one or more of methanol, ethanol, and isopropanol.

[0050] In some embodiments, the mass concentration of carbazole self-assembled monomers in the mixed solution is 0.2 mg / mL to 0.8 mg / mL, including 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL, 0.5 mg / mL, 0.6 mg / mL, 0.7 mg / mL, and 0.8 mg / mL.

[0051] In some embodiments, the mass concentration of rutin and / or its derivatives in the mixed solution is 0.02 mg / mL to 0.4 mg / mL, including 0.02 mg / mL, 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, and 0.4 mg / mL.

[0052] It is understood that this application does not specifically limit the method of coating the mixed solution on the substrate. Under the premise of satisfying the overall inventive concept of this application, any known coating method can be applied in this application. The following are only examples, which are spin coating, blade coating or slot coating methods can be used to coat the mixed solution on the substrate.

[0053] In one specific embodiment, in S2 above, the mixed solution is coated onto the substrate by spin coating and then annealed to obtain the hole transport layer 20.

[0054] In some embodiments, the annealing temperature is 50°C to 150°C, including 50°C, 80°C, 100°C, 120°C, and 150°C.

[0055] In some implementations, the annealing time is 3 min to 30 min, including 3 min, 10 min, 15 min, 20 min, 25 min, and 30 min.

[0056] The third aspect of this application provides a perovskite solar cell 1, including the hole transport layer 20 provided in the first aspect of this application or the hole transport layer 20 prepared by the method provided in the second aspect of this application.

[0057] In some implementations, such as Figure 2 As shown, the perovskite solar cell 1 includes a transparent conductive substrate 10, a hole transport layer 20, a perovskite layer 30, an electron transport layer 40, a buffer layer 50, and a metal electrode 60, which are stacked sequentially.

[0058] In some embodiments, the transparent conductive substrate 10 includes one or more of ITO, IZO, IWO, ICO, FTO, and AZO.

[0059] In a specific example, the transparent conductive substrate 10 is an FTO substrate.

[0060] In some embodiments, the perovskite layer 30 is made of a perovskite-type metal halide; the chemical formula of the perovskite-type metal halide is ABX3; wherein A is a monovalent cation, B is a divalent cation, and X is a monovalent anion. A includes Cs + K + 、Rb + One or more of monovalent amine cations and monovalent amido cations. Non-limiting examples of monovalent amine cations include CH3NH3. + (Methylamine, MA) + ), ammonium (NH4) + Non-limiting examples of monovalent amidine cations include NH₂CH=NH₂. + (Formamidin, FA) + B includes Pb. 2+ Sn 2+ Fe 2+ Mn 2+ Ni 2+ 、Ge 2+ Co 2+ and Sb 2+ One or more of these. X includes I. - ,Br - and Cl - One or more of them.

[0061] In some implementations, the electron transport layer 40 is an n-type semiconductor.

[0062] In a specific example, the material of electron transport layer 40 includes C60 and / or PCBM.

[0063] In one specific example, the material of the buffer layer 50 includes SnO2 and / or BCP (Bathocuproine, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline).

[0064] In some embodiments, the material of the metal electrode 60 includes one or more of Cu, Al, Ag, and Au.

[0065] The fourth aspect of this application provides an electrical device including the perovskite solar cell 1 provided in the third aspect of this application.

[0066] The implementation schemes of this application will be described in detail below with reference to specific embodiments. It should be understood that these embodiments are only for illustrating this application and are not intended to limit the scope of this application. For experimental methods in the following embodiments where specific conditions are not specified, the guidance given in this application should be followed first, or experimental manuals or conventional conditions in the art can be used, or conditions recommended by the manufacturer can be used, or experimental methods known in the art can be referenced. Unless otherwise specified, the raw materials used in the following experiments can all be routinely purchased from the market.

[0067] Example 1 provides a method for fabricating a perovskite solar cell.

[0068] 1) Pretreatment of transparent conductive substrate: FTO glass is placed in an ultrasonic cleaner and ultrasonically cleaned with deionized water, ethanol, acetone and isopropanol in sequence. Each cleaning step takes 10 minutes. The glass is then dried with a nitrogen (N2) gas gun and treated with UV-zone (ultraviolet ozone) for 20 minutes to prepare the substrate for use.

[0069] 2) Hole transport layer preparation: 3-Benzylrhodanine was weighed and dissolved in anhydrous ethanol, stirred until completely dissolved, to prepare a first solution with a concentration of 0.5 mg / mL; Me-4PACz ([4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid) was weighed and dissolved in anhydrous ethanol, stirred until completely dissolved, to prepare a second solution with a concentration of 0.5 mg / mL; the first and second solutions were mixed to prepare a mixed solution, in which the concentration of 3-benzylrhodanine was 0.05 mg / mL and the concentration of Me-4PACz was 0.3 mg / mL. The mixed solution was then spin-coated onto the substrate at a coating speed of 3000 rpm for 30 seconds, and annealed at 100℃ for 10 minutes to form a hole transport layer with a thickness of 1 nm-2 nm. The mass ratio of Me-4PACz to 3-benzylrhodanine in the hole transport layer was 1:0.3.

[0070] 3) Perovskite layer preparation: 1.6 mol of FAPbI3 was dissolved in 1 mL of a solvent consisting of DMF and DMSO in a volume ratio of 4:1. The solution was stirred for 2 h to obtain a perovskite precursor solution. A one-step spin-coating method was used to spin-coat the perovskite precursor solution onto the hole transport layer at a coating speed of 5000 rpm for 30 s. 15 s before the end of the spin-coating deposition, 300 μL of chlorobenzene was rapidly added dropwise to the surface of the perovskite layer to form a wet perovskite film. The film was then annealed at 150 °C for 15 min to form a perovskite layer with a thickness of 500 nm.

[0071] 4) Electron transport layer preparation: A C60 (fullerene) layer with a thickness of 30 nm was deposited on the perovskite layer at a rate of 0.5 Å / s as an electron transport layer.

[0072] 5) Buffer layer preparation: A 6 nm thick BCP (Bathocuproine, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) layer was deposited on the electron transport layer at a rate of 0.5 Å / s as a buffer layer.

[0073] 6) Metal electrode preparation: A silver (Ag) electrode with a thickness of 110 nm was deposited on the buffer layer using a thermal evaporation coating method to complete the preparation of the perovskite solar cell.

[0074] Example 2

[0075] The preparation process of this embodiment is basically the same as that of Example 1. The main difference is that the rutin and / or its derivatives in this embodiment are rutin.

[0076] Example 3

[0077] The preparation process of this embodiment is basically the same as that of Example 1. The main difference is that the rotannin and / or its derivatives in this embodiment are 5-vinylrotannin.

[0078] Example 4

[0079] The preparation process of this embodiment is basically the same as that of Example 1. The main difference is that the mass ratio of Me-4PACz and 3-benzylrhodanine in the hole transport layer in this embodiment is 1:0.05.

[0080] Example 5

[0081] The preparation process of this embodiment is basically the same as that of Example 1. The main difference is that the mass ratio of Me-4PACz and 3-benzylrhodanine in the hole transport layer in this embodiment is 1:0.1.

[0082] Example 6

[0083] The preparation process of this embodiment is basically the same as that of Example 1. The main difference is that the mass ratio of Me-4PACz to 3-benzylrhodanine in the hole transport layer in this embodiment is 1:0.5.

[0084] Example 7

[0085] The preparation process of this embodiment is basically the same as that of Example 1. The main difference is that the mass ratio of Me-4PACz to 3-benzylrhodanine in the hole transport layer in this embodiment is 1:0.8.

[0086] Comparative Example 1

[0087] The preparation process of this embodiment is basically the same as that of Embodiment 1. The main difference is that the hole transport layer in this comparative embodiment only includes Me-4PACz.

[0088] Test case

[0089] Using a solar simulator and a Keithley 2400 source meter, the open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and initial power conversion efficiency (PCE) of perovskite solar cells were tested under a single solar radiation intensity. Performance tests were performed on the perovskite solar cell modules prepared in the examples and comparative examples; the results are shown in Table 1.

[0090] Table 1

[0091] Voc (V) Jsc (mA / cm²) FF (%) PCE (%) Example 1 1.13 24.82 88.63 24.86 Example 2 1.12 24.16 85.14 23.05 Example 3 1.12 24.21 83.83 22.73 Example 4 1.13 23.13 82.56 21.58 Example 5 1.13 23.79 85.66 23.03 Example 6 1.13 23.35 86.25 22.76 Example 7 1.13 23.50 80.79 21.50 Comparative Example 1 1.12 23.35 79.52 20.80

[0092] As can be seen from Table 1, compared with the comparative examples, the absolute value of the photoelectric conversion efficiency (PCE) of the batteries prepared by introducing rotannin and / or its derivatives into carbazole self-assembled monomolecules in Examples 1-7 was significantly improved.

[0093] The potential for improved battery performance is speculated as follows: If tannin and / or its derivatives are successfully doped into the carbazole-based self-assembled monomolecular hole transport layer, and if the carbonyl groups (C=O) and thiocarbonyl groups (C=S) in tannin and / or its derivatives effectively passivate the uncoordinated Pb at the perovskite bottom boundary during subsequent perovskite film formation... 2+ The defects inhibited interfacial nonradiative recombination, thereby improving Voc; at the same time, the blending of rotannin and / or its derivatives with carbazole self-assembled monomolecules improved the film-forming properties and surface wettability of the hole transport layer, promoted the formation of larger and denser perovskite grains, and thus improved Jsc and FF.

[0094] 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.

[0095] The above embodiments merely illustrate 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 patent application. 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 method for preparing a hole transport layer, characterized in that, Includes the following steps: A mixed solution was prepared by mixing a carbazole self-assembled monomolecule, rotannin and / or its derivatives with a solvent. The mixed solution was coated onto a substrate and then annealed to obtain the hole transport layer. The structural formula of the rutin is shown in equation (I) below: Formula (I); The derivatives of rotannin include one or more of 3-benzylrotannin and 5-vinylrotannin; The mass ratio of the carbazole self-assembled monomolecule and the rotannin and / or its derivative in the hole transport layer is 1:(0.1~0.5). The hole transport layer is used in lead-containing perovskite solar cells.

2. The method for preparing a hole transport layer according to claim 1, characterized in that, The steps of mixing carbazole self-assembled monomolecules, rotannins and / or their derivatives with a solvent include: The carbazole self-assembled monomolecule is mixed with a first solvent to prepare a first solution; A second solution is prepared by mixing the rutin and / or its derivatives with a second solvent; The first solution and the second solution are mixed to prepare the mixed solution; The first solvent and the second solvent are each independently selected from alcohol solvents.

3. The method for preparing a hole transport layer according to claim 1, characterized in that, The annealing process satisfies at least one of the following conditions: (1) The annealing temperature is 50℃~150℃; (2) The annealing time is 3 min to 30 min.

4. The method for preparing a hole transport layer according to claim 1, characterized in that, The carbazolyl self-assembled monomers include [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid, [4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid, [2-(9H-carbazol-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethyl ... [4-(9H-carbazole-9-yl)ethyl]phosphonic acid, [4-(7H-dibenzocarbazole-7-yl)butyl]phosphonic acid, [2-(9-bromocarbazole-9-yl)ethyl]phosphonic acid, [2-(9-chlorocarbazole-9-yl)ethyl]phosphonic acid, [4-(9-bromocarbazole-9-yl)butyl]phosphonic acid and [4-(9-fluorocarbazole-9-yl)butyl]phosphonic acid.

5. A hole transport layer, characterized in that, The hole transport layer is prepared using the method described in any one of claims 1-4.

6. A perovskite solar cell, characterized in that, The hole transport layer includes the hole transport layer prepared by the method described in any one of claims 1 to 4, or the hole transport layer described in claim 5.

7. The perovskite solar cell according to claim 6, characterized in that, The perovskite solar cell comprises a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, a buffer layer, and a metal electrode, which are stacked sequentially.

8. An electrical device, characterized in that, Including the perovskite solar cell as described in claim 6 or 7.

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