Surface modification layer, surface modification solution, self-assembled composite layer and battery thereof

Abstract

The invention provides a surface modification layer of a self-assembled monolayer (SAM), a surface modification solution, a self-assembled composite layer and a battery thereof. The material of the surface modification layer comprises a compound as shown in a formula A. According to the invention, the molecular layer is assembled after the SAM surface is deposited by adopting the compound in the formula A, so that gaps among SAM molecules can be effectively filled, and the surface wettability of the SAM is improved.

Description

Technical Field

[0001] The invention relates to the field of perovskite solar cells, and in particular to a surface modification layer, a surface modification solution, a self-assembled composite layer and a battery thereof. Background Art

[0002] At present, the efficiency of perovskite solar cells has reached 26.7%, and this efficiency is also achieved thanks to the development of self-assembled monolayers. However, self-assembled monolayers (SAMs) still have a lot of problems, such as poor wettability, molecular clusters, energy level mismatch, etc. These are problems that need to be solved urgently.

[0003] Recently, Snaith et al. introduced 4,4'4"-triphenylamine tricarboxylate (NA) molecules into [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid (Me-4PACz), which effectively improved the wettability of the self-assembled monolayer, reduced the clustering of Me-4PACz, and released the residual stress at the bottom interface. The final certification efficiency was as high as 26.54%.

[0004] Sargent et al. formed a mixed SAM by mixing 3-mercaptopropionic acid (3-MPA) molecules into [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), which effectively decomposed high-order clusters and homogenized the distribution of phosphonic acid molecules, minimizing interface recombination and improving the electronic structure, with a final certified efficiency of 24.8%.

[0005] At present, most of the modifications to the SAM layer come from body doping of the SAM. Although this method can improve the wettability of the SAM, body doping has low repeatability and high solubility requirements, and can only improve the wettability of the SAM to a certain extent. Summary of the invention

[0006] In view of the problems existing in the above-mentioned prior art, the present invention provides a surface modification layer of a self-assembled monolayer, a surface modification solution, a self-assembled composite layer and a battery thereof. By using the surface modification layer prepared by the compound of formula A of the present invention to modify the surface of the self-assembled monolayer, the interface wettability can be effectively improved, and the molecular gaps on the surface of the self-assembled monolayer can be effectively filled, thereby optimizing the transmission efficiency of electrons between interfaces, reducing non-radiative recombination between interfaces and buried interface defects, and also optimizing the energy band arrangement.

[0007] The first aspect of the present invention provides a surface modification layer of a self-assembled monolayer, wherein the material of the surface modification layer comprises a compound of formula A, and the structure of the compound of formula A is as follows:

[0008]

[0009] Wherein, R1 and R2 are each independently selected from a covalent bond, a C1-C10 alkylene group and a halogen-substituted C1-C10 alkylene group.

[0010] In one or more embodiments, R1 and R2 are each independently selected from C1-4 alkyl and halogen-substituted C1-C4 alkylene.

[0011] In one or more embodiments, the halogen-substituted C1-4 alkyl is 1-10 or 1-5 halogen-substituted C1-4 alkyl.

[0012] In one or more embodiments, the compound of formula A is 3-amino-5-mercapto-1,2,4-triazole, and its structural formula is:

[0013]

[0014] In one or more embodiments, the material of the self-assembled monolayer is selected from one or more of Me-4PACz ((4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid), MeO-4PACz (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid) and 2PACz (2-[(2-chlorophenyl)(phenyl)amino]benzoic acid ethyl ester).

[0015] The second aspect of the present invention provides a surface modification solution, which comprises a compound of formula A as described in any embodiment herein and a solvent.

[0016] In one or more embodiments, the solvent is one or more of isopropanol, ethanol, methanol, and N,N-dimethylformamide.

[0017] In one or more embodiments, the concentration of the compound of formula A in the surface modification solution is 0.1 mg / mL-10 mg / mL.

[0018] The third aspect of the present invention provides a method for preparing a surface modification layer as described in any embodiment of the present invention, the method comprising the following steps:

[0019] The surface modification solution as described in any embodiment of the present invention is coated on the surface of the self-assembled monolayer, and then annealed to obtain the surface modification layer.

[0020] In one or more embodiments, the material of the self-assembled monolayer is selected from one or more of Me-4PACz, MeO-4PACz and 2PACz.

[0021] In one or more embodiments, the coating method includes one or more processes of spin coating, slit coating, doctor blading, spray coating, screen printing, and inkjet printing.

[0022] In one or more embodiments, the annealing temperature is 100-150° C., and the annealing time is 8-30 min.

[0023] A fourth aspect of the present invention provides a self-assembled composite layer, comprising a self-assembled monolayer and a surface modification layer located on the surface of the self-assembled monolayer, wherein the surface modification layer is as described in any embodiment herein.

[0024] In one or more embodiments, the material of the self-assembled monolayer is selected from one or more of Me-4PACz, MeO-4PACz and 2PACz.

[0025] A fifth aspect of the present invention provides a perovskite solar cell comprising a self-assembled composite layer as described in any embodiment of the present invention.

[0026] The sixth aspect of the present invention provides the use of the compound of formula A according to any embodiment of the present invention in improving the interfacial wettability of self-assembled monolayer materials and filling the molecular gaps on the surface of the self-assembled monolayer.

[0027] A seventh aspect of the present invention provides the use of a compound of formula A according to any embodiment of the present invention in the preparation of a perovskite solar cell with improved photovoltaic performance.

[0028] The eighth aspect of the present invention provides the use of the surface modification layer as described in any embodiment of the present invention in improving the interface wettability of the self-assembled monolayer material and filling the molecular gaps on the surface of the self-assembled monolayer.

[0029] A ninth aspect of the present invention provides the use of a surface modification layer as described in any embodiment herein in the preparation of a perovskite solar cell with improved photovoltaic performance.

[0030] Beneficial effects of the present invention:

[0031] By using the compound of formula A of the present invention to perform secondary deposition on the surface of a SAM (self-assembled monolayer) and then assemble a molecular layer, the gaps between SAM molecules are effectively filled, the wettability of the SAM surface is improved, the transmission efficiency of electrons between interfaces is optimized, the non-radiative composite recombination between interfaces is reduced, and the energy band arrangement can also be optimized. At the same time, the amino group can coordinate with the Pb of the lower interface to effectively passivate the defects of the lower interface, further improve the carrier transmission, and improve the device performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Graphs showing contact angles of the perovskites of Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in this article. Unless otherwise specified, all technical and scientific terms used in this article are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definitions in this article shall prevail.

[0034] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0035] Herein, “comprising”, “including”, “containing” and similar terms encompass the meanings of “consisting essentially of” and “consisting of”. For example, when “A comprises B and C” is disclosed herein, “A consists essentially of B and C” and “A consists of B and C” should be deemed to be disclosed herein.

[0036] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0037] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0038] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0039] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this document.

[0040] In this paper, self-assembled monolayers are referred to as SAM.

[0041] The purpose of the present invention is to provide a surface modification layer of a SAM layer, a surface modification solution, a self-assembled composite layer and a battery thereof. The surface modification layer is obtained by performing secondary deposition on the surface of the SAM layer using the compound of formula A of the present invention and then assembling a molecular layer, which can effectively fill the gaps between SAM molecules, improve the wettability of the SAM surface, optimize the transmission efficiency of electrons between interfaces, reduce non-radiative composite recombination between interfaces, and also optimize the energy band arrangement. At the same time, the amino group can coordinate with the Pb of the lower interface, effectively passivate the defects of the lower interface, further improve the carrier transmission, and improve the device performance.

[0042] In the present invention, the compound of formula A has the following structure:

[0043]

[0044] Wherein, R1 and R2 are each independently selected from a covalent bond, a C1-C10 alkylene group and a halogen-substituted C1-C10 alkylene group.

[0045] In some embodiments, the compound of formula A, 3-amino-5-mercapto-1,2,4-triazole, has the structural formula:

[0046]

[0047] In some embodiments, the compound of formula A and a solvent are mixed to obtain a surface modification solution. The type of solvent is not particularly limited, and can be selected from organic solvents conventionally used in the art, such as one or more selected from isopropanol, ethanol, methanol and N,N-dimethylformamide.

[0048] In some embodiments, the mass concentration of the compound of formula A in the surface hole modification solution is 0.1 mg / ml-10 mg / ml, such as 0.1-0.5 mg / ml or 2-5 mg / ml.

[0049] In some embodiments, the compound of formula A is 3-amino-5-mercapto-1,2,4-triazole.

[0050] The present invention also provides a method for preparing a surface modification layer, which comprises the following steps: coating a surface modification solution on the surface of a self-assembled monolayer, and annealing to obtain the surface modification layer; wherein the surface modification solution contains a solvent and the compound of formula A described herein.

[0051] In some embodiments, the material of the self-assembled monolayer can be selected from one or more of Me-4PACz ((4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid), MeO-4PACz (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid), and 2PACz (2-[(2-chlorophenyl)(phenyl)amino]benzoic acid ethyl ester).

[0052] In the present invention, in some embodiments, the surface modification solution is coated on the surface of the SAM layer using a slit coating process. The coating thickness of the surface modification solution on the surface of the SAM layer can be adjusted according to the target thickness of the surface modification layer. In the slit coating process, the coating rate can be 15-20 mm / s. The injection rate can be 10-14 ul / s. The coating interval can be 65-75 μm.

[0053] In the present invention, the coating method may also include one or more processes of spin coating, scraping, spraying, screen printing, and inkjet printing. The parameters of these processes may be adjusted according to the target thickness of the surface modification layer.

[0054] After coating, annealing is performed. The purpose of annealing is to remove the solvent and optimize the SAM arrangement. The annealing temperature is 100-150°C, such as 100-110°C. An exemplary annealing time may be 8-30 minutes. It may be placed on a hot stage, such as 100-110°C, for annealing for 9-12 minutes. After annealing, a surface modification layer is obtained.

[0055] In the present invention, the thickness of the surface modification layer may be 2-5 nm.

[0056] In some embodiments, the SAM layer has a thickness of 2-5 nm.

[0057] Therefore, the present invention also provides a self-assembled composite layer, which includes a SAM layer and a surface modification layer as described herein disposed on the surface of the SAM layer.

[0058] Perovskite solar cells

[0059] The present invention also provides a perovskite solar cell, which comprises a SAM layer and a surface modification layer as described herein disposed on the surface of the SAM layer.

[0060] The present invention also provides a method for preparing a perovskite solar cell, which includes the steps of sequentially arranging a conductive layer, an electron transport layer, a SAM layer, a surface modification layer described herein, a perovskite absorption layer, an electron transport layer, a barrier layer, and an electrode on a transparent glass from bottom to top, wherein the surface modification layer described herein can be arranged using the steps for preparing the surface modification layer described herein. Optionally, a hole transport layer can also be arranged between the electron transport layer and the SAM layer.

[0061] Therefore, the perovskite solar cell of the present invention may include transparent glass, a conductive layer, an electron transport layer, a SAM layer, a surface modification layer, a perovskite absorption layer, an electron transport layer, a barrier layer and an electrode arranged in sequence from bottom to top. Optionally, a hole transport layer may also be arranged between the electron transport layer and the SAM layer.

[0062] The materials suitable for the conductive layer of the present invention include, but are not limited to, one or more of FTO, ITO, and IZO. The preparation of the conductive layer is not particularly limited, and the conventional method for preparing the conductive layer in the art can be used, such as a magnetron sputtering process. The process parameters can be adjusted according to the target thickness of the conductive oxide layer.

[0063] Materials suitable for the hole transport layer of the present invention include, but are not limited to, NiOx, SAM, and the like. The preparation of the hole transport layer is not particularly limited, and a conventional method for preparing a hole transport layer in the art may be used, such as spin coating, blade coating, or slit coating. The process parameters may be adjusted according to the target thickness of the hole transport layer. In some embodiments, the hole transport layer includes a NiOx layer.

[0064] The active material of the perovskite active layer suitable for the present invention contains ABX 3 Compound, A is a monovalent cation, for example, a mixture of one or more monovalent cations of cesium, rubidium, methylamine, and methylamidine; B is a divalent cation, for example, a mixture of one or more divalent cations of lead, copper, zinc, gallium, tin, and calcium; X is a monovalent anion, for example, a mixture of one or more monovalent anions of iodine, bromine, chlorine, fluorine, and thiocyanate ions. There is no particular limitation on the preparation of the perovskite active layer, and the conventional method for preparing the perovskite active layer in the art can be used, such as spin coating, blade coating, or slit coating. In some embodiments, the perovskite precursor solution is coated on the surface of the surface modification layer to obtain the perovskite active layer. The components of the perovskite precursor solution may include FAI, CsI, PbI 2 , CsBr, CsCl, KI, KBr, KCl, RbI, RbBr, RbCl, MAI, MABr, MACl, FABr, FACl. In some embodiments, the components of the perovskite precursor solution include FAI, CsI, PbI 2 and MACl. FAI, CsI, PbI 2 The mass ratio of MACl is preferably (150-160):(20-30):(500-510):(5-9). The concentration of the perovskite precursor solution is preferably 0.8-1.2M. In some embodiments, the perovskite precursor solution is coated on the surface of the surface modification layer in a slit coating process to obtain a perovskite active layer. The coating rate may be 25-35mm / s. The injection rate may be 25-40ul / s. The coating interval may be 75-85μm. After coating, annealing treatment may be performed to obtain a perovskite active layer. In some embodiments, the thickness of the perovskite active layer is 400-800nm ​​or 500-600nm.

[0065] Materials suitable for the electron transport layer of the present invention include, but are not limited to, C60, tin oxide, zinc oxide, titanium oxide, and the like. The preparation of the electron transport layer is not particularly limited, and conventional methods for preparing the electron transport layer in the art may be used, such as thermal evaporation or magnetron sputtering. The process parameters may be adjusted according to the target thickness of the electron transport layer. In some embodiments, the thickness of the electron transport layer is 10-30 nm, such as 13-17 nm.

[0066] Materials suitable for the barrier layer of the present invention include, but are not limited to, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and the like. The preparation of the barrier layer is not particularly limited, and a conventional method for preparing a barrier layer in the art may be used, such as a thermal evaporation process. The process parameters may be adjusted according to the target thickness of the barrier layer. In some embodiments, the thickness of the buffer layer is 1 nm-10 nm, such as 5-8 nm.

[0067] The material suitable for the electrode of the present invention can be selected from at least one of gold, silver, copper, aluminum and carbon. In some embodiments, the thickness of the electrode is 90nm-400nm, such as 150-200nm.

[0068] In some embodiments, the perovskite solar cell of the present invention is a single-junction perovskite solar cell or a tandem perovskite solar cell. Tandem perovskite solar cells exemplarily include two-terminal tandem cells, three-terminal tandem cells, and four-terminal tandem cells.

[0069] The present invention also provides the use of the compound of formula A described herein in preparing a perovskite solar cell with improved photovoltaic performance. The compound of formula A described herein can be used for thin-film solar cells including but not limited to perovskite solar cells. In the present invention, the thin-film solar cell can be conventional in the art.

[0070] The present invention will be described below in the form of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents and materials used in the examples are, unless otherwise stated, conventional methods, reagents and materials in the art. The raw material compounds in the examples can all be purchased through commercial routes.

[0071] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

[0072] Embodiment 1:

[0073] (1) Provide transparent glass with a thickness of 0.7 mm;

[0074] (2) ITO was prepared on transparent glass by magnetron sputtering with a thickness of 200 nm;

[0075] (3) NiOx was prepared by magnetron sputtering with a thickness of 15 nm;

[0076] (4) Slit coating is used to prepare the SAM layer, specifically: the SAM material Me-4PACz is dissolved in isopropanol to form a hole transport solution, and the mass concentration of the SAM material is 0.5 mg / ml. The hole transport solution is coated on the surface of the NiOx layer, and after annealing, a SAM layer is obtained; the thickness is about 2 nm;

[0077] (5) preparing a surface modification layer on the surface of the SAM layer by slit coating, specifically: mixing 3-amino-5-mercapto-1,2,4-triazole and ethanol to obtain a surface modification solution, wherein the concentration of 3-amino-5-mercapto-1,2,4-triazole is about 0.1 mg / ml. The surface modification solution is coated on the surface of the SAM layer, and after annealing, a surface modification layer is obtained. The slit coating process has a coating rate of 30 mm / s, a liquid injection rate of 18 ul / s, a gap value of 80 um, and then pre-annealing at 100°C for 10 min;

[0078] (6) FAI, CsI, PbI2, MACl (mass ratio of 155:26:508:7) were dissolved in a mixed solvent of DMF, NMP, and ACN to obtain a 1.6 M perovskite precursor solution, and perovskite was prepared as an active layer by slit coating. The slit coating process had a coating rate of 30 mm / s, a liquid injection rate of 30 ul / s, and a gap value of 80 um. Subsequently, the solution was pre-annealed at 100 °C for 2 min and annealed at 120 °C for 20 min. The thickness was about 550 nm.

[0079] (7) C60 was evaporated by heat, with a thickness of 15 nm;

[0080] (8) BCP was prepared by thermal evaporation with a thickness of 6 nm;

[0081] (9) Cu was prepared by thermal evaporation with a thickness of 180 nm.

[0082] Example 2

[0083] A solar cell was prepared according to the method of Example 1, except that the concentration of 3-amino-5-mercapto-1,2,4-triazole in step 5 was 0.5 mg / ml.

[0084] Example 3

[0085] A solar cell was prepared according to the method of Example 1, except that the concentration of 3-amino-5-mercapto-1,2,4-triazole in step 5 was 2 mg / ml.

[0086] Example 4

[0087] A solar cell was prepared according to the method of Example 1, except that the concentration of 3-amino-5-mercapto-1,2,4-triazole in step 5 was 5 mg / ml.

[0088] Example 5

[0089] A solar cell was prepared according to the method of Example 1, except that the concentration of 3-amino-5-mercapto-1,2,4-triazole in step 5 was 10 mg / ml.

[0090] Comparative Example 1

[0091] (1) Transparent glass, thickness 0.7 mm;

[0092] (2) ITO was prepared by magnetron sputtering with a thickness of 200 nm;

[0093] (3) Preparation of NiO by magnetron sputtering X , thickness is 15nm;

[0094] (4) Slit coating is used to prepare the SAM layer, specifically: the SAM material Me-4PACz is dissolved in isopropanol to form a hole transport solution, and the mass concentration of the SAM material is 0.5 mg / ml. The hole transport solution is coated on the surface of the NiOx layer, and after annealing, a SAM layer is obtained; the thickness is about 2 nm;

[0095] (5) Slit coating was used to prepare perovskite as the active layer with a thickness of about 550 nm;

[0096] (6) Using thermal evaporation C 60 , thickness 15nm;

[0097] (7) BCP was prepared by thermal evaporation with a thickness of 6 nm;

[0098] (8) Cu was prepared by thermal evaporation with a thickness of 180 nm.

[0099] Comparative Example 2

[0100] The difference between Comparative Example 2 and Comparative Example 1 is that in step (4), the SAM material and 3-amino-5-mercapto-1,2,4-triazole are mixed and dissolved in isopropanol to form a hole transport solution. The mass concentration of the SAM material is 0.5 mg / ml; the concentration of 3-amino-5-mercapto-1,2,4-triazole is about 0.1 mg / ml. The hole transport solution is coated on the surface of the NiOx layer and annealed to obtain a SAM layer. The thickness is about 2 nm.

[0101] Test Example 1

[0102] Photoelectric tests were performed on the perovskite solar cells prepared in Examples 1-6 and Comparative Examples 1-2. The test temperature was 25±1°C. The current density-voltage curves (JV curves) of the devices were obtained by using a source meter (Keithley 2400) under AM1.5G (100 mW / cm 2 ) obtained under illumination, the cell area is 1cm 2 ,The light intensity was calibrated by a standard silicon cell before testing, and the scanning rate was 10mV / s.

[0103] Open circuit voltage V OC is the terminal voltage of the battery in the open circuit state. SC It is the current density that a perovskite solar cell can generate under short-circuit conditions. The fill factor FF is the ratio of the maximum power of a solar cell to the product of the open circuit voltage and the short-circuit current. The photoelectric conversion efficiency PCE can be calculated by measuring the current density-voltage curve (J-V curves) of the solar cell.

[0104] The results are shown in Table 1 below.

[0105] Table 1. Photoelectric test results

[0106]

[0107] It can be seen from Table 1 that, compared with Comparative Examples 1 and 2, Examples 1-6 use the compound of formula A of the present invention to prepare the surface modification layer to modify the SAM layer, which can improve the open circuit voltage, photoelectric conversion efficiency and fill factor of the device.

[0108] Test Example 2

[0109] The contact angle between the perovskite active layer and the surface modification layer in Example 1, and the contact angle between the perovskite active layer and the SAM layer in Comparative Example 1 were measured by a vertical measurement method.

[0110] The contact angle measured is Figure 1 As shown, the left side is the contact angle diagram of the perovskite active layer and the SAM layer in comparative example 1, and the right side is the contact angle diagram of the perovskite active layer and the surface modification layer in embodiment 1. In which, the upper left corner L in the legend represents the left contact angle, R represents the right contact angle, and CA represents the average contact angle. Figure 1 It can be seen that the contact angle of the perovskite on the surface of the surface modification layer in Example 1 is much smaller than the contact angle of the perovskite on the surface of the SAM layer in Comparative Example 1.

Claims

1. A surface modification layer of a self-assembled monolayer, characterized in that: The material of the surface modification layer includes a compound of formula A, and the structure of the compound of formula A is as follows: Wherein, R1 and R2 are each independently selected from a covalent bond, a C1-C10 alkylene group and a halogen-substituted C1-C10 alkylene group.

2. The surface modification layer according to claim 1, characterized in that The compound of formula A is 3-amino-5-mercapto-1,2,4-triazole, and its structural formula is:

3. A surface modification solution, characterized in that: The surface modification solution comprises the compound of formula A as described in claim 1 or 2 and a solvent.

4. The surface modification solution according to claim 3, characterized in that The solvent is one or more of isopropanol, ethanol, methanol and N,N-dimethylformamide; and / or In the surface modification solution, the concentration of the compound of formula A is 0.1 mg / mL-10 mg / mL.

5. The method for preparing the surface modification layer as claimed in claim 1 or 2, characterized in that: The method comprises: coating the surface modification solution according to claim 3 or 4 on the surface of the self-assembled monolayer, and annealing to obtain the surface modification layer.

6. The method according to claim 5, characterized in that The method has one or more of the following features: The material of the self-assembled monolayer is selected from one or more of Me-4PACz, MeO-4PACz and 2PACz; The coating method is selected from one or more processes of spin coating, slit coating, blade coating, spray coating, screen printing and inkjet printing; The annealing temperature is 100-150° C., and the annealing time is 8-30 min.

7. A self-assembled composite layer, characterized in that: The self-assembled composite layer comprises a self-assembled monolayer and a surface modification layer located on the surface of the self-assembled monolayer, and the surface modification layer is as described in claim 1 or 2.

8. The self-assembled composite layer according to claim 7, characterized in that The material of the self-assembled monolayer is selected from one or more of Me-4PACz, MeO-4PACz and 2PACz.

9. A perovskite solar cell comprising the self-assembled composite layer according to claim 7 or 8. 10.Select from the following applications: Use of the compound of formula A as claimed in claim 1 or 2 in improving the interface wettability of self-assembled monolayer materials and filling the molecular gaps on the surface of the self-assembled monolayer; Use of the compound of formula A as claimed in claim 1 or 2 in the preparation of a perovskite solar cell with improved photovoltaic performance; Use of the surface modification layer as claimed in claim 1 or 2 in improving the interface wettability of self-assembled monolayer materials and filling the molecular gaps on the surface of the self-assembled monolayer; Use of the surface modification layer as claimed in claim 1 or 2 in the preparation of a perovskite solar cell with improved photovoltaic performance.

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