Amino acid derived co-assembly agent, mixed self-assembly monomolecular layer, preparation method of mixed self-assembly monomolecular layer and perovskite solar cell

Abstract

The invention discloses an amino acid derived co-assembly agent, a mixed self-assembly monomolecular layer, a preparation method of the mixed self-assembly monomolecular layer and a perovskite solar cell, the chemical structural general formula of the amino acid derived co-assembly agent is R-CH2-COOH, and R is guanidyl, N-substituted guanidyl or N-substituted ureido. The amino acid derived co-assembly agent has acceptor atoms and donor atoms with a plurality of hydrogen bonds, when the amino acid derived co-assembly agent is mixed with PACz molecules according to the mass ratio of 1: 0.5-1: 1, the substituent R and the PACz molecules can form multiple hydrogen bonds, a strong association effect is achieved, excessive aggregation among the PACz molecules is inhibited, and when the amino acid derived co-assembly agent is coated on a conductive oxide substrate, the PACz molecules can form multiple hydrogen bonds. The self-assembled monomolecular layer can be compactly and uniformly mixed, when the self-assembled monomolecular layer is applied to preparation of the perovskite solar cell, perovskite film defects can be passivated, energy level matching can be improved, multiple functions of anchoring enhancement, film formation improvement, defect passivation and energy level optimization are achieved, and therefore the photoelectric performance and stability of the perovskite cell are remarkably improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of interface modification of perovskite solar cells, and particularly relates to an amino acid derivative co-assembly agent, a mixed self-assembled monolayer, a preparation method thereof, and a perovskite solar cell. BACKGROUND

[0002] Self-assembled monolayers (SAMs) can be anchored on oxide (such as ITO, NiO x , SnO2) surfaces, and can realize energy level regulation and interface defect inhibition at an extremely thin scale, which is an important technical path to realize high-efficiency perovskite solar cells (PSCs). However, carbazole-phosphonic acid type representative molecules, such as [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz), are prone to form micelles and large-size aggregates in alcohol / hydrated systems, which not only reduces the effective reactivity of the phosphonic acid group with the substrate surface, but also is not conducive to obtaining uniform and dense monomolecular arrangement, and has become one of the key bottlenecks of scale coating compatibility.

[0003] Therefore, two types of ideas for improving coverage have been proposed: one is to regulate the solvation / critical micelle concentration in the solution phase by using auxiliary solvents to depolymerize the micelles of PACz type molecules, so as to restore the reaction activity of the phosphonic acid anchor and promote the growth of dense SAMs; the other is to destroy the surface phosphonic acid clustering by co-adsorbing molecules in the interface phase, and then to improve the occupation and spreading.

[0004] For example, the patent for invention with publication number CN118317668A discloses a self-assembled monolayer, a perovskite solar cell and a preparation method thereof. The preparation method of the self-assembled monolayer comprises the following steps: mixing self-assembled molecular materials with phosphonic acid as an anchor group and / or self-assembled molecular materials with carboxylic acid as an anchor group with N,N-dimethylformamide to obtain a mixed solution; and coating the mixed solution on a substrate, and obtaining the self-assembled monolayer after annealing. Compared with alcohol solvents, the method uses N,N-dimethylformamide to dissolve the self-assembled molecular materials, which can disperse the micelles formed by the self-assembled molecular materials, so that the aggregation of the surface of the prepared self-assembled monolayer is relieved, a good quality self-assembled monolayer is obtained, the coverage of the self-assembled monolayer on a large-area substrate is improved, and the wettability of the perovskite precursor solution on the substrate is improved, so that the crystallinity of the perovskite thin film is better, and the device performance is further improved.

[0005] For example, reference (Li, D., Lian, Q., Du, T. et al. Co-adsorbed self-assembled monolayer enables high-performance perovskite and organic solar cells. Nat. Commun. 15, 7605 (2024)) discloses that a small molecule 2-chloro-5-(trifluoromethyl) isonicotinic acid is combined with [2-(9H-carbazol-9-yl) ethyl] phosphonic acid to form a functionalized ultrathin layer, and through a co-adsorption strategy, the self-aggregation of the SAM can be reduced, and the efficiency and operating stability of the corresponding perovskite solar cell can be effectively improved.

[0006] However, the above-mentioned general "surface co-adsorption" strategy is not without cost: on the one hand, if the molecular compatibility between the co-adsorption molecule and the PACz molecule is limited, the inhibition of solution state micelles / aggregation is only partial; on the other hand, the competitive adsorption window of the co-adsorption molecule and the substrate site is often narrow, and slight deviation may disturb the self-assembly and orientation regulation of the PACz molecule on the surface; in addition, some formulations that rely on strong acidic anchor groups may introduce long-term stability risks of reactive oxide interfaces, and these problems have been systematically discussed in recent SAM / interface research.

[0007] Therefore, how to realize the inhibition of PACz molecules by co-adsorption molecules while ensuring that they do not interfere with the effective anchoring of PACz molecules on the substrate, and do not harm the stability of the substrate, has become a key bottleneck in the current perovskite solar cell field research and a core direction of future material engineering design. SUMMARY

[0008] In view of the deficiencies of the prior art, the first aspect of the present application provides an amino acid derivative co-assembly agent, which can inhibit the micelle formation and random aggregation phenomenon of PACz molecules from the source, and can better maintain the adsorption anchor point of PACz molecules on the substrate without damaging the stability of the substrate, thereby enhancing the photoelectric conversion performance and stability of the perovskite solar cell.

[0009] The chemical structure general formula of the amino acid derivative co-assembly agent provided by the present application is R-CH2-COOH, wherein R is guanidino, N-substituted guanidino or N-substituted urea.

[0010] The amino acid derivative co-assembly agent provided by the present application contains guanidino, N-substituted guanidino or N-substituted urea groups, and when it is mixed with PACz molecules and assembled on the surface of a conductive oxide, the groups can form a hydrogen bond network with the PACz molecules due to the multiple hydrogen bond acceptor and donor atoms, fill the gaps between the PACz molecules by exerting the strong mutual bonding effect of multiple hydrogen bonds, significantly inhibit the excessive aggregation between the PACz molecules, reduce the large-size micelles and aggregates formed in the alcohol / water phase system, and further promote the uniform anchoring of the PACz molecules on the substrate, form a dense and uniform mixed self-assembled monolayer, improve the coverage on the interface, prevent the direct contact between the conductive oxide and the perovskite, and effectively improve the photoelectric conversion efficiency and stability of the device.

[0011] Moreover, compared with the phosphoric acid / phosphonic acid groups, the carboxylic acid groups of the amino acid derivative co-assembly agent provided by the present application have a relatively weak interaction with the oxide substrate such as ITO, and the adsorption strength is weak, which not only does not corrode the substrate and damage its stability, but also does not replace the phosphonic acid anchoring site of the PACz molecules during the deposition process, effectively avoids the disadvantage of a narrow competitive window of co-adsorbed molecules, and finally ensures the effective reactivity of the PACz molecules with the surface of the substrate.

[0012] In addition, the molecular dipole of the amino acid derivative co-assembly agent can affect the work function of the substrate at the interface, so that the semiconductor energy level alignment is more matched; the electronegative group (such as the nitrogen atom in the guanidino group or the urea group) in the molecule can act as a Lewis base and strongly coordinate with the uncoordinated Pb 2+ in the perovskite, effectively passivating cation defects; at the same time, the electropositive region (such as the protonated guanidino group or N-H bond) can be combined with halide ions (I - ) through electrostatic interaction, which helps to inhibit ion migration and reduce the formation of halogen vacancy defects.

[0013] Preferably, the molecule of the amino acid derivative co-assembly agent is 1-guanidino acetic acid (GAAc), N-methyl guanidino acetic acid (MeGAAc) or 2-ureido acetic acid (UrAc).

[0014] The amino acid derivative co-assembly agent provided by the present application has a functional group containing multiple hydrogen bond acceptor and donor atoms, which can form a hydrogen bond network with the PACz molecules, promote the uniform anchoring of the PACz molecules on the substrate, and at the same time has a weakly adsorbed carboxylic acid group with the conductive oxide substrate, so that when it is used to prepare a perovskite solar cell, the open-circuit voltage of the perovskite solar cell can be increased to 1.123-1.140 V, the fill factor can be increased to 83.2-84.0%, and the short-circuit current density can be increased to 26.0-26.3 mA / cm 2, the photoelectric conversion efficiency is improved to 24.33~25.43%, and the photoelectric performance and stability of the solar cell are comprehensively improved.

[0015] Further preferably, the amino acid derivative co-assembly agent is 1-guanidino acetic acid.

[0016] The amino acid derivative co-assembly agent 1-guanidino acetic acid provided by the application has stronger association of multiple hydrogen bonds with PACz molecules, is more conducive to inhibiting the formation of PACz micelles and random aggregation, has a larger dipole moment, and is helpful for passivation of defects and improvement of interface energy level matching.

[0017] In another aspect, the application also provides a mixed self-assembled monolayer, comprising: PACz molecules and the amino acid derivative co-assembly agent; Preferably, the PACz molecules are Me-4PACz, 2PACz or 4PABCz. The mass ratio of the PACz molecules to the amino acid derivative co-assembly agent is 1:0.5~1:1.

[0018] By controlling the mass ratio of the PACz molecules to the amino acid derivative co-assembly agent, the application can ensure that the two form sufficient molecular pairing through the association of multiple hydrogen bonds, and further avoid the aggregation of PACz molecules.

[0019] In another aspect, the application also provides a preparation method of the mixed self-assembled monolayer, comprising: First, the PACz molecules and the amino acid derivative co-assembly agent are dissolved in a polar solvent according to a mass ratio of 1:0.5~1:1, then coated on the surface of a substrate by a wet process, and heated and annealed to obtain the mixed self-assembled monolayer.

[0020] The preparation method of the mixed self-assembled monolayer provided by the application can fully exert the uniform anchoring effect of the mixed self-assembled monolayer on the substrate, does not damage the stability of the substrate, effectively inhibits interface defects and improves energy level regulation, and thus finally improves the photoelectric conversion performance and working stability of the device.

[0021] Preferably, the polar solvent is an alcohol solvent or an alcohol / water mixed solvent, which can promote the dissolution and stable existence of the PACz molecules and the amino acid derivative co-assembly agent.

[0022] Further preferably, the alcohol solvent is ethanol or isopropanol.

[0023] Preferably, the substrate is ITO glass or ITO glass on which a nickel oxide thin film or a SnO2 thin film is deposited, and the substrate is a conductive oxide substrate.

[0024] Preferably, the coating method is spin coating or blade coating.

[0025] Further preferably, the blade coating environment is a protective atmosphere or a dry environment, and the blade coating speed is 3-15 mm / s, which can make the PACz molecules and the amino acid derivative co-assembly agent uniformly spread on the surface of the conductive oxide substrate.

[0026] Preferably, the heating annealing temperature is 80-120℃, and the heating annealing time is 5-15 min, which can promote the ordered self-assembly of the PACz molecules on the conductive oxide substrate and volatilize excess solvent, forming a dense and uniform mixed self-assembly monolayer.

[0027] The preparation method provided by the present application has a simple process and can be easily integrated into existing large-area coating processes, which is of great significance for promoting the industrialization of high-efficiency and stable perovskite photovoltaic devices.

[0028] In another aspect, the present application also provides a perovskite solar cell, comprising: a conductive oxide electrode, a mixed self-assembly monolayer, a perovskite absorption layer, a passivation layer, an electron transport layer and a metal cathode which are sequentially stacked.

[0029] Since the PACz molecules in the mixed self-assembly monolayer can be preferentially anchored on the conductive oxide substrate through phosphonic acid groups, and are arranged closely and orderly, the coverage and uniformity of the self-assembly monolayer film formed are effectively improved. Therefore, by using the mixed self-assembly monolayer, the energy level gradient of the perovskite solar interface can be significantly optimized, and the amino acid derivative co-assembly agent in the mixed self-assembly monolayer can also play a passivation effect on the side facing the perovskite, realizing the multiple functions of "enhancing anchoring, improving film formation, defect passivation and energy level optimization", thereby significantly improving the photoelectric performance and stability of the perovskite solar cell.

[0030] Preferably, the electron transport layer is C 60 or PCBM, the passivation layer is PDAI2, and the metal cathode is Ag or an electrode network.

[0031] Compared with the prior art, the present application has the following beneficial effects: The guanidino group, N-substituted guanidino group or N-substituted urea group in the amino acid derivative co-assembly agent has multiple hydrogen bond acceptor and donor atoms, can form multiple hydrogen bonds with PACz molecules, realize strong binding, fill the gap between PACz molecules, inhibit excessive aggregation between PACz molecules, and the carboxyl group in the amino acid derivative co-assembly agent has a relatively weak interaction with the conductive oxide substrate, co-adsorbs instead of replacing the phosphonic acid anchoring site of the PACz molecule in the deposition process, can reduce the large-size micelles and aggregates formed by the PACz molecules from the source without damaging the stability of the substrate, and further form a dense and uniform mixed self-assembled monolayer, and the amino acid derivative co-assembly agent can also passivate perovskite film defects and improve energy level matching, realize the multiple functions of “enhanced anchoring, improved film formation, defect passivation and energy level optimization”, and significantly improve the photoelectric performance and stability of the perovskite battery. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The chemical structural formulas of the Me-4PACz molecules in the embodiments 1-3 of the present application and the amino acid derivative co-assembly agents 1-guanidino acetic acid, N-methyl guanidino acetic acid and 2-ureido acetic acid are shown in the figure; Figure 2 The schematic diagram of the pairing of Me-4PACz, 1-guanidino acetic acid, N-methyl guanidino acetic acid and 2-ureido acetic acid with Me-4PACz molecules in the comparative example 1 and the embodiments 1-3 of the present application is shown in the figure; Figure 3 (a) in the figure is the interface schematic diagram of the mixed self-assembled monolayer of the present application on the surface of the conductive oxide substrate ITO in the comparative example 1 of the present application; (b) is the interface schematic diagram of the mixed self-assembled monolayer of the present application on the surface of the conductive oxide substrate ITO in the embodiments 1-3 of the present application; Figure 4 The structure schematic diagram of the perovskite solar cell device prepared in the application example 1 of the present application is shown in the figure. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0034] The chemical structural formulas of the Me-4PACz molecules in the embodiments 1-3 of the present application and the amino acid derivative co-assembly agents 1-guanidino acetic acid, N-methyl guanidino acetic acid and 2-ureido acetic acid are shown in the figure; Figure 1 .

[0035] Example 1 Weigh 0.7 mg of Me-4PACz (solid, analytical grade) and 0.5 mg of the amino acid-derived co-assembly agent 1-guanidinoacetic acid (GAAc), add them to 1 mL of anhydrous ethanol, and gently shake or sonicate until clear to obtain a mixed solution. The mass ratio of Me-4PACz to GAAc is 1.4:1. The ITO-coated glass substrate is then sequentially washed with detergent, deionized water, and ethanol in an ultrasonic cleaner for 30 min, dried in a vacuum drying oven at 80 °C, and then subjected to UV ozone treatment for 20 min to obtain a pretreated ITO glass substrate. Next, in an inert atmosphere, 7 μL of the mixed solution is dropped onto the surface of the ITO glass substrate, and then sprayed at a speed of 6 mm·s. -1 The film was uniformly coated by linear speed, and then heated on a hot stage at 100℃ for 10 min, followed by cooling to room temperature to obtain a mixed self-assembled monolayer of ITO / Me-4PACz+GAAc.

[0036] Example 2 The only difference from Example 1 is that the amino acid-derived co-assembly agent in Example 2 is N-methylguanidinoacetic acid, which is used to prepare a mixed self-assembled monolayer of ITO / Me-4PACz+MeGAAc.

[0037] Example 3 The only difference from Example 1 is that the amino acid-derived co-assembly agent in Example 3 is 2-urea-acetic acid, which is used to prepare a mixed self-assembled monolayer of ITO / Me-4PACz+UrAc.

[0038] Schematic diagrams of the interfaces of the hybrid self-assembled monolayers on the surface of the conductive oxide substrate ITO in Examples 1-3 of this invention, as shown below. Figure 3 As shown in (b), it can be seen that the multiple hydrogen bonds formed between the amino acid-derived co-assembler and the Me-4PACz molecule can significantly inhibit the aggregation of Me-4PACz molecules on the substrate, and can form a dense and uniform co-assembled monolayer.

[0039] Comparative Example 1 The only difference from Example 1 is that Comparative Example 1 uses only Me-4PACz and does not mix it with an amino acid-derived co-assembly agent to prepare an ITO / Me-4PACz self-assembled monolayer.

[0040] A schematic diagram of the interface of the Me-4PACz self-assembled monolayer on the conductive oxide substrate ITO surface in Comparative Example 1 of this invention, as shown below. Figure 3 As shown in (a), it can be seen that Me-4PACz molecules form micelles and aggregates on the conductive oxide substrate ITO surface, resulting in uneven adsorption, obvious gaps, and inability to effectively anchor to the substrate.

[0041] Schematic diagrams of the pairing of Me-4PACz, 1-guanidinoacetic acid, N-methylguanidinoacetic acid, and 2-ureidoacetic acid with Me-4PACz molecules in Comparative Example 1 and Examples 1-3 of this invention, as shown below. Figure 2 As shown in the figure, the hydrogen bond length and molecular binding energy are labeled. It can be seen that the guanidinium and urea groups contained in the amino acid-derived co-assembler can form stable pairings with Me-4PACz molecules through multiple hydrogen bonds. Their binding energy is comparable to or greater than that of two Me-4PACz molecules, thereby regulating the aggregation state of Me-4PACz molecules.

[0042] Application Example 1 Fabrication of inverted perovskite solar cells: First, an appropriate amount of MACl was added to FAPbI3 according to a molar ratio of FAI:PbI2:MACl of 1.0:1.07:0.14, and then dissolved in a mixed solvent of DMF / DMSO / ACN to obtain a perovskite precursor solution. The precursor solution was then coated onto the ITO / Me-4PACz+GAAc mixed self-assembled monolayer prepared in Example 1 at a blade coating speed of 11 mm / s. All steps were performed inside a glove box. Subsequently, film formation and crystallization were accelerated using a dry air air knife, and finally annealed at 120°C for 15 minutes to obtain a uniform α-FAPbI3 perovskite film. Next, a layer of isopropanol / chlorobenzene solution of the interface passivator PDAI2 was coated onto the surface of the α-FAPbI3 perovskite film, followed by low-temperature annealing to form a passivation layer. Subsequently, C was sequentially deposited on the passivation layer by vacuum thermal evaporation. 60 (20 nm) and Bathocuproine (BCP, 5 nm) were used as electron transport / buffer layers, and finally a silver electrode with a thickness of 100 nm was deposited to prepare a 0.035 cm⁻¹ electrode. 2 (2×2 mm) 2 The perovskite solar cell with the inverted structure (with windows) described above.

[0043] A schematic diagram of the perovskite solar cell device fabricated in Application Example 1 of this invention is shown below. Figure 4 As shown.

[0044] Application Example 2 The only difference from Application Example 1 is that the hybrid self-assembled monolayer in Application Example 2 is the ITO / Me-4PACz+MeGAAc hybrid self-assembled monolayer prepared in Example 2.

[0045] Application Example 3 The only difference from Application Example 1 is that the hybrid self-assembled monolayer in Application Example 3 is the ITO / Me-4PACz+UrAc hybrid self-assembled monolayer prepared in Example 3.

[0046] Application Comparative Example 1 The only difference from Application Example 1 is that the self-assembled monolayer of Comparative Example 1 is the ITO / Me-4PACz self-assembled monolayer prepared in Comparative Example 1.

[0047] Performance Analysis The open-circuit voltages of the perovskite solar cells prepared in the above-described Application Examples 1-3 and Comparative Example 1 are... V OC Fill factor FF, short-circuit current density J SC The photoelectric conversion efficiency (PCE) is shown in Table 1.

[0048] Table 1. Open-circuit voltages of perovskite solar cells prepared in Application Examples 1-3 and Comparative Example 1 V OC Fill factor FF, short-circuit current density J SC and photoelectric conversion efficiency (PCE) As shown in Table 1, the hybrid self-assembled monolayer provided by this invention, due to the presence of guanidinyl and urea groups in the amino acid-derived co-assembler, which have multiple hydrogen bond acceptor and donor atoms, can form strong association with Me-4PACz molecules through multiple hydrogen bonds. This causes the micelles and large aggregates formed by Me-4PACz molecules to depolymerize. Moreover, compared with phosphonic acid groups, the carboxyl groups in the amino acid-derived co-assembler have a relatively weak interaction with the conductive oxide substrate and will not interfere with Me-4PACz molecules, allowing them to play a preferential anchoring role and form a dense and uniform hybrid self-assembled monolayer. This optimizes the energy level gradient at the device interface, improves the film quality and coverage of the perovskite film at this interface, and thus improves the open-circuit voltage, fill factor, short-circuit current density, and photoelectric conversion efficiency of the perovskite solar cell.

[0049] The present invention also conducted repeatability tests on the application examples 1-3. The results showed that the hybrid self-assembled monolayer provided by the present invention exhibited good reproducibility when used in the fabrication of perovskite solar cells, with an average open-circuit voltage increase of 30 mV and an average fill factor increase of 3 percentage points. This is attributed to improved interface energy level alignment and reduced non-radiative recombination losses. UPS testing of the perovskite solar cell prepared in application example 1 showed that the maximum valence band position of the ITO / Me-4PACz+GAAc substrate was significantly shifted upwards compared to ITO / Me-4PACz, reducing the gap between it and the perovskite valence band peak from 0.3 eV to 0.03 eV, and the interface hole extraction barrier approached zero. Furthermore, the electronegative functional groups (nitrogen atoms in guanidinyl and urea groups) introduced by the hybrid self-assembled monolayer can effectively passivate Pb on the perovskite surface. 2+ The defects were reduced, the interfacial recombination current was decreased, and the open-circuit voltage and fill factor of perovskite solar cells were synergistically improved.

[0050] Moreover, compared to the mixed self-assembled monolayers formed by MeGAAc and UrAc with Me-4PACz, the ITO / Me-4PACz+GAAc mixed self-assembled monolayer, due to the larger dipole moment of the GAAc molecule, can reduce the micelle size of the SAMs solution to a greater extent, which is conducive to the formation of a uniform and dense hole transport layer and the formation of optimal energy level arrangement, which is more conducive to hole transport.

[0051] This invention also conducted operational stability tests on the perovskite solar cells prepared in Application Example 1 and Comparative Example 1. The test method was as follows: Under an unencapsulated, inert atmosphere, the two groups of perovskite solar cells underwent a high-temperature accelerated aging comparative test, i.e., the perovskite solar cells were continuously placed in a nitrogen environment at 85°C, and their photoelectric performance was tested at regular intervals. The test results showed that the PCE of the perovskite solar cell prepared in Comparative Example 1 using an ITO / Me-4PACz self-assembled monolayer decreased to 50% of its initial value after 1000 hours, while the perovskite solar cell prepared in Application Example 1 using a mixed ITO / Me-4PACz+GAAc self-assembled monolayer still maintained 90.8% of its initial efficiency after operating at the same 85°C for 3048 hours. This indicates that even under long-term illumination, the efficiency of the perovskite solar cell provided by this invention remains stable. The introduction of the amino acid-derived co-assembly agent GAAc effectively suppressed interfacial degradation factors (such as the desorption and interfacial reaction of Me-4PACz), thereby significantly improving the thermal stability and long-term reliability of the perovskite / electrode interface.

Claims

1. An amino acid-derived co-assembly agent, characterized in that, The general chemical formula of the amino acid-derived co-assembly agent is R-CH2-COOH, where R is a guanidinyl, N-substituted guanidinyl, or N-substituted urea group.

2. The amino acid-derived co-assembly agent according to claim 1, characterized in that, The amino acid-derived co-assembly agent is 1-guanidinoacetic acid, N-methylguanidinoacetic acid, or 2-ureoacetic acid.

3. The amino acid-derived co-assembly agent according to claim 2, characterized in that, The amino acid-derived co-assembly agent is 1-guanidinoacetic acid.

4. A hybrid self-assembled monolayer, characterized in that, include: PACz-type molecules and amino acid-derived co-assemblies according to any one of claims 1-3; The PACz class molecules are Me-4PACz, 2PACz, or 4PABCz; The mass ratio of the PACz-type molecules to the amino acid-derived co-assembler is 1:0.5 to 1:

1.

5. A method for preparing a hybrid self-assembled monolayer according to claim 4, characterized in that, include: First, the PACz-type molecules and the amino acid-derived co-assembly agent according to any one of claims 1-3 are dissolved in a polar solvent at a mass ratio of 1:0.5 to 1:1; Then, a wet coating process is used to coat the substrate surface, followed by heating and annealing to obtain the hybrid self-assembled monolayer.

6. The method for preparing a hybrid self-assembled monolayer according to claim 5, characterized in that, The polar solvent is an alcohol solvent or an alcohol / water mixture solvent.

7. The method for preparing a hybrid self-assembled monolayer according to claim 5, characterized in that, The substrate is ITO glass or ITO glass with a nickel oxide film or SnO2 film deposited on it.

8. The method for preparing a hybrid self-assembled monolayer according to claim 5, characterized in that, The heating and annealing temperature is 80~120℃, and the heating and annealing time is 5~15 min.

9. A perovskite solar cell, characterized in that, include: The conductive oxide electrode, the hybrid self-assembled monolayer as described in claim 4, the perovskite absorption layer, the passivation layer, the electron transport layer, and the metal cathode are stacked sequentially.

10. The perovskite solar cell according to claim 9, characterized in that, The electron transport layer is C. 60 Alternatively, a PCBM may be used, wherein the passivation layer is PDAI2, and the metal cathode is Ag or an electrode network.

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