A buried base modification material for a flexible perovskite solar cell and a preparation method and application thereof

Abstract

The present application relates to the technical field of solar cells, in particular to a buried bottom modification material for flexible perovskite solar cells and a preparation method and application thereof, wherein polyacrylic acid and its derivatives and mercaptoethylamine or its analogues are used as main reaction raw materials, a buried bottom modification material containing mercapto is generated through cross-linking reaction, the buried bottom modification material is spin-coated on a hole transport layer to prepare a buried bottom interface layer, and a flexible perovskite solar cell containing the buried bottom interface layer is prepared based on the buried bottom interface layer. The present application uses the above-mentioned buried bottom modification material for flexible perovskite solar cells and a preparation method and application thereof, and uses the polymer containing mercapto as the buried bottom modification material in the transverse flexible perovskite solar cell, so that the efficiency and mechanical stability of the flexible perovskite solar cell are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a buried bottom modification material for a flexible perovskite solar cell and a preparation method and application thereof. BACKGROUND

[0002] With the continuous innovation of industrial technology, wearable smart devices and portable electronic products have developed rapidly, and the market demand for flexible solar cells is increasing day by day. Metal halide perovskite cells have the advantages of low-temperature processing, thin light-absorbing layer, and lightweight design, and have more advantages in the preparation of flexible solar cells. At present, the development of flexible perovskite solar cells is very rapid, and the efficiency has increased from 2.62% in 2013 to 25.09% in 2024. The efficiency of a flexible photovoltaic module with a size of 36.50cm 2 has reached 18.71%.

[0003] During service, flexible perovskite solar cells will inevitably be subjected to stress such as stretching, shearing and bending, which may cause cracking of the perovskite film and interface peeling. The water and oxygen isolation ability of the flexible perovskite substrate is poor, which makes the perovskite light-absorbing layer prone to phase transition and decomposition. In addition, the flexible substrate is usually not resistant to high temperature, and there are a large number of defects in the perovskite film prepared at low temperature, which reduces the photoelectric efficiency and mechanical stability of the flexible perovskite solar cell. One of the methods to improve the photoelectric efficiency of the flexible perovskite solar cell is to passivate the defects in the perovskite and the interface. Chen Wei's research group (2024, Nature) proposed a buried bottom interface self-assembly monolayer hybrid strategy, which induced Me-4PACz molecules to be more uniformly distributed, and the presence of polycarboxylate NA monomers effectively improved the wettability of the perovskite solution on Me-4PACz, eliminated the nanopores at the buried bottom interface, enhanced the crystallinity of the perovskite buried bottom interface, and reduced the defect concentration at the buried bottom interface, thereby obtaining a high-efficiency perovskite solar cell. Zhang Weifeng's research group (2024, Advanced Materials) used two novel donor-acceptor type semiconducting covalent organic frameworks (COFs) as modification materials for the buried interface of trans perovskite solar cells. These COFs effectively regulated the morphology and defects of the buried interface film, and matched the energy levels of the perovskite film, thereby improving the extraction and transport of interface charges. Tan Zhankao's research group (2023, Advanced Materials) designed an amphoteric organic salt, 2-(4-fluorophenyl) ethylammonium-4-methylbenzenesulfonate (4FPEAPSA), to optimize the film morphology and energy level arrangement of the perovskite buried interface, passivate iodine and formamidinium vacancy defects, and restore the Fermi energy level of the perovskite to a defect-free state.

[0004] The above methods effectively improve the photoelectric efficiency and stability of the perovskite solar cell, but the hole transport material, nickel oxide, commonly used in the transverse perovskite solar cell is an inorganic material, which is inherently brittle. In addition, the interface bonding force between the hole transport layer and the perovskite layer is not strong enough, which can easily lead to interface cracking, thereby reducing the service life of the transverse flexible perovskite solar cell during service, hindering the industrialization development of the flexible perovskite solar cell. SUMMARY

[0005] The purpose of the present application is to provide a buried bottom modification material for a flexible perovskite solar cell and its preparation method and application. By introducing a thiol-containing polymer buried bottom modification material, the defects of the buried bottom interface are passivated, and the interface bonding force between the hole transport layer and the perovskite layer is enhanced, thereby improving the efficiency and mechanical stability of the transverse flexible perovskite solar cell.

[0006] To achieve the above-mentioned purpose, the present application provides a buried bottom modification material for a flexible perovskite solar cell, which is prepared by cross-linking reaction of polyacrylic acid and its derivatives and mercaptoethylamine or its analogues as the main reaction raw materials to generate a thiol-containing polymer buried bottom modification material.

[0007] Preferably, the polyacrylic acid and its derivatives are one of polyacrylic acid, polymethyl acrylic acid, sodium polyacrylate, and potassium polyacrylate.

[0008] Preferably, the mercaptoethylamine or its analogues are one of mercaptoethylamine, mercaptopropylamine, and mercaptobutylamine.

[0009] The above-mentioned preparation method of the buried bottom modification material for a flexible perovskite solar cell comprises the following steps:

[0010] S1, dissolving polyacrylic acid and its derivatives in solvent one to prepare a reaction solution one;

[0011] S2, dissolving mercaptoethylamine or its analogues in solvent two to prepare a reaction solution two;

[0012] S3, using a dropper to add the reaction solution two of S2 dropwise to the reaction solution one of S1, washing the reaction product with an alcohol solution after the reaction is complete, and then vacuum drying and storing the reaction product in a nitrogen environment to obtain a thiol-containing polymer buried bottom modification material.

[0013] Preferably, the solvent one in S1 is one of water, methanol, ethanol, propanol, or a mixed solution of methanol-water, and the concentration of the reaction solution one is 25-40 mg / mL.

[0014] Preferably, the solvent two in S2 is one of water, methanol, ethanol, and isopropanol, and the concentration of the reaction solution two is 10-20 wt%.

[0015] Preferably, the alcohol solution in S3 is a methanol solution.

[0016] The application of the buried bottom modification material for the flexible perovskite solar cell is applied to the preparation of the flexible perovskite solar cell, and comprises the following steps,

[0017] T1, pretreatment of the flexible substrate;

[0018] T2, preparation of a hole transport layer on the flexible substrate in T1;

[0019] T3, preparation of a buried bottom interface layer on the hole transport layer in T2;

[0020] T4, preparation of a perovskite layer on the buried bottom interface layer in T3;

[0021] T5, deposition of an electron transport layer on the perovskite layer in T4;

[0022] T6, deposition of a metal electrode on the electron transport layer in T5.

[0023] Preferably, the flexible substrate in T1 is polyethylene naphthalate / indium tin oxide or polyethylene terephthalate / indium tin oxide.

[0024] Preferably, the material of the hole transport layer in T2 is nickel oxide, PEDOT:PSS, PTAA or a SAM monolayer.

[0025] Preferably, the preparation method of the buried bottom interface layer in T3 is that the buried bottom modification material is dissolved in deionized water to obtain a buried bottom modification material solution, the buried bottom modification material solution is spin-coated on the wet film of the hole transport layer, the spin-coating speed is 1500-5000 rpm, the spin-coating time is 15-40 s, after spin-coating, annealing is carried out at 100-150 DEG C for 10-30 min, and the concentration of the buried bottom modification material solution is 0.01-5 mg / mL.

[0026] Preferably, the perovskite layer in T4 is APbX3 structure, wherein A is one or a mixture of methylamine, formamidinium and cesium ion, and X is one or a mixture of I, Br and Cl.

[0027] Preferably, the metal electrode in T6 is one of gold, silver and copper, and the thickness of the metal electrode is 50-300 nm.

[0028] The mechanism of the application is as follows:

[0029] The buried bottom modification material provided by the application can be -COO - , -NH 3+The electrostatic interaction and hydrogen bond formation between the -COOH and -SH functional groups form a firm 3D cross-linked network, which can be used as a buffer layer between the hole transport layer and the perovskite film to reduce the interlayer stress of the flexible perovskite solar cell; the C=O in the polymer can reduce the defects on the surface of the oxide and improve the mechanical toughness of the hole transport layer through chemical coordination. The -SH in the polymer can form a stable chemical bond with the lead ions suspended on the surface of the perovskite, thereby reducing the defect state density of the perovskite surface and passivating the defects of the perovskite film. The buried interface modification material containing the mercapto group can passivate the interface defects and improve the interface strength, so that the high-efficiency and stable flexible perovskite solar cell is obtained.

[0030] The beneficial effects of the present application are as follows:

[0031] (1) The preparation method of the buried interface modification material for the flexible perovskite solar cell is simple, the raw materials are low in price and easy to obtain, and the experiment is highly repeatable, which meets the requirements of low-temperature preparation of the flexible perovskite solar cell;

[0032] (2) The buried interface modification material for the flexible perovskite solar cell is constructed into a 3D cross-linked network through hydrogen bond and electrostatic interaction, and the introduction of the 3D cross-linked network as a buffer layer between the hole transport layer and the perovskite film can reduce the Young's modulus of the hole transport layer and the perovskite film and enhance the interlayer bonding force;

[0033] (3) The buried interface modification material for the flexible perovskite solar cell can passivate defects through the synergistic effect of the carboxyl group and the mercapto group at the end, improve the quality of the hole transport layer and the perovskite film, and further improve the photoelectric performance and mechanical durability of the flexible perovskite solar cell.

[0034] The technical solutions of the present application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a structure schematic diagram of the flexible perovskite solar cell with buried interface reverse transposition according to the present application;

[0036] Figure 2 It is a comparison diagram of the Young's modulus of the nickel oxide hole transport layer obtained by testing example 2 and comparative example 1 according to the present application;

[0037] Figure 3 It is a comparison diagram of the cross-sectional morphology of the perovskite layer of the perovskite solar cell prepared by example 2 and comparative example 1 according to the present application;

[0038] Figure 4 It is a comparison diagram of the Young's modulus of the perovskite film prepared by example 2 and comparative example 1 according to the present application;

[0039] Figure 5A comparison chart of mechanical bending stability test results of flexible perovskite solar cells prepared for the present embodiment 2 and the comparative example 1;

[0040] Figure 6 A comparison chart of J-V curves of flexible perovskite solar cells prepared for the present embodiment 2 and the comparative example 1;

[0041] Figure 7 A J-V curve chart of the flexible perovskite solar cell prepared for the present embodiment 3;

[0042] Figure 8 A J-V curve chart of the flexible perovskite solar cell prepared for the present embodiment 4. DETAILED DESCRIPTION

[0043] The present application will be further described below in conjunction with the accompanying drawings and embodiments. Unless otherwise defined, the technical terms or scientific terms used in the present application shall be understood as the usual meanings understood by those skilled in the art to which the present application belongs. The features mentioned in the present application or the features mentioned in the specific examples can be combined in any manner, and these specific examples are only used to illustrate the present application and not to limit the scope of the present application.

[0044] Embodiment 1

[0045] The present application provides a buried bottom modification material for a flexible perovskite solar cell, which is prepared from polyacrylic acid (PAA) and mercaptoethylamine (MEA) as reaction raw materials, and a polymer mercaptoethylamine polyacrylic acid salt (PAA-MEA) is generated by reaction. The preparation method specifically includes the following steps:

[0046] S1, preparation of a polyacrylic acid solution

[0047] 1.09g of PAA was added to a round-bottom flask containing 30mL of methanol solvent, and stirred with a magnetic stirrer until completely dissolved to obtain a polyacrylic acid solution;

[0048] S2, preparation of a mercaptoethylamine solution

[0049] The mercaptoethylamine was dissolved in the methanol solvent to prepare a 10mL mercaptoethylamine solution with a concentration of 11wt%;

[0050] S3, the mercaptoethylamine solution of S2 was slowly added to the polyacrylic acid solution of S1 with a dropper, and after the reaction was complete, the crude product was collected by filtering with filter paper, the crude product was washed with methanol solution for 3 times, and the washed product was placed in a vacuum drying cabinet and vacuum dried at 50℃ for 12h to obtain PAA-MEA polymer material as a buried bottom modification material. The dried solid PAA-MEA polymer was packed in a small bottle and placed in a nitrogen glove box for storage.

[0051] Embodiment 2

[0052] Figure 1 The structure diagram of the buried bottom interface reverse type flexible perovskite solar cell structure of the present application is shown in the figure. Figure 1 The present application provides a buried bottom modification material for a flexible perovskite solar cell for preparing a flexible perovskite solar cell, which comprises the following steps:

[0053] T1, pretreatment of the flexible substrate

[0054] T1.1, PET / ITO is selected as the flexible substrate, which is cut into a size of 1.5 cm x 1.5 cm with a paper cutter according to the etching line, and is sequentially ultrasonically cleaned with deionized water, detergent, and ethanol, and after cleaning, the flexible substrate is placed in a drying cabinet and dried at 70°C for 1 h;

[0055] T1.2, the glass slide is cut into a size of 1.5 cm x 1.5 cm, the high-temperature-resistant double-sided tape is pasted around, the dried flexible substrate is pasted on the cut glass slide, and ultraviolet-ozone treatment is performed for 15 min, followed by plasma cleaning for 60 s for standby.

[0056] T2, preparation of a hole transport layer on the flexible substrate of T1

[0057] T2.1, 15 mg of nickel oxide is weighed into 1 mL of deionized water, and ultrasonic treatment is performed in an ultrasonic machine for 40 min to obtain a nickel oxide dispersion solution with a concentration of 15 mg / mL;

[0058] T2.2, the nickel oxide dispersion solution is spin-coated on the treated flexible substrate of T1, the spin-coating speed is 3000 rpm, the spin-coating time is 25 s, and after spin-coating, no annealing is performed to obtain a wet film of the hole transport layer.

[0059] T3, preparation of a buried bottom interface layer on the hole transport layer of T2

[0060] T3.1, 2 mg of PAA-MEA product is weighed into 20 mL of deionized water to form a uniform solution, a PAA-MEA solution with a concentration of 0.1 mg / mL is obtained, and ultrasonic treatment is performed in an ultrasonic machine for 20 min;

[0061] T3.2, the PAA-MEA solution is spin-coated on the unannealed wet film of the hole transport layer, the spin-coating speed is 5000 rpm, the spin-coating time is 30 s, and after spin-coating, annealing is performed at 100°C for 20 min to obtain the nickel oxide hole transport layer treated with the buried bottom interface layer, and then it is placed in a nitrogen glove box for standby.

[0062] T4, preparation of a perovskite layer on the buried bottom interface layer of T3

[0063] T4.1, Cs0.05 FA 0.85 MA 0.1 PbI3 as the light-absorbing material of the perovskite layer, the light-absorbing material is dissolved in a solvent to prepare a perovskite solution with a concentration of 1.5 mol / mL, and the solvent is a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in a volume ratio of 4:1;

[0064] T4.2 The perovskite solution is spin-coated on the buried interface layer by multi-step spin coating. The first step is spin coating at a spin speed of 1000 rpm for 10 s, and the second step is spin coating at a spin speed of 5000 rpm for 30 s. At the 12th second of the second step, anti-solvent chlorobenzene (CB) is added dropwise. After spin coating, annealing is performed at 100°C for 50 min to form a perovskite layer.

[0065] T5, depositing an electron transport layer on the perovskite layer of T4

[0066] Vacuum evaporation of electron transport layer C60 and BCP on the perovskite layer, the substrate with the perovskite layer prepared in T4 is placed in the evaporation mask, and the chamber pressure is 10 -4 pa, C60 evaporation is started, the thickness of the C60 layer is 25 nm, then when the chamber temperature drops below 260°C, BCP evaporation is started, and the thickness of the BCP layer is 5 nm.

[0067] T6, depositing a metal electrode on the electron transport layer of T5

[0068] The substrate with the electron transport layer deposited in T5 is placed in the mask, the silver boat is installed, 2 silver particles are placed, the hatch is closed, the material parameters are set, the evaporation rate is 0.01 nm / s, the final thickness is set to 120 nm, coarse pumping is performed first, then fine pumping is performed when the pressure drops to below 5 pa, and then pre-evaporation can be started when the pressure drops to 10 -4 pa, after the rate is stable, formal evaporation is started, and after evaporation is completed, the substrate is taken out and stored in a nitrogen glove box to obtain a transverse flexible perovskite solar cell with a buried interface layer.

[0069] Example 3

[0070] Based on Example 2, the difference between Example 2 and Example 3 is that the concentration of the PAA-MEA solution in T3.1 is 0.01 mg / mL.

[0071] Example 4

[0072] Based on Example 2, the difference between Example 2 and Example 4 is that the concentration of the PAA-MEA solution in T3.1 is 1 mg / mL.

[0073] Comparative Example 1

[0074] The difference from Example 2 is that step T3 was not performed, i.e., no buried interface layer was prepared. Instead, nickel oxide dispersion was spin-coated onto the flexible substrate to obtain a nickel oxide hole transport layer without a buried interface layer, thereby obtaining a flexible perovskite solar cell without a buried interface layer.

[0075] Performance testing

[0076] The nickel oxide hole transport layer after the buried interface layer treatment prepared in Example 2 and the nickel oxide hole transport layer without the buried interface layer prepared in Comparative Example 1 were subjected to nanoindentation tests, and the results are as follows: Figure 2 As shown, the Young's modulus of Example 2 is significantly lower than that of Comparative Example 1, which means that the nickel oxide hole transport layer modified by the PAA-MEA buried interface is more flexible and malleable, and the film is less prone to cracking or breaking under stress.

[0077] The perovskite layers of the flexible perovskite solar cells prepared in Example 2 and Comparative Example 1 were analyzed by cross-sectional scanning electron microscopy (SEM), and their morphologies are as follows: Figure 3 As shown, the perovskite grains in Example 2 are more orderly and of higher quality. The orderly arrangement of grains can reduce defects at grain boundaries, reduce the probability of non-radiative recombination, and thus improve the photoelectric performance of perovskite solar cells.

[0078] The perovskite layers of the flexible perovskite solar cells prepared in Example 2 and Comparative Example 1 were subjected to nanoindentation tests, and the results are as follows: Figure 4 As shown, the Young's modulus of Example 2 is significantly lower than that of Comparative Example 1. The reduction in Young's modulus increases the reliability and stability of the perovskite solar cell during its service life.

[0079] The flexible perovskite solar cells prepared in Example 2 and Comparative Example 1 were subjected to a 3 mm mechanical bending test. The efficiency of the cells was recorded every 1000 bends. The results are as follows: Figure 5 As shown, the buried interface treatment method provided by the present invention can improve the mechanical stability of flexible perovskite solar cells.

[0080] The flexible perovskite solar cells prepared in Example 2 and Comparative Example 1 were respectively tested at AM 1.5G, 100mW cm⁻¹. -2 Photoelectric performance was tested under illumination conditions, and the test results are as follows: Figure 6 As shown, the efficiency of Comparative Example 1 is 19.08%, and the efficiency of Example 2 is 22.05%, indicating that the buried interface treatment method provided by the present invention can improve the efficiency of flexible perovskite solar cells.

[0081] The flexible perovskite solar cells prepared in Example 3 were tested at AM 1.5G and 100mW cm⁻¹.-2 The photoelectric performance test was carried out under the light condition of AM 1.5G, 100mW cm Figure 7 The test result is shown in Figure 6, and the obtained efficiency is 19.68%.

[0082] The flexible perovskite solar cell prepared in Example 4 was subjected to photoelectric performance test under the light condition of AM 1.5G, 100mW cm -2 The test result is shown in Figure 6, and the obtained efficiency is 19.68%. Figure 8 The test result is shown in Figure 6, and the obtained efficiency is 19.68%.

[0083] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced by equivalents, and these modifications or replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. An application of a buried modification material for flexible perovskite solar cells, characterized in that: The buried substrate modification material is generated by cross-linking a polymer containing thiol groups through a reaction using polyacrylic acid and its derivatives with mercaptoethylamine or its analogues as the main reactants. This material is then used in the fabrication of flexible perovskite solar cells, and includes the following steps: T1. Pretreatment of flexible substrate; T2. A hole transport layer is prepared on the flexible substrate of T1; T3. Prepare a buried interface layer on the hole transport layer of T2; T4. Prepare a perovskite layer on the buried interface layer of T3; T5. Deposit an electron transport layer on the perovskite layer of T4; T6. Deposit a metal electrode on the electron transport layer of T5; The hole transport layer in T2 is made of nickel oxide, PEDOT:PSS, PTAA or SAM monolayer. The preparation method of the buried interface layer in T3 is as follows: the buried modification material is dissolved in deionized water to obtain a buried modification material solution, the buried modification material solution is spin-coated onto the hole transport layer wet film at a spin-coating speed of 1500~5000 rpm and a spin-coating time of 15~40s, and then annealed at 100~150℃ for 10 min~30 min. The concentration of the buried modification material solution is 0.01~5mg / mL. Polyacrylic acid and its derivatives are one of polyacrylic acid, polymethacrylic acid, sodium polyacrylate, and potassium polyacrylate; Mercaptoethylamine or its analogues are one of mercaptoethylamine, mercaptopropylamine, and mercaptobutylamine.

2. The application of the buried modification material for flexible perovskite solar cells according to claim 1, characterized in that: The flexible substrate in T1 is either polyethylene naphthalate / indium tin oxide or polyethylene terephthalate / indium tin oxide.

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