Self-repairing hydrophobic buried-bottom interface layer based on dynamic covalent bonds and preparation method and application of self-repairing hydrophobic buried-bottom interface layer

Abstract

The invention discloses a self-repairing hydrophobic bottom-buried interface layer based on a dynamic covalent bond and a preparation method and application thereof, and the method comprises the steps: preparing the bottom-buried interface layer through a simple solution spin-coating method based on a self-healing strategy of a dynamic reversible bond, greatly relieving the sensitivity of a flexible perovskite solar cell to bottom water oxygen permeation, and improving the reliability of the flexible perovskite solar cell. A firm hydrophobic barrier is constructed in the device; meanwhile, the interface layer interacts with a perovskite precursor, and a perovskite thin film which is high in crystallization quality, large in grain size, excellent in orientation and low in defect density is formed through guidance. Based on the synergistic effect, not only can the flexible perovskite solar cell with the conversion efficiency exceeding 26% be prepared, but also the long-term stability of the device in a harsh humidity environment is remarkably improved. In addition, the buried interface layer effectively releases the interface stress in the bending process of the device, so that the obtained flexible device has excellent mechanical bending stability and waterproof capability.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic materials and devices technology, specifically relating to a self-healing hydrophobic buried interface layer based on dynamic covalent bonds, its preparation method, and its application. Background Technology

[0002] Flexible perovskite solar cells, due to their lightweight and bendable properties, have shown great potential in portable electronics and building-integrated photovoltaics (BIPV). However, their commercialization is severely hampered by stability issues, particularly long-term moisture resistance. This stems primarily from two factors: flexible plastic substrates (such as PI, PET, and PEN) have high water vapor permeability, allowing moisture to easily penetrate from the bottom and cause perovskite material decomposition. Additionally, the surface roughness and chemical inhomogeneity of flexible substrates result in poor crystallinity of the perovskite film, leading to numerous defects that affect device efficiency and stability. This significantly hinders the commercialization of flexible perovskite solar cells.

[0003] Currently used encapsulation methods, such as top hydrophobic layers or independent encapsulation films, are difficult to effectively block water and oxygen from penetrating from the substrate side. If a hydrophobic layer is placed as a "buried interface" below the perovskite layer, it can block water vapor at the bottom, but it faces the problem of incompatibility with polar perovskite precursor solutions: traditional hydrophobic layers need to be treated with plasma or ultraviolet-ozone to improve wettability, but such treatments will permanently destroy their hydrophobic structure and lose their long-term water-blocking function.

[0004] Therefore, developing a buried interface material that can serve as a bottom water and oxygen barrier layer, be compatible with perovskite preparation processes, and even actively improve the crystallization quality of perovskite is key to promoting the development of flexible perovskite solar cells. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a self-healing hydrophobic buried interface layer based on dynamic covalent bonds, its preparation method, and its application.

[0008] To solve the above technical problems, the present invention provides the following technical solution: a method for preparing a self-healing hydrophobic buried interface layer based on dynamic covalent bonds, characterized in that: it includes dissolving a polymer / monomer capable of forming dynamic covalent bonds, a crosslinking agent and SiO2 nanoparticles in a solvent to form a precursor solution, then spin-coating it onto a SnO2 electron transport layer, and then heat-treating it to form the dynamic crosslinking network;

[0009] Among them, dynamic covalent bonds include one or more of the following: dynamic imine bond, acylhydrazone, Diels-Alder reaction bond, reversible disulfide bond, borate ester bond, urea bond, acetal / ketal bond;

[0010] The chemical structural formula is as follows:

[0011]

[0012] Where R is an alkyl chain, cycloalkane group, or heterocyclic substituent, and the chemical structure is as follows:

[0013]

[0014]

[0015] Crosslinking agents include one of tetrahydrofuran, a water-ethanol mixed solvent, and N,N-dimethylformamide;

[0016] Among them, dynamic imine bonds are formed by the reaction of amino-containing polymers and aldehyde compounds through Schiff base reactions; acylhydrazone bonds are formed by the condensation reaction of acylhydrazine groups and aldehyde compounds; Diels-Alder reaction bonds are formed by the reversible cycloaddition reaction of compounds containing furan groups and maleimide groups; reversible disulfide bonds are formed by compounds containing thiol groups under oxidative conditions; and borate ester bonds are formed by the coordination of compounds containing boric acid groups and ortho-diol groups.

[0017] The chemical structural formulas containing aldehyde substituents are selected from:

[0018] The chemical structural formulas containing amino substituents are selected from:

[0019]

[0020] In a preferred embodiment of the preparation method described in this invention, the concentration of the polymer / monomer with dynamic covalent bonds is 0.5–5.0 mmol / mL, and the amount of SiO2 nanoparticles added is 10%–30%.

[0021] In a preferred embodiment of the preparation method described in this invention, the heat treatment temperature is 80–100 °C and the treatment time is 10–30 min.

[0022] Another objective of this invention is to overcome the shortcomings of the prior art and provide a self-healing hydrophobic buried interface layer based on dynamic covalent bonds prepared by a preparation method.

[0023] Another objective of this invention is to overcome the shortcomings of the prior art and provide a flexible perovskite solar cell based on a dynamic bond self-healing hydrophobic buried interface, comprising a flexible conductive substrate, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer and a metal electrode, wherein a dynamic bond self-healing hydrophobic interface layer is disposed between the electron transport layer and the perovskite light-absorbing layer.

[0024] A method for fabricating a flexible perovskite solar cell based on a dynamic bond self-healing hydrophobic buried interface: an electron transport layer is prepared on a flexible conductive substrate; then the dynamic bond self-healing hydrophobic interface layer is spin-coated onto the electron transport layer; then surface treatment is performed, a perovskite precursor solution is deposited on the treated interface layer and heat-treated to form a perovskite thin film layer; then a hole transport layer and an anode are sequentially prepared on the perovskite thin film.

[0025] As a preferred embodiment of the preparation method described in this invention, the surface treatment includes one of plasma treatment, ultraviolet-ozone treatment, or ozone treatment.

[0026] In a preferred embodiment of the preparation method described in this invention, the processing time is 1 to 10 minutes.

[0027] In a preferred embodiment of the preparation method described in this invention, the processing time is 3 to 5 minutes.

[0028] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of a self-healing hydrophobic buried interface layer based on dynamic covalent bonds in the process of regulating perovskite crystallization. The feature is that the electron-rich groups in the self-healing hydrophobic buried interface layer based on dynamic covalent bonds can coordinate with PbI2, guiding PbI2 to form a vertically oriented mesoporous structure, promoting the full penetration and reaction of organic ammonium salts, and obtaining a perovskite film with high crystal quality, excellent crystal orientation, and low defect density.

[0029] Beneficial effects of this invention:

[0030] (1) This invention introduces a dynamic bond self-healing hydrophobic interface layer between the electron transport layer and the perovskite light-absorbing layer, thereby achieving a synergistic improvement in the efficiency, stability and mechanical durability of flexible perovskite solar cells.

[0031] (2) The dynamic bond self-healing hydrophobic interface layer designed in this invention has a unique self-healing hydrophobic mechanism, which not only ensures good compatibility with perovskite solution process, but also establishes a long-term stable moisture barrier, effectively solving the technical problem of incompatibility between traditional hydrophobic layer and perovskite preparation process.

[0032] (3) The present invention utilizes the coordination between the functional groups in the interface layer and the perovskite precursor to guide the perovskite to form a preferred oriented crystal structure, which significantly improves the crystal quality and photoelectric properties of the perovskite film.

[0033] (4) The interface layer preparation process of the present invention is simple and has good process compatibility with large-area flexible substrates. Its self-healing properties can effectively compensate for interface defects in the large-area preparation process, providing a reliable technical solution for the industrial manufacturing of high-performance large-area flexible perovskite solar cells.

[0034] (5) The dynamic bond self-healing hydrophobic interface layer of the present invention has universality and is applicable to a variety of perovskite component systems and different thin film deposition processes, showing broad application prospects. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0036] Figure 1 The FTIR spectrum of the dynamic imine bond self-healing hydrophobic interface layer in an embodiment of the present invention is shown.

[0037] Figure 2 This is a graph showing the change of water contact angle over time during the self-healing process of the interface layer in an embodiment of the present invention.

[0038] Figure 3 These are cross-sectional and planar SEM images of the PbI2 film before and after interface layer modification in an embodiment of the present invention.

[0039] Figure 4 These are cross-sectional and planar SEM images of the perovskite film before and after interface layer modification in an embodiment of the present invention.

[0040] Figure 5 The following are GIWAXS spectra of perovskite films before and after interface layer modification in an embodiment of the present invention;

[0041] Figure 6 This is a current-voltage curve of a flexible perovskite solar cell with a self-healing hydrophobic interface according to an embodiment of the present invention.

[0042] Figure 7 The figures show the current-voltage curves of flexible perovskite solar cells with different concentrations of dynamic imine bond self-healing hydrophobic interface layers in embodiments of the present invention.

[0043] Figure 8 The following are current-voltage curves of flexible perovskite solar cells with different types of dynamic imine bond self-healing hydrophobic interface layers in embodiments of the present invention.

[0044] Figure 9 This is a current-voltage curve of a flexible perovskite solar cell with a self-healing hydrophobic interface introduced based on different perovskite systems, according to an embodiment of the present invention.

[0045] Figure 10 The images show the steady-state fluorescence spectra of the flexible perovskite thin film before and after modification in an embodiment of the present invention.

[0046] Figure 11 This is a beam-induced current mapping diagram of the flexible perovskite thin film before and after modification in an embodiment of the present invention;

[0047] Figure 12 This is a diagram showing the current-voltage curves of a large-area flexible perovskite solar cell before and after modification, according to an embodiment of the present invention.

[0048] Figure 13 The results of water vapor transmission rate tests on the flexible substrate before and after modification in this embodiment of the invention;

[0049] Figure 14 This is a diagram showing the change in the interface contact angle after plasma treatment in an embodiment of the present invention.

[0050] Figure 15 These are SEM images of the perovskite film before and after interface layer modification in an embodiment of the present invention, taken under humidity aging.

[0051] Figure 16 The images show the steady-state photoluminescence spectra of the perovskite films before and after interface layer modification in an embodiment of the present invention under humidity aging.

[0052] Figure 17 This is a humidity stability diagram of flexible perovskite solar cells before and after interface layer modification in an embodiment of the present invention;

[0053] Figure 18 The figures show the IPX7 waterproof performance of flexible perovskite solar cells before and after interface layer modification in an embodiment of the present invention.

[0054] Figure 19 This is a diagram showing the bending stability of flexible perovskite solar cells before and after interface layer modification in an embodiment of the present invention. Detailed Implementation

[0055] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0056] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0057] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0058] Unless otherwise specified, all raw materials used in the embodiments of this invention are commercially available.

[0059] PET / ITO is used as a flexible conductive substrate and requires routine cleaning before use.

[0060] The device's photoelectric performance was simulated using a Newport xenon lamp at AM 1.5G under a solar irradiance of 100 mW / cm². 2 Under these conditions, light intensity was obtained using a source meter (Keithley 2400) and calibrated using a standard silicon cell with a KG-5 filter. Steady-state power conversion efficiency was calculated by measuring the stable photocurrent density at a constant bias voltage (Vmax point), with the effective area of ​​the device corrected using precisely calibrated apertures (0.062 and 1.004 cm²). 2 ).

[0061] Example 1

[0062] A method for preparing a dynamically imine-linked self-healing hydrophobic interface layer (SHC) includes the following steps: 1.0 g of amino-terminated polydimethylsiloxane (NH2-PDMS-NH2, number-average molecular weight 2000 g / mol, 0.3 g) and 0.3 g of 1,3,5-benzenetriformaldehyde are dissolved in tetrahydrofuran (20 mL) at a 1:1 molar ratio of amino to aldehyde groups. SiO2 nanoparticles (0.26 g, particle size 7 nm) are added, and the mixture is stirred at room temperature for 6 hours to form a prepolymer solution. This solution is then spin-coated onto a PET / ITO / SnO2 substrate at 3000 rpm and heat-treated at 80 °C for 30 minutes to form a dynamically imine-linked hydrophobic interface layer (SHC) with a thickness of approximately 25 nm. Figure 1 FTIR of a hydrophobic interface layer crosslinked with imine bonds.

[0063] Example 2

[0064] A method for preparing a dynamically cross-linked self-healing hydrophobic interface layer (BSHC) formed by borate ester coordination includes the following steps: Polyvinyl alcohol (PVA, 99% degree of hydrolysis, 1.0 g, 22.7 mmol structural units) and boric acid (0.42 g, 3.4 mmol) are added to a 50 mL round-bottom flask at a molar ratio of ortho-hydroxyl to boric acid group of 2:1. Then, a water-ethanol mixed solvent (volume ratio 1:1, 20 mL) and SiO2 nanoparticles (0.28 g, particle size 7 nm) are added. After stirring at room temperature for 6 hours, the resulting uniform prepolymer solution is spin-coated onto a SnO2 electron transport layer at 3000 rpm, and heat-treated at 80 °C for 30 minutes to form a dynamically cross-linked hydrophobic interface layer (BSHC) formed by borate ester coordination.

[0065] Example 3

[0066] A method for preparing a dynamically cross-linked self-healing hydrophobic interface layer (HSHC) formed by acylhydrazone condensation reaction includes the following steps: Benzoyl hydrazide (1.0 g, 7.3 mmol) and benzaldehyde (0.78 g, 7.3 mmol) are added to a 50 mL round-bottom flask at a molar ratio of acyl hydrazone to aldehyde group of 1:1. The flask is evacuated and rinsed three times with dry nitrogen gas, then purified ethanol solvent (15 mL) is added, followed by SiO2 nanoparticles (0.36 g, particle size 7 nm, mass of 20% of the total mass of reactants). The mixture is stirred continuously at room temperature for 8 hours to form a homogeneous and stable prepolymer solution through acylhydrazone condensation reaction. This solution is spin-coated onto a pretreated SnO2 electron transport layer at 3500 rpm, followed by heat treatment at 80 °C for 30 minutes to form an HSHC self-healing hydrophobic interface layer with a thickness of approximately 20 nm.

[0067] Example 4

[0068] A method for preparing a dynamic imine bond self-healing hydrophobic interface layer on a flexible conductive substrate includes the following steps:

[0069] (1) First, prepare the SHC precursor solution: Dissolve NH2-PDMS-NH2 (1.0 g) and 1,3,5-benzenetriformaldehyde (0.3 g) in tetrahydrofuran at a molar ratio of amino to aldehyde of 1:1, add SiO2 nanoparticles (0.2 g, particle size 7 nm), stir at room temperature for 2 hours to form a uniform dispersion, and then dilute the precursor solution to 3 mg / mL.

[0070] (3) The cleaned PET / ITO substrate was surface-treated with plasma for 5 min to temporarily make it hydrophilic. The diluted solution was spin-coated onto the pre-treated substrate at 3500 rpm, followed by heat treatment at 80 °C for 30 min to form a hydrophobic interface layer with a thickness of about 20 nm. Due to the self-healing properties of the interface, such as Figure 2 The subsequent interface shown will restore the hydrophobic effect.

[0071] Example 5

[0072] A method for preparing a perovskite thin film based on a dynamic imine bond self-healing hydrophobic interface layer on a flexible conductive substrate includes the following steps:

[0073] (1) First, prepare the SHC precursor solution: Dissolve NH2-PDMS-NH2 (1.0 g) and 1,3,5-benzenetriformaldehyde (0.3 g) in tetrahydrofuran at a molar ratio of amino to aldehyde of 1:1, add SiO2 nanoparticles (0.2 g, particle size 7 nm), stir at room temperature for 2 hours to form a uniform dispersion, and then dilute the precursor solution to 3 mg / mL.

[0074] (2) A SnO2 electron transport layer was spin-coated on a clean PET / ITO substrate using a tin dioxide dispersion (12% aqueous solution) at a spin speed of 3000 rpm and annealed at 130 ℃ for 30 min.

[0075] (3) The interface layer was treated with plasma for 5 min to temporarily make it hydrophilic. The diluted solution was spin-coated onto the pretreated SnO2 electron transport layer at 3500 rpm, and then heat-treated at 80°C for 30 min to form a hydrophobic interface layer with a thickness of about 20 nm.

[0076] (4) Spin-coating the prepared PbI2 solution onto the interface, annealing to obtain a lead iodide-doped film at 1500 rpm and 70 °C for 1 min. Figure 3 The image shows cross-sectional SEM images of the doped and undoped lead iodide films. The doped lead iodide film exhibits a sparse and porous morphology.

[0077] (5) Next, spin-coat the dried PbI2 film with FAI isopropanol solution; then anneal at 150 °C for 15 min to obtain a perovskite film. Figure 4 The image shown is a SEM image of the surface morphology of the aforementioned flexible perovskite film. It can be seen from the image that the perovskite film with the hydrophobic interface exhibits enhanced compactness, larger grains, and less lead iodide. Figure 5The image shown is a GIWAXS diagram of the aforementioned flexible perovskite thin film. The GIWAXS indicates an improved orientation of the (100) crystal plane. Therefore, this invention solves the problem of poor growth of perovskite thin films on flexible substrates.

[0078] Example 6

[0079] A flexible perovskite solar cell (effective area 0.062 cm²) 2 The preparation method of ) includes the following steps:

[0080] (1) First, PbI2 (692 mg / mL) was dissolved in N,N-dimethylformamide (DMF) solvent to form PbI2DMF solution; at the same time, FAI (90 mg / mL) was dissolved in isopropanol solvent to prepare FAI isopropanol solution.

[0081] (2) In a clean 1.5×1.5 cm 2 A layer of SnO2 was spin-coated onto a flexible conductive substrate using a tin dioxide dispersion (12% aqueous colloid). The spin-coating speed was 3000 rpm, and the substrate was annealed at 130 °C for 30 min.

[0082] (3) A two-step method was used to prepare the perovskite layer. The prepared PbI2 solution was spin-coated onto SnO2 and annealed to obtain a lead iodide film at 1500 rpm and 70 °C for 1 min. Then, FAI isopropanol solution was spin-coated onto the dried PbI2 film. Finally, the film was annealed on a hot plate at 150 °C for 15 min to obtain the perovskite film.

[0083] (4) Spiro-OMeTAD was prepared as a hole transport layer on a perovskite film. The solvent was chlorobenzene with a concentration of 72.3 mg / mL, and the spin coating speed was 2000 rpm.

[0084] (5) The thin film was placed in a vacuum coating machine to deposit gold electrodes with a thickness of 100 nm, resulting in an effective area of ​​0.062 cm². 2 Flexible perovskite solar cells without hydrophobic interfaces.

[0085] Example 7

[0086] A flexible perovskite solar cell based on a dynamic imine bond self-healing hydrophobic interface layer (effective area 0.062 cm²) 2 The preparation method of ) includes the following steps:

[0087] (1) First, prepare the SHC precursor solution: Dissolve NH2-PDMS-NH2 (1.0 g) and 1,3,5-benzenetriformaldehyde (0.3 g) in tetrahydrofuran at a molar ratio of amino to aldehyde of 1:1, add SiO2 nanoparticles (0.2 g, particle size 7 nm), stir at room temperature for 2 hours to form a uniform dispersion, and then dilute the precursor solution to 3 mg / mL;

[0088] (2) First, PbI2 (692 mg / mL) was dissolved in N,N-dimethylformamide (DMF) solvent to form PbI2 DMF solution; at the same time, FAI (90 mg / mL) was dissolved in isopropanol solvent to prepare FAI isopropanol solution.

[0089] (3) In a clean 1.5×1.5 cm 2 A layer of SnO2 was spin-coated onto a flexible conductive substrate using a tin dioxide dispersion (12% aqueous colloid). The spin-coating speed was 3000 rpm, and the substrate was annealed at 130 °C for 30 min.

[0090] (4) The interface layer is surface-treated with plasma for 5 minutes to temporarily impart hydrophilicity. Due to the self-healing properties of the interface, such as... Figure 2 The interface shown will regain its hydrophobic effect. The diluted solution was spin-coated onto the pretreated SnO2 electron transport layer at 3500 rpm, and then heat-treated at 80°C for 30 minutes to form a hydrophobic interface layer with a thickness of about 20 nm.

[0091] (5) A two-step method was used to prepare the perovskite layer. The prepared PbI2 solution was spin-coated onto the interface and annealed to obtain a lead iodide film. The spin speed was 1500 rpm and the annealing temperature was 70 °C for 1 min. Then, FAI isopropanol solution was spin-coated onto the dried PbI2 film. Finally, the film was annealed on a hot plate at 150 °C for 15 min to obtain the perovskite film.

[0092] (6) Spiro-OMeTAD was prepared as a hole transport layer on a perovskite film. The solvent was chlorobenzene with a concentration of 72.3 mg / mL, and the spin coating speed was 2000 rpm.

[0093] (7) The thin film was placed in a vacuum coating machine to deposit gold electrodes with a thickness of 100 nm, resulting in an effective area of ​​0.062 cm². 2 Flexible perovskite solar cells based on dynamic imine bond self-healing hydrophobic interface layers.

[0094] Comparing the performance of the perovskite solar cells in Examples 5 and 6, we obtain Figure 6 (Current-voltage curve of perovskite solar cell (effective area 0.062 cm²)) 2According to Table 1, the light intensity is AM1.5G 100 mW / cm². 2 .

[0095] Table 1 Comparison of photovoltaic performance parameters of perovskite solar cells

[0096]

[0097] from Figure 6 As shown in Table 1, the photoelectric performance of flexible perovskite solar cells is significantly improved after modifying the electron transport layer with the dynamic self-healing hydrophobic interface layer (SHC) described in this invention. Specifically, the open-circuit voltage (VOC) reaches 1.19 V, the fill factor (FF) increases to 84.87%, and a final photoelectric conversion efficiency of 26.38% (effective area 0.062 cm²) is achieved. The results indicate that by introducing the dynamic self-healing hydrophobic interface layer, the crystallization process of the perovskite film on the flexible substrate can be effectively controlled, resulting in perovskite films with high crystal quality, uniform grain size, and low defect state density. This interface modification strategy significantly promotes the interfacial transport process of charge carriers and effectively suppresses non-radiative recombination losses.

[0098] Example 8

[0099] A method for fabricating a flexible perovskite solar cell based on a self-healing hydrophobic interface layer with different concentrations of dynamic imine bonds includes the following steps:

[0100] (1) First, prepare the SHC precursor solution: Dissolve NH2-PDMS-NH2 (1.0 g) and 1,3,5-benzenetriformaldehyde (0.3 g) in tetrahydrofuran at a molar ratio of amino to aldehyde of 1:1, add SiO2 nanoparticles (0.2 g, particle size 7 nm), stir at room temperature for 2 hours to form a uniform dispersion, and then dilute the precursor solution to 1 mg / mL, 3 mg / mL and 5 mg / mL respectively;

[0101] (2) PbI2 (692 mg / mL) was dissolved in N,N-dimethylformamide (DMF) solvent to form PbI2 DMF solution; at the same time, FAI (90 mg / mL) was dissolved in isopropanol solvent to prepare FAI isopropanol solution.

[0102] (3) In a clean 1.5×1.5 cm 2 A layer of SnO2 was spin-coated onto a flexible conductive substrate using a tin dioxide dispersion (12% aqueous colloid). The spin-coating speed was 3000 rpm, and the substrate was annealed at 130 °C for 30 min.

[0103] (4) The interface layer was subjected to plasma surface treatment for 5 min to temporarily make it hydrophilic. The diluted solution was spin-coated onto the pretreated SnO2 electron transport layer at 3500 rpm, and then heat-treated at 80℃ for 30 min to form a hydrophobic interface layer with a thickness of about 20 nm.

[0104] (5) A two-step method was used to prepare the perovskite layer. The prepared PbI2 solution was spin-coated onto the interface and annealed to obtain a lead iodide film. The spin speed was 1500 rpm and the annealing temperature was 70 °C for 1 min. Then, FAI isopropanol solution was spin-coated onto the dried PbI2 film. Finally, the film was annealed on a hot plate at 150 °C for 15 min to obtain the perovskite film.

[0105] (6) Spiro-OMeTAD was prepared as a hole transport layer on a perovskite film. The solvent was chlorobenzene with a concentration of 72.3 mg / mL, and the spin coating speed was 2000 rpm.

[0106] (7) The thin film was placed in a vacuum coating machine to deposit gold electrodes with a thickness of 100 nm, resulting in an effective area of ​​0.062 cm². 2 Flexible perovskite solar cells based on self-healing hydrophobic interface layers with different concentrations of dynamic imine bonds.

[0107] Current-voltage curves of flexible perovskite solar cells with self-healing hydrophobic interface layers of different concentrations of dynamic imine bonds are shown below. Figure 7 According to Table 2, the light intensity is AM1.5G 100 mW / cm². 2 The method for preparing a blank flexible perovskite solar cell is described in Example 6.

[0108] Table 2 Comparison of photovoltaic performance parameters of flexible perovskite solar cells

[0109]

[0110] Modification with an SHC interface layer significantly improved the photoelectric conversion efficiency of flexible perovskite solar cells, mainly through a synergistic enhancement of open-circuit voltage and fill factor. The results show that at an SHC concentration of 3 mg / mL, the device achieved an open-circuit voltage of 1.19 V and a fill factor of 84.87%, ultimately achieving a photoelectric conversion efficiency of 26.38%. This superior performance is attributed to the multiple functions of the SHC interface layer: firstly, its dynamic imine bond crosslinking network coordinates with PbI2, guiding the formation of a vertically oriented mesoporous PbI2 scaffold structure; secondly, the introduction of SiO2 nanoparticles enhances the mechanical strength and superhydrophobic properties of the interface layer; and most importantly, the SHC interface layer effectively regulates the crystallization process of perovskite on the flexible substrate, promoting the formation of high-quality perovskite films, significantly reducing the interface defect state density, thereby improving carrier transport efficiency and suppressing non-radiative recombination losses.

[0111] Example 9

[0112] A method for fabricating flexible perovskite solar cells based on self-healing hydrophobic interface layers with different types of dynamic bonds includes the following steps:

[0113] (1) First, prepare the SHC precursor solution: Dissolve NH2-PDMS-NH2 (1.0 g) and 1,3,5-benzenetriformaldehyde (0.3 g) in tetrahydrofuran at a molar ratio of amino to aldehyde of 1:1. Add SiO2 nanoparticles (0.2 g, particle size 7 nm), stir at room temperature for 2 hours to form a uniform dispersion, and then dilute the precursor solution to 3 mg / mL. For other dynamic bond hydrophobic interfaces, see Examples 2 and 3. Prepare precursor solutions according to the same strategy and dilute them to 3 mg / mL respectively.

[0114] (2) PbI2 (692 mg / mL) was dissolved in N,N-dimethylformamide (DMF) solvent to form PbI2 DMF solution; at the same time, FAI (90 mg / mL) was dissolved in isopropanol solvent to prepare FAI isopropanol solution.

[0115] (3) In a clean 1.5×1.5 cm 2 A layer of SnO2 was spin-coated onto a flexible conductive substrate using a tin dioxide dispersion (12% aqueous colloid). The spin-coating speed was 3000 rpm, and the substrate was annealed at 130 °C for 30 min.

[0116] (4) The interface layer was subjected to plasma surface treatment for 5 min to temporarily make it hydrophilic. The diluted solution was spin-coated onto the pretreated SnO2 electron transport layer at 3500 rpm, and then heat-treated at 80℃ for 30 min to form a hydrophobic interface layer with a thickness of about 20 nm.

[0117] (5) A two-step method was used to prepare the perovskite layer. The prepared PbI2 solution was spin-coated onto the interface and annealed to obtain a lead iodide film. The spin speed was 1500 rpm and the annealing temperature was 70 °C for 1 min. Then, FAI isopropanol solution was spin-coated onto the dried PbI2 film. Finally, the film was annealed on a hot plate at 150 °C for 15 min to obtain the perovskite film.

[0118] (6) Spiro-OMeTAD was prepared as a hole transport layer on a perovskite film. The solvent was chlorobenzene with a concentration of 72.3 mg / mL, and the spin coating speed was 2000 rpm.

[0119] (7) The thin film was placed in a vacuum coating machine to deposit gold electrodes with a thickness of 100 nm, resulting in an effective area of ​​0.062 cm². 2 Flexible perovskite solar cells based on self-healing hydrophobic interface layers with different types of dynamic imine bonds.

[0120] Current-voltage curves of flexible perovskite solar cells with different types of dynamic imine bond self-healing hydrophobic interface layers are shown below. Figure 8 According to Table 3, the light intensity is AM1.5G 100 mW / cm². 2 The method for preparing a blank flexible perovskite solar cell is described in Example 6.

[0121] Table 3 Comparison of photovoltaic performance parameters of flexible perovskite solar cells

[0122]

[0123] Example 10

[0124] A method for fabricating flexible perovskite solar cells based on a dynamic imine bond self-healing hydrophobic interface layer includes the following steps:

[0125] (1) First, prepare the SHC precursor solution: Dissolve NH2-PDMS-NH2 (1.0 g) and 1,3,5-benzenetriformaldehyde (0.3 g) in tetrahydrofuran at a molar ratio of amino to aldehyde of 1:1, add SiO2 nanoparticles (0.2 g, particle size 7 nm), stir at room temperature for 2 hours to form a uniform dispersion, and then dilute the precursor solution to 3 mg / ml;

[0126] (2) Prepare a PbI2 DMF solution (PbI2 concentration is 692 mg / mL) and a FAI isopropanol solution (concentration is 90 mg / mL); Prepare 20.8 mg CsI, 804 mg PbI2, 247.64 mg FAI, 10.8 mg MACl and 12.67 mg MAI dissolved in 1 mL of a mixed solvent of DMF and DMSO (volume ratio 9:1);

[0127] (3) In a clean 1.5×1.5 cm 2 A layer of SnO2 was spin-coated onto a flexible conductive substrate using a tin dioxide dispersion (12% aqueous colloid). The spin-coating speed was 3000 rpm, and the substrate was annealed at 130 °C for 30 min.

[0128] (4) The interface layer was subjected to plasma treatment for 5 min to temporarily make it hydrophilic. The diluted solution was spin-coated onto the pretreated SnO2 electron transport layer at 3500 rpm, and then heat-treated at 80°C for 30 min to form a hydrophobic interface layer with a thickness of about 20 nm.

[0129] (5) A two-step method was used to prepare the perovskite layer. The prepared PbI2 solution was spin-coated onto the interface and annealed to obtain a lead iodide film. The spin speed was 1500 rpm and the annealing temperature was 70 °C for 1 min. Then, FAI isopropanol solution was spin-coated onto the dried PbI2 film. Finally, the film was annealed on a hot plate at 150 °C for 15 min to obtain the perovskite film.

[0130] (6) The perovskite layer was prepared by a one-step method. The prepared precursor solution was spin-coated at 4000 rpm for 45 seconds on the interface. 10 seconds before the end of spin-coating, 200 μL of chlorobenzene was added as an anti-solvent. Then, the perovskite film was formed by annealing on a hot plate at 100°C for 30 min.

[0131] (6) Spiro-OMeTAD was prepared as a hole transport layer on a perovskite film. The solvent was chlorobenzene with a concentration of 72.3 mg / mL, and the spin coating speed was 2000 rpm.

[0132] (7) The thin film was placed in a vacuum coating machine to deposit gold electrodes with a thickness of 100 nm, resulting in an effective area of ​​0.062 cm². 2 Different flexible perovskite solar cells based on dynamic imine bond self-healing hydrophobic interface layers.

[0133] The performance of the above flexible perovskite solar cells is shown in [link to performance data]. Figure 9 According to Table 4, the light intensity is AM1.5G 100 mW / cm². 2 .

[0134] Table 4 Comparison of photovoltaic performance parameters of flexible perovskite solar cells

[0135]

[0136] Even in different perovskite systems and perovskite preparation methods, the modified electron transport layer using a dynamic self-healing hydrophobic interface layer can significantly improve the photovoltaic performance of flexible devices, proving that the present invention has good universality.

[0137] Example 11

[0138] A method for fabricating a large-area flexible perovskite solar cell based on a dynamic imine bond self-healing hydrophobic interface layer includes the following steps:

[0139] (1) First, prepare the SHC precursor solution: Dissolve NH2-PDMS-NH2 (1.0 g) and 1,3,5-benzenetriformaldehyde (0.3 g) in tetrahydrofuran at a molar ratio of amino to aldehyde of 1:1, add SiO2 nanoparticles (0.2 g, particle size 7 nm), stir at room temperature for 2 hours to form a uniform dispersion, and then dilute the precursor solution to 3 mg / mL.

[0140] (2) PbI2 (692 mg / mL) was dissolved in N,N-dimethylformamide (DMF) solvent to form PbI2 DMF solution; at the same time, FAI (90 mg / mL) was dissolved in isopropanol solvent to prepare FAI isopropanol solution.

[0141] (3) In a clean 2×2 cm 2 A layer of SnO2 was spin-coated onto a flexible conductive substrate using a tin dioxide dispersion (12% aqueous colloid). The spin-coating speed was 3000 rpm, and the substrate was annealed at 130 °C for 30 min.

[0142] (4) The interface layer was subjected to plasma treatment for 5 min to temporarily make it hydrophilic. The diluted solution was spin-coated onto the pretreated SnO2 electron transport layer at 3500 rpm, and then heat-treated at 80 °C for 30 min to form a hydrophobic interface layer with a thickness of about 20 nm.

[0143] (5) A two-step method was used to prepare the perovskite layer. The prepared PbI2 solution was spin-coated onto the interface and annealed to obtain a lead iodide film. The spin speed was 1500 rpm and the annealing temperature was 70 °C for 1 min. Then, FAI isopropanol solution was spin-coated onto the dried PbI2 film. Finally, the film was annealed on a hot plate at 150 °C for 15 min to obtain the perovskite film.

[0144] (6) Spiro-OMeTAD was prepared as a hole transport layer on a perovskite film. The solvent was chlorobenzene with a concentration of 72.3 mg / mL, and the spin coating speed was 2000 rpm.

[0145] (7) The thin film was placed in a vacuum deposition machine to deposit gold electrodes with a thickness of 100 nm, resulting in an effective area of ​​1.004 cm². 2 Flexible perovskite solar cells based on self-healing hydrophobic interface layers with different types of dynamic imine bonds.

[0146] See Figure 10 , Figure 11 The figure shows the steady-state fluorescence spectrum of the flexible perovskite film and the beam-induced current mapping of the flexible perovskite solar cell. As can be seen from the figure, even on a large-area flexible conductive substrate, the composition, morphology and photoelectric properties of the perovskite film are highly uniform.

[0147] The performance of the above flexible perovskite solar cells was tested using standard methods, and the results were obtained. Figure 12 The image shows the current-voltage curve of a flexible perovskite solar cell (effective area 1.004 cm²). 2 (See Table 5) and the light intensity is AM1.5G 100 mW / cm². 2 .

[0148] Table 5 Effective area 1.004 cm² 2 Photovoltaic performance of flexible perovskite solar cells

[0149]

[0150] from Figure 12 As shown in Table 5, during the fabrication of large-area flexible perovskite solar cells, the use of the dynamic self-healing hydrophobic interface layer described in this invention to modify the electron transport layer significantly improved key parameters such as the open-circuit voltage and fill factor, ultimately achieving a photoelectric conversion efficiency of 24.80% (effective area 1.004 cm²). The study demonstrates that by introducing a dynamic self-healing hydrophobic interface layer, not only can the crystallization process of the perovskite film on the flexible substrate be effectively controlled, but the dependence of perovskite growth on substrate area can also be significantly reduced. This interface engineering enables the production of perovskite films with high crystal quality, smooth and uniform surfaces, and low defect state density on larger flexible substrates, effectively promoting carrier interfacial transport and suppressing non-radiative recombination losses. Particularly noteworthy is the excellent process compatibility of the interface strategy in large-area devices; its self-healing properties and hydrophobic performance remain highly consistent within an effective area of ​​1.004 cm², fully demonstrating the unique advantages of the dynamic self-healing hydrophobic interface layer in advancing the large-area application of flexible perovskite solar cells.

[0151] Water-blocking properties of conductive flexible substrates. The method for preparing a dynamic imine bond self-healing hydrophobic interface layer on a flexible conductive substrate is described in Example 4.

[0152] Water vapor transmission rate was measured on the SHC-modified conductive flexible substrate, and the results were obtained. Figure 13 As shown in the figure, the water vapor transmission rate of the unmodified PET / ITO substrate was 10.2 g / m² / day, while the water vapor transmission rate of the SHC-modified substrate was significantly reduced to 1.72 × 10⁻⁶ g / m² / day. -3g / m² / day. This result indicates that the dynamically self-healing hydrophobic interface layer forms a dense water-blocking barrier on the surface of the flexible substrate. Furthermore, the SHC samples that self-heal after plasma treatment still maintain high hydrophobicity. Figure 14 This demonstrates that its self-healing properties can effectively maintain the stability of its water-blocking function.

[0153] Water-blocking properties of perovskite thin films. A method for fabricating a self-healing hydrophobic interface layer based on dynamic imine bonds on a flexible conductive substrate is described in Example 5.

[0154] The SHC-modified perovskite film was subjected to aging tests at 85% relative humidity. Figure 15 As shown, SEM observation of the film morphology evolution revealed that the unmodified perovskite film exhibited significant pinholes and grain boundary corrosion after 12 hours of aging, while the SHC-modified perovskite film maintained an intact surface morphology under the same conditions, indicating a significant improvement in moisture resistance. Simultaneously, PL spectroscopy (…) Figure 16 The fluorescence intensity changes of perovskite films during damp heat aging were monitored. The fluorescence intensity of the unmodified film decayed rapidly, while the fluorescence intensity of the SHC-modified film remained stable for 21 days, further confirming the effective protective effect of the SHC interface layer on the perovskite film.

[0155] Environmental stability tests were conducted on SHC-modified flexible perovskite solar cells. For example... Figure 17 As shown, the unmodified flexible device can only maintain 33.31% of its initial efficiency under 85% relative humidity, while the SHC-modified device still maintains 81.18% of its initial efficiency after 1000 hours under the same conditions. Other types of flexible perovskite solar cells with dynamic bond self-healing hydrophobic interface layers were tested under 85% relative humidity, and the results are summarized in Table 6 below.

[0156] Table 6

[0157]

[0158] This indicates that even in self-healing hydrophobic interface layer systems constructed with different types of dynamic chemical bonds, the photovoltaic performance and stability of flexible perovskite solar cells are significantly improved, fully demonstrating the universality and wide applicability of this strategy.

[0159] SHC-modified devices fully meet the IPX7 waterproof standard. Figure 18 After being immersed in 1 meter of water for 30 minutes, the material retained more than 95% of its initial properties. This result demonstrates that the dynamic self-healing hydrophobic interface layer not only effectively blocks water vapor penetration, but its self-healing properties also maintain the integrity of its protective function under harsh environments.

[0160] Moisture-resistant mechanical properties of perovskite solar cells. SHC-modified flexible perovskite solar cells were tested under conditions of 65% relative humidity and a bending radius of 5 mm. Figure 19 As shown, the efficiency of the unmodified flexible device can only be maintained at 26.15% of the initial efficiency after 10,000 bending cycles, while the SHC-modified flexible device can still maintain 90.35% of the initial efficiency under the same conditions. This significant difference indicates that the dynamic self-healing hydrophobic interface layer not only provides excellent moisture protection, but its unique dynamic cross-linked network structure also endows the flexible perovskite solar cell with excellent mechanical flexibility.

[0161] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A method for preparing a self-healing hydrophobic buried interface layer based on dynamic covalent bonds, characterized in that: include, Polymers / monomers capable of forming dynamic covalent bonds, crosslinking agents, and SiO2 nanoparticles are dissolved in a solvent to form a precursor solution, which is then spin-coated onto a SnO2 electron transport layer and heat-treated to form a dynamic crosslinked network. The dynamic covalent bonds include one or more of the following: dynamic imine bonds, acylhydrazones, Diels-Alder reaction bonds, reversible disulfide bonds, borate ester bonds, urea bonds, and acetal / ketal bonds; the crosslinking agents include one of the following: tetrahydrofuran, water-ethanol mixed solvent, and N,N-dimethylformamide. Among them, dynamic imine bonds are formed by the reaction of amino-containing polymers and aldehyde compounds through Schiff base reactions; acylhydrazone bonds are formed by the condensation reaction of acylhydrazine groups and aldehyde compounds; Diels-Alder reaction bonds are formed by the reversible cycloaddition reaction of compounds containing furan groups and maleimide groups; reversible disulfide bonds are formed by compounds containing thiol groups under oxidative conditions; and borate ester bonds are formed by the coordination of compounds containing boric acid groups and ortho-diol groups.

2. The preparation method according to claim 1, characterized in that: The concentration of the polymer / monomer with the dynamic covalent bond is 0.5–5.0 mmol / mL, and the amount of SiO2 nanoparticles added is 10%–30%.

3. The preparation method according to claim 1, characterized in that: The heat treatment temperature is 80–100 °C, and the treatment time is 10–30 min.

4. The self-healing hydrophobic buried interface layer based on dynamic covalent bonds prepared by the preparation method described in claims 1 to 3.

5. A flexible perovskite solar cell based on a dynamic bond self-healing hydrophobic buried interface, characterized in that: It includes a flexible conductive substrate, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode, wherein a dynamic bond self-healing hydrophobic interface layer as described in claim 4 is disposed between the electron transport layer and the perovskite light-absorbing layer.

6. The method for fabricating a flexible perovskite solar cell as described in claim 5, characterized in that: The method includes: preparing an electron transport layer on a flexible conductive substrate; then spin-coating the dynamic bond self-healing hydrophobic interface layer of claim 4 onto the electron transport layer; then surface treating the interface layer, depositing a perovskite precursor solution on the treated interface layer and heat-treating it to form a perovskite thin film layer; and then sequentially preparing a hole transport layer and an anode on the perovskite thin film.

7. The preparation method according to claim 6, characterized in that: The surface treatment includes one of plasma treatment, ultraviolet-ozone treatment, or ozone treatment.

8. The preparation method according to claim 7, characterized in that: The processing time is 1 to 10 minutes.

9. The preparation method according to claim 8, characterized in that: The processing time is 3 to 5 minutes.

10. The application of the self-healing hydrophobic buried interface layer based on dynamic covalent bonds as described in claim 4 in regulating the perovskite crystallization process, characterized in that: The electron-rich groups in the self-healing hydrophobic buried interface layer based on dynamic covalent bonds can coordinate with PbI2, guiding PbI2 to form a vertically oriented mesoporous structure, promoting the full penetration and reaction of organic ammonium salts, and obtaining perovskite films with high crystal quality, excellent crystal orientation and low defect density.

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