Preparation method of self-assembled monomolecular layer based on dip-coating process, solar cell and preparation method of solar cell

Abstract

The invention discloses a preparation method of a self-assembled monomolecular layer based on a dip-coating process, a solar cell and a preparation method thereof, and relates to the technical field of solar cells. Comprising the following steps: providing a first dispersion liquid comprising a first solvent and a self-assembled monomolecular layer material containing at least one alkoxy at the end position; the first solvent is a first alcohol organic solvent or a mixture of the first alcohol organic solvent and water; immersing a substrate into the first dispersion liquid, standing and soaking for a first preset time, then taking out the substrate, carrying out first annealing, immersing the substrate into a second alcohol organic solvent for a second preset time, then taking out the substrate, and carrying out second annealing to obtain a self-assembled monomolecular layer; the first preset time is greater than 0 min and less than or equal to 5 min. According to the dip-coating process provided by the invention, a high-quality self-assembled monomolecular layer can be quickly formed in a production window shorter than 5 minutes, the dip-coating process can be expanded to manufacture large-area and flexible devices, and the authentication efficiency of a corresponding solar cell reaches 27.23%.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to a method for preparing a self-assembled monolayer based on a dip-coating process, a solar cell, and the same method. Background Technology

[0002] Over the past decade, solar cells, such as perovskite solar cells, have become a core research direction in next-generation photovoltaics due to their excellent photoelectric properties, rapidly improving energy conversion efficiency, and ease of recycling. Among many key technologies, the use of self-assembled monolayers as interfacial hole-selective layers has proven to be an important strategy for promoting the development of high-performance perovskite solar cells. Hole-selective layers based on self-assembled monolayers, with their ultrathin molecular-level structure, not only maintain excellent carrier selectivity but also effectively reduce internal series resistance, thereby improving the overall performance of the device.

[0003] While spin coating, a widely adopted process, can rapidly form high-quality self-assembled monolayers, it still faces significant challenges in large-scale industrial production and flexible device fabrication. These challenges primarily include stringent requirements for substrate area and flatness, as well as low solution utilization efficiency, limiting the technology's scalability and adaptability to different device structures. In contrast, dip coating, with its high material utilization, reproducible batch production capabilities, and ability to ensure more thorough contact between phosphate groups and the conductive oxide substrate surface, is theoretically more suitable for large-area industrial production and flexible substrate processing. However, current dip coating processes still suffer from two key drawbacks: the processing time (typically requiring several hours of immersion) is much longer than spin coating, and the resulting (perovskite) solar cells have lower energy conversion efficiency. These issues collectively restrict its large-scale commercial application.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing a self-assembled monolayer based on dip coating process, a solar cell and the same method, which aims to solve the problems that the dip coating process used in the preparation of self-assembled monolayers is time-consuming and the corresponding solar cells have low energy conversion efficiency.

[0006] The technical solution of the present invention is as follows:

[0007] A first aspect of the present invention provides a method for preparing a self-assembled monolayer based on a dip-coating process, comprising the following steps:

[0008] A first dispersion is provided, the first dispersion comprising a first solvent and a self-assembled monolayer material; the first solvent is a first alcohol-based organic solvent, or the first solvent is a mixture of a first alcohol-based organic solvent and water; the self-assembled monolayer material contains at least one alkoxy group at its terminal position;

[0009] The substrate is immersed in the first dispersion, left to stand for a first preset time, then removed and subjected to a first annealing. It is then immersed in a second alcohol-based organic solvent for a second preset time, then removed and subjected to a second annealing to obtain the self-assembled monolayer. The first preset time is greater than 0 min and less than or equal to 5 min.

[0010] Optionally, the first solvent consists of a first alcohol-based organic solvent and water comprising 0 vol% to 6.0 vol% of the volume fraction of the first alcohol-based organic solvent.

[0011] Optionally, the first alcoholic organic solvent includes at least one of methanol, ethanol, isopropanol, and n-propanol.

[0012] Optionally, the method for preparing the first dispersion includes the following steps:

[0013] The self-assembled monolayer material is mixed with the first solvent, ultrasonicated for 10–20 min, and then stirred at 50–60 °C for 20–24 h to obtain the first dispersion.

[0014] Optionally, the second alcoholic organic solvent includes at least one selected from isopropanol, ethanol, and n-propanol; and / or,

[0015] The second preset time is 0.4 to 0.5 minutes.

[0016] Optionally, the temperature of the first annealing is 110–120°C, and the time of the first annealing is 15–20 min; and / or,

[0017] The temperature of the second annealing is 110-120℃, and the time of the second annealing is 10-20 minutes.

[0018] Optionally, the substrate is a rigid substrate or a flexible substrate;

[0019] The rigid substrate includes a glass substrate and a transparent conductive oxide layer located on the surface of the glass substrate;

[0020] The flexible substrate includes a polymer substrate and a transparent conductive oxide layer located on the surface of the polymer substrate.

[0021] Optionally, the general chemical structural formula of the self-assembled monolayer material is: L can be a conjugated linker or a non-conjugated linker;

[0022] The electron donor is selected from

[0023]

[0024]

[0025]

[0026] One of them;

[0027] in, Indicates the connection site, R1-R 14 Each of the following is independently derived from one of the following groups: hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidine, hydrazine, hydrazone, C1-C60 alkyl, C2-C60 alkenyl, C2-C60 alkoxy, C3-C60 cycloalkyl, C1-C10 heterocyclic alkyl, C3-C10 cycloalkenyl, C1-C10 heterocyclic alkenyl, C6-C60 aryl, C1-C60 heteroaryl, monovalent non-aromatic condensed polycyclic, monovalent non-aromatic condensed heteropolycyclic, biphenyl, and terphenyl, and R1-R 14 At least one of them is a C1-C60 alkoxy group.

[0028] In a second aspect, the present invention provides a solar cell, wherein the solar cell comprises a substrate, a self-assembled monomolecule, a light-absorbing layer, an electron transport layer and a top electrode stacked sequentially, wherein the self-assembled monomolecule is prepared by the preparation method of the present invention as described above.

[0029] A third aspect of the present invention provides a method for preparing a solar cell, comprising the following steps:

[0030] Provide substrate;

[0031] Using the preparation method of the present invention as described above, a self-assembled monolayer is formed on the substrate;

[0032] A light-absorbing layer, an electron transport layer, and a top electrode are sequentially formed on the self-assembled monolayer to obtain the solar cell.

[0033] Beneficial effects: The dip-coating process provided by this invention can rapidly form high-quality self-assembled monolayers within a production window of less than 5 minutes, resulting in a certified efficiency of 27.23% for small-area perovskite solar cells with good device stability. This efficient dip-coating process can be extended to the fabrication of large-area and flexible devices. Furthermore, the precursor solution (i.e., the first dispersion) of the self-assembled monolayer material exhibits good reusability, further improving the sustainability of the dip-coating process. Attached Figure Description

[0034] Figure 1 This is a flowchart of a method for preparing a self-assembled monolayer based on a dip-coating process.

[0035] Figure 2 This is a schematic diagram of the process for preparing self-assembled monolayers using dip-coating technology.

[0036] Figure 3 In Example 1, a is a schematic diagram of the structure of the small-area perovskite solar cell, and b is a cross-sectional transmission electron microscope (TEM) image of the small-area perovskite solar cell.

[0037] Figure 4 The current density-voltage (J–V) curve of the small-area rigid substrate perovskite solar cell prepared in Example 1 is shown.

[0038] Figure 5 The graph shows the correlation between the energy conversion efficiency of the solar cell and the number of times the dispersion is reused in Example 1.

[0039] Figure 6 This is a schematic diagram of the recycling process for the ITO substrate with a self-assembled monolayer on its surface in Example 1.

[0040] Figure 7 The J-V curves are the repeatability test results of the efficiency of the solar cells with ITO substrates containing self-assembled monolayers on the surface, which were reused 0 to 3 times in Example 1.

[0041] Figure 8 The image shows the J-V curve of the small-area flexible substrate perovskite solar cell prepared in Example 2.

[0042] Figure 9 The diagram shows the structural schematics of the rigid and flexible modules of the perovskite solar cells in Examples 3 and 4.

[0043] Figure 10 The image shows the J-V curve of the rigid perovskite solar cell module prepared in Example 3.

[0044] Figure 11 The image shows the J-V curve of the flexible perovskite solar cell module prepared in Example 4.

[0045] Figure 12 The image shows the J-V curves of a small-area rigid substrate perovskite solar cell fabricated using a spin-coating process based on a spin coating technique in Comparative Example 1.

[0046] Figure 13The image shows the J-V curves of a small-area flexible substrate perovskite solar cell with a self-assembled monolayer fabricated using spin-coating technology in Comparative Example 2.

[0047] Figure 14 The image shows the J-V curves of the rigid module of the self-assembled monolayer perovskite solar cell prepared by spin coating process in Comparative Example 3.

[0048] Figure 15 The J-V curves are shown for small-area rigid substrate perovskite solar cells based on different self-assembled monolayer materials in Example 5, where a is based on OB-2PACz and b is based on OB-Php2PACz.

[0049] Figure 16 The image shows the J-V curves of small-area rigid substrate perovskite solar cells with self-assembled monolayers prepared using different alcohol-based organic solvent dip-coating processes in Example 6.

[0050] Figure 17 The image shows the J-V curves of small-area rigid substrate perovskite solar cells with self-assembled monolayers prepared using ethanol dip-coating processes with different water contents in Example 7. Detailed Implementation

[0051] This invention provides a method for preparing a self-assembled monolayer based on a dip-coating process, a solar cell, and the same method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0053] In perovskite solar cells, optimization of the hole-selective layer is crucial for improving device efficiency and enhancing overall structural stability. In recent years, self-assembled monolayers have attracted significant attention due to their inherent ultrathin structure, excellent interface passivation effect, and superior hole extraction capability, becoming emerging candidate materials for hole-selective layers. Currently, self-assembled monolayers and their small-area devices prepared by spin-coating based on small organic molecules using carbazole, alkyl chains, and phosphate groups have achieved power conversion efficiencies exceeding 26%.

[0054] Although spin coating is a widely used technique for rapidly preparing high-quality, small-area self-assembled monolayers, it still has significant limitations in large-scale industrial applications and flexible device fabrication. In contrast, dip coating offers advantages such as high material utilization, reproducible batch production, and improved contact between phosphate groups and the conductive oxide substrate surface, making it theoretically more suitable for large-area substrate processing and flexible device fabrication. However, dip coating currently suffers from two main drawbacks: significantly longer processing time than spin coating and lower energy conversion efficiency in the resulting perovskite solar cells. These issues collectively hinder its large-scale commercial application. Therefore, this invention provides a method for rapidly (less than 5 minutes) dip-coating self-assembled monolayers, achieved through collaborative molecular design and solvent engineering. Specifically, it provides a method for preparing self-assembled monolayers based on dip coating, wherein, as... Figure 1 As shown, it includes the following steps:

[0055] S1. A first dispersion is provided, the first dispersion comprising a first solvent and a self-assembled monolayer material; the first solvent is a first alcohol-based organic solvent, or the first solvent is a mixture of a first alcohol-based organic solvent and water; the self-assembled monolayer material contains at least one alkoxy group at its terminal position;

[0056] S2. Immerse the substrate in the first dispersion, let it stand for a first preset time, then remove it and perform a first annealing. Then immerse it in a second alcohol organic solvent for a second preset time, then remove it and perform a second annealing to obtain the self-assembled monolayer. The first preset time is greater than 0 min and less than or equal to 5 min.

[0057] like Figure 2 As shown, the preparation method of the self-assembled monolayer in this invention is briefly described as follows: first, dip coating is performed to form a multilayer structure on the substrate surface, and then the substrate is immersed in a second alcohol organic solvent for washing, and finally a uniform self-assembled monolayer (i.e., a monomolecular self-assembled layer) is formed on the substrate surface.

[0058] This invention, through rational molecular design and appropriate solvent engineering, enables self-assembled monolayer materials with terminal alkoxy groups to form hydrogen-bonded functional groups with a first alcohol-based organic solvent in the first solvent. This enhances the dispersibility of the self-assembled monolayer material in the first solvent, increases the self-assembled monolayer assembly density, and accelerates self-assembly on the substrate surface during dip-coating. The dip-coating process provided by this invention can rapidly form high-quality self-assembled monolayers within a production window of less than 5 minutes, achieving a certified efficiency of 27.23% for small-area perovskite solar cells with good device stability. This efficient dip-coating process can be extended to the fabrication of large-area and flexible devices. This process effectively reduces device fabrication time, improves device production cycle time, and truly realizes the feasibility of industrial-scale production.

[0059] Furthermore, the precursor solution (i.e., the first dispersion) and the post-immersion solution (i.e., the second alcohol-based organic solvent) of the self-assembled monolayer material exhibit good reusability, further improving the sustainability of the dip coating process.

[0060] In step S1, in some embodiments, the first solvent consists of a first alcohol-based organic solvent and water comprising 0 vol% to 6.0 vol% (e.g., 0 vol%, 0.5 vol%, 1 vol%, 1.5 vol%, 2 vol%, 2.5 vol%, 3 vol%, 3.5 vol%, 4 vol%, 4.5 vol%, 5 vol%, 5.5 vol%, or 6 vol%) of the first alcohol-based organic solvent. Preferably, the first solvent consists of a first alcohol-based organic solvent and water comprising 1.5 vol% of the first alcohol-based organic solvent. The addition of water can increase the dielectric constant of the solution and improve the dissolution of self-assembled monolayer materials.

[0061] In some embodiments, the first alcoholic organic solvent includes at least one selected from methanol, ethanol, isopropanol, and n-propanol. These alcoholic organic solvents are inexpensive, have low toxicity, and readily form hydrogen bonds with alkoxy groups in the self-assembled monolayer material, thereby enhancing the dispersibility of the self-assembled monolayer material.

[0062] In this invention, the concentration of the self-assembled monolayer material in the first dispersion has little impact on the final dip-coating effect, and the process has a wide tolerance range for solution concentration. However, the optimal concentration of the self-assembled monolayer material in the first dispersion is 2.5 mM.

[0063] In some embodiments, the method for preparing the first dispersion includes the following steps:

[0064] The self-assembled monolayer material is mixed with a first solvent and ultrasonically treated for 10–20 min (e.g., 10 min, 12 min, 15 min, 18 min, or 20 min). Then, it is stirred at 50–60 °C (e.g., 50 °C, 52 °C, 55 °C, 58 °C, or 60 °C) for 20–24 h (e.g., 20 h, 21 h, 22 h, 23 h, or 24 h) to obtain a first dispersion.

[0065] In this embodiment, the self-assembled monolayer material is fully dispersed in the first dispersion.

[0066] In some embodiments, the self-assembled monolayer material contains at least one C1-C60 alkoxy group at its terminal sites. In some embodiments, the self-assembled monolayer material also contains phosphonic acid groups. The aforementioned first solvent readily forms hydrogen bonds with the phosphonic acid groups and alkoxy groups in the self-assembled monolayer material, thereby providing it with good dispersibility in the first solvent.

[0067] In some embodiments, the general chemical structural formula of the self-assembled monolayer material is:

[0068] L can be a conjugated linker or a non-conjugated linker;

[0069] The electron donor is selected from

[0070]

[0071]

[0072]

[0073] One of them;

[0074] Among them, R1-R 14 Each of the following is independently derived from one of the following groups: hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidine, hydrazine, hydrazone, C1-C60 alkyl, C2-C60 alkenyl, C2-C60 alkoxy, C3-C60 cycloalkyl, C1-C10 heterocyclic alkyl, C3-C10 cycloalkenyl, C1-C10 heterocyclic alkenyl, C6-C60 aryl, C1-C60 heteroaryl, monovalent non-aromatic condensed polycyclic, monovalent non-aromatic condensed heteropolycyclic, biphenyl, and terphenyl, and R1-R 14 At least one of them is a C1-C60 alkoxy group.

[0075] In some embodiments, L is selected from alkyl (non-conjugated linking group); or L is selected from one of the following conjugated linking groups:

[0076]

[0077]

[0078] Based on the inventor's previous patent CN 117659083 A (where L is a conjugated linking group, the corresponding self-assembled monolayer material originates from this patent), it has been shown that replacing traditional alkyl chains with rigid phenyl linking chains in self-assembled monolayer materials can enhance material stability, improve molecular rigidity, and increase their packing density on transparent conductive oxide substrates. These structural optimizations collectively promote interfacial carrier transport, thereby further improving the efficiency and stability of the device.

[0079] In some specific embodiments, the self-assembled monolayer material includes

[0080] At least one of them.

[0081] In step S2, in some embodiments, the substrate is a rigid substrate or a flexible substrate;

[0082] The rigid substrate includes a glass substrate and a transparent conductive oxide (TCO) layer on the surface of the glass substrate. In some specific embodiments, the TCO layer includes a fluorine-doped tin oxide (FTO) layer, an indium tin oxide (ITO) layer, or an aluminum-doped zinc oxide (AZO) layer;

[0083] In some embodiments, the flexible substrate includes a polymer substrate and a TCO layer located on the surface of the polymer substrate, the TCO layer including an FTO layer, an ITO layer or an AZO layer.

[0084] In some embodiments, the polymer substrate is a polyethylene naphthalate (PEN) substrate.

[0085] In some embodiments, the temperature of the first annealing is 110-120°C (e.g., 110°C, 112°C, 115°C, 118°C, or 120°C), and the time of the first annealing is 15-20 min (e.g., 15 min, 16 min, 17 min, 18 min, 19 min, or 20 min).

[0086] In some embodiments, the temperature of the second annealing is 110-120°C (e.g., 110°C, 112°C, 115°C, 118°C, or 120°C), and the time of the second annealing is 10-20 min (e.g., 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, or 20 min).

[0087] In some embodiments, the second alcohol-based organic solvent includes at least one of isopropanol, ethanol, and n-propanol. The purpose of immersing the device in the second alcohol-based organic solvent for a predetermined time is to remove excess self-assembled monomolecules that have not formed a self-assembled monolayer, thereby improving the performance of the solar cell device.

[0088] In some embodiments, the preset time is 0.4 to 0.5 minutes (e.g., 24 seconds, 25 seconds, 26 seconds, 27 seconds, 28 seconds, 29 seconds, or 30 seconds). This time is sufficient to remove excess self-assembled monomolecules.

[0089] This invention also provides a solar cell, wherein the solar cell includes a substrate, a self-assembled monomolecule, a light-absorbing layer, an electron transport layer and a top electrode stacked sequentially, and the self-assembled monomolecule is prepared by the preparation method of this invention as described above.

[0090] This invention also provides a method for preparing a solar cell, comprising the following steps:

[0091] Provide substrate;

[0092] Using the preparation method of the present invention as described above, a self-assembled monolayer is formed on the substrate;

[0093] A light-absorbing layer, an electron transport layer, and a top electrode are sequentially formed on the self-assembled monolayer to obtain the solar cell.

[0094] In this embodiment, the light-absorbing layer can be prepared by spin coating, and the electron transport layer can be prepared by thermal evaporation.

[0095] The present invention will be further described below through specific embodiments.

[0096] In the following embodiments, some symbols have the following meanings.

[0097] DMF: N,N-dimethylformamide;

[0098] DMSO: Dimethyl sulfoxide;

[0099] FAI: Formamidin iodide;

[0100] MACl: Methylamine ammonium chloride;

[0101] pF-PEAAc: p-Fluorophenylethyl acrylic acid;

[0102] PI: Polyimide;

[0103] IPA: Isopropyl ketone;

[0104] 3MTPAI: 3-Methylthiopropylammonium iodide;

[0105] NMP: N-methylpyrrolidone;

[0106] EDAI2: Ethylenediamine diiodide;

[0107] BCP: Bathing Copper Spirit.

[0108] Example 1: Small-area rigid substrate perovskite solar cell and its fabrication method

[0109] In this embodiment, the self-assembled monolayer material is selected. (Written as OB-PhpPACz).

[0110] This invention provides a small-area rigid substrate perovskite solar cell (a small-area rigid substrate perovskite solar cell with a 1.53 eV bandgap), such as... Figure 3 As shown, it is an inverted planar heterojunction structure, including a transparent conductive substrate (composed of a glass substrate and an ITO layer on the surface of the glass substrate, referred to as the ITO substrate), a self-assembled monolayer based on OB-PhpPACz (i.e., the SAM layer), a perovskite light-absorbing layer, an electron transport layer (composed of a C60 layer and a tin oxide layer), and a copper electrode stacked sequentially from bottom to top.

[0111] This embodiment also provides a method for fabricating a small-area rigid substrate perovskite solar cell, including the following steps:

[0112] (1) Cleaning the ITO substrate

[0113] The etched ITO substrate was ultrasonically treated in cleaning agent, deionized water, anhydrous ethanol, acetone and isopropanol for 15 minutes in sequence. After being removed, it was dried with clean air and placed in an oven to dry at 120°C for 8 hours, followed by ultraviolet ozone treatment for 30 minutes.

[0114] (2) Prepare self-assembled monolayers on ITO layers of ITO substrates using dip-coating process.

[0115] OB-PhpPACz was dissolved in an ethanol solvent containing 1.5 vol% deionized water (i.e., deionized water accounts for 1.5 vol% of the ethanol volume), sonicated for 20 minutes, and then stirred at 50°C for 24 hours to obtain a dispersion of OB-PhpPACz with a concentration of 2.5 mM. An ITO substrate (dimensions: 15 mm × 15 mm, ITO layer thickness 200 nm) was immersed in this dispersion and allowed to stand for 5 minutes before removal. Subsequently, the coated ITO substrate was annealed on a hot plate at 120°C for 15 minutes to obtain an ITO substrate with a self-assembled monolayer on its surface. To wash away excess self-assembled monolayer material, the ITO substrate with the self-assembled monolayer was immersed in isopropanol, allowed to stand for 0.5 minutes, and then annealed on a hot plate at 120°C for 10 minutes.

[0116] (3) Preparation of perovskite precursor solution and passivation solution

[0117] CsI ​​(12.9 mg), FAI (332.5 mg), PbI2 (810.3 mg), PbCl2 (17.9 mg), MACl (14.6 mg), and pF-PEAAc (1.5 mg) were dissolved in 1 mL of a mixed solvent (composed of DMF and DMSO in a volume ratio of 4:1) and shaken at 45 °C for 1 hour to obtain a perovskite precursor solution.

[0118] Two passivation solutions were prepared: PI solution: 0.5 mg PI was dissolved in 1 mL IPA and stirred for 24 hours. 3MTPAI solution: 0.5 mg 3MTPAI was dissolved in 1 mL IPA and stirred for 24 hours.

[0119] (4) Preparation of perovskite light-absorbing layer

[0120] In a nitrogen-filled glove box, perovskite films were deposited onto self-assembled monolayers using solvent engineering. A perovskite precursor solution was coated onto the self-assembled monolayer and spin-coated in two steps: spin-coating at 1000 rpm for 7 s (first step), followed by spin-coating at 5000 rpm for 55 s (second step). The spin-coating temperature was controlled at 22 °C. With 8 seconds remaining in the second spin-coating step, 180 μL of the antisolvent ethyl acetate was slowly added dropwise to the center of the rotating ITO substrate. The substrate was then annealed at 100 °C for 20 min to obtain the perovskite layer.

[0121] (5) Post-passivation treatment

[0122] The PI solution was statically dropped onto the surface of the perovskite layer, then spin-coated at 4000 rpm for 30 s, followed by annealing at 100 °C for 6 min. Subsequently, the surface was rinsed with 3 MTPAI solution at 5000 rpm, and then annealed again at 100 °C for 2 min. The thickness of the prepared perovskite light-absorbing layer (composition CsFAPbI3) was approximately 700 nm, as measured by cross-sectional SEM images.

[0123] (6) Fabrication of an electron transport layer on a perovskite light-absorbing layer

[0124] In a vacuum chamber, at a temperature below 4 × 10⁻⁶ -6 Under pressure of Pa, a 40 nm thick C60 layer is thermally evaporated and then transferred to an atomic layer deposition (ALD) system (SUPERALD, LLC) to deposit a 100-cycle tin oxide layer (99.9999% purity, 10 nm thickness) at 80 °C to obtain an electron transport layer.

[0125] (7) Fabrication of copper electrodes on nickel oxide layer

[0126] Below 4×10 -6 Under Pa pressure, A copper electrode was fabricated by evaporation deposition on the nickel oxide layer at a high rate, with the copper electrode thickness controlled to 100 nm. The device was then encapsulated. Finally, an anti-reflective film (Mitsubishi) was attached to the glass surface of the device, resulting in a rigid substrate perovskite solar cell (effective area 0.0715 cm²). 2 ).

[0127] The small-area rigid substrate perovskite solar cells prepared above were tested under the following conditions: spectral distribution AM1.5G, and illumination intensity of 100 mW / cm². 2 The AAA solar simulator (Beijing Zhuoli Hanguang Company) was used, and the JV curve was measured using a Keithly 2400 digital source meter.

[0128] Test results are as follows Figure 4 As shown, the optimal photoelectric conversion efficiency parameter for small-area rigid substrate perovskite solar cells is: open-circuit voltage (Voltage, i.e., V). oc The voltage is 1.191V, and the short-circuit current density (i.e., J) is 1.191V. sc The value is 26.37 mA / cm. 2 The fill factor (FF) is 86.24%, and the conversion efficiency (PCE) is 27.09%. After being stored in an atmospheric environment for 3000 hours, the device still maintains more than 99% of its initial efficiency.

[0129] Furthermore, the dispersion used in the rapid dip-coating process (the composition of which is detailed in step (2) above) is highly reusable. A statistical analysis was performed on the amount of dispersion used in this process, i.e., the same dispersion was used to dip-coat multiple batches of FTO transparent conductive substrates. For example... Figure 5 As shown, even after 20 reuses, perovskite solar cell devices retain over 97% of the performance of the initial batch. The material consumption of the rapid dip-coating process is only one-quarter of that of the traditional spin-coating process.

[0130] The self-assembled monolayer based on OB-PhpPACz is prepared via a dip-coating process, exhibiting a certain degree of solvent resistance, thus enabling the recyclability of the completed solar cell device. For example... Figure 6 As shown, the solar cells prepared in Example 1 were subjected to ultrasonic treatment in water, and perovskite, C60, and tin oxide (SnO) were used to treat the cells. x The copper electrode will be separated from the ITO substrate containing a self-assembled monolayer on its surface. For example... Figure 7 As shown, solar cells fabricated using ITO substrates with self-assembled monolayers on their surface can still achieve a PCE (power conversion efficiency) of over 26% even after two recycling cycles.

[0131] Example 2: Small-area flexible substrate perovskite solar cell and its fabrication method

[0132] This embodiment provides a small-area flexible substrate perovskite solar cell (i.e., a small-area flexible substrate perovskite solar cell with a bandgap of 1.53 eV) and its fabrication method. The only difference from Example 1 is that the transparent conductive substrate used is a PEN-ITO substrate (i.e., it is composed of a PEN substrate and an ITO layer on the surface of the PEN substrate, wherein the thickness of the ITO layer is 200 nm and the size is the same as the substrate in Example 1).

[0133] The fabricated small-area flexible substrate perovskite solar cell was tested under the same conditions as in Example 1, and the test results are as follows. Figure 8 As shown, the optimal photoelectric conversion efficiency parameters for small-area flexible substrate perovskite solar cells are: open-circuit voltage of 1.185V and short-circuit current density of 25.44mA / cm². 2 The fill factor is 82.89%, and the conversion efficiency is 24.98%.

[0134] Example 3 4.5×4.5cm 2 Rigid Perovskite Solar Cell Module and Its Fabrication Method

[0135] This embodiment provides a rigid perovskite solar cell module and its fabrication method. Specifically, the rigid perovskite solar cell module is an inverted planar heterojunction perovskite solar cell rigid module. Figure 9 As shown, it includes an ITO substrate, a self-assembled monolayer based on OB-PhpPACz, a perovskite light-absorbing layer, an electron transport layer (C60 / BCP), and a silver electrode, which are stacked sequentially from bottom to top.

[0136] This embodiment also provides a method for preparing a rigid module of a perovskite solar cell, including the following steps:

[0137] (1) Cleaning the ITO substrate: Same as in Example 1.

[0138] (2) Preparation of self-assembled monolayer using dip coating process: The ITO substrate used has a length × width of 4.5cm × 4.5cm, and the rest is the same as in Example 1.

[0139] (3) Preparation of perovskite precursor solution and additives: FAI (285.5 mg), CsI (88.3 mg), PbI2 (922.0 mg), and PbCl2 (55.6 mg) were dissolved in a mixed solution of DMF (1 mL) and NMP (0.192 mL) to obtain perovskite precursor solution.

[0140] Dissolve 0.3 mg EDAI2 in 1 mL IPA and stir for 24 h to obtain an additive EDAI2 solution.

[0141] (4) Perovskite light-absorbing layer (composed of FA) 0.83 Cs 0.17 Preparation of PbI3: In a nitrogen-filled glove box, 1000 μL of perovskite precursor solution was spin-coated onto a self-assembled monolayer at 5000 rpm for 6 seconds (acceleration: 1000 rpm / s). The wet film was transferred to a vacuum flash evaporation system (pressure: 5 Pa) to remove the solvent and crystallize, and then annealed at 150 °C for 10 min at a relative humidity (RH) of 10% to form a perovskite layer.

[0142] (5) Post-passivation treatment: Spin-coat 300 μL of EADI2 solution onto the perovskite layer at a speed of 5000 rpm for 30 seconds (acceleration: 2000 rpm / s), and then anneal at 100℃ for 10 min to obtain the perovskite light-absorbing layer.

[0143] (6) Preparation of electron transport layer and silver electrode: C60 (40nm), BCP (5nm) and silver (100nm) are thermally evaporated in a vacuum chamber in sequence.

[0144] (7) Post-processing of the module: The interconnects of P1, P2, and P3 were laser-patterned using a 355nm laser beam (power: 5W; current: 1A; scribing speed: 550mm / s; pulse width: 20μs). The scribing frequencies for P1, P2, and P3 were 39.5kHz, 44.5kHz, and 44.5kHz, respectively. The scribing of P1 was performed on the cleaned (before dip coating) ITO substrate. The scribing of P2 was performed after the deposition of the perovskite light-absorbing layer and the C60 / BCP layer. The scribing of P3 was performed after the evaporation of the silver (Ag) electrode. The linewidths of P1, P2, and P3 were approximately 100μm. Finally, an anti-reflection coating (Mitsubishi) was attached to the glass surface of the device to obtain a rigid perovskite solar cell module (effective area 12cm²). 2 ).

[0145] Testing: The rigid perovskite solar cell module prepared in this embodiment was tested under the same conditions as in Example 1.

[0146] Test results are as follows Figure 10 As shown, the optimal photoelectric conversion efficiency parameters for the rigid perovskite solar cell module are: open-circuit voltage of 5.90V and short-circuit current density of 5.00mA / cm². 2 The fill factor is 78.81%, and the conversion efficiency is 23.25%.

[0147] Example 4 13×13cm 2 Flexible Perovskite Solar Cell Module and Its Fabrication Method

[0148] This embodiment provides a flexible perovskite solar cell module and its fabrication method. Specifically, the flexible perovskite solar cell module is an inverted planar heterojunction perovskite solar cell module. Figure 9 As shown, it includes an ITO substrate (set on PEN), a self-assembled monolayer based on OB-PhpPACz, a perovskite light-absorbing layer, an electron transport layer (C60 / BCP), and a silver electrode stacked sequentially from bottom to top.

[0149] The specific steps involved in fabricating a flexible perovskite solar cell module are as follows:

[0150] (1) Preparing the PEN-ITO substrate: Use double-sided tape to attach the PEN-ITO substrate to the rigid glass carrier for processing, resulting in dimensions of 13×13cm (length × width). 2 PEN-ITO substrate.

[0151] (2) Preparation of self-assembled monolayers using dip coating process: same as in Example 1.

[0152] (3) Preparation of perovskite precursor solution and additives: Same as in Example 3.

[0153] (4) Preparation of the perovskite light-absorbing layer: In a nitrogen-filled glove box, 8000 μL of perovskite precursor solution was spin-coated onto the self-assembled monolayer at a speed of 5000 rpm for 6 seconds (acceleration: 1000 rpm / s). The wet film was transferred to a vacuum flash evaporation system (pressure: 5 Pa) to remove the solvent and crystallize, and then annealed at 150 °C for 10 min in an environment with a relative humidity (RH) of 10% to obtain the perovskite layer.

[0154] (5) Post-passivation treatment: Spin-coat 1500 μL of EADI2 solution onto the perovskite layer at a speed of 5000 rpm for 30 seconds (acceleration: 2000 rpm / s), and then anneal at 100℃ for 10 minutes to obtain the perovskite light-absorbing layer.

[0155] (6) Preparation of electron transport layer and silver electrode: Same as in Example 3.

[0156] (7) Post-processing of the module: The interconnects of P1, P2, and P3 were laser-patterned using a 355nm laser beam (power: 5W; current: 1A; scribing speed: 550mm / s; pulse width: 20μs). The scribing frequencies for P1, P2, and P3 were 41kHz, 44.5kHz, and 44.5kHz, respectively. Scribing of P1 was performed on the cleaned substrate (before dip coating). Scribing of P2 was performed after the deposition of the perovskite layer and the C60 / BCP layer. Scribing of P3 was performed after the evaporation of the silver (Ag) electrode. The linewidths of P1, P2, and P3 were approximately 100μm. Finally, an anti-reflective coating (Mitsubishi) was attached to the glass surface of the device to obtain a flexible perovskite solar cell module (effective area 75cm²). 2 ).

[0157] Testing: The flexible perovskite solar cell module prepared in this embodiment was tested under the same conditions as in Example 3. The test results are as follows: Figure 11 As shown, the optimal photoelectric conversion efficiency parameters for the flexible perovskite solar cell module are: open-circuit voltage of 19.90V and short-circuit current density of 93.94mA / cm². 2 The fill factor is 66.58%, and the conversion efficiency is 16.60%.

[0158] Comparative Example 1

[0159] This comparative example provides a small-area rigid substrate perovskite solar cell (1.53eV bandgap small-area rigid substrate perovskite solar cell) and its preparation method. The only difference from Example 1 is that a spin-coating process is used to prepare a self-assembled monolayer.

[0160] Spin-coating process: The dispersion was spin-coated onto the ITO substrate at 3000 rpm for 30 seconds, and then annealed on a hot plate at 120°C for 10 minutes to obtain an ITO substrate with a self-assembled monolayer on the surface. Subsequently, the ITO substrate with the self-assembled monolayer on the surface was dynamically rinsed with 100 μL of isopropanol at 5000 rpm, and finally annealed on a hot plate at 120°C for 10 minutes.

[0161] The small-area rigid substrate perovskite solar cell prepared in this comparative example was tested under the same conditions as in Example 1. The test results are as follows. Figure 12 As shown, the optimal photoelectric conversion efficiency parameters for small-area rigid substrate perovskite solar cells are: open-circuit voltage of 1.176V and short-circuit current density of 26.25mA / cm². 2 The fill factor is 79.23%, and the conversion efficiency is 24.46%.

[0162] Comparative Example 2

[0163] This comparative example provides a small-area flexible substrate perovskite solar cell (1.53eV bandgap small-area flexible substrate perovskite solar cell) and its preparation method. The only difference from Example 2 is that a spin coating process is used to prepare a self-assembled monolayer, and the spin coating process is the same as that of Comparative Example 1.

[0164] The small-area flexible substrate perovskite solar cell prepared in this comparative example was tested under the same conditions as in Example 2. The test results are as follows: Figure 13 As shown, the optimal photoelectric conversion efficiency parameters for small-area flexible substrate perovskite solar cells are: open-circuit voltage of 1.179V and short-circuit current density of 25.42mA / cm³. 2 The fill factor is 79.87%, and the conversion efficiency is 23.93%.

[0165] Comparative Example 3

[0166] This comparative example provides a rigid perovskite solar cell module (4.5×4.5cm). 2 The perovskite solar cell rigid module and its preparation method differ from those in Example 3 only in that a spin-coating process is used to prepare a self-assembled monolayer.

[0167] Spin coating process: 1000 μL of dispersion was spin-coated onto the ITO substrate at 4000 rpm for 30 seconds (acceleration: 1000 rpm / s). Annealing and rinsing steps were the same as those in Comparative Example 1.

[0168] The rigid perovskite solar cell module prepared in this comparative example was tested under the same conditions as in Example 3. The test results are as follows. Figure 14As shown, the optimal photoelectric conversion efficiency parameters for the rigid perovskite solar cell module are: open-circuit voltage of 5.89V and short-circuit current density of 5.01mA / cm². 2 The fill factor is 74.49%, and the conversion efficiency is 21.98%.

[0169] The test results of Examples 1-3 and Comparative Examples 1-3 are summarized in Table 1.

[0170] Table 1. Test results of Examples 1-3 and Comparative Examples 1-3

[0171]

[0172] Example 5

[0173] This embodiment provides a small-area rigid substrate perovskite solar cell and its fabrication method. The only difference from Embodiment 1 is that OB-PhpPACz is replaced with OB-2PACz. and OB-Php2PACz

[0174]

[0175] The small-area rigid substrate perovskite solar cell in this embodiment was tested under the same conditions as in Embodiment 1, and the test results are as follows. Figure 15 As shown, the optimal photoelectric conversion efficiency parameters for the small-area rigid substrate perovskite solar cell based on OB-2PACz are: open-circuit voltage of 1.178V and short-circuit current density of 26.21mA / cm². 2 The fill factor is 84.18%, and the conversion efficiency is 25.99%.

[0176] The optimal photoelectric conversion efficiency parameters for small-area rigid substrate perovskite solar cells based on OB-Php2PACz are: open-circuit voltage of 1.188V and short-circuit current density of 26.25mA / cm². 2 The fill factor is 84.82%, and the conversion efficiency is 26.45%.

[0177] Example 6

[0178] This embodiment provides a small-area rigid substrate perovskite solar cell and its preparation method. The only difference from Example 1 is that OB-PhpPACz is dissolved in methanol (MeOH), ethanol (EtOH), n-propanol (PrOH), and isopropanol (IPA) respectively to obtain a dispersion and prepare a self-assembled monolayer.

[0179] The test conditions for the small-area rigid substrate perovskite solar cell in this embodiment are the same as those in Example 1. The test results for the small-area rigid substrate perovskite solar cell are as follows: Figure 16 As shown in Table 2, the optimal photoelectric conversion efficiency parameters for small-area rigid substrate perovskite solar cells are:

[0180] Small-area rigid substrate perovskite solar cell based on methanol (MeOH): Open-circuit voltage 1.191V, short-circuit current density 26.10mA / cm² 2 The fill factor is 84.21%, and the conversion efficiency is 26.18%.

[0181] Small-area rigid substrate perovskite solar cell based on ethanol (EtOH): Open-circuit voltage 1.191V, short-circuit current density 26.29mA / cm² 2 The fill factor is 84.51%, and the conversion efficiency is 26.46%.

[0182] Small-area rigid substrate perovskite solar cell based on n-propanol (PrOH): Open-circuit voltage 1.188V, short-circuit current density 26.02mA / cm² 2 The fill factor is 78.88%, and the conversion efficiency is 24.38%.

[0183] Small-area rigid substrate perovskite solar cell based on isopropanol (IPA): Open-circuit voltage 1.190V, short-circuit current density 26.01mA / cm² 2 The fill factor is 79.53%, and the conversion efficiency is 24.62%.

[0184] Table 2. Test results of small-area rigid substrate perovskite solar cells in Example 6

[0185]

[0186] Example 7

[0187] This embodiment provides a small-area rigid substrate perovskite solar cell and its preparation method. The only difference from Embodiment 1 is that OB-PhpPACz is dissolved in ethanol solvent containing 0 vol%, 0.5 vol%, 1 vol%, 1.5 vol%, 3 vol%, and 6 vol% deionized water to obtain dispersions and prepare self-assembled monolayers.

[0188] The test conditions for the small-area rigid substrate perovskite solar cell in this embodiment are the same as those in Example 1. The test results for the small-area rigid substrate perovskite solar cell are as follows: Figure 17 As shown in Table 3.

[0189] Table 3. Test results of small-area rigid substrate perovskite solar cells in Example 7

[0190]

[0191] The test results above show that the best results can be obtained when the volume fraction of water is 1.5 vol%.

[0192] In summary, this invention provides a rapid (less than 5 minutes) immersion-based self-assembled monolayer film preparation strategy achieved through co-engineering molecular design and solvent engineering. Alkoxy-containing self-assembled monolayer materials can be well dispersed in aqueous or non-aqueous alcohol organic solvents and exhibit enhanced anchoring on a transparent conductive oxide substrate. The substrate surface after immersion coating has a dense and uniform capping layer (i.e., a dense and uniform self-assembled monolayer), and the fabricated perovskite solar cell achieves a certified power conversion efficiency of up to 27.23%. This method demonstrates good scalability, successfully extending to large-area devices, micro-modules, and flexible architectures, all while maintaining stable operation. Notably, both the initial dispersion and the substrate containing the self-assembled monolayer are reusable, significantly improving resource efficiency. This invention provides an effective self-assembled monolayer molecular design strategy and establishes a scalable and cost-effective technical framework for fabricating stable perovskite solar cells, helping to bridge the gap between laboratory-scale innovation and industrial applications.

[0193] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing a self-assembled monolayer based on a dip-coating process, characterized in that, Includes the following steps: A first dispersion is provided, the first dispersion comprising a first solvent and a self-assembled monolayer material; the first solvent is a first alcohol-based organic solvent, or the first solvent is a mixture of a first alcohol-based organic solvent and water; the self-assembled monolayer material contains at least one alkoxy group at its terminal position; The substrate is immersed in the first dispersion, left to stand for a first preset time, then removed and subjected to a first annealing. It is then immersed in a second alcohol-based organic solvent for a second preset time and subjected to a second annealing to obtain the self-assembled monolayer. The first preset time is greater than 0 min and less than or equal to 5 min.

2. The preparation method according to claim 1, characterized in that, The first solvent consists of a first alcohol-based organic solvent and water, which accounts for 0 vol% to 6.0 vol% of the volume fraction of the first alcohol-based organic solvent.

3. The preparation method according to claim 1, characterized in that, The first alcoholic organic solvent includes at least one of methanol, ethanol, isopropanol, and n-propanol.

4. The preparation method according to claim 1, characterized in that, The preparation method of the first dispersion includes the following steps: The self-assembled monolayer material is mixed with the first solvent, ultrasonicated for 10–20 min, and then stirred at 50–60 °C for 20–24 h to obtain the first dispersion.

5. The preparation method according to claim 1, characterized in that, The second alcoholic organic solvent includes at least one of isopropanol, ethanol, and n-propanol; and / or, The second preset time is 0.4 to 0.5 minutes.

6. The preparation method according to claim 1, characterized in that, The temperature of the first annealing is 110–120°C, and the time of the first annealing is 15–20 min; and / or, The temperature of the second annealing is 110-120℃, and the time of the second annealing is 10-20 minutes.

7. The preparation method according to claim 1, characterized in that, The substrate is a rigid substrate or a flexible substrate; The rigid substrate includes a glass substrate and a transparent conductive oxide layer located on the surface of the glass substrate; The flexible substrate includes a polymer substrate and a transparent conductive oxide layer located on the surface of the polymer substrate.

8. The preparation method according to claim 1, characterized in that, The general chemical structural formula of the self-assembled monolayer material is: L can be a conjugated linker or a non-conjugated linker; The electron donor is selected from One of them; in, Indicates the connection site, R1-R 14 Each of the following is independently derived from one of the following groups: hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidine, hydrazine, hydrazone, C1-C60 alkyl, C2-C60 alkenyl, C2-C60 alkoxy, C3-C60 cycloalkyl, C1-C10 heterocyclic alkyl, C3-C10 cycloalkenyl, C1-C10 heterocyclic alkenyl, C6-C60 aryl, C1-C60 heteroaryl, monovalent non-aromatic condensed polycyclic, monovalent non-aromatic condensed heteropolycyclic, biphenyl, and terphenyl, and R1-R 14 At least one of them is a C1-C60 alkoxy group.

9. A solar cell, characterized in that, The solar cell comprises a substrate, a self-assembled monomolecule, a light-absorbing layer, an electron transport layer, and a top electrode stacked sequentially, wherein the self-assembled monomolecule is prepared by the preparation method according to any one of claims 1-8.

10. A method for preparing a solar cell, characterized in that, Includes the following steps: Provide substrate; A self-assembled monolayer is formed on the substrate using the preparation method according to any one of claims 1-8; A light-absorbing layer, an electron transport layer, and a top electrode are sequentially formed on the self-assembled monolayer to obtain the solar cell.

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