A dynamic cross-linking polymer additive containing aromatic disulfide bond and urea group / amino ester group and its application in perovskite solar cell

Abstract

The application discloses a dynamic cross-linking polymer additive containing aromatic disulfide bond and urea group / urethane group and application thereof in perovskite solar cells. The additive is formed in-situ during perovskite film formation by free radical polymerization reaction of cross-linkable monomer A and cross-linking agent B. The additive constructs a dynamic polymer network at perovskite grain boundaries, in which the strong coordination groups of urea group / urethane group form coordination bonds and hydrogen bonds with lead ions, halogen ions and organic cations in perovskite, passivate intrinsic defects and optimize the crystallization process, significantly improve photoelectric conversion efficiency; the reversible exchange reaction of aromatic disulfide bond at room temperature endows the device with the ability of room temperature rapid autonomous repair of mechanical bending cracks without external field triggering, and synchronously restores electrical performance; at the same time, the dense cross-linking network acts as a physical barrier to inhibit long-range migration of halogen ions excited by ultraviolet light and block water and oxygen erosion, greatly enhancing the ultraviolet light stability of the device. The application synchronously realizes device efficiency improvement, room temperature rapid self-repair and ultraviolet stability enhancement by constructing a dynamic cross-linking polymer network at perovskite grain boundaries, providing an effective solution to the comprehensive stability problem of perovskite solar cells in dynamic use environment.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic materials and devices technology, specifically relating to a dynamic crosslinked polymer additive containing aromatic disulfide bonds and urea / urethane groups, its preparation method, and the application of the additive in perovskite solar cells, especially in improving the photoelectric conversion efficiency of the cell, autonomously and rapidly repairing mechanical cracks at room temperature and simultaneously restoring device efficiency, and enhancing the stability under ultraviolet light. Background Technology

[0002] Perovskite solar cells (PSCs) have become a research hotspot in the photovoltaic field due to their high efficiency and low cost, with laboratory-certified photoelectric conversion efficiencies exceeding 27%. However, their commercialization is limited by insufficient device stability, especially performance degradation under outdoor illumination and flexible bending conditions. Perovskite polycrystalline thin films possess soft lattice characteristics and contain numerous internal defects, making them prone to degradation under the coupled effects of multiple factors such as light, electricity, heat, and force. Among these, ultraviolet light exposure and mechanical bending are two major failure inducing factors. High-energy ultraviolet photons exacerbate halide ion migration, initiating side reactions at the interface, leading to halogen vacancies and uncoordinated Pb. 2+ The accumulation of defects leads to an irreversible decrease in open-circuit voltage and fill factor. The brittleness of perovskite films causes microcracks to form under repeated bending stress, disrupting charge transport paths and exposing new interfaces that accelerate environmental corrosion, resulting in a sharp decline in the electrical performance of the device.

[0003] To address the aforementioned stability challenges, self-healing materials can be introduced. Thermally triggered self-healing polymers based on disulfide bond exchange reactions can heal macroscopic cracks under heating conditions. However, these materials still have the following shortcomings: (1) the repair depends on external thermal triggering, which may exacerbate the thermal instability of perovskites; (2) the repair time is long (several hours), making it difficult to meet the immediate needs of dynamic use environments; (3) only the morphological healing of cracks is considered, without demonstrating the simultaneous recovery of electrical properties; and (4) they cannot simultaneously suppress performance degradation caused by ultraviolet light.

[0004] Recently, the "in-situ crosslinking" strategy has provided a new approach for constructing reinforced networks within perovskite films without significantly compromising efficiency. However, the crosslinked networks constructed by this technology are currently mostly static, or possess only slow, externally-dependent limited response capabilities, and cannot yet achieve "rapid self-repair" under "room temperature conditions." More importantly, there is still no design that can simultaneously and efficiently address two different mechanisms of damage: "UV-induced electrical degradation" and "bending-induced mechanical failure."

[0005] Therefore, developing an additive that can rapidly repair mechanical cracks at room temperature and simultaneously restore device performance while enhancing UV stability is of great significance for promoting the practical application of perovskite photovoltaic technology. Summary of the Invention

[0006] This invention provides a dynamic crosslinked polymer containing aromatic disulfide bonds and urea / urethane groups, which is introduced as an additive into perovskite solar cells to construct a dynamic polymer network at the perovskite grain boundaries. This can significantly improve the photoelectric conversion efficiency of the device and enhance its ultraviolet stability. For flexible devices, it can also enable rapid self-repair of mechanical bending cracks at room temperature and simultaneous recovery of device efficiency.

[0007] The technical solution adopted in this invention is as follows: a dynamic crosslinking polymer additive for perovskite solar cells is provided, characterized in that the additive is formed in situ during the perovskite film formation process by crosslinkable monomer A and crosslinking agent B through mercapto-olefin click reaction or free radical polymerization reaction.

[0008] Furthermore, the crosslinkable monomer A is a bifunctional molecule containing aromatic disulfide bonds, urea / urethane groups, and polymeric ethylene end groups, and its general structural formula is shown in formulas (I) to (IV):

[0009] or

[0010] General chemical structural formula (I)

[0011] or

[0012] General chemical structural formula (II)

[0013] or

[0014] General chemical structural formula (Ⅲ)

[0015]

[0016] General chemical structural formula (Ⅳ)

[0017] In the formula: x and y are integers from 1 to 18; R1 is an aryl chain containing disulfide bonds "-Ar-SS-Ar-" (Ar is phenylene).

[0018] Furthermore, the preparation method of monomer A includes the following steps:

[0019] Step (1): Dissolve 1~1.5 mM of an aromatic disulfide containing amino or hydroxyl groups in 2~5 mL of a polar solvent;

[0020] Step (2): Add 2-4 mM of isocyanate-containing (meth)acrylate to the above solution;

[0021] Step (3): React at room temperature for 24–72 hours;

[0022] Step (4): Filter, wash, and vacuum dry at 40-80℃ for 4-10 hours to obtain monomer A.

[0023] Furthermore, crosslinking agent B is a small molecule compound containing three or more functional groups, selected from at least one of the following two classes:

[0024] (1) Thiol-containing crosslinking agents: compounds containing three or more thiol groups (-SH), such as pentaerythritol tetra(3-mercaptopropionate) (PETMP);

[0025] (2) Carbon-carbon double bond crosslinking agent: a compound containing three or more carbon-carbon double bonds, such as pentaerythritol tetraacrylate.

[0026] Furthermore, crosslinking agent B and the active end groups of monomer A form a crosslinked network through a mercapto-olefin click reaction or a free radical polymerization reaction.

[0027] Furthermore, the method for introducing the dynamically crosslinked polymer additive into a perovskite solar cell includes the following steps:

[0028] Step (1): Add monomer A and crosslinking agent B together to the perovskite precursor solution;

[0029] Step (2): Prepare perovskite thin films by spin coating and annealing processes;

[0030] Step (3): During the annealing process, monomer A and crosslinking agent B undergo a mercapto-olefin click reaction or free radical polymerization reaction, forming a dynamic crosslinked polymer additive network in situ at the perovskite grain boundary, which is anchored to the grain boundary.

[0031] Furthermore, the dynamically crosslinked polymer additive plays multiple synergistic roles in perovskite solar cells, including:

[0032] (1) Defect passivation: Strong coordinating groups such as urea / urethane groups in the polymer network can interact with Pb in the perovskite. 2+ I⁻, FA⁺ / MA⁺ form coordination bonds and hydrogen bonds, passivating intrinsic defects, regulating the crystallization process, and improving the initial photoelectric conversion efficiency.

[0033] (2) Room temperature self-healing mechanical cracks: The glass transition temperature (T) of the polymer is controlled through molecular design. g The temperature is below room temperature to ensure high fluidity of the chain segments at room temperature; the aromatic disulfide bonds in the network can undergo reversible exchange reactions at room temperature. When microcracks occur in the film, the crack surfaces come into contact under the movement of the chain segments, and the disulfide bonds exchange and recombine, achieving chemical healing and restoring the charge transport path, so that the electrical properties are restored simultaneously.

[0034] (3) Enhanced UV stability: The dense cross-linked polymer network is anchored at the grain boundary, which acts as a physical barrier to inhibit the long-range migration of halogen ions excited by UV light and to block water and oxygen erosion, thereby significantly improving the operating stability of the device under UV light.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) For the first time, a dynamic cross-linked polymer formed by in-situ polymerization of monomer A containing aromatic disulfide bonds and cross-linking agent B was applied to perovskite solar cells. Through defect passivation and crystallization promotion, the initial photoelectric conversion efficiency was significantly improved, increasing the PCE of inverted perovskite solar cells from 22.4% to over 25.1%.

[0037] (2) Rapid self-healing of mechanical cracks and restoration of electrical performance at room temperature: Rapid self-healing at room temperature without external energy input was achieved in perovskite solar cells, enabling simultaneous autonomous repair of mechanical bending cracks within ten minutes. This overcomes the limitations of existing self-healing technologies, which require external field triggering and have slow repair speeds. After 4000 cycles at a bending radius of 5 mm, the PCE retention rate of the flexible device exceeded 91%. After being left to stand at room temperature for 10 minutes, the PCE recovered to 96% of its initial value, demonstrating that electrical function was restored simultaneously with crack healing.

[0038] (3) Significantly enhanced UV stability: Under UV irradiation with an intensity of AM 1.5G 34 times, the time (T90) for the PCE of the control device to decay to 90% is less than 2 hours, while the T90 of the device of the present invention is extended to more than 13 hours. Attached Figure Description

[0039] Figure 1 A schematic diagram of an inverted perovskite solar cell device;

[0040] Figure 2 The 1H NMR spectrum of the synthesized crosslinkable monomer SS;

[0041] Figure 3 (a) is the structural formula of the disulfide bond-containing monomer SS described in Examples 1-3, (b) is the structural formula of the disulfide bond-containing monomer A2 described in Example 4, and (c) is the structural formula of the crosslinked polymer PSS described in Example 9;

[0042] Figure 4 The current density versus voltage characteristics (JV) curves of PSCs containing different concentrations of disulfide bond monomers SS in Examples 5-7 are shown.

[0043] Figure 5 The JV curve of PSCs containing 0.5 mg / mL disulfide monomer A2 in Example 8;

[0044] Figure 6 The X-ray photoelectron spectroscopy spectrum of perovskite Pb 4f in Example 9;

[0045] Figure 7 The X-ray photoelectron spectrum of perovskite N 1s in Example 9;

[0046] Figure 8 Images are taken by scanning electron microscope (SEM): (a) blank perovskite film, (b) perovskite film of Example 9;

[0047] Figure 9 The optimal JV curves for PSCs of Comparative Example 1 and Examples 9-12 containing different concentrations of disulfide monomer SS crosslinking agent PETMP are shown.

[0048] Figure 10 The images are optical micrographs of perovskite in Example 9. (a) A perovskite film containing disulfide monomer SS and crosslinking agent PETMP is damaged. (b) A perovskite film containing disulfide monomer SS and crosslinking agent PETMP undergoes self-repair of damage.

[0049] Figure 11 The optimal JV curves for PSCs containing 0.5 mg / mL disulfide monomer A2 and 0.115 mg / mL crosslinking agent PETMP in Comparative Example 1 and Example 13 are shown.

[0050] Figure 12 Normalized PCE variation curves of the devices in Comparative Example 1 and Example 9 under continuous ultraviolet light irradiation;

[0051] Figure 13 The curves show the normalized photoelectric conversion efficiency retention rate of the flexible perovskite solar cells prepared based on Comparative Example 2 and Example 14 during continuous bending tests. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to comparative examples and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0053] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0054] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0055] Comparative Example 1

[0056] Fabrication of an inverted perovskite solar cell in Comparative Example 1:

[0057] 1. Indium Tin Oxide (ITO) Conductive Glass Substrate Treatment: Clean the ITO glass by washing it sequentially with detergent, deionized (DI) water, acetone, and isopropanol (IPA). Before use, treat the ITO with a plasma cleaner for 10 minutes.

[0058] 2. Hole transport layer preparation: A 10 mg / mL nickel oxide (NiOx) solution was spin-coated onto ITO at 3000 rpm for 30 s, followed by annealing at 100 °C for 10 min. Subsequently, a 0.5 mg / mL [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (Meo-2PACz) solution was spin-coated onto ITO at 4000 rpm for 30 s, followed by annealing at 100 °C for 10 min.

[0059] 3. Preparation of the perovskite layer: Cesium iodide (CsI), methylamine iodide (MAI), formamidinium hydroiodate (FAI), and lead iodide (PbI2) were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (volume ratio DMF:DMSO = 4:1). The chemical formula is CsI. 0.05 MA 0.10 FA 0.85 A 1.6 M perovskite precursor solution was prepared using PbI3. To improve device performance, 5 mol% PbI2 was introduced. Then, 15.5 mol% methylamine hydrochloride (MACl) was added to the perovskite precursor solution and stirred overnight. 40 μL of the perovskite precursor solution was spin-coated onto Meo-2PACz at 1000 rpm for 10 s and 5000 rpm for 30 s. Seven s before the end of the last process, 300 μL of chlorobenzene (CB) was dropped onto the perovskite film as an antisolvent. The film was then annealed at 100 °C for 30 min and cooled to room temperature.

[0060] 4. Electron transport layer preparation: Spin-coating 15 mg / ml PC at 1500 rpm 61 BM's CB solution was used as an electron transport layer. The film was left at room temperature for 30 minutes to allow the film surface to dry.

[0061] 5. Preparation of cathode interface layer: BCP material was used as the cathode interface layer. BCP was dissolved in IPA at a concentration of 3 mg / mL and spin-coated at 3000 rpm for 30 s.

[0062] 6. Metal electrode: at 9×10 -4 A 100 nm silver electrode is deposited under a vacuum of Pa at a velocity of 0.2 nm / s.

[0063] 7. Device Testing: The current density versus voltage (JV) curves of the perovskite solar cell were tested using a San-Ei Electric CE solar simulator at a light intensity of 100 mW / cm². 2 The device was tested using a Keithley 2400 test setup. It had been calibrated with a certified silicon solar cell prior to testing. Measurements were performed using both reverse scan (0.02 V → -1.2 V, 0.04 V step) and forward scan (-1.2 V → 0.02 V, 0.04 V step).

[0064] The device structure of an inverted perovskite solar cell is as follows: Figure 1 As shown.

[0065] Examples 1-4 are examples of synthesizing monomer A. In Examples 1-3, the monomer A synthesized has the general formula (II), x and y are 2; R1 is an aryl chain containing disulfide bonds. Example 4 has the general formula (III), x and y are 2; R1 is an aryl chain containing disulfide bonds.

[0066] Comparative Example 2

[0067] The fabrication of the flexible inverted perovskite solar cell in Comparative Example 2 differs from that in Comparative Example 1 in the choice of substrate. A PEN substrate coated with ITO (approximately 125 μm thick) was selected.

[0068] Example 1

[0069] This embodiment is an example of monomer A containing disulfide bonds, and the synthesis method steps are as follows:

[0070] 0.8 mM bis(2-aminophenyl) disulfide was dissolved in 3 mL of dichloromethane, and 3.2 mM ethyl isocyanate acrylate was slowly added dropwise to the solution. After 24 hours, the solid formed and was filtered. The crude product was washed four times with acetonitrile. After drying under vacuum at 40 °C for 4 hours, monomer A (abbreviated as SS) containing disulfide bonds was obtained.

[0071] Example 2

[0072] This embodiment is an example of monomer A containing disulfide bonds, and the synthesis method steps are as follows:

[0073] 1.2 mM bis(2-aminophenyl) disulfide was dissolved in 3 mL of dichloromethane, and 3.2 mM ethyl isocyanate acrylate was slowly added dropwise to the solution. After 24 hours, the solid formed and was filtered. The crude product was washed four times with acetonitrile. After drying under vacuum at 40 °C for 4 hours, monomer A (abbreviated as SS) containing disulfide bonds was obtained.

[0074] The proton NMR spectrum of monomer A ( 1HNMR) such as Figure 2 As shown. 1 ¹H NMR (400 MHz, DMSO-d⁶) δ 8.14 (s, 2H), 7.90 (d, J = 8.1 Hz, 2H), 7.35 – 7.22 (m, 4H), 7.15 (t, J = 5.7 Hz, 2H), 6.91 (t, J = 7.5 Hz, 2H), 6.38 (d, J = 17.2 Hz, 2H), 6.20 (dd, J = 17.2, 10.3 Hz, 2H), 5.96 (d, J = 10.2 Hz, 2H), 4.17 (t, J = 5.5 Hz, 4H), 3.39 (q, J = 5.5 Hz, 4H). Prove its structure as follows. Figure 3 As shown in a.

[0075] Example 3

[0076] This embodiment is an example of monomer A containing disulfide bonds, and the synthesis method steps are as follows:

[0077] 1.6 mM bis(2-aminophenyl) disulfide was dissolved in 3 mL of dichloromethane, and 3.2 mM ethyl isocyanate acrylate was slowly added dropwise to the solution. After 24 hours, the solid formed and was filtered. The crude product was washed four times with acetonitrile. After drying under vacuum at 40 °C for 4 hours, monomer A (abbreviated as SS) containing disulfide bonds was obtained.

[0078] Example 4

[0079] This embodiment is an example of monomer A2 containing disulfide bonds, and the synthesis method steps are as follows:

[0080] 1.6 mM 4,4'-dihydroxydiphenyl disulfide was dissolved in 3 mL of tetrahydrofuran, and 3.2 mM isocyanate methacrylate was slowly added dropwise to the solution. After 24 hours, the solid formed and was filtered. The crude product was washed four times with acetonitrile. After vacuum drying at 40 °C for 4 hours, monomer A2 containing disulfide bonds was obtained, with the structure shown below. Figure 3 As shown in b.

[0081] Examples 5-8 below are examples of perovskite solar cell devices using only monomer A as an additive.

[0082] Example 5

[0083] This embodiment is an example of using the disulfide bond-containing monomer SS from Example 2 as a perovskite additive to prepare a solar cell device. The difference between this embodiment and Comparative Example 1 is in the preparation of the perovskite layer.

[0084] Preparation of the perovskite layer: CsI, MAI, FAI, and PbI2 were dissolved in 1 mL of a DMF:DMSO (4:1 / v:v) mixed solvent, yielding a perovskite layer with the chemical formula CsI. 0.05 MA 0.10 FA 0.85 A 1.6 M perovskite precursor solution was prepared using PbI3. To improve device performance, 5 mol% PbI2 was introduced, followed by the addition of 15.5 mol% MACl to the perovskite precursor solution. Monomer A was added, with a monomer SS concentration of 0.3 mg / mL, and the mixture was stirred overnight. 50 μL of the perovskite precursor solution was spin-coated onto Meo-2PACz at 1000 rpm for 10 s and then at 5000 rpm for 30 s. Ten s before the end of the last spin-coating, 300 μL of CB was dropped onto the perovskite film as an antisolvent. The film was then annealed at 100 °C for 30 min and cooled to room temperature.

[0085] Example 6

[0086] This embodiment is an example of using the disulfide bond-containing monomer SS from Example 2 as a perovskite additive to prepare a solar cell device. The difference between this embodiment and Comparative Example 1 is in the preparation of the perovskite layer.

[0087] Preparation of the perovskite layer: CsI, MAI, FAI, and PbI2 were dissolved in 1 mL of a DMF:DMSO (4:1 / v:v) mixed solvent, yielding a perovskite layer with the chemical formula CsI. 0.05 MA 0.10 FA 0.85 A 1.6 M perovskite precursor solution was prepared using PbI3. To improve device performance, 5 mol% PbI2 was introduced, followed by the addition of 15.5 mol% MACl to the perovskite precursor solution. Monomer A was added, with a monomer SS concentration of 0.5 mg / mL, and the mixture was stirred overnight. 50 μL of the perovskite precursor solution was spin-coated onto Meo-2PACz at 1000 rpm for 10 s and then at 5000 rpm for 30 s. Ten s before the end of the last spin-coating, 300 μL of CB was dropped onto the perovskite film as an antisolvent. The film was then annealed at 100 °C for 30 min and cooled to room temperature.

[0088] Example 7

[0089] This embodiment is an example of using the disulfide bond-containing monomer SS from Example 2 as a perovskite additive to prepare a solar cell device. The difference between this embodiment and Comparative Example 1 is in the preparation of the perovskite layer.

[0090] Preparation of the perovskite layer: CsI, MAI, FAI, and PbI2 were dissolved in 1 mL of a DMF:DMSO (4:1 / v:v) mixed solvent, yielding a perovskite layer with the chemical formula CsI. 0.05 MA 0.10 FA 0.85 A 1.6 M perovskite precursor solution was prepared using PbI3. To improve device performance, 5 mol% PbI2 was introduced, followed by the addition of 15.5 mol% MACl to the perovskite precursor solution. Monomer A was added, with a monomer SS concentration of 0.7 mg / mL, and the mixture was stirred overnight. 50 μL of the perovskite precursor solution was spin-coated onto Meo-2PACz at 1000 rpm for 10 s and then at 5000 rpm for 30 s. Ten s before the end of the last spin-coating, 300 μL of CB was dropped onto the perovskite film as an antisolvent. The film was then annealed at 100 °C for 30 min and cooled to room temperature.

[0091] The JV curve test results of the inverted perovskite solar cells in Examples 5-7 are shown below. Figure 4 When the concentration of SS is 0.3 mg / mL, a photoelectric conversion efficiency of over 23.21% can be obtained; when the concentration of SS is 0.5 mg / mL, a photoelectric conversion efficiency of over 23.65% can be obtained; and when the concentration of SS is 0.7 mg / mL, a photoelectric conversion efficiency of over 23.48% can be obtained. Therefore, the photoelectric conversion efficiency is optimal when the concentration of SS is 0.5 mg / mL.

[0092] Example 8

[0093] This embodiment is an example of using the disulfide-bonded monomer A2 from Example 4 as a perovskite additive to prepare a solar cell device. The difference between this embodiment and Comparative Example 1 is in the preparation of the perovskite layer.

[0094] Preparation of the perovskite layer: CsI, MAI, FAI, and PbI2 were dissolved in 1 mL of a DMF:DMSO (4:1 / v:v) mixed solvent, yielding a perovskite layer with the chemical formula CsI. 0.05 MA 0.10 FA 0.85A 1.6 M perovskite precursor solution was prepared using PbI3. To improve device performance, 5 mol% PbI2 was introduced, followed by the addition of 15.5 mol% MACl to the perovskite precursor solution. Monomer A2 (0.5 mg / mL) was then added, and the mixture was stirred overnight. 50 μL of the perovskite precursor solution was spin-coated onto Meo-2PACz at 1000 rpm for 10 s and then at 5000 rpm for 30 s. Ten s before the end of the last spin-coating, 300 μL of LCB was dropped onto the perovskite film as an antisolvent. The film was then annealed at 100 °C for 30 min and cooled to room temperature.

[0095] The JV curve test results of the inverted perovskite solar cell in Example 8 are shown below. Figure 5 It can achieve a photoelectric conversion efficiency of over 22.16%.

[0096] Examples 9-13 below are examples of perovskite solar cell devices using monomer A and crosslinking agent B as additives.

[0097] Example 9

[0098] This embodiment describes the application of an in-situ crosslinked polymer in the fabrication of an inverted perovskite solar cell, specifically by simultaneously adding monomer A and crosslinking agent B. The monomer SS, containing disulfide bonds, is used as the crosslinking agent in Example 2, and pentaerythritol (PETMP) ester (3-mercaptopropionic acid) is selected as crosslinking agent B. This embodiment demonstrates the in-situ crosslinking of SS and PETMP as perovskite additives to fabricate a solar cell device. The difference between this embodiment and Comparative Example 1 lies in the preparation of the perovskite layer.

[0099] Preparation of the perovskite layer: CsI, MAI, FAI, and PbI2 were dissolved in 1 mL of a DMF:DMSO (4:1 / v:v) mixed solvent, yielding a perovskite layer with the chemical formula CsI. 0.05 MA 0.10 FA 0.85 A 1.6 M perovskite precursor solution was prepared using PbI3. To improve device performance, 5 mol% PbI2 was introduced, followed by the addition of 15.5 mol% MACl to the perovskite precursor solution. SS and pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP) were then added, with SS concentrations of 0.5 mg / mL and PETMP concentrations of 0.115 mg / mL, and the mixture was stirred overnight. 50 μL of the perovskite precursor solution was spin-coated onto Meo-2PACz at 1000 rpm for 10 s and 5000 rpm for 30 s. Ten s before the end of the last spin-coating, 300 μL of CB was dropped onto the perovskite film as an antisolvent. The film was then annealed at 100 °C for 30 min and cooled to room temperature.

[0100] like Figure 6 The X-ray photoelectron spectroscopy (XPS) spectrum of Pb 4f is shown. After introducing the SS additive, in-situ crosslinking forms the polymer PSS, the structural formula of which is shown below. Figure 3 As shown in c. Pb 4f in the PSS-modified perovskite film. 5 / 2 and Pb 4f 7 / 2 The binding energies of Pb all shift towards lower energies. This phenomenon indicates that the functional groups in the PSS molecule provide lone pairs of electrons, which can bind with Pb. 2+ Ions form coordinate bonds, leading to an increase in the electron density around lead. For example... Figure 7 The image shows the X-ray photoelectron spectroscopy (XPS) spectrum of the N 1s peak. The N 1s peak also shows a shift towards lower binding energies, confirming the hydrogen bonding interaction between PSS and the formamidinium (FA) / methylamine (MA) cations in the perovskite. PSS forms multiple synergistic effects with the perovskite components through its functional groups, including robust coordination bonds and hydrogen bonds, effectively passivating film defects.

[0101] like Figure 8 As shown, the modified perovskite film of this embodiment exhibits significantly larger and more uniform grains. This indicates that the addition of SS and the crosslinking agent PETMP causes SS to crosslink, effectively promoting the growth of perovskite grains.

[0102] Example 10

[0103] The difference between this embodiment and Embodiment 9 lies in the preparation of the perovskite layer.

[0104] Preparation of the perovskite layer: CsI, MAI, FAI, and PbI2 were dissolved in 1 mL of a DMF:DMSO (4:1 / v:v) mixed solvent, yielding a perovskite layer with the chemical formula CsI. 0.05 MA 0.10 FA 0.85 A 1.6 M perovskite precursor solution was prepared using PbI3. To improve device performance, 5 mol% PbI2 was introduced, followed by the addition of 15.5 mol% MACl to the perovskite precursor solution. SS and PETMP were then added, with SS concentrations of 0.3 mg / mL and PETMP concentrations of 0.069 mg / mL, and the mixture was stirred overnight. 50 μL of the perovskite precursor solution was spin-coated onto Meo-2PACz at 1000 rpm for 10 s and 5000 rpm for 30 s. Ten s before the end of the last spin-coating, 300 μL of CB was dropped onto the perovskite film as an antisolvent. The film was then annealed at 100 °C for 30 min and cooled to room temperature.

[0105] Example 11

[0106] The difference between this embodiment and Embodiment 9 lies in the preparation of the perovskite layer.

[0107] Preparation of the perovskite layer: CsI, MAI, FAI, and PbI2 were dissolved in 1 mL of a DMF:DMSO (4:1 / v:v) mixed solvent, yielding a perovskite layer with the chemical formula CsI. 0.05 MA 0.10 FA 0.85 A 1.6 M perovskite precursor solution was prepared using PbI3. To improve device performance, 5 mol% PbI2 was introduced, followed by the addition of 15.5 mol% MACl to the perovskite precursor solution. SS and PETMP were then added, with SS concentrations of 0.7 mg / mL and PETMP concentrations of 0.161 mg / mL, and the mixture was stirred overnight. 50 μL of the perovskite precursor solution was spin-coated onto Meo-2PACz at 1000 rpm for 10 s and 5000 rpm for 30 s. Ten s before the end of the last spin-coating, 300 μL of CB was dropped onto the perovskite film as an antisolvent. The film was then annealed at 100 °C for 30 min and cooled to room temperature.

[0108] Example 12

[0109] The difference between this embodiment and Embodiment 9 lies in the preparation of the perovskite layer.

[0110] Preparation of the perovskite layer: CsI, MAI, FAI, and PbI2 were dissolved in 1 mL of a DMF:DMSO (4:1 / v:v) mixed solvent, yielding a perovskite layer with the chemical formula CsI. 0.05 MA 0.10 FA 0.85 A 1.6 M perovskite precursor solution was prepared using PbI3. To improve device performance, 5 mol% PbI2 was introduced, followed by the addition of 15.5 mol% MACl to the perovskite precursor solution. SS and PETMP were then added, with SS concentrations of 0.9 mg / mL and PETMP concentrations of 0.207 mg / mL, and the mixture was stirred overnight. 50 μL of the perovskite precursor solution was spin-coated onto Meo-2PACz at 1000 rpm for 10 s and 5000 rpm for 30 s. Ten s before the end of the last spin-coating, 300 μL of CB was dropped onto the perovskite film as an antisolvent. The film was then annealed at 100 °C for 30 min and cooled to room temperature.

[0111] The test results of the current density and voltage characteristic curves (JV curves) of the inverted PSC in Examples 9-12 and Comparative Example 1 are shown in the figure. Figure 9 .

[0112] The PCE of the inverted PSC in Comparative Example 1 is 22.41%, and the short-circuit current density (Jsc) is 25.98 mA / cm². 2 The open-circuit voltage (Voc) is 1.091 V, and the fill factor (FF) is 79.06%. The PCE of the inverted PSC in Example 9 is 25.10%, and the Jsc is 26.33 mA / cm². 2 The Voc was 1.116V, and the FF was 85.44%. The PCE of the inverted PSC in Example 10 was 23.90%, and the Jsc was 25.78 mA / cm². 2 The Voc was 1.102V, and the FF was 84.12%. The PCE of the inverted PSC in Example 11 was 23.53%, and the Jsc was 26.17 mA / cm². 2 The Voc was 1.083V, and the FF was 83.01%. The PCE of the inverted PSC in Example 12 was 23.30%, and the Jsc was 26.12 mA / cm². 2 The Voc value is 1.101V and the FF value is 81.02%.

[0113] The improvement in PCE is mainly due to the increase in Voc and the significant improvement in FF, which is likely related to the improved quality of perovskite films and trap passivation after the introduction of SS additives.

[0114] Compared to the device performance of Comparative Example 1, the device efficiency was optimal when the concentration of SS additive was 0.5 mg / mL. The self-healing behavior of the perovskite film at the optimal doping concentration was observed, such as... Figure 10 As shown, the perovskite film was damaged and scratched, but the scratches disappeared after 10 minutes at room temperature, demonstrating the self-healing properties of the perovskite film.

[0115] Example 13

[0116] The difference between this embodiment and Embodiment 9 lies in the preparation of the perovskite layer.

[0117] Preparation of the perovskite layer: CsI, MAI, FAI, and PbI2 were dissolved in 1 mL of a DMF:DMSO (4:1 / v:v) mixed solvent, yielding a perovskite layer with the chemical formula CsI. 0.05 MA 0.10 FA 0.85A 1.6 M perovskite precursor solution was prepared using PbI3. To improve device performance, 5 mol% PbI2 was introduced, followed by the addition of 15.5 mol% MACl to the perovskite precursor solution. SS and PETMP were then added, with A2 concentrations of 0.5 mg / mL and PETMP concentrations of 0.115 mg / mL, and the mixture was stirred overnight. 50 μL of the perovskite precursor solution was spin-coated onto Meo-2PACz at 1000 rpm for 10 s and 5000 rpm for 30 s. Ten s before the end of the last spin-coating, 300 μL of CB was dropped onto the perovskite film as an antisolvent. The film was then annealed at 100 °C for 30 min and cooled to room temperature.

[0118] The test results of the current density and voltage characteristic curves (JV curves) of the inverted PSC in Example 13 and Comparative Example 1 are shown below. Figure 11 It can be seen that the PCE of the inverted PSC in Comparative Example 1 is 22.41%, and the Jsc is 25.98 mA / cm². 2 The Voc was 1.091 V, and the FF was 79.06%. The PCE of the inverted PSC in Example 13 was 22.67%, and the Jsc was 24.89 mA / cm². 2 The Voc is 1.1V and the FF is 82.79%, indicating improved device performance.

[0119] Comparing the device performance of all examples with Comparative Example 1, the device efficiency was optimal (i.e., Example 9 was optimal) when the concentration of monomeric SS additive was 0.5 mg / mL and crosslinking agent B was added. Furthermore, the photoelectric conversion efficiency with crosslinking agent B at the same SS concentration was superior to that without B. The perovskite solar cell with the optimal doping concentration in Example 9 was placed in air, and 365 nm ultraviolet light was incident from the glass side, with a total dose of 157 mW / cm². 2 It is approximately 34 times the intensity of sunlight at AM 1.5 G. Under high-intensity ultraviolet radiation, the device in Comparative Example 1 decays rapidly (T90 < 2 hours), while the target device retains 90% of its initial PCE within 13 hours (see...). Figure 12 ).

[0120] Example 14

[0121] The difference between this embodiment and Embodiment 9 lies in the choice of substrate. A PEN substrate coated with ITO (approximately 125 μm thick) was used to fabricate a perovskite solar cell with the optimal SS doping concentration. In a mechanical bending test with a radius of 5 mm (see...),... Figure 13After 4,000 bending cycles, the device of Example 14 retained more than 91% of its initial PCE, while that of Comparative Example 2 degraded to 83%. Surprisingly, the device of Example 14 recovered to 96% of its original efficiency after 10 minutes at room temperature, demonstrating repeatable self-healing behavior and excellent mechanical sustainability.

Claims

1. A monomer A containing an aromatic disulfide bond, a urea / urethane group, and a vinyl group, characterized in that, The monomer A has the structure shown in general formulas (Ⅰ), (Ⅱ), (Ⅲ) or (Ⅳ): or General chemical structural formula (I) or General chemical structural formula (II) or General chemical structural formula (Ⅲ) General chemical structural formula (Ⅳ) In the formula: x and y are integers from 1 to 18; R1 is an aryl chain containing disulfide bonds, with the structure "-Ar-SS-Ar-" (Ar is phenylene).

2. A dynamically crosslinked polymer additive, characterized in that, The additive is a cross-linked polymer formed by reacting monomer A as described in claim 1 with cross-linking agent B.

3. The dynamic crosslinking polymer additive according to claim 2, characterized in that, The crosslinking agent B is a small molecule compound containing three or more functional groups, wherein the functional groups are selected from thiol groups or carbon-carbon double bonds.

4. The dynamic crosslinking polymer additive according to claim 3, characterized in that, The crosslinking agent B is a thiol-containing crosslinking agent selected from pentaerythritol tetra(3-mercaptopropionate).

5. The dynamic crosslinking polymer additive according to claim 3, characterized in that, The crosslinking agent B is a carbon-carbon double bond crosslinking agent selected from pentaerythritol tetraacrylate.

6. A method for preparing monomer A as shown in general formula (I) or (II) of claim 1, characterized in that, Includes the following steps: Dissolve 1-1.5 mM of an aromatic compound containing an amino group and a disulfide bond in 2-5 mL of a polar solvent, and add 2-4 mM of a molecule containing an isocyanate group and a vinyl group dropwise to the above solution; after the reaction, filter, wash the obtained solid, and dry it under vacuum to obtain monomer A.

7. A method for preparing monomer A as shown in general formula (III) or (IV) of claim 1, characterized in that, The process includes the following steps: dissolving 1-1.5 mM of an aromatic compound containing hydroxyl groups and disulfide bonds in 2-5 mL of a polar solvent; adding dropwise a compound containing isocyanate groups and vinyl groups to the resulting solution; filtering after the reaction; washing and vacuum drying the resulting solid to obtain monomer A.

8. The preparation method according to claim 6 or 7, characterized in that, The reaction is carried out at room temperature for 24 to 72 hours, and the vacuum drying conditions are vacuum drying at 40 to 80°C for 4 to 10 hours.

9. The preparation method according to claim 6 or 7, characterized in that, The polar solvent is tetrahydrofuran, n-butanol, ethyl acetate, diethyl ether, dichloromethane, chloroform, or toluene.

10. The method for preparing the dynamic crosslinking polymer additive according to any one of claims 2 to 5, characterized in that, The crosslinking agent B and the active end group of the monomer A form a crosslinking network through a mercapto-olefin click reaction or a free radical polymerization reaction; the reaction is carried out in situ during the annealing process of the perovskite layer of the perovskite solar cell.

11. A perovskite layer for a solar cell, characterized in that, The perovskite layer contains a cross-linked network formed by the dynamic cross-linked polymer additive as described in any one of claims 2 to 5.

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