A method for improving the service life of a perovskite device based on a two-dimensional polymer ion locking strategy, a perovskite film and a perovskite device

Abstract

This invention provides a method, a perovskite thin film, and a perovskite device for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy, comprising the following steps: S1: dispersing a two-dimensional polymer in a solvent to obtain a two-dimensional polymer precursor solution; S2: coating the two-dimensional polymer precursor solution onto the surface of a perovskite layer to form a two-dimensional polymer thin film, wherein the two-dimensional polymer contains a triazine ring structure, and the triazine ring structure is related to Pb in the perovskite. 2+ Coordination and chelation occur to form a barrier layer that inhibits ion migration, which can simultaneously and effectively inhibit A-site organic cations (FA). + MA + The volatilization of ) and halide anions (I) ‑ The cross-interface migration of ions solves the problem of thermal decomposition of perovskite materials caused by ion migration, significantly improving the lifespan of perovskite devices under thermal stress. It can work stably for more than 1,000 hours under harsh conditions of 100°C, demonstrating excellent high-temperature thermal stability.

Description

Technical Field

[0001] This invention relates to the technical field of perovskite devices, specifically to a method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy, perovskite thin films, and perovskite devices. Background Technology

[0002] Organic-inorganic hybrid perovskite solar cells, with their strong light-harvesting ability, ultra-long carrier diffusion length, and light weight, are expected to become a complete replacement for silicon-based solar cells. Since 2009, the power conversion efficiency of perovskite solar cells has increased from 3.8% to over 27.0%, nearly on par with silicon-based solar cells. However, despite the excellent photoelectric performance and low manufacturing cost of perovskite solar cells, their poor operational stability remains a serious obstacle to their commercialization. Perovskite is an intrinsic ionic semiconductor, and its ion migration kinetics follow an Arrhenius-type dependence, leading to an exponential increase in mobility at high temperatures. Although adaptive ion migration within the bulk phase can promote charge extraction, cross-interface migration can severely impair the performance of perovskite devices. Once ions cross the interface, defects are generated and perovskite decomposition is triggered, resulting in irreversible performance loss. Therefore, during the operation of perovskite devices, if halide anions and A-site organic cations can be confined within the light-absorbing layer, lattice integrity can be maintained while improving device efficiency.

[0003] To date, limitations on iodine ion migration have primarily focused on reducing migration channels rather than fundamentally blocking them. In fact, numerous diffuse ion migration channels exist within and at the interfaces of perovskites. Simply reducing the number of channels is insufficient to effectively suppress long-range ion migration under thermal stress or electric fields, and it cannot prevent the volatilization of A-site organic cations. Therefore, developing a method to improve the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy is of great significance. Summary of the Invention

[0004] This invention is made to solve the above-mentioned problems, and aims to provide a method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy, as well as perovskite thin films and perovskite devices.

[0005] This invention provides a method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy, characterized by the following steps: S1: dispersing a two-dimensional polymer in a solvent to obtain a two-dimensional polymer precursor solution; S2: coating the two-dimensional polymer precursor solution onto the surface of a perovskite layer to form a two-dimensional polymer film, wherein the two-dimensional polymer contains a triazine ring structure, and the triazine ring structure is related to Pb in the perovskite. 2+ Coordination and chelation occur to form a barrier layer that inhibits ion migration.

[0006] The method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy provided by the present invention may also have the following feature: wherein the two-dimensional polymer is 2DPA or a derivative thereof.

[0007] The method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy provided by the present invention may also have the following feature: wherein the solvent is one or a mixture of isopropanol, chlorobenzene, and N,N-dimethylformamide, and the dispersion step includes stirring at 20~30°C for 6~48 h.

[0008] The method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy provided by the present invention may also have the following feature: wherein the material of the perovskite layer is ABX3 organic-inorganic perovskite.

[0009] The method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy provided by the present invention may also have the following features: wherein the coating method is spin coating, blade coating or slot coating, and when the coating method is spin coating, the rotation speed is 3000~6000 rpm and the spin coating time is 50~150 s.

[0010] The present invention also provides a perovskite thin film, which is prepared by a method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy, and has the following features: a perovskite layer and a two-dimensional polymer layer disposed on at least one surface of the perovskite layer.

[0011] The present invention also provides a perovskite device having the feature of including a perovskite thin film.

[0012] The perovskite device provided by the present invention may also have the following features: wherein the perovskite device is a solar cell, comprising a substrate and, in a direction away from the substrate, the following layers are sequentially arranged: a hole transport layer, a perovskite layer, a two-dimensional polymer layer, an electron transport layer, a hole blocking layer, and a metal electrode layer.

[0013] The perovskite device provided by this invention may also have the following characteristics: the substrate material is FTO conductive glass, ITO conductive glass, glass, quartz, or silicon; the hole transport layer material is 2PACz, Me-2PACz, 4PACz, or Me-4PACz; the preparation method is as follows: dissolving the hole transport layer material in an alcohol solvent to obtain a hole transport layer solution; coating the hole transport layer solution onto a substrate; and annealing to obtain the hole transport layer; the alcohol solvent is one or a mixture of two of ethanol and isopropanol; and the electron transport layer material is PC. 61BM or C60. When the electron transport layer material is C60, the preparation method is as follows: using vapor deposition, with C60 as the evaporation source, an electron transport layer is formed on the two-dimensional polymer layer. The hole blocking layer material is BCP, PEI, or SnO2. When the hole blocking layer material is BCP, the preparation method is as follows: using vapor deposition, with BCP as the evaporation source, a hole blocking layer is formed on the electron transport layer. The metal electrode layer material is Ag, Au, or Cu. The preparation method is as follows: using vapor deposition, with the material of the metal electrode layer as the evaporation source, a metal electrode layer is formed on the hole blocking layer.

[0014] The perovskite device provided by this invention may also have the following features: wherein the perovskite device is a light-emitting diode, a laser, a photodetector, or a field-effect transistor.

[0015] The role and effect of invention

[0016] The method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy, the perovskite thin film, and the perovskite device according to the present invention have the following beneficial effects:

[0017] This invention utilizes a two-dimensional polymer (two-dimensional polymer layer) containing a triazine ring structure formed on the surface of a perovskite layer, and leverages the triazine ring with Pb 2+ NH...I between - Coordination and cyclic chelation create a dense, impermeable ion-barrier layer at the molecular scale. This barrier layer effectively inhibits A-site organic cations (FA). + MA + The volatilization of ) and halide anions (I) - The cross-interface migration of ions solves the problem of thermal decomposition of perovskite materials caused by ion migration, significantly improving the lifespan of perovskite devices under thermal stress. It can work stably for more than 1,000 hours under harsh conditions of 100°C, demonstrating excellent high-temperature thermal stability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a two-dimensional polymer in an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the perovskite device in an embodiment of the present invention.

[0020] Figure 3 The graph shows the change of PL intensity over time at different temperatures for the perovskite thin film in Test Example 1 of this invention and the pure perovskite thin film in the comparative example.

[0021] Figure 4 The images show the surface KPFM patterns of the perovskite film in Test Example 2 of the present invention and the pure perovskite film in the comparative example.

[0022] Figure 5 The images show SEM images of the perovskite film in Test Example 3 of the present invention and the pure perovskite film in the comparative example before and after aging.

[0023] Figure 6 The JV curves are shown for the perovskite device in Test Example 4 of the present invention and the pure perovskite device in the comparative example.

[0024] Figure 7 The MPPT images are of the perovskite device in the fifth test example of the present invention and the pure perovskite device in the comparative example.

[0025] Figure 8 The thermal stability diagrams are shown for the perovskite device in Test Example 6 of the present invention and the pure perovskite device in the comparative example.

[0026] Explanation of symbols for main components:

[0027] In the figure: 100, perovskite device; 1, substrate; 2, hole transport layer; 3, perovskite layer; 4, two-dimensional polymer layer; 5, electron transport layer; 6, hole blocking layer; 7, metal electrode layer. Detailed Implementation

[0028] To facilitate understanding of the technical means, inventive features, objectives, and effects of this invention, the following embodiments, in conjunction with the accompanying drawings, provide a detailed description of a method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy, as well as the perovskite thin film and the perovskite device. In the following embodiments, reagents and materials not explicitly stated were obtained through common commercial channels, and experimental operations and conditions not described were performed in accordance with conventional practices and conditions in the art.

[0029] Example

[0030] This embodiment provides a method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy, including the following steps:

[0031] S1: The two-dimensional polymer is dispersed in a solvent to obtain a two-dimensional polymer precursor solution. The specific operation steps are as follows:

[0032] The two-dimensional polymer is added to a solvent and dispersed by stirring at 25 °C for 6 to 48 h to obtain a two-dimensional polymer precursor solution. The concentration of the two-dimensional polymer in the two-dimensional polymer precursor solution is 0.1 to 5.0 mg / mL, preferably 0.2 mg / mL.

[0033] The solvent is one or a mixture of isopropanol (IPA), chlorobenzene (CB), and N,N-dimethylformamide (DMF).

[0034] Figure 1 This is a schematic diagram of the structure of a two-dimensional polymer in an embodiment of the present invention.

[0035] like Figure 1 As shown, the two-dimensional polymer is 2DPA or a derivative thereof. The two-dimensional polymer contains a triazine ring structure, which is similar to Pb in perovskite. 2+ NH...I is generated between them - Coordination and cyclic chelation. This dual action forms an extremely dense and impermeable barrier layer at the molecular scale, simultaneously preventing FA from... + / MA + It volatilizes and inhibits the migration of iodide ions.

[0036] S2: Coat the surface of the perovskite layer with a two-dimensional polymer precursor solution to form a two-dimensional polymer film.

[0037] The material of the perovskite layer is ABX3 organic-inorganic perovskite.

[0038] The coating method can be spin coating, blade coating, or slot coating. In this embodiment, a two-dimensional polymer precursor solution is spin-coated onto the surface of the perovskite layer to form a two-dimensional polymer film with a nanometer-thickness. The spin coating speed is 3000~6000 rpm and the spin coating time is 50~150 s.

[0039] This embodiment also provides a perovskite thin film, which is prepared by the aforementioned method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy, and includes a perovskite layer and a two-dimensional polymer layer disposed on at least one surface of the perovskite layer.

[0040] Figure 2 This is a schematic diagram of the structure of the perovskite device 100 in an embodiment of the present invention.

[0041] like Figure 2 As shown, this embodiment also provides a perovskite device 100, which can be a solar cell, a light-emitting diode, a laser, a photodetector, or a field-effect transistor. These perovskite devices 100 all include the aforementioned perovskite thin film, thus significantly improving their stability.

[0042] When the perovskite device 100 is a solar cell, it includes a substrate 1 and a hole transport layer 2, a perovskite layer 3, a two-dimensional polymer layer 4, an electron transport layer 5, a hole blocking layer 6, and a metal electrode layer 7 arranged sequentially in a direction away from the substrate 1, and the above-mentioned parts are prepared sequentially.

[0043] The substrate 1 is made of FTO conductive glass, ITO conductive glass, glass, quartz, or silicon. In this embodiment, substrate 1 is ITO conductive glass (1.5 cm x 1.5 cm). The preparation method of substrate 1 is as follows: the ITO conductive glass is sequentially cleaned with deionized water, acetone, alcohol, and deionized water for 60 min each (i.e., each cleaning process is 60 min). The cleaned ITO conductive glass is dried using a bulb syringe and nitrogen or argon gas, then placed in a plasma cleaner (model DIENER PLASMA ATTO) for 30 min, and then dried again using nitrogen or argon gas for later use.

[0044] The hole transport layer 2 is made of 2PACz, Me-2PACz, 4PACz, or Me-4PACz. The preparation method is as follows: the material of the hole transport layer 2 is dissolved in an alcohol solvent, and the mixture is stirred to obtain a hole transport layer solution. The hole transport layer solution is coated onto one side surface of the substrate 1, and after annealing, the hole transport layer 2 is obtained.

[0045] Specifically, the concentrations of 2PACz, Me-2PACz, 4PACz, or Me-4PACz are all 0.1-2.0 mg / mL. The alcohol solvent is one or a mixture of two of ethanol and isopropanol. The coating method can be spin coating, blade coating, slot coating, etc. The annealing temperature is 110 ℃ and the time is 8 min.

[0046] The perovskite layer 3 was prepared as follows: Lead iodide, cesium iodide, formamidine iodide, methylamine chloride, and methylamine iodide were dissolved in 1 mL of a mixed solvent of DMF and DMSO. The solution was stirred at 25 °C for 24 h to dissolve the materials, and then allowed to stand to obtain a perovskite solution. 200 μL of the perovskite solution was taken and coated onto the side of the hole transport layer 2 away from the substrate 1. Then, it was spin-coated at 1000 rpm for 15 s, followed by spin-coating at 5000 rpm for 80 s. After spin-coating, the layer was heated at 90 °C for 10 min to remove the mixed solvent of DMF and DMSO, thus obtaining the perovskite layer 3.

[0047] The two-dimensional polymer layer 4 is prepared as follows: the two-dimensional polymer is dispersed in 1 mL of IPA, DMF or CB, and stirred at 25°C for 24 h to ensure complete dispersion, thus obtaining a two-dimensional polymer precursor solution. 200 μL of the two-dimensional polymer precursor solution is spin-coated onto the surface of the perovskite layer 3 away from the hole transport layer 2. The spin-coating speed is 5000 rpm and the spin-coating time is 120 s, forming the two-dimensional polymer layer 4, i.e., the two-dimensional polymer film.

[0048] The material of electron transport layer 5 is PC. 61BM or C60. When the electron transport layer 5 is made of C60, the fabrication method is as follows: using vapor deposition, the perovskite device 100 with the two-dimensional polymer layer 4 already prepared is placed in a vapor deposition machine, a mask is placed, and the vacuum degree of the vapor deposition machine is evaporated to 1 x 10⁻⁶. -5 Below Pa. Using C60 as the evaporation source, vapor deposition was performed at a current of 2~8 mA, with a deposition thickness of 20-40 nm, forming an electron transport layer 5 on the surface of the two-dimensional polymer layer 4 away from the perovskite layer 3.

[0049] The hole blocking layer 6 is made of BCP, PEI, or SnO2. When the hole blocking layer 6 is made of BCP, the preparation method is as follows: using the same vapor deposition method as described above, BCP is used as the evaporation source, and vapor deposition is performed at a current of 1-5 mA. The vapor deposition thickness is 2-12 nm, and the hole blocking layer 6 is formed on the side of the electron transport layer 5 away from the two-dimensional polymer layer 4.

[0050] The metal electrode layer 7 is made of Ag, Au, or Cu. It can be prepared by vapor deposition, magnetron sputtering, chemical vapor deposition, or physical vapor deposition. When vapor deposition is used: Ag, Au, or Cu is used as the evaporation source, and vapor deposition is performed at a current of 10–15 mA to achieve a thickness of 80–200 nm, forming the metal electrode layer 7 on the surface of the hole blocking layer 6 away from the electron transport layer 5.

[0051] Specifically, when the material of the metal electrode layer 7 is Ag, the evaporation thickness is preferably 90~110 nm. In practical applications, if it is necessary to prepare an array of metal electrode layers 7 on the surface of the hole blocking layer 6, a mask corresponding to the array is placed on the surface of the hole blocking layer 6, and then placed in an evaporation machine for evaporation to obtain the array of metal electrode layers 7.

[0052] For other types of perovskite devices 100, such as light-emitting diodes, lasers, photodetectors, or field-effect transistors, their fabrication methods can refer to the fabrication process of solar cells described above. Only the materials of each layer and the corresponding processes need to be adapted according to the functional requirements of the device, which will not be elaborated here.

[0053] Comparative Example

[0054] This comparative example provides a pure perovskite thin film without the two-dimensional polymer layer 4, and a pure perovskite device containing the pure perovskite thin film. The difference between this comparative example and the embodiment is that the preparation step of the two-dimensional polymer layer 4 is omitted, so the pure perovskite device does not contain the two-dimensional polymer layer 4. The remaining preparation processes are the same as those in the embodiment.

[0055] Test Example 1

[0056] In this test example, the perovskite thin film of the embodiment and the pure perovskite thin film of the comparative example were subjected to PL tests at different temperatures (120 °C, 135 °C, 150 °C) to examine the change of PL intensity of the two over time (excitation wavelength of 365 nm).

[0057] Figure 3 This is a graph showing the change in PL intensity over time at different temperatures for the perovskite thin film of the embodiment and the pure perovskite thin film of the comparative example in Test Example 1 of this invention. Wherein, control is the PL spectrum of the pure perovskite thin film of the comparative example over time; 2DPA is the PL spectrum of the perovskite thin film of the embodiment over time.

[0058] Test results are as follows Figure 3 As shown, the photoluminescence intensity (PL) of the pure perovskite film in the comparative example decreases significantly over time under excitation light, while the photoluminescence intensity of the perovskite film in the examples remains almost constant under excitation light. This rapid decrease in intensity indicates the rapid decomposition of the perovskite phase, with the extremely high temperature corresponding to the A-site organic cation (such as FA). + MA + The volatilization of ions provides sufficient activation energy and lowers the energy barrier for ion migration. However, the perovskite film protected by 2DPA did not undergo significant decomposition, indicating that the two-dimensional polymer layer 4 can effectively suppress the volatilization of A-site organic cations and the migration of iodide ions, thereby significantly improving the stability of perovskite under thermal stress.

[0059] Test Example 2

[0060] This test example uses Kelvin probe force microscopy (KPFM) to test the perovskite thin film of the embodiment and the pure perovskite thin film of the comparative example to examine the surface potential distribution of both.

[0061] Figure 4 The images show the surface KPFM patterns of the perovskite film in Test Example 2 of the present invention and the pure perovskite film in the comparative example. Perovskite is the pure perovskite film in the comparative example, and W / 2DPA is the perovskite film in the example.

[0062] Test results are as follows Figure 4 As shown, the surface potential distribution of the pure perovskite film in the comparative example ranges from 266.6 to 613.3 mV, while that of the perovskite film in the embodiment ranges from -343.3 to -113.9 mV. The significant decrease in surface potential indicates that the 2DPA layer induces the formation of favorable interfacial dipoles, thereby effectively reducing the work function of the perovskite surface. Therefore, this improved interfacial carrier management directly promotes the suppression of interfacial recombination, which is closely related to the improvement in open-circuit voltage and fill factor in the performance of the perovskite device 100.

[0063] Test Example 3

[0064] In this test case, SEM tests were performed on the perovskite film of the embodiment and the pure perovskite film of the comparative example before and after aging (85 °C, 10 days) to examine the changes in surface morphology of the two.

[0065] Figure 5 The images show SEM images of the perovskite film in Test Example 3 of the present invention and the pure perovskite film in the comparative example before and after aging. Perovskite is the pure perovskite film in the comparative example; Perovskite / 2DPA is the perovskite film in the example.

[0066] Test results are as follows Figure 5 As shown, before aging, the pure perovskite film in the comparative example and the perovskite film in the embodiment exhibited similar surface morphology. After 10 days of thermal aging, a large amount of PbI2 was observed in the SEM image of the perovskite film in the comparative example, which is a typical thermal decomposition product of perovskite. In contrast, no obvious PbI2 formation was observed in the perovskite film of the embodiment under the same aging conditions, indicating that its thermal decomposition was effectively suppressed. Therefore, 2DPA significantly improves the thermal stability of the perovskite film.

[0067] Test Example 4

[0068] This test example performs JV curve tests on the perovskite device 100 of the embodiment and the pure perovskite device of the comparative example to examine their photoelectric conversion performance. The JV curve tests were conducted using a light source intensity of 1.5 AM.

[0069] Figure 6 The JV curves are shown for the perovskite device 100 in Test Example 4 of the present invention and the pure perovskite device in the comparative example. Figure 6 In the diagram, Control is a pure perovskite device for comparison, and W / 2DPA is the perovskite device 100 of the embodiment.

[0070] Test results are as follows Figure 6 As shown, the pure perovskite device in the comparative example exhibits a photoelectric conversion efficiency of 25.13%, a short-circuit current density of 26.25 mA cm⁻², an open-circuit voltage of 1.133 V, and a fill factor of 84.49%. The perovskite device 100 in the embodiment shows significantly improved performance, with a photoelectric conversion efficiency increased to 25.77%, a short-circuit current density increased to 26.29 mA cm⁻², an open-circuit voltage of 1.148 V, and a fill factor of 85.38%. The simultaneous improvement in open-circuit voltage and fill factor is highly correlated with the aforementioned KPFM results. The two-dimensional polymer effectively passivates surface defects and optimizes the interfacial energy arrangement, thereby suppressing nonradiative recombination and promoting efficient charge extraction.

[0071] Test Example 5

[0072] This test case performs maximum power point tracking tests on the perovskite device 100 of the embodiment and the pure perovskite device of the comparative example to examine their operational stability.

[0073] The test conditions were: a nitrogen atmosphere, using an AM 1.5G white light-emitting diode as the light source.

[0074] Figure 7 The MPPT images are of the perovskite device in the fifth test example of the present invention and the pure perovskite device in the comparative example.

[0075] Test results are as follows Figure 7 As shown, the photoelectric conversion efficiency of the comparative example decays rapidly. However, the perovskite device 100 of the embodiment can still maintain 90.1% of its initial efficiency after about 1000 hours, showing significantly better operational stability.

[0076] Test Example 6

[0077] In this test case, the thermal stability of the perovskite device 100 of the embodiment and the pure perovskite device of the comparative example were tested under high temperature conditions of 85 °C and 100 °C to examine the change of photoelectric conversion efficiency of the two with aging time.

[0078] Figure 8 The thermal stability diagrams are shown for the perovskite device in Test Example 6 of the present invention and the pure perovskite device in the comparative example.

[0079] Test results are as follows Figure 8 As shown, after aging at 85°C for 1152 hours, the perovskite device 100 of the embodiment retained 88.4% of its original photoelectric conversion efficiency, while the comparative pure perovskite device, under the same conditions, rapidly degraded to 61.2% of its initial performance in just the first 24 hours. At 100°C, the perovskite device 100 of the embodiment retained 81.0% of its original photoelectric conversion efficiency for 1020 hours. The comparative pure perovskite device, however, rapidly degraded to 25.4% of its initial photoelectric conversion efficiency in just the first 24 hours, indicating that thermal stress caused severe erosion. At high temperatures, the FA within the perovskite... + and MA + Tendency to spontaneously seek escape routes, I - Under the combined influence of heat and internal electric field, the material rapidly migrates towards the silver electrode, causing a sharp decline in the efficiency of perovskite solar cells. In this application, however, the two-dimensional polymer layer 4, through its triazine ring structure, interacts with Pb... 2+ The coordination and chelation between them form a dense, impermeable ion-barrier layer on the surface of perovskite layer 3, which can effectively inhibit FA.+ / MA + The volatilization and prevention of I - This facilitates cross-interface migration, thereby significantly improving the stability of solar cells at high temperatures.

[0080] The role and effect of the embodiments

[0081] The method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy, the perovskite thin film, and the perovskite device according to the present invention have the following beneficial effects:

[0082] This invention utilizes a two-dimensional polymer (two-dimensional polymer layer 4) containing a triazine ring structure formed on the surface of the perovskite layer 3, and leverages the triazine ring with Pb 2+ N–H...I between - Coordination and cyclic chelation create a dense, impermeable ion-barrier layer at the molecular scale. This barrier layer effectively inhibits A-site organic cations (FA). + MA + The volatilization of ) and halide anions (I) - The cross-interface migration of ions solves the problem of thermal decomposition of perovskite materials caused by ion migration, and significantly improves the lifespan of perovskite device 100 under thermal stress.

[0083] Specifically, the test results from Examples 1 to 6 demonstrate that the two-dimensional polymer layer 4 significantly improves the operational stability (maintaining 90.1% initial efficiency after 1000 hours of maximum power point tracking) and high-temperature thermal stability of the perovskite device 100. After aging at 85°C for 1152 hours, the perovskite device 100 still retains 88.4% of its initial efficiency; under harsh high-temperature conditions at 100°C, the perovskite device 100 retains 81.0% of its initial efficiency after 1020 hours of aging, while the comparative pure perovskite device decays to 25.4% of its initial efficiency in just 24 hours at the same temperature. This indicates that the two-dimensional polymer layer 4 effectively resists thermal stress erosion and significantly delays the performance degradation of the perovskite device 100. Simultaneously, the two-dimensional polymer layer 4 optimizes the interface energy level arrangement, reduces surface potential, and suppresses interface recombination, thereby improving the photoelectric conversion efficiency, open-circuit voltage, and fill factor of the perovskite device 100. In summary, the two-dimensional polymer layer 4 effectively suppresses cation volatilization and anion migration in the perovskite layer 3 at the molecular scale by forming a dense ion-blocking layer. It can significantly extend the lifetime of the perovskite device under thermal stress and operating conditions and improve interface carrier management. It is an ion-locking strategy that combines stability and efficiency improvement.

[0084] The two-dimensional polymer layer 4 of this invention can be directly prepared on the surface of the perovskite layer 3 by conventional methods such as spin coating, blade coating, or slot coating. The process is simple, low-cost, and easy to scale up. Furthermore, this method is not only applicable to perovskite solar cells, but can also be widely used in perovskite devices 100 such as light-emitting diodes, lasers, photodetectors, and field-effect transistors, making it suitable for a wide range of applications.

[0085] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for improving the lifetime of perovskite devices based on two-dimensional polymer ion-locking strategy, characterized by, Includes the following steps: S1: Disperse the two-dimensional polymer in a solvent to obtain a two-dimensional polymer precursor solution; S2: The two-dimensional polymer precursor solution is coated onto the surface of the perovskite layer to form a two-dimensional polymer film. wherein the two-dimensional polymer comprises a triazine ring structure, the triazine ring structure being in place of Pb in perovskite 2+ create coordination and chelation to form a barrier layer that inhibits ion migration.

2. The method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy according to claim 1, characterized in that: wherein The two-dimensional polymer is 2DPA or a derivative thereof.

3. The method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy according to claim 1, characterized in that: wherein The solvent is one or a mixture of isopropanol, chlorobenzene, and N,N-dimethylformamide. The dispersion step includes: stirring at 20~30℃ for 6~48 h. The concentration of the two-dimensional polymer in the two-dimensional polymer precursor solution is 0.1~5.0 mg / mL.

4. The method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy according to claim 1, characterized in that: wherein The material of the perovskite layer is ABX3 organic-inorganic perovskite.

5. The method for improving the lifetime of perovskite devices based on a two-dimensional polymer ion-locking strategy according to claim 1, characterized in that: wherein The coating method is spin coating, blade coating, or slot coating. When the coating method is spin coating, the rotation speed is 3000~6000 rpm and the spin coating time is 50~150 s.

6. A perovskite thin film prepared by the method for improving the lifetime of perovskite devices based on two-dimensional polymer ion locking strategy according to any one of claims 1-5, characterized in that, include: The perovskite layer, A two-dimensional polymer layer is disposed on at least one surface of the perovskite layer.

7. A perovskite device, characterized by: Includes the perovskite thin film as described in claim 6.

8. The perovskite device according to claim 7, characterized in that: wherein, The perovskite device is a solar cell, comprising a substrate and, arranged sequentially along a direction away from the substrate, a hole transport layer, the perovskite layer, the two-dimensional polymer layer, an electron transport layer, a hole blocking layer, and a metal electrode layer.

9. The perovskite device according to claim 8, characterized in that: wherein The substrate material is FTO conductive glass, ITO conductive glass, glass, quartz, or silicon. The hole transport layer is made of 2PACz, Me-2PACz, 4PACz, or Me-4PACz. The preparation method involves dissolving the hole transport layer material in an alcohol solvent to obtain a hole transport layer solution, coating the hole transport layer solution onto the substrate, and annealing to obtain the hole transport layer. The alcohol solvent is one or a mixture of two of ethanol and isopropanol. The material of the electron transport layer is PC 61 BM or C60, when the material of the electron transport layer is C60, the preparation method is: using the C60 as an evaporation source to form the electron transport layer on the two-dimensional polymer layer by an evaporation method, The hole-blocking layer is made of BCP, PEI, or SnO2. When the hole-blocking layer is made of BCP, the preparation method is as follows: using the vapor deposition method, with BCP as the evaporation source, the hole-blocking layer is formed on the electron transport layer. The material of the metal electrode layer is Ag, Au or Cu, and the preparation method is as follows: using the vapor deposition method, the material of the metal electrode layer is used as the evaporation source to form the metal electrode layer on the hole blocking layer.

10. The perovskite device according to claim 7, characterized in that: wherein The perovskite device is a light-emitting diode, a laser, a photodetector, or a field-effect transistor.

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