A method for controlling the low-dimensional structure of perovskite surface based on perovskite complex solvent additives and its photovoltaic application.

Abstract

This invention proposes a method for controlling the low-dimensional structure of perovskite surfaces based on perovskite complex solvent additives and its photovoltaic application. The method includes: Step S1: Adding a perovskite complex solvent additive to a conventional post-treatment solution 1 to obtain solution 2; Step S2: Treating the surface of the original perovskite thin film with solution 2 to achieve controllable control of the low-dimensional structure of the perovskite thin film surface. This invention can induce an increase in the number of octahedral layers in the two-dimensional perovskite structure by adding a small amount of perovskite complex solvent additive to the post-treatment material solution. By increasing the amount of perovskite complex solvent added, the n-value can be controllably increased, weakening the inhibitory effect of the quantum well effect on carrier transport and improving carrier transport. This invention can be applied to optimize the performance of perovskite photovoltaic devices.

Description

Technical Field

[0001] This invention relates to the field of fine structure control technology for semiconductor devices and low-dimensional materials, and particularly to a method for controlling the low-dimensional structure of perovskite surfaces based on perovskite complex solvent additives and its photovoltaic applications. Background Technology

[0002] With increasingly severe environmental pollution and the gradual depletion of traditional energy sources, the development of high-performance photovoltaic technology is crucial. Perovskite photovoltaics have gained attention due to their high photoelectric conversion efficiency and low cost. A typical perovskite photovoltaic structure consists of two electrodes, a perovskite light-absorbing layer, and a charge transport layer. The interface between the perovskite and the charge transport layer contains numerous defects, hindering efficient carrier transport and thus limiting the photovoltaic performance of the solar cell. Numerous studies have reported that post-processing techniques can form an additional two-dimensional perovskite capping layer on the surface of the perovskite film, which has a certain inhibitory effect on carrier recombination, thus improving charge transport and device performance. Generally, the above two-dimensional structure consists of alternating octahedral layers (n layers) and large-size organic cation layers. The large-size organic cation layers exhibit a significant quantum well effect, which restricts carrier transport. Specifically, the smaller the value of n, the stronger the quantum well effect, i.e., the more unfavorable it is to carrier transport. However, for specific post-processing materials, the distribution of the n-value for the low-dimensional structure is relatively fixed, and conventional post-processing techniques cannot easily and controllably adjust the n-value of the low-dimensional structure. Therefore, if a simple and controllable method for regulating the low-dimensional structure of perovskite surfaces can be developed to directionally increase the n-value of the two-dimensional structure, the unfavorable quantum trap effect of the two-dimensional structure can be effectively weakened, and the carrier transport effect can be improved. Thus, when applied to perovskite photovoltaic technology, it can improve the photoelectric conversion efficiency, promote the commercialization and industrialization of photovoltaics, and is of great significance to the country and society's energy conservation and emission reduction development.

[0003] To date, perovskite complexing solvent additives have often been reported for their application in controlling the crystallization of three-dimensional perovskite layers themselves. However, there is currently no report on using perovskite complexing solvents to control the post-treatment solution in order to achieve a controllable modification of the low-dimensional structure n-value of the perovskite film surface; related strategies have not yet been proposed or elucidated. Summary of the Invention

[0004] Current post-processing methods often form a two-dimensional perovskite capping layer on the three-dimensional perovskite surface. The resulting severe quantum well effect restricts carrier transport and hinders further performance improvements in photovoltaic devices. Furthermore, for specific post-processing materials, current techniques still struggle to easily and controllably adjust the n-value and charge transport of the two-dimensional structure, limiting device performance and hindering the industrialization of photovoltaics. Therefore, this invention develops a novel method for controlling the perovskite surface structure using a perovskite complex solvent as an additive. This method utilizes the interaction between the perovskite complex solvent additive and the low-dimensional structure on the three-dimensional perovskite surface to control the low-dimensional structure. Different two-dimensional structures can be induced by changing the additive concentration. Increasing the concentration of the perovskite complex solvent additive can increase the n-value of the low-dimensional structure, or, under high-concentration perovskite complex solvent additive conditions, the post-processed structure can be integrated into the three-dimensional perovskite bulk structure, thereby weakening the quantum well effect limitation caused by low-n-value low-dimensional perovskite and optimizing carrier transport characteristics. Applications of this method include improving the performance of perovskite photovoltaic devices.

[0005] This invention proposes a method for controlling the low-dimensional structure of perovskite surface based on perovskite complex solvent additives. The perovskite complex solvent is added as an additive to the perovskite surface post-treatment solution, and the low-dimensional structure of the perovskite film surface can be controllably reconstructed by changing the additive concentration. This allows for the directional tuning of the n-value distribution of the low-dimensional structure, thereby suppressing the quantum well effect and enhancing carrier transport.

[0006] The technical solution of this invention is achieved as follows: This invention provides a method for regulating the low-dimensional structure of perovskite surface using calcium-based perovskite complex solvent additives, the method comprising the following steps:

[0007] Step S1: Add perovskite complexing solvent additive to solution 1 to obtain solution 2;

[0008] Step S2: Treat the surface of the original perovskite film with the solution 2 to perform low-dimensional structure regulation treatment, and obtain the regulated perovskite film;

[0009] Solution 1 includes reagent a and reagent b.

[0010] The reagent a is characterized in that it can form a low-dimensional structure on the perovskite surface, including but not limited to at least one of phenylethylamine bromide, 2-thiopheneethylamine hydroiodate, phenylethylamine iodide, phenylethylamine chloride, 2-thiopheneethylamine hydrobromide, 2-thiopheneethylamine hydrochloride, benzylamine hydrochloride, benzylamine hydrobromide, benzylamine hydroiodate, benzylamine hydroiodate, 1,3-propanediamine hydroiodate, 1,3-propanediamine hydrobromide, 1,3-propanediamine hydrochloride, cyclopropanediamine hydrochloride, formamidine hydrobromide, guanidine iodide, and metformin; the reagent b is characterized in that it does not dissolve or destroy the perovskite, including but not limited to at least one of isopropanol, n-butanol, chlorobenzene, acetonitrile, toluene, dichloromethane, chloroform, diethyl ether, ethyl acetate, γ-butyrolactone, anisole, methyl benzoate, and diethyl carbonate. The above content is only used to further explain the characteristics of the solution to which the perovskite complexing additive of the present invention is added, and is not intended to limit the specific types of reagents. Under the condition of adding the perovskite complexing additive, the situations in which reagents a and b meet the above-mentioned reagent characteristics are all within the protection scope of the present invention.

[0011] The perovskite complexing solvent additive is characterized by its ability to complex and interact with the perovskite structure, including but not limited to one or more materials selected from N-methylpyrrolidone (NMP), 1,3-dimethyl-2-imidazolinone (DMI), 1,3-dimethyl-3,4,5,6-tetrahydro-2-pyrimidinone (DMPU), hexamethylphosphoric triamine (HMPA), γ-butyrolactone (GBL), tetramethylurea (TMU), and N-methylformamide (NMF). Preferably, the perovskite complexing solvent additive is N-methylpyrrolidone.

[0012] Based on the above technical solution, in step S1, the volume ratio of the perovskite complex solvent additive to the solution 1 is less than or equal to 1:10. Preferably, in step S1, the volume ratio of the perovskite complex solvent additive to the solution 1 is less than or equal to 1:50.

[0013] Based on the above technical solutions, preferably, in step S2, the general formula of the original perovskite thin film is ABX3.

[0014] in,

[0015] A is a monovalent cation, including methylamine ion (MA). + ), formamidinium ion (FA) + ), dimethylamine ion (DMA) + ), Cs + At least one of them;

[0016] B is a divalent cation, including Pb. 2+ Sn 2+ At least one of them;

[0017] X is a monovalent anion, including I. - ,Br - Cl - SCN - At least one of the formate ions.

[0018] Based on the above technical solutions, preferably, the original perovskite film composition is Cs. 0.05 MA 0.1 FA 0.85 or Cs 0.05 MA 0.22 FA 0.73 Pb(I 0.77 Br 0.23 )3, which are typical components of conventional bandgap and wide bandgap perovskites, are only used to describe the implementation effect of the present invention more clearly and specifically in the examples, and are not intended to limit the application scope of the present invention.

[0019] Based on the above technical solutions, preferably, in step S2, the control treatment method includes one or more of the following: scraping coating, slot coating, spin coating, screen printing, inkjet printing, or metering rod coating, so that the solution 2 comes into contact with the surface of the original perovskite film.

[0020] Based on the above technical solution, preferably, step S2 further includes annealing the original perovskite film after conditioning treatment at 50-150°C for 1-30 minutes to obtain the conditioned perovskite film.

[0021] According to another aspect of the present invention, a regulated perovskite thin film prepared by the above-described method for regulating the low-dimensional structure of the perovskite surface is provided.

[0022] According to another aspect of the present invention, a regulated perovskite thin film prepared by the above-described method for regulating the low-dimensional structure of the perovskite surface is provided, or the above-described regulated perovskite thin film is used in semiconductor devices and photovoltaic fields.

[0023] As a specific implementation method, the present invention is achieved through the following technical solution:

[0024] A method for regulating the surface structure of perovskite based on perovskite complex solvent additives, the method comprising the following steps:

[0025] (1) Mix reagent a, reagent b, and perovskite complexing solvent additive to obtain a solution;

[0026] (2) Based on the solution method, the surface of the perovskite film is treated with the solution described in step 1). Based on the amount of different perovskite complexing solvent additives added, different two-dimensional fine structure control can be achieved, inducing changes in the n value and changing the carrier transport.

[0027] It should be understood that in step (1) of the perovskite solar cell fabrication process described in this invention, reagent a needs to form a two-dimensional structure on the surface of the perovskite thin film. Reagent a includes, but is not limited to, phenylethylamine bromide (PEABr), 2-thiopheneethylamine hydroiodide (2-ThEAI), phenylethylamine iodide, phenylethylamine chloride, 2-thiopheneethylamine hydrobromide, 2-thiopheneethylamine hydrochloride, benzylamine hydrochloride, benzylamine hydrobromide, benzylamine hydroiodide, benzylamine hydrochloride, benzylamine hydrobromide, 1,3 One or more of the following perovskite surface post-treatment materials are selected: 1,3-propanediamine hydroiodate, 1,3-propanediamine hydrobromide, cyclopropanediamine hydrochloride, formamidine hydrobromide, guanidine iodide, metformin, etc. Reagent b needs to dissolve the post-treatment material but must not damage the perovskite film itself. This includes, but is not limited to, one or more non-polar or weakly polar solvents such as isopropanol, n-butanol, chlorobenzene, acetonitrile, toluene, dichloromethane, chloroform, diethyl ether, ethyl acetate, γ-butyrolactone, anisole, methyl benzoate, and diethyl carbonate. The above description is only used to further explain the characteristics of the solution to which the perovskite complexing additive of the present invention is added and is not intended to limit the specific types of reagents. Under the condition of adding the perovskite complexing additive, reagents a and b that meet the above-described reagent characteristics are all within the scope of protection of the present invention.

[0028] It should be noted that the ratio of the volume of the perovskite complex solvent additive to the total volume of other solvents is not limited to a specific value. The distribution of the n-value of the two-dimensional structure can be tuned by adding perovskite complex solvent additives of different concentrations, thereby achieving controllable low-dimensional fine structure regulation.

[0029] This invention can induce an increase in the number of octahedral layers in a two-dimensional structure by adding a small amount of perovskite complexing solvent additive to the post-treatment material solution. Increasing the amount of perovskite complexing solvent increases the n-value, thereby enhancing the fine structure n-value, reducing the inhibitory effect of the quantum well effect on charge carrier transport, and improving charge carrier transport characteristics. Furthermore, introducing a large amount of perovskite complexing solvent additive can induce direct fusion between the post-treatment material structure and the three-dimensional perovskite, thus suppressing charge carrier recombination in the three-dimensional perovskite bulk phase and promoting charge carrier transport. Therefore, this invention can controllably alter the layered fine structure of low-dimensional materials, directionally tune the n-value, and thereby suppress the quantum well's obstruction of charge transport and improve charge carrier transport.

[0030] This invention can also induce a greater integration of the post-processed material structure with the three-dimensional perovskite by introducing a large amount of perovskite complexing solvent, effectively introducing the post-processed structure into the interior of the three-dimensional perovskite. This transforms the low-n-value two-dimensional structure into a high-n-value two-dimensional structure while alleviating the carrier recombination problem in the three-dimensional perovskite bulk phase, synergistically optimizing carrier transport performance. This invention can be applied to improve the device performance of perovskite photovoltaics.

[0031] The perovskite surface structure control method of the present invention has the following advantages over the prior art:

[0032] (1) The present invention induces an increase in the number of octahedral layers in the two-dimensional structure by adding a small amount of perovskite complex solvent additive. Increasing the amount of perovskite complex solvent additive is beneficial to improving the n value, weakening the influence of quantum well effect, and optimizing carrier transport characteristics.

[0033] (2) This invention induces the post-treated material structure to fuse with the three-dimensional perovskite body by adding a large number of perovskite complexing solvent additives. While suppressing the quantum well effect of the low-dimensional structure on the surface, it can also improve the recombination of perovskite phase defects and synergistically optimize the carrier transport effect.

[0034] (3) The perovskite surface structure control method of the present invention can be applied to perovskite photovoltaics, and the effect of improving the efficiency of perovskite photovoltaics is significant. Attached Figure Description

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

[0036] Figure 1 This is a schematic diagram illustrating the effects of traditional perovskite film surface post-treatment and the effects of perovskite surface structure regulation based on perovskite complex solvent additive post-treatment.

[0037] Figure 2 The images show the fluorescence spectra of glass / perovskite samples from Comparative Examples 1-2 and Examples 1-3 of this invention.

[0038] Figure 3 The glass / perovskite / C glass of Comparative Examples 1-2 and Example 3 of this invention 60 Fluorescence spectrum of the sample.

[0039] Figure 4 This is a JV curve diagram of the perovskite solar cell of Comparative Example 1 of the present invention.

[0040] Figure 5This is a JV curve of the perovskite solar cell of Comparative Example 2 of the present invention.

[0041] Figure 6 This is a JV curve of the perovskite solar cell of Comparative Example 3 of the present invention.

[0042] Figure 7 This is a JV curve of the perovskite solar cell of Comparative Example 4 of the present invention.

[0043] Figure 8 This is a JV curve of the perovskite solar cell of Comparative Example 5 of the present invention.

[0044] Figure 9 This is a JV curve diagram of the perovskite solar cell of Embodiment 1 of the present invention.

[0045] Figure 10 This is a JV curve diagram of the perovskite solar cell of Embodiment 2 of the present invention.

[0046] Figure 11 This is a JV curve diagram of the perovskite solar cell of Example 3 of the present invention.

[0047] Figure 12 This is a JV curve diagram of the perovskite solar cell of Example 4 of the present invention.

[0048] Figure 13 This is a JV curve diagram of the perovskite solar cell of Example 5 of the present invention.

[0049] Figure 14 This is a JV curve diagram of the perovskite solar cell of Embodiment 6 of the present invention.

[0050] Figure 15 This is a JV curve diagram of the perovskite solar cell of Example 7 of the present invention. Detailed Implementation

[0051] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0052] Example 1

[0053] This embodiment provides a method for regulating the surface structure of perovskite based on perovskite complex solvent additives, including the following steps:

[0054] S1, prepared at a concentration of 7.5 mmol / L -1An isopropanol (IPA) solution of 2-thiophene ethylamine hydroiodide (2-ThEAI) was added to the initial post-treatment solution, and NMP additive (the NMP is the perovskite complex solvent additive of the example, and the volume ratio of NMP to IPA is 1:500) was added. The solution was then repeatedly shaken to homogenize it using a shaker.

[0055] S2. Under a nitrogen atmosphere, the perovskite film is rotated at an acceleration of 5000 rpm for 30 seconds. Approximately 5 seconds after the start of rotation, 50 μL of the optimized post-treatment solution described in S1 is dropped onto the center of the perovskite film. After spin coating, the perovskite film sample is annealed at 70°C for 10 minutes and cooled to room temperature to obtain the post-treated sample.

[0056] To visually demonstrate the application effect of this embodiment, a perovskite solar cell was fabricated based on the perovskite thin film obtained in Example 1, and device performance was tested and compared from the perspective of device performance. It should be noted that the device fabrication described is only for demonstrating the specific practical effects of this invention. Except for A4, which emphasizes the content of this invention, all other device fabrication methods described below are conventional fabrication methods in the field unless otherwise specified. Unless otherwise specified, all materials are commercially available. The specific steps include:

[0057] A1. Clean the ITO / glass substrate and perform ultraviolet-ozone treatment.

[0058] A2. Spin-coat 4-(7H-dibenzo[c,g]carbazole-7-yl)butylphosphonic acid (4PADCB) onto the above substrate as a hole transport layer.

[0059] A3. Cs was prepared by spin coating under nitrogen protection. 0.05 MA 0.1 FA 0.85 Perovskite thin film, used as a perovskite light-absorbing layer.

[0060] A4. Prepare a post-treatment solution containing NMP and treat the surface of the perovskite film described in A3:

[0061] S1, prepared at a concentration of 7.5 mmol / L -1 The 2-ThEAI IPA solution was added to the initial post-treatment solution with NMP additive (NMP to IPA volume ratio of 1:500), and the solution was shaken to homogenize.

[0062] S2. Under a nitrogen atmosphere, the perovskite film is rotated at an acceleration of 5000 rpm for 30 seconds. Approximately 5 seconds after the start of rotation, 50 μL of the optimized post-treatment solution described in S1 is dropped onto the center of the perovskite film. After spin coating, the perovskite film sample is annealed at 70°C for 10 minutes and cooled to room temperature to obtain the post-treated sample.

[0063] A5. Using a vapor deposition method, 25nm C was sequentially deposited on the samples obtained in A4. 60 A 6nm BCP thin film is used as the electron transport layer of the device.

[0064] A6. A 100 nm Ag thin film is deposited on the sample obtained in A5 using the vapor deposition method to serve as the top electrode of the device, thus completing the device fabrication.

[0065] Example 2

[0066] This embodiment provides a method for controlling the surface structure of perovskite based on NMP, as well as a related device fabrication process. The specific operation steps are the same as in Embodiment 1, except that the volume ratio of NMP to IPA in step S1 is 3:500.

[0067] Example 3

[0068] This embodiment provides a method for controlling the surface structure of perovskite based on NMP, as well as a related device fabrication process. The specific operation steps are the same as in Embodiment 1, except that the volume ratio of NMP to IPA in step S1 is 1:125.

[0069] Example 4

[0070] This embodiment provides a method for controlling the surface structure of perovskite based on NMP, as well as a related device fabrication process. The specific operation steps are the same as in Embodiment 1, except that the volume ratio of NMP to IPA in step S1 is 1:100.

[0071] Example 5

[0072] This embodiment provides a method for controlling the surface structure of perovskites based on NMP, as well as a related device fabrication process. The specific operation steps are the same as in Embodiment 3, except that the post-treatment material used in step S1 is phenylethyl ammonium bromide (PEABr) instead of 2-ThEAI.

[0073] Example 6

[0074] This embodiment provides a method for controlling the surface structure of perovskites based on NMP, as well as a related device fabrication process. The specific operation steps are the same as in Embodiment 4, except that the post-treatment material used in step S1 is phenylethyl ammonium bromide (PEABr) instead of 2-ThEAI.

[0075] Example 7

[0076] This embodiment provides a method for controlling the surface structure of perovskite based on NMP, as well as a related device fabrication process. The specific operation steps are the same as in Embodiment 3, except that the wide-bandgap perovskite with a chemical composition of Cs is used in step A3 of the device fabrication. 0.05 MA 0.22 FA 0.73 Pb(I 0.77 Br 0.23 )3; In step S1, the volume ratio of NMP to IPA is 1:250; C is deposited in step S1. 60 Previously, an additional 1nm LiF thin film was deposited by vapor deposition.

[0077] Comparative Example 1

[0078] This embodiment provides a method for controlling the surface structure of perovskites based on NMP, as well as a related device fabrication process. The specific operation steps are the same as in Embodiment 1, except that no operation is performed in steps S1 and S2.

[0079] Comparative Example 2

[0080] This embodiment provides a method for controlling the surface structure of perovskites based on NMP, as well as a related device fabrication process. The specific operation steps are the same as in Embodiment 1, except that the NMP addition operation in step S1 is not performed.

[0081] Comparative Example 3

[0082] This embodiment provides a method for controlling the surface structure of perovskites based on NMP, as well as a related device fabrication process. The specific operation steps are the same as in Embodiment 5, except that the NMP addition operation in step S1 is not performed.

[0083] Comparative Example 4

[0084] This embodiment provides a method for controlling the surface structure of perovskites based on NMP, as well as a related device fabrication process. The specific operation steps are the same as in Embodiment 7, except that no operation is performed in steps S1 and S2.

[0085] Comparative Example 5

[0086] This embodiment provides a method for controlling the surface structure of perovskites based on NMP, as well as a related device fabrication process. The specific operation steps are the same as in Embodiment 7, except that the NMP addition operation in step S1 is not performed.

[0087] Figure 1This diagram illustrates the principles of three perovskite surface structure control strategies: conventional post-processing, a strategy based on a small amount of perovskite complex solvent additives, and a strategy based on a large amount of perovskite complex solvent additives. Conventional post-processing methods primarily limit their control to the perovskite surface, making it difficult to efficiently eliminate defects within the three-dimensional structure. Furthermore, the resulting two-dimensional capping layer often creates a severe quantum well effect, inhibiting efficient carrier transport. Using a small amount of perovskite complex solvent additives to interact with the perovskite surface induces changes in the two-dimensional structure. Increasing the amount of perovskite complex solvent additives leads to an increase in the n-value of the two-dimensional structure (an increase in the number of octahedral layers), thereby weakening the quantum well effect and improving charge transport. Using a large amount of perovskite complex solvent additives for stronger interaction with the perovskite surface can more effectively induce a further increase in the n-value, improving the quantum well effect. Simultaneously, it facilitates the integration of the post-processed material structure into the three-dimensional perovskite bulk structure, thus synergistically improving charge transport.

[0088] Figure 2 The fluorescence spectra of glass / perovskite samples from Comparative Examples 1-2 and Examples 1-3 are presented to characterize the evolution of low-dimensional structures and the nonradiative recombination of charge carriers in the perovskite film itself. The experimental results are based on NMP, a perovskite complexing solvent additive, and are intended for illustrative purposes only and not to limit the invention. The left figure shows the test results for each sample in the 450–700 nm wavelength range. Comparative Example 1 is a three-dimensional perovskite sample without any post-processing, and no significant low-dimensional characteristic peaks appear in this wavelength range. Comparative Example 2 is a sample treated with a conventional post-processing scheme; its fluorescence spectrum shows a significant characteristic peak of a two-dimensional structure (n=1). The small n value significantly suppresses charge carrier transport. In contrast, the test curve of Example 1 also shows a two-dimensional structure characteristic peak, but its peak position is further to the right than that of Comparative Example 2, indicating that the interaction between the perovskite complexing solvent additive and the surface structure can indeed induce an increase in the n value (n=2). As the dosage of the perovskite complexing solvent increased further, in Example 2, in addition to a characteristic peak appearing in the 525–600 nm range, a characteristic peak also appeared in the 600–675 nm range (n=3), indicating that further increasing the amount of perovskite complexing solvent additive would cause the n value to shift to a higher value. For Example 3, when the amount of perovskite complexing solvent additive continued to increase, it became difficult to observe significant characteristic peaks in the 450–750 nm band, and the curves corresponding to the low-dimensional structure near 700 nm and the three-dimensional structure near 800 nm were highly integrated. Figure 2 The right figure illustrates that as the n-value of the low-dimensional perovskite further increases (exceeding 3), it induces the fusion of its functional and three-dimensional structures. This pattern confirms that the fine layer structure of the low-dimensional structure on the surface of the perovskite film undergoes significant changes after adding different amounts of perovskite complexing solvent additives. Figure 2 The right figure shows the fluorescence spectral results in the 450–975 nm band. The characteristic peaks in this band correspond to the three-dimensional perovskite phase. The order of fluorescence peak intensity for each sample in this band is: Example 3 > Example 2 > Example 1 > Comparative Example 2 > Comparative Example 1. The above experimental results demonstrate that although traditional post-processing methods can weaken and improve nonradiative recombination of charge carriers, the method proposed in this invention provides a better improvement. Note the above... Figure 2 The left image is only Figure 2 The enlarged view on the right makes it easier to observe and analyze.

[0089] To demonstrate the altered carrier transport behavior in perovskite / charge transport layers, this invention presents glass / perovskite / C glass in Comparative Example 1, Comparative Example 2, and Example 1. 60 Fluorescence spectroscopy test results of the samples (e.g.) Figure 3 (As shown). The fluorescence peak intensity order of each sample is: Comparative Example 1 > Comparative Example 2 > Example 3. (Combined with...) Figure 2 and Figure 3 The test results show that although traditional post-processing methods can improve carrier transport between perovskite / charge transport layers, the method proposed in this invention has a better improvement effect.

[0090] To intuitively demonstrate the application value of the novel low-dimensional fine structure reconstruction method described in this invention, the performance of the perovskite solar cell devices prepared in Examples 1-7 and Comparative Examples 1-5 is analyzed below. Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 The JV curves and parameters of perovskite solar cells for comparative examples 1, 2, 3, 4, and 5 are shown respectively. Figure 9 , Figure 10 , Figure 11 , Figure 12 , Figure 13 , Figure 14 , Figure 15 The JV curves and parameters of perovskite solar cells in Examples 1, 2, 3, 4, 5, 6, and 7 are shown respectively. Figure 4-15 The test results were all conducted under sunlight simulator illumination conditions (illuminance of 100 mW / cm²). -2 The following analysis compares and contrasts the device performance under various conditions obtained from the data.

[0091] First, the perovskite complex solvent additive strategy proposed in this invention can improve the performance of perovskite photovoltaics. Comparative Example 1, Comparative Example 2, and Examples 1-3 are typical examples analyzed. Compared to Comparative Example 1, although Comparative Example 2, which does not use perovskite complex solvent additives, can improve the device's photoelectric conversion efficiency, Examples 1-3, based on the perovskite complex solvent additive strategy proposed in this invention, show a more significant improvement in device efficiency.

[0092] For different types of post-processing materials, the perovskite complex solvent additive strategy proposed in this invention also has the effect of improving device performance. Examples are given below: Compared to Comparative Example 2 and Examples 1-4, Comparative Example 3 and Examples 5-6 used different post-processing materials. Comparative Example 3 showed better device performance than Comparative Example 1, indicating that different post-processing materials are also effective in improving device performance. However, Examples 5-6, based on the perovskite complex solvent additive post-processing strategy, were significantly more efficient, demonstrating that even with different post-processing materials, the strategy proposed in this invention has a more significant effect on improving device performance.

[0093] This invention can regulate the improvement effect on device performance by using different amounts of perovskite complex solvent additives. Examples are provided below: Although Examples 1-4 used the same perovskite complex solvent additive, the different amounts resulted in different performance improvements. When the volume ratio of the perovskite complex solvent additive to IPA increased from 0 to 1:125, the device performance improved accordingly. Similarly, Examples 5-6 used the same post-treatment materials and solvent additives, but different amounts of perovskite complex solvent additives resulted in different performance improvements. It is understood that excessive introduction of perovskite complex solvent additives may lead to unfavorable over-dissolution and damage of the three-dimensional perovskite, resulting in deterioration of device performance. For example, when the volume ratio used in Example 4 was as high as 1:100, the device performance of Example 4 decreased compared to Example 3.

[0094] For perovskites with different compositions, the novel strategy based on perovskite complex solvent additives described in this invention can also improve device performance. The following examples illustrate this: by analyzing Comparative Examples 4, 5 and Example 7 with different perovskite compositions and the above-mentioned situations, it can be found that the performance of the perovskite solar cell in Example 7 is significantly higher than that in Comparative Examples 4 and 5.

[0095] In summary, the perovskite surface structure control method based on perovskite complex solvent additives proposed in this invention has several advantages: by simply adding perovskite complex solvent additives and adjusting their concentration, the n-value of the two-dimensional structure can be controllably induced to change to varying degrees, thereby achieving directional changes in the corresponding low-dimensional fine structure, and the device performance can also be altered accordingly. For different post-processing materials or different perovskites, the strategy proposed in this invention can also effectively improve the photoelectric conversion efficiency of the corresponding photovoltaics.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling the low-dimensional structure of perovskite surfaces based on perovskite complex solvent additives, characterized in that, The method for controlling the low-dimensional structure of the perovskite surface includes the following steps: Step S1: Add perovskite complexing solvent additive to solution 1 to obtain solution 2; Step S2: Use the solution 2 to perform low-dimensional structure regulation treatment on the surface of the original perovskite film to obtain the regulated perovskite film; in, The solution 1 includes at least reagent a and reagent b. The reagent a is characterized in that it can form a low-dimensional structure on the perovskite surface, including but not limited to at least one of phenylethylamine bromide, 2-thiopheneethylamine hydroiodide, phenylethylamine iodide, phenylethylamine chloride, 2-thiopheneethylamine hydrobromide, 2-thiopheneethylamine hydrochloride, benzylamine hydrochloride, benzylamine hydrobromide, benzylamine hydroiodide, benzylamine hydroiodide, 1,3-propanediamine hydroiodide, 1,3-propanediamine hydrobromide, 1,3-propanediamine hydrochloride, cyclopropylformamidinium hydrochloride, formamidinium hydrobromide, guanidine iodide, and metformin; The reagent b is characterized in that it does not dissolve or destroy perovskite, including but not limited to at least one of isopropanol, n-butanol, chlorobenzene, acetonitrile, toluene, dichloromethane, chloroform, diethyl ether, ethyl acetate, γ-butyrolactone, anethole, methyl benzoate, and diethyl carbonate. The perovskite complexing solvent additive is characterized by its ability to undergo complexation interaction with perovskite, including but not limited to one or more of N-methylpyrrolidone (NMP), 1,3-dimethyl-2-imidazolinone (DMI), 1,3-dimethyl-3,4,5,6-tetrahydro-2-pyrimidinone (DMPU), hexamethylphosphoric triamine (HMPA), γ-butyrolactone (GBL), tetramethylurea (TMU), and N-methylformamide (NMF).

2. The method for controlling the low-dimensional structure of perovskite surfaces as described in claim 1, characterized in that, In step S1, the volume ratio of the perovskite complex solvent additive to the solution 1 is less than or equal to 1:

10.

3. The method for controlling the low-dimensional structure of perovskite surfaces as described in claim 1, characterized in that, In step S1, the volume ratio of the perovskite complex solvent additive to the solution 1 is less than or equal to 1:

50.

4. The method for controlling the low-dimensional structure of perovskite surfaces as described in claim 1, characterized in that, In step S2, the chemical formula of the original perovskite film is ABX3. in, A is a monovalent cation, including methylamine ion (MA). + ), formamidinium ion (FA) + ), dimethylamine ion (DMA) + ), Cs + At least one of them; B is a divalent cation, including Pb. 2+ Sn 2+ At least one of them; X is a monovalent anion, including I. - ,Br - Cl - SCN - At least one of the formate ions.

5. The method for controlling the low-dimensional structure of perovskite surfaces as described in claim 1, characterized in that, In step S2, the control treatment method includes one or more of the following: scraping coating, slot coating, spin coating, screen printing, inkjet printing, or metering rod coating, so that the solution 2 comes into contact with the surface of the original perovskite film.

6. The method for controlling the low-dimensional structure of perovskite surfaces as described in claim 1, characterized in that, Step S2 further includes annealing the treated perovskite film at 50~150 °C for 1-30 minutes.

7. The regulated perovskite thin film prepared by the method for regulating the low-dimensional structure of the perovskite surface according to any one of claims 1 to 6.

8. The application of the regulated perovskite thin film prepared by the method for regulating the low-dimensional structure of the perovskite surface according to any one of claims 1 to 6, or the regulated perovskite thin film according to claim 7, in semiconductor devices and photovoltaic fields.

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