Perovskite surface low-dimensional structure regulation and control method based on perovskite complex solvent additive and photovoltaic application

Abstract

The invention provides a perovskite surface low-dimensional structure regulation and control method based on a perovskite complex solvent additive and photovoltaic application, and the method comprises the steps: S1, adding the perovskite complex solvent additive into a conventional post-treatment solution 1, and obtaining a solution 2; and S2, treating the surface of the original perovskite thin film by using the solution 2 to realize controllable regulation and control of the low-dimensional structure on the surface of the perovskite thin film. The number of octahedral layers of the two-dimensional perovskite structure can be induced to be increased through a small amount of perovskite complex solvent additive in the post-treatment material solution, the n value can be controllably increased by increasing the adding amount of the perovskite complex solvent, the inhibition effect of the quantum well effect on carrier transport is weakened, and carrier transport is improved. The method can be used for optimizing the performance of the perovskite photovoltaic device.

Description

Technical Field

[0001] The present invention relates to the technical field of fine structure regulation of semiconductor devices and low-dimensional materials, and in particular to a method for regulating the low-dimensional structure of a perovskite surface based on a perovskite complex solvent additive and photovoltaic applications. Background Art

[0002] Environmental pollution is becoming increasingly serious, and traditional energy is gradually becoming scarce. It is crucial to develop high-performance photovoltaic technology. Perovskite photovoltaics have gained people's attention due to their advantages such as high photoelectric conversion efficiency and low cost. The typical perovskite photovoltaic structure consists of two-terminal electrodes, a perovskite light-absorbing layer, and a charge transport layer. There are a large number of defects at the interface between the perovskite and the charge transport layer, which hinder the efficient transport of carriers, thereby limiting the photovoltaic performance of solar cells. A large number of studies have reported that the use of post-treatment processes can form an additional two-dimensional perovskite covering layer on the surface of the perovskite film, which has a certain inhibitory effect on the defect recombination of carriers, thereby improving charge transport and improving device performance. In general, the above-mentioned two-dimensional structure is composed of an octahedral layer (the number of octahedral layers is n) and a large-sized organic cation layer alternately, in which the large-sized organic cation layer has a significant quantum well effect, which has a limiting effect on carrier transport. In particular, the smaller the n value, the stronger the quantum well effect, that is, the less conducive to carrier transport. However, for a specific post-treatment material, the distribution of the n value of the generated low-dimensional structure is relatively fixed, and it is difficult for conventional post-treatment processes to simply and controllably adjust the n value of the low-dimensional structure. Therefore, if a method for regulating the low-dimensional structure of the perovskite surface that is easy to operate and highly controllable can be developed to directionally increase the n value of the two-dimensional structure, the unfavorable quantum well effect of the two-dimensional structure can be effectively weakened, and the carrier transport effect can be improved. Therefore, when applied to perovskite photovoltaic technology, the photoelectric conversion efficiency can be improved, and the commercialization and industrialization of photovoltaics can be promoted, which is of great significance to the energy conservation and emission reduction development of the country and society.

[0003] So far, perovskite complex solvent additives are often reported to be used for the crystallization regulation of the three-dimensional perovskite layer itself. However, there is no report on the specific method of regulating the post-treatment solution by using perovskite complex solvent to achieve the effect of controllable modification of the low-dimensional structure n value on the surface of the perovskite film, and the relevant strategy has not been proposed and clarified. Summary of the invention

[0004] The post-treatment methods reported in current research often form a two-dimensional perovskite covering layer on the surface of the three-dimensional perovskite, and the severe quantum well effect that follows restricts carrier transport and hinders further improvement of photovoltaic device performance. In addition, for specific post-treatment materials, the current post-treatment technology is still difficult to adjust the n value and charge transport of the two-dimensional structure by a simple and controllable method, which limits the improvement of device performance and hinders the development of related photovoltaic industrialization. Based on this, the present invention has developed a new method for regulating the surface structure of perovskite based on perovskite complex solvent as an additive, using the above-mentioned perovskite complex solvent additive to interact with the low-dimensional structure on the surface of the three-dimensional perovskite to regulate the low-dimensional structure of the perovskite, and different two-dimensional structures can be induced by changing the concentration of the additive. The n value of the low-dimensional structure can be increased by increasing the concentration of the perovskite complex solvent additive, or the post-treatment structure can be realized to enter the three-dimensional perovskite bulk phase structure under the condition of high concentration of the perovskite complex solvent additive, thereby weakening the quantum well effect limitation brought by the low-n value low-dimensional perovskite and optimizing the carrier transport characteristics. The application of this method includes improving the performance of perovskite photovoltaic devices.

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

[0006] The technical solution of the present invention is implemented as follows: The present invention provides a method for regulating the low-dimensional structure of the perovskite surface based on a calcium-based perovskite complex solvent additive, and the method for regulating the low-dimensional structure of the perovskite surface comprises the following steps:

[0007] Step S1: adding a perovskite complex solvent additive to solution 1 to obtain solution 2;

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

[0009] Wherein, the 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 surface of perovskite, including but not limited to at least one of phenethylammonium bromide, 2-thiopheneethylamine hydroiodide, phenethylammonium iodide, phenethylammonium chloride, 2-thiopheneethylamine hydrobromide, 2-thiopheneethylamine hydrochloride, benzylamine hydrochloride, benzylamine hydrobromide, benzylamine hydroiodide, benzamidine hydrochloride, benzamidine hydrobromide, benzamidine hydroiodide, 1,3-propylenediamine hydroiodide, 1,3-propylenediamine hydrobromide, 1,3-propylenediamine hydrochloride, cyclopropylformamidine hydrochloride, formamidine hydrobromide, guanidine iodide, and metformin; the reagent b is characterized in that it does not dissolve and destroy the perovskite, including but not limited to at least one of isopropanol, n-butanol, chlorobenzene, acetonitrile, toluene, dichloromethane, chloroform, 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 complex additive of the present invention is added, and is not used to limit the specific types of reagents. Under the condition of adding the perovskite complex additive, the situations where reagents a and b meet the above reagent characteristics are within the protection scope of the present invention.

[0011] The perovskite complexing solvent additive is characterized in that it can be complexed with the perovskite structure and interact with it, including but not limited to one or more materials in N-methylpyrrolidone (NMP), 1,3-dimethyl-2-imidazolidinone (DMI), 1,3-dimethyl-3,4,5,6-tetrahydro-2-pyrimidone (DMPU), hexamethylphosphoric triamide (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 solution, preferably, in step S2, the general formula of the original perovskite 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;

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

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

[0018] On the basis of the above technical solution, 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, are typical components of conventional bandgap and wide bandgap perovskites, respectively, and are only used to more clearly and specifically describe the implementation effects of the present invention in the embodiments, and are not used to limit the scope of application of the present invention.

[0019] On the basis of the above technical scheme, preferably, in step S2, the regulation treatment method includes one or more of blade coating, slit coating, spin coating, screen printing, inkjet printing or metering rod coating, so that the solution 2 is in contact with the surface of the original perovskite film.

[0020] On the basis of the above technical solution, preferably, step S2 further comprises annealing the original perovskite film after the regulation treatment at 50-150° C. for 1-30 minutes to obtain a regulated perovskite film.

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

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

[0023] As a specific implementation, the present invention is implemented by the following technical solutions:

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

[0025] (1) mixing reagent a, reagent b, and a perovskite complex 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), and the fine structure control of different two-dimensional structures can be achieved based on the addition amount of different perovskite complex solvent additives, inducing changes in n value and changing carrier transport.

[0027] It should be understood that in step (1) of the perovskite solar cell preparation process of the present invention, the reagent a needs to form a two-dimensional structure on the surface of the perovskite film, and the reagent a includes but is not limited to phenethylammonium bromide (PEABr), 2-thiopheneethylamine hydroiodide (2-ThEAI), phenethylammonium iodide, phenethylammonium chloride, 2-thiopheneethylamine hydrobromide, 2-thiopheneethylamine hydrochloride, benzylamine hydrochloride, benzylamine hydrobromide, benzylamine hydroiodide, benzamidine hydrochloride, benzamidine hydrobromide, benzamidine hydroiodide, 1,3 -propylene diamine hydroiodide, 1,3-propylene diamine hydrobromide, 1,3-propylene diamine hydrochloride, cyclopropylcarboxamidine hydrochloride, carboxamidine hydrobromide, guanidine iodide, metformin and other perovskite surface post-treatment materials, the reagent b needs to dissolve the post-treatment material, but cannot damage the perovskite film itself, including but not limited to isopropanol, n-butanol, chlorobenzene, acetonitrile, toluene, dichloromethane, chloroform, ether, ethyl acetate, γ-butyrolactone, anisole, methyl benzoate, diethyl carbonate and other non-polar or weakly polar solvents. The above content is only used to further explain the characteristics of the solution added to the perovskite complex additive of the present invention, and is not used to limit the specific reagent types. Under the condition of adding the perovskite complex additive, the situations where reagents a and b meet the above reagent characteristics are within the protection scope of the present invention.

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

[0029] The present invention can induce an increase in the number of octahedral layers of a two-dimensional structure by a small amount of a perovskite complex solvent additive in a post-processing material solution, increase the n value by increasing the amount of perovskite complex solvent added, increase the fine structure n value, weaken the inhibitory effect of the quantum well effect on carrier transport, and improve the carrier transport characteristics; and can also induce the direct fusion of the post-processing material structure with the three-dimensional perovskite by introducing a large amount of perovskite complex solvent additives, thereby inhibiting the recombination of three-dimensional perovskite bulk phase carriers and promoting the carrier transport effect. Therefore, the present invention can controllably change the layered fine structure of low-dimensional materials, directionally tune the n value, and then inhibit the quantum well from hindering charge transport and improve carrier transport.

[0030] The present invention can also induce a greater fusion of the post-processing material structure with the three-dimensional perovskite by introducing a large amount of perovskite complexing solvent, effectively introduce the post-processing structure into the three-dimensional perovskite, and while converting the low-n value two-dimensional structure to the high-n value two-dimensional structure, alleviate the three-dimensional perovskite bulk phase carrier recombination problem and synergistically optimize the carrier transmission effect. The present 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 beneficial effects compared with the prior art:

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

[0033] (2) The present invention uses a large amount of perovskite complex solvent additives to induce the post-processing material structure to merge with the three-dimensional perovskite body, which can suppress the quantum well effect of the surface low-dimensional structure and improve the perovskite body phase defect recombination, thereby synergistically optimizing the carrier transport effect;

[0034] (3) The perovskite surface structure regulation method of the present invention can be applied to perovskite photovoltaics, and has a significant effect in improving the efficiency of perovskite photovoltaics. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 Schematic diagram of the principle of the traditional perovskite film surface post-treatment effect and the perovskite surface structure regulation effect based on perovskite complex solvent additive post-treatment.

[0037] Figure 2 It is the fluorescence spectra of the glass / perovskite samples of Comparative Examples 1-2 and Examples 1-3 of the present invention.

[0038] Figure 3 The glass / perovskite / C of Comparative Examples 1-2 and Example 3 of the present invention 60 Fluorescence spectra of the samples.

[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 diagram of the perovskite solar cell of Comparative Example 2 of the present invention.

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

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

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

[0044] Fig. 9 This is a JV curve diagram of the perovskite solar cell according to Example 1 of the present invention.

[0045] Fig.10 This is a JV curve diagram of the perovskite solar cell according to Example 2 of the present invention.

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

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

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

[0049] Fig.14 This is a JV curve diagram of the perovskite solar cell according to Example 6 of the present invention.

[0050] Fig.15 This is a JV curve diagram of the perovskite solar cell according to Example 7 of the present invention. DETAILED DESCRIPTION

[0051] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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 a perovskite complex solvent additive, comprising the following steps:

[0054] S1, prepared at a concentration of 7.5 mmol L -1An isopropyl alcohol (IPA) solution of 2-thiopheneethylamine hydroiodide (2-ThEAI) is prepared, and an NMP additive is added to the initial post-treatment solution (the NMP is the perovskite complex solvent additive of the embodiment, and the volume ratio of NMP to IPA is 1:500), and the uniform solution is repeatedly oscillated using an oscillator.

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

[0056] In order to intuitively demonstrate the application effect of this embodiment, the present invention prepares a perovskite solar cell based on the perovskite film obtained in Example 1, and performs device performance tests, and conducts comparative analysis from the perspective of device performance. It is particularly noted that the device preparation is only used to demonstrate the specific practical effects of the present invention. Except for A4, which is the emphasized content of the present invention, the other device preparation methods are conventional preparation methods in the field without special instructions, and the materials are commercially available without special instructions, which specifically include the following steps:

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

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

[0059] A3. Prepare Cs by spin coating under nitrogen protection 0.05 MA 0.1 FA 0.85 Perovskite film, as the perovskite light absorbing layer.

[0060] A4. Prepare a post-treatment solution to which NMP is added, and treat the surface of the perovskite film described in A3:

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

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

[0063] A5, 25nm C was deposited on the sample obtained in A4 by evaporation method. 60 With 6nm BCP film, it serves as the electron transport layer of the device.

[0064] A6. Use the evaporation method to deposit a 100nm Ag film on the sample obtained in A5 as the top electrode of the device, and the device preparation is completed.

[0065] Example 2

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

[0067] Example 3

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

[0069] Example 4

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

[0071] Example 5

[0072] This embodiment provides a method for regulating the surface structure of perovskite based on NMP, and a related device preparation process. The specific operation steps are the same as those in Example 3, except that the post-treatment material used in step S1 is phenethylammonium bromide (PEABr) instead of 2-ThEAI.

[0073] Example 6

[0074] This embodiment provides a method for regulating the surface structure of perovskite based on NMP, and a related device preparation process. The specific operation steps are the same as those in Example 4, except that the post-treatment material used in step S1 is phenethylammonium bromide (PEABr) instead of 2-ThEAI.

[0075] Example 7

[0076] This embodiment provides a method for regulating the surface structure of perovskite based on NMP, and a related device preparation process. The specific operation steps are the same as those in Example 3, except that: the wide band gap perovskite used in step A3 of the device preparation is Cs 0.05 MA 0.22 FA 0.73 Pb(I 0.77 Br 0.23 )3; the volume ratio of NMP to IPA in step S1 is 1:250; C is evaporated in S1 60 Before that, an additional 1nm LiF film is evaporated.

[0077] Comparative Example 1

[0078] This embodiment provides a method for regulating the surface structure of perovskite based on NMP, and a related device preparation process. The specific operation steps are the same as those in Example 1, except that: no operation in steps S1 and S2 is performed.

[0079] Comparative Example 2

[0080] This embodiment provides a method for regulating the surface structure of perovskite based on NMP, and a related device preparation process. The specific operation steps are the same as those in Example 1, except that: the NMP addition operation in step S1 is not performed.

[0081] Comparative Example 3

[0082] This embodiment provides a method for regulating the surface structure of perovskite based on NMP, and a related device preparation process. The specific operation steps are the same as those in Example 5, except that: the NMP addition operation in step S1 is not performed.

[0083] Comparative Example 4

[0084] This embodiment provides a method for regulating the surface structure of perovskite based on NMP, and a related device preparation process. The specific operation steps are the same as those in Example 7, except that: no operation in steps S1 and S2 is performed.

[0085] Comparative Example 5

[0086] This embodiment provides a method for regulating the surface structure of perovskite based on NMP, and a related device preparation process. The specific operation steps are the same as those in Example 7, except that: the NMP addition operation in step S1 is not performed.

[0087] Figure 1It is a schematic diagram of the principles of conventional post-processing strategies, perovskite surface structure regulation strategies based on a small amount of perovskite complex solvent additives, and perovskite surface regulation strategies based on a large amount of perovskite complex solvent additives. The regulation range of conventional post-processing methods is mainly limited to the surface of perovskites, and it is difficult to efficiently eliminate defects inside the three-dimensional structure. Moreover, the two-dimensional structure covering layer often produced will form a serious quantum well effect, inhibiting the efficient transmission of carriers. If a small amount of perovskite complex solvent additives are used to interact with the perovskite surface, it will induce changes in the two-dimensional structure of the perovskite surface. The increase in the amount of perovskite complex solvent additives will lead 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. If a large amount of perovskite complex solvent additives are used to interact more strongly with the perovskite surface, it can more effectively induce a further increase in the n value, improve the quantum well effect, and at the same time facilitate the post-processing material structure to enter the three-dimensional perovskite bulk phase structure, thereby synergistically improving charge transport.

[0088] Figure 2 The fluorescence spectrum test results of the glass / perovskite samples of Comparative Examples 1-2 and Examples 1-3 are shown to characterize the evolution of low-dimensional structures and the non-radiative recombination of carriers in the perovskite film itself. The relevant experimental results are obtained based on NMP, a perovskite complex solvent additive, and are intended only for ease of understanding and are not used to limit the invention. The left figure is the test results of each sample in the 450-700nm band. Comparative Example 1 is a three-dimensional perovskite without any post-treatment, and no significant low-dimensional characteristic peaks appear in this band. Comparative Example 2 is a sample treated with a traditional post-treatment scheme, and the fluorescence spectrum shows a significant characteristic peak of a two-dimensional structure (n=1). The n value is too small, and the inhibitory effect on carrier transport is significant. In contrast, the test curve of Example 1 also shows a two-dimensional structural characteristic peak, but its peak position is further to the right than that of Comparative Example 2, indicating that the interaction between the perovskite complex solvent additive and the surface structure can indeed cause an increase in the n value (n=2). As the amount of the perovskite complex solvent additive is further increased, in Example 2, in addition to a characteristic peak in the range of 525-600nm, a characteristic peak (n=3) also appears in the range of 600-675nm, indicating that further increasing the amount of the perovskite complex solvent additive will cause the n value to shift to a higher value. For Example 3, when the amount of the perovskite complex solvent additive is further increased, it is difficult to observe a significant characteristic peak in the 450-750 band, and the curve corresponding to the low-dimensional structure near 700nm and the curve corresponding to the three-dimensional structure near 800nm ​​are highly integrated ( Figure 2 The above law can confirm that after adding different amounts of perovskite complex solvent additives, the fine layer structure of the low-dimensional structure on the surface of the perovskite film will change significantly. Figure 2 The right figure is the fluorescence spectrum test result of 450-975nm band. The characteristic peak of this band corresponds to the three-dimensional perovskite phase. The order of fluorescence peak intensity of each sample in this band is: Example 3> Example 2> Example 1> Comparative Example 2> Comparative Example 1. The above experimental results show that although the traditional post-treatment method can weaken and improve the non-radiative recombination of carriers, the method proposed in the present invention has a better improvement effect. Note that the above Figure 2 The left picture is only Figure 2 The right picture is a partial enlargement for easy observation and analysis.

[0089] In order to demonstrate the effect of the change in carrier transport behavior between the perovskite / charge transport layer, the present invention demonstrates the glass / perovskite / C 60 Fluorescence spectrum test results of samples (such as Figure 3 The order of the fluorescence peak intensity of each sample is: Comparative Example 1>Comparative Example 2>Example 3. Figure 2 and Figure 3 The test results show that although the traditional post-treatment method can improve the transport of carriers between the perovskite / charge transport layer, the improvement effect of the method proposed in the present invention is better.

[0090] In order to intuitively demonstrate the application value of the novel low-dimensional fine structure reconstruction method of the present invention, the performance of the perovskite solar cell devices prepared in accordance with Examples 1-7 and Comparative Examples 1-5 are analyzed below. Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 The JV curves and parameters of the perovskite solar cells of comparative examples 1, 2, 3, 4, and 5 are shown respectively. Fig. 9 , Fig.10 , Fig.11 , Fig.12 , Fig.13 , Fig.14 , Fig.15 The JV curves and parameters of the perovskite solar cells of Examples 1, 2, 3, 4, 5, 6, and 7 respectively. Figure 4-15 The test results are all under the conditions of solar simulator illumination (light intensity of 100mW cm -2 ) obtained, the following is a comparative analysis of the device performance under various conditions:

[0091] First, the perovskite complex solvent additive strategy proposed in the present invention can improve the photovoltaic performance of perovskite, and comparative example 1, comparative example 2, and examples 1-3 are analyzed as typical representatives. Compared with comparative example 1, although comparative example 2 without the use of the perovskite complex solvent additive can improve the photoelectric conversion efficiency of the device, the effect of improving the device efficiency of examples 1-3 based on the perovskite complex solvent additive strategy proposed in the present invention is better.

[0092] For different types of post-treatment materials, the perovskite complex solvent additive strategy proposed in the present invention also has the effect of improving device performance, as illustrated below: Compared with Comparative Example 2 and Examples 1-4, Comparative Example 3 and Examples 5-6 use different post-treatment materials. Comparative Example 3 shows a device performance that is better than Comparative Example 1, indicating that different post-treatment materials are also effective in improving device performance, but Examples 5-6 based on the post-treatment strategy of perovskite complex solvent additives are significantly more efficient, indicating that even if different post-treatment materials are selected, the effect of improving device performance based on the strategy proposed in the present invention is more significant.

[0093] The present invention can regulate the improvement effect of device performance by using different amounts of perovskite complex solvent additives, as illustrated below: Although Examples 1-4 use the same perovskite complex solvent additive, the amounts of perovskite complex solvent additives added are different, and the device performance improvement effects are different. When the volume ratio of the perovskite complex solvent additive to IPA increases from 0 to 1:125, the device performance improves accordingly. Similarly, the types of post-treatment materials and solvent additives used in Examples 5-6 are also the same, but the amounts of perovskite complex solvent additives added are different, and the device performance improvement effects are different. It is understandable that excessive introduction of perovskite complex solvent additives may cause adverse excessive dissolution and damage to the three-dimensional perovskite, resulting in deterioration of device performance. For example, when the volume ratio used in Example 4 is as high as 1:100, the device performance of Example 4 decreases compared to Example 3.

[0094] For the case of perovskites with different compositions, the novel strategy based on perovskite complex solvent additives described in the present invention can also achieve device performance improvement, as illustrated by the following examples: by analyzing comparative examples 4, 5 and embodiment 7, which have different perovskite components and the above-mentioned situations, it can be found that the performance of the perovskite solar cell in embodiment 7 is significantly higher than that of comparative examples 4 and 5.

[0095] In summary, the perovskite surface structure control method based on the perovskite complex solvent additive proposed in the present invention has multiple advantages: based on simply adding the perovskite complex solvent additive and adjusting the added concentration of the perovskite complex solvent additive, the n value of the two-dimensional structure can be controllably induced to change to varying degrees, thereby achieving a directional change in the corresponding low-dimensional fine structure, and the device performance can also change to varying degrees. For different post-treatment materials or different perovskites, the strategy proposed in the present invention can also effectively improve the photoelectric conversion efficiency of the corresponding photovoltaic.

[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 in the protection scope of the present invention.

Claims

1. A method for regulating the low-dimensional structure of the perovskite surface based on a perovskite complex solvent additive, characterized in that: The method for regulating the low-dimensional structure of the perovskite surface comprises the following steps: Step S1: adding a perovskite complex solvent additive to solution 1 to obtain solution 2; Step S2: using the solution 2 to perform low-dimensional structure control treatment on the surface of the original perovskite film to obtain a controlled perovskite film; in, The solution 1 at least includes reagent a and reagent b, The reagent a is characterized in that it can form a low-dimensional structure on the surface of the perovskite, including but not limited to at least one of phenethylammonium bromide, 2-thiopheneethylamine hydroiodide, phenethylammonium iodide, phenethylammonium chloride, 2-thiopheneethylamine hydrobromide, 2-thiopheneethylamine hydrochloride, benzylamine hydrochloride, benzylamine hydrobromide, benzylamine hydroiodide, benzamidine hydrochloride, benzamidine hydrobromide, benzamidine hydroiodide, 1,3-propylenediamine hydroiodide, 1,3-propylenediamine hydrobromide, 1,3-propylenediamine hydrochloride, cyclopropylformamidine hydrochloride, formamidine hydrobromide, guanidine iodide, and metformin; The reagent b is characterized in that it does not dissolve and destroy the perovskite, and includes but is not limited to at least one of isopropanol, n-butanol, chlorobenzene, acetonitrile, toluene, dichloromethane, chloroform, ether, ethyl acetate, γ-butyrolactone, anisole, methyl benzoate, and diethyl carbonate; The perovskite complexing solvent additive is characterized in that it can interact with the perovskite in a complexing manner, including but not limited to one or more of N-methylpyrrolidone (NMP), 1,3-dimethyl-2-imidazolidinone (DMI), 1,3-dimethyl-3,4,5,6-tetrahydro-2-pyrimidinone (DMPU), hexamethylphosphoric acid triamide (HMPA), γ-butyrolactone (GBL), tetramethylurea (TMU), and N-methylformamide (NMF); Preferably, the perovskite complexing solvent additive is N-methylpyrrolidone (NMP).

2. The method for regulating the low-dimensional structure of the perovskite surface according to 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 regulating the low-dimensional structure of the perovskite surface according to claim 1, characterized in that: In step S1, preferably, 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 regulating the low-dimensional structure of the perovskite surface according to 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; B is a divalent cation, including Pb 2+ Sn 2+ At least one of; X is a monovalent anion, including I - Br - , Cl - 、SCN - , at least one of formate ions.

5. The method for regulating the low-dimensional structure of the perovskite surface according to claim 1, characterized in that: In step S2, the control treatment method includes one or more of a doctor blade coating method, a slit coating method, a spin coating method, a screen printing method, an inkjet printing method or a metering rod coating method, so that the solution 2 is in contact with the surface of the original perovskite film.

6. The method for regulating the low-dimensional structure of the perovskite surface according to claim 1, characterized in that: Step S2 also includes annealing the original perovskite film after the regulation treatment at 50-150° C. for 1-30 minutes to obtain a regulated perovskite film.

7. A perovskite 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. Application of the regulated perovskite 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 film according to claim 7 in the field of semiconductor devices and photovoltaics.

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