Perovskite active layer film, preparation method thereof and perovskite solar cell

Abstract

The invention discloses a perovskite active layer film, a preparation method thereof and a perovskite solar cell, and belongs to the field of photovoltaic technology. The preparation method of the perovskite active layer film comprises the following steps: S1, mixing a perovskite active material and a solvent to obtain a perovskite precursor solution; the solvent comprises a first solvent which is a mixed solvent of N-methyl-2-pyrrolidone, dimethyl sulfoxide and N, N-dimethylformamide, and the first solvent, the dimethyl sulfoxide and the N, N-dimethylformamide are sequentially mixed according to the volume ratio of (1-10): (1-8): 100; and S2, coating the perovskite precursor solution on the surface of a substrate, carrying out vacuum flash evaporation, and then carrying out heating treatment to obtain the perovskite active layer film. The DMSO solvent in a specific proportion is introduced into the precursor solvent, and the proportion of the three solvents is controlled, so that growth of crystal grains in the perovskite active layer thin film can be obviously promoted, the perovskite crystal grain size and the crystal grain quality are improved, and the photoelectric conversion efficiency of the perovskite solar cell is further improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a perovskite active layer film and a preparation method thereof, and a perovskite solar cell. Background Art

[0002] Perovskite photovoltaics is an emerging photovoltaic technology that has developed rapidly in recent years. Thanks to the high defect tolerance and solution processability of perovskite photovoltaic materials, it is very suitable for the preparation of large-area photovoltaic modules. In recent years, the photoelectric conversion efficiency of perovskite solar cells has increased rapidly; currently, the photoelectric efficiency of laboratory-level small-area (less than 1 square centimeter) perovskite solar cells has exceeded 26%, the photoelectric efficiency of laboratory-level large-area (1 to 10 square centimeters) perovskite solar cells has exceeded 24%, the photoelectric efficiency of mini-module-level (10 to 1000 square centimeters) perovskite solar cells has exceeded 21%, and the photoelectric conversion efficiency of larger mass-production-level (greater than 1000 square centimeters) perovskite solar cells has exceeded 18%. In perovskite solar cells with a larger area (greater than 10 square centimeters), the perovskite active layer film is prepared by scraping or slit-coating the perovskite precursor solution on the substrate, assisted by post-processing.

[0003] At present, in perovskite solar cells with a larger area (greater than 10 square centimeters), the perovskite precursor generally uses a mixed solvent of DMF and NMP to dissolve the perovskite components. The perovskite film processed by this mixed solvent usually has small grains and low grain quality. Small grains lead to an increase in grain boundaries and defects at grain boundaries; low grain quality leads to a significant increase in defects within the grains. The increase in defects makes it impossible to further improve the photoelectric conversion efficiency of perovskite solar cells with a larger area (greater than 10 square centimeters). Summary of the invention

[0004] The main purpose of the present application is to provide a perovskite active layer film and a preparation method thereof and a perovskite solar cell, so as to solve the problems in the prior art that the perovskite active layer film has small grains, low grain quality, and many defects in the grains, which affect the photoelectric conversion efficiency.

[0005] In order to achieve the above object, according to one aspect of the present application, a method for preparing a perovskite active layer film is provided, comprising the steps of:

[0006] Step S1: mixing a perovskite active material and a solvent to obtain a perovskite precursor solution; wherein the solvent includes a first solvent; the first solvent is a mixed solvent of N-methyl-2-pyrrolidone, dimethyl sulfoxide and N,N-dimethylformamide, and the volume ratio of N-methyl-2-pyrrolidone, dimethyl sulfoxide and N,N-dimethylformamide is (1-10): (1-8): 100;

[0007] Step S2: coating the perovskite precursor solution on the surface of the substrate, vacuum flash evaporating and then heating to obtain a perovskite active layer film.

[0008] Furthermore, in step S1, the volume ratio of N-methyl-2-pyrrolidone, dimethyl sulfoxide and N,N-dimethylformamide is (3-7):(2-6):100; preferably (4-6):(3-5):100.

[0009] Furthermore, in step S1, the solvent further includes a second solvent; the second solvent is 1,3-dimethylpropyleneurea.

[0010] Furthermore, in step S1, the volume of the first solvent is 90% to 100% of the volume of the solvent, and the volume of the second solvent is 0% to 10% of the volume of the solvent.

[0011] Furthermore, the volume of the first solvent is 90% to 98% of the total volume of the solvent, and the volume of the second solvent is 2% to 10% of the total volume of the solvent.

[0012] Further, in step S1, the perovskite active material includes a first active material; the first active material is FAPbI3, and FA in FAPbI3 is NH2CHNH2.

[0013] Furthermore, the weight percentage of the first active material in the perovskite active material is 90% to 98%; furthermore, 92% to 98%.

[0014] Further, in step S1, the perovskite active material also includes a second active material; the second active material is ABX3; wherein A in ABX3 is selected from one or more of CH3NH3, NH3CH2NH3, C8H9NH3, Cs, Rb and K; B in ABX3 is selected from one or more of Pb, Sn and Ge; X in ABX3 is selected from one or more of F, Cl, Br and I.

[0015] Furthermore, the weight percentage of the second active material in the perovskite active material is 2% to 10%; furthermore, 2% to 8%.

[0016] Furthermore, in step S1, the molar concentration of the perovskite precursor solution is 0.1 to 2 mmol / mL; further 0.8 to 1.8 mmol / mL; further 1.4 to 1.6 mmol / mL.

[0017] Furthermore, in step S2, the perovskite precursor solution is coated on the surface of the substrate by blade coating or slit coating.

[0018] Furthermore, the temperature of the heating treatment is 80 to 180° C., and the time is 5 to 30 minutes.

[0019] Furthermore, the temperature of the heating treatment is 140 to 160° C., and the time is 15 to 25 minutes.

[0020] Furthermore, the vacuum degree of the vacuum flash evaporation is -0.045 to -0.08 MPa.

[0021] According to the second aspect of the present application, the above-mentioned perovskite active layer film is provided, which is prepared by the above-mentioned preparation method.

[0022] Furthermore, the thickness of the perovskite active layer film is 200 to 2000 nm.

[0023] Furthermore, the grain size of the perovskite active layer film is 1 to 2 μm.

[0024] According to a third aspect of the present application, a perovskite solar cell is provided, which is formed by laminating a conductive glass layer, an electron transport layer, a perovskite active layer, a hole transport layer and a metal electrode layer in sequence; wherein the perovskite active layer is the above-mentioned perovskite active layer film.

[0025] Furthermore, the conductive glass layer is selected from FTO conductive glass.

[0026] Furthermore, the electron transport layer is formed by coating tin dioxide on the surface of the conductive glass layer.

[0027] Furthermore, the hole transport layer is formed by coating 2,2',7,7'-tetrakis(N,N-dimethylamino)-9,9'-spirobifluorene on the surface of the perovskite active layer.

[0028] Furthermore, the metal electrode layer is a gold electrode layer.

[0029] According to a fourth aspect of the present application, a perovskite module device is provided, including a perovskite solar cell; the perovskite solar cell is the above-mentioned perovskite solar cell.

[0030] By applying the technical solution of the present application, a method for preparing a perovskite active layer film is provided. By introducing a specific proportion of DMSO solvent into the precursor solvent, the growth of grains in the perovskite active layer film is controlled, the perovskite grain size and grain quality are significantly improved, and the photoelectric conversion efficiency of the perovskite solar cell is thereby improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0032] Figure 1The SEM image of the perovskite active layer film prepared in Example 1 of the present application is shown;

[0033] Figure 2 A graph showing the photoelectric conversion efficiency of the perovskite micromodule device prepared in accordance with Example 1 of the present application is shown;

[0034] Figure 3 The SEM image of the perovskite active layer film prepared in Comparative Example 1 of the present application is shown;

[0035] Figure 4 A photoelectric conversion efficiency curve of the perovskite micromodule device prepared in accordance with Comparative Example 1 of the present application is shown. DETAILED DESCRIPTION

[0036] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] As mentioned in the background technology, when preparing perovskite solar cells with a larger area (greater than 10 square centimeters), a mixed solvent of DMF and NMP is used to dissolve the perovskite components. However, the perovskite film processed by this mixed solvent usually has small grains and low grain quality. The small grains lead to an increase in grain boundaries and a significant increase in defects at the grain boundaries. The low grain quality leads to a significant increase in defects within the grains. The increase in defects makes it impossible to further improve the photoelectric conversion efficiency of perovskite solar cells with a larger area (greater than 10 square centimeters).

[0038] Therefore, the present application provides a method for preparing a perovskite active layer film, comprising the following steps:

[0039] Step S1: mixing a perovskite active material and a solvent to obtain a perovskite precursor solution;

[0040] The solvent includes a first solvent; the first solvent is a mixed solvent of N,N-dimethylformamide, N-methyl-2-pyrrolidone and dimethyl sulfoxide; and the volume ratio of N-methyl-2-pyrrolidone, dimethyl sulfoxide and N,N-dimethylformamide is (1-10): (1-8): 100;

[0041] Step S2: coating the perovskite precursor solution on the surface of the substrate, vacuum flash evaporating and then heating to obtain a perovskite active layer film.

[0042] The present application introduces DMSO solvent into the precursor solvent and adjusts the specific ratio of the three solvents to adjust and control the growth process of grains in the perovskite active layer film, significantly improve the perovskite grain size and grain quality, and further effectively improve the photoelectric conversion efficiency of perovskite solar cells with a larger area (greater than 10 square centimeters).

[0043] In the solvents used in this application, DMSO and NMP will react with Pb in the precursor solute. 2+ An addition reaction occurs to promote the dissolution of the perovskite solute; most of the DMF can be evaporated by flash evaporation. Since NMP and DMSO have high melting points and are not easy to evaporate, NMP and DMSO can be gradually evaporated by heating annealing; and the content of NMP and DMSO added will affect the speed at which the perovskite crystals precipitate from the solvent, thereby affecting the size of the grain growth and the quality of the crystal; therefore, the ratio of the three solvents must be limited; the N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF) of the present application The volume ratio is (1-10): (1-8): 100, the volume of NMP is less than 10% of the volume of DMF, and the volume of DMSO is less than 8% of the volume of DMF. The DMSO solvent can improve the quality of grain growth, but when added in excess, it cannot be removed well in the subsequent solvent removal process and will affect the grain growth. If the amount of DMSO added is too small, the quality of grain growth cannot be effectively improved. Therefore, only when the three solvents are used in the above ratio can the quality of grain growth be better regulated, grain growth can be promoted, and internal defects of grains can be reduced, thereby promoting the photoelectric conversion efficiency of perovskite solar cells.

[0044] In some embodiments, in step S1, the volume ratio of N-methyl-2-pyrrolidone, dimethyl sulfoxide, and N,N-dimethylformamide in the first solvent is (3-7): (2-6): 100; further (4-6): (3-5): 100; for example 5:4:100.

[0045] By further optimizing the ratio between the three solvents, the present application can better regulate the grain growth quality, promote grain growth, reduce grain interface and internal defects, and further improve the photoelectric conversion efficiency of perovskite solar cells.

[0046] In some embodiments, in step S1, the solvent further comprises a second solvent; the second solvent is 1,3-dimethylpropyleneurea. The present application can further control the crystallization speed and grain size by adding the second solvent.

[0047] In some embodiments, in step S1, the volume of the first solvent is 90% to 100% of the total volume of the solvent; further 90% to 98%; for example, any value among 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100% or any range value between two of them.

[0048] The present application controls the volume content of the first solvent to be above 90%, ensuring that at least the usage of the three solvents NMP, DMF and DMSO must be sufficient to dissolve the active material and these three solvents are the main ones, thereby promoting the quality of grain growth.

[0049] In some embodiments, the volume of the second solvent is 0% to 10% of the total volume of the solvent; further 2% to 10%; for example, any value among 0, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or any range between two values.

[0050] The solvent of the present application is mainly composed of NMP, DMF and DMSO in a specific proportion, and a second solvent with an auxiliary effect can also be added, so that the quality of the grains can be further optimized on the basis of ensuring that the quality of the grains can be well controlled; too much content of the second solvent will affect the solvent viscosity.

[0051] In some embodiments, in step S1, the perovskite active material includes a first active material; the first active material is FAPbI3, and FA is NH2CHNH2.

[0052] The cation FA in the active material selected in this application has a lower band gap, excellent photoelectric properties and higher thermal stability, and has a better cubic perovskite lattice; more importantly, this type of perovskite active material has good solubility in solvents NMP, DMF and DMSO, and the matching of the active material and the solvent can further improve the grain growth process and promote the photoelectric conversion efficiency.

[0053] In some embodiments, in step S1, the perovskite active material further includes a second active material; the second active material is ABX3; wherein A in ABX3 is selected from one or more of CH3NH3, NH3CH2NH3, C8H9NH3, Cs, Rb and K; B in ABX3 is selected from one or more of Pb, Sn and Ge; X in ABX3 is selected from one or more of F, Cl, Br and I. In the present application, the crystal quality of the first active material is mainly regulated by the second active material.

[0054] In some embodiments, the weight percentage of the first active material in the perovskite active material is 90% to 98%; further 92% to 98%; for example, any value among 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or any range between two values.

[0055] The present application controls the proportion of the most matching active material FAPbI3 between 90% and 98%, thereby ensuring the matching solubility of the active material and the solvent in a specific proportion, as well as the good photoelectric performance, thermal stability and good lattice structure of the active material itself. A certain proportion of space can be reserved for adding components with other related functions, thereby further regulating the crystallization quality and photoelectric properties of the perovskite active layer.

[0056] In some embodiments, the weight percentage of the second active material in the perovskite active material is 2% to 10%; further 2% to 8%; for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or any range therebetween.

[0057] In the present application, the content of the second active material is controlled within the above ratio. In addition to ensuring the good photoelectric properties and grain structure of the perovskite active material FAPbI3, the band gap and crystal quality can be regulated within a certain range by adding a certain ratio of the second active material.

[0058] In some embodiments, in step S1, the molar concentration of the perovskite precursor solution is 0.1 to 2 mmol / mL; further 0.8 to 1.8 mmol / mL; and further 1.4 to 1.6 mmol / mL.

[0059] The present application controls the concentration of the perovskite precursor solvent within the above range, which has the advantages of suitable viscosity and good solubility, and can achieve an effective coating effect. Too high a concentration is not conducive to later processing, and too low a concentration cannot fully exert the performance of the perovskite active material.

[0060] In some embodiments, in step S2, the perovskite precursor solution is coated on the surface of the substrate by blade coating or slit coating. The perovskite precursor solution of the present application is suitable for the above coating method, and the coating effect is good.

[0061] In some embodiments, the heating treatment temperature is 80-180° C., and the time is 5-30 minutes; further, the heating treatment temperature is 140-160° C., and the time is 15-25 minutes.

[0062] The heating temperature and time adopted in the present application can promote the evaporation rate of NMP and DMSO, thereby obtaining a perovskite active layer film with good crystallinity and low defect concentration.

[0063] In some embodiments, the vacuum degree of the vacuum flash evaporation is -0.045 to -0.08 MPa. The present application adopts this vacuum degree to evaporate most of the DMF as much as possible.

[0064] According to the second aspect of the present application, a perovskite active layer film is provided, which is prepared by the above-mentioned preparation method.

[0065] In some embodiments, the thickness of the perovskite active layer film is 200-2000 nm.

[0066] The perovskite active layer film prepared in the present application has the above-mentioned thickness, and the active layer within this thickness range has good photoelectric conversion performance during use.

[0067] In some embodiments, the grain size of the perovskite active layer film is 1-2 μm.

[0068] The perovskite active layer film prepared in the present application has a relatively large grain size and high quality, reduces grain boundaries, and significantly reduces defects at grain boundaries and internal defects, which can significantly improve the photoelectric conversion efficiency of large-area (greater than 10 square centimeters) perovskite solar cells.

[0069] The present application can use the above-mentioned perovskite active layer to prepare the above-mentioned perovskite cell. The perovskite solar cell structure of the present application is the prior art, such as sequentially including a conductive glass layer, an electron transport layer (or a hole transport layer), a perovskite active layer, a hole transport layer (or an electron transport layer), a metal electrode layer, etc.; wherein the perovskite active layer can be prepared by the above-mentioned method of the present application, which can significantly improve the photoelectric conversion effect of the perovskite solar cell.

[0070] The present application can utilize the above-mentioned perovskite battery to form a perovskite module device.

[0071] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0072] The abbreviations and technical terms in this application are explained as follows:

[0073] DMF: Chinese name: N,N-dimethylformamide (DMF, CAS No. 68-12-2);

[0074] NMP: Chinese name: N-Methyl-2-pyrrolidone (NMP, CAS No. 872-50-4);

[0075] DMSO: Chinese name: Dimethylsulfoxide (DMSO, CAS No. 67-68-5);

[0076] DMPU: Chinese name: 1,3-dimethyl-tetrahydropyrimidin-2(1H)-one, CAS No. 7226-23-5;

[0077] SEM image: Scanning electron microscope image, which is used to show the morphology of the perovskite surface.

[0078] Example 1

[0079] A method for preparing a perovskite active layer film comprises the following steps:

[0080] Step S1: Mix the perovskite active material FAPbI3 (FA is NH2CHNH2) and the solvents NMP, DMSO, and DMF, with the volume ratio of NMP, DMSO, and DMF being 5:4:100, to prepare a perovskite precursor solution with a molar concentration of 1.5 mmol / mL;

[0081] Step S2: The perovskite precursor solution is coated on the substrate surface by scraping, and the excess solvent is removed by -0.045MPa vacuum flash evaporation, and the perovskite active layer film is obtained by heating at 150°C for 20 minutes. The SEM morphology is as follows: Figure 1 .

[0082] Example 2

[0083] A method for preparing a perovskite active layer film comprises the following steps:

[0084] Step S1: Mix the perovskite active material FAPbI3 (FA is NH2CHNH2) and the solvents NMP, DMSO and DMF; wherein the volume ratio of NMP, DMSO and DMF is 3:2:100, and prepare a perovskite precursor solution with a molar concentration of 1.8 mmol / mL;

[0085] Step S2: The perovskite precursor solution is coated on the surface of the substrate by scraping, and the excess solvent is removed by -0.05 MPa vacuum flash evaporation. The solution is heated at 120° C. for 30 minutes to obtain a perovskite active layer film, whose SEM morphology is similar to that of Example 1.

[0086] Example 3

[0087] A method for preparing a perovskite active layer film comprises the following steps:

[0088] Step S1: Mix the perovskite active material FAPbI3 (FA is NH2CHNH2) and the solvents NMP, DMSO and DMF; wherein the volume ratio of NMP, DMSO and DMF is 7:6:100, and prepare a perovskite precursor solution with a molar concentration of 1.2 mmol / mL;

[0089] Step S2: The perovskite precursor solution is coated on the surface of the substrate by scraping, and the excess solvent is removed by -0.06 MPa vacuum flash evaporation, and heated at a temperature of 160° C. for 20 minutes to obtain a perovskite active layer film; its SEM morphology is similar to that of Example 1.

[0090] Example 4

[0091] A method for preparing a perovskite active layer film comprises the following steps:

[0092] Step S1: Mix the perovskite active material FAPbI3 (FA is NH2CHNH2) and the solvents NMP, DMSO and DMF; wherein the volume ratio of NMP, DMSO and DMF is 10:8:100, and prepare a perovskite precursor solution with a molar concentration of 0.8 mmol / mL;

[0093] Step S2: The perovskite precursor solution is coated on the surface of the substrate by scraping, and the excess solvent is removed by -0.07 MPa vacuum flash evaporation, and the film is heated at 180° C. for 20 minutes to obtain a perovskite active layer film; its SEM morphology is similar to that of Example 1.

[0094] Example 5

[0095] A method for preparing a perovskite active layer film comprises the following steps:

[0096] Step S1: Mix the perovskite active material FAPbI3 (FA is NH2CHNH2) and the solvents NMP, DMSO, DMF, and DMPU; wherein the volume ratio of NMP, DMSO, and DMF is 5:4:100; the volume ratio of the total volume of NMP, DMSO, and DMF to the volume ratio of DMPU is 90:10; prepare a perovskite precursor solution with a molar concentration of 1.5 mmol / mL;

[0097] Step S2: The perovskite precursor solution is coated on the surface of the substrate by scraping, and the excess solvent is removed by -0.08 MPa vacuum flash evaporation, and the film is heated at 150° C. for 20 minutes to obtain a perovskite active layer film; its SEM morphology is similar to that of Example 1.

[0098] Example 6

[0099] A method for preparing a perovskite active layer film comprises the following steps:

[0100] Step S1: Mix the perovskite active materials FAPbI3 (FA is NH2CHNH2), MAPbI3 (MA is CH3NH3) and solvents NMP, DMSO and DMF; wherein the volume ratio of NMP, DMSO and DMF is 5:4:100; the weight ratio of FAPbI3 and MAPbI3 is 95:5; prepare a perovskite precursor solution with a molar concentration of 1.5 mmol / mL;

[0101] Step S2: The perovskite precursor solution is coated on the surface of the substrate by scraping, and the excess solvent is removed by -0.08 MPa vacuum flash evaporation, and the film is heated at 150° C. for 20 minutes to obtain a perovskite active layer film; its SEM morphology is similar to that of Example 1.

[0102] Comparative Example 1

[0103] A method for preparing a perovskite active layer film comprises the following steps:

[0104] Step S1: Mix the perovskite active material FAPbI3 (FA is NH2CHNH2) and a solvent, wherein the solvent is NMP and DMF, and the volume ratio between the two is 10:100, to prepare a perovskite precursor solution with a molar concentration of 1.5 mmol / mL;

[0105] Step S2: The perovskite precursor solution is coated on the substrate surface by a doctor blade method, and the excess solvent is removed by vacuum flash evaporation. The perovskite active layer film is heated at 150°C for 20 minutes to obtain the perovskite active layer film. The SEM morphology is as follows: Figure 3 .

[0106] Comparative Example 2

[0107] A method for preparing a perovskite active layer film comprises the following steps:

[0108] Step S1: Mix the perovskite active material FAPbI3 (FA is NH2CHNH2) and the solvents NMP, DMSO, and DMF, with the volume ratio of NMP, DMSO, and DMF being 10:0.5:100, and prepare a perovskite precursor solution with a molar concentration of 1.5 mmol / mL;

[0109] Step S2: coating the perovskite precursor solution on the surface of the substrate by scraping, removing excess solvent by -0.045 MPa vacuum flash evaporation, and heating at 150° C. for 20 minutes to obtain a perovskite active layer film.

[0110] Comparative Example 3

[0111] A method for preparing a perovskite active layer film comprises the following steps:

[0112] Step S1: Mix the perovskite active material FAPbI3 (FA is NH2CHNH2) and the solvents NMP, DMSO, and DMF, with the volume ratio of NMP, DMSO, and DMF being 8:10:100, to prepare a perovskite precursor solution with a molar concentration of 1.5 mmol / mL;

[0113] Step S2: coating the perovskite precursor solution on the surface of the substrate by scraping, removing excess solvent by -0.045 MPa vacuum flash evaporation, and heating at 150° C. for 20 minutes to obtain a perovskite active layer film.

[0114] Application Examples

[0115] A perovskite solar cell, the structure of which comprises in sequence: a conductive glass layer (FTO), an electron transport layer (formed by coating tin dioxide on the surface of the conductive glass layer), a perovskite active layer (the perovskite precursor solution prepared in Example 1 is coated on the surface of the electron transport layer, and the perovskite active layer is formed after vacuum flash evaporation and heat treatment), a hole transport layer (formed by coating 2,2',7,7'-tetrakis(N,N-dimethylamino)-9,9'-spirobifluorene on the surface of the perovskite active layer), and a metal electrode layer (gold); wherein the perovskite active layer can be replaced by the perovskite active layer films of Examples 1 to 6 and Comparative Examples 1 to 3, respectively; and 10 different perovskite solar cells are obtained respectively.

[0116] The perovskite solar cells prepared in accordance with Examples 1 to 6 and Comparative Examples 1 to 3 (5 cells of the same type constitute one module) were respectively selected to make perovskite micro-module devices, and their photoelectric properties were tested.

[0117] The test method is: under room temperature, using a 3A solar simulator at 100mW / cm 2 The photoelectric conversion efficiency of the micro-modules prepared in the embodiment and the comparative example was tested under different light intensities.

[0118] Table 1

[0119]

[0120] From the test results in Table 1, it can be seen that the grain size of the perovskite active layer prepared in Examples 1 to 6 of the present application is concentrated in the range of 1 to 2 μm; the grain size of the perovskite active layer prepared in Comparative Example 1 is about 200 to 300 nm; Figure 1 and Figure 3As shown, it is obvious that the grain size in the perovskite active layer film prepared in the present application is significantly larger than that of the comparative example by about 3 to 10 times; this indicates that the present application can indeed promote grain enlargement, reduce grain boundaries and their internal defects, and improve grain quality by introducing a third solvent, dimethyl sulfoxide (DMSO), and controlling the volume ratio of N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF) to (1 to 10): (1 to 8): 100.

[0121] like Figure 2 and Figure 4 By comparing the photoelectric conversion efficiency of solar cells prepared with the perovskite active layer films of Example 1 and Comparative Example 1, the photoelectric conversion efficiency of the present application is 20.81%, and the photoelectric conversion efficiency of the comparative example is about 17.8%, and the photoelectric conversion efficiency of the present application is about 3% higher than that of the comparative example; it indicates that the present application can improve the grain quality and thus significantly improve the photoelectric conversion efficiency of the perovskite active layer by introducing a third solvent, dimethyl sulfoxide (DMSO), and controlling the volume ratio of N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF) to (1-10): (1-8): 100.

[0122] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.

[0123] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a perovskite active layer film, characterized in that: The preparation method comprises the following steps: Step S1: mixing a perovskite active material and a solvent to obtain a perovskite precursor solution; wherein the solvent includes a first solvent; the first solvent is a mixed solvent of N-methyl-2-pyrrolidone, dimethyl sulfoxide and N,N-dimethylformamide, and the volume ratio of the N-methyl-2-pyrrolidone, the dimethyl sulfoxide and the N,N-dimethylformamide is (1-10): (1-8): 100; Step S2: coating the perovskite precursor solution on the surface of the substrate, vacuum flash evaporating the solution and then heating it to obtain the perovskite active layer film.

2. The method for preparing the perovskite active layer film according to claim 1, characterized in that: In the step S1, the volume ratio of the N-methyl-2-pyrrolidone, the dimethyl sulfoxide and the N,N-dimethylformamide is (3-7): (2-6): 100; preferably (4-6): (3-5): 100; And / or, in step S1, the solvent further includes a second solvent; the second solvent is 1,3-dimethylpropyleneurea.

3. The method for preparing the perovskite active layer film according to claim 2, characterized in that: In the step S1, the volume of the first solvent is 90% to 100% of the total volume of the solvent, and the volume of the second solvent is 0% to 10% of the total volume of the solvent; Preferably, the volume of the first solvent is 90% to 98% of the total volume of the solvent, and the volume of the second solvent is 2% to 10% of the total volume of the solvent.

4. The method for preparing a perovskite active layer film according to any one of claims 1 to 3, characterized in that: In the step S1, the perovskite active material includes a first active material; the first active material is FAPbI3, and FA in the FAPbI3 is NH2CHNH2; Preferably, the weight percentage of the first active material in the perovskite active material is 90% to 98%, preferably 92% to 98%.

5. The method for preparing a perovskite active layer film according to any one of claims 1 to 4, characterized in that: In the step S1, the perovskite active material further includes a second active material; the second active material is ABX3; Wherein, A in ABX3 is selected from one or more of CH3NH3, NH3CH2NH3, C8H9NH3, Cs, Rb and K; B in the ABX3 is selected from one or more of Pb, Sn and Ge; X in the ABX3 is selected from one or more of F, Cl, Br and I; Preferably, the weight percentage of the second active material in the perovskite active material is 2% to 10%, and more preferably 2% to 8%.

6. The method for preparing a perovskite active layer film according to any one of claims 1 to 5, characterized in that: In step S1, the molar concentration of the perovskite precursor solution is 0.1 to 2 mmol / mL; preferably 0.8 to 1.8 mmol / mL; more preferably 1.4 to 1.6 mmol / mL; and / or, in the step S2, the perovskite precursor solution is coated on the surface of the substrate by blade coating or slit coating; And / or, the heating treatment temperature is 80-180°C and the time is 5-30 minutes; Preferably, the temperature of the heating treatment is 140-160°C and the time is 15-25 minutes; And / or, the vacuum degree of the vacuum flash evaporation is -0.045 to -0.08 MPa.

7. A perovskite active layer film, characterized in that: The perovskite active layer film is prepared by the preparation method described in any one of claims 1 to 6.

8. The perovskite active layer film according to claim 7, characterized in that: The thickness of the perovskite active layer film is 200-2000 nm; and / or the grain size of the perovskite active layer film is 1-2 μm.

9. A perovskite solar cell, characterized in that: The perovskite solar cell is formed by laminating a conductive glass layer, an electron transport layer, a perovskite active layer, a hole transport layer and a metal electrode layer in sequence; wherein the perovskite active layer is the perovskite active layer film according to claim 7 or 8; Preferably, the conductive glass layer is FTO conductive glass; Preferably, the electron transport layer is formed by coating tin dioxide on the surface of the conductive glass layer; Preferably, the hole transport layer is formed by coating 2,2',7,7'-tetrakis(N,N-dimethylamino)-9,9'-spirobifluorene on the surface of the perovskite active layer; Preferably, the metal electrode layer is a gold electrode layer.

10. A perovskite module device, comprising a perovskite solar cell, characterized in that: The perovskite solar cell is the perovskite solar cell according to claim 9.

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