Perovskite solution, perovskite thin film, preparation method of perovskite thin film and photovoltaic device

Abstract

The invention provides a perovskite solution, a perovskite thin film, a preparation method of the perovskite thin film and a photovoltaic device, the perovskite solution comprises a precursor solution and an amino acid additive, and the concentration of the amino acid additive in the perovskite solution is 0.001-0.1 mmol / mL; the amino acid additive comprises any one or a combination of at least two of histidine, a histidine derivative, aspartic acid and an aspartic acid derivative. According to the invention, the influence of air moisture can be avoided, the stability is high, and a photovoltaic device with high photoelectric conversion efficiency can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries and relates to a perovskite solution, a perovskite film and a preparation method thereof and a photovoltaic device. Background Art

[0002] Solution-processed halide perovskite semiconductors (hereinafter referred to as perovskites) are mainly used in the photovoltaic field. At present, the laboratory photoelectric efficiency of small-area nitrogen atmosphere perovskite solar cells has approached the theoretical limit of 30%, showing its important significance for sustainable development and application. Perovskite photovoltaic cell modules have the advantages of rapid production, high efficiency, and low cost.

[0003] The preparation of perovskite film needs to be carried out in an inert gas environment (such as nitrogen), which places high demands on the preparation conditions, that is, it is necessary to assemble expensive nitrogen systems and equipment, and it takes up a certain amount of space. If the nitrogen environment is removed and the perovskite film is assembled in the air, the photoelectric conversion efficiency of the device will decrease and the stability will deteriorate due to the easy phase change of its water vapor. Therefore, the key to preparing perovskite solar cell components in the air is how to reduce the impact of moisture on the perovskite film during the preparation process.

[0004] Defect passivation is an optimization method that can be applied to all layers of perovskite devices, mainly by reducing the activity of defect sites in the material to improve the performance of the battery. Generally speaking, crystal defects generated during the battery preparation process may become the center of carrier recombination, reducing the efficiency of the device, and it is also easy to become the starting point for the device to begin to deteriorate.

[0005] Therefore, while reducing the impact of moisture on perovskite films, it is also necessary to ensure the efficiency of photovoltaic devices. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a perovskite solution, a perovskite film and a preparation method thereof, and a photovoltaic device, which can avoid the influence of air moisture and obtain an efficient and stable photovoltaic device.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a perovskite solution, comprising a precursor solution and an amino acid additive, wherein the concentration of the amino acid additive in the perovskite solution is 0.001 to 0.1 mmol / mL; the amino acid additive comprises any one of histidine, histidine derivatives, aspartic acid and aspartic acid derivatives, or a combination of at least two thereof.

[0009] The concentration of the amino acid additive can be 0.001mmol / mL, 0.002mmol / mL, 0.005mmol / mL, 0.01mmol / mL, 0.015mmol / mL, 0.02mmol / mL, 0.025mmol / mL, 0.03mmol / mL, 0.035mmol / mL, 0.04mmol / mL, 0.045mmol / mL, 0.05mmol / mL, 0.055mmol / mL, 0.06mmol / mL, 0.065mmol / mL, 0.07mmol / mL, 0.075mmol / mL, 0.08mmol / mL, 0.085mmol / mL, 0.09mmol / mL, 0.095mmol / mL or 0.1mmol / mL, but is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable.

[0010] The present invention can prevent the influence of moisture in the air on the perovskite by adding an amino acid additive to the perovskite precursor, avoid the dependence on the nitrogen environment in the traditional preparation process, and make it suitable for perovskite precursors with different band gaps by adjusting the addition amount of the amino acid additive. It is also beneficial to increase the grain size of the perovskite microcrystals, effectively reduce the defect density, and further improve the efficiency of the perovskite component, thereby ensuring the feasibility of large-scale preparation and industrial application of perovskite films.

[0011] As a preferred technical solution of the present invention, the precursor solution includes a perovskite precursor and an organic solvent.

[0012] Preferably, the general formula of the perovskite precursor is ABX3;

[0013] wherein A is a combination of at least two of cesium, methylamino or methylamino;

[0014] B is lead;

[0015] X is iodine and / or bromine.

[0016] Preferably, in the perovskite solution, the concentration of the perovskite precursor is 0.8 to 1.4 mmol / mL, for example, it can be 0.8 mmol / mL, 0.85 mmol / mL, 0.9 mmol / mL, 0.95 mmol / mL, 1 mmol / mL, 1.05 mmol / mL, 1.2 mmol / mL, 1.25 mmol / mL, 1.3 mmol / mL, 1.35 mmol / mL or 1.4 mmol / mL, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, the organic solvent comprises any one of dimethyl sulfoxide, 2-methoxyethanol, N,N-dimethylformamide, N-methylpyrrolidone and acetonitrile, or a combination of at least two thereof, wherein typical but non-limiting combinations are: a combination of dimethyl sulfoxide and 2-methoxyethanol, a combination of dimethyl sulfoxide, 2-methoxyethanol and N,N-dimethylformamide, a combination of N,N-dimethylformamide, N-methylpyrrolidone and acetonitrile, a combination of dimethyl sulfoxide, N,N-dimethylformamide and N-methylpyrrolidone, a combination of dimethyl sulfoxide, N,N-dimethylformamide and acetonitrile, and the like.

[0018] As a preferred technical solution of the present invention, the amino acid additive includes any one of L-histidine, D-histidine, DL-histidine, L-aspartic acid, D-aspartic acid, DL-aspartic acid, histidine derivatives and aspartic acid derivatives, or a combination of at least two of them, wherein typical but non-limiting combinations are: a combination of L-histidine and D-histidine, a combination of DL-histidine and a histidine derivative, a combination of L-histidine, D-histidine and DL-histidine, a combination of L-histidine, D-histidine and a histidine derivative, a combination of L-aspartic acid and D-aspartic acid, a combination of DL-aspartic acid and an aspartic acid derivative, a combination of L-aspartic acid, D-aspartic acid and DL-aspartic acid, and a combination of L-aspartic acid, D-aspartic acid and an aspartic acid derivative.

[0019] In a second aspect, the present invention provides a method for preparing the perovskite solution according to the first aspect, the preparation method comprising: stirring and mixing the precursor solution and the amino acid additive.

[0020] As a preferred technical solution of the present invention, the stirring and mixing temperature is 35-50°C, for example, it can be 35°C, 36°C, 38°C, 40°C, 42°C, 43°C, 45°C, 46°C, 48°C or 50°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, the stirring and mixing speed is 650-850rpm / min, for example, it can be 650rpm / min, 660rpm / min, 680rpm / min, 700rpm / min, 730rpm / min, 750rpm / min, 760rpm / min, 780rpm / min, 800rpm / min, 820rpm / min, 830rpm / min or 850rpm / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, the stirring and mixing time is 300 to 480 min, for example, it can be 300 min, 320 min, 350 min, 360 min, 380 min, 400 min, 420 min, 430 min, 450 min, 460 min or 480 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] In a third aspect, the present invention provides a method for preparing a perovskite film, the preparation method comprising:

[0024] The perovskite solution described in the first aspect is coated on the surface of the substrate during the air blowing treatment, and then heat treated to obtain a perovskite film.

[0025] The present invention performs air blowing treatment while coating the perovskite solution to volatilize the solvent once and accelerate the film formation speed of the perovskite, and then performs heat treatment to volatilize the solvent for a second time to remove the residual solvent and assist the nucleation and growth of the perovskite crystals to form a dense and uniform perovskite polycrystalline film.

[0026] It should be noted that the substrate used in the preparation process of the present invention is only used as a support carrier for coating the perovskite solution, and is not a part of the perovskite film. After the heat treatment is completed, the perovskite film needs to be separated from the substrate. However, when the conductive substrate required by the photovoltaic device is directly used as the substrate, since the conductive substrate is a component of the photovoltaic device, there is no need to remove the perovskite film.

[0027] As a preferred technical solution of the present invention, the coating includes blade coating and / or slit coating.

[0028] The scraper coating described in the present invention is a process well known to those skilled in the art, in which a scraper is used to uniformly cover a perovskite solution on a substrate at a certain speed to form a coating. The slit coating described in the present invention is a process well known to those skilled in the art, in which a slit coater is used to continuously discharge a perovskite solution from a slit of a coating die head, and a substrate is passed under the slit, so that the perovskite solution discharged from the slit can be uniformly covered on the substrate to form a coating. The present invention does not specifically limit the type, structure and size of the scraper and the slit coater, and those skilled in the art can select a commonly used scraper or slit coater according to actual conditions.

[0029] Preferably, the coating speed is 20 to 30 mm / s, for example, it can be 20 mm / s, 21 mm / s, 22 mm / s, 23 mm / s, 24 mm / s, 25 mm / s, 26 mm / s, 27 mm / s, 28 mm / s, 29 mm / s or 30 mm / s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, nitrogen is used in the gas blowing treatment.

[0031] Preferably, the pressure of the air blowing treatment is 0.2-0.6 MPa, for example, it can be 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa, 0.4 MPa, 0.45 MPa, 0.5 MPa, 0.55 MPa or 0.6 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the temperature of the heat treatment is 100-150°C, for example, it can be 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, the heat treatment time is 10 to 20 min, for example, it can be 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min or 20 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] As a preferred technical solution of the present invention, the preparation method further comprises: performing a vacuum drying treatment after completing the coating and before the heat treatment.

[0035] Preferably, the vacuum degree of the vacuum drying treatment is 8 to 12 Pa, for example, it can be 8Pa, 8.5Pa, 9Pa, 9.5Pa, 10Pa, 10.5Pa, 11Pa, 11.5Pa or 12Pa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the temperature of the vacuum drying treatment is room temperature.

[0037] Preferably, the vacuum drying treatment time is 45 to 70 seconds, for example, it can be 45 seconds, 48 ​​seconds, 50 seconds, 52 seconds, 55 seconds, 58 seconds, 60 seconds, 63 seconds, 65 seconds, 68 seconds or 70 seconds, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] In a fourth aspect, the present invention provides a perovskite film, wherein the perovskite film is prepared by the method for preparing the perovskite film described in the third aspect.

[0039] The perovskite film of the present invention has a dense and uniform appearance, low defect density, strong resistance to external moisture erosion, and high stability, which is beneficial to improving the photoelectric conversion efficiency of the perovskite.

[0040] The average particle size of the grains in the perovskite film is 800-1000nm, for example, it can be 800nm, 820nm, 840nm, 850nm, 880nm, 900nm, 920nm, 950nm, 960nm, 980nm or 1000nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] The perovskite microcrystals in the perovskite film of the present invention have large grain sizes and excellent crystal plane orientation, thereby effectively reducing the film defect density.

[0042] Preferably, the thickness of the perovskite film is 500-700 nm, for example, it can be 500 nm, 520 nm, 530 nm, 550 nm, 580 nm, 600 nm, 620 nm, 650 nm, 660 nm, 680 nm or 700 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] In a fifth aspect, the present invention provides a photovoltaic device, comprising a conductive substrate, a first transmission layer, a perovskite film, a second transmission layer and an electrode layer stacked in sequence, wherein the perovskite film is prepared by the method for preparing the perovskite film described in the third aspect, or by the perovskite film described in the fourth aspect.

[0044] It should be noted that the photovoltaic device in the present invention can be a single-section perovskite photovoltaic device or a multi-section perovskite photovoltaic device.

[0045] In order to help those skilled in the art better understand the overall technical solution and working process of the present invention, the present invention exemplarily provides the following specific preparation method for a single-cell photovoltaic device, the preparation method comprising:

[0046] (1) mixing a precursor solution with an amino acid additive to prepare a perovskite solution;

[0047] (2) forming a first transmission layer on the surface of a conductive substrate by a vacuum deposition method and / or an atomic deposition method;

[0048] (3) coating the perovskite solution on the surface of the first transmission layer to form a perovskite film;

[0049] (4) forming a second transport layer on the surface of the perovskite film by vacuum deposition and / or atomic deposition;

[0050] (5) forming an electrode layer on the surface of the second transmission layer by thermal evaporation;

[0051] (6) Packaging is performed in an air environment to obtain a photovoltaic device.

[0052] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] The present invention provides a perovskite solution, a perovskite film, a preparation method thereof, and a photovoltaic device, which can prevent moisture in the air from affecting the perovskite and avoid dependence on a nitrogen environment in a traditional preparation process. The perovskite microcrystals have large grains, which reduces the defect density, further improving the efficiency of the perovskite component and ensuring the feasibility of large-area preparation and industrial application of the perovskite film. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A schematic diagram of the structure of a photovoltaic device provided in Example 1 of the present invention;

[0056] Figure 2 This is a scanning electron microscope image of the perovskite film provided in Example 1 of the present invention;

[0057] Figure 3 The X-ray diffraction pattern of the perovskite film provided in Example 1 of the present invention;

[0058] Figure 4 This is the current-voltage curve of the perovskite film provided in Example 1 of the present invention.

[0059] Among them, 1 is a conductive substrate; 10 is a transparent glass substrate; 11 is an ITO conductive layer; 2 is a hole transport layer; 3 is a perovskite film; 4 is a first electron transport layer; 5 is a second electron transport layer; 6 is an electrode layer; 7 is a first scribed line; 8 is a second scribed line; 9 is a third scribed line. DETAILED DESCRIPTION

[0060] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0061] In a specific embodiment, the present invention provides a perovskite solution, comprising a precursor solution and an amino acid additive, wherein the concentration of the amino acid additive in the perovskite solution is 0.001 to 0.1 mmol / mL; the amino acid additive comprises any one of histidine, histidine derivatives, aspartic acid and aspartic acid derivatives, or a combination of at least two thereof.

[0062] In some embodiments, the precursor solution includes a perovskite precursor and an organic solvent.

[0063] Specifically, the general formula of the perovskite precursor is ABX3, wherein A is a combination of at least two of cesium, methylamino or methylamine, B is lead, and X is iodine and / or bromine. In the perovskite solution, the concentration of the perovskite precursor is 0.8 to 1.4 mmol / mL; the organic solvent includes any one of dimethyl sulfoxide, 2-methoxyethanol, N,N-dimethylformamide, N-methylpyrrolidone and acetonitrile, or a combination of at least two of them.

[0064] In some embodiments, the amino acid additive includes any one of L-histidine, D-histidine, DL-histidine, L-aspartic acid, D-aspartic acid, DL-aspartic acid, histidine derivatives and aspartic acid derivatives, or a combination of at least two thereof.

[0065] In a specific embodiment, the present invention provides a method for preparing a perovskite solution according to a specific embodiment, and the preparation method comprises: stirring and mixing a precursor solution and an amino acid additive.

[0066] In some embodiments, the stirring and mixing temperature is 35 to 50° C., the stirring and mixing speed is 650 to 850 rpm / min, and the stirring and mixing time is 300 to 480 min.

[0067] In another specific embodiment, the present invention provides a method for preparing a perovskite film, the preparation method comprising:

[0068] The perovskite solution described in one specific embodiment is coated on the surface of the substrate during the air blowing treatment, and then heat treated to obtain the perovskite film.

[0069] In some embodiments, the method for preparing the perovskite film specifically comprises the following steps:

[0070] S1: coating the perovskite solution on the surface of the substrate by blade coating or slit coating, and performing air blowing treatment at the same time to volatilize the organic solvent in the precursor solution, wherein the coating speed is 20-30 mm / s, and the air blowing treatment uses nitrogen at a pressure of 0.2-0.6 MPa;

[0071] S2: After coating, vacuum drying is performed. The vacuum degree of vacuum drying is 8-12 Pa, the temperature is room temperature, and the time is 45-70 seconds.

[0072] S3: Then, heat treatment is performed to remove residual organic solvent and assist nucleation and growth of perovskite crystals to obtain a perovskite film, wherein the heat treatment temperature is 100-150° C. and the time is 10-20 min.

[0073] In one specific embodiment, the present invention provides a perovskite film, and the perovskite film is prepared by the preparation method of the perovskite film provided by another specific embodiment.

[0074] Specifically, the thickness of the perovskite film is 500-700 nm, and the average grain size of the crystal grains in the perovskite film is 800-1000 nm.

[0075] In another specific embodiment, the present invention provides a photovoltaic device, comprising a conductive substrate, a first transmission layer, a perovskite film, a second transmission layer and an electrode layer stacked in sequence, wherein the perovskite film is obtained by the preparation method of the perovskite film described in another specific embodiment, or by using the perovskite film described in a specific embodiment.

[0076] When the photovoltaic device described in the present invention is a single-section perovskite photovoltaic device, it includes a conductive substrate, a first transmission layer, a perovskite film, a second transmission layer and an electrode layer stacked in sequence, and the outer surface of the electrode layer is vacuum laminated with a backplane glass for packaging.

[0077] The photovoltaic device described in the present invention may also be a multi-section perovskite photovoltaic device, and a tunneling layer well known to those skilled in the art is provided between two adjacent sections.

[0078] Exemplarily, when the photovoltaic device is a dual-section perovskite photovoltaic device, it includes a conductive substrate, a first transmission layer I, a narrow-bandgap perovskite film, a second transmission layer I, a tunneling layer, a first transmission layer II, a wide-bandgap perovskite film, a second transmission layer II and an electrode layer stacked in sequence, and the outer surface of the electrode layer is vacuum laminated with a backplane glass for packaging.

[0079] Exemplarily, when the photovoltaic device is a three-section perovskite photovoltaic device, it includes a conductive substrate, a first transmission layer I, a narrow-bandgap perovskite film, a second transmission layer I, a tunneling layer I, a first transmission layer II, a medium-bandgap perovskite film, a second transmission layer II, a tunneling layer II, a first transmission layer III, a wide-bandgap perovskite film, a second transmission layer III and an electrode layer stacked in sequence, and the outer surface of the electrode layer is vacuum-laminated with a backplane glass for encapsulation.

[0080] The conductive substrate in the present invention is composed of a transparent glass substrate and a conductive layer deposited on the surface of the transparent glass, wherein the conductive layer includes but is not limited to an ITO layer, a FTO layer or an AZO layer known to those skilled in the art. The present invention does not specifically limit the size of the conductive substrate, and those skilled in the art can adjust it according to actual conditions. In order to improve the overall electrical properties and surface physical properties, the conductive substrate also needs to be cleaned. For example, the cleaning process adopts any one or a combination of at least two of ultrasonic cleaning, cleaning liquid cleaning and online surface cleaning commonly used in the art, and the present invention does not specifically limit this.

[0081] The first transport layer in the present invention is a hole transport layer, and the present invention specifically defines its material, including but not limited to nickel oxide, NiO X , CuSCN, CuI, V2O5, Cu2O. The thickness of the hole transport layer is 25-45 nm.

[0082] The perovskite film of the present invention is added with an amino acid additive, which can still maintain high stability in an air environment and prevent the perovskite from being corroded by moisture in the air. The thickness of the perovskite film is 500 to 700 nm. In addition, the present invention has strong applicability and can be applied to photovoltaic modules with a wide band gap range, for example, it can be used in an inverse perovskite photovoltaic device with a band gap range of 1.39 to 3.24 eV.

[0083] The second transport layer in the present invention is an electron transport layer, and the present invention does not specifically limit its material, including but not limited to one or a combination of at least two of C60, SnO2, TiO2, ZnO2, fullerene or fullerene derivatives known to those skilled in the art. The thickness of the second transport layer is 33 to 50 nm. The number of layers of the electron transport layer can be one layer or two layers. When two layers of electron transport layers are used, the two are independent of each other and do not interfere with each other, and the materials of the two adjacent electron transport layers may be different. Exemplarily, the electron transport layer can be a combination of a C60 layer and a SnO2 layer, and the thickness of the C60 layer is 25 to 35 nm, and the thickness of the SnO2 layer is 8 to 15 nm.

[0084] The electrode layer in the present invention includes but is not limited to any one of Ag, Au, Cu, Al, ITO, FTO, IZO, AZO, IWO, GZO, IGZO or silver nanowires. The thickness of the electrode layer is 100-200 nm.

[0085] The method for preparing a photovoltaic device provided by the present invention comprises the following steps:

[0086] (1) using a laser to scribble a conductive substrate to form a first scribing line P1, so that the first scribing line P1 penetrates the conductive layer of the conductive substrate;

[0087] (2) placing the conductive substrate in step (1) in an isopropanol cleaning solution and ultrasonically cleaning it for 20 to 40 minutes. After the ultrasonic cleaning is completed, drying it with nitrogen gas, and then performing an oxygen plasma surface treatment for 45 to 100 seconds to complete the cleaning of the conductive substrate;

[0088] (3) depositing a hole transport layer on the conductive substrate of step (2) by an atomic deposition method;

[0089] (4) mixing the precursor solution with the amino acid additive to prepare a perovskite solution, and forming a perovskite film on the surface of the first transport layer using a method for preparing a perovskite film in a specific embodiment;

[0090] (5) forming a second transmission layer on the surface of the perovskite film by vacuum deposition and / or atomic deposition, and then using a laser to scribe a first scribe line P2, so that the first scribe line P2 sequentially passes through the second transmission layer, the perovskite film and the first transmission layer;

[0091] (6) forming an electrode layer on the surface of the second transmission layer by thermal evaporation, and then using a laser to scribe a first scribe line P3, so that the first scribe line P3 sequentially passes through the electrode layer, the second transmission layer, the perovskite film and the first transmission layer;

[0092] (7) Packaging is performed in an air environment to obtain a photovoltaic device.

[0093] Example 1

[0094] This embodiment provides a photovoltaic device, such as Figure 1 As shown, it includes a conductive substrate 1, a hole transport layer 2, a perovskite film 3, a first electron transport layer 4, a second electron transport layer 5 and an electrode layer 6 which are stacked in sequence. The conductive substrate 1 adopts a transparent glass substrate 10 of 10×10 cm, and an ITO conductive layer 11 is arranged on the surface of the transparent glass substrate 10; the hole transport layer 2 adopts nickel oxide with a thickness of 30 nm; the perovskite film 3 adopts an inverse perovskite absorption layer with a band gap of 1.55 eV and a thickness of 600 nm; the first electron transport layer 4 adopts C60 with a thickness of 30 nm; the second electron transport layer 5 adopts SnO2 with a thickness of 12 nm; and the electrode layer 6 adopts Cu with a thickness of 150 nm.

[0095] The method for preparing a photovoltaic device provided in this embodiment specifically comprises the following steps:

[0096] (1) using a laser to scribe the conductive substrate 1 to form a first scribe line P1, so that the first scribe line P1 passes through the conductive layer 11 of the conductive substrate 1;

[0097] (2) placing the conductive substrate 1 in step (1) in an isopropanol cleaning solution and ultrasonically cleaning it for 30 minutes. After the ultrasonic cleaning is completed, drying it with nitrogen gas, and then performing an oxygen plasma surface treatment for 60 seconds to complete the cleaning of the conductive substrate 1;

[0098] (3) depositing nickel oxide on the conductive substrate of step (2) by an atomic deposition method to form a hole transport layer 2;

[0099] (4) The perovskite precursor FA 0.95 Cs 0.05 PbI 2.5 Br 0.5 , DL-histidine and N,N-dimethylformamide were mixed, and stirred at 800 rpm / min for 300 min at 40° C. to obtain a perovskite solution, wherein the concentration of the perovskite precursor was 1.15 mol / L, and the concentration of DL-histidine was 0.02 mol / L;

[0100] (5) coating the perovskite solution on the surface of the conductive substrate by scraping at a scraping speed of 25 mm / s in an air environment, and blowing nitrogen at a pressure of 0.6 MPa to volatilize the organic solvent in the precursor solution; after coating, vacuum drying was performed for 60 seconds at room temperature and a vacuum degree of 10 Pa; then heat treatment was performed at 125° C. for 15 minutes to remove the residual organic solvent and assist the nucleation and growth of perovskite crystals to obtain a perovskite film 3;

[0101] (6) forming a C60 layer on the surface of the perovskite film 3 by a vacuum deposition method, and then forming a SnO2 layer on the surface of the C60 layer by an atomic deposition method;

[0102] (7) Then, a laser is used to scribe a first scribe line P2, so that the first scribe line P2 passes through the SnO2 layer, the C60 layer, the perovskite film 3 and the nickel oxide layer in sequence;

[0103] (8) forming a Cu layer on the surface of the second transmission layer by thermal evaporation, and then using a laser to scribe a first scribe line P3, so that the first scribe line P3 sequentially passes through the Cu layer, the SnO2 layer, the C60 layer, the perovskite film and the nickel oxide layer;

[0104] (9) Packaging is performed in an air environment to obtain a photovoltaic device.

[0105] The present invention uses a scanning electron microscope to detect the perovskite film obtained in Example 1. Figure 2 As shown, the average grain size of the perovskite film in Example 1 is 800-1000 nm, which is uniform and dense.

[0106] The present invention also performs X-ray diffraction detection on the perovskite film obtained in Example 1. Figure 3 As shown, the perovskite crystal planes inside the perovskite film are well oriented.

[0107] The present invention also performs a current-voltage curve test on the photovoltaic device of Example 1. Figure 4 As shown, the efficiency of the photovoltaic device can reach 20.63%, reflecting excellent photoelectric conversion performance.

[0108] Example 2

[0109] This embodiment provides a photovoltaic device, including a conductive substrate, a hole transport layer, a perovskite film, a first electron transport layer, a second electron transport layer and an electrode layer stacked in sequence. The conductive substrate is a 10×10 cm transparent glass substrate, and an ITO conductive layer is arranged on the surface of the transparent glass substrate; the hole transport layer is nickel oxide with a thickness of 35 nm; the perovskite film is a trans-perovskite absorption layer with a band gap of 1.55 eV and a thickness of 500 nm; the first electron transport layer is C60 with a thickness of 35 nm; the second electron transport layer is SnO2 with a thickness of 8 nm; the electrode layer is Cu with a thickness of 120 nm.

[0110] The method for preparing a photovoltaic device provided in this embodiment specifically comprises the following steps:

[0111] (1) using a laser to scribble a conductive substrate to form a first scribing line P1, so that the first scribing line P1 penetrates the conductive layer of the conductive substrate;

[0112] (2) placing the conductive substrate in step (1) in an isopropanol cleaning solution and ultrasonically cleaning it for 25 minutes. After the ultrasonic cleaning is completed, drying it with nitrogen gas, and then performing an oxygen plasma surface treatment for 80 seconds to complete the cleaning of the conductive substrate;

[0113] (3) depositing a nickel oxide layer on the conductive substrate of step (2) by an atomic deposition method;

[0114] (4) The perovskite precursor FA 0.95 Cs 0.05 PbI 2.5 Br 0.5 , DL-histidine and N,N-dimethylformamide were mixed, and stirred at 700 rpm / min for 360 min at 35° C. to obtain a perovskite solution, wherein the concentration of the perovskite precursor was 0.85 mol / L, and the concentration of DL-histidine was 0.05 mol / L;

[0115] (5) coating the perovskite solution on the surface of the conductive substrate at a coating speed of 20 mm / s by slit coating in an air environment, and simultaneously blowing nitrogen gas at a pressure of 0.6 MPa to volatilize the organic solvent in the precursor solution; after coating, vacuum drying was performed for 70 seconds at room temperature and a vacuum degree of 12 Pa; and then heat treatment was performed at 130° C. for 12 minutes to remove the residual organic solvent and assist the nucleation and growth of perovskite crystals to obtain a perovskite film;

[0116] (6) forming a C60 layer on the surface of the perovskite film by a vacuum deposition method, and then forming a SnO2 layer on the surface of the C60 layer by an atomic deposition method;

[0117] (7) Then, a laser is used to scribe a first scribe line P2, so that the first scribe line P2 passes through the SnO2 layer, the C60 layer, the perovskite film and the nickel oxide layer in sequence;

[0118] (8) forming a Cu layer on the surface of the second transmission layer by thermal evaporation, and then using a laser to scribe a first scribe line P3, so that the first scribe line P3 sequentially passes through the Cu layer, the SnO2 layer, the C60 layer, the perovskite film and the nickel oxide layer;

[0119] (9) Packaging is performed in an air environment to obtain a photovoltaic device.

[0120] Example 3

[0121] This embodiment provides a photovoltaic device, including a conductive substrate, a hole transport layer, a perovskite film, a first electron transport layer, a second electron transport layer and an electrode layer stacked in sequence. The conductive substrate is a 10×10 cm transparent glass substrate, and an ITO conductive layer is arranged on the surface of the transparent glass substrate; the hole transport layer is nickel oxide with a thickness of 40 nm; the perovskite film is a trans-perovskite absorption layer with a band gap of 1.55 eV and a thickness of 700 nm; the first electron transport layer is a C60 layer with a thickness of 25 nm; the second electron transport layer is SnO2 with a thickness of 10 nm; and the electrode layer is Cu with a thickness of 130 nm.

[0122] The method for preparing a photovoltaic device provided in this embodiment specifically comprises the following steps:

[0123] (1) using a laser to scribble a conductive substrate to form a first scribing line P1, so that the first scribing line P1 penetrates the conductive layer of the conductive substrate;

[0124] (2) placing the conductive substrate in step (1) in an isopropanol cleaning solution and ultrasonically cleaning it for 40 minutes. After the ultrasonic cleaning is completed, drying it with nitrogen gas, and then performing an oxygen plasma surface treatment for 45 seconds to complete the cleaning of the conductive substrate;

[0125] (3) depositing a nickel oxide layer on the conductive substrate of step (2) by an atomic deposition method;

[0126] (4) The perovskite precursor FA 0.95 Cs 0.05 PbI 2.5 Br 0.5 , DL-histidine and N,N-dimethylformamide were mixed, and stirred at 45° C. and 820 rpm / min for 400 min to obtain a perovskite solution, wherein the concentration of the perovskite precursor was 1.35 mol / L, and the concentration of DL-histidine was 0.005 mol / L;

[0127] (5) coating the perovskite solution on the surface of the conductive substrate by scraping at a scraping speed of 30 mm / s in an air environment, and simultaneously blowing nitrogen at a pressure of 0.3 MPa to volatilize the organic solvent in the precursor solution; after coating, vacuum drying was performed for 45 seconds at room temperature and a vacuum degree of 6 Pa; and then heat treatment was performed at 110° C. for 18 minutes to remove the residual organic solvent and assist the nucleation and growth of perovskite crystals to obtain a perovskite film;

[0128] (6) forming a C60 layer on the surface of the perovskite film by a vacuum deposition method, and then forming a SnO2 layer on the surface of the C60 layer by an atomic deposition method;

[0129] (7) Then, a laser is used to scribe a first scribe line P2, so that the first scribe line P2 passes through the SnO2 layer, the C60 layer, the perovskite film and the nickel oxide layer in sequence;

[0130] (8) forming a Cu layer on the surface of the second transmission layer by thermal evaporation, and then using a laser to scribe a first scribe line P3, so that the first scribe line P3 sequentially passes through the Cu layer, the SnO2 layer, the C60 layer, the perovskite film and the nickel oxide layer;

[0131] (9) Packaging is performed in an air environment to obtain a photovoltaic device.

[0132] Example 4

[0133] This embodiment provides a photovoltaic device, which is different from Example 1 in that the concentration of DL-histidine in the precursor solution for preparing the perovskite film is 0.2 mol / L, and the rest of the structure, component content, preparation method and process parameters are the same as those in Example 1.

[0134] Example 5

[0135] This embodiment provides a photovoltaic device, which differs from Embodiment 1 in that in step (4) of preparing the perovskite film, the stirring and mixing speed is 650 rpm / min, and the rest of the structure, component content, preparation method and process parameters are the same as those in Embodiment 1.

[0136] Example 6

[0137] This embodiment provides a photovoltaic device, which differs from Embodiment 1 in that in step (4) of preparing the perovskite film, the stirring mixing speed is 900 rpm / min, and the rest of the structure, component content, preparation method and process parameters are the same as those in Embodiment 1.

[0138] Example 7

[0139] This embodiment provides a photovoltaic device, which differs from Embodiment 1 in that in step (5) of preparing the perovskite film, nitrogen is not used for gas blowing treatment, and the rest of the structure, component content, preparation method and process parameters are the same as those of Embodiment 1.

[0140] Example 8

[0141] This embodiment provides a photovoltaic device, which is different from Embodiment 1 in that DL-aspartic acid is used to replace DL-histidine, and the rest of the structure, component content, preparation method and process parameters are the same as those of Embodiment 1.

[0142] Comparative Example 1

[0143] This comparative example provides a photovoltaic device, which is different from Example 1 in that DL-histidine is not added to the perovskite film, and the rest of the structure, component content, preparation method and process parameters are the same as those in Example 1.

[0144] The present invention performs current-voltage tests on the photovoltaic devices in Examples 1 to 8 and Comparative Example 1 to obtain their photoelectric conversion efficiency, and uses a scanning electron microscope to observe the crystal density inside the perovskite film. An atomic force microscope (AFM) is also used to test the number of defect pits in the perovskite film. The results are shown in Table 1.

[0145] Table 1

[0146]

[0147]

[0148] It is not difficult to see from Table 1 that the perovskite films in Examples 1 to 3 and Example 8 are uniform and dense, without defects, and the photovoltaic devices obtained have good electrical properties. In Example 4, the concentration of the added DL-histidine is too high, resulting in the presence of DL-histidine residues during the perovskite crystallization process, which increases the number of defects and makes its uniformity lower than that of Example 1. In Example 5, due to the low stirring speed of the perovskite precursor and the additive, the amino acid additive cannot be evenly dispersed, thereby affecting the uniformity of the crystal; and in Example 6, due to the high stirring speed, the viscosity of the perovskite precursor solution increases, which reduces the spreadability of the liquid film during the coating process and reduces the density between the film-forming crystals. Compared with Example 1, the organic solvent in Example 7 was not completely volatilized when the perovskite film was formed, resulting in an increase in internal defects, resulting in a decrease in the overall performance of the photovoltaic device.

[0149] Compared with Example 1, the photoelectric conversion efficiency of Comparative Example 1 is significantly reduced. This is mainly because no amino acid is added to the perovskite solution used in Comparative Example 1, which causes erosion by moisture in the air during the coating process, causing phase change problems, thereby reducing the photoelectric conversion efficiency.

[0150] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A perovskite solution, characterized in that: The perovskite solution comprises a precursor solution and an amino acid additive, wherein the concentration of the amino acid additive in the perovskite solution is 0.001 to 0.1 mmol / mL; The amino acid additive includes any one of histidine, histidine derivatives, aspartic acid and aspartic acid derivatives, or a combination of at least two of them.

2. The perovskite solution according to claim 1, characterized in that The precursor solution includes a perovskite precursor and an organic solvent; Preferably, the general formula of the perovskite precursor is ABX3; wherein A is a combination of at least two of cesium, methylamino or methylamino; B is lead; X is iodine and / or bromine; Preferably, in the perovskite solution, the concentration of the perovskite precursor is 0.8 to 1.4 mmol / mL; Preferably, the organic solvent includes any one or a combination of at least two of dimethyl sulfoxide, 2-methoxyethanol, N,N-dimethylformamide, N-methylpyrrolidone and acetonitrile.

3. The perovskite solution according to claim 1, characterized in that The amino acid additive includes any one of L-histidine, D-histidine, DL-histidine, L-aspartic acid, D-aspartic acid, DL-aspartic acid, histidine derivatives and aspartic acid derivatives, or a combination of at least two thereof.

4. A method for preparing a perovskite solution according to any one of claims 1 to 3, characterized in that: The preparation method comprises: stirring and mixing a precursor solution and an amino acid additive.

5. The method for preparing a perovskite solution according to claim 4, characterized in that: The stirring and mixing temperature is 35 to 50°C; Preferably, the stirring and mixing speed is 650-850 rpm / min; Preferably, the stirring and mixing time is 300 to 480 minutes.

6. A method for preparing a perovskite film, characterized in that: The preparation method comprises: The perovskite solution according to any one of claims 1 to 3 is coated on the surface of the substrate during the air blowing treatment, and then heat treated to obtain the perovskite film.

7. The method for preparing a perovskite thin film according to claim 6, characterized in that: The coating includes blade coating and / or slit coating; Preferably, the coating speed is 20 to 30 mm / s; Preferably, the air blowing treatment uses nitrogen; Preferably, the pressure of the air blowing treatment is 0.2-0.6 MPa; Preferably, the temperature of the heat treatment is 100-150°C; Preferably, the heat treatment time is 10 to 20 minutes.

8. The method for preparing a perovskite thin film according to claim 6 or 7, characterized in that: The preparation method further comprises: after the coating is completed and before the heat treatment, performing a vacuum drying treatment; Preferably, the vacuum degree of the vacuum drying process is 8 to 12 Pa; Preferably, the temperature of the vacuum drying treatment is room temperature; Preferably, the vacuum drying treatment lasts for 45 to 70 seconds.

9. A perovskite film, characterized in that: The perovskite film is prepared by the method for preparing a perovskite film according to any one of claims 6 to 8; The average grain size of the perovskite film is 800-1000nm.

10. A photovoltaic device, characterized in that: The photovoltaic device comprises a conductive substrate, a first transmission layer, a perovskite film, a second transmission layer and an electrode layer stacked in sequence. The perovskite film is prepared by the preparation method of the perovskite film described in any one of claims 6 to 8, or by the perovskite film described in claim 9.

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