Preparation method for lead iodide solution, perovskite solar cell, photovoltaic module, photovoltaic system, electric device and power generation device

Abstract

The present application relates to a preparation method for a lead iodide solution, a perovskite solar cell, a photovoltaic module, a photovoltaic system, an electric device and a power generation device. The preparation method for the lead iodide solution comprises the following step: mixing and reacting elemental lead with elemental iodine in a solvent system comprising a polar solvent to form a lead iodide solution, wherein the number of donors of the polar solvent is greater than or equal to 20. The preparation method of the present application is simple in terms of process, low in terms of cost and high in terms of the purity of a lead iodide product, and when the lead iodide product is used in the preparation of a perovskite thin film for a perovskite solar cell, the photoelectric conversion efficiency of the perovskite solar cell can be improved.

Description

Preparation method of lead iodide solution, perovskite battery, photovoltaic module, photovoltaic system, power consumption device and power generation device

[0001] Cross-references

[0002] This application claims priority to Chinese Patent Application No. 2024103821757, filed on March 29, 2024, entitled “Method for preparing lead iodide solution, perovskite cell, photovoltaic module, photovoltaic system, electrical device and power generation device,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application relates to the field of solar cells, and specifically to a method for preparing a lead iodide solution, a perovskite cell, a photovoltaic module, a photovoltaic system, an electrical device, and a power generation device. Background Art

[0004] With the rapid development of new energy, solar cells have been widely used in military, aerospace, industrial, commercial, agricultural, and communications fields. Perovskite solar cells, devices that convert solar energy into electricity using the photoelectric conversion mechanism of perovskite crystal materials, are currently the third generation of solar cells. They have many advantages, such as high photoelectric conversion efficiency, simple manufacturing process, and low production cost, and have been widely studied in recent years.

[0005] Lead iodide (PI) is a key raw material for perovskite cells, commonly used to prepare the perovskite light-absorbing layer. The purity of the PBI reagent significantly impacts the photoelectric conversion efficiency and stability of perovskite cells. Perovskite cells prepared using low-purity PBI generally exhibit lower photoelectric conversion efficiency and stability. However, high-purity PBI is expensive, significantly increasing the production cost of perovskite cells.

[0006] Therefore, developing a method for preparing lead iodide with low production cost and high product purity has become one of the important research directions in this field. Summary of the Invention

[0007] The present application is made in view of the above-mentioned problems, and one of its purposes is to provide a method for preparing a lead iodide solution, which has a simple process, low cost and high product purity.

[0008] To achieve the above-mentioned object, the first aspect of the present application provides a method for preparing a lead iodide solution, comprising the following steps: mixing a lead element and an iodine element in a solvent system including a polar solvent to form a lead iodide solution, wherein the donor number of the polar solvent is greater than or equal to 20.

[0009] The preparation method of the lead iodide solution described in the present application uses elemental lead and elemental iodine as raw materials, and forms a lead iodide solution by a one-step reaction in a solvent system including a polar solvent having a donor number greater than or equal to 20; in the above-mentioned solvent system, elemental iodine is affected by the polarization effect of the polar solvent and is polarized into iodine anions, which then react with lead to form lead iodide. The lead iodide solution can be directly added to a precursor powder and / or solution containing halide cations to prepare a perovskite precursor solution. The preparation method has a simple process, low production cost, and can obtain a high-purity lead iodide product. In addition, the preparation method prepares lead iodide with a solvent ligand, which can react with I during the perovskite film formation process. - Ion competition center Pb 2+ ions, avoid I - ions and Pb 2+ The rapid formation of PbI octahedrons between ions can delay crystallization, which is beneficial to perovskite film formation, improves film quality, and thus improves the photoelectric conversion efficiency and stability of perovskite cells.

[0010] In any embodiment, the donor number of the polar solvent is 20-61. In this way, the iodine element can be effectively polarized to promote the smooth reaction of lead element and iodine element to form lead iodide, and the polar solvent can be prevented from having too strong a coordination ability and exceeding 1 - The coordination ability of the ions is reduced, which inhibits the formation of perovskite PbI octahedron and affects the formation of the perovskite phase in the perovskite film.

[0011] In any embodiment, the number of donors in the polar solvent is 24 to 40. In this way, it is possible to further avoid the influence of the coordination ability of the polar solvent on the formation of the perovskite phase during the preparation of the perovskite film.

[0012] In any embodiment, the polar solvent includes a first polar solvent and a second polar solvent. The first polar solvent has a donor number DN1, where 20 ≤ DN1 < 24; and the second polar solvent has a donor number DN2, where DN2 > DN1. Thus, if the first polar solvent has a donor number DN1 < 24, using a second polar solvent with a relatively larger donor number DN2 can accelerate the reaction and shorten the reaction time.

[0013] In any embodiment, 27 ≤ DN2 < 34; the volume fraction of the first polar solvent in the solvent system is x, the volume fraction of the second polar solvent is y, and 0.1 ≤ y / x ≤ 0.4. Thus, when the first polar solvent has a donor number of 20 ≤ DN1 < 24 and is used in conjunction with a second polar solvent having a donor number of 27 ≤ DN2 < 34, mixing the two in a ratio of 0.1 ≤ y / x ≤ 0.4 can promote reaction progress and shorten reaction time.

[0014] In any embodiment, 34 ≤ DN2 < 50; the volume fraction of the first polar solvent in the solvent system is x, the volume fraction of the second polar solvent is y, and 0.015 ≤ y / x ≤ 0.08. Thus, when the first polar solvent has a donor number of 20 ≤ DN1 < 24 and is used in conjunction with a second polar solvent having a donor number of 34 ≤ DN2 < 50, mixing the two in a ratio of 0.015 ≤ y / x ≤ 0.08 can promote reaction progress and shorten reaction time.

[0015] In any embodiment, 50 ≤ DN2 < 61; the volume fraction of the first polar solvent in the solvent system is x, the volume fraction of the second polar solvent is y, and 0.01 ≤ y / x ≤ 0.045. When the donor number of the first polar solvent is 20 ≤ DN1 < 24 and a second polar solvent with a donor number of 50 ≤ DN2 < 61 is used in combination, the two polar solvents can be mixed in a ratio of 0.01 ≤ y / x ≤ 0.045 to promote the reaction and shorten the reaction time.

[0016] In any embodiment, the solvent system includes the polar solvent and a second solvent, wherein the donor number of the second solvent is less than 20; and the volume content of the second solvent in the solvent system is no greater than the volume content of the polar solvent. Thus, the presence of the polar solvent in a content no less than that of the second solvent in the solvent system ensures that elemental iodine is polarized to iodide ions by the polarization effect of the polar solvent. The iodide ions then react with lead to form lead iodide.

[0017] In any embodiment, the second solvent comprises one or more of acetonitrile, 2-methylpropionitrile, N,N-dimethyltrifluoroacetamide, benzaldehyde, and acetone. Mixing the second solvent with the polar solvent enables the reaction of elemental lead with elemental iodine to produce a high-purity lead iodide product.

[0018] In any embodiment, the polar solvent includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, tetramethylurea, 1,3-dimethyl-2-imidazolidinone, 1,3-dimethylpropyleneurea, ethylenediamine, and hexamethylphosphoric triamide. Using the above polar solvent, lead and iodine can react to produce a high-purity lead iodide product.

[0019] In any embodiment, the molar ratio of the lead element to the iodine element is greater than or equal to 1:1. In this way, the iodine element can be fully reacted, the residual iodine element in the solution to form impurities can be reduced, and a high-purity lead iodide solution can be obtained.

[0020] In any embodiment, the molar ratio of the lead element to the iodine element is 1-1.5: 1. In this way, the excess lead element can better enable the iodine element to react fully and completely.

[0021] In any embodiment, after the mixing reaction is completed, the preparation method further comprises the step of filtering the resulting reaction solution to obtain a filtrate. When the lead element is in excess, the remaining lead element can be removed by filtration to improve the purity of the product.

[0022] In any embodiment, the mixing reaction time is not less than 6 hours. Generally, compared with the traditional chemical vapor transport method, the preparation method of the present application has a shorter process time.

[0023] In any embodiment, the mixing reaction time is 6 hours to 10 hours. Compared with the traditional chemical vapor transport method, the preparation method of the lead iodide solution of the present application has a shorter process time.

[0024] In any embodiment, the temperature of the mixing reaction is 0° C.-60° C. The lead iodide solution of the present application can be carried out at a mild reaction temperature, which is more convenient.

[0025] In any embodiment, the mass volume ratio of the iodine element to the solvent system is 0.04 mg / μL-0.56 mg / μL, which is conducive to the full progress of the reaction and enables the generated lead iodide to be well dissolved in the solvent.

[0026] In any embodiment, after the mixing reaction is completed, the preparation method further comprises the step of mixing the resulting reaction solution with a Lewis base ligand, wherein the number of donors of the Lewis base ligand is greater than the number of donors of the polar solvent. In this way, a complex of lead iodide and the Lewis base ligand can be formed. When the complex is used to prepare a perovskite film, the complex can better avoid I - ions and Pb 2+ The rapid formation of PbI octahedrons between ions can delay crystallization and improve the quality of perovskite film formation.

[0027] In any embodiment, the Lewis base ligand has a donor number of 20.1-61.1.

[0028] In any embodiment, the donor number of the Lewis base ligand is 26-40.

[0029] In any embodiment, the Lewis base ligand includes one or more of urea, N-methylurea, 1,1-dimethylurea, trimethylurea, 1,1,3,3-tetramethylurea, 1,3-dimethyl-2-imidazolidinone, 6-amino-3-methyluracil, 1,3-dimethylbarbituric acid, thiourea, N-methylthiourea, 1,1-dimethylthiourea, trimethylthiourea, 1,1,3,3-tetramethylthiourea, N-methylpyrrolidone and dimethyl sulfoxide.

[0030] In any embodiment, the mass volume ratio of the Lewis base ligand to the reaction solution is 0.9 mg / mL to 600 mg / mL. In this way, the Lewis base ligand can fully replace the polar solvent ligand, and the lead iodide having the polar solvent ligand can be fully converted into the lead iodide having the Lewis base ligand.

[0031] The second aspect of the present application provides a lead iodide solution, which is prepared by the preparation method of the lead iodide solution of the first aspect of the present application. The lead iodide solution of the present application can be directly added to a precursor powder and / or solution containing halide cations to prepare a perovskite precursor solution. The lead iodide solution includes lead iodide with a solvent ligand, and during the perovskite film formation process, the ligand can react with I - Ion competition center Pb 2+ ions, avoid I - ions and Pb 2+ The rapid formation of PbI octahedrons between ions can delay crystallization, which is beneficial to perovskite film formation, improves film quality, and thus improves the photoelectric conversion efficiency and stability of perovskite cells.

[0032] The third aspect of the present application provides a method for preparing a lead iodide adduct, comprising filtering the lead iodide solution prepared by the method for preparing the lead iodide solution of the first aspect of the present application, collecting the filtrate, drying and crystallizing the solution to obtain the lead iodide adduct. The lead iodide adduct prepared by this method contains a solvent ligand and can be used to prepare a perovskite precursor solution, thereby improving the film quality of the perovskite and the photoelectric conversion efficiency and stability of the perovskite cell.

[0033] A fourth aspect of the present application provides a lead iodide adduct prepared by the method for preparing the lead iodide adduct of the third aspect of the present application. This lead iodide adduct can be used as a high-purity lead iodide source for preparing perovskite thin films, thereby improving the film quality of perovskite and enhancing the photoelectric conversion efficiency and stability of perovskite cells.

[0034] A fifth aspect of the present application provides a perovskite cell comprising a perovskite layer, wherein the raw materials for preparing the perovskite layer include one or more of a lead iodide solution prepared by the method for preparing a lead iodide solution according to the first aspect of the present application or a lead iodide adduct prepared by the method for preparing a lead iodide adduct according to the third aspect of the present application. The perovskite cell has high photoelectric conversion efficiency and stability.

[0035] A sixth aspect of the present application provides a method for preparing a perovskite battery, wherein the perovskite battery includes a perovskite layer, and the method comprises the following steps:

[0036] A lead iodide solution is prepared according to the method for preparing a lead iodide solution of the first aspect of the present application, and the prepared lead iodide solution is used as a raw material for a perovskite precursor solution, or the lead iodide adduct prepared by the method for preparing a lead iodide adduct of the third aspect of the present application is used as a raw material to prepare a perovskite layer.

[0037] The seventh aspect of the present application provides a photovoltaic component, comprising the perovskite cell of the fifth aspect of the present application.

[0038] An eighth aspect of the present application provides a photovoltaic system, comprising the photovoltaic assembly of the seventh aspect of the present application.

[0039] The ninth aspect of the present application provides an electrical device, comprising the photovoltaic system of the eighth aspect of the present application.

[0040] The tenth aspect of the present application provides a power generation device, including the photovoltaic system of the eighth aspect of the present application.

[0041] The details of one or more embodiments of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to better describe and illustrate the embodiments or examples of the applications disclosed herein, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the accompanying drawings should not be considered to limit the scope of the disclosed applications, the embodiments or examples currently described, and any of the best modes currently understood for these applications. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0043] FIG1 is a schematic structural diagram of an electric device according to an embodiment of the present application. DETAILED DESCRIPTION

[0044] Below, some embodiments of the lead iodide preparation method, perovskite battery, and electrical device of the present application are described in detail with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of actually identical structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0045] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is merely an abbreviation for a combination of these values. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when a parameter is expressed as an integer selected from "2-10", this is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0046] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0047] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0048] In this application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0049] In this application, "a plurality of" or "a plurality of" refers to a number greater than or equal to 2 unless otherwise specified. For example, "one or more" means one or more than or equal to two.

[0050] As used herein, "combination thereof", "any combination thereof", "any combination thereof" and the like include all suitable combinations of any two or more of the listed items.

[0051] Herein, the “suitable” mentioned in “suitable combination”, “suitable method”, “any suitable method”, etc. shall be based on the technical solution that can implement the present application.

[0052] Herein, the terms "preferred," "better," "more preferred," and "suitable" are used solely to describe preferred implementations or examples and should not be construed as limiting the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, each "preferred" term is considered independent unless otherwise specified and there are no contradictions or mutual constraints.

[0053] In this application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be understood as limiting the scope of protection of this application.

[0054] In this application, the terms "first," "second," "third," "fourth," etc. in "the first aspect," "the second aspect," "the third aspect," "the fourth aspect," etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or quantity, nor should they be understood as implicitly indicating the importance or quantity of the indicated technical features. Furthermore, "first," "second," "third," "fourth," etc. serve only as non-exhaustive enumeration and description, and should be understood not to constitute a closed-ended limitation on quantity.

[0055] In this application, the term "room temperature" generally refers to 4°C-35°C, and may refer to 20°C±5°C. In some embodiments of this application, room temperature refers to 20°C-30°C.

[0056] In this application, when referring to a data range, if the unit is only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 3h-5h or 3h-5h both mean that the units of the left endpoint "3" and the right endpoint "5" are both hours.

[0057] The weights of the relevant components mentioned in the embodiment description of this application not only refer to the content of each component, but also represent the proportional relationship of the weights between the components. Therefore, as long as the content of the relevant components in the embodiment description of this application is proportionally enlarged or reduced according to the proportion, it is within the scope disclosed in the embodiment description of this application.

[0058] The purity of the lead iodide reagent has a significant impact on the photoelectric conversion efficiency and stability of the perovskite battery. When a low-purity lead iodide reagent is used to prepare a perovskite battery, the photoelectric conversion efficiency and stability of the battery are generally low. The use of a high-purity lead iodide reagent can improve the photoelectric conversion efficiency and stability of the battery; however, the current high-purity lead iodide reagent is expensive, resulting in a significant increase in the production cost of the perovskite battery. In response to this, the present application improves the preparation method of lead iodide and provides a method for preparing a lead iodide solution with a simple process, low production cost, and high product purity.

[0059] A first aspect of the present application provides a method for preparing a lead iodide solution, comprising the following steps: mixing a lead element and an iodine element in a solvent system including a polar solvent to form a lead iodide solution; wherein the donor number (DN) of the polar solvent is greater than or equal to 20.

[0060] Traditional methods for preparing lead iodide mainly include solution method and chemical vapor transport method. Among them, the solution method is to react lead salts such as lead nitrate and lead acetate with potassium iodide or hydroiodic acid to prepare lead iodide. This method has strict requirements on the pH value of the solution system when preparing lead iodide, and the prepared lead iodide crystals are in the form of fine powder with varying purity, making the product purity difficult to control. Although the chemical vapor transport method can produce lead iodide products with higher purity, it has high requirements on the vacuum degree of the equipment, consumes a lot of energy, and is very time-consuming. The process generally takes more than 3 days.

[0061] The method for preparing the lead iodide solution described above uses elemental lead and elemental iodine as raw materials, and forms the lead iodide solution through a one-step reaction in a solvent system including a polar solvent having a donor number greater than or equal to 20. In this solvent system, elemental iodine is polarized to iodine anions by the polarization effect of the polar solvent, which then reacts with lead to form lead iodide. This lead iodide solution can be directly added to a precursor powder / solution containing halide cations to prepare a perovskite precursor solution.

[0062] In addition, the preparation method produces lead iodide with a solvent ligand, which can react with I during the perovskite film formation process. - Ion competition center Pb 2+ ions, and Pb 2+ ions to coordinate and avoid I -ions and Pb 2+ The rapid formation of PbI octahedra between ions can delay crystallization, which is beneficial to improving the quality of perovskite film formation, and thus the photoelectric conversion efficiency and stability of perovskite cells. Lead iodide with ligands can be used as a high-purity lead source for preparing perovskite cells.

[0063] The raw materials used in this preparation method are elemental lead and elemental iodine. The purity of these raw materials is easier to control than that of lead salts and iodine salts. The purity of the lead iodide product is less affected by fluctuations in the purity of the raw materials, and the product purity is higher. In addition, the preparation method is simple, and its production cost is lower than that of commercially available high-purity lead iodide. The lead iodide solution prepared by the preparation method of the present application can be directly used in the production of perovskite batteries. The process is simple, and there is no need to control the pH value of the solution system, which can make the prepared perovskite battery have better process stability.

[0064] It should be noted that the donor number DN of a polar solvent is an indicator of the ability of a polar solvent compound to donate electrons, and is a measure of the ability of a solvent to dissolve cations and Lewis acids. The donor number DN value is defined as: in a dilute solution of the non-coordinating solvent 1,2-dichloroethane with a DN of zero, the negative enthalpy of the formation of a 1:1 adduct between a Lewis base and the standard Lewis acid antimony pentachloride (SbCl5) is expressed in kcal / mol. The DN value of the corresponding Lewis base is calculated by measuring the enthalpy change ΔH of the 1:1 adduct. The test method can be: by adding sodium chlorate (the concentration of sodium chlorate is 0.2M) in the corresponding solvent 23 Na NMR can be used to infer the DN value of the corresponding solvent (J.Am.Chem.Soc.1971,93,22,5620-5623, each test spectrum is tested three times and the average is calculated). Generally speaking, the larger the DN of the solvent compound, the stronger the electron donating ability of the solvent molecule, that is, the stronger the coordination ability.

[0065] In addition, it is understood that the solvent system may entirely comprise the aforementioned polar solvents having a donor number greater than or equal to 20, or may, in addition to the aforementioned polar solvents having a donor number greater than or equal to 20, also include solvents having a donor number less than 20. That is, the solvent system may be a mixed solvent of the aforementioned polar solvents having a donor number greater than or equal to 20 and solvents having a donor number less than 20. Furthermore, the aforementioned polar solvents having a donor number greater than or equal to 20 may include multiple polar solvents of different types having different donor numbers.

[0066] In some embodiments, the volume content of the solvent having a donor number of less than 20 is no greater than that of the polar solvent. Thus, in the aforementioned solvent system, the presence of a polar solvent having a content no less than that of the solvent having a donor number of less than 20 ensures that elemental iodine is polarized to iodide ions by the polarization effect of the polar solvent. The iodide ions then react with lead to form lead iodide.

[0067] In some embodiments, the solvent having a donor number less than 20 includes one or more of acetonitrile, 2-methylpropionitrile, N,N-dimethyltrifluoroacetamide, benzaldehyde, and acetone.

[0068] It is worth noting that although a polar solvent with a large DN value can be used to prepare a high-purity lead iodide solution, and it is helpful for the film formation of perovskite; however, when the DN value of the polar solvent is particularly large and the amount of the polar solvent is relatively large, the formation of perovskite will be hindered. Therefore, when the DN value of the polar solvent used is particularly large, the amount of the polar solvent can be appropriately reduced, and it can be used in conjunction with a solvent with a smaller DN value. It is understandable that what is considered here is the subsequent application of the prepared lead iodide solution. When the DN value of the polar solvent is particularly large, lead iodide can still be synthesized.

[0069] In some embodiments, the polar solvent used in the preparation method of the present application has a donor number of 20-61. Selecting a polar solvent with a donor number within the above range can not only effectively polarize the iodine element, promote the smooth reaction of the lead element and the iodine element to form lead iodide, but also avoid the polar solvent from having too strong a coordination ability, which may cause the reaction to exceed 1. - The coordination ability of the ions is greatly improved, and the formation of the PbI octahedron in the perovskite is inhibited during the subsequent preparation of the perovskite, which affects the formation of the perovskite phase in the perovskite film.

[0070] It will be appreciated that the donor number of the polar solvent may be, but is not limited to, 20, 22, 24, 25, 26, 28, 30, 32, 34, 35, 36, 38, 40, 42, 44, 45, 46, 48, 50, 52, 54, 55, 56, 58, 60, 61, and any number within the range formed by any two of the above numbers.

[0071] In some embodiments, the polar solvent used has a donor number of 24 to 40. Selecting a polar solvent with a donor number within the above range not only effectively promotes the reaction but also further avoids the inhibition of the formation of perovskite PbI octahedra due to the excessive coordination ability of the polar solvent, thereby further avoiding the influence of the polar solvent ligand on the formation of the perovskite phase.

[0072] In some embodiments, the polar solvent includes a first polar solvent and a second polar solvent. The first polar solvent has a donor number DN1, where 20 ≤ DN1 < 24; the second polar solvent has a donor number DN2, where DN2 > DN1. That is, the polar solvent includes two solvents with different donor numbers. If the first polar solvent in the solvent system has a relatively low donor number DN1, combining it with a second polar solvent with a relatively high donor number DN2 can further promote the reaction and shorten the reaction time.

[0073] In some embodiments, 20 ≤ DN1 < 24, 27 ≤ DN2 < 34; the volume fraction of the first polar solvent in the solvent system is x, the volume fraction of the second polar solvent is y, and 0.1 ≤ y / x ≤ 0.4. When the donor number of the first polar solvent in the solvent system is 20 ≤ DN1 < 24, and a second polar solvent with a donor number of 27 ≤ DN2 < 34 is used in combination, the first polar solvent and the second polar solvent are mixed in a ratio of 0.1 ≤ y / x ≤ 0.4, which can promote the reaction and shorten the reaction time.

[0074] In some embodiments, 20 ≤ DN1 < 24, 34 ≤ DN2 < 50; the volume fraction of the first polar solvent in the solvent system is x, the volume fraction of the second polar solvent is y, and 0.015 ≤ y / x ≤ 0.08. When the donor number of the first polar solvent in the solvent system is 20 ≤ DN1 < 24, and a second polar solvent with a donor number of 34 ≤ DN2 < 50 is used in combination, the first polar solvent and the second polar solvent are mixed in a ratio of 0.015 ≤ y / x ≤ 0.08, which can promote the reaction and shorten the reaction time.

[0075] In some embodiments, 20 ≤ DN1 < 24, 50 ≤ DN2 < 61; the volume fraction of the first polar solvent in the solvent system is x, the volume fraction of the second polar solvent is y, and 0.01 ≤ y / x ≤ 0.045. When the donor number of the first polar solvent in the solvent system is 20 ≤ DN1 < 24, and a second polar solvent with a donor number of 50 ≤ DN2 < 61 is used in combination, the first polar solvent and the second polar solvent are mixed in a ratio of 0.01 ≤ y / x ≤ 0.045, which can promote the reaction and shorten the reaction time.

[0076] It can be understood that when the DN2 of the second polar solvent used in combination with the first polar solvent with 20≤DN1<24 is large, the amount of the second polar solvent can be appropriately reduced; when the DN2 of the second polar solvent used in combination with the first polar solvent with 20≤DN1<24 is small, the amount of the second polar solvent can be appropriately increased.

[0077] In some embodiments, the polar solvent used includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, tetramethylurea, 1,3-dimethyl-2-imidazolidinone, 1,3-dimethylpropyleneurea, ethylenediamine and hexamethylphosphoric triamide.

[0078] In some embodiments, the molar ratio of lead and iodine used in the preparation method of the present application is greater than or equal to 1:1. Controlling the molar ratio of lead and iodine to a dosage ratio greater than or equal to 1:1 allows the iodine to fully react, and after the reaction is complete, excess lead can be removed by filtration. In this way, the iodine and lead residues in the solution can be reduced to form impurities, thereby obtaining a high-purity lead iodide solution.

[0079] It is understood that when the molar ratio of lead and iodine is 1:1, filtration is not required after the reaction is completed, and the formed lead iodide solution can be directly used for the preparation of the perovskite film of the perovskite battery. When the molar ratio of lead and iodine is greater than 1:1, the reaction solution needs to be filtered after the reaction is completed to remove excess lead in the reaction solution. Theoretically, the molar ratio of lead and iodine can be very large, and it is only necessary to filter and remove the remaining lead solid after the reaction is completed.

[0080] In some embodiments, the molar ratio of lead to iodine is 1-1.5:1. This not only allows the iodine to react fully and completely, but also reduces the amount of lead used, thereby reducing costs. It is understood that the molar ratio of lead to iodine can be, but is not limited to, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, and any ratio within the range formed by any two of the above ratios.

[0081] In some embodiments, the mass volume ratio of elemental iodine to the solvent system is 0.04 mg / μL-0.56 mg / μL. Controlling the mass volume ratio of elemental iodine to the solvent system within the above range can facilitate the full progress of the reaction and enable the generated lead iodide to be well dissolved in the polar solvent.

[0082] It will be appreciated that the mass volume ratio of elemental iodine to the solvent system may be, but is not limited to, 0.04 mg / μL, 0.06 mg / μL, 0.08 mg / μL, 0.1 mg / μL, 0.12 mg / μL, 0.15 mg / μL, 0.18 mg / μL, 0.2 mg / μL, 0.22 mg / μL, 0.25 mg / μL, 0.28 mg / μL, 0.3 mg / μL, 0.32 mg / μL, 0.35 mg / μL, 0.38 mg / μL, 0.4 mg / μL, 0.42 mg / μL, 0.45 mg / μL, 0.48 mg / μL, 0.5 mg / μL, 0.52 mg / μL, 0.55 mg / μL, 0.56 mg / μL, and any value within the range formed by any two of the above values.

[0083] In some embodiments, the time of mixing reaction is not less than 6h. The mixing reaction time of the preparation method of the present application is generally more than 6h, and compared to traditional chemical vapor transport method, the preparation method process of the present application is shorter. Specifically, the end point of the reaction can be judged by observing the color change of the reaction solution. When the color of the reaction solution changes from dark brown to transparent yellow, the reaction can be regarded as reaching the end point. The purity of the prepared lead iodide solution can be directly obtained by elemental analysis method, or by performing XRD test after extracting the solute in the solution. Those skilled in the art can appropriately adjust the reaction time according to the reaction end point to ensure that the iodine element reacts completely.

[0084] In some embodiments, the mixing reaction time is 6 h-10 h, and the mixing reaction temperature is 0° C.-60° C. Usually, the reaction time can be controlled within 6 h-10 h, and the reaction conditions are relatively mild.

[0085] It is understood that the time of the mixed reaction can be, but is not limited to, 6h, 6.2h, 6.5h, 6.8h, 7h, 7.2h, 7.5h, 7.8h, 8h, 8.2h, 8.5h, 8.8h, 9h, 9.2h, 9.5h, 9.8h, 10h, and any numerical value within the range formed by any two of the above values. The temperature of the mixed reaction can be, but is not limited to, 0°C, 2°C, 5°C, 8°C, 10°C, 12°C, 15°C, 18°C, 20°C, 22°C, 25°C, 28°C, 30°C, 32°C, 35°C, 38°C, 40°C, 42°C, 45°C, 48°C, 50°C, 52°C, 55°C, 58°C, 60°C, and any numerical value within the range formed by any two of the above values.

[0086] In some embodiments, after the reaction of the lead element and the iodine element is completed, the reaction solution is mixed with a Lewis base ligand (L) to form a lead iodide adduct (PbI2-L) having the above-mentioned Lewis base ligand (L). The donor number DN of the Lewis base ligand is greater than the donor number DN of the polar solvent. By adding a Lewis base ligand (L) having a donor number DN greater than that of the polar solvent to the reaction solution to form the lead iodide adduct PbI2-L, the Lewis base ligand in PbI2-L can better compete with the I- ion for the central Pb during the perovskite film formation process than the polar solvent ligand. 2+ ions, better avoid I - ions and Pb 2+ The rapid formation of PbI octahedrons between ions can delay crystallization and improve the quality of perovskite film formation.

[0087] It is understood that a molecule or atom group that can donate an electron cloud is called a Lewis base. A Lewis base can react with a Lewis acid to form a complex, in which case the Lewis base acts as a ligand.

[0088] Specifically, a Lewis base ligand having a donor number DN greater than that of the polar solvent can be added to a lead iodide solution prepared using a polar solvent, the temperature is raised and stirred to dissolve, and the solution is cooled and crystallized. The solvent can then be removed by methods such as reduced pressure distillation, dropwise addition of an antisolvent, and heating evaporation to obtain a solute, namely, a lead iodide adduct PbI2-L.

[0089] In some embodiments, the donor number DN of the Lewis base ligand is 20.1-61.1. Further, the donor number DN of the Lewis base ligand is 26-40. It is understood that the donor number DN of the Lewis base ligand can be, but is not limited to, 20.1, 22, 24, 25, 26, 28, 30, 32, 34, 35, 36, 38, 40, 42, 44, 45, 46, 48, 50, 52, 54, 55, 56, 58, 60, 61, 61.1, and any value within the range formed by any two of the above values.

[0090] The Lewis base ligand can be any solid or liquid compound having a donor number DN greater than that of the polar solvent used. In some embodiments, the Lewis base ligand can include one or more of urea, N-methylurea, 1,1-dimethylurea, trimethylurea, 1,1,3,3-tetramethylurea, 1,3-dimethyl-2-imidazolidinone, 6-amino-3-methyluracil, 1,3-dimethylbarbituric acid, thiourea, N-methylthiourea, 1,1-dimethylthiourea, trimethylthiourea, 1,1,3,3-tetramethylthiourea, N-methylpyrrolidone, and dimethyl sulfoxide.

[0091] In some embodiments, the mass-to-volume ratio of the Lewis base ligand to the reaction solution is 0.9 mg / mL to 600 mg / mL. Controlling the mass-to-volume ratio of the Lewis base ligand to the reaction solution within this range allows the Lewis base ligand to fully replace the polar solvent ligand, thereby fully converting the lead iodide having the polar solvent ligand into the lead iodide having the Lewis base ligand.

[0092] It will be appreciated that the mass volume ratio of the Lewis base ligand to the reaction solution may be, but is not limited to, 0.9 mg / mL, 1 mg / mL, 2 mg / mL, 5 mg / mL, 10 mg / mL, 20 mg / mL, 50 mg / mL, 100 mg / mL, 120 mg / mL, 150 mg / mL, 180 mg / mL, 200 mg / mL, 220 mg / mL, 250 mg / mL, 280 mg / mL, 300 mg / mL, 320 mg / mL, 350 mg / mL, 380 mg / mL, 400 mg / mL, 420 mg / mL, 450 mg / mL, 480 mg / mL, 500 mg / mL, 520 mg / mL, 550 mg / mL, 580 mg / mL, 600 mg / mL, and any value within the range formed by any two of the above values.

[0093] The second aspect of the present application provides a lead iodide solution, which is prepared by the preparation method of the lead iodide solution of the first aspect of the present application. The lead iodide solution of the present application can be used as a high-purity lead source and directly added to a precursor powder and / or solution containing halide cations to prepare a perovskite precursor solution. The lead iodide solution includes lead iodide with a solvent ligand, which can react with I during the perovskite film formation process. - Ion competition center Pb 2+ ions, avoid I - ions and Pb 2+ The rapid formation of PbI octahedrons between ions can delay crystallization, which is beneficial to perovskite film formation, improves film quality, and thus improves the photoelectric conversion efficiency and stability of perovskite cells.

[0094] The third aspect of the present application provides a method for preparing a lead iodide adduct. The lead iodide solution prepared by the method for preparing the lead iodide solution of the first aspect of the present application is filtered, the filtrate is collected, and the filtrate is dried and crystallized to obtain a lead iodide adduct. The lead iodide adduct prepared by this method contains a solvent ligand and is used to prepare a perovskite precursor solution, thereby improving the film quality of the perovskite and the photoelectric conversion efficiency and stability of the perovskite cell.

[0095] A fourth aspect of the present application provides a lead iodide adduct, which is prepared by the method for preparing the lead iodide adduct of the third aspect of the present application. This lead iodide adduct can be used as a high-purity lead source for preparing perovskite thin films, thereby improving the film quality of perovskite and enhancing the photoelectric conversion efficiency and stability of perovskite cells.

[0096] The fifth aspect of the present application provides a perovskite cell, comprising a perovskite layer, wherein the raw materials for preparing the perovskite layer include one or more of the lead iodide solution prepared by the preparation method of the first aspect of the present application or the lead iodide adduct prepared by the preparation method of the lead iodide adduct of the third aspect of the present application. Specifically, in some embodiments, the lead iodide solution or lead iodide adduct prepared in the present application can be mixed with a certain amount of formamidine hydroiodide and cesium iodide, and stirred to obtain a perovskite precursor solution; then, the above-mentioned perovskite precursor solution is dropwise added to a substrate containing a hole transport layer, and the perovskite film is obtained by spin coating and annealing.

[0097] It is understandable that different raw materials can be selected according to the changes in the perovskite material and the lead iodide solution or lead iodide adduct prepared in this application to prepare the perovskite precursor solution, such as using a raw material containing a tin source to prepare a tin-lead-based perovskite material; for example, using a raw material containing anions such as a chlorine source or a bromine source to prepare a perovskite material containing mixed anions; for example, using a raw material containing other monovalent cations (such as methylamine cations) to prepare a perovskite material containing mixed monovalent cations. This is not limited here.

[0098] In some embodiments, the perovskite cell may further include other film layer structures, such as a first electrode layer and a second electrode layer, wherein the perovskite layer is located between the first electrode layer and the second electrode layer. The first electrode layer is used to collect one of the electrons or holes generated by the light absorbing layer, and the second electrode layer is used to collect the other of the electrons or holes generated by the light absorbing layer.

[0099] In some embodiments, at least one of the first electrode layer and the second electrode layer is a transparent electrode for light incidence. In one example, the perovskite cell further includes a substrate structure for supporting the membrane layer of the perovskite cell. The first electrode layer is disposed on the substrate structure; further, both the first electrode layer and the substrate structure are made of transparent materials. It is understood that in other examples, the second electrode layer may be disposed on the substrate structure, and both the second electrode layer and the substrate structure may be made of transparent materials.

[0100] In some embodiments, the transparent electrode may be a transparent conductive metal oxide electrode. Without limitation, the transparent conductive metal oxide is but not limited to one or more of the following materials: FTO (fluorine-doped tin oxide), ITO (tin-doped indium oxide), AZO (aluminum-doped zinc oxide), BZO (boron-doped zinc oxide), IZO (indium zinc oxide), IWO (tungsten-doped indium oxide), lanthanide metal-doped indium oxide, antimony-doped tin oxide, etc. It can be understood that the substrate structure can use glass as a substrate, and a transparent flexible substrate structure can also be used. Specifically, the material of the transparent flexible substrate structure can be, for example, an organic polymer material, which can be mixed by one or more of the following materials in different proportions: polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), polydimethylsiloxane (PDMS).

[0101] In some embodiments, in addition to the material of the other electrode layer serving as the transparent electrode comprising a conductive material, the conductive material further comprises one or more of a transparent conductive metal oxide, a carbon material, a metal, and alloys thereof. Optionally, the transparent conductive metal oxide is as defined above; the metal and alloy thereof comprise one or more of Au, Ag, Cu, Al, Ni, Cr, Bi, Pt, Mg, Mo, W, and alloys thereof; and the carbon material comprises one or more of graphite, graphene, and carbon nanotubes. Optionally, the conductive material comprises one or more of Ag, Cu, C, Au, Al, ITO, AZO, BZO, or IZO, and further optionally comprises one or more of Cu, Ag, and Au.

[0102] In some embodiments, the first electrode layer is a transparent electrode, which is an electrode for first receiving incident light.

[0103] In some embodiments, the perovskite cell may further include one or both of an electron transport layer and a hole transport layer, wherein the electron transport layer and the hole transport layer are respectively located on both sides of the perovskite layer, for transporting and extracting electrons and holes, thereby improving the photoelectric conversion efficiency of the perovskite cell. It is understood that the perovskite cell may include both an electron transport layer and a hole transport layer, in which case the electron transport layer and the hole transport layer are respectively located on both sides of the perovskite layer; it is also understood that the perovskite cell may include only one of the electron transport layer and the hole transport layer, such as the electron transport layer, which is located on one side of the perovskite layer. Furthermore, in the case where the perovskite cell includes a first electrode layer and a second electrode layer, the electron transport layer and the hole transport layer are disposed between the first electrode layer and the second electrode layer. In some embodiments, the perovskite cell includes a substrate structure, a first electrode layer, a hole transport layer, a perovskite layer, an electron transport layer, and a second electrode layer stacked in sequence, and the first electrode layer is a transparent electrode; in other embodiments, the perovskite cell includes a substrate structure, a first electrode layer, an electron transport layer, a perovskite layer, a hole transport layer, and a second electrode layer stacked in sequence, and the first electrode layer is a transparent electrode.

[0104] The present application does not specifically limit the hole transport material used in the hole transport layer, and the electron transport material commonly used in the art can be used. Without limitation, the hole transport material can include but is not limited to one or more of the following hole transport materials and their derivatives: 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), methoxytriphenylamine-fluoroformamidine, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly(3,4-ethylenedioxythiophene): polystyrene sulfonic acid, poly-3-hexylthiophene, triptycene The core of the present invention is triphenylamine, 3,4-ethylenedioxythiophene-methoxytriphenylamine, N-(4-phenylamino)carbazole-spirobifluorene, polythiophene, phosphoric acid-based monomers, carbazole-based monomers, sulfonic acid-based monomers, triphenylamine-based monomers, aromatic monomers, metal oxides (which can be recorded as first metal oxides), cuprous iodide and cuprous thiocyanate. The metal element in the first metal oxide can include one or more of Ni, Mo, W and Cu, for example, nickel oxide (NiO x ), WO3.

[0105] The present application does not specifically limit the electron transport material used in the electron transport layer, and the electron transport materials commonly used in the art can be used. For example, the electron transport material includes one or more of fullerene and its derivatives, imide compounds, metal oxides, metal sulfides, metal fluorides, cyano-containing polyphenylene vinylene, boron-containing polymers, bathocuproin, red phenanthroline, hydroxyquinoline aluminum, oxadiazole compounds, and quinone compounds. Exemplarily, fullerene and its derivatives include one or more of fullerene C60, fullerene C70, PCBM ([6,6]-phenyl-C61-butyric acid methyl ester), [6,6]-phenyl C71 butyric acid methyl ester (PC71BM); imide compounds include one or more of perylene imide materials, naphthalimide materials, phthalimide, succinimide, N-bromosuccinimide, glutarimide or maleimide; the metal element in the metal oxide can be Including one or more of Mg, Ni, Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga and Cr, such as one or more of tin oxide (SnO2), zinc oxide (ZnO), titanium oxide; metal sulfides such as indium sulfide or zinc sulfide; metal fluorides such as one or more of lithium fluoride (LiF), sodium fluoride, magnesium fluoride (MgF2), calcium fluoride (CaF2).

[0106] In some embodiments, the perovskite cell may further include other functional layers, such as a passivation layer for passivating defects in the perovskite layer, or a hole blocking layer for blocking hole transport, etc., which are not limited here.

[0107] The sixth aspect of the present application provides a method for preparing a perovskite battery, which includes a perovskite layer, comprising the following steps: preparing a lead iodide solution according to the preparation method of the lead iodide solution of the first aspect of the present application, and using the prepared lead iodide solution as a raw material for a perovskite precursor solution; or using the lead iodide adduct prepared by the preparation method of the lead iodide adduct of the third aspect of the present application as a raw material to prepare the perovskite layer.

[0108] In some embodiments, the perovskite battery further includes a first electrode layer, an electron transport layer or a hole transport layer, a second electrode layer and other film layers. The structure of the perovskite battery is as exemplified above and is not limited here.

[0109] The above-mentioned first electrode layer, hole transport layer, electron transport layer and second electrode layer can be prepared by commonly used preparation methods in the field, including but not limited to solution method and solid deposition method. The solution method includes any one of spin coating, spray coating, blade coating and slit coating, and the solid deposition method includes any one of vacuum evaporation, sputtering deposition, plasma deposition, ion deposition and atomic layer deposition (ALD).

[0110] The seventh aspect of the present application provides a photovoltaic component, comprising the perovskite cell of the fifth aspect of the present application.

[0111] The above-mentioned photovoltaic module includes one or more perovskite cells, which can be selected according to the specific application scenario; further, the above-mentioned photovoltaic module includes multiple perovskite cells, and the multiple perovskite cells are connected in series or in parallel to form a cell sheet.

[0112] In some embodiments, the photovoltaic module further includes a photovoltaic glass layer, an adhesive layer, and a back sheet.

[0113] Adhesive layers are provided on both surfaces of the cell, a back plate is provided on the surface of one of the adhesive layers away from the cell, and a photovoltaic glass layer is provided on the surface of the other adhesive layer away from the cell.

[0114] The photovoltaic glass layer and back panel are used to protect the perovskite cells, and have the functions of sealing, insulation and waterproofing; the bonding layer serves to bond the photovoltaic glass layer to the cell, and to bond the back panel to the cell.

[0115] Optionally, the photovoltaic glass layer is made of tempered glass, the back panel is made of TPT (polyvinyl fluoride) or TPE (thermoplastic elastomer), and the adhesive layer is made of EVA (polyethylene-polyvinyl acetate copolymer).

[0116] Furthermore, the photovoltaic module further includes a junction box and an outer frame.

[0117] The junction box is used to protect the power generation system of the entire photovoltaic module. It is equivalent to a current transfer station. When a battery cell short-circuits, the junction box will automatically disconnect the short-circuited battery string.

[0118] The outer frame can support and protect the entire photovoltaic module. The frame can be made of aluminum alloy, which has excellent strength and corrosion resistance.

[0119] Furthermore, silicone is used to bond and seal the connection between the frame and other parts of the photovoltaic module. Photovoltaic modules can convert solar energy into electrical energy, which can be stored in batteries or used to drive loads.

[0120] In some embodiments, the photovoltaic component is a solar panel.

[0121] An eighth aspect of the present application provides a photovoltaic system comprising the above-mentioned photovoltaic assembly.

[0122] The photovoltaic system utilizes the perovskite cells in the above-mentioned photovoltaic modules to directly convert solar radiation energy into electrical energy with high efficiency and good stability; further, the above-mentioned photovoltaic system is a photovoltaic power generation system.

[0123] Photovoltaic modules are the core part of photovoltaic power generation systems. The above photovoltaic system includes one or more photovoltaic modules, which can be selected according to the specific application scenario; further, when the above photovoltaic system includes multiple photovoltaic modules, the multiple photovoltaic modules form a photovoltaic array.

[0124] The above photovoltaic system can be an independent photovoltaic power generation system or a grid-connected photovoltaic power generation system.

[0125] An independent photovoltaic power generation system consists of a photovoltaic array, a battery pack, a charge controller, a power electronic converter (inverter), and a load. Its operating principle is that solar radiation energy is first converted into electrical energy by the photovoltaic array, then converted by the power electronic converter to power the load. Meanwhile, excess electrical energy is stored as chemical energy in an energy storage device after passing through the charge controller. In this way, when sunlight is insufficient, the energy stored in the battery can be converted into 220V, 50Hz AC electricity after passing through the power electronic inverter, filtering, and power frequency transformer to supply the AC load.

[0126] A grid-connected photovoltaic power generation system consists of a photovoltaic array, a high-frequency DC / DC boost circuit, a power electronic converter (inverter), and system monitoring. Its operating principle is that solar radiation energy is converted by the photovoltaic array, then converted to high-voltage DC through high-frequency DC conversion. This is then inverted by a power electronic inverter and output to the grid as a sinusoidal AC current with a frequency consistent with the grid voltage.

[0127] The above two photovoltaic power generation systems have their own characteristics and can be selected according to specific application scenarios.

[0128] Please refer to FIG1 . A ninth aspect of the present application provides an electrical device, which includes the photovoltaic system described above.

[0129] In some embodiments, the power-consuming device is a common device that includes the perovskite cell of the present application, such as those used in the communications, transportation, agriculture, and lighting fields. Examples of such devices include satellites, communications equipment, traffic lights, lighthouses, wireless phone booths, oil drilling monitoring equipment, power supply systems, camping lanterns, electric vehicles, electronic device chargers, and building curtain walls. The following describes embodiments of the present application.

[0130] The examples described below are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention. Where specific techniques or conditions are not specified in the examples, the methods or conditions described in the literature within the art or in the product specifications were used. Where the manufacturer of the reagents or instruments is not specified, all are commercially available conventional products.

[0131] Example 1:

[0132] 1) Preparation of substrate

[0133] The etched FTO transparent metal oxide substrate was cleaned with 2% by mass Triton X-100 deionized water solution, anhydrous ethanol solution, deionized water solution, and anhydrous ethanol solution in sequence. The cleaned substrate was dried and then irradiated in a UV ozone machine for 20 minutes.

[0134] 2) Preparation of hole transport layer

[0135] Nickel oxide nanoparticles were dissolved in deionized water to form a solution with a concentration of 15 mg / mL. The nickel oxide nanoparticle solution was spin-coated on a UV-ozone treated substrate at a rotation speed of 5000 rpm for 30 seconds. The substrate was then annealed on a hot plate at 150°C for 10 minutes to form a hole transport layer on the substrate, thereby obtaining a substrate containing a hole transport layer with a thickness of 6 nm.

[0136] 3) Preparation of perovskite layer

[0137] Dissolve 380 mg (1.5 mmol) of iodine and 310.8 mg (1.5 mmol) of lead in 800 μL of a mixed polar solvent of N,N-dimethylformamide (DN value is 26.6) and 200 μL of dimethyl sulfoxide (DN value is 29.8), the mass volume ratio of iodine to the mixed polar solvent is 0.38 mg / μL, and stir for 6 hours to obtain a PbI2 solution.

[0138] 1 mL of the prepared PbI2 solution was added to 245 mg (1.425 mmol) of formamidine hydroiodide and 19.5 mg (0.075 mmol) of cesium iodide and stirred for half an hour to obtain a perovskite precursor solution.

[0139] Under a nitrogen atmosphere, the perovskite precursor solution was dropwise added to the substrate containing the hole transport layer. Spin coating was performed at 1000 rpm for 10 seconds, followed by 5000 rpm for 30 seconds, with 150 μL of chlorobenzene injected as an antisolvent. The resulting film was annealed at 150°C for 10 minutes, yielding a 600 nm thick perovskite film.

[0140] 4) Preparation of electron transport layer and electrode layer

[0141] The perovskite film was sequentially evaporated under high vacuum onto 25nm thick C60, 7nm thick bathocuprol and 100nm thick copper electrode to obtain a perovskite cell.

[0142] Example 2:

[0143] This embodiment is basically the same as Example 1, except that: in step 3), the polar solvent is a mixed polar solvent of tetrahydrofuran (THF, DN value is 20) and dimethyl sulfoxide (DMSO, DN value is 29.8), the volume fraction of tetrahydrofuran in the mixed polar solvent is x, the volume fraction of dimethyl sulfoxide is y, and y / x is 0.1.

[0144] Example 3:

[0145] This embodiment is basically the same as Example 1, except that: in step 3), the polar solvent is a mixed polar solvent of tetrahydrofuran (THF, DN value is 20) and dimethyl sulfoxide (DMSO, DN value is 29.8), the volume fraction of tetrahydrofuran in the mixed polar solvent is x, the volume fraction of dimethyl sulfoxide is y, and y / x is 0.25.

[0146] Example 4:

[0147] This embodiment is basically the same as Example 1, except that: in step 3), the polar solvent is a mixed polar solvent of tetrahydrofuran (THF, DN value is 20) and dimethyl sulfoxide (DMSO, DN value is 29.8), the volume fraction of tetrahydrofuran in the mixed polar solvent is x, the volume fraction of dimethyl sulfoxide is y, and y / x is 0.4.

[0148] Example 5:

[0149] This embodiment is basically the same as Example 1, except that: in step 3), the polar solvent is a mixed polar solvent of tetrahydrofuran (THF, DN value 20) and hexamethylphosphoric triamide (HMPA, DN value 38.8), the volume fraction of tetrahydrofuran in the mixed polar solvent is x, the volume fraction of hexamethylphosphoric triamide is y, and y / x is 0.015.

[0150] Example 6:

[0151] This embodiment is basically the same as Example 1, except that: in step 3), the polar solvent is a mixed polar solvent of tetrahydrofuran (THF, DN value 20) and hexamethylphosphoric triamide (HMPA, DN value 38.8), the volume fraction of tetrahydrofuran in the mixed polar solvent is x, the volume fraction of hexamethylphosphoric triamide is y, and y / x is 0.045.

[0152] Example 7:

[0153] This embodiment is basically the same as Example 1, except that: in step 3), the polar solvent is a mixed polar solvent of tetrahydrofuran (THF, DN value 20) and hexamethylphosphoric triamide (HMPA, DN value 38.8), the volume fraction of tetrahydrofuran in the mixed polar solvent is x, the volume fraction of hexamethylphosphoric triamide is y, and y / x is 0.08.

[0154] Example 8:

[0155] This embodiment is basically the same as Example 1, except that: in step 3), the polar solvent is a mixed polar solvent of tetrahydrofuran (THF, DN value is 20) and ethylenediamine (EDA, DN value is 55), the volume fraction of tetrahydrofuran in the mixed polar solvent is x, the volume fraction of ethylenediamine is y, and y / x is 0.01.

[0156] Example 9:

[0157] This embodiment is basically the same as Example 1, except that: in step 3), the polar solvent is a mixed polar solvent of tetrahydrofuran (THF, DN value is 20) and ethylenediamine (EDA, DN value is 55), the volume fraction of tetrahydrofuran in the mixed polar solvent is x, the volume fraction of ethylenediamine is y, and y / x is 0.03.

[0158] Example 10:

[0159] This embodiment is basically the same as Example 1, except that: in step 3), the polar solvent is a mixed polar solvent of tetrahydrofuran (THF, DN value is 20) and ethylenediamine (EDA, DN value is 55), the volume fraction of tetrahydrofuran in the mixed polar solvent is x, the volume fraction of ethylenediamine is y, and y / x is 0.045.

[0160] Example 11:

[0161] This embodiment is basically the same as embodiment 1, with the only difference being that in step 3), the polar solvent used is N,N-dimethylformamide, whose DN value is 26.6.

[0162] Example 12:

[0163] This embodiment is substantially the same as embodiment 1, except that in step 3), the polar solvent used is a mixed polar solvent of 800 μL N,N-dimethylformamide (DN value 26.6) and 200 μL hexamethylphosphoric triamide (HMPA, DN value 38.8).

[0164] Example 13:

[0165] This embodiment is substantially the same as embodiment 1, except that in step 3), the polar solvent is a mixed polar solvent of 800 μL N,N-dimethylformamide (DN value 26.6) and 200 μL triethylamine (THA, DN value 61).

[0166] Example 14:

[0167] This embodiment is substantially the same as embodiment 1, except that in step 3), the solvent comprises a mixed solvent of 600 μL N,N-dimethylformamide (DN value is 26.6) and 400 μL acetonitrile (CAN, DN value is 14).

[0168] Example 15:

[0169] This embodiment is substantially the same as embodiment 1, except that: in step 3), the amount of lead used is 373.0 mg (1.8 mmol), the amount of iodine used is 380 mg (1.5 mmol), and the molar ratio of lead to iodine is 1.2:1; after the reaction is completed, solid impurities are removed by filtration.

[0170] Example 16:

[0171] This embodiment is substantially the same as embodiment 1, except that: in step 3), the amount of lead used is 466.2 mg (2.25 mmol), the amount of iodine used is 380 mg (1.5 mmol), and the molar ratio of lead to iodine is 1.5:1; after the reaction is completed, solid impurities are removed by filtration.

[0172] Example 17:

[0173] This embodiment is substantially the same as embodiment 1, except that in step 3), the mass volume ratio of elemental iodine to the mixed polar solvent is 0.51 mg / μL; the volume of the mixed polar solvent is 745 μL, and the mixed volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 4:1.

[0174] Example 18:

[0175] This embodiment is basically the same as Example 1, except that: after the PbI2 solution is prepared in step 3), 8 mg of Lewis base ligand 1,1,3,3-tetramethylurea (TMU) is added to 1 mL of the PbI2 solution prepared above and stirred to dissolve, wherein the donor number DN is 30.6, and the mass volume ratio of the Lewis base ligand to the PbI2 solution is 8 mg / mL; then the solution is added to 245 mg (1.425 mmol) of formamidine hydroiodide and 19.5 mg (0.075 mmol) of cesium iodide, and stirred for half an hour to obtain a perovskite precursor solution.

[0176] Example 19:

[0177] This embodiment is basically the same as Example 18, except that the Lewis base ligand added in step 3) is tetramethylthiourea (TMTU), whose donor number DN is 31.8, and the mass volume ratio of the Lewis base ligand to the PbI2 solution is 4.5 mg / mL.

[0178] Example 20:

[0179] This embodiment is basically the same as Example 18, except that the Lewis base ligand added in step 3) is 1,3-dimethylbarbituric acid (DMBA), whose donor number DN is 33.6, and the mass volume ratio of the Lewis base ligand to the PbI2 solution is 9.6 mg / mL.

[0180] Example 21:

[0181] This embodiment is basically the same as Example 18, except that in step 3), the amount of Lewis base ligand added is 16 mg, and the mass volume ratio of Lewis base ligand to PbI2 solution is 16 mg / mL.

[0182] Example 22:

[0183] This embodiment is basically the same as Example 18, except that: in step 3), the amount of Lewis base ligand added is 32 mg, and the mass volume ratio of Lewis base ligand to PbI2 solution is 32 mg / mL.

[0184] Comparative Example 1:

[0185] This comparative example is basically the same as Example 1, except that: in step 3), commercially available solid lead iodide is used as a lead source in the perovskite precursor solution with a purity of 99.5%; specifically, 245 mg (1.425 mmol) of formamidine hydroiodide, 19.5 mg (0.075 mmol) of cesium iodide, and 691.51 mg (1.5 mmol) of the above-mentioned lead iodide are dissolved in 800 μL of N,N-dimethylformamide and 200 μL of dimethyl sulfoxide, and stirred for 30 minutes to obtain a perovskite precursor solution.

[0186] Comparative Example 2:

[0187] An equal volume of acetonitrile (CAN, DN 14) was used instead of the N,N-dimethylformamide and dimethyl sulfoxide mixed polar solvent in step 3) of Example 1. The mass volume ratio of elemental iodine to acetonitrile was 0.38 mg / μL. After stirring for 6 hours, essentially no reaction occurred. Therefore, no perovskite cell was prepared in this comparative example.

[0188] Comparative Example 3:

[0189] This comparative example is basically the same as Example 1, except that: the perovskite solution in Comparative Example 3 uses commercially available high-purity solid lead iodide as a lead source, and the purity of the solid lead iodide is 99.999%; 245 mg (1.425 mmol) of formamidine hydroiodide, 19.5 mg (0.075 mmol) of cesium iodide and 691.51 mg (1.5 mmol) of lead iodide (purity is 99.999%) are dissolved in 800 μL of DMF and 200 μL of DMSO and stirred for 30 minutes to obtain a perovskite precursor solution.

[0190] Test method:

[0191] 1) Test method for compound donor number DN

[0192] The concentration of sodium chlorate is 0.2M in the corresponding solvent. 23 The DN value of the corresponding solvent can be inferred by Na NMR (J. Am. Chem. Soc. 1971, 93, 22, 5620-5623, each test spectrum is tested 3 times to obtain the average value).

[0193] 2) Purity test method of lead iodide adduct

[0194] The lead iodide solution was vacuum dried to obtain a lead iodide adduct, and its purity was tested (calculated as cations) using inductively coupled plasma-chromatography (ICP-IC).

[0195] 3) Test methods for open circuit voltage, short circuit current, fill factor and photoelectric conversion efficiency of perovskite cells

[0196] A Keithley 2400 source meter was used to measure the AM1.5G (100mW / cm 2 ) JV test was conducted under a solar simulator. Before the test, the light intensity was calibrated using a standard silicon cell. The device active area is 0.09cm 2 , the scan rate is 50 mV·s -1 .

[0197] 4) Perovskite battery stability test method

[0198] At 85°C, an LED lamp calibrated to 1 sunlight was used to test the stability of the packaged perovskite cell. The changes in cell efficiency were continuously monitored at the maximum output voltage. When the test efficiency decayed to 80% of the original value, it was recorded as T 80 . T 80 The larger the value of , the better the stability of the perovskite battery, and vice versa.

[0199] The preparation parameters and purity of the lead iodide solutions of the above embodiments and comparative examples are shown in Table 1, and the performance data of the perovskite battery are shown in Table 2.

[0200] Table 1

[0201] Table 2

[0202] As shown in Table 1 and Table 2, lead iodine and iodine are mixed in a solvent system including a polar solvent to prepare lead iodide solution and lead iodide adducts. The purity of the lead iodide adducts prepared in each embodiment of the present application is higher, and the photoelectric conversion efficiency of the perovskite battery of each embodiment is higher and the stability is better. In Comparative Example 1, commercially available solid lead iodide with lower purity is used, and the photoelectric conversion efficiency of the perovskite battery prepared by it is significantly reduced, and stability is also reduced. In Comparative Example 2, acetonitrile with a smaller donor number DN value is used as a solvent when preparing lead iodide solution, and iodine and lead are substantially unreacted. In Comparative Example 3, commercially available high-purity solid lead iodide is used, and the photoelectric conversion rate of the perovskite battery prepared by Examples 1 and 15-21 of the present application is better than the perovskite battery prepared by the high-purity lead iodide of Comparative Example 3, but the cost of lead iodide is significantly reduced. Although the performance of the perovskite cells prepared in other embodiments is lower than that of Comparative Example 3, it is still better than that of Comparative Example 2. Whether in terms of cost or process simplicity, the solution of the present application still has certain advantages in industrial production.

[0203] The above description of the various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced with each other and will not be repeated herein for the sake of brevity.

[0204] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for preparing a lead iodide solution, comprising the following steps: Lead and iodine are mixed and reacted in a solvent system comprising a polar solvent to form a lead iodide solution, wherein the donor number of the polar solvent is greater than or equal to 20.

2. The preparation method of lead iodide solution according to claim 1, wherein The donor number of the polar solvent is 20-61.

3. The preparation method of lead iodide solution according to claim 2, wherein The donor number of the polar solvent is 24-40.

4. The preparation method of the lead iodide solution according to any one of claims 1 to 3, wherein The polar solvent includes a first polar solvent and a second polar solvent. The donor number of the first polar solvent is DN1, 20≤DN1<24; the donor number of the second polar solvent is DN2, and DN2>DN1.

5. The preparation method of lead iodide solution according to claim 4, wherein 27≤DN2<34; the volume fraction of the first polar solvent in the solvent system is x, the volume fraction of the second polar solvent is y, and 0.1≤y / x≤0.

4.

6. The preparation method of lead iodide solution according to claim 4, wherein 34≤DN2<50; the volume fraction of the first polar solvent in the solvent system is x, the volume fraction of the second polar solvent is y, and 0.015≤y / x≤0.

08.

7. The preparation method of lead iodide solution according to claim 4, wherein 50≤DN2<61; the volume fraction of the first polar solvent in the solvent system is x, the volume fraction of the second polar solvent is y, and 0.01≤y / x≤0.

045.

8. The preparation method of the lead iodide solution according to any one of claims 1 to 7, wherein The solvent system includes the polar solvent and a second solvent, wherein the donor number of the second solvent is less than 20; and the volume content of the second solvent in the solvent system is not greater than the volume content of the polar solvent.

9. The preparation method of lead iodide solution according to claim 8, wherein The second solvent includes one or more of acetonitrile, 2-methylpropionitrile, N,N-dimethyltrifluoroacetamide, benzaldehyde and acetone.

10. The method for preparing the lead iodide solution according to any one of claims 1 to 9, wherein The polar solvent includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, tetramethylurea, 1,3-dimethyl-2-imidazolidinone, 1,3-dimethylpropyleneurea, ethylenediamine and hexamethylphosphoric triamide.

11. The method for preparing the lead iodide solution according to any one of claims 1 to 10, wherein The molar ratio of the lead element to the iodine element is greater than or equal to 1:

1.

12. The method for preparing lead iodide solution according to claim 11, wherein The molar ratio of the lead element to the iodine element is 1-1.5:

1.

13. The method for preparing the lead iodide solution according to any one of claims 1 to 12, wherein After the mixing reaction is completed, the preparation method further comprises the step of filtering the obtained reaction solution to obtain a filtrate.

14. The method for preparing the lead iodide solution according to any one of claims 1 to 13, wherein The mixing reaction time is not less than 6 hours.

15. The method for preparing the lead iodide solution according to claim 14, wherein The mixing reaction time is 6h-10h.

16. The method for preparing the lead iodide solution according to any one of claims 1 to 15, wherein The temperature of the mixing reaction is 0°C-60°C.

17. The method for preparing the lead iodide solution according to any one of claims 1 to 16, wherein The mass volume ratio of the iodine element to the solvent system is 0.04 mg / μL-0.56 mg / μL.

18. The method for preparing the lead iodide solution according to any one of claims 1 to 17, wherein After the mixing reaction is completed, the preparation method further comprises the step of mixing the obtained reaction solution with a Lewis base ligand, wherein the donor number of the Lewis base ligand is greater than the donor number of the polar solvent.

19. The method for preparing the lead iodide solution according to claim 18, wherein: The donor number of the Lewis base ligand is 20.1-61.

1.

20. The method for preparing the lead iodide solution according to claim 19, wherein: The donor number of the Lewis base ligand is 26-40.

21. The method for preparing the lead iodide solution according to any one of claims 18 to 20, wherein: The Lewis base ligand includes one or more of urea, N-methylurea, 1,1-dimethylurea, trimethylurea, 1,1,3,3-tetramethylurea, 1,3-dimethyl-2-imidazolidinone, 6-amino-3-methyluracil, 1,3-dimethylbarbituric acid, thiourea, N-methylthiourea, 1,1-dimethylthiourea, trimethylthiourea, 1,1,3,3-tetramethylthiourea, N-methylpyrrolidone and dimethyl sulfoxide.

22. The method for preparing the lead iodide solution according to any one of claims 18 to 21, wherein: The mass volume ratio of the Lewis base ligand to the reaction solution is 0.9 mg / mL-600 mg / mL.

23. A lead iodide solution prepared by the method for preparing the lead iodide solution according to any one of claims 1 to 22.

24. A method for preparing a lead iodide adduct, comprising filtering a lead iodide solution prepared by the method for preparing a lead iodide solution according to any one of claims 1 to 22, collecting a filtrate, and drying and crystallizing the filtrate to obtain the lead iodide adduct.

25. A lead iodide adduct prepared by the method for preparing the lead iodide adduct according to claim 24.

26. A perovskite battery comprising a perovskite layer, wherein the raw materials for preparing the perovskite layer comprise one or more of the lead iodide solution prepared by the method for preparing the lead iodide solution according to any one of claims 1 to 22 or the lead iodide adduct prepared by the method for preparing the lead iodide adduct according to claim 24.

27. A method for preparing a perovskite battery, wherein the perovskite battery comprises a perovskite layer, comprising the following steps: A lead iodide solution is prepared according to the method for preparing a lead iodide solution according to any one of claims 1 to 22, and the prepared lead iodide solution is used as a raw material for a perovskite precursor solution, or the lead iodide adduct prepared by the method for preparing a lead iodide adduct according to claim 24 is used as a raw material to prepare a perovskite layer.

28. A photovoltaic module comprising the perovskite cell according to claim 26.

29. A photovoltaic system comprising the photovoltaic module according to claim 28.

30. An electrical device comprising the photovoltaic system according to claim 29.

31. A power generation device comprising the photovoltaic system according to claim 29.

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