Perovskite material and preparation method thereof, perovskite device and photovoltaic module

Abstract

The invention relates to the technical field of photoelectric materials, in particular to a perovskite material and a preparation method thereof, a perovskite device and a photovoltaic module. The perovskite material has a three-dimensional structure, the chemical general formula of the perovskite material is ABX3, A is an A-site cation, B is a B-site cation, and X is an X-site anion; wherein the A-site cations comprise at least five different types of cations, one type of A-site cations is formamidine cations, and the other types of A-site cations comprise a first type of A-site cations with the ion radius smaller than that of the formamidine cations and a second type of A-site cations with the ion radius larger than that of the formamidine cations; in the A-site cations, the atomic percentage of the first type of A-site cations is greater than the atomic percentage of the second type of A-site cations, and in the A-site cations, the atomic percentage of the formamidine cations is 50%-90%.

Description

Technical Field

[0001] This application relates to the technical field of optoelectronic materials, and particularly to a perovskite material, a preparation method thereof, a perovskite device, and a photovoltaic module. Background Art

[0002] Perovskite materials have become a research hotspot in fields such as the photovoltaic industry due to their unique optoelectronic properties. However, in practical applications, it is difficult to simultaneously balance the stability of perovskite materials and the degree of homogeneity of the material composition. For example, although some technical means can improve the stability of the perovskite bulk phase to a certain extent, it is still prone to the problem of perovskite phase segregation, resulting in poor uniformity of the entire perovskite system. Summary of the Invention

[0003] To solve the above technical problems, this application discloses a perovskite material, a preparation method thereof, a perovskite device, and a photovoltaic module, which improve the structural stability and material homogeneity when the perovskite material is used as a light-absorbing material through optimization of the perovskite material.

[0004] In a first aspect, this application provides a perovskite material. The perovskite material has a three-dimensional structure, and the chemical general formula of the perovskite material is ABX 3 , where A is a cation at the A-site, B is a cation at the B-site, and X is an anion at the X-site;

[0005] Among them, the cation at the A-site includes at least five different types of cations. One type of cation at the A-site is a formamidinium cation, and other types of cations at the A-site include a first type of A-site cation with an ionic radius smaller than that of the formamidinium cation and a second type of A-site cation with an ionic radius larger than that of the formamidinium cation; among the cations at the A-site, the atomic percentage of the first type of A-site cation is greater than that of the second type of A-site cation, and among the cations at the A-site, the atomic percentage of the formamidinium cation is 50% - 90%.

[0006] Further, the first type of A-site cation includes at least two.

[0007] Further, the band gap of the perovskite material is 1.65 eV - 1.8 eV.

[0008] Further, the atomic percentage of the second type of A-site cation in the cations at the A-site is less than or equal to 10%.

[0009] Further, the anion at the X-site includes at least three different types of halogen anions and / or pseudohalogen anions, where one type of anion at the X-site is I - , and other types of anions at the X-site include an ionic radius smaller than that of the I -a first type of X-site anion with an ionic radius greater than that of the I - a second type of X-site anion with an ionic radius less than that of the I, where the first type of X-site anion includes at least one kind, and the second type of X-site anion includes at least one kind; among the X-site anions, the atomic percentage of the first type of X-site anion is greater than that of the second type of X-site anion.

[0010] Furthermore, the first type of A-site cation includes MA + , Cs + , K + , Ca 2+ , Zn 2+ , Na + or Rb + and at least two of them; and / or,

[0011] the second type of A-site cation includes DMA + , BA + , PA + , AA + , BMIM + , EA + or EDA 2+ and at least one of them; and / or,

[0012] the B-site cation includes Pb 2+ , Sn 2+ and at least one of them; and / or,

[0013] the X-site anion includes I - , a first type of X-site anion with an ionic radius less than that of the I - , a second type of X-site anion with an ionic radius greater than that of the I - , the first type of X-site anion includes F - , Br - , Cl - and at least one of them, the second type of X-site anion includes SCN - , OCN - , BF 4 - , TFSI - , CF 3 - , CF 3 CO 2 - , COO - or SO 3 H - and at least one of them, among the X-site anions, the atomic percentage of the I - is greater than or equal to 50%.

[0014] Further, the chemical formula of the perovskite material is (FA a1 DMA a2 MA a3 PA a4 Cs a5 Rb a6 )PbI 3 , where a1:a2:a3:a4:a5:a6 = (50 - 90):(0.5 - 5):(3 - 22):(1 - 6):(1 - 16):(0.5 - 10); or,

[0015] The chemical formula of the perovskite material is (FA a1 DMA a2 MA a3 PA a4 Cs a5 Rb a6 )Pb(I b1 Cl b2 Br b3 ), where a1:a2:a3:a4:a5:a6 = (50 - 90):(0.5 - 5):(3 - 22):(1 - 6):(1 - 16):(0.5 - 10), and b1:b2:b3 = (70 - 95):(0.5 - 8):(3 - 25); or,

[0016] The chemical formula of the perovskite material is (FA a1 DMA a2 MA a3 PA a4 Cs a5 Rb a6 )Pb(I b1 Cl b2 Br b3 OCN b4 SCN b5 ), where a1:a2:a3:a4:a5:a6 = (50 - 90):(0.5 - 5):(3 - 22):(1 - 6):(1 - 16):(0.5 - 10), and b1:b2:b3:b4:b5 = (70 - 90):(0.5 - 6):(2 - 20):(0.5 - 8):(0.5 - 8).

[0017] In a second aspect, the present application provides a preparation method of the perovskite material as described in the first aspect. The preparation method of the perovskite material includes the following steps:

[0018] Coat a cation solution on the framework layer, and anneal to obtain the perovskite material;

[0019] Among them, the framework layer at least includes the B-site cations and the X-site anions, and the cation solution includes part or all of the A-site cations.

[0020] Further, the surface of the framework layer has a suede structure; and / or,

[0021] The film thickness of the perovskite material is 500 nm to 2000 nm; and / or,

[0022] The A-site cations are divided into alkali metal cations and organic cations. Before the step of coating the cation solution on the framework layer, the preparation method of the perovskite material further includes the following steps:

[0023] Preparing the framework layer: Co-evaporating a material source containing the alkali metal cations, a material source containing the B-site cations, and a material source containing the X-site anions by evaporation coating to obtain the framework layer;

[0024] Preparing the cation solution: Dissolving the organic cations in an organic solvent.

[0025] Further, PbI 2 , CsBr and RbBr are co-evaporated at an evaporation rate ratio of (8 - 12):(0.5 - 2.2):(0.1 - 1.2) to obtain a lead iodide framework layer containing alkali metal inorganic salts, and the thickness of the framework layer is 300 nm to 750 nm; and / or,

[0026] In the step of preparing the cation solution, FAI, DMAI, MAI, MACl and PACl are dissolved in isopropanol according to an atomic percentage of (70 - 90):(3 - 12):(8 - 12):(8 - 22):(3 - 12) to obtain the cation solution; and / or,

[0027] In the step of preparing the cation solution, the organic solvent includes at least one of ethanol and isopropanol; and / or,

[0028] In the step of coating the cation solution on the framework layer, coating is carried out according to an atomic percentage of FA + :DMA + :MA + :PA + :Cs + :Rb + of (70 - 90):(3 - 6):(6 - 18):(2 - 6):(4 - 6):(2 - 5).

[0029] In a third aspect, the present application provides a perovskite device, which includes the perovskite material as described in the first aspect, or the perovskite device includes the perovskite material prepared by the preparation method as described in the second aspect.

[0030] Further, the perovskite device includes at least one of a perovskite solar cell, a perovskite light-emitting diode, or a perovskite laser.

[0031] Further, the perovskite device is a perovskite tandem solar cell, and the perovskite tandem solar cell includes: a bottom cell with a planar or textured surface, an electron-hole recombination layer, a first transport layer, a perovskite light-absorbing layer, a second transport layer, and a transparent conductive layer that are sequentially disposed on the surface of the bottom cell, a first electrode in electrical contact with the transparent conductive layer, and a second electrode in electrical contact with the bottom cell; wherein, one of the first transport layer and the second transport layer is an electron transport layer and the other is a hole transport layer, one of the first electrode and the second electrode is a positive electrode and the other is a negative electrode, and the perovskite light-absorbing layer includes the perovskite material;

[0032] Alternatively, the perovskite device is a perovskite single-junction solar cell, and the perovskite single-junction solar cell includes: a transparent conductive substrate with a planar or textured surface, a first transport layer, a perovskite light-absorbing layer, and a second transport layer that are sequentially disposed on the transparent conductive substrate, a first electrode in electrical contact with the second transport layer, and a second electrode in electrical contact with the transparent conductive substrate; wherein, one of the first transport layer and the second transport layer is an electron transport layer and the other is a hole transport layer, one of the first electrode and the second electrode is a positive electrode and the other is a negative electrode, and the perovskite light-absorbing layer includes the perovskite material.

[0033] Further, the perovskite device is the perovskite tandem solar cell, and the bottom cell includes at least one of a crystalline silicon bottom cell, a copper indium gallium selenide bottom cell, a perovskite narrow-bandgap bottom cell, or an organic bottom cell; and / or,

[0034] The material of the electron-hole recombination layer includes at least one of IZO and ITO; and / or,

[0035] The thickness of the electron-hole recombination layer is 2 nm to 30 nm;

[0036] The material of the hole transport layer includes nickel oxide; and / or,

[0037] The thickness of the hole transport layer is 5 nm to 30 nm; and / or,

[0038] The thickness of the perovskite light-absorbing layer is 500 nm to 2000 nm; and / or,

[0039] The material of the electron transport layer includes C 60 ; and / or,

[0040] The thickness of the electron transport layer is 5 nm to 30 nm; and / or,

[0041] The material of the transparent conductive layer includes at least one of ITO, IZO, or IWO; and / or,

[0042] The thickness of the transparent conductive layer is 30 nm to 150 nm; and / or,

[0043] The material of the electrode includes at least one of gold, silver, copper, or aluminum; and / or,

[0044] The thickness of the electrode is 50 nm to 400 nm.

[0045] Further, the perovskite device is the perovskite tandem solar cell, and the perovskite tandem solar cell further includes:

[0046] A hole modification layer, disposed between the hole transport layer and the perovskite light-absorbing layer, the material of the hole modification layer being a single-molecule self-assembled material, and the single-molecule self-assembled material includes at least one of 2PACz, 4PACz, or MeO-2PACz; and / or,

[0047] A passivation layer, disposed between the perovskite light-absorbing layer and the second transport layer, the material of the passivation layer including LiF or a two-dimensional perovskite material, and the thickness of the passivation layer is 0.5 nm to 5 nm; and / or,

[0048] A buffer layer, disposed between the second transport layer and the transparent conductive layer, the thickness of the buffer layer being 5 nm to 30 nm; and / or,

[0049] An antireflection layer, disposed on a side of the transparent conductive layer facing away from the second transport layer, and the thickness of the antireflection layer is 80 nm to 150 nm.

[0050] In a fourth aspect, the present application provides a photovoltaic module, the photovoltaic module includes a solar cell, the solar cell includes a perovskite light-absorbing layer, the perovskite light-absorbing layer includes the perovskite material as described in the first aspect, or the perovskite light-absorbing layer includes the perovskite material prepared by the preparation method as described in the second aspect.

[0051] Compared with the prior art, the present application has at least the following beneficial effects:

[0052] The perovskite material disclosed in this application, through the coordinated control of the cation type, cation radius, and cation proportion of the three-dimensional perovskite material, ensures that while the entropy value of the perovskite material increases, the phase segregation problem of the perovskite material is effectively improved. Thus, it can not only improve the help effect on the bulk phase stability of the perovskite material due to the increase in entropy value, but also improve the phase segregation to make the three-dimensional perovskite material more uniform. From aspects such as the bulk phase stability degree and uniformity, the comprehensive performance of the perovskite material is effectively improved, which is conducive to improving the service life and optoelectronic conversion performance of devices using the perovskite material, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of this application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0054] Figure 1 It is a schematic structural diagram of a perovskite tandem solar cell in an embodiment of this application.

[0055] Description of the reference numerals in the drawings:

[0056] 1. Bottom cell; 2. Electron-hole recombination layer; 31. First transport layer; 32. Second transport layer; 4. Perovskite light-absorbing layer; 5. Transparent conductive layer; 61. First electrode; 62. Second electrode; 7. Hole modification layer; 8. Passivation layer; 9. Buffer layer; 10. Antireflection layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the drawings in the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, rather than all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application.

[0058] In this application, the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc. is the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe this application and its embodiments, and are not used to limit that the indicated devices, elements, or components must have a specific orientation, or be constructed and operated in a specific orientation.

[0059] Moreover, in addition to being used to indicate orientation or positional relationship, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0060] In addition, the terms "installed", "set up", "provided with", "connected", and "linked" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can be internal communication between two devices, components, or parts. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0061] In addition, terms such as "first", "second", etc. are mainly used to distinguish different devices, components, or parts (the specific species and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, components, or parts. Unless otherwise specified, the meaning of "a plurality" is two or more.

[0062] Perovskite materials have problems such as poor bulk stability and easy phase segregation, which limit their development in industrial applications. Taking three-dimensional perovskite materials as the light-absorbing layer of perovskite solar cells as an example, due to their poor bulk stability, it is easy to cause insufficient long-term stability of perovskite cells and affect the service life of perovskite cells. In some practices, modification techniques such as using additives or passivation layers are used to help improve the bulk stability of perovskite materials. However, since this does not essentially change the properties of perovskite materials themselves, the improvement of the bulk stability of perovskite materials is limited. In other practices, the entropy value of perovskite materials is increased by increasing the types of cations in perovskite materials, thereby improving the bulk stability of perovskite materials themselves.

[0063] However, the applicant has found that as the types of cations increase, the comprehensive stability of perovskite materials has not been significantly improved as expected. After a large number of exploratory studies, the applicant realized that although the increase in the types of cations is beneficial to increasing the entropy value of perovskite materials, the ionic radii, atomic diffusion coefficients, and formation energies of different cations vary greatly, resulting in obvious phase segregation problems in perovskite materials. That is, some components in the perovskite material are enriched in local areas, forming phases with different compositions from the overall composition. On the one hand, this leads to uneven stress distribution inside the perovskite crystal, which in turn still has a certain negative impact on the bulk phase stability of the perovskite material, resulting in the fact that the increase in entropy value does not have a significant effect on improving the stability of perovskite materials; on the other hand, it leads to differences in the physical and chemical properties of perovskite materials in different regions, that is, the uniformity of perovskite materials becomes worse, resulting in poor light absorption performance in local areas, which in turn affects the photoelectric conversion efficiency of perovskite solar cells.

[0064] Through in-depth analysis and research on perovskite materials, this application creatively proposes a perovskite material, its preparation method, perovskite device, and photovoltaic module. By synergistically controlling the types of cations, cationic radii, and cation ratios in three-dimensional perovskite materials, while ensuring an increase in the entropy value of perovskite materials, the phase segregation problem of perovskite materials is effectively improved. As a result, it is possible to not only improve the effect of the entropy value on the bulk phase stability of perovskite materials, but also improve the uniformity of three-dimensional perovskite materials due to the improvement of phase segregation, effectively improving the comprehensive performance of perovskite materials in terms of bulk phase stability and uniformity, etc., which is beneficial to improving the service life and photoelectric conversion performance of devices using perovskite materials.

[0065] First, an embodiment of this application provides a perovskite material. The perovskite material has a three-dimensional structure, and the chemical general formula of the perovskite material is ABX 3 , where A is the A-site cation, B is the B-site cation, and X is the X-site anion;

[0066] Among them, the A-site cations include at least five different types of cations. One type of A-site cation is formamidinium cation, and the other types of A-site cations include the first type of A-site cations with ionic radii smaller than that of the formamidinium cation and the second type of A-site cations with ionic radii larger than that of the formamidinium cation; among the A-site cations, the atomic percentage of the first type of A-site cations is greater than that of the second type of A-site cations, and among the A-site cations, the atomic percentage of the formamidinium cation is 50% - 90%.

[0067] According to the structural characteristics of perovskite materials, they can be divided into three-dimensional perovskite materials and two-dimensional perovskite materials. Among them, three-dimensional perovskite materials have better carrier transport properties and more suitable energy band structures, so they are more suitable as the light-absorbing layer; although the photoelectric conversion efficiency of two-dimensional perovskite materials is relatively low, they have higher stability than three-dimensional perovskite materials. Therefore, they are more suitable as the passivation layer, which is set on the surface of the light-absorbing layer of three-dimensional perovskite materials to provide better stability and surface protection for the light-absorbing layer.

[0068] The perovskite material of the embodiment of the present application has a three-dimensional structure, which is more suitable as a light-absorbing layer in perovskite devices to improve the photoelectric conversion efficiency. At the same time, the embodiment of the present application synergistically controls the types, ionic radii, proportions, etc. of A-site cations in the three-dimensional perovskite material. While improving the bulk stability of the perovskite material, it can effectively improve its phase segregation phenomenon to improve the uniformity of the perovskite material, thereby effectively improving the comprehensive stability of the perovskite material.

[0069] Among them, there are more than five types of A-site cations, which can increase the entropy value of the perovskite material and help the bulk phase of the three-dimensional perovskite to be more stable. However, for more than five types of cations, the atomic diffusion coefficients, ionic radii, and formation energies of various cations are often different. Although the bulk phase of the perovskite is more stable, problems such as A-site phase segregation and uneven material distribution are likely to occur. Therefore, the present application solves the above problems through the synergistic control of the ionic radius relationship, content ratio, etc. of various cations. Specifically, one of the A-site cations is formamidinium cation with an atomic proportion of 50% - 90%, and at least one of the other A-site cations is the first type of A-site cation (which can also be understood as a small-size A-site cation) with an ionic radius smaller than that of the formamidinium cation. By introducing the first type of A-site cation with an ionic radius smaller than that of the formamidinium cation, the tolerance factor of the three-dimensional perovskite material can be improved, lattice distortion can be reduced, and the stability of the perovskite material can be enhanced.

[0070] However, if all the other A-site cations are small-size A-site cations with an ionic radius smaller than that of the formamidinium cation, it is easy to cause A-site phase segregation. Therefore, there is at least one second type of A-site cation (which can also be understood as a large-size A-site cation) with an ionic radius larger than that of the formamidinium cation in the A-site cations of the present application. By introducing the second type of A-site cation with an ionic radius larger than that of the formamidinium cation, in addition to helping to further reduce the formation energy, it can also increase the steric hindrance and improve the A-site phase segregation problem caused by the addition of the small-size first type of A-site cation.

[0071] However, if all other A-site cations are large-sized A-site cations with an ionic radius larger than that of the formamidinium cation, or the proportion of such large-sized A-site cations is too high, it is likely to cause the perovskite material to change from a three-dimensional structure to a two-dimensional structure, or to a mixed structure mainly composed of a two-dimensional structure. Therefore, the A-site cation in the embodiment of the present application is mainly the formamidinium cation. By simultaneously introducing a first type of A-site cation and a second type of A-site cation, and controlling the atomic percentage of the first type of A-site cation in the A-site cations to be higher than that of the second type of A-site cation. Exemplarily, among the A-site cations, the atomic percentage of the formamidinium cation is 50%, 60%, 70%, 75%, 80%, 85% or 90%.

[0072] In this way, through the control and coordination of the selection types, ionic radius relationships, atomic percentages of the first type of A-site cation and the second type of A-site cation, etc. among the above A-site cations, while improving the bulk phase stability of the three-dimensional perovskite material, the phase segregation problem can be improved, the overall uniformity of the perovskite material can be improved, and the performance of the perovskite material can be more comprehensively improved.

[0073] It should be noted that the ionic radius reflects the size of the corresponding ion. For example, the ionic radius of I - is 220 pm, the ionic radius of Br - is 196 pm, the ionic radius of Cl - is 181 pm. Then, through the comparison of the ionic radii, it can be concluded that the size of the iodide ion > the size of the bromide ion > the size of the chloride ion.

[0074] In addition, the atomic percentage refers to the percentage of the number of atoms of a certain element in a chemical substance, and can also be understood as the proportion of the content of this element in this chemical substance. For example, there are 100 atoms in total at the A-site, among which 5 are MA + , 5 are Cs + , 5 are Rb + , 5 are EDA 2+ , and 80 are FA + . Then, among the A-site cations, the atomic percentage of MA + is 5%, the atomic percentages of cesium, rubidium and EDA 2+ are also each 5%, and the atomic percentage of FA + is 80%. And the above atomic percentages also reflect the proportion of the content of these types of A-site cations at the A-site, that is, the content proportion of FA + in the A-site cations is the largest.

[0075] Furthermore, the first type of A-site cations includes at least two kinds. Adding at least two kinds of the first type of A-site cations can achieve a wide bandgap of the perovskite material while improving the problem of A-site phase segregation. Specifically, to achieve a wide bandgap of the perovskite material, if one kind of the first type of A-site cation is used for adjustment, a larger amount of it is required to achieve the purpose of adjusting the bandgap, but this will make A-site phase segregation more likely to occur. When two or more kinds of the first type of A-site cations are introduced in this application, the amount of each kind of the first type of A-site cation is relatively reduced, A-site phase segregation is not likely to occur, and the characteristics of the perovskite material having a wide bandgap can be well adjusted.

[0076] Furthermore, the bandgap of the perovskite material is 1.65 eV to 1.8 eV. Exemplarily, the bandgap of the perovskite material is 1.65 eV, 1.68 eV, 1.70 eV, 1.72 eV, 1.75 eV, 1.78 eV, or 1.8 eV.

[0077] The perovskite material with the above bandgap belongs to the wide-bandgap perovskite material. Thus, the three-dimensional perovskite material provided by the embodiments of this application not only has good bulk phase stability and good material uniformity, but also has the characteristic of a wide bandgap, making it more suitable for combination applications with some narrow-bandgap materials. For example, it can be combined with silicon-based batteries to manufacture multi-junction stacked solar cells, providing efficient solar cells with industrial application prospects.

[0078] Furthermore, the atomic percentage of the second type of A-site cations in the A-site cations is less than or equal to 10%. Exemplarily, the atomic percentage of the second type of A-site cations in the A-site cations is 10%, 9%, 8%, 6%, 5%, 4%, or 3%. Controlling the atomic percentage of the A-site cations with a relatively large size, i.e., the second type of A-site cations, below 10% is beneficial to better control the perovskite material to maintain an effective three-dimensional structure and avoid or reduce the formation of two-dimensional perovskite structures.

[0079] In addition to optimizing and regulating the A-site cations, the embodiments of this application also optimize and regulate the X-site anions on this basis. The X-site anions include at least three different kinds of halogen anions and / or pseudohalogen anions, and one of the X-site anions is I - , and the other kinds of X-site anions include the first type of X-site anions with an ionic radius smaller than I - , the second type of X-site anions with an ionic radius larger than I - . The first type of X-site anions includes at least one kind, and the second type of X-site anions includes at least one kind; among the X-site anions, the atomic percentage of the first type of X-site anions is greater than the atomic percentage of the second type of X-site anions.

[0080] In the embodiments of the present application, the types, ionic radii, proportions, etc. of anions at the X site of the perovskite material are also synergistically controlled, which can further improve the stability degree of the perovskite material, improve the X-site phase segregation problem, and ensure the wide bandgap of the perovskite.

[0081] Among them, there are more than three kinds of halogen and / or pseudohalogen anions at the X site, which can further increase the entropy value of the perovskite material and help further enhance the bulk phase stability of the three-dimensional perovskite structure. On this basis, one of the X-site anions is I - , and at least one of the other X-site anions has an ionic radius smaller than I - , and one has an ionic radius larger than I - , thereby adjusting and reducing the influence brought by the differences in ionic diffusion coefficient, formation energy, etc. between other X-site anions and I - , and alleviating the X-site phase segregation problem.

[0082] Furthermore, among the X-site anions, the atomic percentage of I - is greater than or equal to 50%. Exemplarily, among the X-site anions, the atomic percentage of I - is 50%, 60%, 70%, 75%, 80%, 85%, 90% or 95%. In the present application, the X-site anions are mainly formamidinium cations with I - . Through the cooperation of other X-site anions with smaller and larger ionic radii and I - , it helps to broaden the bandgap while better realizing the comprehensive stability of the perovskite material.

[0083] It should be noted that one way in the related art to adjust the bandgap of the perovskite material to 1.65 eV - 1.8 eV is: introducing non-iodine halogen or pseudohalogen as the main component at the X-site anion, and at the same time supplementing with the first type of A-site cations with a size smaller than the formamidinium cation, but this is very likely to cause phase segregation or even phase separation. Taking the preparation of the perovskite layer by coating a cation solution on the lead iodide skeleton layer as an example, since the ionic diffusion coefficients of other halogens or pseudohalogens other than iodine ions and the formation energies of their reactions with the lead iodide skeleton layer are significantly different from the ionic diffusion coefficient of iodine ions and the formation energy of its reaction with the skeleton layer, when using this method to widen the bandgap, phase segregation and lattice defects (such as vacancy defects) will be formed in the perovskite layer, affecting the efficiency and stability of the preparation of perovskite devices.

[0084] The idea of adjusting the band gap in this application is mainly to use at least two types of first-class A-site cations at the A-site, supplemented by a small amount of other halogens and / or pseudohalogens that introduce non-iodine ions, so as to weaken the influence of introducing these types of X-site anions on phase segregation. Through the comprehensive regulation of the above aspects, the perovskite material of the embodiment of this application not only has a wide band gap but also can improve the comprehensive stability, so that the perovskite device using this perovskite material still has good performance after being placed for a long time.

[0085] Optionally, the first-class A-site cations include MA + , Cs + , K + , Ca 2+ , Zn 2+ , Na + or Rb + and at least two of them. Among them, MA + refers to methylammonium cation.

[0086] Optionally, the second-class A-site cations include DMA + , BA + , PA + , AA + , BMIM + , EA + or EDA 2+ and at least one of them. Among them, DMA + refers to dimethylammonium methylammonium cation, BA + refers to n-butylammonium cation, PA + refers to propylammonium cation, AA + refers to allylammonium cation, BMIM + refers to 1-butyl-3-methylimidazolium cation, EA + refers to ethylammonium ion, EDA 2+ refers to ethylenediamine divalent cation.

[0087] In the case of introducing MA + , it is easy to volatilize rapidly during the annealing crystallization process of making perovskite materials, resulting in crystallization defects; in the case of introducing alkali metal ions such as Cs + or Rb + , there are large differences in ion diffusion coefficient, formation energy, etc. between these alkali metal ions and FA + , so phase segregation is likely to occur. By introducing the second-class A-site cations, the above problems such as crystallization defects and phase segregation can be better improved, and they play a cooperative role with the first-class A-site cations.

[0088] Optionally, the B-site cations include Pb 2+ , Ga 2+ and Sn2+ at least one of

[0089] Optionally, the first type of X-site anion includes F - , Br - , Cl - at least one of

[0090] Optionally, the second type of X-site anion includes SCN - , OCN - , BF 4 - , TFSI - , CF 3 - , CF 3 CO 2 - , COO - or SO 3 H - at least one of

[0091] Preferably, the chemical formula of the perovskite material is (FA a1 DMA a2 MA a3 PA a4 Cs a5 Rb a6 )PbI 3 , a1:a2:a3:a4:a5:a6 = (50 - 90):(0.5 - 5):(3 - 22):(1 - 6):(1 - 16):(0.5 - 10).

[0092] Preferably, the chemical formula of the perovskite material is (FA a1 DMA a2 MA a3 PA a4 Cs a5 Rb a6 )Pb(I b1 Cl b2 Br b3 ), a1:a2:a3:a4:a5:a6 = (50 - 90):(0.5 - 5):(3 - 22):(1 - 6):(1 - 16):(0.5 - 10), b1:b2:b3 = (70 - 95):(0.5 - 8):(3 - 25).

[0093] Preferably, the chemical formula of the perovskite material is (FA a1 DMA a2 MA a3 PA a4 Cs a5 Rb a6 )Pb(I b1Cl b2 Br b3 OCN b4 SCN b5 ), a1:a2:a3:a4:a5:a6 = (50 - 90):(0.5 - 5):(3 - 22):(1 - 6):(1 - 16):(0.5 - 10), b1:b2:b3:b4:b5 = (70 - 90):(0.5 - 6):(2 - 20):(0.5 - 8):(0.5 - 8).

[0094] The above three-dimensional perovskite material can simultaneously meet the following requirements: having a wide bandgap to match the requirements of tandem cells of narrow bandgap materials (such as crystalline silicon bottom cells), good perovskite bulk phase stability and high material uniformity to meet the performance requirements of perovskite devices.

[0095] In a second aspect, the embodiment of the present application further provides a preparation method of the perovskite material in the first aspect above, including the following steps:

[0096] Coat a cation solution on the skeleton layer and anneal to obtain the perovskite material;

[0097] Wherein, the skeleton layer includes at least B-site cations and X-site anions, and the cation solution includes some or all of the A-site cations.

[0098] It can be understood that the skeleton layer includes at least B-site cations and X-site anions means that: the skeleton layer can be a skeleton layer composed of B-site cations and X-site anions, or there are also some A-site cations in the skeleton layer composed of B-site cations and X-site anions. For example, if the B-site cation is Pb 2+ and the X-site anion is I - , then the skeleton layer can be a PbI 2 skeleton layer, or it can be a PbI 2 skeleton layer doped with some types of A-site cations. In addition, the cation solution includes some or all of the A-site cation solutions means that: the cation solution can include all types of A-site cations, or only include some types of A-site cations, and the other part of the A-site cations are placed in the skeleton layer, so that all A-site cations can participate in the reaction with the skeleton layer.

[0099] The embodiment of the present application uses a two-step method to produce the perovskite material, which is suitable for preparing perovskite materials with requirements for maintaining the texture. That is to say, it can not only obtain perovskite materials with comprehensive stability characteristics, but also meet the production requirements of perovskite materials with a texture-preserving structure. For example: when applied to a solar cell with a textured structure, it can not only provide a perovskite light-absorbing layer with good comprehensive stability, improve the light utilization efficiency, but also meet the requirements of industrial production.

[0100] Furthermore, the surface of the skeleton layer has a suede structure.

[0101] Furthermore, the film thickness of the perovskite material is 500 nm to 2000 nm.

[0102] Furthermore, the A-site cations are divided into alkali metal cations and organic cations. Before the step of coating the cation solution on the skeleton layer, the preparation method of the perovskite material further includes the following steps:

[0103] Preparing the skeleton layer: Co-evaporating a material source containing alkali metal cations, a material source containing B-site cations, and a material source containing X-site anions by evaporation deposition to obtain the skeleton layer;

[0104] Preparing the cation solution: Dissolving the organic cations in a green organic solvent, and the green organic solvent includes at least one of ethanol and isopropanol.

[0105] It can be understood that according to the size of the ionic radius, the A-site cations include formamidinium cations, the first type of A-site cations with an ionic radius smaller than that of formamidinium cations, and the second type of A-site cations with an ionic radius larger than that of formamidinium cations. Classified according to the properties of organic or inorganic substances, the A-site cations include alkali metal cations and organic cations.

[0106] In order to increase the entropy value of the A-site cations in this application, different alkali metal cations and organic cations can be selected as the first type of A-site cations and the second type of A-site cations according to the requirements of the ionic radius. When preparing the perovskite material by a two-step method, the alkali metal cations are prepared into the skeleton layer by co-evaporation, and the cation solution only includes organic cations with good compatibility in the organic solvent, thereby ensuring that both the alkali metal cations and the organic cations can participate in the reaction for forming the perovskite material according to the preset dosage, and avoiding the problem that the alkali metal cations have poor solubility in the organic solvent and cannot participate in the reaction with a large dosage. In addition, since the alkali metal cations are co-evaporated into the skeleton layer, the dosage and distribution of the alkali metal cations in the skeleton layer can be flexibly adjusted according to the needs; since the organic cations have good compatibility in the organic solvent, their dosage can be flexibly adjusted according to the needs.

[0107] Furthermore, the above-mentioned organic solvent includes at least one of ethanol and isopropanol. The above-mentioned solvent is a green organic solvent, so that the preparation process of the embodiment of this application not only can meet the requirements of the suede shape retention of the perovskite material and is suitable for industrial production requirements, but also has the advantages of environmental friendliness.

[0108] Preferably, in the step of preparing the skeleton layer, PbI 2, CsBr, and RbBr are co-evaporated at an evaporation rate ratio of (8 - 12):(0.5 - 2.2):(0.1 - 1.2) to obtain a lead iodide framework layer containing alkali metal inorganic salts, and the thickness of the framework layer is 300 nm - 750 nm.

[0109] Preferably, in the step of preparing the cation solution, FAI, DMAI, MAI, MACl, and PACl are dissolved in isopropanol according to an atomic percentage of (70 - 90):(3 - 12):(8 - 12):(8 - 22):(3 - 12) to obtain a cation solution.

[0110] Preferably, in the step of coating the cation solution on the framework layer, the coating is carried out according to the atomic percentage of FA + :DMA + :MA + :PA + :Cs + :Rb + being (70 - 90):(3 - 6):(6 - 18):(2 - 6):(4 - 6):(2 - 5).

[0111] Ions of different types have different evaporation rates during high-temperature annealing, resulting in changes in content. Therefore, through the above preferred solutions, it is further ensured that the final perovskite light-absorbing layer can obtain better performance.

[0112] In a third aspect, the present application also provides a perovskite device, which includes the perovskite material as described in the first aspect, or the perovskite device includes the perovskite material prepared by the preparation method as described in the second aspect.

[0113] Optionally, the perovskite device includes at least one of a perovskite solar cell, a perovskite light-emitting diode, or a perovskite laser. Preferably, the perovskite device is a perovskite solar cell, and the perovskite solar cell includes a perovskite tandem solar cell or a perovskite single-junction solar cell.

[0114] In an optional implementation manner, the perovskite device is a perovskite tandem solar cell. Combining Figure 1As shown in the figure, the perovskite tandem solar cell includes: a bottom cell 1 with a planar or textured surface, an electron-hole recombination layer 2, a first transport layer 31, a perovskite light-absorbing layer 4, a second transport layer 32, and a transparent conductive layer 5 that are sequentially disposed on the surface of the bottom cell 1, a first electrode 61 in electrical contact with the transparent conductive layer 5, and a second electrode 62 in electrical contact with the bottom cell 1; wherein, one of the first transport layer 31 and the second transport layer 32 is an electron transport layer and the other is a hole transport layer, one of the first electrode 61 and the second electrode 62 is a positive electrode and the other is a negative electrode, and the perovskite light-absorbing layer 4 includes the perovskite material mentioned in the first aspect or the second aspect above.

[0115] The film layers of the perovskite tandem solar cell will be further explained below.

[0116] Among them, the bottom cell 1 includes at least one of a crystalline silicon bottom cell 1, a copper indium gallium selenide bottom cell 1, a perovskite narrow-bandgap bottom cell 1, or an organic bottom cell 1.

[0117] Among them, the material of the electron-hole recombination layer 2 includes at least one of IZO and ITO; the thickness of the electron-hole recombination layer 2 is 2 nm to 30 nm. The material of the hole transport layer includes nickel oxide; the thickness of the hole transport layer is 5 nm to 30 nm. The thickness of the perovskite light-absorbing layer 4 is 500 nm to 2000 nm. The material of the electron transport layer includes C 60 ; the thickness of the electron transport layer is 5 nm to 30 nm. The material of the transparent conductive layer 5 includes at least one of ITO, IZO, or IWO; the thickness of the transparent conductive layer 5 is 30 nm to 150 nm. The material of the electrode includes at least one of gold, silver, copper, or aluminum; the thickness of the electrode is 50 nm to 400 nm.

[0118] In addition to the above structure, the perovskite tandem solar cell may further include other functional film layers, including:

[0119] A hole modification layer 7, disposed between the hole transport layer and the perovskite light-absorbing layer 4, the material of the hole modification layer 7 is a single-molecule self-assembled material, and the single-molecule self-assembled material includes at least one of 2PACz, 4PACz, or MeO-2PACz; and / or,

[0120] A passivation layer 8, disposed between the perovskite light-absorbing layer 4 and the second transport layer 32, the material of the passivation layer 8 includes LiF or a two-dimensional perovskite material, and the thickness of the passivation layer 8 is 0.5 nm to 5 nm; and / or,

[0121] A buffer layer 9, disposed between the second transport layer 32 and the transparent conductive layer 5, and the thickness of the buffer layer 9 is 5 nm to 30 nm; and / or,

[0122] The antireflection layer 10 is disposed on the side of the transparent conductive layer 5 facing away from the second transport layer 32, and the thickness of the antireflection layer 10 is 80 nm to 150 nm.

[0123] Among them, 2PACz, 4PACz or MeO-2PACz are all derivatives of carbazole phosphonic acid (PACz).

[0124] In another alternative embodiment, the perovskite device is a perovskite single-junction solar cell, and the perovskite single-junction solar cell includes: a transparent conductive substrate with a planar or textured surface, a first transport layer, a perovskite light-absorbing layer, and a second transport layer sequentially disposed on the transparent conductive substrate, a first electrode in electrical contact with the second transport layer, and a second electrode in electrical contact with the transparent conductive substrate; wherein, one of the first transport layer and the second transport layer is an electron transport layer and the other is a hole transport layer, one of the first electrode and the second electrode is a positive electrode and the other is a negative electrode, and the perovskite light-absorbing layer includes the perovskite material mentioned in the first aspect or the second aspect above.

[0125] Fourthly, the embodiments of the present application provide a photovoltaic module, and the photovoltaic module includes a solar cell. The solar cell includes a perovskite light-absorbing layer, and the perovskite light-absorbing layer includes the perovskite material as described in the first aspect, or the perovskite light-absorbing layer includes the perovskite material prepared by the preparation method as described in the second aspect.

[0126] The following further describes the embodiments of the present application in combination with specific embodiments and test results.

[0127] Example 1

[0128] This embodiment provides a perovskite tandem solar cell, which is prepared by the following preparation method:

[0129] Provide an HJT crystalline silicon cell with a textured structure as the bottom cell;

[0130] Prepare an IZO layer with a thickness of 20 nm as an electron-hole recombination layer on the bottom cell;

[0131] Prepare a hole transport layer and a hole modification layer sequentially on the electron-hole recombination layer. The hole transport layer is a NiOx layer with a thickness of 20 nm, and the hole modification layer is a single-molecule self-assembled material 4PACz;

[0132] Prepare a perovskite light-absorbing layer on the hole modification layer:

[0133] Prepare a lead iodide skeleton layer: Use a vacuum thermal evaporation coater to co-evaporate PbI 2 , CsBr and RbBr materials at an evaporation rate ratio of 10:1:1 to obtain an alkali metal inorganic salt lead iodide skeleton layer, and the thickness of the skeleton layer is 550 nm;

[0134] Prepare a cationic solution: Dissolve FAI, DMAI, MAI, MACl, and PACl in isopropanol to obtain a cationic solution;

[0135] Coat the cationic solution on the skeleton layer and anneal it to obtain a perovskite light-absorbing layer with a thickness of 850 nm; among them, the A-site cations include FA with an atomic percentage of approximately 84:2:4:2:5:3 + , DMA + , MA + , PA + , Cs + , and Rb + , MA + , Cs + , and Rb + have smaller ionic radii than FA + , and DMA + , and PA + have larger ionic radii than FA + ; the X-site anions include I - , Br - , Cl - ;

[0136] Prepare a 1-nm-thick LiF as a passivation layer on the perovskite light-absorbing layer;

[0137] Prepare a 20-nm-thick C 60 on the passivation layer as an electron transport layer;

[0138] Prepare a 20-nm buffer layer on the electron transport layer;

[0139] Prepare a transparent conductive layer, an antireflection layer, and an electrode on the buffer layer in sequence; among them, the transparent conductive layer is a 100-nm-thick ITO layer, the antireflection layer has a thickness of 100 nm, and the electrode material is silver with a thickness of 200 nm.

[0140] Examples 2 to 4

[0141] The difference between this example and Example 1 lies in: the types and ratios of A-site cations, and the types and ratios of X-site cations are different. See Table 1 for details.

[0142] Comparative Example 1

[0143] This comparative example provides a perovskite tandem solar cell. The difference between this comparative example and Example 1 lies in: the type of A-site cation is different. The A-site cations in this comparative example only include formamidinium cations and the first type of A-site cations with ionic radii smaller than formamidinium cations, and do not include the second type of A-site cations with ionic radii larger than formamidinium cations. See Table 1 for details.

[0144] Comparative Example 2

[0145] This comparative example provides a perovskite tandem solar cell. The difference between this comparative example and Example 1 lies in that: the types of A-site cations are different. The A-site cations in this comparative example only include formamidinium cations and the second type of A-site cations with an ionic radius larger than that of formamidinium cations, and do not include the first type of A-site cations with an ionic radius smaller than that of formamidinium cations. See Table 1 for details.

[0146] Comparative Example 3

[0147] This comparative example provides a perovskite tandem solar cell. The difference between this comparative example and Example 1 lies in that: among the A-site cations, the atomic percentage of the first type of A-site cations is less than that of the second type of A-site cations. See Table 1 for details.

[0148] Comparative Examples 4 - 5

[0149] The difference between this comparative example and Example 1 lies in the different proportion of the dosage of FA + . See Table 1 for details.

[0150] Table 1 Perovskite materials of examples and comparative examples

[0151]

[0152]

[0153] Note: 1. " / " indicates the absence of this component;

[0154] 2. The atomic percentage refers to the atomic percentage of each component in the order listed in Table 1. Taking Example 1 as an example, the order of the A-site cations listed in Table 1 is FA + , MA + , Cs + , Rb + , DMA + , PA + , then the atomic percentage refers to the atomic percentage of FA + :MA + :Cs + :Rb + :DMA + :PA + is 84:4:5:3:2:2.

[0155] Performance test

[0156] For the perovskite tandem solar cells of the above-mentioned examples and comparative examples, performance tests such as open-circuit voltage, fill factor, and photoelectric conversion efficiency were carried out using a halm test and sorting device. The halm machine is a device that simulates sunlight, and is equipped with an electronic load, data acquisition and calculation devices, etc., for testing the electrical performance of photovoltaic devices (including solar cells). The calibrated light intensity of the tested solar cell was controlled to be 1000±5W / m 2 .

[0157] Stability test: After placing the perovskite tandem battery tested by the halm test and sorting device for 3000 hours, the photoelectric conversion efficiency was tested again, and the retention rate of the photoelectric conversion efficiency was calculated: (photoelectric conversion efficiency after 3000 hours / initial photoelectric conversion efficiency) × 100%.

[0158] The test results are shown in Table 2 below:

[0159] Table 2 Initial efficiency and 3000-hour stability test results of examples and comparative examples

[0160]

[0161] By comparing the experimental results of Examples 1 to 3 and Comparative Examples 1 to 3, it can be seen that the second type of A-site cation in the A-site cation does not contain an ionic radius larger than the formamidinium cation, or the A-site cation does not contain the first type of A-site cation with an ionic radius smaller than the formamidinium cation, or although the A-site cation includes both the first type of A-site cation and the second type of A-site cation, but when the atomic percentage of the second type of A-site cation is greater than that of the first type of A-site cation, the prepared perovskite light-absorbing layer fails to help improve the photoelectric conversion efficiency of the solar cell. It can be seen that simply increasing the entropy value by increasing the component types of the A-site cation is not sufficient to effectively improve the comprehensive stability of the perovskite material, and thus is not very helpful for improving the performance of the solar cell with a perovskite light-absorbing layer. Only by doing as in the examples of the present application, that is, increasing the entropy value by increasing the component types of the A-site cation and controlling the ionic radius and atomic percentage of each A-site cation, can the comprehensive stability of the perovskite material be more effectively ensured, ensuring that no obvious phase segregation occurs, and thus more effectively promoting the solar cell to improve the photoelectric conversion efficiency.

[0162] By further comparing Example 1 and Comparative Example 4, it can be seen that the solar cell of Example 1 has better photoelectric conversion efficiency. It can be seen that on the basis of improving the A-site cation, appropriately regulating the FA + ion content (not less than 50%) helps to further improve the comprehensive stability of the perovskite material and also helps to further promote the improvement of the photoelectric conversion efficiency of the solar cell. Because FA +The content is too low. To maintain the wide-bandgap perovskite required for tandem cells, it is necessary to increase the content of the first and second types of A-site cations, which leads to phase segregation and a poor tolerance factor, resulting in an unstable structure. However, FA + The content is too high. To maintain the wide-bandgap perovskite required for tandem cells, it is necessary to reduce the content of the first and second types of A-site cations and increase the content of Br - and Cl - in the X-site anions, etc., which leads to phase segregation and a poor tolerance factor, resulting in an unstable structure. By further comparing Example 1 and Example 2, it can be seen that the solar cell in Example 1 has better photoelectric conversion efficiency. It can be seen that when using more than two types of the first type of A-site cations, it is more helpful to improve the comprehensive stability of the perovskite material, and thus conducive to more effectively improving the relevant performance of the solar cell.

[0163] By further comparing Example 1 and Example 3, it can be seen that the solar cell in Example 1 has better photoelectric conversion efficiency. It can be seen that further controlling the atomic percentage of the second type of A-site cations within 10% is more helpful to improve the comprehensive stability of the perovskite material, and thus conducive to more effectively improving the relevant performance of the solar cell.

[0164] By further comparing Example 1 and Example 4, it can be seen that the solar cell in Example 4 has better photoelectric conversion efficiency. It can be seen that on the basis of improving the A-site cations, further optimizing the X-site anions by controlling their component types, ionic radii, and dosages helps to further improve the comprehensive stability of the perovskite material and also helps to further promote the improvement of the photoelectric conversion efficiency of the solar cell.

[0165] The technical solutions disclosed in the embodiments of the present application have been introduced in detail above. Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The descriptions of the above embodiments are only used to help understand the technical solutions and core invention points of the embodiments of the present application: At the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A perovskite material, characterized in that: The perovskite material has a three-dimensional structure, the general chemical formula of the perovskite material is ABX3, A is an A-position cation, B is a B-position cation, and X is an X-position anion; The A-site cations include at least five different types of cations, one of which is a formamidinium cation, and the other types of A-site cations include a first type of A-site cation whose ionic radius is smaller than that of the formamidinium cation and a second type of A-site cation whose ionic radius is larger than that of the formamidinium cation; among the A-site cations, the atomic percentage of the first type of A-site cations is greater than the atomic percentage of the second type of A-site cations, and among the A-site cations, the atomic percentage of the formamidinium cations is 50% to 90%.

2. The perovskite material according to claim 1, characterized in that The first type of A-site cations includes at least two types.

3. The perovskite material according to claim 2, characterized in that: The band gap of the perovskite material is 1.65 eV to 1.80 eV.

4. The perovskite material according to claim 1, characterized in that The atomic percentage of the second type of A-site cations in the A-site cations is less than or equal to 10%.

5. The perovskite material according to claim 1, characterized in that The X-position anions include at least three different types of halogen anions and / or pseudohalogen anions, wherein one of the X-position anions is - Other types of X-position anions include those with an ionic radius smaller than that of the - The first type of X-position anion, the ionic radius of which is larger than that of the I - The second type of X-site anions of the present invention comprises at least one type of X-site anions, and the second type of X-site anions comprises at least one type of X-site anions; among the X-site anions, the atomic percentage of the first type of X-site anions is greater than the atomic percentage of the second type of X-site anions.

6. The perovskite material according to claim 1, characterized in that The first type of A-site cations include MA + , Cs + , K + , Ca 2+ 、Zn 2+ 、Na + or Rb + At least two of; and / or, The second type of A-site cations include DMA + , B.A. + ,PA + AA + BMIM + ,EA + or EDA 2+ At least one of; and / or, The B-site cation includes Pb 2+ , Ga 2+ and Sn 2+ At least one of; and / or, The X-site anion includes I - , the ionic radius is smaller than the I - The first type of X-position anion, the ionic radius of which is larger than that of the I - The second type of X-site anion, wherein the first type of X-site anion includes F - Br - , Cl - At least one of the second X-site anions includes SCN - 、OCN - 、BF4 - TFSI - CF3 - CF3CO2 - 、COO - or SO3H - At least one of the X-position anions, the I - The atomic percentage is greater than or equal to 50%.

7. The perovskite material according to any one of claims 1 to 6, characterized in that: The chemical formula of the perovskite material is (FA a1 DMA a2 MA a3 PA a4 Cs a5 R a6 )PbI3, a1:a2:a3:a4:a5:a6=(50-90):(0.5-5):(3-22):(1-6):(1-16):(0.5-10); or, The chemical formula of the perovskite material is (FA a1 DMA a2 MA a3 PA a4 Cs a5 R a6 )Pb(I b1 Cl b2 Br b3 ), a1:a2:a3:a4:a5:a6=(50~90):(0.5~5):(3~22):(1~6):(1~16):(0.5~10), b1:b2:b3=(70~95):(0.5~8):(3~25); or, The chemical formula of the perovskite material is (FA a1 DMA a2 MA a3 PA a4 Cs a5 R a6 )Pb(I b1 Cl b2 Br b3 OCN b4 SCN b5 ), a1:a2:a3:a4:a5:a6=(50~90):(0.5~5):(3~22):(1~6):(1~16):(0. 5~10), b1:b2:b3:b4:b5=(70~90):(0.5~6):(2~20):(0.5~8):(0.5~8).

8. A method for preparing a perovskite material, characterized in that: The perovskite material comprises the perovskite material according to any one of claims 1 to 7, and the method for preparing the perovskite material comprises the following steps: coating a cationic solution on the skeleton layer and annealing to obtain the perovskite material; Wherein, the skeleton layer at least includes the B-site cations and the X-site anions, and the cationic solution includes part or all of the A-site cations.

9. The preparation method according to claim 8, characterized in that: The surface of the skeleton layer has a suede structure; and / or, The film thickness of the perovskite material is 500nm to 2000nm; and / or, The A-site cations are divided into alkali metal cations and organic cations. Before the step of coating the cation solution on the skeleton layer, the method for preparing the perovskite material further includes the following steps: Preparing the skeleton layer: using a vapor deposition method to co-evaporate a material source containing the alkali metal cation, a material source containing the B-site cation, and a material source containing the X-site anion to obtain the skeleton layer; The cationic solution is prepared by dissolving the organic cation in an organic solvent.

10. The preparation method according to claim 9, characterized in that: In the step of preparing the skeleton layer, PbI2, CsBr and RbBr are co-evaporated at an evaporation rate ratio of (8-12):(0.5-2.2):(0.1-1.2) to obtain a lead iodide skeleton layer containing an alkali metal inorganic salt, wherein the thickness of the skeleton layer is 300nm-750nm; and / or, In the step of preparing the cationic solution, FAI, DMAI, MAI, MACl and PACl are dissolved in isopropanol according to the atomic percentage of (70-90):(3-12):(8-12):(8-22):(3-12) to obtain the cationic solution; and / or, In the step of preparing the cationic solution, the organic solvent includes at least one of ethanol and isopropanol; and / or, In the step of coating the cationic solution on the skeleton layer, according to the FA in the A-position cation + :DMA + :MA + :PA + :Cs + :Rb + The coating is carried out in the atomic percentage of (70-90):(3-6):(6-18):(2-6):(4-6):(2-5).

11. A perovskite device, characterized in that: The perovskite device comprises the perovskite material according to any one of claims 1 to 7, or the perovskite device comprises the perovskite material prepared by the preparation method according to any one of claims 8 to 10.

12. The perovskite device according to claim 11, characterized in that The perovskite device includes at least one of a perovskite solar cell, a perovskite light emitting diode or a perovskite laser.

13. The perovskite device according to claim 12, characterized in that: The perovskite device is a perovskite tandem solar cell, which comprises: a bottom cell with a flat or velvety surface, an electron-hole recombination layer, a first transport layer, a perovskite light absorption layer, a second transport layer, a transparent conductive layer, a first electrode electrically in contact with the transparent conductive layer, and a second electrode electrically in contact with the bottom cell, wherein one of the first transport layer and the second transport layer is an electron transport layer and the other is a hole transport layer, one of the first electrode and the second electrode is a positive electrode and the other is a negative electrode, and the perovskite light absorption layer comprises the perovskite material; Alternatively, the perovskite device is a perovskite single-junction solar cell, which includes: a transparent conductive substrate with a flat or velvety surface, a first transmission layer, a perovskite light absorption layer, and a second transmission layer arranged in sequence on the transparent conductive substrate, a first electrode electrically contacting the second transmission layer, and a second electrode electrically contacting the transparent conductive substrate; wherein, one of the first transmission layer and the second transmission layer is an electron transmission layer, and the other is a hole transmission layer, one of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode, and the perovskite light absorption layer includes the perovskite material.

14. The perovskite device according to claim 13, characterized in that The perovskite device is the perovskite tandem solar cell, and the bottom cell includes at least one of a crystalline silicon bottom cell, a copper indium gallium selenide bottom cell, a perovskite narrow bandgap bottom cell or an organic bottom cell; and / or, The material of the electron-hole composite layer includes at least one of IZO and ITO; and / or, The thickness of the electron-hole composite layer is 2nm to 30nm; The material of the hole transport layer includes nickel oxide; and / or, The thickness of the hole transport layer is 5nm to 30nm; and / or, The thickness of the perovskite light absorbing layer is 500nm to 2000nm; and / or, The material of the electron transport layer includes C 60 and / or, The thickness of the electron transport layer is 5 nm to 30 nm; and / or, The material of the transparent conductive layer includes at least one of ITO, IZO or IWO; and / or, The thickness of the transparent conductive layer is 30nm to 150nm; and / or, The material of the electrode includes at least one of gold, silver, copper or aluminum; and / or, The thickness of the electrode is 50nm-400nm.

15. The perovskite device according to claim 13, characterized in that: The perovskite device is the perovskite tandem solar cell, and the perovskite tandem solar cell further comprises: A hole modification layer is provided between the hole transport layer and the perovskite light absorption layer, wherein the material of the hole modification layer is a single molecule self-assembly material, and the single molecule self-assembly material includes at least one of 2PACz, 4PACz or MeO-2PACz; and / or, A passivation layer is provided between the perovskite light absorption layer and the second transmission layer, the material of the passivation layer includes LiF or a two-dimensional perovskite material, and the thickness of the passivation layer is 0.5 nm to 5 nm; and / or, a buffer layer, disposed between the second transmission layer and the transparent conductive layer, wherein the thickness of the buffer layer is 5 nm to 30 nm; and / or, The anti-reflection layer is disposed on a side of the transparent conductive layer away from the second transmission layer, and the thickness of the anti-reflection layer is 80nm-150nm.

16. A photovoltaic module, characterized in that: The photovoltaic module includes a solar cell, the solar cell includes a perovskite light-absorbing layer, the perovskite light-absorbing layer includes the perovskite material according to any one of claims 1 to 7, or the perovskite light-absorbing layer includes the perovskite material prepared by the preparation method according to any one of claims 8 to 10.

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