Perovskite solar cell and preparation method and application thereof

Abstract

The invention provides a perovskite solar cell and a preparation method and application thereof. The perovskite solar cell comprises a first electrode layer, a hole transport layer, a perovskite layer, an electron transport layer and a second electrode layer which are arranged in sequence. A chelating passivation layer is arranged between the hole transport layer and the perovskite layer, and / or a chelating passivation layer is arranged between the perovskite layer and the electron transport layer; the material of the perovskite layer comprises ABX3, and a chelating agent in the chelating passivation layer is combined with A-site cations and B-site cations, so that the chelating agent and organic cations and metal cations of perovskite form strong supramolecular interaction, defects caused by cation volatilization are reduced, metal cations which are not coordinated at a grain boundary are passivated, and thus, the surface of the perovskite layer is protected. According to the perovskite solar cell, the defect state density of the perovskite layer and the non-radiative recombination of the device are reduced, so that the photo-generated load excitons of the perovskite solar cell in the working process are effectively separated, the charge transmission efficiency is improved, and the perovskite solar cell has excellent stability and photoelectric conversion performance.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, specifically relating to a perovskite solar cell, its preparation method, and its application. Background Technology

[0002] Solar cells are based on semiconductor materials, and their working principle is to utilize the photovoltaic reaction that occurs after the material absorbs light energy, thus achieving photoelectric conversion. Perovskite materials, as a type of semiconductor material with tunable bandgap, have seen significant development in the field of solar cells in recent years. Perovskite materials are a class of compounds with the structural formula ABX3, where the A-site is CH3NH3. + (MA + CH(NH2)2 + (FA + ), Cs + Etc., B is Pb 2+ The X-site is a halogen. The band gap of perovskite materials can be adjusted by changing the halogen composition at the X-site; when the X-site contains a certain proportion of Br and I, the band gap of the perovskite is 1.68-1.72 eV. Perovskite materials with this band gap are usually called wide-bandgap perovskites. Wide-bandgap perovskites have great potential as top cells in perovskite / crystalline silicon solar cells in the future.

[0003] However, wide-bandgap perovskites exhibit a larger on-voltage loss than iodine-based perovskites (ABI3), typically exceeding 0.4V, thus limiting further improvements in energy conversion efficiency. Furthermore, wide-bandgap perovskite solar cells are susceptible to phase separation during operation, ultimately leading to poor stability. Current research has demonstrated that these phenomena are caused by ion migration, which typically occurs at grain boundaries and due to defects on the crystal surface.

[0004] Currently, a common method in the industry to improve the performance of wide-bandgap perovskite solar cells is to add suitable additives to the perovskite precursor solution. For example, CN112542549A discloses a wide-bandgap perovskite solar cell, in which the preparation method of the wide-bandgap perovskite thin film includes: dissolving lead iodide, lead bromide, methylammonium iodide and methylammonium bromide in an ionic liquid methylammonium acetate at a molar ratio of 3:1:3:1 to prepare a wide-bandgap perovskite precursor solution, and then spin-coating the precursor solution onto ITO transparent conductive glass that has been deposited with electron transport materials and interface materials in air using a one-step heating spin-coating method. After annealing, a perovskite thin film is formed. The precursor solution contains strong hydrogen bonding, which slows down the growth process of perovskite crystals, thereby obtaining a wide-bandgap perovskite thin film with fewer defects and better crystal orientation. CN116940189A discloses a method for preparing a wide-bandgap perovskite thin film, comprising the following steps: dissolving oleamine iodine in a mixed solvent of DMF and DMSO to form an oleamine iodine solution; adding the oleamine iodine solution to a solution containing CsI, FAPbI3, and MAPbBr3 to obtain a perovskite precursor solution; spin-coating the perovskite precursor solution and treating it with ethyl acetate as an antisolvent, followed by annealing at 95-100℃ to crystallize and obtain a perovskite thin film; then depositing a PEAI solution on the perovskite thin film for 2D passivation and annealing to obtain a passivation layer on the surface of the perovskite thin film, thereby obtaining a high-quality wide-bandgap perovskite thin film.

[0005] The additives used in existing technologies can interact with the precursor solution to regulate crystal growth and reduce defects, or they can passivate defects, thereby improving the quality of perovskite films and the performance of the cells to some extent. However, the improvement effect of existing additives on cell performance is insufficient, and there is still considerable room for improvement in the photoelectric conversion efficiency of wide-bandgap perovskite cells. Therefore, developing higher-performance wide-bandgap perovskite cells is an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a perovskite solar cell, its preparation method, and its application. By designing a specific chelating passivation layer, the charge transport efficiency of the perovskite solar cell is improved, resulting in excellent photoelectric conversion efficiency and stability.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a perovskite solar cell, the perovskite solar cell comprising a first electrode layer, a hole transport layer, a perovskite layer, an electron transport layer and a second electrode layer disposed sequentially; a chelating passivation layer is disposed between the hole transport layer and the perovskite layer, and / or a chelating passivation layer is disposed between the perovskite layer and the electron transport layer.

[0009] The material of the perovskite layer includes ABX3, wherein A is selected from any one or a combination of at least two of metal cations and organic cations, B is selected from any one or a combination of at least two of metal cations and organic cations, and X is selected from one or a combination of at least two anions.

[0010] The chelating passivation layer includes a chelating agent that binds to the A-site cations and B-site cations of the perovskite layer.

[0011] In the perovskite solar cell provided by this invention, a chelating passivation layer is provided on one side of the perovskite layer. The chelating agent therein can form hydrogen bonds, cation-π interactions, etc., with the A-site cations (e.g., organic cations) in the perovskite; moreover, the chelating agent can interact with the B-site cations (e.g., metal cations Pb) in the perovskite. 2+ Sn 2+ The chelating agent described in this invention can form coordination bonds with A-site and B-site cations in the perovskite layer, respectively, greatly reducing defects caused by cation volatilization during the annealing step of battery fabrication and / or during battery operation. It can also effectively passivate uncoordinated metal cations (e.g., Pb) at grain boundaries. 2+ This reduces the defect state density of the perovskite layer, improves the quality of the perovskite layer, reduces non-radiative recombination in the battery device, and enables the photogenerated excitons in the perovskite solar cell to be effectively separated during operation, thereby improving charge transport efficiency and resulting in higher photoelectric conversion efficiency and excellent stability.

[0012] Preferably, the chelating agent has the structure shown in Formula I:

[0013]

[0014] In Formula I, R1 is selected from any one of hydrogen, substituted or unsubstituted C1-C10 (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10) straight-chain or branched alkyl, substituted or unsubstituted C3-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, C10) cycloalkyl, substituted or unsubstituted C6-C30 (e.g., C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, etc.) aryl, and substituted or unsubstituted C3-C30 (e.g., C3, C4, C5, C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, etc.) heteroaryl.

[0015] In Formula I, R2 is selected from any one of substituted or unsubstituted C6-C30 (e.g., C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, etc.) aryl groups and substituted or unsubstituted C3-C30 (e.g., C3, C4, C5, C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, etc.) heteroaryl groups.

[0016] The substituents described in R1 and R2 are each independently selected from at least one of halogens, unsubstituted or halogenated C1-C10 (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10) straight-chain or branched alkyl groups, unsubstituted or halogenated C1-C10 (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10) alkoxy groups, C3-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, C10) cycloalkyl groups, C6-C20 (e.g., C6, C9, C10, C12, C14, C16, C18, etc.) aryl groups, and C3-C20 (e.g., C3, C4, C5, C6, C9, C10, C12, C14, C16, C18, etc.) heteroaryl groups.

[0017] As a preferred embodiment of the present invention, the chelating agent in the chelating passivation layer has a structure as shown in Formula I. The N atom of the pyrrole group in the chelating agent can form a hydrogen bond with the organic cation in the perovskite, while the π electrons can form a cation-π interaction with the organic cation. Furthermore, the N atom in the chelating agent reacts with the metal ions (Pb) in the perovskite. 2+ Sn 2 + The chelating agent, as shown in Formula I, forms a coordination bond with both organic and metal cations in the perovskite layer, thereby significantly reducing defects caused by cation volatilization during the annealing step of battery fabrication and / or during battery operation. Furthermore, it effectively passivates uncoordinated metal cations (Pb) at grain boundaries. 2+ This reduces the defect state density of the perovskite layer, improves the quality of the perovskite layer, reduces non-radiative recombination in the battery device, and enables the photogenerated excitons in the perovskite solar cell to be effectively separated during operation, thereby improving charge transport efficiency and resulting in higher photoelectric conversion efficiency and excellent stability.

[0018] The following are further preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the purpose and beneficial effects of the present invention can be better achieved and realized.

[0019] In this invention, the halogen can be fluorine, chlorine, bromine, or iodine. The same descriptions used below have the same meaning.

[0020] In this invention, the C1-C10 straight-chain or branched alkyl groups can be straight-chain or branched alkyl groups of C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10, and exemplary include but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2-methylbutyl, n-pentyl, isopentyl, neopentyl, n-hexyl, neohexyl, 2-ethylhexyl, n-octyl, n-heptyl, n-nonyl, n-decyl, etc.

[0021] In this invention, the C1-C10 alkoxy groups can all be straight-chain or branched alkoxy groups of C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10, that is, monovalent groups obtained by connecting the aforementioned straight-chain or branched alkyl groups with O.

[0022] In this invention, the C3-C10 cycloalkyl groups can all be C3, C4, C5, C6, C7, C8, C9, or C10 cycloalkyl groups, including monocycloalkyl or polycycloalkyl groups, and exemplary, including but not limited to: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, etc.

[0023] In this invention, the C6-C30 aryl groups can all be aryl groups of C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, or C28, etc., and the C6-C20 aryl groups can all be aryl groups of C6, C9, C10, C12, C14, C16, C18, etc.; including monocyclic aryl groups and fused-ring aryl groups, exemplarily including but not limited to: phenyl, biphenyl, terphenyl, tetraphenyl, naphthyl, anthracene, phenanthrene, fluorene and their derivatives (9,9-dimethylfluorenel, 9,9-diphenylfluorenel, spirodifluorenel, etc.). It should be noted that monocyclic aryl groups and fused-ring aryl groups connected by single bonds also fall within the scope of aryl groups, such as phenylnaphthyl, naphthylphenyl, binaphthyl, etc.

[0024] In this invention, the C3-C30 heteroaryl groups can all be heteroaryl groups of C3, C4, C5, C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, or C28, etc., and the C3-C20 heteroaryl groups can all be heteroaryl groups of C3, C4, C5, C6, C9, C10, C12, C14, C16, C18, etc. The heteroatoms in the heteroaryl groups can be N, O, S, P, B, Si, etc. Heteroaryl groups include monocyclic heteroaryl groups or fused-ring heteroaryl groups, including but not limited to: pyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, furanyl, thiopheneyl, pyrroleyl, quinolinyl, isoquinolinyl, quinoxalinyl, quinazolinyl, benzofuranyl, benzothiopheneyl, indolyl, dibenzofuranyl, dibenzothiopheneyl, carbazoleyl and its derivatives (N-phenylcarbazoleyl, etc.).

[0025] In this invention, the halogenated C1-C10 (C1, C2, C3, C4, C5, C6, C7, C8, C9, C10) straight-chain or branched alkyl group is a monovalent group obtained by replacing at least one hydrogen atom in the C1-C10 straight-chain or branched alkyl group with a halogen.

[0026] In this invention, the halogenated C1-C10 (C1, C2, C3, C4, C5, C6, C7, C8, C9, C10) alkoxy group is a monovalent group obtained by replacing at least one hydrogen atom in the C1-C10 alkoxy group with a halogen.

[0027] Preferably, R1 is selected from any one of substituted or unsubstituted C6-C20 aryl groups, and more preferably any one of the following groups: phenyl, biphenyl, terphenyl, naphthyl.

[0028] Preferably, R2 is selected from any one of substituted or unsubstituted C6-C30 aryl groups, and more preferably any one of the following substituted or unsubstituted groups:

[0029]

[0030] In this context, *- represents the linking site of a functional group.

[0031] Preferably, the chelating agent is selected from any one or a combination of at least two of the following compounds:

[0032]

[0033] Where Ph represents phenyl.

[0034] In a preferred embodiment, the preparation method of the chelating agent with the structure shown in Formula I includes the following steps:

[0035] The halopyrrole undergoes a coupling reaction with an aromatic boric acid compound with the structure shown in Formula II to give an intermediate with the structure shown in Formula III, as shown in the following reaction formula:

[0036]

[0037] The intermediate reacts with an aldehyde compound of Formula IV to yield a chelating agent of Formula I, as shown in the following reaction formula:

[0038]

[0039] Wherein, R1 and R2 have the same limiting range as in Formula I; Hal is selected from any of the halogens, for example, it can be F, Cl, Br or I, and Cl, Br or I are more preferred.

[0040] Preferably, the coupling reaction is carried out in the presence of a palladium catalyst.

[0041] Preferably, the palladium catalyst comprises bis(triphenylphosphine)palladium acetate (Pd(OAc)2(PPh3)2) or tetra(triphenylphosphine)palladium (Pd(PPh3)4).

[0042] Preferably, the coupling reaction is carried out in the presence of a solvent.

[0043] Preferably, the solvent used in the coupling reaction includes any one or a combination of at least two of dioxane, tetrahydrofuran, toluene, and water.

[0044] Preferably, the reaction of the intermediate with the aldehyde compound is carried out in the presence of a catalyst and an oxidant.

[0045] Preferably, the catalyst comprises pyridine p-toluenesulfonate.

[0046] Preferably, the oxidant comprises 2,3-dichloro-5,6-dicyano-1,4-benzoquinone.

[0047] Preferably, the reaction between the intermediate and the aldehyde compound is carried out in the presence of a solvent.

[0048] Preferably, the solvent used for the reaction of the intermediate with the aldehyde compound includes alkane solvents and / or haloalkane solvents, including, but not limited to, any one or a combination of at least two of dichloroethane, dichloromethane, and chloroform.

[0049] It should be noted that the chelating agent with the structure shown in Formula I is not limited to the preparation method and raw materials described in this invention. Those skilled in the art can also select other methods or routes to obtain the chelating agent with the structure shown in Formula I.

[0050] In this invention, the chelating passivation layer formed by the chelating agent with the structure shown in Formula I can be a continuous or discontinuous thin film structure, preferably a continuous thin film structure.

[0051] Preferably, the material of the perovskite layer includes ABX3, wherein A is selected from any one or a combination of at least two of metal cations and organic cations, B is selected from any one or a combination of at least two of metal cations, and X is selected from any one or a combination of at least two of halide anions and chalcogenide anions.

[0052] More preferably, the material of the perovskite layer includes ABX3, wherein A is selected from CH3NH3. + CH(NH2)2 + Cs + 、Rb + B is any one or at least two of the following; B is selected from Sn. 2+ and / or Pb 2+ X is selected from I - ,Br - Cl - Any one or at least two of them.

[0053] Preferably, A is selected from CH3NH3. + and / or CH(NH2)2 + .

[0054] Preferably, B is Pb. 2+ and optional Sn 2+ .

[0055] As a preferred embodiment of the present invention, the material of the perovskite layer includes ABX3, wherein A is CH3NH3. + (MA + ) and / or CH(NH2)2 + (FA + B can be Pb 2+ It can also be Pb 2+ With Sn 2+ The combination of [unclear - likely referring to a specific combination or process]. The chelating agent in the chelating passivation layer can react with the N atom of the pyrrole group and the MA [unclear - likely referring to a specific type of chelating agent]. + FA + Hydrogen bonds are formed, and π electrons can interact with MA. + FA + The chelating agent forms a cation-π bond. Further, the chelating agent can react with Pb via the N atom of the pyrrole group. 2+ Coordinate bonds are formed, and π electrons can interact with Pb. 2+ The formation of cation-π occurs. Therefore, the organic cation MA in the perovskite layer... + and / or FA +and metal cation Pb 2+ Both can form strong supramolecular interactions with chelating agents, meaning that the chelating agents simultaneously bind two types of cations in the perovskite, thereby effectively suppressing defects caused by cation volatilization during the annealing step of the battery fabrication process and / or during battery operation, and passivating uncoordinated Pb at grain boundaries. 2+ This reduces the defect state density of the perovskite layer and the non-radiative recombination of the battery device, enabling the effective separation of photogenerated excitons during the operation of the perovskite solar cell, improving charge transport efficiency, and significantly enhancing photoelectric performance.

[0056] Preferably, the thickness of the perovskite layer is 200-900 nm, for example, it can be 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm or 850 nm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0057] In this invention, there are no special restrictions on the material used as the first electrode layer. Conventional electrode materials that can be used in the photovoltaic field and solar cells are applicable to this invention, as are any conductive layer or tunneling layer materials with carrier transport capabilities.

[0058] Preferably, the material of the first electrode layer includes any one or a combination of at least two of ITO, FTO, IZO, and AZO.

[0059] Preferably, the material of the first electrode layer includes ITO and / or FTO.

[0060] Preferably, a substrate is further provided on the side of the first electrode layer away from the hole transport layer, and the substrate and the first electrode layer constitute a conductive substrate layer.

[0061] Preferably, the substrate is made of glass or a polymer.

[0062] Preferably, the polymer comprises any one or a combination of at least two of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyimide (PI).

[0063] Preferably, the thickness of the conductive substrate layer is 20-150nm, for example, it can be 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 105nm, 110nm, 115nm, 120nm, 125nm, 130nm, 135nm, 140nm or 145nm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0064] In this invention, there are no special restrictions on the material used as the hole transport layer; conventional hole transport materials that can be used in the photovoltaic field and solar cells are all applicable to this invention.

[0065] Preferably, the material of the hole transport layer includes any one or a combination of at least two of nickel oxide, copper phthalocyanine, cuprous thiocyanate, poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine) (PTAA), poly(3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS), and poly(3-hexylthiophene).

[0066] Preferably, the thickness of the hole transport layer is 20-200nm, for example, it can be 30nm, 50nm, 70nm, 90nm, 100nm, 120nm, 150nm, 170nm or 190nm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0067] In this invention, there are no special restrictions on the materials used as the electron transport layer; conventional electron transport materials that can be used in the photovoltaic field and solar cells are all applicable to this invention.

[0068] Preferably, the material of the electron transport layer includes 2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline (BCP), C 60 Any one or a combination of at least two of the following: fullerene derivatives, tin dioxide, and zinc oxide.

[0069] Preferably, the fullerene derivative (PCBM) comprises [6,6]-phenyl-C 61 Methyl butyrate and / or [6,6]-phenyl-C 71 -Methyl butyrate.

[0070] Preferably, the thickness of the electron transport layer is 10-50 nm, for example, it can be 12 nm, 15 nm, 18 nm, 20 nm, 22 nm, 25 nm, 28 nm, 30 nm, 32 nm, 35 nm, 38 nm, 40 nm, 45 nm, 45 nm or 48 nm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0071] For example, the electron transport layer includes a first electron transport layer and a second electron transport layer; the second electron transport layer is located on the side close to the second electrode layer.

[0072] Preferably, the material of the first electron transport layer is C. 60 ; and / or, the material of the second electron transport layer is BCP.

[0073] Preferably, the thickness of the first electron transport layer is 10-40 nm, for example, it can be 12 nm, 15 nm, 18 nm, 20 nm, 22 nm, 25 nm, 28 nm, 30 nm, 32 nm, 35 nm or 38 nm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0074] Preferably, the thickness of the second electron transport layer is 1-15nm, for example, it can be 2nm, 5nm, 8nm, 10nm, 12nm or 14nm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0075] In this invention, there are no special restrictions on the material used as the second electrode layer. Conventional electrode materials that can be used in the photovoltaic field and solar cells are applicable to this invention, as are any conductive layer or tunneling layer materials with carrier transport capabilities.

[0076] In this invention, the second electrode layer is also called the "back electrode layer", and is preferably a metal electrode layer.

[0077] Preferably, the material of the second electrode layer includes any one or a combination of at least two of Al, Au, and Ag.

[0078] Preferably, the thickness of the second electrode layer is 50-150nm, for example, it can be 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm or 140nm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0079] In a second aspect, the present invention provides a method for preparing a perovskite solar cell as described in the first aspect, the method comprising method I or method II;

[0080] The method I includes: sequentially depositing a hole transport layer, a perovskite layer, a chelation passivation layer, an electron transport layer, and a second electrode layer on a first electrode layer to obtain the perovskite solar cell;

[0081] Method II includes: sequentially depositing an electron transport layer, a perovskite layer, a chelating passivation layer, a hole transport layer, and a first electrode layer on a second electrode layer to obtain the perovskite solar cell.

[0082] Preferably, the method for preparing the chelated passivation layer includes:

[0083] A chelating agent solution is provided, the chelating agent solution comprising a combination of a chelating agent with the structure shown in Formula I and an organic solvent;

[0084] The chelating agent solution is coated onto the perovskite layer to obtain the chelated passivation layer.

[0085] Preferably, the organic solvent in the chelating agent solution includes any one or a combination of at least two of unsubstituted or halogenated alkane solvents and unsubstituted or halogenated aromatic solvents.

[0086] Preferably, the organic solvent in the chelating agent solution includes any one or a combination of at least two of n-hexane, n-heptane, petroleum ether, and cyclohexane.

[0087] Preferably, the concentration of the chelating agent in the chelating agent solution is 0.2-5 mg / mL, for example, it can be 0.3 mg / mL, 0.5 mg / mL, 0.8 mg / mL, 1 mg / mL, 1.2 mg / mL, 1.5 mg / mL, 1.8 mg / mL, 2 mg / mL, 2.2 mg / mL, 2.5 mg / mL, 2.8 mg / mL, 3 mg / mL, 3.2 mg / mL, 3.5 mg / mL, 3.8 mg / mL, 4 mg / mL, 4.2 mg / mL, 4.5 mg / mL, or 4.8 mg / mL, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0088] Preferably, the method for coating the chelating agent solution onto the perovskite layer includes spin coating, blade coating, or slot coating.

[0089] As a preferred technical solution of the present invention, the chelating agent solution is coated onto the perovskite layer to form a film, thereby obtaining a chelated passivation layer. By adjusting the concentration of the chelating agent solution and / or the coating process parameters (such as the spin coating speed, time, etc.), the concentration of the chelating agent in the perovskite solar cell can be adjusted, thereby obtaining different passivation effects.

[0090] It should be noted that, regardless of whether it is Method I or Method II, the chelated passivation layer can be prepared using the above methods.

[0091] Preferably, the method for preparing the perovskite layer includes:

[0092] A perovskite precursor solution is provided, the perovskite precursor solution comprising a combination of ABX3 and a solvent; wherein A is selected from CH3NH3. + CH(NH2)2 + Cs + 、Rb + B is any one or at least two of the following; B is selected from Sn. 2+ and / or Pb 2+ X is selected from I - ,Br - Cl - Any one or at least two of them;

[0093] The perovskite precursor solution is coated onto a hole transport layer or an electron transport layer and then annealed to obtain the perovskite layer.

[0094] Preferably, the solvent in the perovskite precursor solution includes any one or a combination of at least two of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and γ-butyrolactone (GBL).

[0095] Preferably, the method for preparing the perovskite precursor solution includes: mixing ABX3 with a solvent to obtain the perovskite precursor solution.

[0096] Preferably, the mixed material further includes additives, including but not limited to: any one or a combination of at least two of methylamine chloride (MACl), ammonium dimethylformate (DMAFo), and aspartic acid.

[0097] Preferably, the concentration of ABX3 in the perovskite precursor solution is 0.5-5 mol / L, for example, it can be 0.6 mol / L, 0.8 mol / L, 1 mol / L, 1.2 mol / L, 1.5 mol / L, 1.8 mol / L, 2 mol / L, 2.2 mol / L, 2.5 mol / L, 2.8 mol / L, 3 mol / L, 3.2 mol / L, 3.5 mol / L, 3.8 mol / L, 4 mol / L, or 4.5 mol / L, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0098] Preferably, the method of coating the perovskite precursor solution onto the hole transport layer (method I) or the electron transport layer (method II) includes spin coating, blade coating, or slot coating.

[0099] Preferably, the coating process further includes a vacuum solvent removal step.

[0100] Preferably, in the step of vacuum solvent removal, the sample coated with the perovskite precursor solution is transferred to a vacuum chamber and the solvent is removed by rapid vacuuming, with the vacuum level reduced to 10 Pa within at least 20 seconds.

[0101] Preferably, the annealing temperature is 80-150℃, for example, it can be 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃ or 145℃, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0102] Preferably, the annealing time is 10-60 min, for example, it can be 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min or 55 min, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0103] It should be noted that the perovskite layer can be prepared by the above methods in both Method I and Method II. The difference is that Method I involves coating the electron transport layer with a perovskite precursor solution and then annealing it, while Method II involves coating the hole transport layer with a perovskite precursor solution and then annealing it.

[0104] In this invention, the preparation method of the electron transport layer and hole transport layer is not specifically limited. Methods known in the art for forming electron transport layers and hole transport layers, such as coating (spin coating, blade coating, slot coating), vapor deposition, etc., are all applicable to this invention.

[0105] Preferably, the method for preparing the hole transport layer includes: coating a hole transport material solution onto a first electrode layer (method I) or a chelated passivation layer (method II), and obtaining the hole transport layer after annealing.

[0106] Preferably, in method I, the method for preparing the electron transport layer includes: depositing an electron transport material on a chelated passivation layer to obtain the electron transport layer.

[0107] Preferably, in method I, the second electrode layer is prepared by vapor deposition.

[0108] Thirdly, this invention provides an application of the perovskite solar cell described in the first aspect in photovoltaic modules, perovskite tandem solar cells, or photodetectors. It should be noted that the perovskite solar cell of this invention can be either a conventional perovskite cell structure or an inverted structure; when applied to a perovskite tandem solar cell, the top cell on the light-receiving surface can be the perovskite solar cell of this invention, and the bottom cell on the back of the top cell can be a crystalline silicon solar cell, a silicon-germanium solar cell, a perovskite solar cell, or other thin-film solar cells, etc.

[0109] Fourthly, the present invention provides a tandem solar cell, the tandem solar cell comprising a top cell located on the light-receiving surface and a bottom cell located on the back side of the top cell, the top cell comprising a perovskite solar cell as described in the first aspect, and the bottom cell comprising a crystalline silicon solar cell or a thin-film solar cell.

[0110] Compared with the prior art, the present invention has the following beneficial effects:

[0111] The perovskite solar cell provided by this invention comprises a chelating passivation layer containing a specific chelating agent on one side of the perovskite layer. The chelating agent can form strong supramolecular interactions with organic cations and metal cations in the perovskite layer, respectively, which greatly reduces defects caused by cation volatilization during the annealing step of the cell fabrication process and / or during cell operation. It can also effectively passivate uncoordinated metal cations at grain boundaries, thereby reducing the defect state density of the perovskite layer, improving the quality of the perovskite layer, reducing nonradiative recombination of the cell device, and enabling effective separation of photogenerated excitons during the operation of the perovskite solar cell. This improves charge transport efficiency and significantly enhances open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency. The cell efficiency is ≥20%, and it still has a high conversion efficiency after 500 hours of continuous operation, exhibiting both excellent stability and photoelectric conversion performance. Attached Figure Description

[0112] Figure 1 This is a schematic diagram of the structure of the perovskite solar cell provided in Example 1;

[0113] Among them, 10-conductive substrate layer, 20-hole transport layer, 30-perovskite layer, 40-chelate passivation layer, 50-electron transport layer, 60-back electrode layer.

[0114] Figure 2 The chelating agents A1 and Pb used in Example 1 2+ A diagram illustrating coordination;

[0115] Figure 3 The chelating agents A1 and Pb used in Example 1 2+ Another schematic diagram of coordination;

[0116] Figure 4 The X-ray photoelectron spectra of the perovskite solar cells of Example 1 and Comparative Example 1 are shown in comparison. Detailed Implementation

[0117] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0118] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not limited to those elements and may also include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0119] In this invention, features specified as "first" and "second" may explicitly or implicitly include one or more of these features, used to distinguish and describe features, without any order or emphasis. In the description of this invention, unless otherwise stated, "multiple" means two or more.

[0120] In the following specific embodiments of the present invention, all raw materials used are commercially available materials.

[0121] Preparation Example 1

[0122] Chelating agent A1, molecular structure is (Ph represents phenyl), the preparation method is as follows:

[0123] (1)

[0124] 2-Chloroprene (5 mmol), 2,4,6-triphenylphenylboronic acid (5.5 mmol), tetrakis(triphenylphosphine)palladium Pd(PPh3)4 (0.3 mmol), potassium carbonate (35 mmol), tetrahydrofuran (120 mL), and purified water (25 mL) were added to the reaction flask. The reaction was carried out at 65 °C under a nitrogen atmosphere for 24 h. After cooling to room temperature, the reactants were extracted with dichloromethane. The organic phase was washed three times with water, and then the water in the organic phase was removed with anhydrous magnesium sulfate. The product was separated by column chromatography, and finally the solvent was removed by rotary evaporation to obtain intermediate A1-1.

[0125] (2)

[0126] Intermediate A1-1 (2.1 mmol), benzaldehyde (1 mmol), pyridine p-toluenesulfonate (0.9 mmol), and dichloroethane (10 mL) were added to a reaction flask. The reaction system was sealed and reacted at 85 °C for 24 h, during which the solution turned deep purple. After cooling the reaction system to room temperature, the solid was filtered and washed with dichloromethane until the solution changed from red to colorless. The dissolved solid was removed by rotary evaporation to obtain a pink solid. The solid was then dissolved in 150 mL of anhydrous dichloromethane, and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (1.2 mmol) was added. The reaction was carried out at room temperature under a nitrogen atmosphere for 3 h. The reaction was then terminated by adding 10 mL of triethylamine. The reaction system was then subjected to negative pressure to remove the solvent. The remaining solid was dissolved in n-hexane, filtered, and washed with toluene. The solvent was then removed under negative pressure, and the solid was dissolved in a minimal amount of n-hexane. The mixture was allowed to stand at -20 °C for 1 h, during which the solubility of the product decreased and it precipitated. The precipitate was obtained by filtration, yielding the chelating agent A1.

[0127] Preparation Example 2

[0128] Chelating agent A2, molecular structure is The only difference between its preparation method and that of Preparation Example 1 is that 2,4,6-triphenylphenylboronic acid in step (1) is replaced with an equimolar amount of 2,4-diphenylphenylboronic acid. Other raw materials, amounts, process steps and parameters are the same as those in Preparation Example 1.

[0129] Preparation Example 3

[0130] Chelating agent A3, molecular structure is The preparation method differs from that of Preparation Example 1 only in that 2,4,6-triphenylphenylboronic acid in step (1) is replaced with an equimolar amount of 2-phenylphenylboronic acid. All other raw materials, amounts, process steps and parameters are the same as those in Preparation Example 1.

[0131] Example 1

[0132] A schematic diagram of a perovskite solar cell is shown below. Figure 1 As shown, the perovskite solar cell includes a conductive substrate layer 10 (ITO), a hole transport layer 20, a perovskite layer 30, a chelating passivation layer 40, an electron transport layer 50, and a back electrode layer 60, which are stacked sequentially. The fabrication method of the perovskite solar cell is as follows:

[0133] (1) Cleaning the conductive substrate: The ITO conductive glass was ultrasonically cleaned with glass cleaning solution, deionized water, ethanol and isopropanol, dried at 200°C, dried with nitrogen gas, and then cleaned with ultraviolet ozone for 15 minutes to obtain the cleaned ITO conductive glass as the conductive substrate.

[0134] (2) Preparation of hole transport layer on ITO layer of conductive substrate: 60 μL of nickel oxide dispersion (concentration of 20 mg / mL, solvent of water) was dropped onto the cleaned ITO layer and spin-coated using a spin coater at a speed of 2000 rpm for 30 s; then it was placed on a heating stage for annealing at a temperature of 150 °C for 30 min to obtain a hole transport layer with a thickness of about 20 nm.

[0135] (3) Preparation of a perovskite layer on the hole transport layer: CsI, FAI (formamidinium iodide), PbI2, and PbBr2 were mixed in a molar ratio of 2:8:4:6 to prepare a solution with a concentration of 1.2M. The solvent was a DMF and DMSO solution with a volume ratio of 4:1. The solution was stirred for 2 hours to ensure complete dissolution. The resulting clear solution contained FAI was obtained by filtration. 0.8 Cs 0.2 Pb(I 0.6 Br 0.4)3 Perovskite precursor solution. Take 100 μL of perovskite precursor solution and drop it onto the surface of the hole transport layer. Spin coat it using a spin coater at a speed of 4000 rpm for 32 s. At the 24th s, add 100 μL of chlorobenzene as an antisolvent. Anneal the solution at 100℃ for 10 min to form a perovskite layer with a thickness of 520 nm.

[0136] (4) Preparation of chelating passivation layer on perovskite layer: Chelating agent A1 is dissolved in n-hexane to obtain chelating agent solution with a concentration of 2 mg / mL; the chelating agent solution is spin-coated onto the surface of perovskite layer at a speed of 2000 rpm for 20 s without heating, and left to stand at room temperature for 10 min to obtain chelating passivation layer.

[0137] (5) Preparation of an electron transport layer on the chelated passivation layer: A 25 nm C layer was deposited by vacuum evaporation. 60 8 nm 2,9-dimethyl-4,7-biphenyl-1,10-o-diazaphenanthroline (BCP) was used as the electron transport layer, and the evaporation rate was controlled at around 0.1 nm / s;

[0138] (6) Fabrication of back electrode on electron transport layer: 100 nm Ag is deposited as back electrode by vacuum evaporation to obtain the perovskite solar cell.

[0139] To demonstrate the interaction between chelating agent A1 and metal cation Pb in this embodiment... 2+ The coordination effect of chelating agent A1 and Pb was determined using Gaussian calculations. 2+ A diagram illustrating coordination, with the calculated level being B3LYP / def2tzvp, and the calculation results are as follows. Figure 2 and Figure 3 As shown, for a more intuitive understanding, all hydrogen atoms have been omitted, and all unlabeled atoms are carbon atoms; Figure 2 This indicates that the nitrogen atom in the two pyrrole groups is related to Pb. 2+ The coordination mode, Figure 3 It's the same optimized configuration, just viewed from a different angle, to better represent Pb. 2+ Due to the interaction of π electrons, both benzene rings are oriented towards Pb. 2+ .

[0140] Example 2

[0141] A perovskite solar cell differs from Example 1 only in that the material of the chelating passivation layer is chelating agent A2, that is, chelating agent A2 is used in the chelating agent solution in step (4); the structure, other materials and preparation method of the cell are the same as those of Example 1.

[0142] Example 3

[0143] A perovskite solar cell differs from Example 1 only in that the material of the chelating passivation layer is chelating agent A3, that is, chelating agent A3 is used in the chelating agent solution in step (4); the structure, other materials and preparation method of the cell are the same as those of Example 1.

[0144] Example 4

[0145] A perovskite solar cell differs from Example 1 only in that the concentration of chelating agent A1 in the chelating agent solution in step (4) is 0.5 mg / mL, and the solvent is n-hexane; the structure, materials and preparation method of the cell are the same as those in Example 1.

[0146] Example 5

[0147] A perovskite solar cell differs from Example 1 only in that the concentration of chelating agent A1 in the chelating agent solution in step (4) is 0.1 mg / mL, and the solvent is n-hexane; the structure, materials and other preparation methods of the cell are the same as those in Example 1.

[0148] Example 6

[0149] A perovskite solar cell differs from Example 1 only in that the concentration of chelating agent A1 in the chelating agent solution in step (4) is 5 mg / mL, and the solvent is n-hexane; the structure, materials and other preparation methods of the cell are the same as those in Example 1.

[0150] Example 7

[0151] A perovskite solar cell differs from Example 1 only in that the concentration of chelating agent A1 in the chelating agent solution in step (4) is 8 mg / mL, and the solvent is n-hexane; the structure, materials and other preparation methods of the cell are the same as those in Example 1.

[0152] Example 8

[0153] A perovskite solar cell differs from Example 1 only in that the concentration of chelating agent A1 in the chelating agent solution in step (4) is 0.05 mg / mL, and the solvent is n-hexane; the structure, materials and other preparation methods of the cell are the same as those in Example 1.

[0154] Comparative Example 1

[0155] A perovskite solar cell differs from Example 1 only in that it does not have a chelating passivation layer 40. That is, in the preparation method of the perovskite solar cell, step (4) is not performed, and step (5) is performed directly on the perovskite layer obtained in step (3) to prepare the electron transport layer. The other structures, materials and preparation methods of the cell are the same as those in Example 1.

[0156] The performance of the perovskite solar cells provided in Examples 1-8 and Comparative Example 1 was tested. The specific methods included: measurement using a solar energy simulation testing system. The light source of the solar energy simulation testing system was tested under a G2V Pico LED solar spectrum simulator at a solar intensity (AM 1.5G: 100mW / cm²). 2 Measurements were performed under the following conditions. A continuously varying voltage (-0.5V to 1.2V) was applied across the perovskite solar cell under test, and the output current of the perovskite solar cell was measured (using a Keithley 2400 tester). The product of the two measurements yielded the JV test curve, which showed the photoelectric conversion efficiency of the perovskite solar cell under different conditions.

[0157] (1) Open circuit voltage (Voc): The maximum voltage applied across the perovskite solar cell after irradiation by the solar simulation test system is the open circuit voltage (Voc);

[0158] (2) Short-circuit current (Jsc): The current when the potential difference between the positive and negative electrodes of a perovskite solar cell is 0.

[0159] (3) Fill factor (FF): FF = (I max ×V max ) / (Jsc×Voc)×100, where, I max and V max These are the current and voltage values ​​of a perovskite solar cell at its maximum power point;

[0160] (4) Photoelectric conversion efficiency (PCE): PCE=(Jsc×Voc×FF) / P in ×100%; where P in The incident power of the solar energy simulation test system;

[0161] (5) Stability: The battery was placed under a solar spectrum simulator with an intensity of AM 1.5G: 100mW / cm². 2 After working continuously for 500 hours in a nitrogen atmosphere, its PCE was tested.

[0162] The test data is shown in Table 1:

[0163] Table 1

[0164]

[0165] According to the performance data in Table 1, the present invention provides a chelating passivation layer containing a specific chelating agent on one side of the perovskite layer. This layer forms a strong supramolecular interaction with the organic and metal cations in the perovskite layer, which can reduce the defect state density of the perovskite layer, improve the quality of the perovskite layer, and comprehensively improve the open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency of the perovskite solar cell. Specifically, the open-circuit voltage of the perovskite solar cells in Examples 1-6 is 1.26-1.28V, and the short-circuit current is 19.76-19.98mA / cm. 2 The fill factor was 79.2-80.9%, the conversion efficiency was 19.8-20.7%, and the conversion efficiency after 500 hours of continuous operation was 18.7-20.3%. Compared with Comparative Example 1 without a chelating passivation layer, it showed significantly improved photoelectric performance, battery efficiency, and stability. Furthermore, the different concentrations of the chelating agent solution in Examples 1 and 4-8 resulted in different concentrations of chelates on the perovskite layer, leading to different passivation effects. Under the process conditions of Examples 1 and 4-8, the battery prepared with an additive concentration of 2 mg / mL had the highest efficiency, 20.7%. In Example 7, the higher chelating agent concentration, while improving the passivation effect, actually led to a rapid decrease in short-circuit current, and the final device efficiency was not significantly improved compared to Comparative Example 1. In Example 8, the lower chelating agent concentration resulted in insignificant passivation effect, and the final performance was not significantly different from the comparative example. Therefore, the preferred concentration of the chelating agent is 0.1-5 mg / mL.

[0166] Furthermore, the perovskite solar cells were characterized using X-ray photoelectron spectroscopy (XPS). The X-ray photoelectron spectra of the perovskite solar cells in Example 1 and Comparative Example 1 are shown in the figure below. Figure 4 As shown, from Figure 4 XPS spectra show that, in Comparative Example 1, no chelating agent was added, and there was a significant Pb content. 0 The signal was absent in the XPS spectrum of Example 1; the addition of the chelating agent in Example 1 can inhibit Pb by forming a supramolecular chelate with Pb. 0 The generation of these states reduces the defect state density and improves battery efficiency.

[0167] The applicant declares that this invention illustrates the perovskite solar cell, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above process steps, meaning that this invention does not necessarily rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials used in this invention, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A perovskite solar cell, characterized in that, The perovskite solar cell comprises a first electrode layer, a hole transport layer, a perovskite layer, an electron transport layer, and a second electrode layer arranged sequentially. A chelating passivation layer is provided between the hole transport layer and the perovskite layer, and / or a chelating passivation layer is provided between the perovskite layer and the electron transport layer; The material of the perovskite layer includes ABX3, wherein A is selected from any one or a combination of at least two metal cations and organic cations; B is selected from any one or a combination of at least two metal cations and organic cations; and X is selected from one anion or a combination of at least two anions. The chelating passivation layer includes a chelating agent that binds to the A-site cations and B-site cations of the perovskite layer.

2. The perovskite solar cell according to claim 1, characterized in that, The chelating agent has the structure shown in Formula I: R1 is selected from any one of hydrogen, substituted or unsubstituted C1-C10 straight-chain or branched alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl. R2 is selected from any one of substituted or unsubstituted C6-C30 aryl groups and substituted or unsubstituted C3-C30 heteroaryl groups; The substituents described in R1 and R2 are each independently selected from at least one of halogen, unsubstituted or halogenated C1-C10 straight-chain or branched alkyl, unsubstituted or halogenated C1-C10 alkoxy, C3-C10 cycloalkyl, C6-C20 aryl, and C3-C20 heteroaryl.

3. The perovskite solar cell according to claim 2, characterized in that, R1 is selected from any one of substituted or unsubstituted C6-C20 aryl groups; Preferably, R2 is selected from any one of substituted or unsubstituted C6-C30 aryl groups, and more preferably any one of the following substituted or unsubstituted groups: in, The linking site of the representative group.

4. The perovskite solar cell according to any one of claims 1-3, characterized in that, The chelating agent is selected from any one or a combination of at least two of the following compounds:

5. The perovskite solar cell according to claim 1, characterized in that, The material of the perovskite layer includes ABX3, wherein A is selected from CH3NH3. + CH(NH2)2 + Cs + 、Rb + B is any one or at least two of the following; B is selected from Sn. 2+ and / or Pb 2+ X is selected from I - ,Br - Cl - Any one or at least two of them; Preferably, the thickness of the perovskite layer is 200-900 nm.

6. The perovskite solar cell according to claim 1, characterized in that, The material of the first electrode layer includes ITO and / or FTO; Preferably, a substrate is further provided on the side of the first electrode layer opposite to the hole transport layer; Preferably, the substrate is made of glass or a polymer; Preferably, the material of the hole transport layer includes any one or a combination of at least two of nickel oxide, copper phthalocyanine, cuprous thiocyanate, poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine), poly(3,4-ethylenedioxythiophene:polystyrene sulfonate), and poly(3-hexylthiophene). Preferably, the thickness of the hole transport layer is 20-200 nm; Preferably, the material of the electron transport layer includes 2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline, C 60 Any one or a combination of at least two of the following: fullerene derivatives, tin dioxide, and zinc oxide; Preferably, the thickness of the electron transport layer is 10-50 nm; Preferably, the material of the second electrode layer includes any one or a combination of at least two of Al, Au, Ag, and Cu; Preferably, the thickness of the second electrode layer is 50-150 nm.

7. A method for preparing a perovskite solar cell according to any one of claims 1-6, characterized in that, The preparation method includes method I or method II; The method I includes: sequentially depositing a hole transport layer, a perovskite layer, a chelation passivation layer, an electron transport layer, and a second electrode layer on a first electrode layer to obtain the perovskite solar cell; Method II includes: sequentially depositing an electron transport layer, a perovskite layer, a chelating passivation layer, a hole transport layer, and a first electrode layer on a second electrode layer to obtain the perovskite solar cell.

8. The preparation method according to claim 7, characterized in that, The method for preparing the chelating passivation layer includes: A chelating agent solution is provided, the chelating agent solution comprising a combination of a chelating agent with the structure shown in Formula I and an organic solvent; The chelating agent solution is coated onto the perovskite layer to obtain the chelated passivation layer; Preferably, the organic solvent in the chelating agent solution includes any one or a combination of at least two of n-hexane, n-heptane, petroleum ether, and cyclohexane; Preferably, the concentration of the chelating agent in the chelating agent solution is 0.2-5 mg / mL.

9. The preparation method according to claim 7, characterized in that, The method for preparing the perovskite layer includes: A perovskite precursor solution is provided, the perovskite precursor solution comprising a combination of ABX3 and a solvent; wherein A is selected from CH3NH3. + CH(NH2)2 + Cs + 、Rb + B is any one or at least two of the following; B is selected from Sn. 2+ and / or Pb 2+ X is selected from I - ,Br - Cl - Any one or at least two of them; The perovskite precursor solution is coated onto a hole transport layer or an electron transport layer and then annealed to obtain the perovskite layer. Preferably, the annealing temperature is 80-150℃; Preferably, the annealing time is 10-60 minutes.

10. A tandem solar cell, characterized in that, The tandem solar cell includes a top cell located on the light-receiving surface and a bottom cell located on the back of the top cell. The top cell includes a perovskite solar cell as described in any one of claims 1-6, and the bottom cell includes a crystalline silicon solar cell or a thin-film solar cell.

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