Solar cell and method of manufacturing the same, electric device, and power generation device

Abstract

The application provides a solar cell and a preparation method therefor, an electricity consuming device and a power generation device. The solar cell comprises, from bottom to top, a first conductive electrode, a passivation layer, a light absorption layer, an electron transport layer and a second conductive electrode, wherein the passivation layer comprises a passivator represented by formula I. The solar cell provided by the application has excellent photoelectric conversion efficiency and stability.

Description

Technical Field

[0001] This application relates to the field of solar cell device technology, specifically to a solar cell and its manufacturing method, electrical device, and power generation device. Background Technology

[0002] With the large-scale development and utilization of non-renewable energy sources such as coal and oil, their reserves can no longer meet the needs of various industries, including agriculture and manufacturing. Therefore, renewable energy is gradually becoming one of the alternative energy sources to non-renewable energy sources to promote social and industrial development. Among these, solar cells are widely used due to their green and environmentally friendly characteristics, as well as their ability to generate electricity when exposed to sunlight.

[0003] In solar cells, a separate material is required as a hole transport layer. However, this fabrication method is complex and time-consuming, hindering the commercial mass production of solar cells. Furthermore, commonly used hole transport layer materials are expensive and have poor thermal stability, significantly reducing cell performance over extended periods. Developing a high-performance hole transport layer-free cell is an effective solution to these problems, but compared to fully-structured cells (containing a hole transport layer), it still suffers from insufficient charge transport capacity and low on-state voltage, affecting the cell's photoelectric conversion efficiency. Therefore, there is an urgent need to provide a hole transport layer-free solar cell with good photoelectric conversion efficiency and stability. Summary of the Invention

[0004] This application is made in view of the above-mentioned issues, and its purpose is to provide a solar cell without a hole transport layer, which has excellent photoelectric conversion efficiency and stability.

[0005] A first aspect of this application provides a solar cell including a passivation layer comprising a passivating agent of Formula I.

[0006]

[0007] Where A is selected from S or P;

[0008] R1, R2, and R3 are each independently selected from hydrogen and C1-C4 alkyl groups; R3 is present when A is P; R3 is absent when A is S.

[0009] R4 is selected from one or more of C6-C10 arylene, C6-C10 heteroarylene, and C1-C6 alkylene;

[0010] R5 is selected from oxyacid groups or oxyacid salt groups;

[0011] X- is a negatively charged ion.

[0012] In any embodiment, the solar cell includes a first conductive electrode, a passivation layer, a light-absorbing layer, an electron transport layer, and a second conductive electrode stacked sequentially from bottom to top.

[0013] The thioonium or phosphonium ions in the passivating agent are connected to oxyacid groups or oxyacid salt groups through R4, which helps to build an electric field between the first conductive electrode and the light-absorbing layer of the solar cell, promotes hole extraction and transport, and can also passivate defects on the surface of the perovskite light-absorbing layer, so that the solar cell can achieve both good photoelectric conversion efficiency and stability.

[0014] In any embodiment, the oxyacid group includes one or more of sulfonic acid group, phosphonic acid group, carboxylic acid group, boric acid group and hypophosphonic acid group; the oxyacid salt group includes one or more of alkali metal salts of sulfonic acid group, phosphonic acid group, carboxylic acid group, boric acid group and hypophosphonic acid group.

[0015] In any embodiment, the alkali metal salt includes one or more of sodium salt, potassium salt, rubidium salt, and cesium base.

[0016] In any embodiment, R5 is selected from sulfonic acid group, phosphonic acid group, carboxylic acid group, boric acid group, sodium phosphonate group, and cesium phosphonate group.

[0017] The oxyacid groups or oxyacid salt groups help increase the dipole moment of the passivating agent molecules, forming a built-in electric field between the light-absorbing layer and the first conductive electrode, promoting hole extraction and transport, and improving the photoelectric conversion efficiency of the solar cell.

[0018] In any implementation, R4 is selected from... Or C2-C4 alkylene,

[0019] The linking groups help improve the interaction between the passivator and the light-absorbing layer, allowing the passivator to function effectively, improving the overall structural integrity of the perovskite material in the light-absorbing layer, reducing non-radiative charge recombination at the interface of the light-absorbing layer, and improving the stability of the solar cell.

[0020] In any embodiment, R1, R2, and R3 are all selected from hydrogen or methyl.

[0021] In any implementation, X - Selected from halide ions or pseudohalogen ions.

[0022] In any embodiment, the halide ion includes F - Cl-, Br - One or more of I-; the pseudohalogen includes CN - SCN-, BF4 - PF6 - One or more of the following.

[0023] In any embodiment, the passivating agent is selected from any one of the following compounds:

[0024]

[0025] The passivating agent has a strong molecular dipole moment, which can form a strong built-in electric field between the light-absorbing layer and the first conductive electrode, promoting hole extraction and transport, acting as a hole transport layer, and improving the photoelectric conversion efficiency of the solar cell. At the same time, the sulfonium or phosphonium ions contained in the passivating agent are beneficial for passivating defects in perovskite materials and improving the stability of the solar cell.

[0026] In any embodiment, the passivation layer thickness is 0.1 nm to 20 nm.

[0027] An appropriate passivation layer thickness can effectively reduce the probability of electrons and holes recombinizing before they are effectively separated, improve hole transport efficiency, reduce degradation of the light-absorbing layer material, and improve the stability and photoelectric conversion efficiency of solar cells.

[0028] In any embodiment, the absolute value of the energy difference between the valence band top of the light-absorbing layer and the work function of the first conductive electrode does not exceed 0.5 eV. The smaller the energy difference between the valence band top of the light-absorbing layer and the work function of the first conductive electrode, the closer they are, which is more conducive to the efficiency of hole transport and extraction, reduces non-radiative recombination at the interface, and improves the stability and photoelectric conversion efficiency of the solar cell.

[0029] In any embodiment, the light-absorbing layer comprises a perovskite compound, which includes at least one of ABX3 and / or A2CDX6, wherein A, B, C, and D are all inorganic, organic, or mixed organic-inorganic cations, and A is a monovalent cation, including Cs. + CH3NH 3+ NH2CH=NH 2+ At least one of them; B is a divalent cation, including Pb 2+ Sn 2+ At least one of them, Pb 2+ or Sn 2+ C can be Ag + D can be Bi 3+ Sb 3+ In 3+ At least one of the following; X is an inorganic, organic, or mixed organic-inorganic anion, X including Br - I - At least one of them;

[0030] The first conductive electrode includes at least one of fluorine-doped tin oxide, indium tin oxide, aluminum-doped zinc oxide, boron-doped indium zinc oxide, and indium-doped zinc oxide.

[0031] In any embodiment, a barrier layer is disposed between the electron transport layer and the second conductive electrode, and the barrier layer satisfies at least one of the following:

[0032] (1) The conduction band bottom of the blocking layer is lower than the conduction band bottom of the light-absorbing layer, or the valence band top of the blocking layer is higher than the valence band top of the light-absorbing layer;

[0033] (2) The thickness of the barrier layer is 0.5nm-20nm;

[0034] (3) The barrier layer comprises one or more of 2,9-dimethyl-4,7-biphenyl-1,10-o-diazaphenanthroline, SnO2, ZnO and cerium oxide.

[0035] When the barrier layer between the electron transport layer and the second conductive electrode meets the aforementioned conditions, it facilitates the transmission of electrons from the light-absorbing layer to the second conductive electrode and helps to prevent the back diffusion of holes, reduce the non-radiative recombination of electrons and holes, and improve the photoelectric conversion efficiency of the solar cell.

[0036] In any embodiment, the first conductive electrode includes a conductive substrate, and the second conductive electrode includes a metal electrode.

[0037] A second aspect of this application provides a method for preparing a solar cell, comprising:

[0038] Provide a first conductive electrode;

[0039] A passivation layer is prepared on one side of the first conductive electrode;

[0040] A light-absorbing layer is prepared on the side of the passivation layer away from the first conductive electrode;

[0041] An electron transport layer is prepared on the side of the light-absorbing layer away from the passivation layer;

[0042] A second conductive electrode is fabricated on the side of the electron transport layer away from the light-absorbing layer;

[0043] The passivation layer includes the passivating agent shown in Formula I.

[0044]

[0045] Where A is selected from S or P;

[0046] R1, R2, and R3 are each independently selected from hydrogen and C1-C4 alkyl groups; R3 is present when A is P; R3 is absent when A is S.

[0047] R4 is selected from one or more of C6-C10 arylene, C6-C10 heteroarylene, and C1-C6 alkylene; R5 is selected from oxyacid groups or oxyacid salt groups.

[0048] X - It is a monovalent anion.

[0049] The method reduces the preparation of the hole transport layer, shortens the process flow, and lowers the production cost of solar cells.

[0050] In any embodiment, the passivation layer is prepared by a method comprising the following steps:

[0051] The passivating agent shown in Formula I is dissolved in water or an organic solvent to obtain a passivating material. The passivating material is then coated onto one side of the first conductive electrode to obtain a passivation layer.

[0052] The manufacturing process is mature and controllable, which is beneficial to the stability of solar cell production quality.

[0053] In any embodiment, the concentration of the passivating agent in the passivating material is 0.0001 mmol / mL to 0.1 mmol / mL, which is beneficial for the passivating material to be coated into a passivation layer of suitable thickness.

[0054] In any embodiment, the passivation layer and the light-absorbing layer are prepared by a method comprising the following steps:

[0055] The passivating agent shown in Formula I is dissolved in a light-absorbing layer active material precursor solution to obtain an in-situ passivating material. The in-situ passivating material is then coated on one side of the first conductive electrode to obtain a passivation layer coated on one side of the first conductive electrode and a light-absorbing layer located on the side of the passivation layer away from the first conductive electrode.

[0056] The method facilitates the one-step preparation of the light-absorbing layer and the passivation layer through in-situ passivation, reducing the number of process steps.

[0057] In any embodiment, the light-absorbing layer active material precursor solution includes lead halide, and in the in-situ passivation material, the molar ratio of the passivating agent represented by Formula I to the lead halide is 0.1%-10%.

[0058] Adding passivating agents to the precursor solution of the light-absorbing active material can effectively reduce defects in the perovskite material, achieving in-situ passivation and improving the stability of the solar cell. Simultaneously, the passivating agent promotes hole extraction and transport, acting as a hole transport layer and improving the photoelectric conversion efficiency of the solar cell.

[0059] A third aspect of this application also provides an electrical device comprising a solar cell of the first aspect of this application and a solar cell prepared by the preparation method of the second aspect.

[0060] A fourth aspect of this application also provides a power generation device comprising a solar cell of the first aspect of this application and a solar cell prepared by the preparation method of the second aspect.

[0061] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0062] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0063] Figure 1 This is a schematic diagram of the structure of a solar cell according to one embodiment of this application.

[0064] Explanation of reference numerals in the attached figures: 1: Solar cell; 10: First conductive electrode; 111: Passivation layer; 112: Light-absorbing layer; 113: Electron transport layer; 12: Second conductive electrode. Detailed Implementation

[0065] Hereinafter, embodiments of the solar cell, power-consuming device, and power-generating device of this application will be described in detail with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0066] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0067] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0068] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0069] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, optionally sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0070] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0071] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0072] Perovskite solar cells have attracted widespread attention due to their excellent photoelectric properties, such as tunable bandgap, high light absorption coefficient, long carrier lifetime and diffusion length, high defect tolerance, and low-cost low-temperature liquid-phase preparation method. However, the efficiency and stability of perovskite solar cells remain important issues for their commercial application.

[0073] In current solar cells, a separate material is required as a hole transport layer. However, this fabrication method is complex and time-consuming, hindering the commercial mass production of solar cells. The commonly used hole transport layer material is poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT:PSS), which is not only expensive but also an acidic solution with poor thermal stability, significantly reducing cell performance over long periods. Developing a high-performance hole transport layer-free cell is an effective solution to these problems. It simplifies the perovskite cell fabrication process, reduces costs, and avoids side reactions at the perovskite interface, promoting long-term stable operation. In perovskite cells with a hole transport layer-free structure, band bending occurs at the interface near the transparent electrode, preventing electrons from recombinating with holes in the transparent electrode and improving photoelectric conversion efficiency to some extent. However, compared to full-structure cells (containing a hole transport layer), insufficient charge transport capacity and low on-state voltage still exist, affecting the cell's photoelectric conversion efficiency.

[0074] [Perovskite Solar Cells]

[0075] Based on this, such as Figure 1 As shown, a first aspect of this application provides a solar cell 1, comprising a first conductive electrode 10, a passivation layer 111, a light-absorbing layer 112, an electron transport layer 113, and a second conductive electrode 12 stacked sequentially from bottom to top. The passivation layer comprises a passivating agent as shown in Formula I.

[0076]

[0077] Where A is selected from S or P;

[0078] R1, R2, and R3 are each independently selected from hydrogen and C1-C4 alkyl groups; R3 is present when A is P; R3 is absent when A is S.

[0079] R4 is selected from one or more of C6-C10 arylene, C6-C10 heteroarylene, and C1-C6 alkylene;

[0080] R5 is selected from oxyacid groups or oxyacid salt groups;

[0081] X- is a negatively charged ion.

[0082] In this article, chemical bonds This indicates whether the key exists or not. When When it is absent, the R3 group is not present.

[0083] In this paper, the term "C1-C4 alkyl" refers to a straight-chain or branched saturated hydrocarbon group containing 1 to 4 carbon atoms.

[0084] In this paper, the term "C6-C10 arylene" refers to the group formed by removing two hydrogen atoms from an aromatic hydrocarbon consisting of 6 to 10 carbon atoms, which can be a single ring or a fused ring.

[0085] In this document, the term "hybrid aryl" refers to a group formed by removing two hydrogen atoms from an aromatic hydrocarbon consisting of 5 to 12 atoms, which may be a single ring or a fused ring, and which contains at least one cyclic heteroatom. The heteroatom may be N, O, or S.

[0086] In this paper, the term "C1-C6 alkylene" refers to a straight-chain or branched hydrocarbon group with 1 to 6 carbon atoms. "Alkylene" indicates that the group is a bridging unit connecting two other atoms or groups, rather than a complete molecule.

[0087] In this article, the term "oxyacid group" refers to an acidic group containing an oxygen atom, which can release a proton (H+) and exhibit acidity. Oxyacid groups typically contain a central atom (such as sulfur, phosphorus, carbon, boron, etc.) bonded to one or more oxygen atoms, and sometimes also contain one or more hydroxyl groups (-OH).

[0088] In this paper, the term "oxyacid salt group" refers to the anion formed by the loss of one or more protons (H+) by an oxyacid group, which then combines with a cation to form a salt.

[0089] Without being bound by any theory, the sulfonium or phosphonium ions contained in the passivating agent carry a positive charge and can interact with the negatively charged sites in the perovskite material, passivating the surface defects of the perovskite material and improving the photoelectric conversion efficiency of the solar cell. Moreover, sulfonium or phosphonium ions have high stability and are less likely to undergo deprotonation reactions that can cause the degradation of the perovskite material compared to ammonium ions, which is beneficial to improving the stability of the solar cell.

[0090] The oxyacid groups at the ends of the passivator can remove hydrogen ions to form negatively charged anions, while the terminal groups contain positively charged thionium or phosphonium ions. This allows the entire passivator molecule to form a built-in electric field at the interface between the perovskite light-absorbing layer and the first conductive electrode (e.g., a conductive substrate). When the terminal group of the passivator molecule is an oxyacid salt group, it can increase the binding ability of the terminal group to the metal oxide conductive electrode. On the other hand, the oxyacid salt group can remove alkali metal ions to form negatively charged anions, which helps to increase the molecular dipole moment and form a built-in electric field at the interface (the direction of the built-in electric field is from positive charge to negative charge, i.e., from the perovskite light-absorbing layer to the first conductive electrode). This promotes hole extraction and transport, improves the photoelectric conversion efficiency of the solar cell, and the built-in electric field may also help reduce the defect density at the interface, improve the chemical and thermal stability of the material, and improve the stability of the solar cell.

[0091] The arylene and heteroarylene groups in the linking group R4 of the passivator have a strong conjugation effect, which enables the passivator to form a strong interaction with the light-absorbing layer. This is beneficial for the passivator to be firmly adsorbed on the surface of the light-absorbing layer. The C1-C6 alkylene groups can increase the contact area between the passivator and the surface of the light-absorbing layer through their chain length and flexibility. This is beneficial for the passivator to be evenly distributed on the surface of the light-absorbing layer, giving full play to the role of the passivator, improving the overall structural integrity of the perovskite material in the light-absorbing layer, reducing non-radiative charge recombination at the interface of the light-absorbing layer, and improving the photoelectric conversion efficiency and stability of the solar cell.

[0092] By placing a passivation layer containing the aforementioned passivating agent between the light-absorbing layer and the first conductive electrode, not only can the built-in electric field of the molecular dipole promote the transport and extraction of holes, thus acting as a hole transport layer, but it can also passivate the defects on the surface of the perovskite light-absorbing layer, enabling the solar cell to achieve both excellent photoelectric conversion efficiency and stability.

[0093] In some embodiments, the oxyacid group includes one or more of sulfonic acid group, phosphonic acid group, carboxylic acid group, boric acid group and hypophosphonic acid group.

[0094] In this paper, the term "sulfonic acid group" refers to the -SO3H group.

[0095] In this article, the term "phosphonic acid group" refers to the -PO(OH)2 group.

[0096] In this article, the term "carboxylic acid group" refers to the -COOH group.

[0097] In this article, the term "boronic acid group" refers to the -B(OH)2 group.

[0098] In this article, the term "phosphonic acid group" refers to the -PH(OH) group.

[0099] The oxyacid groups can remove hydrogen ions to form negatively charged anions, while the terminal groups of the passivator molecule contain positively charged sulfonium and phosphonium ions. Therefore, the entire passivator molecule is charged and can form a built-in electric field at the interface between the perovskite light-absorbing layer and the first conductive electrode, which promotes hole extraction and transport and is beneficial to improving the photoelectric conversion efficiency of the solar cell.

[0100] In some embodiments, the oxyacid salt group includes one or more alkali metal salts of sulfonic acid, phosphonic acid, carboxylic acid, boric acid, and hypophosphonic acid.

[0101] In some embodiments, the alkali metal salt includes one or more of sodium, potassium, rubidium, and cesium salts. In some embodiments, the alkali metal salt includes sodium or cesium salts.

[0102] In some embodiments, R5 is selected from sulfonic acid group, phosphonic acid group, carboxylic acid group, boric acid group, sodium phosphonate group, and cesium phosphonate group.

[0103] In this article, the term "sodium phosphonate" refers to the -POOH(ONa) group.

[0104] In this article, the term "cesium phosphonate" refers to the -POOH(OCs) group.

[0105] The oxyacid salt group can increase the binding ability of the terminal group to the first conductive electrode. On the other hand, the oxyacid salt group can remove alkali metal ions, and the resulting negatively charged anion can increase the molecular dipole moment, forming a strong built-in electric field at the interface, promoting hole extraction and transport, which is beneficial to improving the photoelectric conversion efficiency of the solar cell.

[0106] In some embodiments, R4 is selected from one or more of phenylene, thiopheneyl, and C2-C4 alkylene.

[0107] In this paper, the term "C2-C4 alkylene" refers to a straight-chain or branched hydrocarbon group in which the number of carbon atoms is between 2 and 4.

[0108] In some embodiments, R4 includes one or more of ethylidene, propylidene, isopropylidene, n-butylidene, sec-butylidene, isobutylidene, and tert-butylidene.

[0109] In some embodiments, R4 includes one or more of phenylene, thiophene, ethylene, propylene, and n-butylene.

[0110] In some embodiments, R4 is selected from... Or C2-C4 alkylene groups. In some embodiments, the R4 is selected from... Ethylene, propylene, butylene.

[0111] The linking groups facilitate strong interactions between the passivator and the light-absorbing layer, or increase the contact area between the passivator and the light-absorbing layer, thus fully utilizing the passivator's function, improving the overall structural integrity of the perovskite material in the perovskite layer, reducing non-radiative charge recombination at the light-absorbing layer interface, and enhancing the stability of the solar cell. Furthermore, adjusting the length of the linking groups may enhance the hydrophobicity of the passivator, blocking the influence of air and moisture on the passivator, and further improving the stability of the solar cell.

[0112] In some embodiments, when A is S, R1 and R2 are selected from one or more of hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and isobutyl.

[0113] In some embodiments, when A is S, R1 and R2 are both selected from hydrogen. In some embodiments, when A is S, R1 and R2 are both selected from methyl groups.

[0114] In some embodiments, when A is P, R1, R2, and R3 are selected from one or more of hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and isobutyl.

[0115] In some embodiments, when A is P, R1, R2, and R3 are all selected from hydrogen. In some embodiments, when A is P, R1, R2, and R3 are all selected from methyl groups.

[0116] In some embodiments, the passivating agent comprises a cation with any of the following structures:

[0117]

[0118] In some implementations, the X - Selected from halide ions or pseudohalogen ions.

[0119] In this paper, the term "pseudohalogen" refers to a group of atoms composed of two or more nonmetallic elements that have properties similar to halogens in their free state.

[0120] In some embodiments, the halide ion includes F - Cl - ,Br - I - One or more of them.

[0121] In some embodiments, the pseudohalogen includes CN. - SCN - BF4 - PF6 - One or more of them.

[0122] In some embodiments, the passivating agent is selected from any one of the following compounds:

[0123]

[0124]

[0125] The sulfonium or phosphonium ions contained in the passivator carry a positive charge and can interact with the negatively charged sites in the perovskite material, passivating surface defects and improving the photoelectric conversion efficiency of the solar cell. The oxyacid groups at the ends of the passivator can remove hydrogen ions to form negatively charged anions, while the terminal groups contain positively charged sulfonium or phosphonium ions, allowing the entire passivator molecule to form a built-in electric field at the interface between the perovskite light-absorbing layer and the first conductive electrode. When the passivator molecule ends in oxyacid salt groups, it increases the binding affinity between the terminal groups and the first conductive electrode. Furthermore, the oxyacid salt groups can remove alkali metal ions to form negatively charged anions, increasing the molecular dipole moment and creating a strong built-in electric field at the interface. This promotes hole extraction and transport, improving the photoelectric conversion efficiency and stability of the solar cell.

[0126] In some embodiments, the passivation layer 111 has a thickness of 0.1 nm to 20 nm.

[0127] In some embodiments, the passivation layer thickness 111 is 0.1nm-15nm, 0.1nm-10nm, 0.1nm-5nm, 0.5nm-20nm, 1.0nm-20nm, 1.5nm-20nm, or 2.0nm-20nm. In some embodiments, the passivation layer 111 thickness is 0.1nm, 0.5nm, 1.0nm, 2nm, 4nm, 6nm, 8nm, 10nm, 12nm, 14nm, 16nm, 18nm, 20nm, or any range between any two of the above values, or any value within any of the above ranges.

[0128] Excessive passivation layer thickness increases the hole transport path length from the perovskite light-absorbing layer to the first conductive electrode, leading to increased series resistance and hindering hole transport, causing hole recombination at the surface and affecting the cell's photoelectric conversion efficiency. Insufficient passivation layer thickness fails to completely passivate defects, causing degradation of the light-absorbing layer material. An appropriate passivation layer thickness effectively prevents non-radiative recombination of holes at the surface, reducing the probability of electrons and holes recombinating before effective separation, improving hole transport efficiency, reducing degradation of the light-absorbing layer material, and enhancing the cell's stability and photoelectric conversion efficiency.

[0129] In some embodiments, the absolute value of the energy difference between the valence band top of the light-absorbing layer and the work function of the first conductive electrode does not exceed 0.5 eV. In some embodiments, the energy difference between the valence band top of the light-absorbing layer and the work function of the first conductive electrode does not exceed 0.4 eV, 0.3 eV, 0.2 eV, or 0.1 eV.

[0130] In this paper, the term "valence band top of the light-absorbing layer" refers to the energy of the highest energy level in the valence band of the light-absorbing layer material, and its value is given with reference to the Fermi level. For example, if the Fermi level is set to 0 eV, the energy level of the valence band top will be given as a value relative to the Fermi level.

[0131] In this document, the term "work function of a conductive electrode" refers to the minimum energy required for an electron to move from the surface of a conductive electrode to a vacuum. Its value is the energy difference between the Fermi level of the conductive electrode and the vacuum level, which is its work function. In some embodiments, when the first conductive electrode is a conductive substrate, the work function of the first conductive electrode is the minimum energy required for an electron to move from the surface of the conductive substrate to a vacuum.

[0132] In this article, "conductive substrate" refers to an electrode with high conductivity and high visible light transmittance.

[0133] The method for testing the valence band top of the light-absorbing layer can be any method known in the art. For example, it can be measured using methods such as ultraviolet photoelectron spectroscopy or X-ray photoelectron spectroscopy.

[0134] The work function of a conductive electrode can be tested using methods known in the art; for example, it can be measured using photoelectron spectroscopy or reverse emission spectroscopy.

[0135] In some embodiments, the valence band top of the light-absorbing layer is -5.1 eV, and the work function of the first conductive electrode is -4.7 eV.

[0136] The smaller the energy difference between the top of the valence band of the light-absorbing layer and the work function of the first conductive electrode, the closer they are. This is more conducive to the transmission of holes through tunneling, can improve the extraction efficiency of holes at the interface, and can reduce non-radiative recombination at the interface, thereby improving the stability and photoelectric conversion efficiency of the battery.

[0137] In some embodiments, the light-absorbing layer 112 comprises a perovskite compound.

[0138] In some embodiments, the perovskite compound crystal structure satisfies at least one of ABX3 and / or A2CDX6; wherein A, B, C, and D are all inorganic, organic, or mixed organic-inorganic cations, and A is a monovalent cation, including Cs. + CH3NH 3+ (methylamine ion or MA) + ), NH2CH=NH2+ (formamidinium ion or FA) + At least one of the following: B is a divalent cation, including Pb. 2+ Sn 2+ At least one of them, Pb 2+ or Sn 2+ C can be Ag + D can be Bi 3+ Sb 3+ In 3+ At least one of the following; X is an inorganic, organic, or mixed organic-inorganic anion, X including Br - I - At least one of them.

[0139] In some embodiments, the perovskite compound includes MA 0.3 FA 0.7 Pb 0.5 Sn 0.5 I3.

[0140] In some embodiments, the perovskite compound has a band gap of 1.20 eV-2.30 eV.

[0141] In some embodiments, the band gap of the perovskite compound may be selected as 1.50 eV-2.30 eV, 1.70 eV-2.30 eV, 1.90 eV-2.30 eV, 2.0 eV-2.30 eV, or 2.20 eV-2.30 eV. In some embodiments, the band gap of the perovskite compound is 1.20 eV, 1.30 eV, 1.40 eV, 1.50 eV, 1.60 eV, 1.70 eV, 1.80 eV, 1.90 eV, 2.00 eV, 2.10 eV, 2.20 eV, 2.30 eV, or a range between any two of the above values, or any value within any of the above ranges.

[0142] With the band gap of the perovskite light-absorbing layer within the aforementioned range, the solar cell can absorb more photons across the spectral range, further improving the cell's photoelectric conversion efficiency.

[0143] In some embodiments, the thickness of the light-absorbing layer 112 is 200nm-1000nm.

[0144] In some embodiments, the thickness of the light-absorbing layer 112 can be selected as 300nm-1000nm, 400nm-1000nm, 500nm-1000nm, 600nm-1000nm, 700nm-1000nm, 800nm-1000nm, or 900nm-1000nm. In some embodiments, the thickness of the light-absorbing layer 112 is 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1000nm, or any range between any two of the above values, or any value within any of the above ranges.

[0145] With the thickness of the perovskite light-absorbing layer 112 within a suitable range, the solar cell can not only absorb a wide range of solar spectra, but also has excellent charge transport performance.

[0146] In some embodiments, the electron transport layer 113 includes [6,6]-phenylC 61 Methyl butyrate (PC) 61 BM), [6,6]-phenyl C 71 Methyl butyrate (PC) 71 BM), Fullerene C 60 (C 60 ), fullerene C 70 (C 70 At least one of the following: tin dioxide (SnO2), zinc oxide (ZnO), perylene imide (PDI) materials, naphthalene imide (NDI) materials, and their derivatives, as well as materials obtained by doping or passivation.

[0147] In some embodiments, the thickness of the electron transport layer 113 is 5 nm to 100 nm.

[0148] In some embodiments, the thickness of the electron transport layer 113 is 10nm-100nm, 20nm-100nm, 30nm-100nm, 40nm-100nm, 50nm-100nm, 60nm-100nm, 70nm-100nm, 80nm-100nm, or 90nm-100nm. In some embodiments, the thickness of the electron transport layer 113 is 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, or 100nm, or any range between any two of these values, or any value within any of the aforementioned ranges.

[0149] In some embodiments, the first conductive electrode 10 includes a conductive substrate, which includes FTO (fluorine-doped SnO2 transparent conductive glass, SnO2:F), ITO (indium tin oxide transparent conductive glass), AZO (Al-doped ZnO transparent conductive glass), BZO (B-doped ZnO transparent conductive glass) and / or IZO (indium zinc oxide transparent conductive glass).

[0150] In some embodiments, the thickness of the first conductive electrode 10 is 10 nm to 1000 nm.

[0151] In some embodiments, the thickness of the first conductive electrode 10 is 50nm-1000nm, 100nm-1000nm, 150nm-1000nm, 200nm-1000nm, 400nm-1000nm, 600nm-1000nm, 800nm-1000nm, or 900nm-1000nm. In some embodiments, the thickness of the conductive substrate is 50nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, 850nm, 900nm, 950nm, or 1000nm, or any range between any two of these values, or any value within any of the aforementioned ranges.

[0152] In some embodiments, the second conductive electrode 12 is a metal electrode, which is an organic, inorganic, or organic-inorganic mixed conductive material, including but not limited to Ag, Cu, C, Au, Al, ITO, AZO, BZO, and IZO.

[0153] In some embodiments, the thickness of the second conductive electrode 12 is 10nm-1000nm.

[0154] In some embodiments, the thickness of the second conductive electrode 12 is 50nm-1000nm, 100nm-1000nm, 150nm-1000nm, 200nm-1000nm, 400nm-1000nm, 600nm-1000nm, 800nm-1000nm, or 900nm-1000nm. In some embodiments, the thickness of the second conductive electrode 12 is 50nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, 850nm, 900nm, 950nm, or 1000nm, or a range between any two of these values, or any value within any of the aforementioned ranges.

[0155] In some embodiments, a barrier layer is also present between the electron transport layer 113 and the second conductive electrode 12.

[0156] In some embodiments, the conduction band bottom of the blocking layer is lower than the conduction band bottom of the light-absorbing layer. In some embodiments, the valence band top of the blocking layer is higher than the valence band top of the light-absorbing layer.

[0157] In this paper, the term "conduction band bottom" refers to the lowest energy state that an electron can occupy; it is the lowest energy level of the conduction band.

[0158] In this paper, the term "valence band top" refers to the highest energy state that an electron can occupy, which is the highest energy level of the conduction band.

[0159] The conduction band bottom of the blocking layer is lower than that of the perovskite absorbing layer, meaning that the blocking layer facilitates electron transport. The valence band top of the blocking layer is higher than that of the perovskite absorbing layer, which effectively prevents the back diffusion of holes.

[0160] In some embodiments, the thickness of the barrier layer is 0.5 nm-20 nm. In some embodiments, the thickness of the barrier layer is 1 nm-20 nm, 2 nm-20 nm, 4 nm-20 nm, 5 nm-15 nm, 8 nm-20 nm, 12 nm-20 nm, 16 nm-20 nm, or 18 nm-20 nm. In some embodiments, the thickness of the barrier layer is 0.5 nm, 1 nm, 2 nm, 4 nm, 6 nm, 8 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, or a range between any two of these values, or any value within any of the aforementioned ranges.

[0161] In some embodiments, the barrier layer comprises one or more of 2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline, tin oxide (SnO2), zinc oxide (ZnO), and cerium oxide.

[0162] In some embodiments, the first conductive electrode includes a conductive substrate, and the second conductive electrode includes a metal electrode. In some embodiments, the first conductive electrode is a metal electrode, and the second conductive electrode is a conductive substrate.

[0163] In some embodiments, the solar cell includes a conductive substrate, a passivation layer, a light-absorbing layer, an electron transport layer, and a second conductive electrode stacked sequentially from bottom to top, wherein the passivation layer includes a passivating agent as shown in Formula I.

[0164] A second aspect of this application provides a method for preparing a solar cell, comprising:

[0165] Provide a first conductive electrode;

[0166] A passivation layer is prepared on one side of the first conductive electrode;

[0167] A light-absorbing layer is prepared on the side of the passivation layer away from the first conductive electrode;

[0168] An electron transport layer is prepared on the side of the light-absorbing layer away from the passivation layer;

[0169] A second conductive electrode is fabricated on the side of the electron transport layer away from the light-absorbing layer;

[0170] The passivation layer includes the passivating agent shown in Formula I.

[0171]

[0172] Where A is selected from S or P;

[0173] R1, R2, and R3 are each independently selected from hydrogen and C1-C4 alkyl groups; R3 is present when A is P; R3 is absent when A is S.

[0174] R4 is selected from one or more of C6-C10 arylene, C6-C10 heteroarylene, and C1-C6 alkylene;

[0175] R5 is selected from oxyacid groups or oxyacid salt groups;

[0176] X - It is a negative monovalent ion.

[0177] The method for preparing solar cells reduces the need for hole transport layer preparation, shortens the process flow, and lowers the production cost of solar cells.

[0178] In some embodiments, the passivation layer is prepared by a method comprising the following steps:

[0179] The passivating agent shown in Formula I is dissolved in water or an organic solvent to obtain a passivating material. The passivating material is then coated onto one side of the first conductive electrode to obtain a passivation layer.

[0180] The process for preparing the passivation layer of solar cells is mature and controllable, which is beneficial to the stability of solar cell production quality.

[0181] In some embodiments, the concentration of the passivating agent in the passivation layer is 0.0001 mmol / mL to 0.1 mmol / mL.

[0182] In some embodiments, the concentration of the passivating agent in the passivation layer is 0.0001 mmol / mL-0.05 mmol / mL, 0.0001 mmol / mL-0.01 mmol / mL, 0.0001 mmol / mL-0.005 mmol / mL, 0.0001 mmol / mL-0.001 mmol / mL, 0.0001 mmol / mL-0.0005 mmol / mL, 0.001 mmol / mL-0.005 mmol / mL, 0.001 mmol / mL-0.01 mmol / mL, or 0.001 mmol / mL-0.05 mmol / mL. In some embodiments, the concentration of the passivating agent in the passivation layer is 0.0001 mmol / mL, 0.0005 mmol / mL, 0.001 mmol / mL, 0.005 mmol / mL, 0.01 mmol / mL, 0.05 mmol / mL, 0.1 mmol / mL, or any two of these values, or any value within any of these ranges. A suitable concentration of the passivating agent in the passivation layer facilitates the application of the passivating material to form a passivation layer of appropriate thickness.

[0183] In some embodiments, the passivation layer and the light-absorbing layer are prepared by a method including the following steps:

[0184] The passivating agent shown in Formula I is dissolved in a light-absorbing layer active material precursor solution to obtain an in-situ passivating material. The in-situ passivating material is then coated on one side of the first conductive electrode to obtain a passivation layer coated on one side of the first conductive electrode and a light-absorbing layer located on the side of the passivation layer away from the first conductive electrode.

[0185] The method described above facilitates the one-step preparation of the light-absorbing layer and the passivation layer through in-situ passivation, reducing the process steps. Unbound by any theoretical constraints, intermolecular forces or chemical reactions may exist between the passivating agent shown in Formula I and the active material of the light-absorbing layer in the precursor solution, causing the passivating agent molecules to spontaneously form different layers with the active material of the light-absorbing layer, with the passivating agent molecules forming a passivation layer on the surface of the light-absorbing layer.

[0186] In some embodiments, the light-absorbing layer active material precursor solution includes lead halide.

[0187] In some embodiments, the molar ratio of the passivating agent represented by Formula I to the lead halide in the in-situ passivation material is 0.1%-10%.

[0188] In some embodiments, the molar ratio of the passivating agent shown in Formula I to the lead halide in the in-situ passivation material is 0.1%-8%, 0.1%-6%, 0.1%-4%, 0.1%-2%, or 0.1%-1%. In some embodiments, the molar ratio of the passivating agent shown in Formula I to the lead halide in the in-situ passivation material is 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, or any range between any two of the stated values, or any value within any of the stated ranges.

[0189] When a passivating compound is added to the precursor solution of the light-absorbing layer active material, the oxyacid groups or oxyacid salt groups in the passivating agent spontaneously combine with and seal the perovskite defect sites through coordination, reducing non-radiative recombination centers and playing an in-situ passivation role, thereby improving the stability of the solar cell. At the same time, the oxyacid groups or oxyacid salt groups can form negatively charged anions, which, together with positively charged thionium or phosphonium ions, form a built-in electric field at the interface between the perovskite light-absorbing layer and the first conductive electrode, promoting hole extraction and transport, and improving the photoelectric conversion efficiency of the solar cell.

[0190] A third aspect of this application provides an electrical device, including a solar cell according to an embodiment of this application or a solar cell prepared by a preparation method according to an embodiment of this application.

[0191] A fourth aspect of this application provides a power generation device, including a solar cell according to an embodiment of this application or a solar cell prepared by a preparation method according to an embodiment of this application.

[0192] In some embodiments, solar cells can be used as power generation devices for electrical devices. The type of power generation device may include, but is not limited to, integrated power generation. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, tablets, laptops, calculators, watches, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), automobiles, electric trains, ships and satellites, power generation systems, etc. The location of the power generation device may include, but is not limited to, the roof or back panel of a vehicle.

[0193] Example

[0194] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0195] I. Preparation of passivating agent

[0196] Preparation Example 1: At room temperature (20℃-30℃), 20 ml of anhydrous dichloromethane was added to a reaction vessel. Nitrogen gas was then introduced to purge air. 20 mmol of (3-bromopropyl)boric acid was added, and the mixture was stirred until dissolved. The reaction solution was heated to 40℃, and 1 mol (approximately 22 L) of hydrogen sulfide gas was introduced. The tail gas generated during the reaction was collected using an aqueous sodium hydroxide solution. The mixture was refluxed and stirred for 24 h. After the reaction was complete, the solvent was removed by rotary evaporation to obtain the crude product. Recrystallization with ethanol yielded a white solid, which was then vacuum dried to obtain the passivating agent. The yield was 90%.

[0197] Preparation Examples 2-5: The preparation methods of Preparation Examples 2-4 are basically the same as those of Preparation Example 1, and the preparation methods of Preparation Example 5 are basically the same as those of Preparation Example 3. For specific differences, please refer to Table 1.

[0198] Preparation Example 6: At room temperature (20℃-30℃), 0.99 g (15.9 mmol) of dimethyl sulfide and 10 mL of acetonitrile were first added to the reaction vessel, followed by 0.81 g (5.3 mmol) of 4-bromopropionic acid. The mixture was stirred, and after the reaction was complete, the solid at the bottom of the reaction vessel was collected and repeatedly washed with diethyl ether to obtain the crude product. Recrystallization with ethanol yielded a white solid, which was then dried under vacuum to obtain the passivating agent.

[0199] Preparation Example 7: The preparation method of Preparation Example 7 is basically the same as that of Preparation Example 6. For specific differences, please refer to Table 1.

[0200] Preparation Example 8: At room temperature, 20 ml of anhydrous dichloromethane was added to a flask, and nitrogen gas was introduced into the reaction vessel to purge air. Then, 50 mmol of trimethylphosphine and 20 mmol of (3-bromopropyl)phosphoric acid were added to the reaction vessel. The reaction solution was heated to 40 °C and stirred under reflux for 24 h. After the reaction was completed, the solvent was removed by rotary evaporation to obtain the crude product. Recrystallization from ethanol yielded a white solid, which was then dried under vacuum to obtain the passivating agent. The yield was 85%.

[0201] Preparation Examples 9-10: The preparation methods of Preparation Examples 9-10 are basically the same as those of Preparation Example 6. For specific differences, please refer to Table 1.

[0202] Preparation Example 11: At room temperature, 6 g (3 mmol) of the passivating agent of formula II-6 was dissolved in 5 mL of ethanol and added to a reaction vessel. Separately, 10 mL of a 1 mol / L NaOH aqueous solution was prepared and added to the above solution. The solution was stirred and dissolved, then concentrated. The precipitated solid was filtered and repeatedly washed with diethyl ether to obtain a white solid, which was then dried under vacuum to obtain the passivating agent. The yield is 30%.

[0203] Preparation Example 12: The preparation method of Preparation Example 12 is basically the same as that of Preparation Example 11. The specific differences in parameters are shown in Table 1.

[0204] Preparation Example 13: 8.41 g (0.05 mol) of 4-methylthiobenzoic acid (CAS: 13205-48-6) and 6.9 g (0.055 mol) of dimethyl sulfate were mixed and stirred at room temperature. After the reaction was complete, 100 mL of deionized water and 50 mL of diethyl ether were added for extraction to obtain an aqueous solution of 4-thiothiobenzoic acid sulfate. The solvent was removed by rotary evaporation to obtain the crude product, which was then dried under vacuum to obtain the passivating agent.

[0205] Preparation Example 14:

[0206] The preparation method of Preparation Example 14 is basically the same as that of Preparation Example 13. The specific differences in parameters are shown in Table 1.

[0207] Table 1

[0208]

[0209]

[0210] II. Fabrication and Performance Testing of Solar Cells

[0211] Example 1

[0212] Fabrication of a transparent conductive electrode (conductive substrate): 2.0 × 2.0 cm in size. 2 Fluorine-doped tin oxide transparent conductive glass (FTO conductive glass) was used. 0.35 cm of FTO conductive glass was removed from each end by laser etching, exposing the glass substrate. The etched FTO conductive glass was then ultrasonically cleaned sequentially with water, acetone, and isopropanol, and dried with nitrogen gas for later use as a conductive substrate. The work function of the conductive substrate was -4.7 eV.

[0213] Preparation of passivation layer: The passivating agent (Formula II-1) was dissolved in methanol at a concentration of 1 mg / mL to obtain the passivation material. The passivation material was spin-coated on a conductive substrate at 3000 rpm and annealed at 100℃ for 10 min to obtain a passivation layer with a thickness of 5 nm.

[0214] Preparation of the perovskite absorbing layer: Weigh 1.19 mmol formamidinium iodide, 0.51 mmol methylamine iodide, 0.85 mmol lead iodide, 0.85 mmol stannous iodide, and 0.085 mol stannous fluoride, and dissolve them in 1 mL of a 2:1 mixture of DMF (dimethylformamide) and DMSO (dimethyl sulfoxide). Stir for 2 h, and filter through a 0.22 μm organic filter membrane to obtain MA. 0.3 FA 0.7 Pb 0.5 Sn 0.5 I3 solution, MA was spin-coated onto the passivation layer at 5000 rpm. 0.3 FA 0.7 Pb 0.5 Sn 0.5 I3 solution was applied for 30 seconds, and 400 μL of chlorobenzene was added dropwise to the center of the substrate in the last 5 seconds. The substrate was then annealed at 100 °C for 40 min and cooled to room temperature to obtain a perovskite absorbing layer with a thickness of 800 nm. The valence band top of the perovskite absorbing layer was -5.1 eV.

[0215] Preparation of the electron transport layer: Methyl [6,6]-phenyl-C61-butyrate (PCBM) was spin-coated onto the perovskite light-absorbing layer at 1500 rpm, annealed at 100 °C for 10 min, and then a blocking layer material, 2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline (BCP), was spin-coated at 5000 rpm. The electron transport layer had a thickness of 50 nm, and the blocking layer had a thickness of 10 nm.

[0216] Preparation of metal electrodes: The thin film with the electron transport layer is placed in an evaporation apparatus, and the evaporation vacuum is allowed to reach 5 × 10⁻⁶. -4 Solar cell 1 was prepared by evaporating an 80 nm metal back electrode Ag at a rate of 0.1 A / s below Pa.

[0217] Example 2-14

[0218] The preparation methods of Examples 2-14 are basically the same as those of Example 1, except that the type of passivating agent is adjusted in the passivation layer preparation step, as detailed in Table 1.

[0219] Example 15

[0220] The preparation method of Example 15 is basically the same as that of Example 1, except that:

[0221] The preparation steps for the passivation layer are excluded; and the preparation method for the perovskite light-absorbing layer is modified as follows: Weigh 1.19 mmol formamidin iodine, 0.51 mmol methylamine iodine, 0.85 mmol lead iodide, 0.85 mmol stannous iodide, 0.085 mol stannous fluoride, and 0.17 mmol passivating agent compound 7, dissolve them in 1 mL of a mixed solution of DMF (dimethylformamide) and DMSO (dimethyl sulfoxide) in a volume ratio of 2:1, stir for 2 h, filter with a 0.22 μm organic filter membrane to obtain a perovskite precursor solution, spin coat the perovskite precursor solution at 5000 rpm for 30 s, add 400 μL chlorobenzene to the center of the substrate in the last 5 s, anneal at 100 °C for 40 min, cool to room temperature, and obtain a perovskite light-absorbing layer with a thickness of 800 nm.

[0222] Examples 16-17

[0223] The preparation methods of Examples 16-17 are basically the same as those of Example 15, except that the type of passivating agent is adjusted when preparing the perovskite light-absorbing layer, as detailed in Table 2.

[0224] Comparative Example 1

[0225] The preparation method of Comparative Example 1 is basically the same as that of Example 1, except that no passivation layer is prepared.

[0226] The solar cells prepared in Examples 1-17 and Comparative Example 1 were tested using the following methods:

[0227] 1. Photoelectric conversion efficiency and stability test

[0228] The test was conducted using a solar simulator (Guangyan Technology) according to the national standard IEC61215. A crystalline silicon solar cell was used to correct the light intensity to achieve a solar intensity of AM1.5. The test cell was connected to a digital source meter, and its photoelectric conversion efficiency was measured under illumination. The test voltage range was -0.2V to 1.2V, and the scan rate was 50mV / s. The maximum photoelectric conversion efficiency is the highest efficiency of the test cell after 1-10 days of natural aging. The photoelectric conversion efficiency on day 30 is the photoelectric conversion efficiency after 30 days of storage in nitrogen in the dark. Stability, i.e., the retention rate of the maximum photoelectric conversion efficiency, is the ratio of the photoelectric conversion efficiency on day 30 to the maximum photoelectric conversion efficiency.

[0229] The test results of Examples 1-15 and Comparative Example 1 are shown in Table 2:

[0230] Table 2

[0231]

[0232] In Examples 1-17, the solar cell includes a conductive substrate, a passivation layer, a light-absorbing layer, an electron transport layer, and a metal electrode stacked sequentially from bottom to top. The passivation layer includes passivating agents shown in Formulas II-1 to II-14. Compared with the solar cell without a passivation layer in Comparative Example 1, the solar cells of Examples 1-17 have both good photoelectric conversion efficiency and stability.

[0233] In Examples 1-10, the passivating agents for the solar cells respectively include oxyacid groups (boronic acid, sulfonic acid, carboxylic acid, and phosphonic acid groups), resulting in solar cells that balance good photoelectric conversion efficiency and stability. In Examples 11-12, the passivating agents for the solar cells include oxyacid salt groups (sodium phosphonate and cesium phosphonate), resulting in solar cells that balance excellent maximum photoelectric conversion efficiency and stability. A comparison of Examples 11-12 with Example 10 shows that, compared to phosphonic acid groups, the presence of sodium phosphonate or cesium phosphonate groups in the passivating agent can further improve the maximum photoelectric conversion efficiency of the solar cells.

[0234] In Examples 7 and 9-10, the linking group in the solar cell passivator is a C2-C4 alkylene group, resulting in solar cells that balance excellent photoelectric conversion efficiency and stability. A comparison of Examples 7 and 10 with Example 9 shows that, compared to ethylene, using propylene or n-butylene as the linking group can further improve the stability of the solar cell.

[0235] In Examples 13-14, the linking groups in the passivating agent of the solar cell are phenylene and thiophene, respectively. The solar cell achieves both excellent photoelectric conversion efficiency and stability, with the stability being significantly improved.

[0236] In Examples 15-17, the passivation layer and light-absorbing layer of the solar cell are prepared in a one-step process. The passivating agent molecules and the precursor solution of the light-absorbing layer active material are passivated in situ, achieving the preparation of both the passivation layer and the light-absorbing layer in one step. Compared with the solar cell without a passivation layer in Comparative Example 1, the solar cells of Examples 15-17 exhibit both good photoelectric conversion efficiency and stability. Compared with Examples 7 and 11-12, the solar cells prepared by the one-step process and those prepared by methods including the passivation layer preparation step have essentially equivalent photoelectric conversion efficiency and stability. It is understood that the passivating agent provided in this application is flexible in its use and can be applied to solar cells using different methods.

[0237] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A solar cell, characterized in that, The solar cell comprises a first conductive electrode, a passivation layer, a light-absorbing layer, an electron transport layer, and a second conductive electrode, which are stacked sequentially. The passivation layer comprises a passivating agent as shown in Formula I. Equation I Where A is selected from S or P; R1, R2, and R3 are each independently selected from hydrogen and C1-C4 alkyl groups; R3 is present when A is P; R3 is absent when A is S. R4 is selected from one or more of C6-C10 arylene, C6-C10 heteroarylene, and C1-C6 alkylene; R5 is selected from oxyacid groups or oxyacid salt groups; X - It is a negative monovalent ion; The oxyacid groups include one or more of the following: sulfonic acid group, phosphonic acid group, carboxylic acid group, boric acid group, and hypophosphonic acid group; The oxyacid salt groups include one or more alkali metal salts of sulfonic acid, phosphonic acid, carboxylic acid, boric acid, and hypophosphonic acid groups.

2. The solar cell according to claim 1, characterized in that, The alkali metal salt includes one or more of sodium salt, potassium salt, rubidium salt, and cesium base.

3. The solar cell according to claim 1, characterized in that, The R5 is selected from sulfonic acid group, phosphonic acid group, carboxylic acid group, boric acid group, sodium phosphonate group, and cesium phosphonate group.

4. The solar cell according to claim 1, characterized in that, R4 is selected from , Or C2-C4 alkylene groups.

5. The solar cell according to claim 1, characterized in that, R1, R2, and R3 are all selected from hydrogen or methyl.

6. The solar cell according to claim 1, characterized in that, X - Selected from halide ions or pseudohalogen ions.

7. The solar cell according to claim 6, characterized in that, The halide ions include F - Cl - ,Br - I - One or more of the following; The pseudohalogen includes CN. - SCN - BF4 - PF6 - One or more of them.

8. The solar cell according to claim 1, characterized in that, The passivating agent is selected from any one of the following compounds:

9. The solar cell according to claim 1, characterized in that, The passivation layer has a thickness of 0.1 nm to 20 nm.

10. The solar cell according to claim 1, characterized in that, The absolute value of the energy difference between the top of the valence band of the light-absorbing layer and the work function of the first conductive electrode does not exceed 0.5 eV.

11. The solar cell according to claim 1, characterized in that, The light-absorbing layer comprises a perovskite compound, which includes at least one of ABX3 and / or A2CDX6, wherein C and D are inorganic, organic, or mixed organic-inorganic cations, and A is a monovalent cation, including Cs. + CH3NH 3+ NH2CH=NH 2+ At least one of them; B is a divalent cation, including Pb 2+ Sn 2+ At least one of them; X includes Br - I - At least one of them; The first conductive electrode includes at least one of fluorine-doped tin oxide, indium tin oxide, aluminum-doped zinc oxide, boron-doped indium zinc oxide, and indium-doped zinc oxide.

12. The solar cell according to claim 11, characterized in that, B is Pb 2+ or Sn 2+ .

13. The solar cell according to claim 11, characterized in that, C is Ag + ; and / or, D is Bi 3+ Sb 3+ In 3+ One or more of them.

14. The solar cell according to any one of claims 1 to 13, characterized in that, A barrier layer is disposed between the electron transport layer and the second conductive electrode, and the barrier layer satisfies at least one of the following: (1) The bottom of the conduction band of the blocking layer is lower than the bottom of the conduction band of the light-absorbing layer, or The valence band top of the blocking layer is higher than the valence band top of the light-absorbing layer; (2) The thickness of the barrier layer is 0.5nm-20nm; (3) The barrier layer comprises one or more of 2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline, SnO2, ZnO and cerium oxide.

15. The solar cell according to claim 1, characterized in that, The first conductive electrode includes a conductive substrate, and the second conductive electrode includes a metal electrode.

16. A method for preparing a solar cell, characterized in that, include: Provide a first conductive electrode; A passivation layer is prepared on the surface of one side of the first conductive electrode; A light-absorbing layer is prepared on the side of the passivation layer away from the first conductive electrode; An electron transport layer is prepared on the side of the light-absorbing layer away from the passivation layer; A second conductive electrode is fabricated on the side of the electron transport layer away from the light-absorbing layer; The passivation layer includes the passivating agent shown in Formula I. Equation I Where A is selected from S or P; R1, R2, and R3 are each independently selected from hydrogen and C1-C4 alkyl groups; R3 is present when A is P; R3 is absent when A is S. R4 is selected from one or more of C6-C10 arylene, C6-C10 heteroarylene, and C1-C6 alkylene; R5 is selected from oxyacid groups or oxyacid salt groups; X - It is a negative monovalent ion; The oxyacid groups include one or more of the following: sulfonic acid group, phosphonic acid group, carboxylic acid group, boric acid group, and hypophosphonic acid group; The oxyacid salt groups include one or more alkali metal salts of sulfonic acid, phosphonic acid, carboxylic acid, boric acid, and hypophosphonic acid groups.

17. The preparation method according to claim 16, characterized in that, The passivation layer is prepared by a method comprising the following steps: The passivating agent shown in Formula I is dissolved in water or an organic solvent to obtain a passivating material. The passivating material is then coated onto one side of the first conductive electrode to obtain a passivation layer.

18. The preparation method according to claim 17, characterized in that, The concentration of the passivating agent in the passivating material is 0.0001 mmol / mL to 0.1 mmol / mL.

19. The preparation method according to any one of claims 16 to 18, characterized in that, The passivation layer and the light-absorbing layer are prepared by a method including the following steps: The passivating agent shown in Formula I is dissolved in a light-absorbing layer active material precursor solution to obtain an in-situ passivating material. The in-situ passivating material is then coated on one side of the first conductive electrode to obtain a passivation layer coated on one side of the first conductive electrode and a light-absorbing layer located on the side of the passivation layer away from the first conductive electrode.

20. The preparation method according to claim 19, characterized in that, The light-absorbing layer active material precursor solution includes lead halide, and the molar ratio of the passivating agent shown in Formula I to the lead halide is 0.1%-10%.

21. An electrical appliance, characterized in that, The solar cell includes any one of claims 1 to 15 or a solar cell prepared by the preparation method of any one of claims 16 to 20.

22. A power generation device, characterized in that, The solar cell includes any one of claims 1 to 15 or a solar cell prepared by the preparation method of any one of claims 16 to 20.

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