Solar cell and preparation method thereof, power utilization device and power generation device

Abstract

The invention discloses a solar cell and a preparation method thereof, a power utilization device and a power generation device, and the solar cell is characterized in that a functional layer comprising a covalent organic framework material and an ammonium salt is introduced between a first charge transmission layer and a light absorption layer, and defect passivation is realized while perovskite crystallization is regulated and controlled; meanwhile, the covalent organic framework material can adsorb gas generated by decomposition of ammonium salt and gas generated by decomposition of organic amine cations in the perovskite material, and the two gases have at least part of the same components, that is, in the covalent organic framework material system, the gas generated by decomposition of the ammonium salt and the gas generated by decomposition of organic amine cations in the perovskite material are separated from each other. Compared with the prior art, the amount of the gas with the same components as the gas generated by decomposition of the organic amine cations in the perovskite material is increased, so that the decomposition reaction of the organic amine cations in the perovskite material is close to an equilibrium state, the decomposition reaction of the perovskite material is inhibited, the stability of the perovskite material is improved, and the service life of the perovskite material is prolonged. And the stability of the solar cell is improved.

Description

Technical Field

[0001] The present application relates to the field of solar cells, and in particular to a solar cell and a preparation method thereof, an electrical device and a power generation device. Background Art

[0002] In recent years, energy security and environmental pollution have increasingly drawn public attention. Solar energy, as a clean, pollution-free, and renewable energy source, is considered the ultimate solution to both these issues. Against this backdrop, perovskite solar cells, a new type of solar cell, have rapidly developed due to a range of advantages, with the highest current photoelectric conversion efficiency exceeding 25%. However, to achieve industrialization, continuous improvements in stability and efficiency remain crucial. Therefore, developing a highly stable solar cell, its preparation method, and its power-consuming and power-generating devices are pressing technical challenges. Summary of the Invention

[0003] In view of this, the main technical problem to be solved by the present application is to provide a solar cell and a preparation method thereof, an electrical device and a power generation device, so as to improve the stability of solar cell devices.

[0004] The present application provides a solar cell, comprising at least:

[0005] a first charge transport layer;

[0006] a light absorbing layer, the light absorbing layer comprising a perovskite material, wherein cations of the perovskite material comprise organic amine cations; and

[0007] The functional layer is located between the first charge transport layer and the light absorption layer, and includes a covalent organic framework material and an ammonium salt.

[0008] The present application introduces a functional layer including a covalent organic framework material and an ammonium salt between the first charge transport layer and the light absorption layer to regulate the crystallization of the perovskite while achieving defect passivation; at the same time, the covalent organic framework material can adsorb the gas produced by the decomposition of the ammonium salt and the gas produced by the decomposition of the organic amine cations in the perovskite material, and these two gases have at least partially the same composition, that is, in the covalent organic framework material system, the amount of gas with the same composition as the gas produced by the decomposition of the organic amine cations in the perovskite material increases, so that the decomposition reaction of the organic amine cations in the perovskite material is close to the equilibrium state, thereby inhibiting the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and then improving the stability of the solar cell.

[0009] In some embodiments, the cation of the perovskite material includes at least one of formamidine cations, methylamine cations, and guanidinium cations; and the ammonium salt includes an ammonium salt whose decomposition product contains at least one of methylamine, formamidine, guanidine, and ammonia.

[0010] In the embodiment provided in the present application, the perovskite material is within the above-mentioned range, and the covalent organic framework material can adsorb the gas generated by the decomposition of the ammonium salt and the gas generated by the decomposition of the organic amine cation in the perovskite material, and the two gases have at least partially the same components, that is, in the covalent organic framework material system, the amount of gas with the same components as the gas generated by the decomposition of the organic amine cation in the perovskite material is increased, so that the decomposition reaction of the organic amine cation in the perovskite material is close to the equilibrium state, thereby inhibiting the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and then improving the stability of the solar cell.

[0011] In one embodiment, the cation of the ammonium salt includes at least one of a formamidinium cation, a methylamine cation, a guanidinium cation, and an ammonium cation. The gas generated by the decomposition of the ammonium salt and the gas generated by the decomposition of the organic amine cation in the perovskite material have at least partially the same composition. That is, in the covalent organic framework material system, the amount of gas with the same composition as the gas generated by the decomposition of the organic amine cation in the perovskite material increases, thereby bringing the decomposition reaction of the organic amine cation in the perovskite material close to equilibrium, thereby suppressing the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and further improving the stability of the solar cell.

[0012] In some embodiments, the ammonium salt comprises at least one of methylamine hydrohalide, formamidine hydrohalide, guanidine hydrohalide, ammonium carbonate, and ammonium bicarbonate. It is understood that hydrohalide includes but is not limited to hydroiodide, hydrofluoride, hydrochloride, and hydrobromide.

[0013] In the embodiment provided in the present application, the gas generated by the decomposition of the above-mentioned ammonium salt can make the decomposition reaction of the organic amine cation in the perovskite material close to the equilibrium state, thereby inhibiting the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and further improving the stability of the solar cell.

[0014] In some embodiments, the amount of the ammonium salt is 1% to 20% of the amount of the covalent organic framework material.

[0015] In the embodiment provided in the present application, the amount of the ammonium salt is within the above range, which is beneficial to inhibiting the degradation of the perovskite material and the stability of the film layer, thereby improving the stability of the solar cell.

[0016] In some embodiments, the covalent organic framework material includes at least one of a N atom having a lone pair of electrons and a S atom having a lone pair of electrons.

[0017] In the embodiment provided in the present application, the covalent organic framework material is within the above-mentioned range, and the N atoms and S atoms containing lone pair electrons in the covalent organic framework material can be complexed with the uncoordinated lead ions in the perovskite material, thereby reducing the deep energy level defect concentration, being able to regulate the crystallization of the perovskite while achieving defect passivation, and improving the stability of the solar cell.

[0018] In some embodiments, the covalent organic framework material is a framework structure formed by connecting several A units and several B units, or a framework structure formed by connecting several A units, wherein the A unit includes a conjugated structure having a carboxyl group or an amine group, and the B unit includes any one of an alkyl chain, a chain structure containing a benzene ring, and a chain structure containing a heterocycle.

[0019] In the embodiments provided in the present application, the covalent organic framework material can regulate the crystallization of the perovskite while achieving defect passivation within the above-mentioned range, and can adsorb the gases generated by the decomposition of ammonium salts and the gases generated by the decomposition of organic amine cations in the perovskite material, thereby inhibiting the degradation of the perovskite material and improving the stability of the solar cell.

[0020] In one embodiment, unit A comprises the following structure:

[0021]

[0022] At this time, covalent organic framework materials can regulate the crystallization of perovskite while achieving defect passivation and improving the stability of solar cells.

[0023] In some embodiments, the electrical conductivity of the covalent organic framework material is 10 -8 S m -1 ~10 -2 S m -1 .

[0024] In the embodiment provided in the present application, the electrical conductivity of the covalent organic framework material is within the above-mentioned range, and while being able to regulate the crystallization of perovskite, defect passivation is achieved. It is able to adsorb gases generated by the decomposition of ammonium salts and gases generated by the decomposition of organic amine cations in the perovskite material, inhibit the degradation of the perovskite material, and is also beneficial to the transmission of charges. Therefore, it not only improves the stability of the solar cell, but also maintains a good photoelectric conversion efficiency of the solar cell.

[0025] In some embodiments, the porosity of the covalent organic framework material is 50% to 90%.

[0026] In the embodiment provided in the present application, the porosity of the covalent organic framework material is within the above range, and it has good adsorption properties for gases generated by the decomposition of ammonium salts and gases generated by the decomposition of organic amine cations in the perovskite material, thereby inhibiting the degradation of the perovskite material and improving the stability of the solar cell.

[0027] In some embodiments, the covalent organic framework material includes at least one of the following: COF-v, PyCOFCOF-Tz, COF-42, PI-COF-1, COF-366, GS-COF-2-COOH.

[0028] In the embodiments provided herein, the covalent organic framework material can adsorb the gas produced by the decomposition of the ammonium salt and the gas produced by the decomposition of the organic amine cation in the perovskite material. These two gases have at least partially the same composition. That is, in the covalent organic framework material system, the amount of gas with the same composition as the gas produced by the decomposition of the organic amine cation in the perovskite material increases, thereby making the decomposition reaction of the organic amine cation in the perovskite material close to the equilibrium state, thereby inhibiting the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and then improving the stability of the solar cell. At the same time, the above-mentioned materials are easy to purchase, which reduces the difficulty of preparing high-stability perovskite solar cells.

[0029] In some embodiments, the functional layer is located at the lower interface of the light absorbing layer.

[0030] In the embodiment provided in the present application, the covalent organic framework material can adsorb the gas produced by the decomposition of ammonium salts and the gas produced by the decomposition of organic amine cations in the perovskite material. The two gases have at least partially the same composition, that is, in the covalent organic framework material system, the amount of gas with the same composition as the gas produced by the decomposition of organic amine cations in the perovskite material increases, so that the decomposition reaction of the organic amine cations in the perovskite material is close to the equilibrium state, thereby inhibiting the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and then improving the stability of the solar cell.

[0031] In some embodiments, the thickness of the functional layer is less than or equal to 20 nm.

[0032] In the embodiment provided in the present application, the thickness of the functional layer is within the above-mentioned range, which can achieve defect passivation while regulating the crystallization of perovskite, and can adsorb gases generated by the decomposition of ammonium salts and the decomposition of organic amine cations in the perovskite material, thereby inhibiting the degradation of the perovskite material and facilitating the transfer of charges. Therefore, it not only improves the stability of the solar cell, but also maintains a good photoelectric conversion efficiency of the solar cell.

[0033] The present application provides a method for preparing a solar cell, comprising:

[0034] Providing a substrate structure, the substrate structure including a first charge transport layer;

[0035] Disposing a functional layer on the first charge transport layer, the functional layer comprising a covalent organic framework material and an ammonium salt;

[0036] A light absorbing layer is provided on the functional layer. The light absorbing layer includes a perovskite material. The cations of the perovskite material include organic amine cations.

[0037] The present application introduces a functional layer including a covalent organic framework material and an ammonium salt between the first charge transport layer and the light absorption layer. The covalent organic framework material can adsorb the gas generated by the decomposition of the ammonium salt and the gas generated by the decomposition of the organic amine cations in the perovskite material. The two gases have at least partially the same composition. That is, in the covalent organic framework material system, the amount of gas with the same composition as the gas generated by the decomposition of the organic amine cations in the perovskite material increases, so that the decomposition reaction of the organic amine cations in the perovskite material is close to the equilibrium state, thereby inhibiting the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and further improving the stability of the solar cell.

[0038] The present application provides a method for preparing a solar cell, wherein the step of providing a functional layer on a first charge transport layer comprises:

[0039] Providing a functional precursor liquid, placing the functional precursor liquid on the first charge transport layer, and performing a heat treatment to form a functional layer;

[0040] The functional precursor solution includes a covalent organic framework material, an ammonium salt and a solvent. The concentration of the covalent organic framework material in the functional precursor solution is 0.1 mg / L to 20 mg / L, the amount of the ammonium salt is 1% to 20% of the amount of the covalent organic framework material, and the solvent is a polar solvent.

[0041] In the technical solution of the embodiment of the present application, the functional layer is prepared by a solution method, and at the same time, the preparation method of the functional precursor solution is controlled, which is conducive to the preparation of large-area devices.

[0042] The present application provides an electrical device, including the above-mentioned solar cell or a solar cell prepared by the above-mentioned method for preparing a solar cell.

[0043] Since the device of the present application includes the solar cell provided by the present application, it has at least the same advantages as the solar cell.

[0044] The present application provides a power generation device, including the above-mentioned solar cell or a solar cell prepared by the above-mentioned method for preparing a solar cell.

[0045] Since the device of the present application includes the solar cell provided by the present application, it has at least the same advantages as the solar cell.

[0046] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0048] Figure 1 This is a schematic structural diagram of a solar cell according to some embodiments of the present application;

[0049] Figure 2 This is a schematic structural diagram of an electrical device according to some embodiments of the present application;

[0050] Figure 3 This is a schematic structural diagram of a power generation device according to some embodiments of the present application.

[0051] In the attached figure:

[0052] 11. Second electrode layer; 12. Second charge transport layer; 13. Light absorption layer; 14. Functional layer; 15. First charge transport layer; 16. First electrode layer; 100. Solar cell; 1000. Electricity-consuming device; 2000. Power generation device. DETAILED DESCRIPTION

[0053] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0055] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0056] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0057] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0058] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0059] Perovskite solar cells are currently a promising solar cell and a hot topic of research due to their outstanding advantages, including high photoelectric conversion efficiency, low cost, and simple fabrication. They can be used in lunar rovers, satellite panels, various sensors and detectors, as well as in civilian products such as wearable electronics and automotive power supplies. Perovskite solar cells are becoming a power source for consumer products in many ways. With the continuous expansion of perovskite solar cell applications and the flexible and foldable nature of perovskite solar cells, market demand is also growing.

[0060] The poor stability of existing perovskite solar cell devices has restricted the industrial development of perovskite solar cells.

[0061] In order to solve the above technical problems, the present application provides a solar cell 100. Figure 1 , the solar cell 100 comprises at least:

[0062] a first charge transport layer 15;

[0063] a light absorbing layer 13, the light absorbing layer 13 comprising a perovskite material, wherein cations of the perovskite material comprise organic amine cations; and

[0064] The functional layer 14 is located between the first charge transport layer 15 and the light absorption layer 13 . The functional layer 14 includes a covalent organic framework material and an ammonium salt.

[0065] The present application introduces a functional layer 14 including a covalent organic framework material and an ammonium salt between the first charge transport layer 15 and the light absorption layer 13 to regulate the crystallization of the perovskite while achieving defect passivation; at the same time, the covalent organic framework material can adsorb the gas generated by the decomposition of the ammonium salt and the gas generated by the decomposition of the organic amine cations in the perovskite material, and these two gases have at least partially the same composition, that is, in the covalent organic framework material system, the amount of gas with the same composition as the gas generated by the decomposition of the organic amine cations in the perovskite material increases, so that the decomposition reaction of the organic amine cations in the perovskite material is close to the equilibrium state, thereby inhibiting the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and then improving the stability of the solar cell.

[0066] In some embodiments, the cation of the perovskite material includes at least one of formamidine cations, methylamine cations, and guanidinium cations; and the ammonium salt includes an ammonium salt whose decomposition product contains at least one of methylamine, formamidine, guanidine, and ammonia.

[0067] The chemical formula of the perovskite material satisfies the molecular formula ABX3, where A is a monovalent cation with a larger radius, including organic amine cations: methylamine (CH3NH3 + ), carboxamidino (HC(NH2)2 + ), guanidine (C (NH2) 3 + ) etc.; B is a divalent metal cation with a smaller radius, including but not limited to the following materials: divalent metal cations such as lead ions (Pb 2+ ), tin ions (Sn 2+ ) etc.; X is a monovalent anion, including but not limited to the following materials: chloride ion (Cl - ), bromide ion (Br - ), iodide ion (I -) etc.; and the perovskite layer has a band gap of 1.20 eV to 2.30 eV and a thickness of 400 nm to 1000 nm. In the embodiments provided in the present application, when the cations of the perovskite material include organic amine cations, the covalent organic framework material can adsorb the gas produced by the decomposition of the ammonium salt and the gas produced by the decomposition of the organic amine cations in the perovskite material, and the two gases have at least partially the same composition, that is, in the covalent organic framework material system, the amount of gas with the same composition as the gas produced by the decomposition of the organic amine cations in the perovskite material increases, thereby making the decomposition reaction of the organic amine cations in the perovskite material close to the equilibrium state, thereby inhibiting the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and further improving the stability of the solar cell.

[0068] In some embodiments, the first charge transport layer 15 is a hole transport layer, and the functional layer 14 is located between the first charge transport layer 15 and the light absorbing layer 13, separating the hole transport layer and the perovskite material, thereby inhibiting the redox reaction between the A-site cations in the perovskite material and the hole transport layer, and further improving the stability of the perovskite material. For example, when the hole transport layer material is nickel oxide, the functional layer 14 inhibits the nickel ion (Ni 3+ ) and the redox reaction between the perovskite A-site cations.

[0069] In one embodiment, the cation of the ammonium salt includes at least one of a formamidinium cation, a methylamine cation, a guanidinium cation, and an ammonium cation. The gas generated by the decomposition of the ammonium salt and the gas generated by the decomposition of the organic amine cation in the perovskite material have at least partially the same composition. That is, in the covalent organic framework material system, the amount of gas with the same composition as the gas generated by the decomposition of the organic amine cation in the perovskite material increases, thereby bringing the decomposition reaction of the organic amine cation in the perovskite material close to equilibrium, thereby suppressing the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and further improving the stability of the solar cell.

[0070] In some embodiments, the ammonium salt comprises at least one of methylamine hydrohalide, formamidine hydrohalide, guanidine hydrohalide, ammonium carbonate, and ammonium bicarbonate. It is understood that hydrohalide includes but is not limited to hydroiodide, hydrofluoride, hydrochloride, and hydrobromide. Further optionally, the ammonium salt comprises any one of formamidine hydroiodide (FAI) and methylamine hydroiodide (MAI).

[0071] In some embodiments, the amount of the ammonium salt is 1% to 20% of the amount of the covalent organic framework material.

[0072] The amount of ammonium salt is 1% to 20% of the amount of the covalent organic framework material, and can be 1%, 5%, 7%, 8.5%, 10%, 11.2%, 14.65%, 15%, 19%, 20%, etc., or a range consisting of any two of the above values, for example, it can be 1% to 7%, 8.5% to 14.65%, 15% to 20%, etc.

[0073] In the embodiment provided in the present application, the amount of the ammonium salt is within the above range, which is beneficial to inhibiting the degradation of the perovskite material and the stability of the film layer, thereby improving the stability of the solar cell.

[0074] In some embodiments, the covalent organic framework material includes at least one of a N atom having a lone pair of electrons and a S atom having a lone pair of electrons.

[0075] In the embodiment provided in the present application, the covalent organic framework material is within the above-mentioned range, and the N atoms and S atoms containing lone pair electrons in the covalent organic framework material can be complexed with the uncoordinated lead ions in the perovskite material, thereby reducing the deep energy level defect concentration, being able to regulate the crystallization of the perovskite while achieving defect passivation, and improving the stability of the solar cell.

[0076] In some embodiments, the covalent organic framework material is a framework structure formed by connecting several A units and several B units, or a framework structure formed by connecting several A units, wherein the A unit includes a conjugated structure having a carboxyl group or an amine group, and the B unit includes any one of an alkyl chain, a chain structure containing a benzene ring, and a chain structure containing a heterocycle.

[0077] Covalent organic frameworks (COFs) are a class of materials with highly ordered structures, large pores, and controllable chemical functionality. In the above embodiment, the A unit is the basic building block of the COF, and specific functional groups such as carboxyl or amine groups on it impart specific chemical properties and functions to the material. The B unit connects the A units together to form the COF's backbone structure, and the B unit is relatively stable.

[0078] In the embodiments provided in the present application, the covalent organic framework material can regulate the crystallization of the perovskite while achieving defect passivation within the above-mentioned range, and can adsorb the gases generated by the decomposition of ammonium salts and the gases generated by the decomposition of organic amine cations in the perovskite material, thereby inhibiting the degradation of the perovskite material and improving the stability of the solar cell.

[0079] In one embodiment, unit A comprises the following structure:

[0080]

[0081]

[0082] At this time, covalent organic framework materials can regulate the crystallization of perovskite while achieving defect passivation and improving the stability of solar cells.

[0083] In some embodiments, the electrical conductivity of the covalent organic framework material is 10 -8 S m -1 ~10 -2 S m -1 .

[0084] In the embodiment provided in the present application, the electrical conductivity of the covalent organic framework material is within the above-mentioned range, and while being able to regulate the crystallization of perovskite, defect passivation is achieved. It is able to adsorb gases generated by the decomposition of ammonium salts and gases generated by the decomposition of organic amine cations in the perovskite material, inhibit the degradation of the perovskite material, and is also beneficial to the transmission of charges. Therefore, it not only improves the stability of the solar cell, but also maintains a good photoelectric conversion efficiency of the solar cell.

[0085] In some embodiments, the porosity of the covalent organic framework material is 50% to 90%.

[0086] In the embodiment provided in the present application, the porosity of the covalent organic framework material is within the above range, and it has good adsorption properties for gases generated by the decomposition of ammonium salts and gases generated by the decomposition of organic amine cations in the perovskite material, thereby inhibiting the degradation of the perovskite material and improving the stability of the solar cell.

[0087] In some embodiments, the covalent organic framework material includes at least one of the following: COF-v (CAS: 2065232-77-9), PyCOF (CAS: 2185790-08-1), COF-Tz (CAS: 1788078-55-6), COF-42 (CAS: 1314877-67-2), PI-COF-1 (CAS: 286831-92-3), COF-366 (CAS: 1381930-10-4), GS-COF-2-COOH.

[0088] The structural formula of GS-COF-2-COOH is:

[0089]

[0090] In the embodiments provided herein, the covalent organic framework material can adsorb the gas produced by the decomposition of the ammonium salt and the gas produced by the decomposition of the organic amine cation in the perovskite material. These two gases have at least partially the same composition. That is, in the covalent organic framework material system, the amount of gas with the same composition as the gas produced by the decomposition of the organic amine cation in the perovskite material increases, thereby making the decomposition reaction of the organic amine cation in the perovskite material close to the equilibrium state, thereby inhibiting the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and then improving the stability of the solar cell. At the same time, the above-mentioned materials are easy to purchase, which reduces the difficulty of preparing high-stability perovskite solar cells.

[0091] In some embodiments, the functional layer 14 is located at the lower interface of the light absorbing layer 13 .

[0092] In the embodiment provided in the present application, the covalent organic framework material can adsorb the gas produced by the decomposition of ammonium salts and the gas produced by the decomposition of organic amine cations in the perovskite material. The two gases have at least partially the same composition, that is, in the covalent organic framework material system, the amount of gas with the same composition as the gas produced by the decomposition of organic amine cations in the perovskite material increases, so that the decomposition reaction of the organic amine cations in the perovskite material is close to the equilibrium state, thereby inhibiting the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and then improving the stability of the solar cell.

[0093] In some embodiments, the thickness of the functional layer 14 is less than or equal to 20 nm.

[0094] The thickness of the functional layer 14 is less than or equal to 20 nm, and can be 0.1 nm, 1.2 nm, 3 nm, 5 nm, 7 nm, 10 nm, 14.5 nm, 15 nm, 16 nm, 17.5 nm, 20 nm, etc., or a range consisting of any two of the above values, for example, it can be 0.1 nm to 3 nm, 5 nm to 14.5 nm, 16 nm to 17.5 nm, 17.5 nm to 20 nm, etc.

[0095] In the embodiment provided in the present application, the thickness of the functional layer 14 is within the above-mentioned range, which can achieve defect passivation while regulating the crystallization of the perovskite, and can adsorb the gas generated by the decomposition of the ammonium salt and the gas generated by the decomposition of the organic amine cation in the perovskite material, thereby inhibiting the degradation of the perovskite material and facilitating the transmission of charges. Therefore, it not only improves the stability of the solar cell, but also maintains the good photoelectric conversion efficiency of the solar cell.

[0096] The present application provides a method for preparing a solar cell 100, comprising:

[0097] Providing a substrate structure, the substrate structure including a first charge transport layer 15;

[0098] A functional layer 14 is provided on the first charge transport layer 15, wherein the functional layer 14 comprises a covalent organic framework material and an ammonium salt;

[0099] The light absorbing layer 13 is provided on the functional layer 14 . The light absorbing layer 13 includes a perovskite material, and cations of the perovskite material include organic amine cations.

[0100] The present application introduces a functional layer 14 including a covalent organic framework material and an ammonium salt between the first charge transport layer 15 and the light absorption layer 13. The covalent organic framework material can adsorb the gas generated by the decomposition of the ammonium salt and the gas generated by the decomposition of the organic amine cations in the perovskite material. The two gases have at least partially the same composition. That is, in the covalent organic framework material system, the amount of gas with the same composition as the gas generated by the decomposition of the organic amine cations in the perovskite material increases, so that the decomposition reaction of the organic amine cations in the perovskite material is close to the equilibrium state, thereby inhibiting the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and then improving the stability of the solar cell.

[0101] The present application provides a method for preparing a solar cell 100, wherein the step of providing a functional layer 14 on a first charge transport layer 15 comprises:

[0102] Providing a functional precursor solution, placing the functional precursor solution on the first charge transport layer 15, and performing a heat treatment to form a functional layer 14;

[0103] The functional precursor solution includes a covalent organic framework material, an ammonium salt and a solvent. The concentration of the covalent organic framework material in the functional precursor solution is 0.1 mg / L to 20 mg / L, the amount of the ammonium salt is 1% to 20% of the amount of the covalent organic framework material, and the solvent is a polar solvent.

[0104] The concentration of the covalent organic framework material in the functional precursor solution is 0.1 mg / L to 20 mg / L, which can be 0.1 mg / L, 1.4 mg / L, 4.5 mg / L, 6 mg / L, 10 mg / L, 12.65 mg / L, 15 mg / L, 17 mg / L, 18.67 mg / L, 20 mg / L, etc., or a range consisting of any two of the above values, for example, it can be 1.4 mg / L to 6 mg / L, 10 mg / L to 12.65 mg / L, 15 mg / L to 18.67 mg / L, etc.

[0105] The amount of ammonium salt is 1% to 20% of the amount of the covalent organic framework material, and can be 1%, 5%, 7%, 8.5%, 10%, 11.2%, 14.65%, 15%, 19%, 20%, etc., or a range consisting of any two of the above values, for example, it can be 1% to 7%, 8.5% to 14.65%, 15% to 20%, etc.

[0106] In the technical solution of the embodiment of the present application, the functional layer 14 is prepared by a solution method. At the same time, the preparation method of the functional precursor solution is controlled, which is conducive to the preparation of large-area devices.

[0107] See Figure 1 In some embodiments, the solar cell 100 may include a first electrode layer 16, a first charge transport layer 15, a functional layer 14, a light absorption layer 13, a second charge transport layer 12, and a second electrode layer 11, which are arranged in sequence. In this embodiment, the solar cell 100 has a trans structure, that is, the first charge transport layer 15 in the solar cell 100 is a hole transport layer, and the second charge transport layer 12 is an electron transport layer; in other embodiments, the solar cell 100 may also have a regular structure, that is, the first charge transport layer 15 in the solar cell 100 is an electron transport layer, and the second charge transport layer 12 is a hole transport layer.

[0108] The first electrode layer 16 includes, but is not limited to, the following materials: fluorine-doped tin oxide (FTO), tungsten-doped indium oxide (IWO), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), indium zinc oxide (IZO), etc. The thickness of the first electrode layer 10 is 10 nm to 1000 nm, and can be 10 nm, 55 nm, 103 nm, 358 nm, 480 nm, 650 nm, 890 nm, 980 nm, 1000 nm, etc., or a range consisting of any two of the above values, for example, 10 nm to 103 nm, 55 nm to 358 nm, 103 nm to 480 nm, 480 nm to 890 nm, 55 nm to 890 nm, 358 nm to 980 nm, etc.

[0109] The first charge transport layer 15 may be a hole transport layer, which is made of at least one of the following materials and their derivatives and materials obtained by doping or passivation: BTPA series hole transport materials, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), poly-3-hexylthiophene (P3HT), triphenylamine with triptycene as the core (H101), 3,4-ethylenedioxythiophene-methoxytriphenylamine (EDOT-OMeTPA), N-(4-phenylamino)carbazole-spirobifluorene (CzPAF-SBF), poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), polythiophene, nickel oxide (NiO x ), molybdenum oxide (MoO3), cuprous iodide (CuI), cuprous oxide (Cu2O), etc.

[0110] The light absorbing layer 13 includes a perovskite material. The chemical formula of the perovskite material satisfies the molecular formula ABX3, wherein A is a monovalent cation with a large radius, including an organic amine cation: methylamine (CH3NH3 + ), carboxamidino (HC(NH2)2 + ) etc.; B is a divalent metal cation with a smaller radius, including but not limited to the following materials: divalent metal cations such as lead ions (Pb 2+ ), tin ions (Sn 2+ ) etc.; X is a monovalent anion, including but not limited to the following materials: chloride ion (Cl - ), bromide ion (Br - ), iodide ion (I - ) etc.; the band gap of the perovskite layer 13 is 1.20 eV to 2.30 eV; the thickness of the perovskite layer 13 is between 400 nm and 1000 nm, and can be 400 nm, 468 nm, 632 nm, 744 nm, 834 nm, 970 nm, 1000 nm, etc., or a range consisting of any two of the above values, for example, it can be 400 nm to 970 nm, 468 nm to 632 nm, 468 nm to 834 nm, 632 nm to 834 nm, 632 nm to 970 nm, etc.

[0111] The second charge transport layer 12 may be an electron transport layer, and the electron transport layer material is at least one of the following materials and their derivatives or doped and passivated materials: [6,6]-phenyl C 61 Methyl butyrate (PC 61 BM), [6,6]-phenyl C 71 Methyl butyrate (PC 71BM), fullerene and its derivatives, tin dioxide (SnO2), zinc oxide (ZnO), etc. The thickness of the electron transport layer is 5 nm to 50 nm, 5 nm, 8 nm, 10 nm, 13 nm, 15 nm, 20 nm, 21.5 nm, 23.3 nm, 25 nm, 30 nm, 32 nm, 34.4 nm, 38 nm, 40 nm, 45 nm, 48.6 nm, 50 nm, etc., or a range consisting of any two of the above values, for example, 10 nm to 13 nm, 20 nm to 21.5 nm, 25 nm to 30 nm, 32 nm to 34.4 nm, 48.6 nm to 50 nm, etc.

[0112] The second electrode layer 11 may be made of an organic, inorganic, or organic-inorganic hybrid conductive material, including but not limited to the following materials: silver (Ag), copper (Cu), carbon (C), gold (Au), aluminum (Al), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), indium zinc oxide (IZO), etc. The thickness of the second electrode layer 15 is 10 nm to 1000 nm, and may be 10 nm, 220 nm, 335 nm, 380 nm, 470 nm, 660 nm, 880 nm, 970 nm, 1000 nm, etc., or a range consisting of any two of the above values, for example, 10 nm to 970 nm, 220 nm to 380 nm, 335 nm to 660 nm, 470 nm to 880 nm, 335 nm to 970 nm, 470 nm to 1000 nm, etc.

[0113] See Figure 2 The present application provides an electrical device 1000, including the above-mentioned solar cell 100 or a solar cell prepared by the above-mentioned solar cell preparation method.

[0114] In the present application, the solar cell 100 serves as a power source for the electrical device 1000; alternatively, the solar cell 100 can serve as an energy storage unit for the electrical device 1000. For example, the electrical device 1000 can be a lighting element, a display element, or a car.

[0115] See Figure 3 The present application further provides a power generation device 2000, comprising the aforementioned solar cell 100 or a solar cell prepared by the aforementioned solar cell preparation method. The power generation device 2000 can be used for generating electricity and comprises at least the solar cell 100.

[0116] In order to make the technical problems, technical solutions and beneficial effects solved by the embodiments of the present application clearer, the following will be further described in detail with reference to the embodiments and drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0117] The solar cell 100 of the present application introduces a functional layer 14 comprising a covalent organic framework material and an ammonium salt between the first charge transport layer 15 and the light absorption layer 13 as described above, thereby regulating the crystallization of the perovskite while achieving defect passivation. Furthermore, the covalent organic framework material can adsorb gases produced by the decomposition of the ammonium salt and gases produced by the decomposition of the organic amine cations in the perovskite material. These two gases have at least partially the same composition. That is, in the covalent organic framework material system, the amount of gas with the same composition as the gas produced by the decomposition of the organic amine cations in the perovskite material increases, thereby bringing the decomposition reaction of the organic amine cations in the perovskite material close to equilibrium, thereby inhibiting the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material and, in turn, the stability of the solar cell. This novel solar cell 100 is applicable to both regular and inverted solar cells.

[0118] The formal method for preparing the novel solar cell 100 includes the following steps:

[0119] Step 1: etching and cleaning a transparent glass substrate, and drying it for later use, wherein the transparent conductive glass substrate has a first electrode layer 16;

[0120] Step 2: preparing a first charge transport layer 15 on the transparent conductive glass electrode for standby use, wherein the first charge transport layer 15 is an electron transport layer;

[0121] Step 3: preparing a functional layer 14 on the first charge transport layer 15 for standby use;

[0122] Step 4: Prepare a perovskite light absorbing layer 13 on the functional layer 14 for later use;

[0123] Step 5: preparing a second charge transport layer 12 on the perovskite layer 13 for standby use, wherein the second charge transport layer 12 is a hole transport layer;

[0124] Step 6: Prepare the second electrode layer 11 on the second charge transport layer 12 and perform edge cleaning test.

[0125] The method for preparing the novel inverted solar cell 100 comprises the following steps:

[0126] Step 1: etching and cleaning a transparent glass substrate, and drying it for later use, wherein the transparent conductive glass substrate has a first electrode layer 16;

[0127] Step 2: preparing a first charge transport layer 15 on the transparent conductive glass electrode for standby use, wherein the first charge transport layer 15 is a hole transport layer;

[0128] Step 3: preparing a functional layer 14 on the first charge transport layer 15 for standby use;

[0129] Step 4: Prepare a light absorbing layer 13 on the functional layer 14 for later use;

[0130] Step 5: preparing a second charge transport layer 12 on the light absorption layer 13 for standby use, wherein the second charge transport layer 12 is an electron transport layer;

[0131] Step 6: Prepare the second electrode layer 11 on the second charge transport layer 12 and perform edge cleaning test. The following examples illustrate the preparation methods of the new solar cell 100 in both the formal and inverted forms:

[0132] Example 1:

[0133] (1) Preparation of the first electrode layer: Specifications: 2.0 × 2.0 cm 2 The FTO conductive glass was removed by laser etching at both ends to remove 0.35 cm of FTO to expose the glass substrate; the etched FTO conductive glass was ultrasonically cleaned several times with water, acetone, and isopropyl alcohol, and then dried with nitrogen for later use;

[0134] (2) Preparation of the first charge transport layer: A SnO2 colloidal solution was spin-coated at a rate of 4000 rpm / s on a UV-ozone treated FTO substrate and annealed on a hot plate at 150°C for 10 minutes to form the first charge transport layer. The thickness of the first charge transport layer was 20 nm.

[0135] (3) Preparation of the functional layer: 100 μL of an isopropanol solution of PyCOF doped with 2% FAI (formamidine hydroiodide) was spin-coated at 4000 rpm onto the surface of the first charge transport layer. The PyCOF concentration was 5 mg / mL and the layer was annealed at 100°C for 10 min to obtain a functional layer with a thickness of approximately 15 nm.

[0136] (4) Preparation of perovskite layer: The perovskite light absorption layer was prepared by a one-step method. The perovskite precursor solution was spin-coated on the prepared functional layer at a speed of 4000 rpm for 40 seconds. 300 μL of anti-solvent was added about 10 seconds after the start of spin coating. The film was then placed on a hot plate and annealed at 100°C for 60 minutes to obtain a perovskite layer with a thickness of 500 nm (FA 0.98 MA0.02 ) 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 )3;

[0137] (5) Preparation of the second charge transport layer: Prepare a 72 mg / ml chlorobenzene solution of the hole transport material Spiro-OMeTAD, stir to completely dissolve it, and take 100 μL and spin-coat it on the surface of the perovskite layer at a speed of 4000 rpm to obtain a second charge transport layer with a thickness of about 170 nm;

[0138] (6) Preparation of the second electrode layer: Place the film with the second charge transport layer into the evaporation apparatus and wait until the evaporation vacuum reaches 5×10 -4 Pa, and 80nm of Au metal back electrode was evaporated at a rate of 0.1A / s.

[0139] The solar cell obtained through the above steps is marked as cell 1.

[0140] Example 2:

[0141] (1) Preparation of the first electrode layer: Specifications: 2.0 × 2.0 cm 2 The fluorine-doped tin oxide (FTO) conductive glass was prepared by laser etching, and 0.35 cm of FTO was removed from each end to expose the glass substrate. The etched FTO conductive glass was ultrasonically cleaned several times with water, acetone, and isopropyl alcohol, and then dried with nitrogen.

[0142] (2) Preparation of the first charge transport layer: FTO was treated with UV ozone, and then a NiO layer with a thickness of about 30 nm was magnetron sputtered. x , annealing at 300°C for 60 min to obtain a first charge transport layer;

[0143] (3) Preparation of the functional layer: 100 μL of an isopropanol solution of 2% FAI-doped PyCOF was spin-coated at 4000 rpm onto the surface of the first charge transport layer. The PyCOF concentration was 5 mg / mL and the layer was annealed at 100°C for 10 min to obtain a functional layer with a thickness of approximately 15 nm.

[0144] (4) Preparation of perovskite layer: The perovskite light absorption layer was prepared by a one-step method. The perovskite precursor solution was spin-coated on the prepared UV absorption layer at a speed of 4000 rpm for 40 seconds. 300 μL of anti-solvent was added about 10 seconds after the start of spin coating. The film was then placed on a hot plate and annealed at 100°C for 60 minutes to obtain a perovskite layer with a thickness of 500 nm (FA 0.98 MA 0.02 ) 0.95 Cs 0.05Pb(I 0.98 Br 0.02 )3;

[0145] (5) Preparation of the second charge transport layer: Place the film with the perovskite light absorbing layer into the evaporation apparatus and wait until the evaporation vacuum reaches 5×10 -4 Pa below, 30nm electron transport layer C was evaporated at a rate of 0.05A / s 60 ;

[0146] (6) Preparation of the second electrode layer: Place the film with the second charge transport layer into the evaporation apparatus and wait until the evaporation vacuum reaches 5×10 -4 Pa, and 80nm of metal back electrode Ag was evaporated at a rate of 0.1A / s.

[0147] The solar cell obtained through the above steps is labeled as cell 2.

[0148] Example 3:

[0149] Except for step (3), the remaining steps are the same as those in Example 2.

[0150] (3) Preparation of the functional layer: 100 μL of an isopropanol solution of 5% FAI-doped PyCOF was spin-coated at 4000 rpm onto the surface of the first charge transport layer. The PyCOF concentration was 5 mg / mL and the layer was annealed at 100°C for 10 min to obtain a functional layer with a thickness of approximately 15 nm.

[0151] The perovskite solar cell obtained by the above steps is marked as cell 3.

[0152] Example 4:

[0153] Except for step (3), the remaining steps are the same as those in Example 2.

[0154] (3) Preparation of the functional layer: 100 μL of an isopropanol solution of PyCOF doped with 10% FAI was spin-coated at 4000 rpm onto the surface of the first charge transport layer. The PyCOF concentration was 5 mg / mL and the layer was annealed at 100°C for 10 min to obtain a functional layer with a thickness of approximately 15 nm.

[0155] The perovskite solar cell obtained through the above steps is labeled as cell 4.

[0156] Example 5:

[0157] Except for step (3), the remaining steps are the same as those in Example 2.

[0158] (3) Preparation of the functional layer: 100 μL of an isopropanol solution of COF-Tz doped with 2% MAI (methylamine hydroiodide) was spin-coated at 4000 rpm onto the surface of the first charge transport layer. The COF-Tz concentration was 5 mg / mL and the layer was annealed at 100°C for 10 min to obtain a functional layer with a thickness of approximately 15 nm.

[0159] The perovskite solar cell obtained through the above steps is labeled as cell 5.

[0160] Comparative Example 1 is the same as Example 1, and Comparative Example 2 is the same as Example 2, except that the solar cell does not include a covalent organic framework material and an ammonium salt functional layer. Cells 6 and 7 are obtained above.

[0161] Comparative Examples 3 and 5 are the same as Example 1, except that the functional layer of the solar cell only includes the covalent organic framework material. Cells 8 and 10 are obtained as described above.

[0162] Comparative Examples 4 and 6 are the same as Example 2, except that the functional layer of the solar cell only includes ammonium salt. Cells 9 and 11 are obtained above.

[0163] The battery devices 1 to 11 obtained in the above Examples 1 to 5 and Comparative Examples 1 to 6 were subjected to battery performance tests, and Table 1 was obtained.

[0164] Test method:

[0165] 1. Photovoltaic conversion efficiency of perovskite solar cells

[0166] Using Keithley 2400SMU, AM 1.5G solar irradiation at 100mW / cm 2 The battery performance is tested under a light source, and the photoelectric conversion efficiency is calculated as follows:

[0167] PCE

[0168] =Pout / Popt

[0169] =Voc×Jsc×(Vmpp×Jmpp) / (Voc×Jsc)

[0170] =Voc×Jsc×FF

[0171] Among them, Pout, Popt, Vmpp, Jmpp, Voc and Jsc are the battery operating output power, incident light power, battery maximum power point voltage, battery maximum power point current, open circuit voltage and short circuit current respectively.

[0172] 2. Stability test

[0173] The perovskite solar cell was placed on a hot plate at 75°C for heating, and its photoelectric conversion efficiency was tracked as it changed with aging time. The time required for its photoelectric conversion efficiency to decay to 80% of the initial efficiency was recorded as T80. The size of this parameter indicates the light stability of the perovskite solar cell.

[0174] Table 1 Battery performance test

[0175] Device Serial number <![CDATA[V OC (V)]]> FF(%) <![CDATA[Jsc(mA / cm 2 )]]> PCE (%) T80(h) Battery 1 Example 1 1.11 82.37 24.72 22.51 800 Battery 2 Example 2 1.10 83.29 24.47 22.46 790 Battery 3 Example 3 1.10 81.01 24.48 21.81 765 Battery 4 Example 4 1.06 81.21 24.28 20.91 680 Battery 5 Example 5 1.11 82.17 24.62 22.35 806 Battery 6 Comparative Example 1 0.95 81.77 24.25 18.74 530 Battery 7 Comparative Example 2 0.95 82.34 24.41 19.08 550 Battery 8 Comparative Example 3 1.02 76.75 24.77 19.46 600 Battery 9 Comparative Example 4 1.03 76.80 24.89 19.61 630 Battery 10 Comparative Example 5 1.02 76.26 24.83 19.39 580 Battery 11 Comparative Example 6 1.00 79.48 24.26 19.41 610

[0176] It can be seen from the relevant data in Table 1 that the solar cells of Examples 1 to 5 all added a functional layer including a covalent organic framework material and an ammonium salt. Under the same light source, the photoelectric conversion efficiency of the device was higher than that of Comparative Examples 1 to 6, and the time required for the photoelectric conversion efficiency to decay to 80% of the initial efficiency was also higher than that of Comparative Examples 1 to 6. This shows that the present application regulates the crystallization of perovskite while achieving defect passivation by introducing a functional layer including a covalent organic framework material and an ammonium salt between the first charge transport layer and the light absorption layer; at the same time, the covalent organic framework material can adsorb the gas generated by the decomposition of the ammonium salt and the gas generated by the decomposition of the organic amine cation in the perovskite material, and the two gases have at least partially the same composition, that is, in the covalent organic framework material system, the amount of gas with the same composition as the gas generated by the decomposition of the organic amine cation in the perovskite material increases, so that the decomposition reaction of the organic amine cation in the perovskite material is close to the equilibrium state, thereby inhibiting the decomposition reaction of the perovskite material, thereby improving the stability of the perovskite material, and further improving the stability of the solar cell.

[0177] The above description is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A solar cell, characterized in that: At least: a first charge transport layer; a light absorbing layer, the light absorbing layer comprising a perovskite material, wherein cations of the perovskite material comprise organic amine cations; and A functional layer is located between the first charge transport layer and the light absorption layer, and the functional layer includes a covalent organic framework material and an ammonium salt.

2. The solar cell according to claim 1, wherein The cation of the perovskite material includes at least one of a formamidinium cation, a methylamine cation and a guanidinium cation; The ammonium salt includes an ammonium salt containing at least one of methylamine, formamidine, guanidine and ammonia in the decomposition product.

3. The solar cell according to claim 1 or 2, wherein: The cation of the ammonium salt includes at least one of a formamidinium cation, a methylamine cation, a guanidinium cation, and an ammonium cation.

4. The solar cell according to claim 3, wherein The ammonium salt includes at least one of methylamine hydrohalide, formamidine hydrohalide, guanidine hydrohalide, ammonium carbonate, and ammonium bicarbonate.

5. The solar cell according to any one of claims 1 to 4, wherein The amount of the ammonium salt is 1% to 20% of the amount of the covalent organic framework material.

6. The solar cell according to any one of claims 1 to 5, wherein The covalent organic framework material includes at least one of a nitrogen atom having a lone pair of electrons and a sulfur atom having a lone pair of electrons.

7. The solar cell according to any one of claims 1 to 6, wherein: The covalent organic framework material includes a framework structure formed by connecting several A units and several B units, or a framework structure formed by connecting several A units, wherein the A unit includes a conjugated structure having a carboxyl group or an amine group, and the B unit includes any one of an alkyl chain, a chain structure containing a benzene ring, and a chain structure containing a heterocycle.

8. The solar cell according to claim 7, wherein The A unit includes the following structure:

9. The solar cell according to any one of claims 1 to 8, wherein The electrical conductivity of the covalent organic framework material is 10 -8 Sm -1 ~10 -2 Sm -1 .

10. The solar cell according to any one of claims 1 to 9, wherein The porosity of the covalent organic framework material is 50% to 90%.

11. The solar cell according to any one of claims 1 to 10, wherein: The covalent organic framework material includes at least one of the following: COF-v, PyCOF, COF-Tz, COF-42, PI-COF-1, COF-366, and GS-COF-2-COOH.

12. The solar cell according to any one of claims 1 to 11, wherein The functional layer is located at the lower interface of the light absorbing layer.

13. The solar cell according to any one of claims 1 to 12, wherein: The thickness of the functional layer is less than or equal to 20 nm.

14. A method for preparing a solar cell, characterized in that: At least: Providing a substrate structure, the substrate structure comprising a first charge transport layer; Disposing a functional layer on the first charge transport layer, wherein the functional layer comprises a covalent organic framework material and an ammonium salt; A light absorbing layer is provided on the functional layer. The light absorbing layer comprises a perovskite material. The cations of the perovskite material comprise organic amine cations.

15. The method for preparing a solar cell according to claim 14, wherein: The step of providing a functional layer on the first charge transport layer comprises: Providing a functional precursor liquid, placing the functional precursor liquid on the first charge transport layer, and performing a heat treatment to form the functional layer; The functional precursor solution comprises the covalent organic framework material, the ammonium salt and a solvent. The concentration of the covalent organic framework material in the functional precursor solution is 0.1 mg / L to 20 mg / L, the amount of the ammonium salt is 1% to 20% of the amount of the covalent organic framework material, and the solvent is a polar solvent.

16. An electrical device, characterized in that: A solar cell comprising the solar cell according to any one of claims 1 to 13 or a solar cell prepared by the method for preparing a solar cell according to claim 14 or 15.

17. A power generation device, characterized in that: A solar cell comprising the solar cell according to any one of claims 1 to 13 or a solar cell prepared by the method for preparing a solar cell according to claim 14 or 15.

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