Tin-based perovskite solar cell, preparation method and photoelectric device

Abstract

The invention relates to a tin-based perovskite solar cell, a preparation method and a photoelectric device. The tin-based perovskite solar cell comprises a conductive substrate layer, an electron transport layer, an interface layer, a tin-based perovskite film layer, a hole transport layer and an electrode layer which are stacked. The interface layer contains a covalent organic framework material. The covalent organic framework material can generate electron hole pairs under an illumination condition, electrons in a conduction band are migrated to the surface of perovskite, and oxidation of Sn < 2 + > can be inhibited; the covalent organic framework material contains carbonyl, amino and other passivating groups which are beneficial to passivating metal defects on the surface of the tin-based perovskite film layer. Therefore, the tin-based perovskite solar cell provided by the invention has relatively high cell performance.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, and relates to a tin-based perovskite solar cell, its preparation method, and optoelectronic devices. Background Technology

[0002] With the continuous development of human society, the demand for energy is constantly increasing. Traditional energy sources such as oil, natural gas, and coal are all non-renewable energy sources. Not only are their reserves constantly decreasing, but their use also causes significant environmental pollution. Therefore, vigorously developing renewable, green, and clean energy is particularly urgent and important. Among them, solar energy has outstanding advantages: it is inexhaustible and does not harm the environment. Related application research has received increasing attention, and developing clean, pollution-free solar energy with huge reserves has become a hot topic of research for scientists.

[0003] Organic-inorganic halide perovskite materials have attracted widespread attention in the photovoltaic field due to their excellent photoelectric properties. However, the heavy metal lead contained in these materials is harmful to the environment and human health, which seriously hinders their commercialization. Tin, with its similar outer electron structure and ionic radius to lead, can form the same type of three-dimensional perovskite structure and possesses a more ideal optical band gap. It is the most promising material to replace lead-based perovskites and is expected to achieve better photovoltaic performance.

[0004] Currently, tin-based perovskite solar cells have achieved recorded efficiencies exceeding 14%. However, research on tin-based perovskite solar cells still faces many significant challenges. On one hand, tin-based perovskite materials are highly susceptible to oxidation, leading to the generation of Sn vacancies, which results in severe nonradiative recombination losses and voltage drops. On the other hand, the Ig in the material... - Furthermore, the organic cations at the A-site are easily volatilized during annealing, making the crystallization process of tin-based perovskite films more difficult to control, resulting in relatively poor film morphology and a tendency to form disordered grains, leading to a large number of three-dimensional defects. These defects facilitate the corrosion of oxygen and moisture, significantly reducing the performance and stability of the device.

[0005] Therefore, there is a need to provide a tin-based perovskite solar cell, its fabrication method, and an optoelectronic device that improves performance and stability. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a tin-based perovskite solar cell, its fabrication method, and an optoelectronic device. This tin-based perovskite solar cell, through the provision of an interface layer containing a covalent organic framework material, can effectively suppress Sn in the tin-based perovskite film. 2+ The oxidation process can passivate surface metal defects, enabling tin-based perovskite solar cells to have high cell performance.

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

[0008] In a first aspect, the present invention provides a tin-based perovskite solar cell, the tin-based perovskite solar cell comprising a conductive substrate layer, an electron transport layer, an interface layer, a tin-based perovskite film layer, a hole transport layer and an electrode layer stacked together.

[0009] The interface layer contains a covalent organic framework material, and the structural formula of the covalent organic framework material is as follows:

[0010] ;

[0011] The dashed lines represent sites that connect to another unit, and n is an integer from 0 to 9, such as 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9.

[0012] The tin-based perovskite solar cell provided by this invention has an interface layer between the electron transport layer and the tin-based perovskite film layer. The covalent organic framework material in the interface layer can generate electron-hole pairs under illumination, wherein electrons in the conduction band migrate to the perovskite surface, which can suppress Sn. 2+ The oxidation of the tin-based perovskite film is mitigated by the presence of carbonyl and amino passivating groups in the covalent organic framework material, which are beneficial for passivating metal defects on the surface of the tin-based perovskite film. Therefore, the tin-based perovskite solar cell provided by this invention has high battery performance.

[0013] In some embodiments, the method for preparing the covalent organic framework material includes:

[0014] 1,3,6,8-tetra(4-carboxyphenyl)pyrene and the co-reactant were mixed in a mixed solvent and reacted in a sealed environment at 110℃~130℃ for 60h~80h; the solid product obtained from the reaction was washed with an organic solvent and dried under vacuum to obtain the covalent organic framework material.

[0015] The mixed solvent comprises m-xylene, 1,4-dioxane, and acetic acid; the volume ratio of m-xylene to acetic acid is 4:1 to 6:1; the volume ratio of 1,4-dioxane to acetic acid is 4:1 to 6:1; and the concentration of acetic acid is 5 mol / L to 7 mol / L.

[0016] The structural formula of the co-reactant is:

[0017] ;

[0018] Where n is an integer from 0 to 9.

[0019] In some embodiments, the thickness of the interface layer is 20 nm to 100 nm.

[0020] In some embodiments, the thickness of the tin-based perovskite film is 100 nm to 400 nm.

[0021] In some embodiments, the tin-based perovskite material of the tin-based perovskite film has the general formula ABX3, wherein A includes CH3NH3. + CH(NH2)2 + Cs + or Rb + B includes any one or at least two of the following, where B includes Sn. 2+ or Sn 2+ With Pb 2+ The combination of X includes Cl - ,Br - or I - Any one or at least two of them.

[0022] In some embodiments, the conductive substrate layer is made of ITO conductive glass and / or FTO conductive glass.

[0023] In some embodiments, the material of the electron transport layer includes C. 60 The combination of any one or at least two of the following: [6,6]-phenyl-C61-butyrate, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, TiO2, SnO2, ZnO, or ZnO-ZnS.

[0024] In some embodiments, the hole transport layer is made of any one or a combination of at least two of the following: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, 4-butyl-N,N-diphenylaniline homopolymer, polyvinylcarbazole, nickel oxide, CuI, or CuSCN.

[0025] In some embodiments, the electrode layer is made of any one or a combination of at least two of Al, Au, Ag, or carbon.

[0026] Secondly, the present invention provides a method for preparing a tin-based perovskite solar cell, the method comprising the following steps:

[0027] A conductive substrate layer, an electron transport layer, an interface layer, a tin-based perovskite film layer, a hole transport layer, and an electrode layer are sequentially stacked to obtain the tin-based perovskite solar cell described in the first aspect.

[0028] Setting the interface layer includes: coating a covalent organic framework material solution onto the surface of the electron transport layer, followed by annealing to obtain the interface layer.

[0029] In some embodiments, the concentration of the covalent organic framework material in the solution is 1 mg / mL to 5 mg / mL.

[0030] In some embodiments, the solvent in the covalent organic framework material solution includes any one or a combination of at least two of water, ethanol, methanol, or acetonitrile.

[0031] In some embodiments, the annealing temperature is 110°C to 130°C.

[0032] In some embodiments, the annealing time is 10 min to 20 min.

[0033] In some embodiments, the method for setting the tin-based perovskite film layer includes: preparing a perovskite precursor solution containing tin-based perovskite material, coating it on the surface of the interface layer, and heating it to obtain the tin-based perovskite film layer.

[0034] In some embodiments, the solvent of the perovskite precursor solution includes any one or a combination of at least two of N,N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolinone, dimethylacetamide, N,N-dimethylpropenylurea, acetonitrile, or 2-mercaptoethanol.

[0035] Thirdly, the present invention provides an optoelectronic device, the optoelectronic device comprising the tin-based perovskite solar cell described in the first aspect, or the tin-based perovskite solar cell prepared by the preparation method described in the second aspect.

[0036] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The tin-based perovskite solar cell provided by this invention has an interface layer between the electron transport layer and the tin-based perovskite film layer. The covalent organic framework material in the interface layer can generate electron-hole pairs under illumination, wherein electrons in the conduction band migrate to the perovskite surface, which can suppress Sn. 2+ The oxidation of the tin-based perovskite film is mitigated by the presence of carbonyl and amino passivating groups in the covalent organic framework material, which are beneficial for passivating metal defects on the surface of the tin-based perovskite film. Therefore, the tin-based perovskite solar cell provided by this invention has high battery performance. Attached Figure Description

[0039] Figure 1 The ultraviolet spectra of the tin-based perovskite films in Example 1 and Comparative Example 1 are shown.

[0040] Figure 2 The fluorescence spectra of the tin-based perovskite films in Example 1 and Comparative Example 1 are shown. Detailed Implementation

[0041] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0042] The "range" disclosed in this invention can be defined in the form of 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 the specific range. This type of range definition can include or exclude endpoints; any endpoint can be independently included or excluded, and they can be arbitrarily combined, meaning 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 specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, unless otherwise stated, the numerical range "a~b" 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" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0043] In this invention, "a combination of at least two" refers to a quantity greater than or equal to two, unless otherwise specified. For example, "any combination of one or at least two" means one or more or more items. It can be understood that when referring to "a combination of at least two," it refers to any suitable combination of multiple items, that is, a combination of "at least two" items carried out in a manner that does not conflict with and enables the implementation of this invention.

[0044] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0045] The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0046] Those skilled in the art will understand that the order in which the steps are written in the methods of the various embodiments does not imply a strict execution order. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means 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), meaning that step (c) can 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.

[0047] In this invention, open-ended technical features or solutions described using terms such as "comprising" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or exclude additional members. This can be considered as providing both technical features or solutions where "A is composed of a1, a2, and a3" or "A is selected from a1, a2, and a3," and technical features or solutions where "A includes not only a1, a2, and a3, but also other members."

[0048] In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a group consisting of A, B, and "a combination of A and B". "Containing A and / or B" can mean "containing A, containing B, and containing A and B", or "containing A, containing B, or containing A and B", and can be appropriately understood according to the context.

[0049] In this invention, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0050] In this invention, "optional" means that something is optional, that is, it refers to either "with" or "without". If there are multiple "optional" options in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, then each "optional" option is independent.

[0051] In a first aspect, the present invention provides a tin-based perovskite solar cell, the tin-based perovskite solar cell comprising a conductive substrate layer, an electron transport layer, an interface layer, a tin-based perovskite film layer, a hole transport layer and an electrode layer stacked together.

[0052] The interface layer contains a covalent organic framework material, and the structural formula of the covalent organic framework material is as follows:

[0053] ;

[0054] The dashed lines represent sites that connect to another unit, and n is an integer from 0 to 9, such as 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9.

[0055] The tin-based perovskite solar cell provided by this invention has an interface layer between the electron transport layer and the tin-based perovskite film layer. The covalent organic framework material in the interface layer can generate electron-hole pairs under illumination, wherein electrons in the conduction band migrate to the perovskite surface, which can suppress Sn. 2+ The oxidation of the tin-based perovskite film is mitigated by the presence of carbonyl and amino passivating groups in the covalent organic framework material, which are beneficial for passivating metal defects on the surface of the tin-based perovskite film. Therefore, the tin-based perovskite solar cell provided by this invention has high battery performance.

[0056] In some embodiments, the method for preparing the covalent organic framework material includes:

[0057] 1,3,6,8-tetra(4-carboxyphenyl)pyrene and the co-reactant were mixed in a mixed solvent and reacted in a sealed environment at 110℃~130℃ for 60h~80h; the solid product obtained from the reaction was washed with an organic solvent and dried under vacuum to obtain the covalent organic framework material.

[0058] The mixed solvent comprises m-xylene, 1,4-dioxane, and acetic acid; the volume ratio of m-xylene to acetic acid is 4:1 to 6:1; the volume ratio of 1,4-dioxane to acetic acid is 4:1 to 6:1; and the concentration of acetic acid is 5 mol / L to 7 mol / L.

[0059] The structural formula of the co-reactant is:

[0060] ;

[0061] Where n is an integer from 0 to 9, for example, it can be 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9.

[0062] The structural formula of 1,3,6,8-tetra(4-carboxyphenyl)pyrene is:

[0063] .

[0064] The reaction temperature of 1,3,6,8-tetra(4-formaldehydephenyl)pyrene with the co-reactant is 110℃~130℃, for example, it can be 110℃, 115℃, 120℃, 125℃ or 130℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0065] The reaction time of 1,3,6,8-tetra(4-formaldehydephenyl)pyrene with the co-reactant is 60h to 80h, for example, 60h, 64h, 68h, 72h, 76h or 80h, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0066] The volume ratio of m-xylene to acetic acid is 4:1 to 6:1, for example, it can be 4:1, 5:1 or 6:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0067] The volume ratio of 1,4-dioxane to acetic acid is 4:1 to 6:1, for example, it can be 4:1, 5:1 or 6:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0068] The concentration of acetic acid is 5 mol / L to 7 mol / L, for example, it can be 5 mol / L, 6 mol / L or 7 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0069] Optionally, organic solvent cleaning includes cleaning with tetrahydrofuran followed by acetone in sequence.

[0070] In some embodiments, the thickness of the interface layer is 20nm to 100nm, for example, it can be 20nm, 40nm, 50nm, 60nm, 80nm or 100nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0071] In some embodiments, the thickness of the tin-based perovskite film is 100nm to 400nm, for example, it can be 100nm, 150nm, 200nm, 250nm, 300nm, 350nm or 400nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0072] In some embodiments, the tin-based perovskite material of the tin-based perovskite film has the general formula ABX3, wherein A includes CH3NH3. + CH(NH2)2 + Cs + or Rb + B includes any one or at least two of the following, where B includes Sn. 2+ or Sn 2+ With Pb 2+ The combination of X includes Cl - ,Br - or I - Any one or at least two of them.

[0073] In some embodiments, the conductive substrate layer is made of ITO conductive glass and / or FTO conductive glass.

[0074] In some embodiments, the material of the electron transport layer includes C. 60 The combination of any one or at least two of the following: methyl [6,6]-phenyl-C61-butyrate (PCBM), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), TiO2, SnO2, ZnO, or ZnO-ZnS.

[0075] In some embodiments, the hole transport layer is made of materials including poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), 4-butyl-N,N-diphenylaniline homopolymer (Poly-TPD), polyvinylcarbazole (PVK), and nickel oxide (NiO). x ( ), CuI or CuSCN, or any one or at least a combination of two of them.

[0076] In some embodiments, the electrode layer is made of any one or a combination of at least two of Al, Au, Ag, or carbon.

[0077] Optionally, the thickness of the electron transport layer can be 5nm to 30nm, for example, 5nm, 10nm, 15nm, 20nm, 25nm or 30nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0078] Optionally, the thickness of the hole transport layer can be 30nm~200nm, for example, 30nm, 50nm, 60nm, 80nm, 100nm, 120nm, 150nm, 160nm, 180nm or 200nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0079] Optionally, the thickness of the electrode layer can be 80nm~120nm, for example, 80nm, 90nm, 100nm, 110nm or 120nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0080] Secondly, the present invention provides a method for preparing a tin-based perovskite solar cell, the method comprising the following steps:

[0081] A conductive substrate layer, an electron transport layer, an interface layer, a tin-based perovskite film layer, a hole transport layer, and an electrode layer are sequentially stacked to obtain the tin-based perovskite solar cell described in the first aspect.

[0082] Setting the interface layer includes: coating a covalent organic framework material solution onto the surface of the electron transport layer, followed by annealing to obtain the interface layer.

[0083] In some embodiments, the concentration of the covalent organic framework material in the solution is 1 mg / mL to 5 mg / mL, for example, it can be 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL or 5 mg / mL, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0084] In some embodiments, the solvent in the covalent organic framework material solution includes any one or a combination of at least two of water, ethanol, methanol, or acetonitrile.

[0085] In some embodiments, the annealing temperature is 110°C to 130°C, for example, it can be 110°C, 115°C, 120°C, 125°C or 130°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0086] In some embodiments, the annealing time is 10 min to 20 min, for example, it can be 10 min, 12 min, 15 min, 16 min, 18 min or 20 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0087] In some embodiments, the method for setting the tin-based perovskite film layer includes: preparing a perovskite precursor solution containing tin-based perovskite material, coating it on the surface of the interface layer, and heating it to obtain the tin-based perovskite film layer.

[0088] In some embodiments, the solvent of the perovskite precursor solution includes any one or a combination of at least two of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), 1,3-dimethyl-2-imidazolinone (DMI), dimethylacetamide (DMAC), N,N-dimethylpropenylurea (DMPU), acetonitrile (ACN), or 2-mercaptoethanol (2-ME).

[0089] Thirdly, the present invention provides an optoelectronic device, the optoelectronic device comprising the tin-based perovskite solar cell described in the first aspect, or the tin-based perovskite solar cell prepared by the preparation method described in the second aspect.

[0090] Preparation Example 1

[0091] This preparation example provides a covalent organic framework material, the structural formula of which is:

[0092] ;

[0093] The dashed lines represent sites that connect to another unit, where n is 5.

[0094] In this preparation example, the method for preparing the covalent organic framework material includes:

[0095] 1,3,6,8-Tetra(4-formaldehydephenyl)pyrene (15.5 mg, 0.025 mmol) and co-reactant (0.05 mmol) were placed in a 10 mL heat-resistant glass tube, followed by the addition of a mixed solvent (0.5 mL of m-xylene, 0.5 mL of 1,4-dioxane, and 0.1 mL of 6M acetic acid). The mixture was subjected to three repeated "freeze-vacuum-thaw" treatments, and then the heat-resistant glass tube was sealed and reacted at 120 °C for 72 h. After the reaction was completed, the solid was separated by filtration, washed successively with anhydrous tetrahydrofuran and acetone, and vacuum dried overnight at 80 °C to obtain a covalent organic framework material.

[0096] Preparation Example 2

[0097] This preparation example provides a covalent organic framework material, which is the same as preparation example 1 except that n takes the value of 0.

[0098] Preparation Example 3

[0099] This preparation example provides a covalent organic framework material, which is the same as preparation example 1 except that n takes the value of 9.

[0100] Comparative Preparation Example 1

[0101] This comparative preparation example provides a covalent organic framework material, which is the same as preparation example 1 except that the value of n is 12.

[0102] Example 1

[0103] This embodiment provides a tin-based perovskite solar cell, which includes a conductive substrate layer, an electron transport layer, an interface layer, a tin-based perovskite film layer, a hole transport layer, and an electrode layer stacked together.

[0104] The interface layer contains the covalent organic framework material provided in Preparation Example 1;

[0105] The method for fabricating a tin-based perovskite solar cell provided in this embodiment includes the following steps:

[0106] (1) Cleaning the ITO conductive glass includes ultrasonic cleaning with detergent, deionized water, acetone and anhydrous ethanol in sequence, and then drying with nitrogen gas; wherein the ultrasonic cleaning power is 100Hz and the ultrasonic cleaning time is 15min.

[0107] (2) Spin-coating an electron transport layer on the surface of ITO conductive glass: In an air atmosphere, a pre-prepared SnO2 solution (concentration of 3.67wt%) was spin-coated onto the surface of ITO conductive glass at 4000rpm for 30s, and then placed on a hot plate at 150℃ for annealing for 30min to obtain an electron transport layer with a thickness of 20nm.

[0108] (3) An aqueous solution of the covalent organic framework material containing the covalent organic framework material provided in Preparation Example 1 (concentration of 3 mg / mL) was spin-coated onto the surface of the electron transport layer and annealed at 120°C for 15 min to obtain an interface layer with a thickness of 60 nm.

[0109] The spin coating speed was 2000 rpm and the time was 60 seconds.

[0110] (4) Prepare a tin-based perovskite film on the surface of the interface layer:

[0111] 0.85 M iodine dispersed in DMSO was reacted with excess Sn for 12 h to obtain a SnI2 solution, and 1 mL of this solution was filtered through a 0.45 μm PTFE filter. Subsequently, 0.7225 mmol FAI, 0.1225 mmol PEABr, and 0.085 mmol SnF2 were mixed with the above solution and stirred for 2 h. Finally, the resulting solution was filtered again through a 0.45 μm PTFE filter to obtain a perovskite precursor solution.

[0112] Take 80 μL of the above perovskite precursor solution and spin-coat it onto the surface of the above interface layer at 5000 rpm for 80 s. At 50 s, spin-coat 100 μL of the antisolvent chlorobenzene. At this time, the perovskite film can be observed to turn dark brown. Then, anneal the above substrate at 80 °C for 10 min. The film turns dark black, and a tin-based perovskite film with a thickness of 200 nm is obtained.

[0113] (5) Depositing a hole transport layer on the surface of a tin-based perovskite film: In a glove box, a pre-prepared Spiro-OMeTAD solution (concentration of 72.3 mg / mL) was spin-coated onto the surface of a tin-based perovskite film at a spin speed of 3000 rpm for 30 s to obtain a hole transport layer with a thickness of 100 nm.

[0114] (6) Fabrication of an electrode layer on the surface of the hole transport layer: in a 1×10 -4 Under a vacuum of Pa, gold electrodes were deposited at an evaporation rate of 1 Å / s to obtain an electrode layer with a thickness of 100 nm.

[0115] The ultraviolet spectrum of the tin-based perovskite film prepared in this embodiment is as follows: Figure 1 As shown, the fluorescence spectrum is as follows: Figure 2 As shown.

[0116] Example 2

[0117] This embodiment provides a tin-based perovskite solar cell, which is the same as that in Example 1, except that the covalent organic framework material in the aqueous solution of the covalent organic framework material is provided by Preparation Example 2.

[0118] Example 3

[0119] This embodiment provides a tin-based perovskite solar cell, which is the same as that in Example 1, except that the covalent organic framework material in the aqueous solution of the covalent organic framework material is provided by Preparation Example 3.

[0120] Example 4

[0121] This embodiment provides a tin-based perovskite solar cell, which is the same as in Example 1 except that the concentration of the covalent organic framework material in the aqueous solution is 1 mg / mL.

[0122] Example 5

[0123] This embodiment provides a tin-based perovskite solar cell, which is the same as in Example 1 except that the concentration of the covalent organic framework material in the aqueous solution is 5 mg / mL.

[0124] Example 6

[0125] This embodiment provides a tin-based perovskite solar cell, which is the same as in Example 1 except that the concentration of the covalent organic framework material in the aqueous solution is 0.5 mg / mL.

[0126] Example 7

[0127] This embodiment provides a tin-based perovskite solar cell, which is the same as in Example 1 except that the concentration of the covalent organic framework material in the aqueous solution is 6 mg / mL.

[0128] Example 8

[0129] This embodiment provides a tin-based perovskite solar cell, which includes a conductive substrate layer, an electron transport layer, an interface layer, a tin-based perovskite film layer, a hole transport layer, and an electrode layer stacked together.

[0130] The interface layer contains the covalent organic framework material provided in Preparation Example 1;

[0131] The method for fabricating a tin-based perovskite solar cell provided in this embodiment includes the following steps:

[0132] (1) Cleaning the ITO conductive glass includes ultrasonic cleaning with detergent, deionized water, acetone and anhydrous ethanol in sequence, and then drying with nitrogen gas; wherein the ultrasonic cleaning power is 100Hz and the ultrasonic cleaning time is 15min.

[0133] (2) Spin-coating an electron transport layer on the surface of ITO conductive glass: In an air atmosphere, a pre-prepared SnO2 solution (concentration of 3.67wt%) was spin-coated onto the surface of ITO conductive glass at 4000rpm for 30s, and then placed on a hot plate at 150℃ for annealing for 30min to obtain an electron transport layer with a thickness of 20nm.

[0134] (3) An aqueous solution of the covalent organic framework material containing the covalent organic framework material provided in Preparation Example 1 (concentration of 3 mg / mL) was spin-coated onto the surface of the electron transport layer and annealed at 110 °C for 20 min to obtain an interface layer with a thickness of 20 nm.

[0135] The spin coating speed was 4000 rpm and the time was 60 s;

[0136] (4) Prepare a tin-based perovskite film on the surface of the interface layer:

[0137] 0.85 M iodine dispersed in DMSO was reacted with excess Sn for 12 h to obtain a SnI2 solution, and 1 mL of this solution was filtered through a 0.45 μm PTFE filter. Subsequently, 0.7225 mmol FAI, 0.1225 mmol PEABr, and 0.085 mmol SnF2 were mixed with the above solution and stirred for 2 h. Finally, the resulting solution was filtered again through a 0.45 μm PTFE filter to obtain a perovskite precursor solution.

[0138] Take 80 μL of the above perovskite precursor solution and spin-coat it onto the surface of the above interface layer at 7000 rpm for 80 s. At 50 s, spin-coat 100 μL of the antisolvent chlorobenzene. At this time, the perovskite film can be observed to turn dark brown. Then, anneal the above substrate at 80 °C for 10 min. The film turns dark black, and a tin-based perovskite film with a thickness of 100 nm is obtained.

[0139] (5) Depositing a hole transport layer on the surface of a tin-based perovskite film: In a glove box, a pre-prepared Spiro-OMeTAD solution (concentration of 72.3 mg / mL) was spin-coated onto the surface of a tin-based perovskite film at a spin speed of 3000 rpm for 30 s to obtain a hole transport layer with a thickness of 100 nm.

[0140] (6) Fabrication of an electrode layer on the surface of the hole transport layer: in a 1×10 -4 Under a vacuum of Pa, gold electrodes were deposited at an evaporation rate of 1 Å / s to obtain an electrode layer with a thickness of 100 nm.

[0141] Example 9

[0142] This embodiment provides a tin-based perovskite solar cell, which includes a conductive substrate layer, an electron transport layer, an interface layer, a tin-based perovskite film layer, a hole transport layer, and an electrode layer stacked together.

[0143] The interface layer contains the covalent organic framework material provided in Preparation Example 1;

[0144] The method for fabricating a tin-based perovskite solar cell provided in this embodiment includes the following steps:

[0145] (1) Cleaning the ITO conductive glass includes ultrasonic cleaning with detergent, deionized water, acetone and anhydrous ethanol in sequence, and then drying with nitrogen gas; wherein the ultrasonic cleaning power is 100Hz and the ultrasonic cleaning time is 15min.

[0146] (2) Spin-coating an electron transport layer on the surface of ITO conductive glass: In an air atmosphere, a pre-prepared SnO2 solution (concentration of 3.67wt%) was spin-coated onto the surface of ITO conductive glass at 4000rpm for 30s, and then placed on a hot plate at 150℃ for annealing for 30min to obtain an electron transport layer with a thickness of 20nm.

[0147] (3) An aqueous solution of the covalent organic framework material containing the covalent organic framework material provided in Preparation Example 1 (concentration of 3 mg / mL) was spin-coated onto the surface of the electron transport layer and annealed at 130°C for 10 min to obtain an interface layer with a thickness of 100 nm.

[0148] The spin coating speed was 800 rpm and the time was 60 s;

[0149] (4) Prepare a tin-based perovskite film on the surface of the interface layer:

[0150] 0.85 M iodine dispersed in DMSO was reacted with excess Sn for 12 h to obtain a SnI2 solution, and 1 mL of this solution was filtered through a 0.45 μm PTFE filter. Subsequently, 0.7225 mmol FAI, 0.1225 mmol PEABr, and 0.085 mmol SnF2 were mixed with the above solution and stirred for 2 h. Finally, the resulting solution was filtered again through a 0.45 μm PTFE filter to obtain a perovskite precursor solution.

[0151] Take 80 μL of the above perovskite precursor solution and spin-coat it onto the surface of the above interface layer at 2000 rpm for 80 s. At 50 s, spin-coat 100 μL of the antisolvent chlorobenzene. At this time, the perovskite film can be observed to turn dark brown. Then, anneal the above substrate at 80 °C for 10 min. The film turns dark black, and a tin-based perovskite film with a thickness of 400 nm is obtained.

[0152] (5) Depositing a hole transport layer on the surface of a tin-based perovskite film: In a glove box, a pre-prepared Spiro-OMeTAD solution (concentration of 72.3 mg / mL) was spin-coated onto the surface of a tin-based perovskite film at a spin speed of 3000 rpm for 30 s to obtain a hole transport layer with a thickness of 100 nm.

[0153] (6) Fabrication of an electrode layer on the surface of the hole transport layer: in a 1×10 -4Under a vacuum of Pa, gold electrodes were deposited at an evaporation rate of 1 Å / s to obtain an electrode layer with a thickness of 100 nm.

[0154] Comparative Example 1

[0155] This comparative example provides a tin-based perovskite solar cell, which is the same as Example 1 except that no interface layer is provided. The tin-based perovskite solar cell provided in this comparative example includes a conductive substrate layer, an electron transport layer, a tin-based perovskite film layer, a hole transport layer and an electrode layer stacked together.

[0156] The method for fabricating the tin-based perovskite solar cell provided in this comparative example includes the following steps:

[0157] (1) Cleaning the ITO conductive glass includes ultrasonic cleaning with detergent, deionized water, acetone and anhydrous ethanol in sequence, and then drying with nitrogen gas; wherein the ultrasonic cleaning power is 100Hz and the ultrasonic cleaning time is 15min.

[0158] (2) Spin-coating an electron transport layer on the surface of ITO conductive glass: In an air atmosphere, a pre-prepared SnO2 solution (concentration of 3.67wt%) was spin-coated onto the surface of ITO conductive glass at 4000rpm for 30s, and then placed on a hot plate at 150℃ for annealing for 30min to obtain an electron transport layer with a thickness of 20nm.

[0159] (3) Prepare a tin-based perovskite film on the surface of the electron transport layer:

[0160] 0.85 M iodine dispersed in DMSO was reacted with excess Sn for 12 h to obtain a SnI2 solution, and 1 mL of this solution was filtered through a 0.45 μm PTFE filter. Subsequently, 0.7225 mmol FAI, 0.1225 mmol PEABr, and 0.085 mmol SnF2 were mixed with the above solution and stirred for 2 h. Finally, the resulting solution was filtered again through a 0.45 μm PTFE filter to obtain a perovskite precursor solution.

[0161] Take 80 μL of the above perovskite precursor solution and spin-coat it onto the surface of the electron transport layer at 5000 rpm for 80 s. At 50 s, spin-coat 100 μL of the antisolvent chlorobenzene. At this time, the perovskite film can be observed to turn dark brown. Then, anneal the above substrate at 80 °C for 10 min. The film turns dark black, and a tin-based perovskite film with a thickness of 200 nm is obtained.

[0162] (4) Depositing a hole transport layer on the surface of a tin-based perovskite film: In a glove box, a pre-prepared Spiro-OMeTAD solution (concentration of 72.3 mg / mL) was spin-coated on the surface of a tin-based perovskite film at a spin speed of 3000 rpm for 30 s to obtain a hole transport layer with a thickness of 100 nm.

[0163] (5) Fabrication of an electrode layer on the surface of the hole transport layer: in a 1×10 -4 Under a vacuum of Pa, gold electrodes were deposited at an evaporation rate of 1 Å / s to obtain an electrode layer with a thickness of 100 nm.

[0164] The ultraviolet spectrum of the tin-based perovskite film prepared in this comparative example is shown in the figure below. Figure 1 As shown, the fluorescence spectrum is as follows: Figure 2 As shown.

[0165] Depend on Figure 1 It can be seen that the absorption peak of the tin-based perovskite film in Example 1 exhibits a slight red shift. This is mainly because the carbonyl and amino passivating groups contained in the covalent organic framework material can passivate the lead defects on the surface of the tin-based perovskite film, thereby reducing the pores in the film and increasing the crystal size of the perovskite.

[0166] Depend on Figure 2 It is known that the PL intensity is very high when there is no interface layer beneath the tin-based perovskite film. However, the insertion of the interface layer significantly enhances the PL quenching at the interface between the tin-based perovskite film and the electron transport layer. Quenching is considered to be the charge transfer from the perovskite layer to the electron transport layer, thereby reducing the radiative relaxation from the excited state to the ground state. The introduction of the interface layer effectively promotes electron separation at the interface between the electron transport layer and the tin-based perovskite film.

[0167] Comparative Example 2

[0168] This comparative example provides a tin-based perovskite solar cell, which is identical to Example 1 except that the covalent organic framework material in the aqueous solution of the covalent organic framework material is provided by Comparative Preparation Example 1.

[0169] Performance Characterization

[0170] The testing methods for the tin-based perovskite solar cells provided in the above embodiments and comparative examples include: conducting photoelectric performance tests on the tin-based perovskite solar cells using a standard simulated solar light source (AM1.5G), and the test environment must meet the requirement of a stable irradiance intensity of 1000 W / m². 2 The battery operating temperature must be precisely controlled at 25±2℃, and the battery must be stabilized in a dark environment for 30 minutes before testing to ensure that the spectral matching and irradiation uniformity of the test light source meet the requirements. The test content includes photoelectric conversion efficiency (PCE, %) and short-circuit current density (Jsc, mA / cm²).2 The results are shown in Table 1.

[0171] Table 1

[0172]

[0173] As shown in Table 1, the open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency of the treated tin-based perovskite solar cells are significantly improved. In particular, the photoelectric conversion efficiency is higher when the alkyl chain length of the covalent organic framework material is short (Examples 1, 2, and 3); however, when the alkyl chain length of the covalent organic framework material is too long (Comparative Example 2), it severely affects carrier transport, causing a decrease in efficiency. Furthermore, when the concentration of the aqueous solution of the covalent organic framework material is too low (Example 6), the generation of electron-hole pairs under illumination decreases, thereby reducing the number of electrons migrating from the conduction band to the perovskite surface and inhibiting Sn... 2+ The oxidation effect is not obvious, and the passivation groups contained in the material are also reduced accordingly, which cannot effectively passivate the lead defects on the perovskite surface. These two aspects lead to a decrease in battery efficiency. When the concentration of the aqueous solution of the covalent organic framework material is too high (Example 7), it will lead to an increase in film thickness, which will hinder the conduction of charge carriers and thus lead to a decrease in battery efficiency.

[0174] In summary, the tin-based perovskite solar cell provided by this invention has an interface layer between the electron transport layer and the tin-based perovskite film layer. The covalent organic framework material in the interface layer can generate electron-hole pairs under illumination, wherein electrons in the conduction band migrate to the perovskite surface, which can suppress Sn 2+ The oxidation of the tin-based perovskite film is mitigated by the presence of carbonyl and amino passivating groups in the covalent organic framework material, which are beneficial for passivating metal defects on the surface of the tin-based perovskite film. Therefore, the tin-based perovskite solar cell provided by this invention has high battery performance.

[0175] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A tin-based perovskite solar cell, characterized in that, The tin-based perovskite solar cell includes a conductive substrate layer, an electron transport layer, an interface layer, a tin-based perovskite film layer, a hole transport layer, and an electrode layer stacked together. The interface layer contains a covalent organic framework material, and the structural formula of the covalent organic framework material is as follows: ； In this context, the dashed lines represent sites that connect to another unit, and n is an integer from 0 to 9.

2. The tin-based perovskite solar cell according to claim 1, characterized in that, The method for preparing the covalent organic framework material includes: 1,3,6,8-tetra(4-carboxyphenyl)pyrene and the co-reactant were mixed in a mixed solvent and reacted in a sealed environment at 110℃~130℃ for 60h~80h; the solid product obtained from the reaction was washed with an organic solvent and dried under vacuum to obtain the covalent organic framework material. The mixed solvent comprises m-xylene, 1,4-dioxane, and acetic acid; the volume ratio of m-xylene to acetic acid is 4:1 to 6:1; the volume ratio of 1,4-dioxane to acetic acid is 4:1 to 6:1; and the concentration of acetic acid is 5 mol / L to 7 mol / L. The structural formula of the co-reactant is: ； Where n is an integer from 0 to 9.

3. The tin-based perovskite solar cell according to claim 1, characterized in that, The thickness of the interface layer is 20nm~100nm.

4. The tin-based perovskite solar cell according to claim 1, characterized in that, The thickness of the tin-based perovskite film is 100 nm to 400 nm; And / or, the tin-based perovskite material of the tin-based perovskite film has the general formula ABX3, wherein A includes CH3NH3. + CH(NH2)2 + Cs + or Rb + B includes any one or at least two of the following, where B includes Sn. 2+ or Sn 2+ With Pb 2+ The combination of X includes Cl - ,Br - or I - Any one or at least two of them.

5. The tin-based perovskite solar cell according to any one of claims 1 to 4, characterized in that, The conductive substrate layer is made of ITO conductive glass and / or FTO conductive glass; And / or, the material of the electron transport layer includes C 60 Methyl [6,6]-phenyl-C61-butyrate, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, TiO2, SnO2, ZnO or ZnO-ZnS, or a combination of at least two of these; And / or, the hole transport layer is made of any one or a combination of at least two of the following materials: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, 4-butyl-N,N-diphenylaniline homopolymer, polyvinylcarbazole, nickel oxide, CuI or CuSCN; And / or, the electrode layer is made of any one or a combination of at least two of Al, Au, Ag, or carbon.

6. A method for preparing a tin-based perovskite solar cell, characterized in that, The preparation method includes the following steps: A conductive substrate layer, an electron transport layer, an interface layer, a tin-based perovskite film layer, a hole transport layer, and an electrode layer are sequentially stacked to obtain the tin-based perovskite solar cell according to any one of claims 1 to 5. Setting the interface layer includes: coating a covalent organic framework material solution onto the surface of the electron transport layer, followed by annealing to obtain the interface layer.

7. The preparation method according to claim 6, characterized in that, In the covalent organic framework material solution, the concentration of the covalent organic framework material is 1 mg / mL to 5 mg / mL; And / or, the solvent in the covalent organic framework material solution includes any one or a combination of at least two of water, ethanol, methanol, or acetonitrile.

8. The preparation method according to claim 6, characterized in that, The annealing temperature is 110℃~130℃; And / or, the annealing time is 10 min to 20 min.

9. The preparation method according to any one of claims 6 to 8, characterized in that, The method for setting the tin-based perovskite film layer includes: preparing a perovskite precursor solution containing tin-based perovskite material, coating it on the surface of the interface layer, heating it, and obtaining the tin-based perovskite film layer. And / or, the solvent of the perovskite precursor solution includes any one or a combination of at least two of N,N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolinone, dimethylacetamide, N,N-dimethylpropenylurea, acetonitrile, or 2-mercaptoethanol.

10. An optoelectronic device, characterized in that, The optoelectronic device includes the tin-based perovskite solar cell according to any one of claims 1 to 5, or the tin-based perovskite solar cell prepared by the preparation method according to any one of claims 6 to 9.

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