Perovskite solar cell and preparation method thereof

Abstract

The present application relates to a kind of perovskite solar cell and preparation method thereof, the perovskite solar cell between the hole transport layer and the perovskite film layer, and / or, the electron transport layer and the perovskite film layer are provided with passivation layer, the passivation layer includes organic covalent framework material.The organic covalent framework material used in the present application combines porphyrin unit with pyridine unit, ordered one-dimensional pore structure not only provides efficient adsorption site for noble metal ions, while the structure in pyridine group and formed imine bond can also absorb metal ions, and polybasic heterocyclic structure can also be chelated with metal ions, inhibit migration.In addition, the organic covalent framework material contains abundant passivation group, which can also significantly reduce the defects on the surface of perovskite, improve the performance of perovskite solar cell.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell technology, and specifically to a perovskite solar cell and its fabrication method. Background Technology

[0002] With the continuous development of human society, the demand for energy is increasing. Solar energy is inexhaustible and does not impact the environment, and its application research has received increasing attention. Organic-inorganic hybrid perovskite solar cells (PSCs) have significant advantages such as low cost, high conversion efficiency, and suitability for industrial production. However, their perovskite film layer suffers from the problem of active metal ion migration. When the cell is accidentally damaged (such as by hail or mechanical damage) or improperly disposed of after decommissioning, leakage can easily occur, polluting soil and water bodies and posing a threat to ecosystems and human health. In addition, surface defects are inevitably generated during the fabrication process of the perovskite film layer. These defects can act as non-radiative recombination centers, severely limiting photoelectric conversion efficiency and long-term operational stability.

[0003] Existing technologies offer conventional ion adsorption fixation and defect passivation modification schemes that cannot simultaneously achieve efficient capture and migration inhibition of active metal ions in perovskite films and efficient passivation of intrinsic perovskite defects, thus failing to achieve a synergistic improvement in photoelectric conversion efficiency and stability. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a perovskite solar cell and its preparation method. This perovskite solar cell, through the setting of a passivation layer, can provide efficient adsorption sites for noble metal ions, inhibit the migration of metal ions, and significantly reduce defects on the perovskite surface, thereby improving the performance of the perovskite solar cell.

[0005] To achieve this objective, the present invention employs the following technical solution:

[0006] In a first aspect, the present invention provides a perovskite solar cell, the perovskite solar cell comprising a perovskite film layer, and a hole transport layer and an electron transport layer respectively located on opposite sides of the perovskite film layer;

[0007] A passivation layer is provided between the hole transport layer and the perovskite film layer, and / or between the electron transport layer and the perovskite film layer;

[0008] The passivation layer comprises an organic covalent framework material, the general structural formula of which is:

[0009] ;

[0010] M includes any one of hydrogen, halogen atom, methyl, hydroxyl, aldehyde or cyano group.

[0011] The perovskite solar cell provided by this invention incorporates a passivation layer. Through the use of an organic covalent framework material, the passivation layer combines porphyrin and pyridine units. The ordered one-dimensional porous structure not only provides efficient adsorption sites for noble metal ions, but the pyridine groups and the resulting imine bonds also adsorb metal ions. Furthermore, the multi-component heterocyclic structure chelates with metal ions, inhibiting their migration. In addition, this organic covalent framework material contains abundant passivation groups, which can significantly reduce defects on the perovskite surface and improve the performance of the solar cell.

[0012] In some embodiments, the thickness of the passivation layer is 2 nm to 10 nm.

[0013] In some embodiments, the preparation method of the organic covalent framework material includes: dispersing and dissolving a 4-substituted-2,6-dialdehyde pyridine compound and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin in an organic solvent, adding an acid catalyst; degassing the mixture and sealing it, then carrying out an aldehyde-amine polycondensation reaction under heating conditions; after the reaction is completed, separating the solid product, washing, purifying and drying it to obtain the organic covalent framework material;

[0014] The structural formula of the 4-substituted-2,6-dialdehyde pyridine compound is as follows:

[0015] M includes any one of hydrogen, halogen atom, methyl, hydroxyl, aldehyde or cyano group.

[0016] In some embodiments, the perovskite material in the 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 Pb. 2+ Sn 2+ Or Ge 2+ X includes any one or at least two of the following, where X includes Cl. - ,Br - or I - Any one or at least two of them.

[0017] In a second aspect, the present invention provides a method for fabricating a perovskite solar cell, the method comprising providing a passivation layer between a hole transport layer and the perovskite film layer, and / or, between the electron transport layer and the perovskite film layer, to obtain the perovskite solar cell described in the first aspect;

[0018] The method for preparing the passivation layer includes: coating with a passivation solution and annealing to obtain the passivation layer;

[0019] The passivation solution includes an organic covalent framework material.

[0020] In some embodiments, the concentration of the organic covalent framework material in the passivation solution is 1 mg / mL to 5 mg / mL.

[0021] In some embodiments, the solvent of the passivation solution includes any one or a combination of at least two of isopropanol, chlorobenzene, tetrahydrofuran, or acetone.

[0022] In some embodiments, the annealing temperature is 90°C to 110°C and the time is 8 min to 12 min.

[0023] In some embodiments, the coating method includes spin coating.

[0024] In some embodiments, the spin coating is performed at a speed of 3500 rpm to 4500 rpm for a time of 25 s to 35 s.

[0025] 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.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The perovskite solar cell provided by this invention incorporates a passivation layer. Through the use of an organic covalent framework material, the passivation layer combines porphyrin and pyridine units. The ordered one-dimensional porous structure not only provides efficient adsorption sites for noble metal ions, but the pyridine groups and the resulting imine bonds also adsorb metal ions. Furthermore, the multi-component heterocyclic structure chelates with metal ions, inhibiting their migration. In addition, this organic covalent framework material contains abundant passivation groups, which can significantly reduce defects on the perovskite surface and improve the performance of the solar cell. Attached Figure Description

[0028] Figure 1 These are the JV curves of the solar cells provided in Embodiment 1 and Comparative Example 1 of the present invention;

[0029] Figure 2 These are graphs showing the lead concentration in the aqueous solution after the solar cells were immersed for 8 hours, as provided in Examples 1 to 4 and Comparative Example 1 of this invention. Detailed Implementation

[0030] The descriptions of specific structures or functions implemented according to the inventive concept disclosed in this specification are merely illustrative examples for explaining embodiments of the inventive concept. Those skilled in the art will understand that embodiments of the inventive concept can have various variations and forms, and are not limited to the embodiments described in this specification, but also include various modifications, equivalents, or substitutions made within the scope of the inventive purpose, concept, and technology.

[0031] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the relative orientation or position between different components, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0032] Although the terms "first" or "second" may be used to describe various components or components, the components or components should not be limited by the terms. The terms above are used only to distinguish one component or component from another. For example, without departing from the scope of the invention, a first battery cell may be referred to as a second battery cell, and similarly, a second battery cell may be referred to as a first battery cell.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "connected," "fixed," "set," etc., should be interpreted broadly. For example, when one component is said to "connect" another component, it should be understood that it can be directly or indirectly connected to the other component, meaning that other components may also be present in between. Similarly, the terms "fixed" and "set" should be interpreted broadly in a similar manner. Furthermore, the term "connected" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can refer to the internal connection of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. In this invention, unless otherwise explicitly specified and limited, the description of "above" or "below" the second feature (e.g., the first feature is in direct contact with the second feature) or indirectly through an intermediate medium. Moreover, "above," "on top of," and "over" the second feature can mean the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. The first feature being "below", "under", or "below" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0035] In traditional technologies, various perovskite films generally suffer from the problem of active metal ion migration. In lead-based systems, the soluble lead component is prone to leakage and pollution of soil and water when the device is damaged by mechanical impact or improperly disposed of, posing a potential threat to the ecological environment and human health. Similarly, the active metal ions in low / lead-free perovskite systems also suffer from migration and loss, which not only accelerates the degradation of device performance but also poses corresponding environmental and stability risks. On the other hand, surface and interface defects are inevitably generated during the preparation of various perovskite films. These defects can act as non-radiative recombination centers, severely restricting the photoelectric conversion efficiency and operational stability of the device. Existing conventional packaging strategies can only achieve passive isolation from the external environment, and cannot suppress the migration of metal ions inside the device, nor can they cope with the ion leakage problem after packaging failure. Low / lead-free perovskite alternative systems generally have the disadvantages of lower photoelectric conversion efficiency and environmental stability than mature lead-based systems. Conventional ion adsorption fixation and defect passivation modification schemes cannot simultaneously achieve efficient capture and migration suppression of active metal ions in the perovskite of the whole system and efficient passivation of intrinsic defects of perovskite, and cannot take into account the synergistic improvement of device environmental safety, photoelectric conversion efficiency and long-term stability.

[0036] An embodiment of the present invention provides a perovskite solar cell, the perovskite solar cell comprising a perovskite film layer, and a hole transport layer and an electron transport layer respectively located on opposite sides of the perovskite film layer;

[0037] A passivation layer is provided between the hole transport layer and the perovskite film layer, and / or between the electron transport layer and the perovskite film layer;

[0038] The passivation layer comprises an organic covalent framework material, the general structural formula of which is:

[0039] ;

[0040] M includes any one of hydrogen (-H), halogen atom (any one of -Cl, -Br or -I), methyl (-CH3), hydroxyl (-OH), aldehyde (-CHO) or cyano (-CN).

[0041] The perovskite solar cell provided by this invention incorporates a passivation layer. Through the use of an organic covalent framework material, the passivation layer combines porphyrin and pyridine units. The ordered one-dimensional porous structure not only provides efficient adsorption sites for noble metal ions, but the pyridine groups and the resulting imine bonds also adsorb metal ions. Furthermore, the multi-component heterocyclic structure chelates with metal ions, inhibiting their migration. In addition, this organic covalent framework material contains abundant passivation groups, which can significantly reduce defects on the perovskite surface and improve the performance of the solar cell.

[0042] In some embodiments, the thickness of the passivation layer is 2nm to 10nm, for example, it can be 2nm, 4nm, 5nm, 6nm, 8nm or 10nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0043] In some embodiments, the preparation method of the organic covalent framework material includes: dispersing and dissolving a 4-substituted-2,6-dialdehyde pyridine compound and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin in an organic solvent, adding an acid catalyst; degassing the mixture and sealing it, then carrying out an aldehyde-amine polycondensation reaction under heating conditions; after the reaction is completed, separating the solid product, washing, purifying and drying it to obtain the organic covalent framework material;

[0044] The structural formula of the 4-substituted-2,6-dialdehyde pyridine compound is as follows:

[0045] M includes any one of hydrogen (-H), halogen atom (any one of -Cl, -Br or -I), methyl (-CH3), hydroxyl (-OH), aldehyde (-CHO) or cyano (-CN).

[0046] The structural formula of 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin is as follows:

[0047] .

[0048] In some embodiments, the organic covalent framework material has a structural formula of at least one of the following:

[0049] ;

[0050] ;

[0051] ;

[0052] .

[0053] In some embodiments, the perovskite material in the perovskite film has the general formula ABX3, wherein A includes CH3NH3. + CH(NH2)2 + Cs + or Rb + Any one or at least two combinations of (e.g., CH3NH3) + With CH(NH2)2 + Combination, Cs + With Rb + The combination of CH3NH3 + CH(NH2)2 + With Cs + The combination of, or CH3NH3 + CH(NH2)2 + Cs + With Rb + (combinations, etc.), B includes Pb 2+ Sn 2+ Or Ge 2+ Any one or at least two combinations of Pb 2+ With Sn 2+ The combination of Pb 2+ With Ge 2+ The combination of Sn 2+ With Ge 2+ The combination of, or Pb 2+ Sn 2+ With Ge 2+ (combinations, etc.), X includes Cl- ,Br - or I - Any one or at least two of the above (typical but non-limiting combinations include Cl) - With Br - The combination, Br - with I - The combination, Cl - with I - Combinations, or Cl - ,Br - with I - (combination).

[0054] In some embodiments, the perovskite solar cell includes a transparent conductive layer, a hole transport layer, a perovskite film layer, a passivation layer, an electron transport layer, and an electrode layer stacked together.

[0055] The transparent conductive layer may be made of ITO conductive glass and / or FTO conductive glass.

[0056] In some embodiments, the thickness of the perovskite film can be 300nm to 800nm, for example, 300nm, 400nm, 500nm, 600nm, 700nm or 800nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0057] In some embodiments, the hole transport layer is made of a p-type semiconductor material, which may include any one or a combination of at least two of the following: 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 (Ploy-TPD), polyvinylcarbazole (PVK), [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz) and its derivatives, nickel oxide, CuI, or CuSCN.

[0058] In some embodiments, the electron transport layer is made of an n-type semiconductor material, which may include C 60 Any one or at least two of the following: PCBM, TiO2, SnO2, ZnO, or ZnO-ZnS.

[0059] In some embodiments, the electrode layer may be made of any one or a combination of at least two of Au, Ag, Al, or carbon.

[0060] An embodiment of the present invention provides a method for fabricating a perovskite solar cell, the method comprising providing a passivation layer between a hole transport layer and the perovskite film layer, and / or, between the electron transport layer and the perovskite film layer, to obtain the perovskite solar cell described in any embodiment;

[0061] The method for preparing the passivation layer includes: coating with a passivation solution and annealing to obtain the passivation layer;

[0062] The passivation solution includes an organic covalent framework material.

[0063] In some embodiments, the concentration of the organic covalent framework material in the passivation solution is 1 mg / mL to 5 mg / mL, for example, 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL, or 5 mg / mL, but not limited to the listed values; other unlisted values ​​within the range are also applicable. A suitable concentration of the organic covalent framework material in the passivation solution can obtain a passivation layer of appropriate thickness (2 nm to 10 nm), ensuring the passivation effect, guaranteeing smooth carrier transport, and avoiding a decrease in photoelectric conversion efficiency caused by passivation.

[0064] In some embodiments, the solvent of the passivation solution includes any one or a combination of at least two of isopropanol, chlorobenzene, tetrahydrofuran, or acetone. Typical but non-limiting combinations include a combination of isopropanol and chlorobenzene, a combination of chlorobenzene and tetrahydrofuran, a combination of tetrahydrofuran and acetone, or a combination of isopropanol, chlorobenzene, tetrahydrofuran, and acetone.

[0065] In some embodiments, the annealing temperature is 90°C to 110°C and the time is 8 min to 12 min.

[0066] The annealing temperature is 90℃~110℃, for example, it can be 90℃, 95℃, 100℃, 105℃ or 110℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0067] The annealing time is 8 to 12 minutes, for example, it can be 8 minutes, 9 minutes, 10 minutes, 11 minutes or 12 minutes, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0068] In some embodiments, the coating method includes spin coating.

[0069] In some embodiments, the spin coating is performed at a speed of 3500 rpm to 4500 rpm for a time of 25 s to 35 s.

[0070] The spin coating speed can be 3500rpm~4500rpm, for example, 3500rpm, 3600rpm, 3800rpm, 4000rpm, 4200rpm or 4500rpm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0071] The spin coating time can be 25s to 35s, for example, 25s, 27s, 28s, 30s, 32s, 33s or 35s, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0072] In some embodiments, the method for fabricating the solar cell includes:

[0073] S1. Provide a transparent conductive layer and clean the transparent conductive layer;

[0074] S2. A hole transport layer is formed on the surface of the cleaned transparent conductive layer;

[0075] S3. Preparing a perovskite film on the surface of the hole transport layer, including: coating a perovskite precursor solution onto the surface of the hole transport layer and annealing it to form a perovskite film.

[0076] S4. Using a perovskite film as a substrate, a passivation layer is set on the surface of the perovskite film.

[0077] S5. Deposit an electron transport layer C on the surface of the passivation layer. 60 Then, an electron transport layer (BCP) is deposited, and finally, an electrode layer is prepared.

[0078] In some embodiments, the solvent in the perovskite precursor solution may include 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 (CAN), or 2-mercaptoethanol (ME).

[0079] Preparation Example 1

[0080] This preparation example provides a method for preparing an organic covalent framework material, comprising: dispersing and dissolving 4-bromo-2,6-dialdehyde pyridine (0.06 mmol) and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin (0.03 mmol, 20.3 mg) in 1,4-dioxane (1 mL), and adding acetic acid (6 mol / L, 0.1 mL); placing the mixture in a Pyrex test tube (10 mL), degassing by three freeze-thaw cycles, then sealing the test tube and carrying out an aldehyde-amine polycondensation reaction under heating conditions (120 °C, 3 days); after the reaction, separating the solid product, washing (washing 3 times with tetrahydrofuran and 2 times with acetone), purifying (Soxhlet extraction of tetrahydrofuran for 1 day), and drying (vacuum drying at 80 °C) to obtain the organic covalent framework material.

[0081] .

[0082] Preparation Example 2

[0083] This preparation example provides a method for preparing an organic covalent framework material, comprising: dispersing and dissolving 4-hydroxy-2,6-dialdehyde pyridine (0.06 mmol) and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin (0.03 mmol, 20.3 mg) in 1,4-dioxane (1 mL), and adding acetic acid (6 mol / L, 0.1 mL); placing the mixture in a Pyrex test tube (10 mL), degassing by three freeze-thaw cycles, then sealing the test tube and carrying out an aldehyde-amine polycondensation reaction under heating conditions (120 °C, 3 days); after the reaction, separating the solid product, washing (washing 3 times with tetrahydrofuran and 2 times with acetone), purifying (Soxhlet extraction of tetrahydrofuran for 1 day), and drying (vacuum drying at 80 °C) to obtain the organic covalent framework material.

[0084] .

[0085] Preparation Example 3

[0086] This preparation example provides a method for preparing an organic covalent framework material, comprising: dispersing and dissolving 4-cyano-2,6-dialdehyde pyridine (0.06 mmol) and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin (0.03 mmol, 20.3 mg) in 1,4-dioxane (1 mL), and adding acetic acid (6 mol / L, 0.1 mL); placing the mixture in a Pyrex test tube (10 mL), degassing by three freeze-thaw cycles, then sealing the test tube and carrying out an aldehyde-amine polycondensation reaction under heating conditions (120 °C, 3 days); after the reaction, separating the solid product, washing (washing 3 times with tetrahydrofuran and 2 times with acetone), purifying (Soxhlet extraction of tetrahydrofuran for 1 day), and drying (vacuum drying at 80 °C) to obtain the organic covalent framework material.

[0087] .

[0088] Preparation Example 4

[0089] This preparation example provides a method for preparing an organic covalent framework material, comprising: dispersing and dissolving 2,6-dialdehyde pyridine (0.06 mmol) and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin (0.03 mmol, 20.3 mg) in 1,4-dioxane (1 mL), and adding acetic acid (6 mol / L, 0.1 mL); placing the mixture in a Pyrex test tube (10 mL), degassing by three freeze-thaw cycles, then sealing the test tube and carrying out an aldehyde-amine polycondensation reaction under heating conditions (120 °C, 3 days); after the reaction, separating the solid product, washing (washing 3 times with tetrahydrofuran and 2 times with acetone), purifying (Soxhlet extraction of tetrahydrofuran for 1 day), and drying (vacuum drying at 80 °C) to obtain the organic covalent framework material.

[0090] .

[0091] Example 1

[0092] This embodiment provides a perovskite solar cell, comprising a transparent conductive layer, a hole transport layer, a perovskite film layer, a passivation layer, an electron transport layer, and an electrode layer stacked together, and the fabrication method includes:

[0093] S1. Provide a transparent conductive layer (FTO) and clean the transparent conductive layer; specifically, ultrasonic cleaning is performed with detergent, deionized water, acetone and anhydrous ethanol respectively, and then dried with a nitrogen gun; wherein, the ultrasonic cleaning power is 100Hz and the time is 15min.

[0094] S2. A hole transport layer is formed on the surface of the cleaned transparent conductive layer. Specifically, a hole transport layer solution with a concentration of 0.5 mg / mL prepared from [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (meo-2PACz) is dropped onto the transparent conductive layer, spin-coated at 3000 rpm for 30 s, and then annealed at 100 °C for 10 min to obtain a hole transport layer with a thickness of 2 nm.

[0095] S3. Prepare a perovskite film layer on the surface of the hole transport layer; specifically including:

[0096] 108.33 mg of CsI, 1218.34 mg of FAI, 132.50 mg of MAI, 4033.76 mg of PbI2 and 83.27 mg of MACl were added to a bottle containing a mixed solution (4200 μL of DMF and 840 μL of DMSO) and stirred thoroughly for 12 h to finally form a perovskite precursor solution with a concentration of 1.67 mol / L.

[0097] The perovskite precursor solution was spin-coated onto the hole transport layer at 5000 rpm for 50 s with an acceleration of 1000 rpm. At the 35th second, 200 μL of chlorobenzene was added dropwise. Finally, the mixture was annealed at 120 °C for 15 min to crystallize and form a 450 nm thick perovskite film (material: Cs). 0.05 MA 0.1 FA 0.85 PbI3);

[0098] S4. A passivation solution was spin-coated onto the surface of the perovskite film at a spin speed of 4000 rpm for 30 s, followed by annealing at 100 °C for 10 min to obtain a passivation layer with a thickness of 6 nm.

[0099] The passivation solution is in the form of isopropanol, and the solute is the organic covalent framework material provided in Preparation Example 1, with a concentration of 3 mg / mL.

[0100] S5. Vacuum evaporation is performed on the surface of the passivation layer (vacuum degree is 5×10). -4 An electron transport layer C with a thickness of 20 nm was deposited at a Pa (evaporation rate of 0.15 Å / s). 60 Then vacuum evaporation (vacuum degree 5×10) -4 An electron transport layer (BCP) with a thickness of 8 nm was deposited at a vacuum level of 0.2 Å / s (Pa, evaporation rate of 0.2 Å / s); finally, in a metal evaporation chamber, thermal evaporation (vacuum degree of 5 × 10⁻⁶) was performed. -4 An electrode layer with a thickness of 90 nm was deposited in the electron transport layer BCP (with an evaporation rate of 2 Å / s).

[0101] Example 2

[0102] This embodiment provides a perovskite solar cell, which is the same as that in Example 1 except that the solute in the passivation solution is the organic covalent framework material provided in Preparation Example 2.

[0103] Example 3

[0104] This embodiment provides a perovskite solar cell, which is the same as that in Example 1 except that the solute in the passivation solution is the organic covalent framework material provided in Preparation Example 3.

[0105] Example 4

[0106] This embodiment provides a perovskite solar cell, which is the same as that in Example 1 except that the solute in the passivation solution is the organic covalent framework material provided in Preparation Example 4.

[0107] Example 5

[0108] This embodiment provides a perovskite solar cell, which is the same as in Example 1 except that the solute concentration in the passivation solution is 1 mg / mL and the thickness of the passivation layer is 2 nm.

[0109] Example 6

[0110] This embodiment provides a perovskite solar cell, which is the same as in Example 1 except that the solute concentration in the passivation solution is 5 mg / mL and the thickness of the passivation layer is 10 nm.

[0111] Example 7

[0112] This embodiment provides a perovskite solar cell, which is the same as in Example 1 except that the solute concentration in the passivation solution is 0.2 mg / mL and the thickness of the passivation layer is 0.5 nm.

[0113] Example 8

[0114] This embodiment provides a perovskite solar cell, which is the same as in Example 1 except that the solute concentration in the passivation solution is 10 mg / mL and the thickness of the passivation layer is 20 nm.

[0115] Example 9

[0116] This embodiment provides a perovskite solar cell, comprising a transparent conductive layer, a hole transport layer, a passivation layer, a perovskite film layer, an electron transport layer, and an electrode layer stacked together, and the fabrication method includes:

[0117] S1. Provide a transparent conductive layer (FTO) and clean the transparent conductive layer; specifically, ultrasonic cleaning is performed with detergent, deionized water, acetone and anhydrous ethanol respectively, and then dried with a nitrogen gun; wherein, the ultrasonic cleaning power is 100Hz and the time is 15min.

[0118] S2. A hole transport layer is formed on the surface of the cleaned transparent conductive layer. Specifically, a hole transport layer solution with a concentration of 0.5 mg / mL prepared from [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (meo-2PACz) is dropped onto the transparent conductive layer, spin-coated at 3000 rpm for 30 s, and then annealed at 100 °C for 10 min to obtain a hole transport layer with a thickness of 2 nm.

[0119] S3. Spin-coat the passivation solution onto the surface of the hole transport layer at a spin speed of 4000 rpm for 30 s, and then anneal at 100 °C for 10 min to obtain a passivation layer with a thickness of 6 nm.

[0120] S4. Prepare a perovskite film layer on the surface of the passivation layer, specifically including:

[0121] 108.33 mg of CsI, 1218.34 mg of FAI, 132.50 mg of MAI, 4033.76 mg of PbI2 and 83.27 mg of MACl were added to a bottle containing a mixed solution (4200 μL of DMF and 840 μL of DMSO) and stirred thoroughly for 12 h to finally form a perovskite precursor solution with a concentration of 1.67 mol / L.

[0122] The perovskite precursor solution was spin-coated onto the passivation layer at 5000 rpm for 50 seconds with an acceleration of 1000 rpm. At the 35th second, 200 μL of chlorobenzene was added dropwise. Finally, the mixture was annealed at 120°C for 15 minutes to crystallize and form a 450 nm thick perovskite film (material: Cs). 0.05 MA 0.1 FA 0.85 PbI3);

[0123] S5. Spin-coat the surface of the perovskite film with an isopropanol solution containing piperazine monoiodide material at a concentration of 0.3 mg / mL, at a spin-coating speed of 4000 rpm and a time of 25 s, and then anneal at 100℃ for 10 min to obtain a perovskite passivation layer with a thickness of 2 nm.

[0124] S6. Vacuum evaporation (vacuum degree 5×10) is performed on the surface of the perovskite passivation layer. -4 An electron transport layer C with a thickness of 20 nm was deposited at a Pa (evaporation rate of 0.15 Å / s).60 Then vacuum evaporation (vacuum degree 5×10) -4 An electron transport layer (BCP) with a thickness of 8 nm was deposited at a vacuum level of 0.2 Å / s (Pa, evaporation rate of 0.2 Å / s); finally, in a metal evaporation chamber, thermal evaporation (vacuum degree of 5 × 10⁻⁶) was performed. -4 An electrode layer with a thickness of 90 nm was deposited in the electron transport layer BCP (with an evaporation rate of 2 Å / s).

[0125] Comparative Example 1

[0126] This comparative example provides a perovskite solar cell, which is identical to Example 1 except for the absence of a passivation layer. It includes a stacked transparent conductive layer, a hole transport layer, a perovskite film layer, an electron transport layer, and an electrode layer. The fabrication method includes:

[0127] S1. Provide a transparent conductive layer (FTO) and clean the transparent conductive layer; specifically, ultrasonic cleaning is performed with detergent, deionized water, acetone and anhydrous ethanol respectively, and then dried with a nitrogen gun; wherein, the ultrasonic cleaning power is 100Hz and the time is 15min.

[0128] S2. A hole transport layer is formed on the surface of the cleaned transparent conductive layer. Specifically, a hole transport layer solution with a concentration of 0.5 mg / mL prepared from [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (meo-2PACz) is dropped onto the transparent conductive layer, spin-coated at 3000 rpm for 30 s, and then annealed at 100 °C for 10 min to obtain a hole transport layer with a thickness of 2 nm.

[0129] S3. Prepare a perovskite film layer on the surface of the hole transport layer; specifically including:

[0130] 108.33 mg of CsI, 1218.34 mg of FAI, 132.50 mg of MAI, 4033.76 mg of PbI2 and 83.27 mg of MACl were added to a bottle containing a mixed solution (4200 μL of DMF and 840 μL of DMSO) and stirred thoroughly for 12 h to finally form a perovskite precursor solution with a concentration of 1.67 mol / L.

[0131] The perovskite precursor solution was spin-coated onto the hole transport layer at 5000 rpm for 50 s with an acceleration of 1000 rpm. At the 35th second, 200 μL of chlorobenzene was added dropwise. Finally, the mixture was annealed at 120 °C for 15 min to crystallize and form a 450 nm thick perovskite film (material: Cs). 0.05 MA 0.1 FA 0.85 PbI3);

[0132] S4. Vacuum evaporation is performed on the surface of the perovskite film (vacuum degree is 5×10). -4 An electron transport layer C with a thickness of 20 nm was deposited at a Pa (evaporation rate of 0.15 Å / s). 60 Then vacuum evaporation (vacuum degree 5×10) -4 An electron transport layer (BCP) with a thickness of 8 nm was deposited at a vacuum level of 0.2 Å / s (Pa, evaporation rate of 0.2 Å / s); finally, in a metal evaporation chamber, thermal evaporation (vacuum degree of 5 × 10⁻⁶) was performed. -4 An electrode layer with a thickness of 90 nm was deposited in the electron transport layer BCP (with an evaporation rate of 2 Å / s).

[0133] Performance Characterization

[0134] The performance of the solar cells provided in the above embodiments and comparative examples was characterized, and the results are shown in Table 1. The JV curves of the solar cells provided in Embodiment 1 and Comparative Example 1 are shown in Table 1. Figure 1 As shown, the lead concentration in the aqueous solution of the solar cells provided in Examples 1-4 and Comparative Example 1 after soaking for 8 hours is as follows: Figure 2 As shown, by Figure 2 It is evident that the lead leakage of the solar cell provided in this application embodiment is significantly reduced, effectively demonstrating that the organic covalent framework material in the passivation layer can chelate with lead ions, thereby mitigating lead leakage.

[0135] Table 1

[0136]

[0137] As shown in Table 1, the solar cells provided in this application, through the provision of a passivation layer made of an organic covalent framework material, exhibit significant improvements in open-circuit voltage, short-circuit current density, fill factor, and photoelectric conversion efficiency. When the passivation layer thickness is too thin (Example 7), the reduction in passivation groups in the organic covalent framework material has a significant impact on Pb. 2+ The passivation effect of defects is weakened, resulting in a deterioration in the quality of the thin film and a decrease in the photoelectric conversion efficiency of the solar cell; when the passivation layer is too thick (Example 8), it will hinder carrier transport, thereby affecting the photoelectric conversion efficiency of the solar cell.

[0138] In summary, the perovskite solar cell provided by this invention incorporates a passivation layer. Through the use of an organic covalent framework material, the passivation layer combines porphyrin and pyridine units. The ordered one-dimensional porous structure not only provides efficient adsorption sites for noble metal ions, but the pyridine groups and the resulting imine bonds in this structure can also adsorb metal ions. Furthermore, the multi-component heterocyclic structure can chelate with metal ions, inhibiting migration. In addition, this organic covalent framework material contains abundant passivation groups, which can significantly reduce defects on the perovskite surface and improve the performance of the solar cell.

[0139] 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 perovskite solar cell, characterized in that, The perovskite solar cell includes a perovskite film layer, and a hole transport layer and an electron transport layer located on opposite sides of the perovskite film layer, respectively. A passivation layer is provided between the hole transport layer and the perovskite film layer, and / or between the electron transport layer and the perovskite film layer; The passivation layer comprises an organic covalent framework material, the general structural formula of which is: ； M includes any one of hydrogen, halogen atom, methyl, hydroxyl, aldehyde or cyano group.

2. The perovskite solar cell according to claim 1, characterized in that, The thickness of the passivation layer is 2nm to 10nm.

3. The perovskite solar cell according to claim 1, characterized in that, The preparation method of the organic covalent framework material includes: dispersing and dissolving a 4-substituted-2,6-dialdehyde pyridine compound and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin in an organic solvent, adding an acid catalyst; degassing the mixture and sealing it, then carrying out an aldehyde-amine polycondensation reaction under heating conditions; after the reaction is completed, separating the solid product, washing, purifying and drying it to obtain the organic covalent framework material; The structural formula of the 4-substituted-2,6-dialdehyde pyridine compound is as follows: M includes any one of hydrogen, halogen atom, methyl, hydroxyl, aldehyde or cyano group.

4. The perovskite solar cell according to any one of claims 1 to 3, characterized in that, In the perovskite film, the general formula of the perovskite material is ABX3, where A includes CH3NH3. + CH(NH2)2 + Cs + or Rb + B includes any one or at least two of the following, where B includes Pb. 2+ Sn 2+ Or Ge 2+ X includes any one or at least two of the following, X including Cl - ,Br - Or I - Any one or at least two of them.

5. A method for preparing a perovskite solar cell, characterized in that, The preparation method includes providing a passivation layer between the hole transport layer and the perovskite film layer, and / or between the electron transport layer and the perovskite film layer, to obtain the perovskite solar cell according to any one of claims 1 to 4; The method for preparing the passivation layer includes: coating with a passivation solution and annealing to obtain the passivation layer; The passivation solution includes an organic covalent framework material.

6. The preparation method according to claim 5, characterized in that, The concentration of the organic covalent framework material in the passivation solution is 1 mg / mL to 5 mg / mL.

7. The preparation method according to claim 5 or 6, characterized in that, The solvent of the passivation solution includes any one or a combination of at least two of isopropanol, chlorobenzene, tetrahydrofuran, or acetone.

8. The preparation method according to claim 5, characterized in that, The annealing temperature is 90℃~110℃, and the time is 8min~12min.

9. The preparation method according to claim 5, characterized in that, The coating method includes spin coating.

10. The preparation method according to claim 9, characterized in that, The spin coating speed is 3500rpm~4500rpm, and the time is 25s~35s.

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