Electrode corrosion resistant perovskite solar cell, preparation method and photoelectric device

Abstract

The invention provides an electrode-corrosion-resistant perovskite solar cell, a preparation method and a photoelectric device, and the perovskite solar cell is characterized in that a buffer layer is arranged between a perovskite layer and an electron transmission layer of the perovskite solar cell; and the composition material of the buffer layer comprises an ion covalent organic framework material. The ion covalent organic framework material has very strong adsorption capacity on I2 and can inhibit corrosion of a metal electrode in a perovskite battery, and moreover, the whole ion covalent organic framework material contains high-density imine and triazine and can provide a large number of binding sites for I2; in addition, the affinity between the long-chain alkyl quaternary ammonium salt group and I2 molecules can be further improved by introducing the long-chain alkyl quaternary ammonium salt group; in addition, passivation groups in the ionic covalent organic framework material can passivate Pb < 2 + > defects, so that the quality and the efficiency of the perovskite solar cell are improved.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, and relates to a perovskite solar cell, and more particularly to a perovskite solar cell resistant to electrode corrosion, its preparation method, and optoelectronic devices. Background Technology

[0002] Perovskite solar cells (PSCs) have an efficiency of over 26%. Currently, there is a need to improve the stability of PSCs. The stability problem not only occurs in the perovskite layer, but also in the metal electrode. The corrosion of the metal electrode is the main cause of the degradation of the device.

[0003] For inverted PSCs, perovskite decomposition products such as HI and I2 react with the metal electrode, and this electrode corrosion further accelerates the decomposition of the perovskite, causing a loss of efficiency in the PSCs. Although ion migration is a reversible process, once the migrated ions react with the metal electrode, this reversible process is broken, causing the PSCs to degrade. Therefore, the irreversible degradation of PSCs far exceeds the degradation of the perovskite layer. In inverted PSCs, the electron transport layer is usually located between the metal electrode and the perovskite layer, and the material is usually [6,6]-phenyl-C61-butyrate isomethyl ester (PCBM). Iodine substances in the perovskite layer can diffuse through the electron transport layer and react with the metal electrode, thereby causing electrode corrosion.

[0004] To obtain a stable PSC structure, additional diffusion barriers such as carbon quantum dots, graphene oxide, graphitic carbon nitride, and cross-linked polymers are usually introduced between the perovskite layer and the metal electrode. Although these barriers can alleviate electrode corrosion to some extent, iodine in the perovskite layer can still pass through these diffusion barriers. Therefore, to further improve the stability of perovskite solar cells, it is necessary to overcome the electrode corrosion caused between the metal electrode and the perovskite layer. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a perovskite solar cell, a fabrication method, and an optoelectronic device resistant to electrode corrosion. This perovskite solar cell, through the use of ionic covalent organic framework materials (COFs), reduces the reaction between I2 generated from perovskite decomposition and the metal electrode, thereby improving the quality of the perovskite layer and the cell efficiency of the perovskite solar cell.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a perovskite solar cell resistant to electrode corrosion, wherein a buffer layer is provided between the perovskite layer and the electron transport layer of the perovskite solar cell;

[0008] The buffer layer is composed of ionovalent organic framework materials with the following general chemical formula:

[0009]

[0010] Wherein, R is a quaternary ammonium salt derivative group or a methyl group, and at least one R is a long-chain alkyl quaternary ammonium salt group;

[0011] The number of carbon atoms in the long-chain alkyl quaternary ammonium salt group is n, where n is an integer from 5 to 9, for example, it can be 5, 6, 7, 8 or 9.

[0012] The perovskite solar cell resistant to electrode corrosion provided by this invention utilizes a COFs material with a large surface area, high porosity, and abundant iodine trapping binding sites in the buffer layer. This material exhibits strong adsorption capacity for I2, effectively inhibiting the corrosion of the metal electrodes in the perovskite solar cell. Furthermore, the entire COFs material framework contains a high density of imine and triazine molecules, providing numerous binding sites for I2. Simultaneously, the long-chain alkyl quaternary ammonium salt groups introduced through ion modification further enhance the affinity between the framework and I2 molecules. In addition, this COFs material contains passivating groups such as oxygen-containing and nitrogen-containing functional groups, which can passivate Pb in the perovskite. 2+ To address defects and improve the quality of the perovskite layer and battery efficiency.

[0013] Preferably, the preparation method of the ionic covalent organic framework material includes the following steps:

[0014] The raw materials for preparing ionic covalent organic framework materials are mixed in an organic solvent, reacted, and then post-processed to obtain an intermediate; the intermediate is then modified by ionization to obtain the ionic covalent organic framework material.

[0015] The raw materials for preparation include 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) and 2,5-dimethoxyphenyl-1,4-dicarboxaldehyde (DMTA), or a combination of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, 2,5-dimethoxyphenyl-1,4-dicarboxaldehyde and 2,5-dihydroxyterephthalaldehyde (DHTA);

[0016] Preferably, the structural formula of the ionic compound used for the ionization modification is:

[0017]

[0018] Where X includes any one or a combination of at least two of Cl, Br, or I, and m is an integer from 2 to 6.

[0019] Preferably, the perovskite solar cell comprises a conductive substrate layer, a hole transport layer, a perovskite layer, a buffer layer, an electron transport layer, and a metal electrode layer stacked sequentially.

[0020] Preferably, the thickness of the buffer layer is 20 nm to 100 nm.

[0021] Preferably, the perovskite layer has the general formula ABX3, where A is CH3NH3. + CH(NH2)2 + Cs + or Rb + B is any combination of one or at least two of the following, where B is Pb. 2+ Sn 2+ Or Ge 2+ Any combination of one or at least two of them, X is Cl - ,Br - Or I - Any one or at least two of them.

[0022] Preferably, the thickness of the perovskite layer is 300 nm to 700 nm.

[0023] Preferably, 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.

[0024] Preferably, the material of the metal electrode layer includes any one of Au, Ag, or Al.

[0025] Secondly, the present invention provides a method for preparing a perovskite solar cell resistant to electrode corrosion, the method comprising:

[0026] A buffer layer is placed on the surface of the perovskite layer, and then an electron transport layer is placed on the surface of the buffer layer;

[0027] The buffer layer is composed of ionovalent organic framework materials with the following general chemical formula:

[0028]

[0029] Wherein, R is a quaternary ammonium salt derivative group or a methyl group, and at least one R is a long-chain alkyl quaternary ammonium salt group;

[0030] The number of carbon atoms in the long-chain alkyl quaternary ammonium salt group is n, where n is an integer from 5 to 9.

[0031] Preferably, the preparation method includes the following steps:

[0032] (1) A hole transport layer is prepared on one side surface of the conductive substrate;

[0033] (2) A perovskite precursor solution is coated on the surface of the hole transport layer away from the conductive substrate layer, and heated to generate a perovskite layer.

[0034] (3) A solution containing an ionic covalent organic framework material is spin-coated onto the surface of the perovskite layer away from the hole transport layer, and then annealed to form a buffer layer;

[0035] (4) An electron transport layer is prepared on the surface of the buffer layer away from the perovskite layer;

[0036] (5) Prepare a metal electrode layer on the surface of the electron transport layer away from the buffer layer.

[0037] Preferably, in the solution containing the ionic covalent organic framework material, the solvent includes any one or a combination of at least two of isopropanol, ethanol, butanol, or tetrahydrofuran.

[0038] Preferably, the concentration of the solution containing the ionic covalent organic framework material is from 1 mg / mL to 5 mg / mL.

[0039] Preferably, the spin coating speed is 3500 rpm to 4500 rpm.

[0040] Thirdly, the present invention provides an optoelectronic device, the optoelectronic device comprising the perovskite solar cell described in the first aspect, or the perovskite solar cell prepared by the preparation method described in the second aspect.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] The perovskite solar cell resistant to electrode corrosion provided by this invention utilizes a COFs material with a large surface area, high porosity, and abundant iodine trapping binding sites in the buffer layer. This material exhibits strong adsorption capacity for I2, effectively inhibiting the corrosion of the metal electrodes in the perovskite solar cell. Furthermore, the entire COFs material framework contains a high density of imine and triazine molecules, providing numerous binding sites for I2. Simultaneously, the long-chain alkyl quaternary ammonium salt groups introduced through ion modification further enhance the affinity between the framework and I2 molecules. In addition, this COFs material contains passivating groups such as oxygen-containing and nitrogen-containing functional groups, which can passivate Pb in the perovskite. 2+ To address defects and improve the quality of the perovskite layer and battery efficiency. Attached Figure Description

[0043] Figure 1The XRD patterns of the perovskite layer in the perovskite solar cells obtained in Examples 1, 4 and Comparative Example 1 are shown.

[0044] Figure 2 The fluorescence spectra of the perovskite layer in the perovskite solar cells obtained in Examples 1, 4 and Comparative Example 1 are shown.

[0045] Figure 3 The JV curves are for the perovskite solar cells obtained in Example 1 and Comparative Example 1.

[0046] Figure 4 The graphs show the stability test results of the perovskite solar cells obtained in Examples 1, 4-8 and Comparative Example 1. Detailed Implementation

[0047] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0048] An embodiment of the present invention provides a perovskite solar cell resistant to electrode corrosion, wherein a buffer layer is provided between the perovskite layer and the electron transport layer of the perovskite solar cell;

[0049] The buffer layer is composed of ionovalent organic framework materials with the following general chemical formula:

[0050]

[0051] Wherein, R is a quaternary ammonium salt derivative group or a methyl group, and at least one R is a long-chain alkyl quaternary ammonium salt group;

[0052] The number of carbon atoms in the long-chain alkyl quaternary ammonium salt group is n, where n is an integer from 5 to 9, for example, it can be 5, 6, 7, 8 or 9.

[0053] The perovskite solar cell resistant to electrode corrosion provided by this invention utilizes a COFs material with a large surface area, high porosity, and abundant iodine trapping binding sites in the buffer layer. This material exhibits strong adsorption capacity for I2, effectively inhibiting the corrosion of the metal electrodes in the perovskite solar cell. Furthermore, the entire COFs material framework contains a high density of imine and triazine molecules, providing numerous binding sites for I2. Simultaneously, the long-chain alkyl quaternary ammonium salt groups introduced through ion modification further enhance the affinity between the framework and I2 molecules. In addition, this COFs material contains passivating groups such as oxygen-containing and nitrogen-containing functional groups, which can passivate Pb in the perovskite. 2+ To address defects and improve the quality of the perovskite layer and battery efficiency.

[0054] In some embodiments, the preparation method of the ionic covalent organic framework material includes the following steps:

[0055] The raw materials for preparing ionic covalent organic framework materials are mixed in an organic solvent, reacted, and then post-processed to obtain an intermediate; the intermediate is then modified by ionization to obtain the ionic covalent organic framework material.

[0056] The raw materials for preparation include 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) and 2,5-dimethoxyphenyl-1,4-dicarboxaldehyde (DMTA), or a combination of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, 2,5-dimethoxyphenyl-1,4-dicarboxaldehyde and 2,5-dihydroxyterephthalaldehyde (DHTA).

[0057] In some embodiments, in order to ensure complete reaction between the amino and aldehyde groups, when the raw materials include a combination of TAPT and DMTA, the molar ratio of DMTA to TAPT is 3:2 or higher; when the raw materials include a combination of TAPT, DMTA and DHTA, the ratio of the total molar amount of DMTA and DHTA to the molar amount of TAPT is 3:2 or higher.

[0058] In some embodiments, the ionic compound used for the ionization modification has the following structural formula:

[0059]

[0060] Where X includes any one or a combination of at least two of Cl, Br, or I, and m is an integer from 2 to 6.

[0061] The ionic compounds used in this invention for ionization modification can utilize the hydroxyl groups in the intermediate as reaction sites to achieve ionization modification of the intermediate through Williamson ether reaction.

[0062] As a preferred technical solution for the perovskite solar cell provided by the present invention, the general chemical formula of its intermediate is:

[0063]

[0064] The corresponding chemical formula for ionic covalent organic framework materials is:

[0065]

[0066] Where m is an integer from 2 to 6, for example, it can be 2, 3, 4, 5 or 6.

[0067] In some embodiments, the organic solvent is a mixture of acetic acid, 1,4-dioxane and mesitylene.

[0068] In some embodiments, the perovskite solar cell includes a conductive substrate layer, a hole transport layer, a perovskite layer, a buffer layer, an electron transport layer, and a metal electrode layer stacked sequentially.

[0069] In some embodiments, the conductive substrate layer is made of fluorine-doped tin oxide (FTO) or indium tin oxide (ITO).

[0070] 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] (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), nickel oxide, CuI, CuSCN, (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz), and their derivatives.

[0071] In some embodiments, the thickness of the hole transport layer is 1 nm to 3 nm, for example, it can be 1 nm, 1.5 nm, 2 nm, 2.5 nm or 3 nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0072] In some embodiments, the thickness of the conductive substrate layer is from 80 nm to 200 nm, for example, it can be 80 nm, 100 nm, 120 nm, 150 nm, 180 nm or 200 nm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0073] In some embodiments, the thickness of the buffer layer is from 20 nm to 100 nm, for example, it can be 20 nm, 40 nm, 50 nm, 60 nm, 80 nm or 100 nm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0074] In some embodiments, the perovskite layer is made of the general formula ABX3, where A is CH3NH3. + (MA), CH(NH2)2 + (FA), Cs + or Rb + Any combination of one or at least two of the above, typical but non-limiting combinations include combinations of MA and FA, MA and Cs. + The combination of MA and Rb + The combination of Fa and Cs + With Rb +Combinations, or MA, FA, Cs + With Rb + The combination; B is Pb 2+ Sn 2+ Or Ge 2+ Any one or at least two of the following, typical but non-limiting combinations include Pb 2+ With Sn 2+ The combination of Sn 2+ With Ge 2+ The combination of Pb 2+ With Ge 2+ The combination of, or Pb 2+ Sn 2+ With Ge 2+ Combination of X; X is 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 - The combination of .

[0075] In some embodiments, the thickness of the perovskite layer is 300 nm to 700 nm, for example, it can be 300 nm, 400 nm, 500 nm, 600 nm or 700 nm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0076] In some embodiments, the material of the electron transport layer includes C. 60 Any one or at least two combinations of PCBM, BCP, TiO2, SnO2, ZnO, or ZnO-ZnS, with typical but non-limiting combinations including C. 60 Combinations with PCBM, PCBM and BCP, BCP, TiO2 and SnO2, TiO2, SnO2 and ZnO, or C 60 Combinations of PCBM, BCP, TiO2, SnO2, ZnO and ZnO-ZnS.

[0077] In some embodiments, the thickness of the electron transport layer is from 10 nm to 30 nm, for example, it can be 10 nm, 15 nm, 20 nm, 25 nm or 30 nm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0078] In some embodiments, the material of the metal electrode layer includes any one of Au, Ag, or Al.

[0079] In some embodiments, the thickness of the metal electrode layer is 80-100 nm, for example, it can be 80 nm, 85 nm, 90 nm, 95 nm or 100 nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0080] An embodiment of the present invention provides a method for fabricating a perovskite solar cell resistant to electrode corrosion, the method comprising:

[0081] A buffer layer is placed on the surface of the perovskite layer, and then an electron transport layer is placed on the surface of the buffer layer;

[0082] The buffer layer is composed of ionovalent organic framework materials with the following general chemical formula:

[0083]

[0084] Wherein, R is a quaternary ammonium salt derivative group or a methyl group, and at least one R is a long-chain alkyl quaternary ammonium salt group;

[0085] The number of carbon atoms in the long-chain alkyl quaternary ammonium salt group is n, where n is an integer from 5 to 9, for example, it can be 5, 6, 7, 8 or 9.

[0086] The perovskite solar cell prepared by this invention utilizes a COFs material with a large surface area, high porosity, and abundant iodine trapping binding sites in its buffer layer. This material exhibits strong I2 adsorption capacity, effectively inhibiting corrosion of the metal electrodes in the perovskite solar cell. Furthermore, the entire COFs material framework contains a high density of imine and triazine molecules, providing numerous I2 binding sites. Simultaneously, the long-chain alkyl quaternary ammonium salt groups introduced through ion modification further enhance the affinity between the framework and I2 molecules. In addition, this COFs material contains passivating groups such as oxygen-containing and nitrogen-containing functional groups, which can passivate Pb in the perovskite. 2+ To address defects and improve the quality of the perovskite layer and battery efficiency.

[0087] An embodiment of the present invention provides a method for fabricating a perovskite solar cell resistant to electrode corrosion, the method comprising the following steps:

[0088] (1) A hole transport layer is prepared on one side surface of the conductive substrate;

[0089] (2) A perovskite precursor solution is coated on the surface of the hole transport layer away from the conductive substrate layer, and heated to generate a perovskite layer.

[0090] (3) A solution containing an ionic covalent organic framework material is spin-coated onto the surface of the perovskite layer away from the hole transport layer, and then annealed to form a buffer layer;

[0091] (4) An electron transport layer is prepared on the surface of the buffer layer away from the perovskite layer;

[0092] (5) Prepare a metal electrode layer on the surface of the electron transport layer away from the buffer layer.

[0093] In some embodiments, the solvent in 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 (ME). Typical but non-limiting combinations include combinations of DMF and DMSO, DMSO and NMP, NMP and GBL, GBL and DMI, DMAC, DMPU, ACN, and ME, or combinations of DMF, DMSO, NMP, GBL, DMI, DMAC, DMPU, ACN, and ME.

[0094] In some embodiments, the solvent in the solution containing the ionic covalent organic framework material includes any one or a combination of at least two of isopropanol, ethanol, butanol, or tetrahydrofuran. Typical but non-limiting combinations include combinations of isopropanol and ethanol, ethanol and butanol, butanol and tetrahydrofuran, or combinations of isopropanol, ethanol, butanol, and tetrahydrofuran.

[0095] In some embodiments, the concentration of the solution containing the ionic covalent organic framework material is from 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.

[0096] In this invention, the concentration of the solution containing the ionic covalent organic framework material is related to the thickness of the final buffer layer; the higher the concentration, the thicker the layer. This invention controls the concentration to be between 1 mg / mL and 5 mg / mL, which allows the thickness of the buffer layer to be controlled within the range of 20 nm to 100 nm.

[0097] In some embodiments, the spin coating speed is 3500 rpm to 4500 rpm, for example, 3500 rpm, 3800 rpm, 4000 rpm, 4200 rpm or 4500 rpm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0098] An embodiment of the present invention provides an optoelectronic device, the optoelectronic device comprising a perovskite solar cell as described in any embodiment, or a perovskite solar cell prepared by any of the preparation methods described in any embodiment.

[0099] Preparation Example 1

[0100] This preparation example provides an ion-covalent organic framework material, the preparation method of which includes the following steps:

[0101] (1) Dissolve TAPT (2 mmol, 70.8 mg), DMTA (1.5 mmol, 29.1 mg) and DHTA (1.5 mmol, 24.9 mg) in a mixed solvent (0.2 mL of 6 M acetic acid + 0.3 mL of 1,4-dioxane + 1.7 mL of trimethylbenzene) and sonicate for 15 min to disperse them evenly.

[0102] (2) The mixture was rapidly frozen at 77K, degassed three times by a freeze pump-thaw cycle, and then sealed and heated at 120℃ for 3 days. After the reaction was completed, it was filtered, then Soxhlet extracted in tetrahydrofuran (THF) for 48h, and vacuum dried overnight at 100℃ to obtain the intermediate.

[0103] (3) Using the hydroxyl group as the reaction site, the intermediate was modified with an ionic compound (2-bromoethyltrimethylammonium bromide) via the Williamson ether reaction: 200 mg of the intermediate, 100 mg of the ionic compound, and 50 mg of K2CO3 were mixed, and 20 mL of degassed anhydrous DMF was introduced under a nitrogen atmosphere. The mixture was stirred at room temperature for 24 h, then heated at 140 °C for 3 days. The resulting product was filtered and separated, then washed with DMF and THF, and vacuum dried overnight at 100 °C to obtain the ionic covalent organic framework material, whose chemical structural formula is:

[0104]

[0105] Where m is 2.

[0106] Preparation Example 2

[0107] This preparation example provides an ionic covalent organic framework material. Except that the ionic compound used to prepare the ionic covalent organic framework material is 4-bromobutyltrimethylammonium bromide, and the m in the chemical structural formula of the obtained ionic covalent organic framework material is 4, everything else is the same as in Preparation Example 1.

[0108] Preparation Example 3

[0109] This preparation example provides an ionic covalent organic framework material. Except that the ionic compound used to prepare the ionic covalent organic framework material is 6-bromohexyltrimethylammonium bromide, and the m in the chemical structural formula of the obtained ionic covalent organic framework material is 6, everything else is the same as in Preparation Example 1.

[0110] Preparation Example 4

[0111] This preparation example provides an ionic covalent organic framework material, which differs from Preparation Example 1 in that the TAPT in this preparation example is 2 mmol, the DMTA is 2.5 mmol, and the DHTA is 0.5 mmol.

[0112] In the ionic covalent organic framework material obtained in this preparation example, m is 2.

[0113] Preparation Example 5

[0114] This preparation example provides an ionic covalent organic framework material, which differs from Preparation Example 1 in that the TAPT in this preparation example is 2 mmol, the DMTA is 0 mmol, and the DHTA is 3 mmol.

[0115] In the ionic covalent organic framework material obtained in this preparation example, m is 2.

[0116] Comparative Preparation Example 1

[0117] This comparative preparation example provides an ionic covalent organic framework material. The difference between this preparation example and preparation example 1 is that the TAPT content in this preparation example is 2 mmol, the DMTA content is 3 mmol, and the DHTA content is 0 mmol.

[0118] Example 1

[0119] This embodiment provides a perovskite solar cell, comprising a conductive substrate layer, a hole transport layer, a perovskite layer, a buffer layer, an electron transport layer, and a metal electrode layer stacked sequentially, and its fabrication method includes the following steps:

[0120] (1) The conductive substrate (FTO) was ultrasonically cleaned at a power of 100 Hz for 15 min and then dried with nitrogen. Then, a hole transport layer was spin-coated on one side of the conductive substrate: 0.5 mg / mL of [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid was added to the conductive substrate and spin-coated at 3000 rpm for 30 s. Then, it was annealed at 100 °C for 10 min to obtain a hole transport layer with a thickness of 2 nm.

[0121] (2) A perovskite precursor solution is coated on the surface of the hole transport layer away from the conductive substrate layer, and heated to generate a perovskite layer:

[0122] MAI, FAI, MACl, and PbI2 were dissolved in a mixed solvent (DMSO and DMF, volume ratio 1:9) and heated and stirred at 70°C for 1 hour to completely dissolve the solvent, yielding a perovskite precursor solution (FAI concentration 1.5 mol / L, PbI2 concentration 1.5 mol / L, FAI, MAI, and MACl concentration ratio 0.95:0.05:0.14). The perovskite precursor solution was then spin-coated onto a hole transport layer at 5000 rpm for 50 s, followed by annealing at 120°C for 15 min to obtain a perovskite layer with a thickness of 450 nm (FAI, MAI, and MACl). 0.95 MA 0.05 PbI3);

[0123] (3) On the surface of the perovskite layer away from the hole transport layer, spin-coat an isopropanol solution containing ionic covalent organic framework material at a concentration of 3 mg / mL for 30 s at a speed of 4000 rpm, and anneal at 80°C for 6 min to form a buffer layer with a thickness of 60 nm.

[0124] The ionic covalent organic framework material was provided by Preparation Example 1;

[0125] (4) On the surface of the buffer layer away from the perovskite layer, under a vacuum of 5×10 -4 Under conditions of Pa and an evaporation rate of 0.15 A / s, a C layer with a thickness of 20 nm was deposited by vacuum evaporation. 60 Layer; then in a vacuum of 5×10 -4 A BCP layer with a thickness of 8 nm was deposited by vacuum evaporation under the conditions of Pa and evaporation rate of 0.2 A / s.

[0126] (5) Under a vacuum degree of 5×10 -4 Under the conditions of Pa and an evaporation rate of 0.2 A / s, an Ag electrode layer with a thickness of 90 nm was prepared by physical vapor deposition on the surface of the BCP layer away from the buffer layer.

[0127] The XRD pattern of the perovskite layer in the perovskite solar cell provided in this embodiment is as follows: Figure 1 As shown, the fluorescence spectrum is as follows: Figure 2 As shown; the JV curve of the perovskite solar cell is as follows. Figure 3 As shown in the figure, the stability test graph is as follows. Figure 4 As shown.

[0128] Example 2

[0129] This embodiment provides a perovskite solar cell, which is the same as that in Example 1 except that the ionic covalent organic framework material in step (3) is provided by Preparation Example 2.

[0130] Example 3

[0131] This embodiment provides a perovskite solar cell, which is the same as that in Example 1 except that the ionic covalent organic framework material in step (3) is provided by Preparation Example 3.

[0132] Example 4

[0133] This embodiment provides a perovskite solar cell, which is the same as that in Example 1 except that the ionic covalent organic framework material in step (3) is provided by Preparation Example 4.

[0134] The XRD pattern of the perovskite layer in the perovskite solar cell provided in this embodiment is as follows: Figure 1 As shown, the fluorescence spectrum is as follows: Figure 2 As shown; the stability test results of the perovskite solar cell are as follows. Figure 4 As shown.

[0135] Example 5

[0136] This embodiment provides a perovskite solar cell, which is the same as that in Example 1 except that the ionic covalent organic framework material in step (3) is provided by Preparation Example 2.

[0137] The stability test results of the perovskite solar cell obtained in this embodiment are shown in the figure below. Figure 4 As shown.

[0138] Example 6

[0139] This embodiment provides a perovskite solar cell, comprising a conductive substrate layer, a hole transport layer, a perovskite layer, a buffer layer, an electron transport layer, and a metal electrode layer stacked sequentially. Except for step (3), the preparation method is the same as that in Example 1.

[0140] Step (3) in this embodiment includes: spin-coating an isopropanol solution containing an ionic covalent organic framework material at a concentration of 1 mg / mL for 30 s at a speed of 4500 rpm on the surface of the perovskite layer away from the hole transport layer, and annealing at 80°C for 6 min to form a buffer layer with a thickness of 20 nm; the ionic covalent organic framework material is provided by Preparation Example 1.

[0141] The stability test results of the perovskite solar cell obtained in this embodiment are shown in the figure below. Figure 4 As shown.

[0142] Example 7

[0143] This embodiment provides a perovskite solar cell, comprising a conductive substrate layer, a hole transport layer, a perovskite layer, a buffer layer, an electron transport layer, and a metal electrode layer stacked sequentially. Except for step (3), the preparation method is the same as that in Example 1.

[0144] Step (3) in this embodiment includes: spin-coating an isopropanol solution containing an ionic covalent organic framework material at a concentration of 5 mg / mL for 30 s at a speed of 3500 rpm on the surface of the perovskite layer away from the hole transport layer, and annealing at 80°C for 6 min to form a buffer layer with a thickness of 100 nm; the ionic covalent organic framework material is provided by Preparation Example 1.

[0145] The stability test results of the perovskite solar cell obtained in this embodiment are shown in the figure below. Figure 4 As shown.

[0146] Example 8

[0147] This embodiment provides a perovskite solar cell, comprising a conductive substrate layer, a hole transport layer, a perovskite layer, a buffer layer, an electron transport layer, and a metal electrode layer stacked sequentially. Except for step (3), the preparation method is the same as that in Example 1.

[0148] Step (3) in this embodiment includes: spin-coating an isopropanol solution containing an ionic covalent organic framework material at a concentration of 0.5 mg / mL for 30 s at a speed of 5000 rpm on the surface of the perovskite layer away from the hole transport layer, and annealing at 80°C for 6 min to form a buffer layer with a thickness of 10 nm; the ionic covalent organic framework material is provided by Preparation Example 1.

[0149] The stability test results of the perovskite solar cell obtained in this embodiment are shown in the figure below. Figure 4 As shown.

[0150] Example 9

[0151] This embodiment provides a perovskite solar cell, comprising a conductive substrate layer, a hole transport layer, a perovskite layer, a buffer layer, an electron transport layer, and a metal electrode layer stacked sequentially. Except for step (3), the preparation method is the same as that in Example 1.

[0152] Step (3) in this embodiment includes: spin-coating an isopropanol solution containing an ionic covalent organic framework material at a concentration of 7 mg / mL for 30 s at a speed of 3000 rpm on the surface of the perovskite layer away from the hole transport layer, and annealing at 80°C for 6 min to form a buffer layer with a thickness of 120 nm; the ionic covalent organic framework material is provided by Preparation Example 1.

[0153] Comparative Example 1

[0154] This comparative example provides a perovskite solar cell, comprising a conductive substrate layer, a hole transport layer, a perovskite layer, an electron transport layer, and a metal electrode layer sequentially stacked, and its fabrication method includes the following steps:

[0155] (1) The conductive substrate (FTO) was ultrasonically cleaned at a power of 100 Hz for 15 min and then dried with nitrogen. Then, a hole transport layer was spin-coated on one side of the conductive substrate: 0.5 mg / mL of [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid was added to the conductive substrate and spin-coated at 3000 rpm for 30 s. Then, it was annealed at 100 °C for 10 min to obtain a hole transport layer with a thickness of 2 nm.

[0156] (2) A perovskite precursor solution is coated on the surface of the hole transport layer away from the conductive substrate layer, and heated to generate a perovskite layer:

[0157] MAI, FAI, MACl, and PbI2 were dissolved in a mixed solvent (DMSO and DMF, volume ratio 1:9) and heated and stirred at 70°C for 1 hour to completely dissolve the solvent, yielding a perovskite precursor solution (FAI concentration 1.5 mol / L, PbI2 concentration 1.5 mol / L, FAI, MAI, and MACl concentration ratio 0.95:0.05:0.14). The perovskite precursor solution was then spin-coated onto a hole transport layer at 5000 rpm for 50 s, followed by annealing at 120°C for 15 min to obtain a perovskite layer with a thickness of 450 nm (FAI, MAI, and MACl). 0.95 MA 0.05 PbI3);

[0158] (3) On the surface of the buffer layer away from the perovskite layer, under a vacuum of 5×10⁻⁶ -4Under conditions of Pa and an evaporation rate of 0.15 A / s, a C layer with a thickness of 20 nm was deposited by vacuum evaporation. 60 Layer; then in a vacuum of 5×10 -4 A BCP layer with a thickness of 8 nm was deposited by vacuum evaporation under the conditions of Pa and evaporation rate of 0.2 A / s.

[0159] (4) At a vacuum degree of 5×10 -4 Under the conditions of Pa and an evaporation rate of 0.2 A / s, an Ag electrode layer with a thickness of 90 nm was prepared by physical vapor deposition on the surface of the BCP layer away from the buffer layer.

[0160] In other words, compared to Example 1, the perovskite solar cell provided in Comparative Example 1 does not have a buffer layer, and its XRD pattern of the perovskite layer is as follows. Figure 1 As shown, the fluorescence spectrum is as follows: Figure 2 As shown; the JV curve of the perovskite solar cell is as follows. Figure 3 As shown in the figure, the stability test graph is as follows. Figure 4 As shown.

[0161] Comparative Example 2

[0162] This comparative example provides a perovskite solar cell, which is identical to Example 1 except that the ionic covalent organic framework material in step (3) is provided by Comparative Preparation Example 1.

[0163] Performance Characterization

[0164] In this invention, Figure 1 The XRD patterns of the perovskite layer in the perovskite solar cells obtained in Examples 1, 4, and Comparative Example 1 are shown below (using XRD patterns of the perovskite layer). (Using X-rays as the source, the scanning range is 2θ = 5°-40°, and the scanning speed is 5° / min); Figure 1 It can be seen that the XRD diffraction peak positions of the perovskite layer treated with COFs material are consistent with those of the perovskite layer without COFs material treatment, and there are no other impurity peaks; Figure 1 It can be seen that the relative height of PbI2 diffraction peak 1 in the perovskite layer after COFs treatment is significantly reduced. Therefore, the buffer layer can passivate Pb defects and reduce nonradiative recombination.

[0165] Figure 2 The fluorescence spectra of the perovskite layer in the perovskite solar cells obtained in Examples 1, 4 and Comparative Example 1 (using a xenon lamp (Xe 900) with a wavelength of 500 nm) are shown. The emission peak of the fluorescence spectrum of the perovskite layer after treatment with COFs material is significantly improved, indicating that the defects of the perovskite film are reduced after treatment, and the film quality of the perovskite layer is improved.

[0166] Figure 3 J-V curve diagram of the perovskite solar cells obtained in Example 1 and Comparative Example 1;

[0167] Figure 4 Stability test diagram of the perovskite solar cells obtained in Example 1, Examples 4-8 and Comparative Example 1; It can be seen from Figure 4 that after 1000 h, the stability of the perovskite solar cells treated with COFs materials can still maintain more than 70% of the initial value. This is mainly because the synergistic effect of the high-density imine and triazine molecules and ionic sites contained in the COFs materials promotes the adsorption of I2, inhibits metal corrosion, and improves the stability of the perovskite solar cells.

[0168] The open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and photoelectric conversion efficiency (PCE) of the perovskite solar cells obtained in the above examples and comparative examples were tested. The test results are shown in Table 1. The test conditions were: using a solar simulation test device for testing, the light source was a 500 W xenon lamp solar spectrum simulator, and the test was carried out under the condition of one solar light intensity (AM 1.5G: 100 mW / cm 2 2).

[0169] Table 1

[0170] Voc(V) <![CDATA[Jsc(mA / cm 2 )]]> FF (%) PCE (%) Example 1 1.21 25.1 78.0 23.7 Example 2 1.21 25.0 78.3 23.7 Example 3 1.20 25.2 77.9 23.5 Example 4 1.19 25.5 77.7 23.6 Example 5 1.21 24.8 77.9 23.4 Example 6 1.20 25.1 78.0 23.5 Example 7 1.20 24.9 78.2 23.4 Example 8 1.18 24.6 76.4 22.2 Example 9 1.17 24.8 76.7 22.3 Comparative Example 1 1.14 23.7 75.9 20.5 Comparative Example 2 1.15 24.2 76.8 21.4

[0171] It can be seen from Table 1 that by setting the buffer layer containing COFs materials, the open-circuit voltage, short-circuit current density, fill factor, and photoelectric conversion efficiency of the perovskite solar cells are significantly improved; from the comparison of Example 8, Example 9 and Example 1, it can be seen that if the thickness of the buffer layer is too high, the adsorption effect of I2 will be reduced, resulting in a decrease in the stability of the perovskite solar cells. The passivation effect of passivation groups such as oxygen-containing functional groups and nitrogen-containing functional groups on Pb 2+ defects will also be weakened, resulting in a deterioration of the quality of the perovskite layer and a decrease in the efficiency of the perovskite solar cells; while when the thickness of the buffer layer is too thick, it will hinder the transport of carriers and affect the efficiency of the perovskite solar cells.

[0172] In summary, the perovskite solar cell resistant to electrode corrosion provided by this invention utilizes a COFs material with a large surface area, high porosity, and abundant iodine trapping binding sites in the buffer layer. This material exhibits a strong adsorption capacity for I2, effectively inhibiting the corrosion of the metal electrodes in the perovskite solar cell. Furthermore, the entire COFs material framework contains a high density of imine and triazine molecules, providing numerous binding sites for I2. Simultaneously, the long-chain alkyl quaternary ammonium salt groups introduced through ion modification further enhance the affinity between the framework and I2 molecules. In addition, this COFs material contains passivating groups such as oxygen-containing and nitrogen-containing functional groups, which can passivate Pb in the perovskite. 2+ To address defects and improve the quality of the perovskite layer and battery efficiency.

[0173] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A perovskite solar cell resistant to electrode corrosion, characterized in that, A buffer layer is provided between the perovskite layer and the electron transport layer of the perovskite solar cell; The buffer layer is composed of ionovalent organic framework materials with the following general chemical formula: Wherein, R is a quaternary ammonium salt derivative group or a methyl group, and at least one R is a long-chain alkyl quaternary ammonium salt group; The number of carbon atoms in the long-chain alkyl quaternary ammonium salt group is n, where n is an integer from 5 to 9.

2. The perovskite solar cell according to claim 1, characterized in that, The preparation method of the ion-covalent organic framework material includes the following steps: The raw materials for preparing ionic covalent organic framework materials are mixed in an organic solvent, reacted, and then post-processed to obtain an intermediate; the intermediate is then modified by ionization to obtain the ionic covalent organic framework material. The raw materials for preparation include 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and 2,5-dimethoxyphenyl-1,4-dicarboxaldehyde, or a combination of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, 2,5-dimethoxyphenyl-1,4-dicarboxaldehyde and 2,5-dihydroxyterephthalaldehyde; Preferably, the structural formula of the ionic compound used for the ionization modification is: Where X includes any one or a combination of at least two of Cl, Br, or I, and m is an integer from 2 to 6.

3. The perovskite solar cell according to claim 1 or 2, characterized in that, The perovskite solar cell comprises a conductive substrate layer, a hole transport layer, a perovskite layer, a buffer layer, an electron transport layer, and a metal electrode layer stacked sequentially. And / or, the thickness of the buffer layer is 20 nm to 100 nm.

4. The perovskite solar cell according to claim 3, characterized in that, The general formula for the perovskite layer is ABX3, where A is CH3NH3. + CH(NH2)2 + Cs + or Rb + B is any combination of one or at least two of the following, where B is Pb. 2+ Sn 2+ Or Ge 2+ Any combination of one or at least two of them, X is Cl - ,Br - Or I - Any one or at least two of them; And / or, the thickness of the perovskite layer is 300 nm to 700 nm.

5. The perovskite solar cell according to claim 3, characterized in that, 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.

6. The perovskite solar cell according to claim 3, characterized in that, The material of the metal electrode layer includes any one of Au, Ag, or Al.

7. A method for fabricating a perovskite solar cell resistant to electrode corrosion, characterized in that, The preparation method includes: A buffer layer is placed on the surface of the perovskite layer, and then an electron transport layer is placed on the surface of the buffer layer; The buffer layer is composed of ionovalent organic framework materials with the following general chemical formula: Wherein, R is a quaternary ammonium salt derivative group or a methyl group, and at least one R is a long-chain alkyl quaternary ammonium salt group; The number of carbon atoms in the long-chain alkyl quaternary ammonium salt group is n, where n is an integer from 5 to 9.

8. The preparation method according to claim 7, characterized in that, The preparation method includes the following steps: (1) A hole transport layer is prepared on one side surface of the conductive substrate; (2) A perovskite precursor solution is coated on the surface of the hole transport layer away from the conductive substrate layer, and heated to generate a perovskite layer. (3) A solution containing an ionic covalent organic framework material is spin-coated onto the surface of the perovskite layer away from the hole transport layer, and then annealed to form a buffer layer; (4) An electron transport layer is prepared on the surface of the buffer layer away from the perovskite layer; (5) Prepare a metal electrode layer on the surface of the electron transport layer away from the buffer layer.

9. The preparation method according to claim 8, characterized in that, In the solution containing the ionic covalent organic framework material, the solvent includes any one or a combination of at least two of isopropanol, ethanol, butanol or tetrahydrofuran; And / or, the concentration of the solution containing the ionic covalent organic framework material is from 1 mg / mL to 5 mg / mL; And / or, the spin coating speed is 3500 rpm to 4500 rpm.

10. An optoelectronic device, characterized in that, The optoelectronic device includes the perovskite solar cell according to any one of claims 1 to 6, or the perovskite solar cell prepared by the preparation method according to any one of claims 7 to 9.

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