A method for preparing a perovskite solar cell and a perovskite solar cell

Abstract

The present invention provides a method for preparing a perovskite solar cell and a perovskite solar cell. The method comprises adding an amino acid derivative additive to a perovskite precursor solution to improve the film quality of the perovskite absorber layer and passivate intracrystalline defects and grain boundaries, thereby improving the conversion efficiency and stability of the perovskite thin-film cell. The present invention also provides a perovskite solar cell prepared by the above method.

Description

Technical Field

[0001] The present invention belongs to the field of perovskite solar cells, and in particular relates to a preparation method of a perovskite solar cell and a perovskite solar cell. Background Art

[0002] Perovskite solar cells (PSCs), a new and highly anticipated solar cell technology, offer significant potential in the renewable energy sector due to their high photoelectric conversion efficiency, low cost, and ease of fabrication. However, the commercial application of PSCs is severely hampered by device stability, a problem primarily due to inherent defects in the perovskite material.

[0003] Defects in perovskite crystals can lead to charge localization, non-radiative recombination, and crystal degradation, seriously affecting the long-term stability and performance of devices. In particular, there are a large number of defects on the surface of perovskite crystals or at grain boundaries (GBs). These defects can trigger adverse reactions such as carrier recombination and charge recombination, seriously affecting the performance and stability of PSCs.

[0004] To address this issue, researchers have proposed methods to optimize device performance by adjusting the perovskite composition. However, simply optimizing the perovskite composition is far from sufficient to meet the high demands of commercial PSCs. Instead, further research is needed to improve the morphology and crystal quality of perovskite films to achieve high-performance and high-stability PSCs. Summary of the Invention

[0005] The present invention aims to address at least one of the aforementioned technical problems existing in the prior art. To this end, the present invention provides a method for preparing a perovskite solar cell. By using an additive containing an amino acid derivative, the nucleation and crystal growth rates are regulated, resulting in a uniform and dense perovskite film. This improves the film quality of the perovskite absorber layer and effectively passivates defects within the crystal and at grain boundaries, reducing non-radiative recombination of carriers and improving cell efficiency and photothermal stability.

[0006] The present invention also provides a perovskite solar cell.

[0007] A first aspect of the present invention provides a method for preparing a perovskite solar cell, the method comprising adding an amino acid derivative additive to a perovskite precursor solution to improve the film quality of the perovskite absorber layer and passivate intracrystalline defects and grain boundaries, thereby improving the conversion efficiency and stability of the perovskite thin-film battery, wherein the amino acid derivative additive comprises at least one of FMOC-D-valine, Fmoc-N-Me-L-valine, N-benzyloxycarbonyl-D-valine, benzoyl-DL-valine and L-valine.

[0008] A technical solution in the method for preparing a perovskite solar cell according to the present invention has at least the following beneficial effects:

[0009] The structural design and function of additives or ligands can effectively passivate various defects. By studying the relationship between the control of perovskite film defects and stability by additives or ligands, it is helpful to solve the problem of stability of perovskite solar cells. In order to solve the problems of low efficiency and poor stability in existing perovskite thin film battery technology, the present invention uses additives containing amino acid derivatives to regulate the nucleation and crystal growth rates to produce a uniform and dense perovskite film, improve the film quality of the perovskite absorber layer, and effectively passivate defects within the crystal and grain boundaries, reduce non-radiative recombination of carriers, and improve battery efficiency and photothermal stability. Amino acid derivative additives are mainly used to improve the perovskite absorber layer in the perovskite thin film battery structure. This method is applicable to two commonly used perovskite thin film battery structures: NIP and PIN.

[0010] The introduction of amino acid derivatives into perovskite precursors is mainly to passivate defects in the functional groups of various derivatives, improve efficiency and stability, and form high-quality perovskite films. Specific beneficial effects also include:

[0011] The open circuit voltage increases by about 50-100mV;

[0012] Improved stability: After 500 hours of photothermal stability testing at 70°C in a nitrogen atmosphere under one sun, the stability results of the device showed that the device exhibited excellent long-term stability. The test results of the amino acid derivative structures with different designs showed that the retention rate of the original efficiency was greatly improved.

[0013] According to some embodiments of the present invention, the components of the perovskite precursor solution include the amino acid derivative additive, a precursor, and a solvent.

[0014] According to some embodiments of the present invention, the precursor includes at least one of cesium iodide, lead iodide, methylammonium chloride, formamidine iodide, lead bromide and methylammonium bromide.

[0015] According to some embodiments of the present invention, the solvent includes at least one of dimethyl sulfoxide and N,N-dimethylformamide.

[0016] According to some embodiments of the present invention, the solvent is a mixture of dimethyl sulfoxide and N,N-dimethylformamide.

[0017] According to some embodiments of the present invention, in the perovskite precursor solution, the concentration of the amino acid derivative additive is 25 mg / mol to 100 mg / mol.

[0018] According to some embodiments of the present invention, the steps include:

[0019] S1: Fluorine-doped tin oxide TCO glass or ITO glass is used as a substrate and subjected to UV and ozone cleaning and temperature treatment;

[0020] S2: spin-coating the cross-linked polymerized organic small molecules on the glass substrate treated in step S1, and annealing and cooling to room temperature for the first time to obtain a hole transport layer thin film;

[0021] S3: preparing the perovskite precursor solution, spin-coating the perovskite precursor solution onto the hole transport layer film, and annealing for the second time to form a perovskite layer;

[0022] S4: vapor-depositing a C60 film on the perovskite layer, atomically depositing a tin oxide film on the C60 film, and vapor-depositing a metal electrode on the tin oxide film.

[0023] In step S1:

[0024] The UV and ozone cleaning time can be 20 minutes.

[0025] The temperature range of the temperature treatment is 120-150°C and the time is 10-30 minutes.

[0026] In step S2:

[0027] According to some embodiments of the present invention, the cross-linked polymerized organic small molecule includes N4,N4'-di(naphthalene-1-yl)-N4,N4'-bis(4-vinylphenyl)biphenyl-4,4'-diamine.

[0028] Other hole transport layers such as SAM, NiO, PTAA or a combination of two hole transport layers can also be used for the preparation of perovskite thin film batteries. The corresponding reagent is MEO-2PACZ.

[0029] According to some embodiments of the present invention, the temperature of the first annealing is 100°C to 150°C.

[0030] According to some embodiments of the present invention, the first annealing time is 20 to 40 minutes.

[0031] In step S3:

[0032] According to some embodiments of the present invention, the temperature of the second annealing is 80°C to 120°C.

[0033] According to some embodiments of the present invention, the second annealing time is 20 to 40 minutes.

[0034] The solvent is a mixture of dimethyl sulfoxide and N,N-dimethylformamide in a volume ratio of 1:6.

[0035] The solvent is a mixture of dimethyl sulfoxide and N,N-dimethylformamide in a volume ratio of 1:6, which is conducive to the crystallization of perovskite.

[0036] The perovskite solar cell obtained by the preparation method of the present invention, when light is incident on the surface of the high perovskite solar cell, when the energy of the photon is greater than the band gap width of the perovskite material, the perovskite material is excited to generate carriers, and the free carriers are extracted through the built-in electric field formed by the heterojunction contact of the hole transport layer and the electron transport layer, and are transmitted to the conductive substrate and the metal electrode ends, thereby forming a photocurrent in the external circuit, thereby realizing solar power generation.

[0037] Fluorine-doped tin oxide glass is used as a conductive substrate, and the cross-linked polymerized organic small molecule N4,N4'-di(naphthalene-1-yl)-N4,N4'-bis(4-vinylphenyl)biphenyl-4,4'-diamine is used as a hole transport layer to extract holes and increase the interface connection effect, improve the energy level arrangement and enhance the stability.

[0038] Then, by adding different types of amino acid derivatives to the perovskite solution, the strongly coordinated amine groups and Lewis basic functional groups (such as nitrogen and oxygen) in the amino acid derivatives can form strong coordination with the perovskite, regulate crystal nucleation and growth, passivate lattice defects and stabilize the perovskite α phase; the side chains of aromatic amines are conducive to enhancing intermolecular stacking, forming an ordered and dense passivation interface layer at the perovskite grain boundary, improving the stability of the film and preventing the entry and decomposition of water, thereby achieving higher device efficiency and stability.

[0039] A second aspect of the present invention provides a perovskite solar cell prepared by the preparation method of the present invention.

[0040] One of the technical solutions of the present invention regarding perovskite solar cells has at least the following beneficial effects:

[0041] The perovskite solar cell of the present invention, by adding amino acid derivative additives, regulates the nucleation and crystal growth rates, forms a uniform and dense perovskite film, and improves the film quality of the absorption layer. This can improve light absorption and carrier transfer efficiency, thereby improving the conversion efficiency of the solar cell. The addition of amino acid derivatives can effectively passivate defects within the crystal and grain boundaries, reduce non-radiative recombination of carriers, and thus improve the photothermal stability of the solar cell. After photothermal stability testing, the device exhibited excellent long-term stability. Furthermore, after using the amino acid derivative additive, the open circuit voltage can be increased by about 50-100mV. This means that the improved cell can generate a higher voltage under the same lighting conditions, thereby improving the performance of the entire solar cell.

[0042] In the photothermal stability test, the test device showed excellent long-term stability, which indicates that the use of additives helps slow down the performance degradation of perovskite cells, enabling them to maintain a high performance level during long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the structure of a perovskite solar cell prepared according to an embodiment of the present invention.

[0044] Figure 2 These are the stability test results of the perovskite solar cells of the embodiments and comparative examples.

[0045] Figure 3 These are the cell efficiency test results of the perovskite solar cells of the embodiment and the comparative example. DETAILED DESCRIPTION

[0046] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0047] In a first aspect, some embodiments of the present invention provide a method for preparing a perovskite solar cell, the preparation method comprising adding an amino acid derivative additive to a perovskite precursor solution to improve the film quality of the perovskite absorption layer and passivate intracrystalline defects and grain boundaries, thereby improving the conversion efficiency and stability of the perovskite thin film battery, wherein the amino acid derivative additive comprises at least one of FMOC-D-valine, Fmoc-N-Me-L-valine, N-benzyloxycarbonyl-D-valine, benzoyl-DL-valine and L-valine.

[0048] It can be understood that the structural design and function of additives or ligands can effectively passivate various defects. By studying the relationship between the control of defects in perovskite films and stability by additives or ligands, it is helpful to solve the problem of stability of perovskite solar cells. In order to solve the problems of low efficiency and poor stability in existing perovskite thin film battery technology, the present invention uses additives containing amino acid derivatives to regulate nucleation and crystal growth rates, produce uniform and dense perovskite films, improve the film quality of the perovskite absorption layer, and effectively passivate defects within the crystal and at the grain boundaries, reduce non-radiative recombination of carriers, and improve battery efficiency and photothermal stability.

[0049] It should be noted that amino acid derivative additives are mainly used to improve the perovskite absorption layer in the perovskite thin film battery structure. This method is applicable to two commonly used perovskite thin film battery structures: NIP and PIN.

[0050] In the embodiments of the present invention, the description mainly takes the PIN structure as an example.

[0051] The introduction of amino acid derivatives into perovskite precursors is mainly to passivate defects in the functional groups of various derivatives, improve efficiency and stability, and form high-quality perovskite films. Specific beneficial effects also include:

[0052] The open circuit voltage increases by about 50-100mV;

[0053] Improved stability: After 500 hours of photothermal stability testing at 70°C in a nitrogen atmosphere under one sun, the stability results of the device showed that the device exhibited excellent long-term stability. The test results of the amino acid derivative structures with different designs showed that the retention rate of the original efficiency was greatly improved.

[0054] The structure of FMOC-D-valine is:

[0055]

[0056] The structure of Fmoc-N-Me-L-valine is:

[0057]

[0058] The structure of N-benzyloxycarbonyl-D-valine is:

[0059]

[0060] The structure of benzoyl-DL-valine is:

[0061]

[0062] The structure of L-valine is:

[0063]

[0064] In the first aspect, in some embodiments of the present invention, the components of the perovskite precursor solution include an amino acid derivative additive, a precursor, and a solvent.

[0065] In the first aspect, in some embodiments of the present invention, the precursor includes at least one of cesium iodide, lead iodide, methylammonium chloride, formamidine iodide, lead bromide, and methylammonium bromide.

[0066] In the first aspect, in some embodiments of the present invention, the solvent includes at least one of dimethyl sulfoxide and N,N-dimethylformamide.

[0067] In the first aspect, in some embodiments of the present invention, the solvent is a mixture of dimethyl sulfoxide and N,N-dimethylformamide.

[0068] In the first aspect, in some embodiments of the present invention, the concentration of the amino acid derivative additive in the perovskite precursor solution is 25 mg / mol to 100 mg / mol.

[0069] According to some embodiments of the present invention, the steps include:

[0070] S1: Fluorine-doped tin oxide TCO glass or ITO glass is used as a substrate and subjected to UV and ozone cleaning and temperature treatment;

[0071] S2: spin-coating the cross-linked polymerized organic small molecules on the glass substrate treated in step S1, and annealing and cooling to room temperature for the first time to obtain a hole transport layer thin film;

[0072] S3: preparing a perovskite precursor solution, spin-coating the perovskite precursor solution onto the hole transport layer film, and annealing the film for the second time to form a perovskite layer;

[0073] S4: vapor-depositing a C60 film on the perovskite layer, atomically depositing a tin oxide film on the C60 film, and vapor-depositing a metal electrode on the tin oxide film.

[0074] In step S1:

[0075] The UV and ozone cleaning time can be 20 minutes.

[0076] The temperature range of the temperature treatment is 120-150°C and the time is 10-30 minutes.

[0077] In step S2:

[0078] In the first aspect, in some embodiments of the present invention, the cross-linked polymerized organic small molecule includes N4,N4'-di(naphthalen-1-yl)-N4,N4'-bis(4-vinylphenyl)biphenyl-4,4'-diamine.

[0079] Other hole transport layers such as SAM, NiO, PTAA or a combination of two hole transport layers can also be used for the preparation of perovskite thin film batteries. The corresponding reagent is MEO-2PACZ.

[0080] In the first aspect, in some embodiments of the present invention, the temperature of the first annealing is 100°C to 150°C.

[0081] In the first aspect, in some embodiments of the present invention, the first annealing time is 20 to 40 minutes.

[0082] In step S3:

[0083] In the first aspect, in some embodiments of the present invention, the temperature of the second annealing is 80°C to 120°C.

[0084] In the first aspect, in some embodiments of the present invention, the second annealing time is 20 to 40 minutes.

[0085] The solvent is a mixture of dimethyl sulfoxide and N,N-dimethylformamide in a volume ratio of 1:6.

[0086] The solvent is a mixture of dimethyl sulfoxide and N,N-dimethylformamide in a volume ratio of 1:6, which is conducive to the crystallization of perovskite.

[0087] The perovskite solar cell obtained by the preparation method of the present invention, when light is incident on the surface of the high perovskite solar cell, when the energy of the photon is greater than the band gap width of the perovskite material, the perovskite material is excited to generate carriers, and the free carriers are extracted through the built-in electric field formed by the heterojunction contact of the hole transport layer and the electron transport layer, and are transmitted to the conductive substrate and the metal electrode ends, thereby forming a photocurrent in the external circuit, thereby realizing solar power generation.

[0088] Fluorine-doped tin oxide glass is used as a conductive substrate, and the cross-linked polymerized organic small molecule N4,N4'-di(naphthalene-1-yl)-N4,N4'-bis(4-vinylphenyl)biphenyl-4,4'-diamine is used as a hole transport layer to extract holes and increase the interface connection effect, improve the energy level arrangement and enhance the stability.

[0089] Then, by adding different types of amino acid derivatives to the perovskite solution, the strongly coordinated amine groups and Lewis basic functional groups (such as nitrogen and oxygen) in the amino acid derivatives can form strong coordination with the perovskite, regulate crystal nucleation and growth, passivate lattice defects and stabilize the perovskite α phase; the side chains of aromatic amines are conducive to enhancing intermolecular stacking, forming an ordered and dense passivation interface layer at the perovskite grain boundary, improving the stability of the film and preventing the entry and decomposition of water, thereby achieving higher device efficiency and stability.

[0090] It should be noted that if amino acids or amino acid derivatives are added after perovskite crystallization, they act as a surface passivation layer and cannot penetrate deep into the grain boundaries of the crystal. In the present invention, however, amino acids are used as bulk additives, added directly to the perovskite precursor solution to improve perovskite crystallization. This method reduces process complexity, improves process efficiency, and has higher repeatability than the effect of a passivation layer, making it more suitable for large-scale production applications in the future.

[0091] It should also be noted that, in one case, compared with a single N-benzyloxycarbonyl-D-valine, this application uses a comprehensive comparison of amino acid derivatives with multiple side chain groups. The effect of Fmoc-D-valine with an Fmoc group as the side chain on improving the Voc and stability of perovskite batteries is more significant, and the obtained improvement effect is more obvious and universal.

[0092] It should also be noted that another scenario is that if the polypeptide transport layer is placed at the lower interface of the perovskite absorber layer, this can only adjust the contact energy level of the interface and passivate the interface defects under the perovskite layer, but cannot effectively adjust the crystallization rate and material distribution of the perovskite absorber layer. The vertical distribution of the Cs element may be uneven, affecting the efficiency and stability of the battery. The present invention introduces amino acid derivatives into the absorber layer to regulate crystal growth and achieve uniform vertical distribution, resulting in better film quality. During actual battery operation, decomposition under photothermal conditions is less likely to occur, while also reducing process complexity and improving process efficiency.

[0093] In the above two cases, it is impossible to passivate the defects in the bulk phase and even to adjust the crystallization rate to form a better quality film. Only by improving the hydrophobicity and stability through surface treatment, and adjusting the interface energy level to improve the energy level alignment and increase Voc, the perovskite is easily decomposed under photothermal conditions. The different structural elements of the amino acid derivative additives in this application, including side chain length, side chain group and functional group, can have different effects on the photoelectric and chemical properties of the perovskite: the additives are directly incorporated into the bulk phase. First, the benzene ring and Fmoc group can intervene in the perovskite structure, regulate crystal growth, and passivate the ionic defects at the surface or grain boundary. Secondly, the high hydrophobicity of the benzene ring and Fmoc group can inhibit the formation of neutral iodine-related defects, and the π-conjugated structure is conducive to charge transfer and can increase Jsc. Thirdly, Lewis basic functional groups (such as nitrogen and oxygen) can improve the passivation of lead defects; and double bond vinyl groups and the like are significantly helpful for hydrophobicity; structures with electron-withdrawing ability, such as O atoms, can enhance electron delocalization and promote charge transfer. ─C═O and ─O groups can fix uncoordinated Pb 2+ Managing positively charged defects and N─H····I hydrogen bonds can compensate for formamidine vacancies and eliminate negatively charged defects.

[0094] It should also be noted that if amino acid ionic liquids are used as additives, PF6 - 、BF4 - The present invention does not introduce anionic groups, but instead introduces rigid side chain groups such as benzene rings and Fmoc. The role of these side groups is to improve the electronic structure of amino acid derivatives, thereby regulating crystal growth and improving film quality. The introduction of large side chain groups is very useful for improving defects and vacancies formed by PbI2, thereby improving the efficiency and photothermal stability of perovskite solar cells.

[0095] In combination with the second aspect, in some embodiments of the present invention, a perovskite solar cell is provided, which is prepared by the preparation method of the present invention.

[0096] It can be understood that the perovskite solar cell of the present invention, by adding amino acid derivative additives, regulates the nucleation and crystal growth rates, forms a uniform and dense perovskite film, and improves the film quality of the absorption layer. This can improve light absorption and carrier transfer efficiency, thereby improving the conversion efficiency of the solar cell. The addition of amino acid derivatives can effectively passivate defects within the crystal and grain boundaries, reduce non-radiative recombination of carriers, and thus improve the photothermal stability of the solar cell. After photothermal stability testing, the device exhibited excellent long-term stability. Furthermore, after using amino acid derivative additives, the open circuit voltage can be increased by about 50-100mV. This means that the improved cell can generate a higher voltage under the same lighting conditions, thereby improving the performance of the entire solar cell.

[0097] In the photothermal stability test, the test device showed excellent long-term stability, which indicates that the use of additives helps slow down the performance degradation of perovskite cells, enabling them to maintain a high performance level during long-term use.

[0098] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0099] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0100] Unless otherwise specified, "room temperature" in the present invention means 25°C±5°C.

[0101] Unless otherwise specified, “about” in the present invention means that the allowable error is within ±2%.

[0102] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0103] Example 1

[0104] A method for preparing a perovskite solar cell comprises the following steps:

[0105] S1: Prepare fluorine-doped tin oxide glass as a substrate, perform UV and ozone cleaning and temperature treatment;

[0106] S2: Spin-coating a cross-linked polymerized organic small molecule N4,N4'-di(naphthalene-1-yl)-N4,N4'-bis(4-vinylphenyl)biphenyl-4,4'-diamine on fluorine-doped tin oxide glass, followed by annealing and cooling to room temperature to obtain a hole transport layer film;

[0107] S3: preparing a perovskite solution, the perovskite solution including precursors: 0.112 mmol cesium iodide, 1.4 mmol lead iodide, 0.224 mmol methylammonium chloride, 1.288 mmol formamidine iodide, 0.112 mmol lead bromide, 0.224 mmol methylammonium bromide, solvents: dimethyl sulfoxide, N,N-dimethylformamide, introducing the additive FMOC-D-valine, spin coating the perovskite solution onto the hole transport layer and annealing to form a perovskite layer;

[0108] S4: vapor-depositing a C60 film on the perovskite layer, atomically depositing a tin oxide film on the C60 film, and vapor-depositing a metal electrode on the tin oxide film.

[0109] The structure of the prepared perovskite solar cell is as follows Figure 1 shown.

[0110] In step S1:

[0111] The UV and ozone cleaning time is 20 minutes.

[0112] The temperature of the temperature treatment is 150°C and the time is 30 minutes.

[0113] In step S2:

[0114] The temperature of the first annealing is 120° C. and the time of the first annealing is 20 min.

[0115] In step S3:

[0116] The temperature of the second annealing is 120° C. and the time of the second annealing is 30 min.

[0117] The solvent is a mixture of dimethyl sulfoxide and N,N-dimethylformamide in a volume ratio of 1:6.

[0118] The open circuit voltage of the invention is about 1.155V. After 1000 hours of light and heat stability test in a nitrogen atmosphere at 70°C under one sun, the stability test results of the device show that the device exhibits excellent long-term stability. According to the test results of FMOC-D-valine, its efficiency maintains about 90% of the original efficiency.

[0119] Example 2

[0120] A method for preparing a perovskite solar cell comprises the following steps:

[0121] A method for preparing an efficient and stable perovskite solar cell comprises the following steps:

[0122] S1: Prepare fluorine-doped tin oxide glass as a substrate, perform UV and ozone cleaning and temperature treatment;

[0123] S2: Spin-coating a cross-linked polymerized organic small molecule N4,N4'-di(naphthalene-1-yl)-N4,N4'-bis(4-vinylphenyl)biphenyl-4,4'-diamine on fluorine-doped tin oxide glass, followed by annealing and cooling to room temperature to obtain a hole transport layer film;

[0124] S3: preparing a perovskite solution, the perovskite solution including precursors: 0.112 mmol cesium iodide, 1.4 mmol lead iodide, 0.224 mmol methylammonium chloride, 1.288 mmol formamidine iodide, 0.112 mmol lead bromide, 0.224 mmol methylammonium bromide, solvents: dimethyl sulfoxide, N,N-dimethylformamide, introducing the additive Fmoc-N-Me-L-valine, spin-coating the perovskite solution onto the hole transport layer and annealing to form a perovskite layer;

[0125] S4: vapor-depositing a C60 film on the perovskite layer, atomically depositing a tin oxide film on the C60 film, and vapor-depositing a metal electrode on the tin oxide film.

[0126] In step S1:

[0127] The UV and ozone cleaning time is 20 minutes.

[0128] The temperature of the temperature treatment is 150°C and the time is 30 minutes.

[0129] In step S2:

[0130] The temperature of the first annealing is 120° C. and the time of the first annealing is 20 min.

[0131] In step S3:

[0132] The temperature of the second annealing is 120° C. and the time of the second annealing is 30 min.

[0133] The solvent is a mixture of dimethyl sulfoxide and N,N-dimethylformamide in a volume ratio of 1:6.

[0134] Compared with FMOC-D-valine in Example 1, one H atom in FMOC-D-valine is replaced by a methyl group, and the final open circuit voltage of the invention is about 1.154V. After 1000 hours of light and heat stability test at 70°C in a nitrogen atmosphere under one sun, the stability results of the test device show that the device exhibits long-term stability. According to the test results of Fmoc-N-Me-L-valine, its efficiency remains 88.5% of the original efficiency.

[0135] Example 3

[0136] A method for preparing a perovskite solar cell comprises the following steps:

[0137] A method for preparing an efficient and stable perovskite solar cell comprises the following steps:

[0138] S1: Prepare fluorine-doped tin oxide glass as a substrate, perform UV and ozone cleaning and temperature treatment;

[0139] S2: Spin-coating a cross-linked polymerized organic small molecule N4,N4'-di(naphthalene-1-yl)-N4,N4'-bis(4-vinylphenyl)biphenyl-4,4'-diamine on fluorine-doped tin oxide glass, followed by annealing and cooling to room temperature to obtain a hole transport layer film;

[0140] S3: preparing a perovskite solution, the perovskite solution including precursors: 0.112 mmol cesium iodide, 1.4 mmol lead iodide, 0.224 mmol methylammonium chloride, 1.288 mmol formamidine iodide, 0.112 mmol lead bromide, 0.224 mmol methylammonium bromide, solvents: dimethyl sulfoxide, N,N-dimethylformamide, introducing an additive N-benzyloxycarbonyl-D-valine, spin-coating the perovskite solution onto the hole transport layer and annealing to form a perovskite layer;

[0141] S4: vapor-depositing a C60 film on the perovskite layer, atomically depositing a tin oxide film on the C60 film, and vapor-depositing a metal electrode on the tin oxide film.

[0142] In step S1:

[0143] The UV and ozone cleaning time is 20 minutes.

[0144] The temperature of the temperature treatment is 150°C and the time is 30 minutes.

[0145] In step S2:

[0146] The temperature of the first annealing is 120° C. and the time of the first annealing is 20 min.

[0147] In step S3:

[0148] The temperature of the second annealing is 120° C. and the time of the second annealing is 30 min.

[0149] The solvent is a mixture of dimethyl sulfoxide and N,N-dimethylformamide in a volume ratio of 1:6.

[0150] Compared with FMOC-D-valine in Example 1, the main group in N-benzyloxycarbonyl-D-valine is a benzene ring, while the main group of FMOC-D-valine is an Fmoc group. Finally, the open circuit voltage of the invention is about 1.163V. After 1000 hours of light and heat stability test in a nitrogen atmosphere at 70°C under one sun, the stability results of the test device show that the device exhibits long-term stability. According to the test results of N-benzyloxycarbonyl-D-valine, its efficiency remains 96% of the original efficiency.

[0151] Example 4

[0152] A method for preparing a perovskite solar cell comprises the following steps:

[0153] A method for improving the efficiency and stability of a perovskite solar cell and a perovskite solar cell, comprising the following steps:

[0154] S1: Prepare fluorine-doped tin oxide glass as a substrate, perform UV and ozone cleaning and temperature treatment;

[0155] S2: Spin-coating a cross-linked polymerized organic small molecule N4,N4'-di(naphthalene-1-yl)-N4,N4'-bis(4-vinylphenyl)biphenyl-4,4'-diamine on fluorine-doped tin oxide glass, followed by annealing and cooling to room temperature to obtain a hole transport layer film;

[0156] S3: preparing a perovskite solution, the perovskite solution including precursors: 0.112 mmol cesium iodide, 1.4 mmol lead iodide, 0.224 mmol methylammonium chloride, 1.288 mmol formamidine iodide, 0.112 mmol lead bromide, 0.224 mmol methylammonium bromide, solvents: dimethyl sulfoxide, N,N-dimethylformamide, introducing an additive benzoyl-DL-valine, spin coating the perovskite solution onto the hole transport layer and annealing to form a perovskite layer;

[0157] S4: vapor-depositing a C60 film on the perovskite layer, atomically depositing a tin oxide film on the C60 film, and vapor-depositing a metal electrode on the tin oxide film.

[0158] In step S1:

[0159] The UV and ozone cleaning time is 20 minutes.

[0160] The temperature of the temperature treatment is 150°C and the time is 30 minutes.

[0161] In step S2:

[0162] The temperature of the first annealing is 120° C. and the time of the first annealing is 20 min.

[0163] In step S3:

[0164] The temperature of the second annealing is 120° C. and the time of the second annealing is 30 min.

[0165] The solvent is a mixture of dimethyl sulfoxide and N,N-dimethylformamide in a volume ratio of 1:6.

[0166] Compared with FMOC-D-valine in Example 1, the main group in benzoyl-DL-valine is a benzene ring, and the C atom linked to the benzene ring is also linked to an oxygen atom to form C=O, while the carbon atom linked to the Fmoc group in FMOC-D-valine forms a CO single bond with O. Finally, the open circuit voltage of the invention is about 1.154V. After 500 hours of light and heat stability test in a nitrogen atmosphere at 70°C under one sun, the stability results of the test device show that the device exhibits long-term stability. According to the test results of benzoyl-DL-valine, its efficiency remains 87% of the original efficiency.

[0167] Example 5

[0168] A method for preparing a perovskite solar cell comprises the following steps:

[0169] A method for improving the efficiency and stability of a perovskite solar cell and a perovskite solar cell, comprising the following steps:

[0170] S1: Prepare fluorine-doped tin oxide glass as a substrate, perform UV and ozone cleaning and temperature treatment;

[0171] S2: Spin-coating a cross-linked polymerized organic small molecule N4,N4'-di(naphthalene-1-yl)-N4,N4'-bis(4-vinylphenyl)biphenyl-4,4'-diamine on fluorine-doped tin oxide glass, followed by annealing and cooling to room temperature to obtain a hole transport layer film;

[0172] S3: preparing a perovskite solution, the perovskite solution including precursors: 0.112 mmol cesium iodide, 1.4 mmol lead iodide, 0.224 mmol methylammonium chloride, 1.288 mmol formamidine iodide, 0.112 mmol lead bromide, 0.224 mmol methylammonium bromide, solvents: dimethyl sulfoxide, N,N-dimethylformamide, introducing additives, the additive L-valine, spin coating the perovskite solution onto the hole transport layer and annealing to form a perovskite layer;

[0173] S4: vapor-depositing a C60 film on the perovskite layer, atomically depositing a tin oxide film on the C60 film, and vapor-depositing a metal electrode on the tin oxide film.

[0174] In step S1:

[0175] The UV and ozone cleaning time is 20 minutes.

[0176] The temperature of the temperature treatment is 150°C and the time is 30 minutes.

[0177] In step S2:

[0178] The temperature of the first annealing is 120° C. and the time of the first annealing is 20 min.

[0179] In step S3:

[0180] The temperature of the second annealing is 120° C. and the time of the second annealing is 30 min.

[0181] The solvent is a mixture of dimethyl sulfoxide and N,N-dimethylformamide in a volume ratio of 1:6.

[0182] Finally, the open circuit voltage of the invention was about 1.137V. After 1000 hours of light and heat stability test in a nitrogen atmosphere at 70°C under one sun, the stability test results of the device showed that the device exhibited long-term stability. According to the test results of L-valine, its efficiency remained at 78.2% of the original efficiency.

[0183] Comparative Example

[0184] A method for improving the efficiency and stability of a perovskite solar cell and a perovskite solar cell, comprising the following steps:

[0185] S1: Prepare fluorine-doped tin oxide glass as a substrate, perform UV and ozone cleaning and temperature treatment;

[0186] S2: Spin-coating a cross-linked polymerized organic small molecule N4,N4'-di(naphthalene-1-yl)-N4,N4'-bis(4-vinylphenyl)biphenyl-4,4'-diamine on fluorine-doped tin oxide glass, followed by annealing and cooling to room temperature to obtain a hole transport layer film;

[0187] S3: preparing a perovskite solution, the perovskite solution including precursors: 0.112 mmol cesium iodide, 1.4 mmol lead iodide, 0.224 mmol methylammonium chloride, 1.288 mmol formamidine iodide, 0.112 mmol lead bromide, 0.224 mmol methylammonium bromide, solvents: dimethyl sulfoxide, N,N-dimethylformamide, without adding valine derivatives, spin coating the perovskite solution onto the hole transport layer and annealing to form a perovskite layer;

[0188] S4: vapor-depositing a C60 film on the perovskite layer, atomically depositing a tin oxide film on the C60 film, and vapor-depositing a metal electrode on the tin oxide film.

[0189] In the control group, no valine derivative additive was added to the perovskite. The film obtained in this group had more defects, lower opening voltage and efficiency, and weaker stability than the group adding amino acid derivatives. Finally, the open circuit voltage of the invention was 1.139V. After 1000 hours of photothermal stability test in a nitrogen atmosphere at 70°C under one sun, the stability results of the test device showed that its efficiency remained at 64.5% of the original efficiency.

[0190] The performance of the perovskite solar cells prepared in Examples 1 to 5 and the comparative example was tested, and the results are shown in Table 1.

[0191] Table 1

[0192] Serial number PCE (%) <![CDATA[Jsc(mA / cm 2 )]]> Voc(V) FF Example 1 22.79473 23.71121 1.15572 83.69984 Example 2 22.43353 23.45853 1.15493 83.31815 Example 3 23.33476 24.06951 1.16381 83.82101 Example 4 21.89427 22.81336 1.15405 83.67833 Example 5 21.60051 23.36521 1.13792 81.74899 Comparative Example 21.40706 22.87558 1.13959 82.6296

[0193] As can be seen from Table 1, compared with the comparative example, after adding amino acid derivatives, Voc is improved, FF does not decrease, current transmission is improved, Jsc is increased, and overall PCE is improved to varying degrees.

[0194] The stability performance of the perovskite solar cells prepared in Examples 1 to 5 and the comparative example is shown in Table 2 and Figure 2 shown.

[0195] Table 2

[0196] Serial number 168h 336h 504h 672h 840h 1008h Comparative Example 82.09 78.91 74.02 68.88 65.99 64.53 Example 1 97.09 90.91 89.02 88.48 86.67 87.52 Example 2 98.32 93.21 88.21 90.53 88.87 88.54 Example 3 98.76 98.56 98.65 96.78 95.86 95.79 Example 4 95.34 93.67 90.78 88.34 87.63 86.48 Example 5 90.03 83.32 82.47 78.86 79.96 78.24

[0197] From Table 2 and Figure 2 It can be seen that after adding amino acid derivatives, the stability is improved to varying degrees.

[0198] The cell efficiency and Figure 3 shown.

[0199] from Figure 3 It can be seen that after adding amino acid derivatives, Voc is improved, which may be because the defects are passivated, the current transmission is improved, and Jsc is improved. Overall, PCE is improved to varying degrees.

[0200] The present invention has been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the spirit of the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that: The preparation method includes adding an amino acid derivative additive to a perovskite precursor solution to improve the film quality of the perovskite absorber layer and passivate intracrystalline defects and grain boundaries, thereby improving the conversion efficiency and stability of the perovskite thin film battery. The amino acid derivative additive includes at least one of FMOC-D-valine, Fmoc-N-Me-L-valine, N-benzyloxycarbonyl-D-valine, benzoyl-DL-valine and L-valine, and includes the following steps: S1: Fluorine-doped tin oxide TCO glass or ITO glass is used as a substrate and subjected to UV and ozone cleaning and temperature treatment; S2: spin-coating the cross-linked polymerized organic small molecules on the glass substrate treated in step S1, and annealing and cooling to room temperature for the first time to obtain a hole transport layer thin film; S3: preparing the perovskite precursor solution, spin-coating the perovskite precursor solution onto the hole transport layer film, and annealing for the second time to form a perovskite layer; S4: vapor-depositing a C60 film on the perovskite layer, atomically depositing a tin oxide film on the C60 film, and vapor-depositing a metal electrode on the tin oxide film.

2. The preparation method according to claim 1, characterized in that The components of the perovskite precursor solution include the amino acid derivative additive, a precursor and a solvent.

3. The preparation method according to claim 2, characterized in that The precursor includes at least one of cesium iodide, lead iodide, methylammonium chloride, formamidine iodide, lead bromide and methylammonium bromide.

4. The preparation method according to claim 2, characterized in that The solvent includes at least one of dimethyl sulfoxide and N,N-dimethylformamide.

5. The preparation method according to claim 2, characterized in that In the perovskite precursor solution, the concentration of the amino acid derivative additive is 25 mg / mol to 100 mg / mol.

6. The preparation method according to claim 1, characterized in that The cross-linked polymerized organic small molecules include N4,N4'-di(naphthalene-1-yl)-N4,N4'-bis(4-vinylphenyl)biphenyl-4,4'-diamine.

7. The preparation method according to claim 1, characterized in that The temperature of the first annealing is 100° C. to 150° C., and the time is 20 to 40 minutes.

8. The preparation method according to claim 1, characterized in that The second annealing temperature is 80° C. to 120° C., and the time is 20 to 40 minutes.

9. A perovskite solar cell, characterized in that: The method is prepared according to any one of claims 1 to 8.

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