Perovskite precursor solution, perovskite solar cell and preparation method thereof

Abstract

The invention discloses a perovskite precursor solution, a perovskite solar cell and a preparation method of the perovskite solar cell. The perovskite precursor solution comprises a metal halide, an organic halide, a solvent and a guanidine salt organic matter. The guanidine salt organic matter is composed of positive ions and negative ions, and the positive ions have the structure shown in the formula I (formula I); in the formula I, R1-R5 are the same or different and are independently selected from any one of hydrogen, halogen, hydroxyl, carboxyl, sulfydryl, amino, cyano, C1-C12 alkyl, trifluoromethyl, methoxyl, methylthio or methylamino; and the value range of n is 0-12. The guanidine salt organic matter can form a strong coordination bond with a metal halide, so that two-dimensional / quasi-two-dimensional perovskite is generated, non-radiative recombination and phase separation can be remarkably inhibited, deep passivation of defects is realized, in addition, the guanidine salt organic matter contains hydrophobic groups, moisture and oxygen can be effectively prevented from entering the perovskite light absorption layer, and the light absorption performance of the perovskite light absorption layer is improved. Therefore, the stability and efficiency of the device are improved.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, specifically relating to a perovskite precursor solution, a perovskite solar cell, and a method for preparing the same. Background Technology

[0002] Perovskite solar cells, with their advantages of high efficiency and low cost, have become a core development direction for next-generation photovoltaic technology. Among perovskite solar cells, wide-bandgap perovskite solar cells possess excellent photoelectric performance and tunable bandgap characteristics, showing broad application prospects in tandem cells and becoming a current research hotspot. However, wide-bandgap perovskite solar cells typically suffer from severe nonradiative recombination and phase separation problems, leading to open-circuit voltage loss and efficiency degradation.

[0003] To address the issues of non-radiative recombination and phase separation, related technologies typically involve adding ammonium salt compounds to perovskite materials. These ammonium salt compounds can react with metal ions (such as Pb) on the perovskite surface. 2+ Weak interactions can be formed to achieve surface passivation. However, the chemical structure and action mode of ammonium salt compounds are relatively simple, making it difficult to achieve deep passivation of defects, which in turn limits the improvement of device efficiency. At the same time, the poor hydrophobicity of ammonium salt compounds makes it impossible to effectively inhibit the corrosion of moisture and hydrogen, resulting in the difficulty in ensuring the long-term stability of the device. Summary of the Invention

[0004] This invention provides a perovskite precursor solution, a perovskite solar cell, and a method for preparing the same, in order to solve or alleviate the aforementioned technical problems. The perovskite precursor solution can significantly suppress nonradiative recombination and phase separation, achieve deep passivation of defects, improve device stability and efficiency, and enhance the hydrophobicity of the perovskite light-absorbing layer, thereby extending device lifetime.

[0005] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows: A first aspect of this invention provides a perovskite precursor solution comprising a metal halide, an organic halide, a solvent, and a guanidine salt organic compound; wherein the guanidine salt organic compound is composed of cations and anions, wherein the cations have the structure shown in Formula I: (Formula I); In Formula I, R1 to R5 may be the same or different, and each is independently selected from hydrogen, halogen, hydroxyl, carboxyl, mercapto, amino, cyano, C1 to C5. 12 Any one of alkyl, trifluoromethyl, methoxy, methylthio, or methylamino; the value of n ranges from 0 to 12.

[0006] As can be seen from the above technical solutions, the perovskite precursor solution provided in the first aspect of this invention allows the guanidine salt organic matter in the perovskite precursor solution to form strong coordination bonds with metal halides through guanidine groups and substituents, thereby generating two-dimensional / quasi-two-dimensional perovskites. These two-dimensional / quasi-two-dimensional perovskites can significantly suppress non-radiative recombination and phase separation, achieving deep passivation of defects and improving the stability and efficiency of the device. Furthermore, the guanidine salt organic matter contains hydrophobic groups, which can form a barrier layer with strong hydrophobic properties in humid environments, effectively blocking moisture and oxygen from entering the interior of the perovskite light-absorbing layer. This significantly improves the stability of the perovskite light-absorbing layer in humid environments and extends the device's lifespan.

[0007] A second aspect of the present invention provides a perovskite solar cell, comprising a substrate and a perovskite light-absorbing layer stacked together; the perovskite light-absorbing layer is formed by a perovskite precursor solution as described in the above embodiments.

[0008] As can be seen from the above technical solutions, the perovskite solar cell provided by the second aspect of the present invention has both excellent moisture resistance and structural stability because the perovskite light-absorbing layer is formed by the perovskite precursor solution of the above embodiments, thus significantly extending the life of the device while maintaining high efficiency.

[0009] A third aspect of the present invention provides a method for preparing a perovskite solar cell, comprising the following steps: providing a substrate; coating the substrate with a perovskite precursor solution of the above embodiment to form a perovskite light-absorbing layer.

[0010] As can be seen from the above technical solutions, the method for preparing perovskite solar cells provided by the third aspect of the present invention forms a perovskite light-absorbing layer by coating the substrate with the precursor solution of the above embodiment. The process is simple, has good repeatability, can be carried out in an atmospheric environment, and is suitable for large-scale preparation of high-performance and high-stability perovskite solar cells. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic flowchart of a method for fabricating perovskite solar cells according to some embodiments of the present invention; Figure 2 This is a schematic diagram of the device structure of the perovskite solar cell provided in Embodiment 1 of the present invention; Figure 3This is a schematic diagram of the device structure of the perovskite solar cell provided in Embodiment 3 of the present invention; Figure 4 This is the current density-voltage curve provided in Embodiment 1 of the present invention; Figure 5 This is the current density-voltage curve provided in Embodiment 2 of the present invention; Figure 6 These are the current density-voltage curves provided in Embodiments 3 and 4 of the present invention; Figure 7 This is the current density-voltage curve provided in Comparative Example 1; Figure 8 This is the current density-voltage curve provided in Comparative Example 2.

[0013] Explanation of reference numerals in the attached figures: 10 is a conductive substrate; 20 is a hole transport layer; 30 is a self-assembled monolayer; 40 is a perovskite light-absorbing layer; 50 is a passivation layer; 60 is an electron transport layer; 70 is a hole blocking layer; 80 is a metal electrode. 1 is a crystalline silicon bottom cell; 2 is a hole transport layer; 3 is a perovskite light-absorbing layer; 4 is a surface passivation layer; 5 is an electron transport layer; 6 is a buffer layer; 7 is a transparent conductive composite layer; 8 is a metal grid electrode; 9 is an anti-reflection layer. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the described order. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.

[0016] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0017] It should also be understood that the term “and / or” as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0018] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0019] This invention provides a perovskite precursor solution comprising a metal halide, an organic halide, a solvent, and a guanidine salt organic compound; the guanidine salt organic compound is composed of cations and anions, wherein the cations have the structure shown in Formula I: (Formula I); In Formula I, R1 to R5 may be the same or different, and each is independently selected from hydrogen, halogen, hydroxyl, carboxyl, mercapto, amino, cyano, C1 to C5. 12 Any one of alkyl, trifluoromethyl, methoxy, methylthio, or methylamino; n ranges from 0 to 12.

[0020] In this embodiment of the invention, metal halides are the basic materials for perovskite formation, providing metal ions and halide ions for the perovskite. Organic halides provide organic cations, modulating the perovskite band gap and promoting the formation of uniform, dense films. The solvent dissolves the metal halides, organic halides, and guanidine salt organic compounds, allowing the components to mix uniformly and form a homogeneous and stable precursor solution. The guanidine salt organic compounds react with the metal halides to generate two-dimensional / quasi-two-dimensional perovskites. This two-dimensional / quasi-two-dimensional perovskite can significantly suppress nonradiative recombination and phase separation, achieve deep passivation of defects, and enhance the hydrophobicity of the perovskite light-absorbing layer.

[0021] In some embodiments, the metal halide is selected from one or more of lead iodide (PbI₂), lead bromide (PbBr₂), lead chloride (PbCl₂), cesium iodide (CsI), cesium chloride (CsCl), and cesium bromide (CsBr). The organohalide is selected from one or more of formamidinium iodide (FAI), formamidinium bromide (FABr), formamidinium chloride (FACl), methylamine iodide (MAI), methylamine bromide (MABr), and methylamine chloride (MACl). The solvent is selected from N₂, N₂... Dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetonitrile, 2 One or more of methoxyethanol.

[0022] In some embodiments, R1 to R5 may be the same or different, and each is independently selected from any one of hydrogen, halogen, cyano, C1 to C5 alkyl or trifluoromethyl; the value of n ranges from 0 to 5. The halogen is selected from fluorine, chlorine, bromine or iodine.

[0023] These substituents have relatively small molecular weights and simple molecular structures, and they have good compatibility with metal halides. This helps to form a smooth perovskite light-absorbing layer, reducing light scattering and loss, thereby improving the overall device performance.

[0024] In some embodiments, the anion is selected from any one of halide ions, formate ions, acetate ions, hydrogen oxalate ions, nitrate ions, cyanate ions, oxocyanate ions, thiocyanate ions, tetrafluoroborate ions, or hexafluorophosphate ions. The halide ions are selected from fluoride ions, chloride ions, bromide ions, or iodide ions.

[0025] These anions can stably combine with guanidine salt cations to form guanidine salt organic compounds, without causing steric hindrance or charge interference to the dissolution of metal halides or the subsequent formation of perovskites.

[0026] In some embodiments, the guanidine salt organic compound is selected from one or more of 1-(4-chlorophenyl)guanidine hydrochloride, p-guanidinebenzonitrile hydrochloride, 1-(2-fluoro-5-(trifluoromethyl)phenyl)guanidine hydrochloride, 4-guanidinebenzoate, and 1-phenylguanidine nitrate.

[0027] First, these guanidine salt organic compounds can all react with metal ions (such as Pb) in metal halides via the guanidine group. 2+ First, coordination bonds are formed, leading to the formation of two-dimensional / quasi-two-dimensional perovskites. Second, substituents such as carboxyl, cyano, halogens (chlorine, fluorine), and phenyl can also participate in coordination, forming multiple coordination bonds in synergy with guanidine groups. This can significantly suppress nonradiative recombination and phase separation, achieving deep passivation of defects. Third, these guanidine salt organic compounds contain hydrophobic groups (such as cyano, halogens (chlorine, fluorine), phenyl), which can form a barrier layer with strong hydrophobic properties in humid environments. This effectively blocks moisture and oxygen from entering the interior of the perovskite light-absorbing layer, significantly improving the stability of the perovskite light-absorbing layer in humid environments and extending the device's lifespan.

[0028] In some embodiments, the mass ratio of guanidine salt organic compound to metal halide is 0.002 to 0.02, allowing the guanidine salt organic compound and metal halide to react sufficiently to generate two-dimensional / quasi-two-dimensional perovskites. If the mass ratio is greater than 0.02, excess guanidine salt organic compound may induce steric hindrance, hindering the formation of two-dimensional / quasi-two-dimensional perovskites; if the mass ratio is less than 0.002, the guanidine group and substituents cannot sufficiently form multiple coordination bonds with the metal ions, making it difficult to achieve deep passivation of perovskite defects. Exemplarily, the mass ratio of guanidine salt organic compound to metal halide can be any typical but non-limiting value such as 0.002, 0.003, 0.005, 0.008, 0.01, 0.011, 0.014, 0.015, 0.017, 0.019, 0.02, or any range between any two values.

[0029] In some embodiments, the mass concentration of the guanidine salt organic compound in the perovskite precursor solution is 0.5 mg / mL to 5 mg / mL. Within this concentration range, the guanidine salt organic compound exhibits good dispersion stability and can be thoroughly mixed with the metal halide and solvent. If the mass concentration is greater than 5 mg / mL, the homogeneity and fluidity of the solution will deteriorate, making it difficult to form a smooth perovskite light-absorbing layer. If the mass concentration is less than 0.5 mg / mL, an effective concentration cannot be formed in the solution, resulting in insufficient formation of two-dimensional / quasi-two-dimensional perovskite. Exemplarily, the mass concentration of the guanidine salt organic compound can be any typical but non-limiting value, such as 0.5 mg / mL, 0.8 mg / mL, 1 mg / mL, 1.2 mg / mL, 1.5 mg / mL, 1.8 mg / mL, 2 mg / mL, 2.5 mg / mL, 3 mg / mL, 3.5 mg / mL, 4 mg / mL, 4.5 mg / mL, or 5 mg / mL, or a range between any two values.

[0030] As can be seen from the above technical solution, the perovskite precursor solution provided by this invention allows the guanidine salt organic matter in the perovskite precursor solution to form strong coordination bonds with metal halides through guanidine groups and substituents, thereby generating two-dimensional / quasi-two-dimensional perovskites. These two-dimensional / quasi-two-dimensional perovskites can significantly suppress non-radiative recombination and phase separation, achieving deep passivation of defects and improving the stability and efficiency of the device. Furthermore, the guanidine salt organic matter contains hydrophobic groups, which can form a barrier layer with strong hydrophobic properties in humid environments, effectively blocking moisture and oxygen from entering the perovskite light-absorbing layer. This significantly improves the stability of the perovskite light-absorbing layer in humid environments and extends the device's lifespan.

[0031] This invention provides a perovskite solar cell, which includes a substrate and a perovskite light-absorbing layer stacked together; wherein the perovskite light-absorbing layer is formed by a perovskite precursor solution as described in the above embodiment.

[0032] In this embodiment of the invention, the perovskite solar cell can be a single-layer or stacked perovskite solar cell.

[0033] In a single-layer perovskite solar cell, the complete structure includes a stacked conductive substrate, a hole transport layer, a self-assembled monolayer, a perovskite light-absorbing layer, a passivation layer, an electron transport layer, a hole-blocking layer, and a metal electrode. In a tandem perovskite solar cell, the complete structure includes a stacked crystalline silicon substrate, a hole transport layer, a perovskite light-absorbing layer, a surface passivation layer, an electron transport layer, a buffer layer, a transparent conductive composite layer, metal grid electrodes, and an anti-reflection layer.

[0034] In some embodiments, the perovskite light-absorbing layer comprises a two-dimensional / quasi-two-dimensional perovskite. The two-dimensional / quasi-two-dimensional perovskite is formed by coordination bonding between guanidine salt organic matter and metal halides, which can effectively suppress ion migration, significantly suppress non-radiative recombination and phase separation, achieve deep passivation of defects, and improve the performance and stability of perovskite solar cells.

[0035] In some embodiments, the band gap of the perovskite light-absorbing layer is 1.65 eV to 1.77 eV, which enables efficient absorption of visible light from sunlight and improves the photoelectric conversion efficiency of the battery. For example, the band gap of the perovskite light-absorbing layer can be any typical but non-limiting value such as 1.65 eV, 1.66 eV, 1.68 eV, 1.7 eV, 1.72 eV, 1.75 eV, or 1.77 eV, or a range between any two values.

[0036] As can be seen from the above technical solutions, the perovskite solar cell provided by the present invention has excellent moisture resistance and structural stability because the perovskite light-absorbing layer is formed by the perovskite precursor solution of the above embodiments, thus significantly extending the life of the device while maintaining high efficiency.

[0037] Please see Figure 1 This invention provides a method for preparing a perovskite solar cell, specifically including steps S101 to S102.

[0038] Step S101: Provide a substrate.

[0039] For a single-layer perovskite solar cell, providing a substrate includes preparing a conductive substrate, forming a hole transport layer on the conductive substrate, and forming a self-assembled monolayer on the hole transport layer.

[0040] The steps for preparing the conductive substrate include: placing the conductive substrate (such as an ITO or FTO transparent conductive glass substrate) in an ultrasonic cleaner and sequentially ultrasonically cleaning it with detergent, deionized water, acetone, and isopropanol. After cleaning, the conductive substrate is placed in an oven to dry at a temperature of 60℃~80℃. Before use, the conductive substrate is subjected to ultraviolet ozone treatment for 10min~20min.

[0041] The steps for forming a hole transport layer on a conductive substrate include: weighing 5 mg to 15 mg of hole transport layer material (such as NiO). XThe hole transport layer material solution is dissolved in 1 mL of solvent (such as deionized water) and ultrasonically dispersed for 10 min to 20 min. The dispersed hole transport layer material solution is then dropped onto a conductive substrate in a fume hood and spin-coated at a rate of 2000 rpm to 3000 rpm for 30 s to 45 s. After spin-coating, the substrate is annealed at 120 ℃ to 160 ℃ on a hot plate for 10 min to 40 min to form a hole transport layer with a thickness of 5 nm to 15 nm on the conductive substrate. The substrate is then immediately transferred to a glove box under a nitrogen atmosphere.

[0042] The steps for forming a self-assembled monolayer on the hole transport layer include: dissolving 0.3 mg to 1.5 mg of a self-assembled monolayer material (such as [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz) or [4-(7H-dibenzocarbazole-7-yl)butyl]phosphonic acid (4PADCB)) in 1 mL of solvent (such as ethanol or isopropanol); dropping the self-assembled monolayer material solution onto the hole transport layer; spin-coating at 2000 rpm to 4000 rpm for 20 s to 60 s; and annealing at 100 °C to 120 °C for 10 to 20 min, thereby forming a self-assembled monolayer on the hole transport layer with a thickness of 0.5 nm to 1 nm.

[0043] For tandem perovskite solar cells, providing a substrate includes preparing a crystalline silicon base cell and forming a hole transport layer on the crystalline silicon base cell.

[0044] The steps for preparing a crystalline silicon solar cell include: cleaning the crystalline silicon solar cell with ethanol, drying it with nitrogen after cleaning, and subjecting it to ultraviolet ozone treatment for 10 to 20 minutes before use.

[0045] The steps for forming a hole transport layer on a crystalline silicon solar cell include: dissolving a hole transport layer material (such as [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz)) at a concentration of 0.3 mg / mL to 1.0 mg / mL in a solvent (such as ethanol); applying the hole transport layer material solution onto the crystalline silicon solar cell using a spin coating speed of 4000 rpm to 6000 rpm for 30 s to 60 s; and then thermally annealing the solution at 90℃ to 110℃ for 10 min to 20 min to form a hole transport layer with a thickness of 0.5 nm to 1 nm on the crystalline silicon solar cell.

[0046] Step S102: Coat the substrate with a perovskite precursor solution to form a perovskite light-absorbing layer.

[0047] The preparation steps of the perovskite precursor solution include: weighing metal halide, organic halide and guanidine salt organic compound, dissolving the metal halide and organic halide in a solvent, adding guanidine salt organic compound, stirring continuously for 2h~4h, and filtering with a polytetrafluoroethylene filter membrane with a filter diameter of 0.22μm before use to obtain the perovskite precursor solution.

[0048] For monolayer perovskite solar cells, the steps for forming a perovskite light-absorbing layer on a self-assembled monolayer include: dropping a perovskite precursor solution onto the self-assembled monolayer, and spin-coating in two stages. In the first stage, the spin speed is 1000 rpm to 3000 rpm and the spin-coating time is 10 s to 30 s. In the second stage, the spin speed is 5000 rpm to 7000 rpm and the spin-coating time is 20 s to 30 s. 10 s to 15 s before the end of the second step, 120 μL to 200 μL of antisolvent (such as ethyl acetate or chlorobenzene) is dropped on. After spin-coating, the layer is annealed at 100℃ to 120℃ for 10 min to 30 min, thereby forming a perovskite light-absorbing layer with a thickness of 400 nm to 800 nm on the self-assembled monolayer.

[0049] After forming a perovskite light-absorbing layer on a self-assembled monolayer, the preparation steps also include: forming a passivation layer on the perovskite light-absorbing layer, forming an electron transport layer on the passivation layer, forming a hole blocking layer on the electron transport layer, and forming a metal electrode on the hole blocking layer.

[0050] The steps for forming a passivation layer on the perovskite light-absorbing layer include: dissolving 0.5 mg to 2 mg of passivation layer material (such as 1,3-propanediamine hydroiodate) in 1 mL of solvent (such as isopropanol); dropping the passivation layer material solution onto the perovskite light-absorbing layer; spin-coating at a speed of 3000 rpm to 6000 rpm for 30 s to 60 s; and thermally annealing at 100 °C to 120 °C for 5 min to 10 min, thereby forming a passivation layer with a thickness of 0.5 nm to 1 nm on the perovskite light-absorbing layer.

[0051] The steps of forming an electron transport layer on the passivation layer include: applying an electron transport layer material (such as fullerene (C)) to the passivation layer. 60 The powder is placed in a high-vacuum thermal evaporation coating machine, and the substrate with the passivation layer is transferred into the evaporation chamber. The system background vacuum level is then lowered to below 5 × 10⁻⁶. -4 After Pa, by controlling the evaporation source current, a thin film is thermally evaporated on the passivation layer at a deposition rate of 0.5 Å / s to 1.5 Å / s, thereby forming an electron transport layer on the passivation layer with a thickness of 1 nm to 40 nm.

[0052] The steps for forming a hole-blocking layer on the electron transport layer include: after forming the electron transport layer, under the same vacuum conditions, replacing the evaporation source with a hole-blocking layer material (such as copper oxychloride (BCP) powder), and waiting until the system's background vacuum level is lower than 5 × 10⁻⁶.-4 After Pa, a thin film is thermally evaporated at a rate of 0.3 Å / s to 0.8 Å / s to form a hole blocking layer on the electron transport layer with a thickness of 6 nm to 10 nm.

[0053] The steps for forming a metal electrode on a hole-blocking layer include: placing the substrate on which the hole-blocking layer is formed in a high-vacuum thermal evaporation coating machine, replacing the evaporation source with a metal electrode material (such as high-purity copper (Cu) or silver (Ag) particles), and waiting until the system's background vacuum level is lower than 5 × 10⁻⁶. -4 After Pa, by controlling the evaporation source current, an electrode layer is thermally evaporated at a deposition rate of 0.5 Å / s to 2.5 Å / s, thereby forming a metal electrode on the hole blocking layer with a thickness of 80 nm to 200 nm.

[0054] For tandem perovskite solar cells, the steps for forming a perovskite light-absorbing layer on the hole transport layer include: dropping a perovskite precursor solution onto the hole transport layer, and spin-coating in two stages. In the first stage, the spin speed is 1000 rpm to 3000 rpm and the spin-coating time is 5 s to 15 s; in the second stage, the spin speed is 5000 rpm to 7000 rpm and the spin-coating time is 20 s to 40 s. 10 s to 15 s before the end of the second step, 300 μL to 500 μL of antisolvent (such as chlorobenzene) is dropped. After spin-coating, the cells are annealed at 100℃ to 120℃ for 15 min to 25 min, thereby forming a perovskite light-absorbing layer on the hole transport layer with a thickness of 500 nm to 1000 nm.

[0055] After forming a perovskite light-absorbing layer on the hole transport layer, the fabrication steps further include: forming a surface passivation layer on the perovskite light-absorbing layer, forming an electron transport layer on the surface passivation layer, forming a buffer layer on the electron transport layer, forming a transparent conductive composite layer on the buffer layer, forming a metal grid electrode on the transparent conductive composite layer, and forming an anti-reflection layer on the metal grid electrode.

[0056] The steps for forming a surface passivation layer on the perovskite light-absorbing layer include: dissolving a surface passivation layer material (such as phenylethylammonium iodide (PEAI) or its analogues) at a concentration of 0.3 mg / mL to 1.0 mg / mL in a solvent (such as isopropanol); dropping the surface passivation layer material solution onto the perovskite light-absorbing layer; spin-coating at a speed of 4000 rpm to 6000 rpm for 20 s to 40 s; and thermally annealing at 100℃ to 120℃ for 5 min to 10 min, thereby forming a surface passivation layer on the perovskite light-absorbing layer with a thickness of 0.5 nm to 1 nm.

[0057] The steps for forming an electron transport layer on the surface passivation layer include: depositing an electron transport layer material (such as fullerene (C40 ... 60A thin film is formed on the surface passivation layer, thereby forming an electron transport layer with a thickness of 10nm~15nm.

[0058] The steps for forming a buffer layer on the electron transport layer include: depositing a buffer layer material (such as tin oxide (SnO2)) thin film on the electron transport layer using atomic layer deposition (ALD) to form a buffer layer with a thickness of 10 nm to 15 nm.

[0059] The steps for forming a transparent conductive composite layer on the buffer layer include: depositing a thin film of transparent conductive composite material (indium zinc oxide (IZO)) on the buffer layer using magnetron sputtering, thereby forming a transparent conductive composite layer with a thickness of 30 nm to 50 nm on the buffer layer.

[0060] The steps for forming metal gate electrodes on a transparent conductive composite layer include: using a high-precision mask, depositing metal gate lines (such as silver gate lines) on the transparent conductive composite layer by thermal evaporation, with a gate line thickness of 450nm~550nm and a gate line width of 30μm~50μm.

[0061] The steps for forming an antireflection layer on a metal gate electrode include: depositing a thin film of an antireflection layer material (such as magnesium fluoride (MgFx)) on the metal gate electrode using a thermal evaporation method, thereby forming an antireflection layer on the metal gate electrode with a thickness of 100 nm to 150 nm.

[0062] As can be seen from the above technical solutions, the method for preparing perovskite solar cells provided by the present invention forms a perovskite light-absorbing layer by coating the substrate with the precursor solution of the above embodiment. The process is simple, has good repeatability, can be carried out in an atmospheric environment, and is suitable for large-scale preparation of high-performance and high-stability perovskite solar cells.

[0063] The following detailed description of the perovskite precursor solution, perovskite solar cell, and preparation method provided by the present invention, through specific embodiments and experimental data, is provided in detail.

[0064] Example 1 like Figure 2 As shown, this embodiment provides a perovskite solar cell, which is a single-layer perovskite solar cell. The specific structure includes a conductive substrate 10, a hole transport layer 20, a self-assembled monolayer 30, a perovskite light-absorbing layer 40, a passivation layer 50, an electron transport layer 60, a hole blocking layer 70, and a metal electrode 80 stacked together.

[0065] Please see Figure 1 The specific method for fabricating perovskite solar cells is as follows: The steps for preparing the conductive substrate 10 include: placing the conductive substrate 10 (ITO transparent conductive glass substrate) in an ultrasonic cleaning instrument and sequentially using detergent, deionized water, acetone, and isopropanol for ultrasonic cleaning; after cleaning, placing the conductive substrate 10 in an oven to dry at a temperature of 70°C. Before use, the conductive substrate 10 is subjected to ultraviolet ozone treatment for 15 minutes.

[0066] The step of forming a hole transport layer 20 on the conductive substrate 10 includes: weighing 10 mg of NiO X Nanoparticles were dissolved in 1 mL of deionized water and ultrasonically dispersed for 15 min. The dispersed NiO was then placed in a fume hood. X The nanoparticle solution was dropped onto the conductive substrate 10 and spin-coated at a rate of 2500 rpm for 40 s. After spin-coating, the substrate was annealed at 120 °C for 30 min on a hot plate to form a hole transport layer 20 with a thickness of 5 nm on the conductive substrate 10. After the spin-coating was completed, the substrate was immediately transferred to a glove box under a nitrogen atmosphere.

[0067] The steps for forming a self-assembled monolayer 30 on the hole transport layer 20 include: dissolving 0.5 mg MeO-4PACz in 1 mL of ethanol, adding the MeO-4PACz solution dropwise onto the hole transport layer 20, spin-coating at 3000 rpm for 40 s, and annealing at 100 °C for 15 min, thereby forming a self-assembled monolayer 30 with a thickness of 0.5 nm on the hole transport layer 20.

[0068] The preparation steps of the perovskite precursor solution include: weighing 18.2 mg CsI, 192.7 mg PbBr2, 423.6 mg PbI2, 33.4 mg MAI, and 192.6 mg FAI, dissolving these substances in 800 μL DMF and 200 μL DMSO, adding 5 mg 1-(4-chlorophenyl)guanidine hydrochloride, stirring continuously for 3 h, and filtering with a 0.22 μm polytetrafluoroethylene filter membrane before use to obtain the perovskite precursor solution.

[0069] The steps for forming a perovskite light-absorbing layer 40 on the self-assembled monolayer 30 include: dropping a perovskite precursor solution onto the self-assembled monolayer 30, and spin-coating in two stages. In the first stage, the spin speed is 1000 rpm and the spin-coating time is 10 s. In the second stage, the spin speed is 6000 rpm and the spin-coating time is 30 s. 150 μL of the anti-solvent chlorobenzene is dropped 10 s before the end of the second step. After spin-coating, the layer is annealed at 100 °C for 20 min, thereby forming a perovskite light-absorbing layer 40 with a thickness of 600 nm on the self-assembled monolayer 30.

[0070] The steps for forming a passivation layer 50 on the perovskite light-absorbing layer 40 include: dissolving 1 mg of 1,3-propanediamine hydroiodate in 1 mL of isopropanol, adding the 1,3-propanediamine hydroiodate solution dropwise onto the perovskite light-absorbing layer 40, spin-coating at 4000 rpm for 40 s, and then heat-annealing at 100 °C for 10 min to form a passivation layer 50 with a thickness of 0.5 nm on the perovskite light-absorbing layer 40.

[0071] The step of forming an electron transport layer 60 on the passivation layer 50 includes: applying a fullerene (C) 60 The powder is placed in a high-vacuum thermal evaporation coating machine, and the substrate with the passivation layer 50 is transferred into the evaporation chamber. The system background vacuum level is lower than 5 × 10⁻⁶. -4 After Pa, by controlling the evaporation source current, a thin film is thermally evaporated on the passivation layer 50 at a deposition rate of 1 Å / s, thereby forming an electron transport layer 60 with a thickness of 10 nm on the passivation layer 50.

[0072] The step of forming a hole-blocking layer 70 on the electron transport layer 60 includes: after forming the electron transport layer 60, under the same vacuum conditions, replacing the evaporation source with copper bath powder (BCP), and waiting until the system's background vacuum is lower than 5 × 10⁻⁶. -4 After Pa, a thin film is thermally evaporated at a rate of 0.5 Å / s to form a hole blocking layer 70 with a thickness of 6 nm on the electron transport layer 60.

[0073] The steps for forming the metal electrode 80 on the hole blocking layer 70 include: placing the substrate on which the hole blocking layer 70 is formed in a high-vacuum thermal evaporation coating machine, replacing the evaporation source with high-purity silver (Ag) particles, and waiting until the system's background vacuum level is lower than 5 × 10⁻⁶. - 4 After Pa, by controlling the evaporation source current, an electrode layer is thermally evaporated at a deposition rate of 1 Å / s, thereby forming a metal electrode 80 with a thickness of 80 nm on the hole blocking layer 70.

[0074] Example 2 The perovskite solar cell of Example 2 was prepared according to the preparation method of Example 1, except that: The preparation steps of the perovskite precursor solution include: weighing 18.2 mg CsI, 192.7 mg PbBr2, 423.6 mg PbI2, 33.4 mg MAI, and 192.6 mg FAI, dissolving these substances in 800 μL DMF and 200 μL DMSO, adding 5 mg p-guanidinobenzonitrile hydrochloride, stirring continuously for 3 h, and filtering with a 0.22 μm polytetrafluoroethylene filter membrane before use to obtain the perovskite precursor solution.

[0075] Example 3 like Figure 3 As shown, this embodiment provides a perovskite solar cell, which is a stacked perovskite solar cell. The specific structure includes a crystalline silicon base cell 1, a hole transport layer 2, a perovskite light-absorbing layer 3, a surface passivation layer 4, an electron transport layer 5, a buffer layer 6, a transparent conductive composite layer 7, a metal grid electrode 8, and an anti-reflection layer 9, all stacked together.

[0076] Please see Figure 1 The specific method for fabricating perovskite solar cells is as follows: The steps for preparing the crystalline silicon bottom cell 1 include: cleaning the crystalline silicon bottom cell 1 with ethanol, drying it with nitrogen after cleaning, and subjecting the crystalline silicon bottom cell 1 to ultraviolet ozone treatment for 15 minutes before use.

[0077] The steps for forming a hole transport layer 2 on a crystalline silicon bottom cell 1 include: dissolving 0.5 mg / mL MeO-4PACz in 1 mL of ethanol, coating the MeO-4PACz solution onto the crystalline silicon bottom cell 1 by spin coating at 5000 rpm for 40 s, and then thermally annealing at 100 °C for 15 min to form a hole transport layer 2 with a thickness of 0.5 nm on the crystalline silicon bottom cell 1.

[0078] The preparation steps of the perovskite precursor solution include: weighing 18.2 mg CsI, 192.7 mg PbBr2, 423.6 mg PbI2, 33.4 mg MAI, and 192.6 mg FAI, dissolving these substances in 800 μL DMF and 200 μL DMSO, adding 5 mg 1-(4-chlorophenyl)guanidine hydrochloride, stirring continuously for 3 h, and filtering with a 0.22 μm polytetrafluoroethylene filter membrane before use to obtain the perovskite precursor solution.

[0079] The steps for forming a perovskite light-absorbing layer 3 on the hole transport layer 2 include: dropping a perovskite precursor solution onto the hole transport layer 2, and spin-coating in two stages. In the first stage, the spin speed is 1000 rpm and the spin-coating time is 10 s; in the second stage, the spin speed is 6000 rpm and the spin-coating time is 30 s. 10 s before the end of the second step, 400 μL of the anti-solvent chlorobenzene is dropped. After spin-coating, the layer is annealed at 100 °C for 20 min, thereby forming a perovskite light-absorbing layer 3 with a thickness of 800 nm on the hole transport layer 2.

[0080] The steps for forming a surface passivation layer 4 on the perovskite light-absorbing layer 3 include: dissolving 0.5 mg / mL phenylethyl ammonium iodide (PEAI) in isopropanol, adding the PEAI solution dropwise onto the perovskite light-absorbing layer 3, spin-coating at 6000 rpm for 30 s, and thermally annealing at 100 °C for 10 min, thereby forming a surface passivation layer 4 with a thickness of 0.5 nm on the perovskite light-absorbing layer 3.

[0081] The step of forming an electron transport layer 5 on the surface passivation layer 4 includes: depositing a fullerene (C4) layer on the surface passivation layer 4 using a thermal evaporation method. 60 A thin film is formed on the surface passivation layer 4, thereby forming an electron transport layer 5 with a thickness of 10 nm.

[0082] The step of forming a buffer layer 6 on the electron transport layer 5 includes: depositing a tin oxide (SnO2) thin film on the electron transport layer 5 using atomic layer deposition (ALD) to form a buffer layer 6 with a thickness of 10 nm on the electron transport layer 5.

[0083] The step of forming a transparent conductive composite layer 7 on the buffer layer 6 includes: depositing a thin film of indium zinc oxide (IZO) on the buffer layer 6 by magnetron sputtering, thereby forming a transparent conductive composite layer 7 with a thickness of 30 nm on the buffer layer 6.

[0084] The step of forming a metal gate electrode 8 on the transparent conductive composite layer 7 includes: using a high-precision mask, depositing silver gate lines on the transparent conductive composite layer 7 by thermal evaporation, with a gate line thickness of 450 nm and a gate line width of 30 μm.

[0085] The step of forming an antireflection layer 9 on the metal gate electrode 8 includes: depositing a magnesium fluoride (MgFx) thin film on the metal gate electrode 8 by thermal evaporation, thereby forming an antireflection layer 9 on the metal gate electrode 8 with a thickness of 100 nm.

[0086] Example 4 The perovskite solar cell of Example 4 was prepared according to the preparation method of Example 3, except that: The preparation steps of the perovskite precursor solution include: weighing 18.2 mg CsI, 192.7 mg PbBr2, 423.6 mg PbI2, 33.4 mg MAI, and 192.6 mg FAI, dissolving these substances in 800 μL DMF and 200 μL DMSO, adding 5 mg p-guanidinobenzonitrile hydrochloride, stirring continuously for 3 h, and filtering with a 0.22 μm polytetrafluoroethylene filter membrane before use to obtain the perovskite precursor solution.

[0087] Comparative Example 1 The perovskite solar cell of Comparative Example 1 was prepared according to the preparation method of Example 1, except that the preparation steps of the perovskite precursor solution included: weighing 18.2 mg CsI, 192.7 mg PbBr2, 423.6 mg PbI2, 33.4 mg MAI, and 192.6 mg FAI, dissolving these substances in 800 μL DMF and 200 μL DMSO, stirring continuously for 3 h, and filtering with a polytetrafluoroethylene filter membrane with a filter diameter of 0.22 μm before use to obtain the perovskite precursor solution.

[0088] Comparative Example 2 The perovskite solar cell of Comparative Example 2 was prepared according to the preparation method of Example 3, except that the preparation steps of the perovskite precursor solution included: weighing 18.2 mg CsI, 192.7 mg PbBr2, 423.6 mg PbI2, 33.4 mg MAI, and 192.6 mg FAI, dissolving these substances in 800 μL DMF and 200 μL DMSO, stirring continuously for 3 h, and filtering with a polytetrafluoroethylene filter membrane with a filter diameter of 0.22 μm before use to obtain the perovskite precursor solution.

[0089] Test data results At a light intensity of 100 mW / cm 2 Under AM 1.5G simulated sunlight irradiation, current density-voltage curves were scanned and recorded for Examples 1-4 and Comparative Examples 1-2. The results are shown in Table 1 and... Figures 4-8 As shown.

[0090] Table 1 Parameters of Perovskite Solar Cell Devices

[0091] Through Table 1 and Figures 4-8 It can be seen that, compared with Comparative Example 1, Examples 1-2 have higher photoelectric conversion efficiency, and the open-circuit voltage, short-circuit current density and fill factor are all improved. Similarly, compared with Comparative Example 2, Examples 3-4 also show higher photoelectric conversion efficiency, and the open-circuit voltage, short-circuit current density and fill factor are also improved. This indicates that guanidine salt organic matter can significantly improve the stability of the perovskite light-absorbing layer, effectively reduce the defect state density, and improve the performance of perovskite solar cell devices.

[0092] In summary, in the embodiments of the present invention, guanidine salt organic materials (such as 1-(4-chlorophenyl)guanidine hydrochloride or p-guanidine benzonitrile hydrochloride) contain hydrophobic groups (such as phenyl, chlorine atoms or cyano groups), which can form a barrier layer with strong hydrophobic properties in a humid environment, effectively blocking moisture and oxygen from entering the interior of the perovskite light-absorbing layer, significantly improving the stability of the perovskite light-absorbing layer in a humid environment and extending the life of the device; in addition, the guanidine groups and substituents of the guanidine salt organic materials can form strong coordination bonds with metal halides, thereby generating two-dimensional / quasi-two-dimensional perovskites. These two-dimensional / quasi-two-dimensional perovskites can significantly suppress nonradiative recombination and phase separation, achieve deep passivation of defects, and improve the stability and efficiency of the device.

Claims

1. A perovskite precursor solution, characterized in that, Including metal halides, organohalides, solvents, and guanidine salts of organic compounds; The guanidine salt organic compound is composed of cations and anions, wherein the cations have the structure shown in Formula I: (Formula I); In Formula I, R1 to R5 may be the same or different, and each is independently selected from hydrogen, halogen, hydroxyl, carboxyl, mercapto, amino, cyano, C1 to C5. 12 Any one of alkyl, trifluoromethyl, methoxy, methylthio, or methylamino; the value of n ranges from 0 to 12.

2. The perovskite precursor solution according to claim 1, characterized in that, R1 to R5 may be the same or different, and each is independently selected from any one of hydrogen, halogen, cyano, C1 to C5 alkyl or trifluoromethyl; the value of n ranges from 0 to 5.

3. The perovskite precursor solution according to claim 1, characterized in that, The anion is selected from any one of the following: halide ion, formate ion, acetate ion, hydrogen oxalate ion, nitrate ion, cyanate ion, oxocyanate ion, thiocyanate ion, tetrafluoroborate ion, or hexafluorophosphate ion.

4. The perovskite precursor solution according to claim 1, characterized in that, The guanidine salt organic compound is selected from one or more of 1-(4-chlorophenyl)guanidine hydrochloride, p-guanidinebenzonitrile hydrochloride, 1-(2-fluoro-5-(trifluoromethyl)phenyl)guanidine hydrochloride, 4-guanidinebenzoate, and 1-phenylguanidine nitrate.

5. The perovskite precursor solution according to claim 1, characterized in that, The mass ratio of the guanidine salt organic compound to the metal halide is 0.002 to 0.

02.

6. The perovskite precursor solution according to claim 1, characterized in that, In the perovskite precursor solution, the mass concentration of the guanidine salt organic compound is 0.5 mg / mL to 5 mg / mL.

7. A perovskite solar cell, characterized in that, Includes a substrate and a perovskite light-absorbing layer stacked together; The perovskite light-absorbing layer is formed by a perovskite precursor solution as described in any one of claims 1-6.

8. The perovskite solar cell according to claim 7, characterized in that, The perovskite light-absorbing layer comprises two-dimensional / quasi-two-dimensional perovskite.

9. The perovskite solar cell according to claim 7, characterized in that, The band gap of the perovskite light-absorbing layer is 1.65 eV to 1.77 eV.

10. A method for preparing a perovskite solar cell, characterized in that, Includes the following steps: Provide a base; A perovskite precursor solution as described in any one of claims 1-6 is coated on the substrate to form a perovskite light-absorbing layer.

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