Perovskite solar cell and design method of interface fusion layer thereof

Abstract

The invention discloses a perovskite solar cell and a design method of an interface fusion layer thereof, and belongs to the field of photovoltaic technology. The solar cell comprises an electron transport layer, an interface fusion layer, a perovskite thin film, a hole transport layer and an electrode which are stacked, wherein the interface fusion layer is of an organic-inorganic hybrid perovskite structure formed by reaction of an organic compound in the electron transport layer and lead iodide in the perovskite thin film. The organic-inorganic hybrid perovskite structure formed by the reaction of the organic compound in the electron transport layer and the lead iodide in the perovskite thin film is arranged between the electron transport layer and the perovskite thin film, so that the bonding toughness can be enhanced, and the generation of transverse cracks in the mechanical bending process can be effectively inhibited; and the mechanical stability of the flexible perovskite solar cell machinery is improved.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic technology, specifically relating to a design method for a perovskite solar cell and its interface fusion layer. Background Technology

[0002] Perovskite solar cells have seen rapid development in the photovoltaic field in recent years due to their excellent light absorption, high carrier mobility, long diffusion distance, and low-cost solution processing characteristics, and have broad application prospects.

[0003] In existing technologies, such as a method for stabilizing the perovskite / hole transport layer interface using multi-toothed chelate biomaterials and a method for fabricating a formal photovoltaic device (CN117545285A), a carbon-based perovskite solar cell based on interface engineering strategy and its fabrication method (CN118660464A), a method for fabricating a perovskite solar cell with a directional interface modification layer (CN119365042A), a perovskite solar cell and its fabrication method, photovoltaic system (CN119343021A), and a perovskite solar cell (CN119604118A), the perovskite thin film, especially the interface between it and the electron transport layer, is prone to cracking during mechanical bending, resulting in poor mechanical stability of flexible perovskite devices and thus reducing their service life. Summary of the Invention

[0004] The purpose of this application is to provide a design method for perovskite solar cells and their interface fusion layer, which can solve the problem of poor mechanical stability of current perovskite solar cells.

[0005] In a first aspect, embodiments of this application provide a perovskite solar cell, comprising an electron transport layer, an interface fusion layer, a perovskite thin film, a hole transport layer, and an electrode stacked together. The interface fusion layer is an organic-inorganic hybrid perovskite structure formed by the reaction of an organic compound in the electron transport layer with lead iodide in the perovskite thin film.

[0006] Optionally, the organic compound includes one of the following: phenethylammonium iodide, benzylammonium iodide, methylammonium hydroiodate, and formamidinium hydroiodate.

[0007] Secondly, embodiments of this application provide a method for designing an interface fusion layer for a perovskite solar cell, the method comprising:

[0008] An organic compound and a tin oxide nanocrystal solution are mixed to obtain a first solvent. The organic compound can react with lead iodide to form an organic-inorganic hybrid perovskite structure.

[0009] An electron transport layer is prepared based on the first solvent;

[0010] A perovskite precursor solution is spin-coated onto the electron transport layer to form a perovskite film and an interface fusion layer located between the electron transport layer and the perovskite film. The interface fusion layer is formed by the reaction of the organic compound and lead iodide in the perovskite film.

[0011] The perovskite solar cell is obtained by stacking the electron transport layer, the interface fusion layer, the perovskite thin film, the hole transport layer, and the electrode layer.

[0012] Optionally, the organic compound includes one of the following: phenethylammonium iodide, benzylammonium iodide, methylammonium hydroiodate, and formamidinium hydroiodate.

[0013] Optionally, the preparation of the electron transport layer based on the first solvent includes:

[0014] The first solvent is added dropwise to a flexible conductive substrate;

[0015] The first solvent on the surface of the flexible conductive substrate is spin-coated under a first rotation speed condition, and a first annealing is performed after spin-coating to obtain the electron transport layer. The spin-coating duration is 25s-35s, and the first rotation speed is 2400rpm-2600rpm.

[0016] Optionally, the temperature range of the first annealing is 100℃-120℃, and the duration of the first annealing is 1h-2h.

[0017] Optionally, the step of spin-coating the perovskite precursor solution onto the electron transport layer to form a perovskite thin film and an interface fusion layer located between the electron transport layer and the perovskite thin film includes:

[0018] The perovskite precursor solution is dropped into the electron transport layer;

[0019] The perovskite precursor solution on the surface of the electron transport layer is spin-coated for the first time under a second rotation speed condition, the second rotation speed being 800 rpm-1200 rpm, and the duration of the first spin coating being 6 s-10 s.

[0020] The perovskite precursor solution on the surface of the electron transport layer is spin-coated a second time under a third rotation speed condition, wherein the third rotation speed is 3500 rpm-4500 rpm and the duration of the second spin coating is 25 s-35 s.

[0021] The electron transport layer after the second spin coating is annealed to form the perovskite thin film and the interface fusion layer on the electron transport layer.

[0022] Optionally, before annealing the electron transport layer after the second spin coating to form the perovskite film and the interface fusion layer on the electron transport layer, the method further includes:

[0023] Within 8-12 seconds before the end of the second spin coating process, an antisolvent, anisole, is dropped onto the coating surface of the electron transport layer.

[0024] Optionally, annealing the electron transport layer after the second spin coating to form the perovskite thin film and the interface fusion layer on the electron transport layer includes:

[0025] The electron transport layer after the second spin coating is annealed in a first temperature range to form the perovskite film and the interface fusion layer on the electron transport layer. The first temperature range is 100℃-120℃.

[0026] Optionally, the volume ratio between dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in the perovskite precursor solution is 4:1 to 9:1.

[0027] In this embodiment, the presence of an organic-inorganic hybrid perovskite structure formed by the reaction of organic compounds in the electron transport layer with lead iodide in the perovskite film between the electron transport layer and the perovskite film enhances the bonding toughness, effectively suppresses the generation of transverse cracks during mechanical bending, and improves the mechanical stability of the flexible perovskite solar cell. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic diagram illustrating the improvement in cell efficiency of the perovskite solar cell provided in this application embodiment compared to existing solar cells;

[0030] Figure 2 The improved mechanical bending stability of the perovskite solar cell provided in this application embodiment compared to existing solar cells;

[0031] Figure 3 This is one of the schematic flowcharts of the fabrication method of the perovskite solar cell provided in the embodiments of this application;

[0032] Figure 4This is a second schematic flowchart illustrating the fabrication method of the perovskite solar cell provided in the embodiments of this application.

[0033] Figure 5 This is a schematic diagram of the structure of a perovskite solar cell provided in an embodiment of this application. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0035] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0036] This application provides a perovskite solar cell, comprising a stacked electron transport layer, an interface fusion layer, a perovskite thin film, a hole transport layer, and electrodes. The interface fusion layer is an organic-inorganic hybrid perovskite structure formed by the reaction of an organic compound in the electron transport layer with lead iodide in the perovskite thin film. The organic compound can be any of all substances capable of reacting with lead iodide to form an organic-inorganic hybrid perovskite structure.

[0037] like Figure 1 As shown, the upper lines represent embodiments of this application, and the lower lines represent comparative examples without an interface fusion layer. The comparison yields the content shown in Table 1 below.

[0038]

[0039] Table 1

[0040] By introducing a low-dimensional perovskite interface fusion layer at the electron transport layer / perovskite thin film interface, the crystallinity of the bottom of the perovskite layer is improved, the interface defect states are reduced, the device turn-on voltage is significantly improved, and the efficiency of the flexible perovskite solar cell is increased from 18.9% to 21.0%.

[0041] like Figure 2As shown, the upper lines represent embodiments of this application, while the lower lines represent comparative examples without an interface fusion layer. The comparison reveals that by introducing a low-dimensional perovskite interface fusion layer at the electron transport layer / perovskite thin film interface, the interface adhesion toughness is enhanced, effectively suppressing the generation of transverse cracks during mechanical bending, thus improving the mechanical bending stability of the flexible perovskite solar cell. The flexible perovskite solar cell device, after being bent 2000 times at a 5mm radius of curvature, can maintain 96% of its initial efficiency (compared to only 57% in the comparative example).

[0042] In this embodiment, the presence of an organic-inorganic hybrid perovskite structure formed by the reaction of organic compounds in the electron transport layer with lead iodide in the perovskite film between the electron transport layer and the perovskite film enhances the bonding toughness, effectively suppresses the generation of transverse cracks during mechanical bending, and improves the mechanical stability of the flexible perovskite solar cell.

[0043] Optionally, the organic compound includes one of the following: phenylethylammonium iodide, benzylammonium iodide, methylammonium hydroiodate, and formamidinium hydroiodate. This embodiment provides a variety of substances that can react with lead iodide to form an organic-inorganic hybrid perovskite structure, which is equivalent to providing multiple methods for preparing the interface fusion layer. In actual production, multiple production methods can be adopted simultaneously according to needs and available materials, thereby improving production efficiency.

[0044] This application also provides a method for designing an interface fusion layer for perovskite solar cells, such as... Figure 3 As shown, it includes the following steps:

[0045] Step 101: Mix the organic compound and the tin oxide nanocrystal solution to obtain the first solvent. The organic compound can react with lead iodide to form an organic-inorganic hybrid perovskite structure.

[0046] Step 102: Prepare an electron transport layer based on the first solvent;

[0047] Step 103: Spin-coating the perovskite precursor solution onto the electron transport layer to form a perovskite film and an interface fusion layer located between the electron transport layer and the perovskite film. The interface fusion layer is formed by the reaction of the organic compound and lead iodide in the perovskite film.

[0048] Step 104: The electron transport layer, the interface fusion layer, the perovskite thin film, the hole transport layer, and the electrode layer are stacked together to obtain the perovskite solar cell.

[0049] In this embodiment, the electron transport layer is prepared using a first solvent, which includes an organic compound that can react with lead iodide to form an organic-inorganic hybrid perovskite structure. After spin-coating a perovskite precursor solution onto the electron transport layer, a perovskite thin film and an interface fusion layer between the electron transport layer and the perovskite thin film are formed. Subsequently, a hole transport layer and an electrode are stacked with the electron transport layer, the interface fusion layer, and the perovskite thin film to obtain a perovskite solar cell. Because of the organic-inorganic hybrid perovskite structure formed by the reaction of the organic compound in the electron transport layer with lead iodide in the perovskite thin film between the electron transport layer and the perovskite thin film, the bonding toughness is enhanced, effectively suppressing the generation of transverse cracks during mechanical bending, and improving the mechanical stability of the flexible perovskite solar cell.

[0050] Optionally, the organic compound includes one of the following: phenethylammonium iodide, benzylammonium iodide, methylammonium hydroiodate, and formamidinium hydroiodate.

[0051] The content of this embodiment has been described in the above embodiments and descriptions of perovskite solar cells, and will not be repeated here.

[0052] Optionally, the preparation of the electron transport layer based on the first solvent includes:

[0053] The first solvent is added dropwise to a flexible conductive substrate;

[0054] The first solvent on the surface of the flexible conductive substrate is spin-coated under a first rotation speed condition, and a first annealing is performed after spin-coating to obtain the electron transport layer. The spin-coating duration is 25s-35s, and the first rotation speed is 2400rpm-2600rpm.

[0055] In this embodiment, after the first solvent is dropped onto the flexible conductive substrate (PEN-ITO), the first solvent is spin-coated onto the surface of the flexible conductive substrate at a first rotation speed. The spin-coating duration is 25s-35s to ensure that the first solvent is evenly distributed on the flexible conductive substrate, so that the surface thickness of the electron transport layer formed subsequently is uniform and the properties of each area of ​​the surface are consistent.

[0056] Optionally, the temperature range of the first annealing is 100℃-120℃, and the duration of the first annealing is 1h-2h. In this embodiment, under the above annealing conditions, the annealing effect can be improved, promoting the crystallization of the first solvent, enhancing the fluidity of the material, filling the microscopic defects caused by spin coating, and improving the performance of the electron transport layer.

[0057] Optionally, the step of spin-coating the perovskite precursor solution onto the electron transport layer to form a perovskite thin film and an interface fusion layer located between the electron transport layer and the perovskite thin film includes:

[0058] The perovskite precursor solution is dropped into the electron transport layer;

[0059] The perovskite precursor solution on the surface of the electron transport layer was first spin-coated under a second rotation speed of 800 rpm-1200 rpm, and the duration of the first spin-coating was 6 s-10 s.

[0060] The perovskite precursor solution on the surface of the electron transport layer is spin-coated a second time under a third rotation speed condition, wherein the third rotation speed is 3500 rpm-4500 rpm and the duration of the second spin coating is 25 s-35 s.

[0061] The electron transport layer after the second spin coating is annealed to form the perovskite thin film and the interface fusion layer on the electron transport layer.

[0062] In this embodiment, after the perovskite precursor solution is added to the electron transport layer, two spin coating processes are performed. The first spin coating lasts for 6-10 seconds at a rotation speed of 800-1200 rpm, forming the substrate portion of the perovskite film. The second spin coating lasts for 25-35 seconds at a rotation speed of 3500-4500 rpm, ensuring the perovskite precursor solution is uniformly distributed in the electron transport layer. After both spin coating processes, annealing is performed to remove solvent residues and promote the crystallization of the perovskite precursor solution, forming the perovskite film. Lead iodide in the perovskite film can react with organic compounds in the electron transport layer to form an organic-inorganic hybrid perovskite structure, resulting in an interface fusion layer. Because the materials are thoroughly spin-coated during the formation of both the electron transport layer and the perovskite film, the thickness and properties of both the electron transport layer and the perovskite film remain uniform, resulting in a uniform and smooth interface fusion layer that avoids unevenness that could reduce mechanical stability.

[0063] Optionally, before annealing the electron transport layer after the second spin coating to form the perovskite film and the interface fusion layer on the electron transport layer, the method further includes:

[0064] Within 8-12 seconds before the end of the second spin coating process, an antisolvent, anisole, is dropped onto the coating surface of the electron transport layer.

[0065] In this embodiment, the perovskite precursor solution includes a main solvent (such as DMF or DMSO) and a solute (such as the perovskite precursor). Anisole, an antisolvent, is added during the second spin coating process. Anisole has limited miscibility with the main solvent, but it can quickly extract the main solvent, causing the solute to reach a supersaturated state instantly, promoting uniform nucleation. In other words, it can suppress random nucleation, reduce grain boundary defects, and form a dense, large-grained thin film, thereby enhancing the photoelectric properties of the light absorption layer.

[0066] Optionally, annealing the electron transport layer after the second spin coating to form the perovskite thin film and the interface fusion layer on the electron transport layer includes:

[0067] The electron transport layer, after the second spin coating, is annealed in a first temperature range of 100°C-120°C to form the perovskite thin film and the interface fusion layer. Annealing under these conditions effectively promotes the crystallization of the perovskite precursor solution, thus forming the perovskite thin film.

[0068] Optionally, the volume ratio of dimethylformamide (DMF) to dimethyl sulfoxide (DMSO) in the perovskite precursor solution is from 4:1 to 9:1. Under these DMF to DMSO volume ratios, the solute in the perovskite precursor solution can be fully dissolved, facilitating subsequent reactions with other materials.

[0069] Please see further. Figure 4 , combined Figure 4 The fabrication process of the electron transport layer, interface fusion layer, perovskite thin film, optical transport layer and electrode is described.

[0070] Preparation of SnO2 nanocrystals: 5g SnCl4·5H2O was dissolved in 40mL ethylene glycol and stirred overnight. Then, 10mL of the above solution was transferred to a 100mL round-bottom flask, and 2mL of acetic acid and ammonia solution, and 1mL of tetramethylammonium hydroxide solution were added with stirring. After cooling to room temperature, the round-bottom flask was placed in an oil bath and heated at 150℃ for 30min. Then, ethanol was added for dispersion, and the supernatant was discarded after centrifugation. The precipitate was then dispersed again with ethanol. The mixture was centrifuged twice at 2500rpm (25min each time) and twice at 5000rpm (5min each time). Finally, the precipitate obtained by centrifugation was dispersed in about 30mL of ethanol to obtain a SnO2 nanocrystal solution with a concentration of 12.5mg / mL.

[0071] Fabrication of the interface fusion layer:

[0072] 1. Preparation of SnO2 electron transport layer containing PEAI: 0.5 mg of PEAI was weighed into 1 mL of ethanol dispersion of SnO2 nanocrystals, and after ultrasonic homogenization, it was spin-coated onto a PEN-ITO substrate at 2500 rpm for 30 s, and annealed at 105 °C for 1.5 h to obtain SnO2 electron transport layer.

[0073] 2. Preparation of perovskite thin films: 1.28 mmol PbI₂, 0.067 mmol PbCl₂, 1.08 mmol FAI, 0.067 mmol FABr, and 0.2 mmol CsI were weighed and dissolved in 1 mL of solvent (DMF:DMSO volume ratio 4:1) to prepare a precursor solution, which was stirred for 2 h. The solution was then filtered through a 0.22 μm polytetrafluoroethylene (PTFE) membrane for later use. The perovskite precursor solution was spin-coated onto the surface of the SnO₂ electron transport layer at 1000 rpm for 8 s, followed by 4000 rpm for 30 s. Approximately 10 s before the end of the spin-coating process, 110 μL of the antisolvent anisole was rapidly added dropwise. The solution was then transferred to a hot plate and annealed at 110 °C for 15 min.

[0074] Through the above two steps, a low-dimensional perovskite interface fusion layer can be formed at the interface between the electron transport layer and the perovskite layer, as follows: Figure 5 As shown.

[0075] Preparation of the Spiro-OMeTAD hole transport layer: 72.3 mg of Spiro-OMeTAD powder was dissolved in 1 mL of chlorobenzene, and 28.8 μL of 4-tert-butylpyridine and 17.5 μL of lithium salt solution (520 mg dissolved in 1 mL of acetonitrile) were added. The mixture was stirred overnight. After filtering through a 0.22 μm polytetrafluoroethylene membrane, the solution was spin-coated onto the surface of a perovskite film at 4000 rpm for 30 s. The film was then stored overnight in a dehumidifier to oxidize Spiro-OMeTAD and improve its hole mobility.

[0076] Au electrode fabrication: Vacuuming to <10⁻⁴ Pa, gold plating rate The coating thickness is approximately 80 nm.

[0077] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0078] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A perovskite solar cell, characterized in that, The solar cell includes an electron transport layer, an interface fusion layer, a perovskite thin film, a hole transport layer, and electrodes stacked together. The interface fusion layer is an organic-inorganic hybrid perovskite structure formed by the reaction of an organic compound in the electron transport layer with lead iodide in the perovskite thin film.

2. The perovskite solar cell as described in claim 1, characterized in that, The organic compound includes one of the following: phenylethylammonium iodide, phenylmethylammonium iodide, methylammonium hydroiodate, and formamidinium hydroiodate.

3. A method for designing an interface fusion layer for a perovskite solar cell, characterized in that, The method includes: An organic compound and a tin oxide nanocrystal solution are mixed to obtain a first solvent. The organic compound can react with lead iodide to form an organic-inorganic hybrid perovskite structure. An electron transport layer is prepared based on the first solvent; A perovskite precursor solution is spin-coated onto the electron transport layer to form a perovskite film and an interface fusion layer located between the electron transport layer and the perovskite film. The interface fusion layer is formed by the reaction of the organic compound and lead iodide in the perovskite film. The perovskite solar cell is obtained by stacking the electron transport layer, the interface fusion layer, the perovskite thin film, the hole transport layer, and the electrode layer.

4. The method as described in claim 3, characterized in that, The organic compound includes one of the following: phenylethylammonium iodide, phenylmethylammonium iodide, methylammonium hydroiodate, and formamidinium hydroiodate.

5. The method as described in any one of claims 3 or 4, characterized in that, The preparation of the electron transport layer based on the first solvent includes: The first solvent is added dropwise to a flexible conductive substrate; The first solvent on the surface of the flexible conductive substrate is spin-coated under a first rotation speed condition, and a first annealing is performed after spin-coating to obtain the electron transport layer. The spin-coating duration is 25s-35s, and the first rotation speed is 2400rpm-2600rpm.

6. The method as described in claim 5, characterized in that, The temperature range of the first annealing is 100℃-120℃, and the duration of the first annealing is 1h-2h.

7. The method as described in any one of claims 3 or 4, characterized in that, The process of spin-coating a perovskite precursor solution onto the electron transport layer to form a perovskite thin film and an interface fusion layer located between the electron transport layer and the perovskite thin film includes: The perovskite precursor solution is dropped into the electron transport layer; The perovskite precursor solution on the surface of the electron transport layer is spin-coated for the first time under a second rotation speed condition, the second rotation speed being 800 rpm-1200 rpm, and the duration of the first spin coating being 6 s-10 s. The perovskite precursor solution on the surface of the electron transport layer is spin-coated a second time under a third rotation speed condition, wherein the third rotation speed is 3500 rpm-4500 rpm and the duration of the second spin coating is 25 s-35 s. The electron transport layer after the second spin coating is annealed to form the perovskite thin film and the interface fusion layer on the electron transport layer.

8. The method as described in claim 7, characterized in that, Before annealing the electron transport layer after the second spin coating to form the perovskite film and the interface fusion layer on the electron transport layer, the method further includes: Within 8-12 seconds before the end of the second spin coating process, an antisolvent, anisole, is dropped onto the coating surface of the electron transport layer.

9. The method as described in claim 7, characterized in that, The step of annealing the electron transport layer after the second spin coating to form the perovskite thin film and the interface fusion layer on the electron transport layer includes: The electron transport layer after the second spin coating is annealed in a first temperature range to form the perovskite film and the interface fusion layer on the electron transport layer. The first temperature range is 100℃-120℃.

10. The method as described in any one of claims 3 or 4, characterized in that, The volume ratio of dimethylformamide (DMF) to dimethyl sulfoxide (DMSO) in the perovskite precursor solution is from 4:1 to 9:1.

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