Photovoltaic cell and method for producing a photovoltaic cell, photovoltaic module

Abstract

The application relates to a photovoltaic cell and a preparation method thereof, and a photovoltaic module. The photovoltaic cell comprises a substrate structure, a hole transport layer, a hole extraction layer and a perovskite layer which are sequentially stacked; the material of the hole transport layer comprises nickel oxide; and the material of the hole extraction layer comprises 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene). In the photovoltaic cell, the hole extraction layer can make the energy levels between the perovskite layer and the hole transport layer more matched, thereby improving the carrier transport rate, reducing non-radiative recombination, and improving the conversion efficiency of the photovoltaic cell.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to photovoltaic cells and their preparation methods, and photovoltaic modules. Background Technology

[0002] Perovskite photovoltaic cells are a type of photovoltaic cell that uses perovskite structure materials as the core light-absorbing layer. Due to their high efficiency, low cost, and ease of fabrication, they are considered one of the most industrially promising photovoltaic technologies after crystalline silicon cells. In perovskite photovoltaic cells, sunlight irradiates the perovskite layer, and its band gap causes electrons to jump from the valence band to the conduction band, generating free electrons and holes. The electron transport layer (ETL) selectively extracts electrons from the conduction band, and the hole transport layer (HTL) selectively extracts holes from the valence band, preventing electron-hole recombination.

[0003] In traditional perovskite photovoltaic cells, the energy level matching between the hole transport layer and the perovskite layer is poor, resulting in a low carrier transport rate and an increase in non-radiative recombination, which in turn affects the conversion efficiency of the photovoltaic cell. Summary of the Invention

[0004] Therefore, it is necessary to provide photovoltaic cells, their fabrication methods, and photovoltaic modules. In the photovoltaic cell of this application, the hole extraction layer enables a better match between the energy levels of the perovskite layer and the hole transport layer, thereby increasing the carrier transport rate, reducing non-radiative recombination, and improving the conversion efficiency of the photovoltaic cell.

[0005] In a first aspect, this application provides a photovoltaic cell, comprising a substrate structure, a hole transport layer, a hole extraction layer, and a perovskite layer stacked sequentially; the hole transport layer is made of nickel oxide; the hole extraction layer is made of 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene).

[0006] In some embodiments, the mass ratio of poly(3-(4-carboxybutyl)thiophene) to 1,3,5-tribromobenzene in the 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) is (8~20):1.

[0007] In some embodiments, the material of the hole extraction layer further includes nanoparticles; the nanoparticles include at least one of alumina nanoparticles, magnesium oxide nanoparticles, and silicon oxide nanoparticles.

[0008] In some embodiments, the mass ratio of the 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) to the nanoparticles is (50~1000):1.

[0009] In some embodiments, the substrate structure includes a silicon substrate battery structure and a first transparent conductive layer stacked together; the first transparent conductive layer is disposed between the silicon substrate battery structure and the hole transport layer.

[0010] In some embodiments, the surface where the silicon-based battery structure contacts the first transparent conductive layer is textured.

[0011] In some embodiments, the thickness of the hole extraction layer is 2nm to 50nm.

[0012] In some embodiments, the thickness of the hole transport layer is 1 nm to 15 nm.

[0013] In some embodiments, the thickness of the hole transport layer is 1 nm to 2 nm.

[0014] Secondly, this application provides a method for preparing a photovoltaic cell, comprising the following steps:

[0015] Provide the base structure;

[0016] A hole transport layer is prepared on the surface of the substrate structure, wherein the material of the hole transport layer includes nickel oxide;

[0017] A hole extraction layer is prepared on the surface of the hole transport layer away from the substrate structure, and the material of the hole extraction layer includes 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene);

[0018] A perovskite layer is prepared on the surface of the hole extraction layer that is away from the hole transport layer.

[0019] In some embodiments, the method for preparing the hole extraction layer includes the following steps:

[0020] A solution of poly(3-(4-carboxybutylthiophene) doped with 1,3,5-tribromobenzene is applied to the surface of the hole transport layer away from the substrate structure to form a liquid film;

[0021] The liquid film is then annealed.

[0022] Thirdly, this application provides a photovoltaic module, comprising:

[0023] Cover plate;

[0024] At least one battery string, the battery string comprising the photovoltaic cell described in any one of the above-mentioned methods, or the photovoltaic cell prepared by the method described in any one of the above-mentioned methods;

[0025] And an encapsulation layer, which is located between the cover plate and the battery string, and the cover plate is connected to the battery string through the encapsulation layer.

[0026] The aforementioned photovoltaic cell includes a hole extraction layer disposed between a hole transport layer and a perovskite layer. The hole transport layer is made of nickel oxide, and the hole extraction layer is made of 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene). Poly(3-(4-carboxybutyl)thiophene) is a polymer with a conjugated structure containing carboxybutyl side chains, enabling the 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) to have good anchoring ability on the nickel oxide surface. The valence band top energy level of the perovskite material is typically between -5.4 eV and -5.6 eV, with an offset of over 0.6 eV between it and the nickel oxide hole transport layer. Undoped poly(3-(4-carboxybutyl)thiophene) has a higher valence band top energy level, resulting in poorer energy level matching with the perovskite material and a higher hole extraction barrier. Poly(3-(4-carboxybutyl)thiophene), as a conjugated polymer, possesses electron-donating properties in its thiophene units. The bromine atoms in the 1,3,5-tribromobenzene molecule are strong electron-withdrawing groups, which can extract electrons from the thiophene backbone of poly(3-(4-carboxybutyl)thiophene) through charge transfer. This transforms poly(3-(4-carboxybutyl)thiophene) from a weakly conductive conjugated polymer into a high-carrier-concentration p-type semiconductor, providing ample transport carriers for hole transport and improving carrier mobility. Furthermore, doping with 1,3,5-tribromobenzene lowers the valence band top energy level of poly(3-(4-carboxybutyl)thiophene) due to the strong electron-withdrawing effect, tuning it to better match the valence band top energy level of perovskite. This energy level matching reduces the hole extraction barrier, allowing photogenerated holes to flow more smoothly from the perovskite layer through the hole extraction layer to the hole transport layer, reducing non-radiative recombination. Furthermore, the carboxyl groups in the side chains of poly(3-(4-carboxybutyl)thiophene) possess strong polarity, enabling them to form stable coordination bonds with lead ions on the perovskite layer surface. This anchors the hole extraction layer and the perovskite layer, improving interfacial stability. On the other hand, it also passivates defects on the perovskite surface, further reducing interfacial recombination and providing a stable lower interface for the perovskite layer, thus enhancing device stability. In other words, in the photovoltaic cell of this application, the hole extraction layer enables a better energy level match between the perovskite layer and the hole transport layer, thereby increasing carrier transport rate, reducing non-radiative recombination, and improving the conversion efficiency of the photovoltaic cell. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a photovoltaic cell provided in one embodiment of this application.

[0028] Explanation of reference numerals in the attached figures:

[0029] 10-Bottom electrode; 20-Substrate structure; 21-Silicon bottom cell structure; 22-First transparent conductive layer; 30-Hole transport layer; 40-Hole extraction layer; 50-Perovskite layer; 60-Electron transport layer; 70-Second transparent conductive layer; 80-Top electrode. Detailed Implementation

[0030] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0034] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0035] One embodiment of this application provides a photovoltaic cell, including a substrate structure 20, a hole transport layer 30, a hole extraction layer 40, and a perovskite layer 50 stacked sequentially; the hole transport layer 30 is made of nickel oxide; the hole extraction layer 40 is made of 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene).

[0036] The aforementioned photovoltaic cell includes a hole extraction layer 40 disposed between a hole transport layer 30 and a perovskite layer 50. The hole transport layer 30 is made of nickel oxide, and the hole extraction layer 40 is made of 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene). Poly(3-(4-carboxybutyl)thiophene) is a polymer with a conjugated structure containing carboxybutyl side chains, enabling the 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) to have good anchoring ability on the nickel oxide surface. The valence band top energy level of the perovskite material is typically between -5.4 eV and -5.6 eV, with an offset of over 0.6 eV between it and the nickel oxide hole transport layer 30. Undoped poly(3-(4-carboxybutyl)thiophene) has a higher valence band top energy level, resulting in poorer energy level matching with the perovskite material and a higher hole extraction barrier. Poly(3-(4-carboxybutyl)thiophene), as a conjugated polymer, has thiophene units that exhibit electron-donating properties. The bromine atoms in the 1,3,5-tribromobenzene molecule are strong electron-withdrawing groups, which can extract electrons from the thiophene backbone of poly(3-(4-carboxybutyl)thiophene) through charge transfer. This transforms poly(3-(4-carboxybutyl)thiophene) from a weakly conductive conjugated polymer into a high-carrier-concentration p-type semiconductor, providing ample transport carriers for hole transport and improving carrier mobility. Furthermore, doping with 1,3,5-tribromobenzene lowers the valence band top energy level of poly(3-(4-carboxybutyl)thiophene) due to the strong electron-withdrawing effect, tuning it to a level more closely matched with the valence band top energy level of perovskite. This energy level matching reduces the hole extraction barrier, allowing photogenerated holes to flow more smoothly from the perovskite layer 50 through the hole extraction layer 40 to the hole transport layer 30, reducing non-radiative recombination. Furthermore, the carboxyl groups in the side chains of poly(3-(4-carboxybutyl)thiophene) are highly polar and can form stable coordination bonds with lead ions on the surface of the perovskite layer 50, thereby anchoring the hole extraction layer 40 and the perovskite layer 50 and improving interface stability. On the other hand, it can also passivate defects on the perovskite surface, further reducing interfacial recombination and providing a stable lower interface for the perovskite layer 50, thus improving device stability. In other words, in the photovoltaic cell of this application, the hole extraction layer 40 enables a better match between the energy levels of the perovskite layer 50 and the hole transport layer 30, thereby increasing the carrier transport rate, reducing non-radiative recombination, and improving the conversion efficiency of the photovoltaic cell.

[0037] In some embodiments, the mass ratio of poly(3-(4-carboxybutyl)thiophene) to 1,3,5-tribromobenzene in the 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) is (8~20):1.

[0038] Within the aforementioned mass ratio range of poly(3-(4-carboxybutyl)thiophene) and 1,3,5-tribromobenzene, p-type doping of poly(3-(4-carboxybutyl)thiophene) with 1,3,5-tribromobenzene results in better energy level matching between the hole extraction layer 40 and the perovskite layer 50. Simultaneously, it also maintains the good anchoring and passivation effects of the hole extraction layer 40 on the perovskite layer 50, thereby improving carrier transport rate, reducing non-radiative recombination, and increasing the conversion efficiency of the photovoltaic cell. Optionally, in 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene), the mass ratio of poly(3-(4-carboxybutyl)thiophene) to 1,3,5-tribromobenzene is 8:1, 10:1, 12:1, 14:1, 16:1, 18:1, or 20:1. Alternatively, in 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene), the mass ratio of poly(3-(4-carboxybutyl)thiophene) to 1,3,5-tribromobenzene can also be within the range between any two of the above mass ratios.

[0039] In some embodiments, the hole transport layer 30 is made of nickel oxide.

[0040] In some embodiments, the hole extraction layer 40 is made of 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene).

[0041] In some embodiments, the material of the hole extraction layer 40 further includes nanoparticles; the nanoparticles include at least one of alumina nanoparticles, magnesium oxide nanoparticles, and silicon oxide nanoparticles.

[0042] Furthermore, the hole extraction layer 40 may also include nanoparticles, which helps the hole extraction layer 40 to be better anchored on the nickel oxide hole transport layer 30, improving the stability of the device. At the same time, the nanoparticles also help passivate defects in the perovskite layer 50, reduce open-circuit voltage loss, and thus improve the stability and overall performance of the photovoltaic cell.

[0043] In some embodiments, the hole extraction layer 40 is made of 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) and nanoparticles.

[0044] In some embodiments, the mass ratio of 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) to nanoparticles is (50~1000):1.

[0045] When the mass of the nanoparticles is too small, their effect on improving anchoring and passivation is not significant. When the mass of the nanoparticles is too large, it may affect the energy level matching effect between the hole extraction layer 40 and the perovskite layer 50. Optionally, the mass ratio of 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) to nanoparticles can be 50:1, 100:1, 150:1, 200:1, 300:1, 400:1, 500:1, 600:1, 700:1, 800:1, 900:1, or 1000:1, or the mass ratio of 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) to nanoparticles can also be within the range between any two of the above mass ratios.

[0046] In some embodiments, the substrate structure 20 includes a silicon bottom battery structure 21 and a first transparent conductive layer 22 stacked together; the first transparent conductive layer 22 is disposed between the silicon bottom battery structure 21 and the hole transport layer 30.

[0047] In some embodiments, the surface where the silicon bottom battery structure 21 and the first transparent conductive layer 22 contact is textured.

[0048] Furthermore, traditional SAM materials typically suffer from thickness sensitivity and low coverage. For example, traditional carbazole-based SAM materials (such as 2pacz, meo-2pacz, me-4pacz, etc.) struggle to cover the base of the pyramid on textured surfaces, resulting in insufficient coverage. This hinders the achievement of good crystallization on the perovskite surface, impacting conversion efficiency. Similarly, Spiro-OMeTAD and other SAM materials are thickness-sensitive, requiring ultrathin films for efficient hole transport. Even slight increases in thickness cause a sharp drop in hole transport efficiency, making them unsuitable for application on textured surfaces. In perovskite-silicon tandem photovoltaic cells, the interface between the perovskite top cell and the crystalline silicon bottom cell is usually textured. 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) has the characteristic of being thickness-insensitive, resulting in good uniformity of the prepared film and maintaining efficient hole transport over a wide thickness range. This makes the hole extraction layer 40 of this application more suitable for perovskite-silicon tandem photovoltaic cells, enabling the perovskite layer 50 to have good spreadability and crystallization on its surface, thereby achieving higher conversion efficiency of the tandem cell.

[0049] In some embodiments, the thickness of the hole extraction layer 40 is 2nm to 50nm.

[0050] Optionally, the thickness of the hole extraction layer 40 is 2nm, 5nm, 8nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm or 50nm, or the thickness of the hole extraction layer 40 may be within any two of the above thicknesses.

[0051] In some embodiments, the hole transport layer 30 has a thickness of 1 nm to 15 nm.

[0052] Optionally, the thickness of the hole transport layer 30 is 1nm, 2nm, 3nm, 5nm, 6nm, 8nm, 10nm, 12nm or 15nm, or the thickness of the hole transport layer 30 can be within any two of the above thicknesses.

[0053] Refer again Figure 1 As shown, in some embodiments, the photovoltaic cell includes a bottom electrode 10, a silicon bottom cell structure 21, a first transparent conductive layer 22, a hole transport layer 30, a hole extraction layer 40, a perovskite layer 50, an electron transport layer 60, a second transparent conductive layer 70, and a top electrode 80, which are stacked sequentially.

[0054] In some embodiments, the perovskite layer 50 comprises a material having the following general chemical formula: ABX3, wherein A includes FA. + MA + Cs + and Rb + At least one of them, B includes Pb 2+ Sn 2+ and Sr 2+ At least one of them, X includes Cl - ,Br - and I - At least one of them.

[0055] In some embodiments, the material of the first transparent conductive layer 22 includes at least one of ITO, IZO, IWO, ICO, and AZO.

[0056] In some embodiments, the material of the second transparent conductive layer 70 includes at least one of ITO, IZO, IWO, ICO, and AZO.

[0057] In some embodiments, the material of the electron transport layer 60 includes at least one of SnO2, TiO2, ZnO, In2O3, and fullerenes and their derivatives.

[0058] Another embodiment of this application provides a method for preparing a photovoltaic cell, comprising the following steps:

[0059] Provide a base structure 20;

[0060] A hole transport layer 30 is prepared on the surface of the substrate structure 20, and the material of the hole transport layer 30 includes nickel oxide;

[0061] A hole extraction layer 40 is prepared on the surface of the hole transport layer 30 away from the substrate structure 20. The material of the hole extraction layer 40 includes 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene).

[0062] A perovskite layer 50 is prepared on the surface of the hole extraction layer 40 that is far from the hole transport layer 30.

[0063] In some embodiments, the method for preparing the hole extraction layer 40 includes the following steps:

[0064] A solution of poly(3-(4-carboxybutyl)thiophene) doped with 1,3,5-tribromobenzene is applied to the surface of the hole transport layer 30 away from the substrate structure 20 to form a liquid film.

[0065] The liquid film is annealed.

[0066] In some embodiments, the annealing temperature is 100°C to 140°C.

[0067] Optionally, the annealing temperature is 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃ or 140℃, or the annealing temperature may be within any two of the above temperatures.

[0068] In some embodiments, the annealing process takes 10 to 30 minutes.

[0069] Optionally, the annealing time can be 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min or 30 min, or the annealing time can be within any two of the above times.

[0070] Another embodiment of this application provides a photovoltaic module, including:

[0071] Cover plate;

[0072] At least one battery string, the battery string comprising a photovoltaic cell of any one of the above, or a photovoltaic cell prepared by any one of the above methods;

[0073] And the encapsulation layer, which is located between the cover plate and the battery string, with the cover plate connected to the battery string through the encapsulation layer.

[0074] The following is the specific implementation:

[0075] Example 1

[0076] Photovoltaic cell fabrication:

[0077] (1) Weigh 5 mg of poly(3-(4-carboxybutyl)thiophene) and dissolve it in 1 ml of methanol to obtain a methanol solution. Then add 2 mg of 1,3,5-tribromobenzene to the methanol solution and stir overnight to prepare a 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) solution.

[0078] (2) Provide a silicon-based solar cell, wherein an IZO first transparent conductive layer 22 and a nickel oxide hole transport layer 30 are sequentially deposited on the surface of the silicon-based solar cell;

[0079] (3) Take an appropriate amount of 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) solution and uniformly drop it onto the nickel oxide hole transport layer 30. Spin coat at 5000 rpm for 20 s, then anneal at 140 °C for 10 min, and then cool to room temperature to prepare the hole extraction layer 40.

[0080] (4) Take 50 μl of perovskite precursor solution and spread it on the surface of cavity extraction layer 40. Spin coat at 5000 rpm for 30 s, and then anneal at 100 °C for 10 min to prepare perovskite layer 50. The perovskite precursor solution is prepared by mixing CsI, PbI2, PbBr2, FAI and MAI in DMF and DMSO in a certain molar ratio.

[0081] (5) Deposit C on perovskite using a vapor deposition machine 60 Thin film; using ALD equipment in C 60 SnO2 was deposited on the thin film to prepare an electron transport layer 60.

[0082] (6) An IZO film was deposited on the electron transport layer 60 by magnetron sputtering to prepare a second transparent conductive layer 70.

[0083] (7) An Ag electrode is deposited on the second transparent conductive layer 70.

[0084] Comparative Example 1

[0085] Photovoltaic cell fabrication:

[0086] (1) Weigh 1 mg of 2pacz hole transport material, dissolve it completely in 1 mL of IPA solution, stir overnight to prepare 2pacz solution.

[0087] (2) Provide a silicon-based solar cell, wherein an IZO first transparent conductive layer 22 and a nickel oxide hole transport layer 30 are sequentially deposited on the surface of the silicon-based solar cell;

[0088] (3) Take an appropriate amount of 2pacz solution and add it evenly to the nickel oxide hole transport layer 30. Spin coat at 5000rpm for 20s, then anneal at 140℃ for 10min, and then cool to room temperature to prepare the hole extraction layer 40.

[0089] (4) Take 50 μl of perovskite precursor solution and spread it on the surface of cavity extraction layer 40. Spin coat at 5000 rpm for 30 s, and then anneal at 100 °C for 10 min to prepare perovskite layer 50. The perovskite precursor solution is prepared by mixing CsI, PbI2, PbBr2, FAI and MAI in DMF and DMSO in a certain molar ratio.

[0090] (5) Deposit C on perovskite using a vapor deposition machine 60 Thin film; using ALD equipment in C 60 SnO2 was deposited on the thin film to prepare an electron transport layer 60.

[0091] (6) An IZO film was deposited on the electron transport layer 60 by magnetron sputtering to prepare a second transparent conductive layer 70.

[0092] (7) An Ag electrode is deposited on the second transparent conductive layer 70.

[0093] Adjust the power of the solar simulator to 100mw / cm² 2 To simulate the AM 1.5G radiation standard, the current and voltage values ​​of the device were read by a computer connected to a Keithley 2450 power meter. Before measuring the current density-voltage curves, the light intensity was calibrated using a Newport standard silicon cell 91150, with the device in forward and reverse scan mode at a scan rate of 0.05 V / s. The photovoltaic cells prepared in Example 1 and Comparative Example 1 were tested, and the test results are shown in the table below:

[0094]

[0095] The test results show that, in Example 1 of this application, the preparation of a 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutylthiophene) hole extraction layer 40 between the nickel oxide hole transport layer 30 and the perovskite layer 50 can make the energy levels between the perovskite layer 50 and the hole transport layer 30 more matched, thereby improving the carrier transport rate, reducing non-radiative recombination, and improving the conversion efficiency of the photovoltaic cell.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A photovoltaic cell, characterized in that, The device comprises a substrate structure, a hole transport layer, a hole extraction layer, and a perovskite layer stacked sequentially. The hole transport layer is made of nickel oxide. The hole extraction layer is made of 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene), wherein the mass ratio of poly(3-(4-carboxybutyl)thiophene) to 1,3,5-tribromobenzene is (8~20):

1. The hole extraction layer further comprises nanoparticles. The nanoparticles include at least one of alumina nanoparticles, magnesium oxide nanoparticles, and silicon oxide nanoparticles. The mass ratio of 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) to the nanoparticles is (50~1000):

1.

2. The photovoltaic cell according to claim 1, characterized in that, The substrate structure includes a silicon substrate battery structure and a first transparent conductive layer stacked together; the first transparent conductive layer is disposed between the silicon substrate battery structure and the hole transport layer.

3. The photovoltaic cell according to claim 2, characterized in that, The surface where the silicon-based battery structure contacts the first transparent conductive layer is textured.

4. The photovoltaic cell according to any one of claims 1 to 3, characterized in that, The thickness of the hole extraction layer is 2nm~50nm; and / or, The thickness of the hole transport layer is 1 nm to 15 nm.

5. A method for preparing a photovoltaic cell, characterized in that, Includes the following steps: Provide the base structure; A hole transport layer is prepared on the surface of the substrate structure, wherein the material of the hole transport layer includes nickel oxide; A hole extraction layer is prepared on the surface of the hole transport layer away from the substrate structure. The material of the hole extraction layer includes 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene), wherein the mass ratio of poly(3-(4-carboxybutyl)thiophene) to 1,3,5-tribromobenzene is (8~20):

1. The material of the hole extraction layer also includes nanoparticles; the nanoparticles include at least one of alumina nanoparticles, magnesium oxide nanoparticles, and silicon oxide nanoparticles; the mass ratio of 1,3,5-tribromobenzene-doped poly(3-(4-carboxybutyl)thiophene) to the nanoparticles is (50~1000):

1. A perovskite layer is prepared on the surface of the hole extraction layer that is away from the hole transport layer.

6. The method for preparing a photovoltaic cell according to claim 5, characterized in that, The method for preparing the hole extraction layer includes the following steps: A solution of poly(3-(4-carboxybutylthiophene) doped with 1,3,5-tribromobenzene is applied to the surface of the hole transport layer away from the substrate structure to form a liquid film; The liquid film is then annealed.

7. A photovoltaic module, characterized in that, include: Cover plate; At least one battery string, the battery string comprising a photovoltaic cell according to any one of claims 1 to 4, or a photovoltaic cell prepared by the method of preparing a photovoltaic cell according to claim 5 or 6; And an encapsulation layer, which is located between the cover plate and the battery string, and the cover plate is connected to the battery string through the encapsulation layer.

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