Solar cell, preparation method thereof and photovoltaic module

Abstract

The invention provides a solar cell and a preparation method thereof, and a photovoltaic module, the solar cell comprises a substrate, and a first transmission layer, a perovskite layer, a second transmission layer and a silver-carbon composite electrode which are sequentially arranged on the substrate, the silver-carbon composite electrode is located on the surface of the second transmission layer, and the silver-carbon composite electrode comprises a first electrode layer and a second electrode layer, the first electrode layer comprises a conductive polymer and a carbon material, the second electrode layer comprises silver, and the thickness of the second electrode layer is 10-20 nm. The solar cell provided by the invention has higher photoelectric conversion performance and lower manufacturing cost.

Description

Technical Field

[0001] This application relates to the field of solar cells, and more particularly to a solar cell and its preparation method, and a photovoltaic module. Background Technology

[0002] Perovskite solar cells are devices that convert solar energy into electrical energy, and they have attracted widespread attention due to their excellent photoelectric properties.

[0003] In related technologies, silver is commonly used to prepare electrodes for perovskite solar cells. However, silver electrodes are susceptible to corrosion from ion migration in perovskite solar cells, leading to poor electrode stability and consequently, a decrease in the efficiency of the perovskite solar cells. Furthermore, silver is a precious metal, which is detrimental to reducing the manufacturing cost of perovskite solar cells. Summary of the Invention

[0004] To address the aforementioned technical issues, this application discloses a solar cell and its fabrication method, as well as a photovoltaic module, which reduces manufacturing costs while minimizing the performance degradation of perovskite solar cells.

[0005] In a first aspect, this application provides a solar cell, including a substrate and a first transport layer, a perovskite layer, a second transport layer and a silver-carbon composite electrode sequentially disposed on the substrate. The silver-carbon composite electrode is located on the surface of the second transport layer. The silver-carbon composite electrode includes a first electrode layer and a second electrode layer. The first electrode layer includes a conductive polymer and a carbon material, and the second electrode layer includes silver. The thickness of the second electrode layer is 10 nm to 20 nm.

[0006] In some embodiments of this application, the thickness of the first electrode layer is 2μm to 5μm, and the width of the silver-carbon composite electrode is 0.04mm to 0.2mm.

[0007] In some embodiments of this application, the conductive polymer has a mass percentage content of 5% to 15% in the first electrode layer, and the carbon material has a mass percentage content of 85% to 95% in the first electrode layer.

[0008] In some embodiments of this application, the first transport layer is an electron transport layer and the second transport layer is a hole transport layer;

[0009] Alternatively, the first transport layer may be a hole transport layer, and the second transport layer may be an electron transport layer.

[0010] In some embodiments of this application, the conductive polymer includes at least one of polyaniline and polythiophene.

[0011] In some embodiments of this application, the carbon material includes a first carbon material and a second carbon material, wherein the first carbon material is carbon black and the second carbon material is selected from at least one of graphite and graphene.

[0012] In some embodiments of this application, the substrate includes a bottom battery and a carrier recombination layer stacked on the bottom battery, wherein the first transport layer is disposed on the carrier recombination layer;

[0013] Alternatively, the substrate may be a transparent conductive substrate, and the first transport layer may be disposed on the transparent conductive substrate; the first transport layer may be a hole transport layer or an electron transport layer.

[0014] Secondly, this application provides a method for fabricating a solar cell as described in the first aspect, comprising the following steps:

[0015] Provide a base;

[0016] A first transport layer, a perovskite layer, a second transport layer, and a silver-carbon composite electrode are sequentially fabricated on the surface of the substrate.

[0017] The preparation process of the silver-carbon composite electrode includes:

[0018] The first electrode layer is prepared on the surface of the second transport layer;

[0019] A second electrode layer is prepared on the surface of the first electrode layer to form the silver-carbon composite electrode.

[0020] In some embodiments of this application, the fabrication steps of the first electrode layer include:

[0021] A first electrode slurry containing conductive polymer and carbon material is coated on the surface of the second transport layer, and the first electrode layer is obtained after drying and a first annealing treatment.

[0022] The fabrication steps of the second electrode layer include:

[0023] Silver is vapor-deposited onto the surface of the first electrode layer, and after a second annealing treatment, the second electrode layer is formed. The temperature of the first annealing treatment is 140℃~160℃, and the temperature of the second annealing treatment is 130℃~160℃.

[0024] In some embodiments of this application, the mass ratio of proton-acidified polyaniline to the first carbon material in the first electrode slurry is 1:10 to 15.

[0025] In some embodiments of this application, the conductive polymer is polyaniline, and the preparation process of the first electrode paste includes:

[0026] Polyaniline, ammonium salt and protic acid are mixed and reacted to obtain protic acid-acidified polyaniline;

[0027] The proton-acidified polyaniline, carbon material, dispersant, and binder are mixed and dissolved in a solvent to obtain the first electrode slurry.

[0028] In some embodiments of this application, the molar concentration of the protic acid is 0.1 mol / L to 0.5 mol / L.

[0029] In some embodiments of this application, the protic acid is selected from at least one of hydrochloric acid, sulfuric acid, and phosphoric acid, and the ammonium salt is selected from at least one of ammonium sulfate and ammonium chloride.

[0030] In some embodiments of this application, the dispersant is selected from at least one of polyvinylpyrrolidone, polyvinyl alcohol, hexadecanetrimethylammonium bromide, and sodium dodecylbenzenesulfonate; the binder is selected from at least one of hydroxymethyl cellulose, polyacrylic acid, and polyvinyl alcohol; and the solvent is selected from at least one of isopropanol, diethyl ether, ethanol, and chloroform.

[0031] Thirdly, this application provides a photovoltaic module, which includes a solar cell as described in the first aspect, or the photovoltaic module includes a solar cell prepared by the preparation method described in the second aspect.

[0032] Compared with the prior art, this application has at least the following beneficial effects:

[0033] This application provides a solar cell, its fabrication method, and a photovoltaic module. The solar cell includes a substrate and a first transport layer, a perovskite layer, a second transport layer, and a silver-carbon composite electrode sequentially disposed on the substrate. The silver-carbon composite electrode is located on the surface of the second transport layer and includes a first electrode layer and a second electrode layer. The first electrode layer includes a conductive polymer and carbon material, and the second electrode layer includes silver. The thickness of the second electrode layer is 10 nm to 20 nm. Compared to existing perovskite solar cell electrode structures, the silver-carbon composite electrode of this application includes a first electrode layer and a second electrode layer. The first electrode layer includes a conductive polymer and carbon material, giving it stronger conductivity than existing carbon electrodes. It also avoids the problem of battery performance degradation caused by halogen atoms in the perovskite layer diffusing to the silver electrode and corroding it, as is common in related technologies. The second electrode layer is a 10 nm to 20 nm silver electrode layer, significantly thinner than existing silver electrodes, thus greatly reducing the amount of silver used and lowering the manufacturing cost of the solar cell. With the combined effect of the first electrode layer and the second electrode layer, the silver-carbon composite electrode of this application has excellent conductivity and lower manufacturing cost, which makes the solar cell of this application have higher photoelectric conversion performance, anti-attenuation performance and lower manufacturing cost. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments 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.

[0035] Figure 1 This is a schematic diagram of the structure of a perovskite solar cell in one embodiment of this application;

[0036] Figure 2 This is a schematic diagram of the structure of a perovskite solar cell in another embodiment of this application;

[0037] Figure 3 This is a schematic diagram of the structure of a perovskite solar cell in another embodiment of this application;

[0038] Figure 4 This is a schematic diagram of the structure of a perovskite solar cell in the fourth embodiment of this application.

[0039] Explanation of reference numerals in the attached figures: 1-substrate, 2-first transport layer, 3-perovskite layer, 4-second transport layer, 5-silver-carbon composite electrode, 6-bottom cell, 7-carrier composite layer, 51-first electrode layer, 52-second electrode layer. Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0042] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0043] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; 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, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0044] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0045] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.

[0046] Perovskite solar cells commonly use silver as an electrode. However, silver electrodes are corroded by ion migration within the perovskite layer, resulting in significant color changes and severe efficiency degradation, leading to poor electrode stability. For conventional perovskite solar cells, the poor stability of the silver electrode is primarily due to the diffusion and migration of silver particles from the silver electrode into the hole transport layer, causing corrosion. Furthermore, the resistance of the silver electrode increases with the degree of corrosion, leading to a sharp decline in cell performance. Additionally, iodide and methylamine ions in the perovskite layer diffuse through the hole transport layer to the silver electrode surface and accumulate, leading to the formation of silver iodide at the electrode interface, which also corrodes the silver electrode. This accumulation process provides a driving force for further iodide ion diffusion, further exacerbating the decomposition of the perovskite layer. The inventors also found that although carbon electrodes have better corrosion resistance and a more suitable work function, which can improve the electrode stability problem caused by silver electrode corrosion, the photoelectric conversion efficiency of perovskite solar cells based on carbon electrodes is relatively low.

[0047] In view of this, firstly, this application provides a solar cell. For example... Figure 1As shown, the solar cell includes a substrate 1 and a first transport layer 2, a perovskite layer 3, a second transport layer 4, and a silver-carbon composite electrode 5 sequentially disposed on the substrate. The silver-carbon composite electrode is located on the surface of the second transport layer. The silver-carbon composite electrode includes a first electrode layer 51 and a second electrode layer 52. The first electrode layer includes a conductive polymer and a carbon material, and the second electrode layer includes silver. The thickness of the second electrode layer is 10 nm to 20 nm.

[0048] The silver-carbon composite electrode of this application includes a first electrode layer and a second electrode layer. The first electrode layer comprises a conductive polymer and carbon material, giving it enhanced conductivity. The second electrode layer is a silver electrode layer with a thickness of 10 nm to 20 nm. When the thickness of the second electrode layer is too small (e.g., less than 10 nm), the silver electrode layer is too thin, increasing the contact resistance between the first and second electrode layers. When the thickness of the second electrode layer is too large (e.g., greater than 20 nm), the improvement in conductivity of the silver-carbon composite electrode is no longer significant, and it increases the amount of silver used, thus increasing costs. By controlling the thickness of the second electrode layer within the above-mentioned range, the amount of silver used is significantly reduced while maintaining high conductivity in the silver-carbon composite electrode. Through the combined effect of the first and second electrode layers, the silver-carbon composite electrode of this application exhibits excellent conductivity while reducing manufacturing costs, resulting in solar cells with higher photoelectric conversion performance, better degradation resistance, and lower manufacturing costs.

[0049] In one optional embodiment, the thickness of the first electrode layer is 2 μm to 5 μm, and the width of the silver-carbon composite electrode is 0.04 mm to 0.2 mm. When the thickness of the first electrode layer is too small (e.g., less than 2 μm), it is difficult to effectively prevent halogen atoms in the perovskite layer from diffusing to the second electrode layer, leading to corrosion of the silver electrode. When the thickness of the first electrode layer is too large (e.g., greater than 5 μm), the distance of the photogenerated current from the first transport layer to the second transport layer increases, and the power attenuation of the device increases accordingly. When the width of the silver-carbon composite electrode is too small (e.g., less than 0.04 mm), the contact reliability between the silver-carbon composite electrode and the second transport layer decreases. When the width of the silver-carbon composite electrode is too large (e.g., greater than 0.2 mm), it increases the shading of the solar cell, which is detrimental to improving the photoelectric conversion efficiency of the solar cell. This application, by controlling the thickness of the first electrode layer and the width of the silver-carbon composite electrode within the above-mentioned ranges, reduces the overall thickness of the silver-carbon composite electrode while facilitating the obtaining of a silver-carbon composite electrode with high conductivity.

[0050] In one optional embodiment, the conductive polymer has a mass percentage content of 5% to 15% in the first electrode layer, and the carbon material has a mass percentage content of 85% to 95% in the first electrode layer. By controlling the content of the conductive polymer and the carbon material within the above ranges, it is beneficial to obtain a first electrode layer with high conductivity, and thus obtain a silver-carbon composite electrode with high conductivity.

[0051] In one alternative implementation, such as Figure 2 As shown, the first transport layer 2 is an electron transport layer, and the second transport layer 4 is a hole transport layer. This structure is a formal perovskite solar cell structure; or, as... Figure 3 As shown, the first transport layer 2 is a hole transport layer, and the second transport layer 4 is an electron transport layer. This structure is an inverted perovskite solar cell structure. The silver-carbon composite electrode of this application can be applied to both conventional perovskite solar cell structures and inverted perovskite solar cell structures, thus broadening the application scenarios of perovskite solar cells.

[0052] In one alternative embodiment, the conductive polymer includes at least one of polyaniline and polythiophene, preferably polyaniline. Applying the aforementioned conductive polymer to the first electrode layer of the silver-carbon composite electrode is advantageous for obtaining a first electrode layer with high conductivity.

[0053] In one optional embodiment, the carbon material includes a first carbon material and a second carbon material, wherein the first carbon material is carbon black and the second carbon material is selected from graphite and graphene. The mass ratio between the first carbon material and the second carbon material in this application can be 1:0.1 to 0.5. Applying the aforementioned carbon material to the first electrode layer of the silver-carbon composite electrode can improve the conductivity of the carbon material while reducing its cost.

[0054] In one alternative implementation, such as Figure 4 As shown, the substrate 1 includes a bottom cell 6 and a carrier recombination layer 7, with a first transport layer 2 disposed on the carrier recombination layer 7; alternatively, the substrate can be a transparent conductive substrate, with the first transport layer disposed on the transparent conductive substrate. The first transport layer can be a hole transport layer or an electron transport layer. The substrate of this application can be either of the above two types, that is, it can be a tandem perovskite solar cell based on a crystalline silicon bottom cell, or it can be a single-junction perovskite solar cell; this application does not limit this.

[0055] Secondly, this application provides a method for fabricating a solar cell as described in the first aspect, comprising the following steps:

[0056] Provide a base;

[0057] A first transport layer, a perovskite layer, a second transport layer, and a silver-carbon composite electrode are sequentially fabricated on the surface of a substrate.

[0058] The preparation process of the silver-carbon composite electrode includes:

[0059] A first electrode layer is fabricated on the surface of the second transport layer;

[0060] A second electrode layer is prepared on the surface of the first electrode layer to form a silver-carbon composite electrode.

[0061] The substrate used in this application can be a transparent conductive substrate, such as indium tin oxide (ITO) conductive glass. This application does not impose any particular limitation on the substrate thickness; the thickness can be adjusted according to actual needs. For example, the substrate thickness can be 0.08 mm to 3 mm.

[0062] This application does not impose any particular limitations on the preparation methods of the first transport layer, the perovskite layer, and the second transport layer. For example, in the preparation of a formal perovskite solar cell, tin dioxide (SnO2) can be spin-coated onto the substrate surface to form an electron transport layer, i.e., the first transport layer, with a thickness of 10–20 nm; perovskite material can be spin-coated onto the surface of the first transport layer to form a perovskite layer with a thickness of 300 nm–500 nm; and hole transport layer material can be spin-coated onto the surface of the perovskite layer to form a hole transport layer with a thickness of 10 nm–20 nm.

[0063] The solar cell fabrication method provided in this application involves preparing a silver-carbon composite electrode on the surface of the second transport layer. This silver-carbon composite electrode exhibits excellent conductivity while avoiding the performance degradation problem caused by halogen atoms in the perovskite layer directly diffusing to the silver electrode and corroding it, as is common in related technologies. Furthermore, the fabrication method of this application has the advantages of readily available silver-carbon composite electrode raw materials and a simple fabrication process, which can significantly reduce the amount of silver used, thereby reducing the manufacturing cost of the solar cell.

[0064] In one optional embodiment, the fabrication step of the first electrode layer includes:

[0065] A first electrode slurry containing conductive polymer and carbon material is coated onto the surface of the second transport layer, and the first electrode layer is obtained after drying and a first annealing treatment.

[0066] The coating method used in this application may include, but is not limited to, blade coating, slot coating, or screen printing. The drying temperature is 60℃~100℃. The purpose of drying is to volatilize the organic components in the first electrode paste, preparing it for the subsequent first annealing treatment. The temperature of the first annealing treatment is 140℃~160℃. The annealing temperature should not be too low or too high. Too low a temperature can easily lead to unreliable contact between the first electrode layer and the transport layer, resulting in increased contact resistance; too high a temperature can easily lead to the attenuation of the activity of the perovskite layer material, affecting the generation of photogenerated carriers. By controlling the temperature of the first annealing treatment within the above range, it is beneficial to obtain a first electrode layer with excellent conductivity.

[0067] In one optional embodiment, the fabrication step of the second electrode layer includes:

[0068] Silver is vapor-deposited onto the surface of the first electrode layer, and after a second annealing treatment, a second electrode layer is formed. The temperature of the second annealing treatment is 130℃~160℃.

[0069] This application utilizes a vapor deposition machine for deposition. Specifically, a photomask with spaced strip-shaped cutouts is placed on the side of the substrate having the first electrode layer. This photomask exposes the first electrode layer through these cutouts while protecting the first transport layer. The substrate is then placed in a vapor deposition machine for deposition, allowing silver to be deposited in the cutouts, i.e., on the surface of the first electrode layer, thus forming the second electrode layer. This application does not impose any particular limitation on the shape of the cutouts in the photomask; for example, they can be strip-shaped cutouts, as long as the cutouts conform to the shape of the first electrode layer. This application also does not impose any particular limitation on the material of the photomask; for example, it can be stainless steel, quartz, etc.

[0070] The second annealing process is carried out at a temperature of 130℃ to 160℃. The annealing temperature should not be too low or too high. Too low a temperature can lead to a decrease in the contact stability between the second and first electrode layers, while too high a temperature can lead to a decrease in the activity of the perovskite layer material, affecting the generation of photogenerated carriers. By controlling the temperature of the second annealing process within the above range, it is beneficial to ensure a tight connection between the second and first electrode layers to form a silver-carbon composite electrode.

[0071] In one optional embodiment, the mass ratio of proton-acidified polyaniline to the first carbon material in the first electrode slurry is 1:10 to 15. By adjusting the mass ratio of proton-acidified polyaniline to the first carbon material within the above range, the first carbon material has a high pore surface area, which can effectively adsorb polyaniline. Polyaniline can improve the conductivity of the material, while the second carbon material can further improve the conductivity, which is beneficial to obtaining a first electrode layer with excellent conductivity.

[0072] In one optional embodiment, the conductive polymer is polyaniline, and the preparation process of the first electrode paste includes:

[0073] Polyaniline, ammonium salt and protic acid are mixed and reacted to obtain protic acid-acidified polyaniline;

[0074] The proton-acidified polyaniline, carbon material, dispersant and binder are mixed and dissolved in a solvent to obtain the first electrode slurry.

[0075] The inventors discovered that polyaniline is a polymer compound with unique electrical and optical properties, exhibiting excellent electrical and electrochemical performance after proton acid acidification. Furthermore, polyaniline possesses high stability, high processability, and adjustable electrical and optical properties. The molecular structure of polyaniline is as follows:

[0076]

[0077] Polyaniline is a class of polymeric compounds with alternating benzene rings and nitrogen atoms in its main chain, giving it a variety of unique properties, such as excellent electrical conductivity, photoelectric properties, electrochromic properties, electrocatalytic properties, and selective permeability. The inventors further discovered that acidifying polyaniline with a protic acid significantly improves its electrical conductivity. Based on the above research, when the first electrode slurry prepared by the method described in this application is used to prepare the first electrode layer, the resulting first electrode layer exhibits excellent electrical conductivity. Here, n is an integer greater than or equal to 2.

[0078] In one alternative embodiment, the molar concentration of the protic acid is 0.1 mol / L to 0.5 mol / L.

[0079] The inventors discovered that the doping mechanism of polyaniline differs from that of other conductive polymers (such as polyacetylene or polypyrrole): doping of other conductive polymers involves the gain or loss of electrons on the main chain, a redox reaction; however, proton acid concentration doping of polyaniline (also known as proton acid acidification) does not change the number of electrons on the polyaniline main chain, but only introduces protons into the polymer chain, making the chain positively charged. Further research revealed that the conductivity of polyaniline depends on the concentration of the dopant. When the molar concentration of the proton acid is 0.1 mol / L to 0.5 mol / L, polyaniline exhibits high conductivity similar to that of a metal, while intrinsic polyaniline has poor conductivity. After proton acid acidification, the conductivity of polyaniline can be increased by more than 12 orders of magnitude. In industrial production, the acid concentration can be easily adjusted to obtain the desired doping concentration of polyaniline, offering advantages such as low cost and convenient process control, making it suitable for industrial-scale preparation of the first electrode layer. Based on the above research, this application regulates the molar concentration of protic acid and pH value within the above range, which is beneficial to obtaining highly conductive polyaniline, thereby obtaining a first electrode layer with high conductivity.

[0080] This application does not impose any particular restrictions on the type of protic acid or ammonium salt, as long as it can acidify polyaniline with protic acid. In one optional embodiment, the protic acid is selected from at least one of hydrochloric acid, sulfuric acid, and phosphoric acid, and the ammonium salt is selected from at least one of ammonium sulfate and ammonium chloride.

[0081] In one optional embodiment, the dispersant is selected from at least one of polyvinylpyrrolidone, polyvinyl alcohol, hexadecanetrimethylammonium bromide and sodium dodecylbenzenesulfonate, which is beneficial to the uniform dispersion of the components in the first electrode slurry; the binder is selected from at least one of hydroxymethyl cellulose, polyacrylic acid and polyvinyl alcohol, which is beneficial to improve the strength of the first electrode layer; and the solvent is selected from at least one of isopropanol, diethyl ether, ethanol and chloroform, which is beneficial to the full dissolution of the components in the first electrode slurry.

[0082] This application does not impose any particular restrictions on the method of adjusting the thickness of the first electrode layer, the thickness of the second electrode layer, and the width of the electrode, as long as the purpose of this application can be achieved. For example, the thickness of the electrode layer can be adjusted by adjusting the pressure of the squeegee in screen printing, and the width of the electrode can be adjusted by adjusting the mesh count, wire diameter, and screen pattern of the screen.

[0083] Thirdly, this application provides a photovoltaic module, which includes a solar cell as described in the first aspect, or the photovoltaic module includes a solar cell prepared by the preparation method described in the second aspect.

[0084] This application also provides a photovoltaic module for converting received light energy into electrical energy and transmitting it to an external load. The photovoltaic module includes: at least one cell string, which is composed of multiple solar cells connected together; an encapsulating film for covering the surface of the cell string; and a cover plate for covering the surface of the encapsulating film facing away from the cell string.

[0085] The following describes a solar cell, its preparation method, and a photovoltaic module according to more specific embodiments of this application.

[0086] Example 1

[0087] <Substrate Pretreatment>

[0088] ITO conductive glass with dimensions of 5cm*5cm and a thickness of 0.2mm (ITO layer thickness of 50nm) was ultrasonically cleaned for 30 minutes each with deionized water, acetone and ethanol. After cleaning, the ITO conductive glass was dried from the side with a clean nitrogen gun.

[0089] <Preparation of Electron Transport Layer>

[0090] Adhesive tape was applied to the ITO layer side of the ITO conductive glass to reserve the back electrode area. The ITO conductive glass was then placed under an ozone cleaner for 30 minutes. 100 mL of deionized water and 10 g of SnO2 (D50 of 50 nm) were mixed and stirred at room temperature for 2 hours to form a uniform and transparent SnO2 aqueous solution with a SnO2 mass fraction of 10 wt%. The untaped side of the ITO conductive glass was placed on the rotating bracket of a spin coater and fixed by vacuum adsorption. The SnO2 aqueous solution was dropped onto the center of the ITO conductive glass using a pipette, and the spin coater was started at a spin coater speed of 3000 rpm for 25 s. After the spin coater stopped rotating, the tape was removed, and the sample was transferred to a heating stage for annealing at 130 °C for 30 minutes to obtain a SnO2 electron transport layer with a thickness of 35 nm. This electron transport layer served as the first transport layer.

[0091] <Preparation of Perovskite Layer>

[0092] 13.3 g of PbI₂ powder was dissolved in 60 mL of a mixed solvent of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (DMF to DMSO volume ratio 9:1), and stirred at 60 °C until completely dissolved to obtain a PbI₂ solution for later use. 1.56 g of methyl iodide (MAI) powder was dissolved in 100 mL of isopropanol solution, and stirred at room temperature until completely dissolved to obtain an MAI solution for later use. A two-step spin-coating method was used. The first step involved spin-coating the PbI₂ solution: 150 μL of the solution was pipetted onto the solution. The first step involved spin-coating a PbI2 solution onto the surface of the electron transport layer at 3000 rpm for 30 seconds. The second step involved spin-coating a MAI solution: 300 μL of MAI solution was added using a pipette and allowed to stand for 30 seconds before spin-coating at 3000 rpm for 30 seconds. After spin-coating, the ITO conductive glass substrate was removed and placed on a hot plate for annealing at 120°C for 10 minutes, resulting in a perovskite layer with a thickness of 500 nm.

[0093] <Preparation of Hole Transport Layer>

[0094] 5g of hole transport layer material spiro-OMeTAD was dissolved in 40mL of chlorobenzene solution to obtain a hole transport layer precursor solution. The hole transport layer precursor solution was dropped onto the surface of the perovskite layer by a pipette and then spin-coated at a speed of 3000rpm for 40s. After spin-coating, annealing was performed at a temperature of 150℃ for 40min to obtain a hole transport layer with a thickness of 20nm, which was used as the second transport layer.

[0095] <Preparation of the positive electrode>

[0096] <Preparation of the first electrode layer>

[0097] 2g of polyaniline and 1g of ammonium sulfate were mixed, and then 100mL of hydrochloric acid with a molar concentration of 0.3mol / L was added. The mixture was stirred at room temperature for 40min to carry out proton acid acidification. After the reaction, the product was washed with distilled water and dried in an oven at 80℃ to obtain proton acid acidified polyaniline.

[0098] 0.5g of proton-acidified polyaniline, 5.4g of carbon black, and 2.5g of graphite were mixed and ground in an agate mill to ensure thorough mixing. Then, 100mL of isopropanol was added as a solvent and the mixture was dispersed evenly using ultrasound. Next, 6g of hydroxypropyl cellulose and 3g of hexadecanetrimethylammonium bromide were added, and the mixture was ground five times with a three-roll mill to obtain a viscous first electrode slurry.

[0099] The first electrode paste was coated onto the surface of the hole transport layer by screen printing. The mesh count of the screen printing was 430 mesh. After drying at 60°C, the first annealing treatment was performed at 150°C for 20 minutes to obtain a first electrode layer with a thickness of 2μm and a width of 0.04mm.

[0100] <Preparation of the second electrode layer>

[0101] A mask is placed on the side of the substrate with the first electrode layer, exposing the first electrode layer through the cutout area of ​​the mask. The hole transport layer is protected by the mask. The substrate is then placed in the vapor deposition chamber for vapor deposition, where silver is deposited on the first electrode layer. The vapor deposition vacuum degree of the vapor deposition machine is 2 × 10⁻⁶. -4 Pa, evaporation rate After the vapor deposition is completed, the mask is removed and a second annealing treatment is performed at a temperature of 150°C for 20 minutes to obtain a second electrode layer with a thickness of 10 nm, thereby forming a silver-carbon composite electrode. The electrode width is shown in Table 1.

[0102] <Preparation of Back Electrode>

[0103] A 50nm thick silver layer was deposited on the ITO-coated side of an ITO conductive glass as the back electrode, resulting in a perovskite solar cell. The cell structure is as follows. Figure 2 As shown.

[0104] Examples 2 to 7

[0105] Except for adjusting the thickness of the first electrode layer, the thickness of the second electrode layer, and the width of the silver-carbon composite electrode according to Table 1 in the <Preparation of the Positive Electrode> section, the rest is the same as in Example 1.

[0106] Example 8

[0107] Except for adjusting the molar concentration of hydrochloric acid to 0.15 mol / L and adjusting the amount of protonated polyaniline added to 0.9 g in the <Preparation of the First Electrode Layer>, the rest is the same as in Example 1.

[0108] Example 9

[0109] Except for adjusting the molar concentration of hydrochloric acid to 0.5 mol / L and adjusting the amount of protonated polyaniline added to 1.25 g in the <Preparation of the First Electrode Layer>, the rest is the same as in Example 1.

[0110] Example 10

[0111] Except for adjusting the annealing temperature of the first annealing treatment to 140°C and the annealing temperature of the second annealing treatment to 140°C in the <Preparation of Positive Electrode> section, the rest is the same as in Example 1.

[0112] Example 11

[0113] Except for adjusting the annealing temperature of the first annealing treatment to 160°C and the annealing temperature of the second annealing treatment to 160°C in the <Preparation of Positive Electrode> section, the rest is the same as in Example 1.

[0114] Example 12

[0115] <Substrate Pretreatment>

[0116] ITO conductive glass with dimensions of 5cm*5cm and a thickness of 0.2mm (ITO layer thickness of 50nm) was ultrasonically cleaned for 30 minutes each with deionized water, acetone and ethanol. After cleaning, the ITO conductive glass was dried from the side with a clean nitrogen gun.

[0117] <Preparation of Hole Transport Layer>

[0118] A back electrode area was pre-reserved by attaching adhesive tape to the side of the ITO conductive glass with the ITO layer. The ITO conductive glass was then placed under an ozone cleaner and cleaned for 30 minutes. 5g of hole transport layer material spiro-OMeTAD was dissolved in 40mL of chlorobenzene solution to obtain a hole transport layer precursor solution. The hole transport layer precursor solution was dropped onto the side of the ITO conductive glass without adhesive tape using a pipette and then spin-coated at 3000rpm for 40s. After spin-coating, the tape was removed and the sample was transferred to a heating stage for annealing at 150℃ for 40 minutes to obtain a hole transport layer with a thickness of 20nm. This hole transport layer was used as the first transport layer.

[0119] <Preparation of Perovskite Layer>

[0120] 13.3 g of PbI₂ powder was dissolved in 60 mL of a mixed solvent of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (DMF to DMSO volume ratio 9:1), and stirred at 60 °C until completely dissolved to obtain a PbI₂ solution for later use. 1.56 g of methyl iodide (MAI) powder was dissolved in 100 mL of isopropanol solution, and stirred at room temperature until completely dissolved to obtain an MAI solution for later use. A two-step spin-coating method was used. The first step involved spin-coating the PbI₂ solution: 150 μL of the solution was pipetted onto the solution. The first step involved spin-coating a PbI2 solution onto the hole transport layer surface at 3000 rpm for 30 seconds. The second step involved spin-coating a MAI solution: 300 μL of MAI solution was added using a pipette and allowed to stand for 30 seconds before spin-coating at 3000 rpm for 30 seconds. After spin-coating, the ITO conductive glass substrate was removed and placed on a hot plate for annealing at 120°C for 10 minutes, resulting in a 500 nm thick perovskite layer.

[0121] <Preparation of Electron Transport Layer>

[0122] 100 mL of deionized water was mixed with 10 g of SnO2 (D50 of 50 nm) and stirred at room temperature for 2 h to form a uniform and transparent SnO2 aqueous solution, wherein the mass fraction of SnO2 in the SnO2 aqueous solution was 10 wt%. The SnO2 aqueous solution was dropped onto the surface of the perovskite layer using a pipette and a spin coater was started. The spin coater was set at a spin coater speed of 3000 rpm for 25 s. After the spin coater stopped rotating, the tape was removed and the sample was transferred to a heating stage for annealing at a temperature of 130 °C for 30 min to obtain a SnO2 electron transport layer with a thickness of 35 nm. This electron transport layer served as the second transport layer.

[0123] <Preparation of the positive electrode>

[0124] <Preparation of the first electrode layer>

[0125] 2g of polyaniline and 1g of ammonium sulfate were mixed, and then 100mL of hydrochloric acid with a molar concentration of 0.3mol / L was added. The mixture was stirred at room temperature for 40min to carry out proton acid acidification. After the reaction, the product was washed with distilled water and dried in an oven at 80℃ to obtain proton acid acidified polyaniline.

[0126] 0.5g of proton-acidified polyaniline, 5.4g of carbon black, and 2.5g of graphite were mixed and ground in an agate mill to ensure thorough mixing. Then, 100mL of isopropanol was added as a solvent and the mixture was dispersed evenly using ultrasound. Next, 6g of hydroxypropyl cellulose and 3g of hexadecanetrimethylammonium bromide were added, and the mixture was ground five times with a three-roll mill to obtain a viscous first electrode slurry.

[0127] The first electrode paste was coated onto the surface of the electron transport layer by screen printing. The mesh size of the screen was 430. After drying at 65°C, the first annealing treatment was performed at 150°C for 20 minutes to obtain a first electrode layer with a thickness of 2μm and a width of 0.04mm.

[0128] <Preparation of the second electrode layer>

[0129] A mask is placed on the side of the substrate with the first electrode layer, exposing the first electrode layer through the cutout area of ​​the mask. The hole transport layer is protected by the mask. The substrate is then placed in the vapor deposition chamber for vapor deposition, where silver is deposited on the first electrode layer. The vapor deposition vacuum degree of the vapor deposition machine is 2 × 10⁻⁶. -4 Pa, evaporation rate After the vapor deposition is completed, the mask is removed and a second annealing treatment is performed at a temperature of 150°C for 20 minutes to obtain a second electrode layer with a thickness of 10 nm, thereby forming a silver-carbon composite electrode.

[0130] <Preparation of Back Electrode>

[0131] A 50nm thick silver layer was deposited on the ITO-coated side of an ITO conductive glass as the back electrode, resulting in a perovskite solar cell. The cell structure is as follows. Figure 3 As shown.

[0132] Comparative Example 1

[0133] Except for the preparation of the positive electrode, which differs from Example 1, the rest is the same as Example 1.

[0134] <Preparation of the positive electrode>

[0135] <Preparation of Conductive Carbon Paste>

[0136] Mix 7g carbon black and 3g graphite, then grind them in an agate mill to ensure thorough mixing. Add 100mL isopropanol as a solvent and disperse evenly using ultrasound. Then add 6g hydroxypropyl cellulose and 3g hexadecanetrimethylammonium bromide, and grind five times with a three-roll mill to obtain a viscous conductive carbon slurry.

[0137] <Preparation of carbon electrode layer>

[0138] Electrode templates were screen printed onto the surface of the electron transport layer. Conductive carbon paste was then evenly applied onto the electrode templates using a scraper. After removing the electrode templates, a regular carbon electrode wet film was obtained. The film was then cured at 120°C for 40 minutes to form a carbon electrode with a thickness of approximately 5 μm. The electrode widths are shown in Table 1.

[0139] Comparative Example 2

[0140] Except for the preparation of the positive electrode, which differs from Example 1, the rest is the same as Example 1.

[0141] <Preparation of the positive electrode>

[0142] A 200 nm thick silver layer was prepared on the surface of the hole transport layer as a positive electrode using an evaporation machine. The electrode width is shown in Table 1.

[0143] Table 1. Preparation parameters of Examples 1-7 and Comparative Examples 1-2

[0144]

[0145]

[0146] Note: In Table 1, " / " indicates that the relevant preparation parameters do not exist.

[0147] Performance testing:

[0148] Photoelectric conversion efficiency test:

[0149] The current (I)-voltage (V) of the solar cells in each embodiment and comparative example were measured using a solar simulator (model: WAVELABS SINUS-300) to obtain the initial photoelectric conversion efficiency (Eta0) and the photoelectric conversion efficiency (Eta1) after 2000 hours of operation.

[0150] Table 2 Performance parameters of each embodiment and comparative example

[0151]

[0152] As can be seen from Examples 1 to 12 and Comparative Examples 1 to 2, compared with existing perovskite solar cells based on carbon electrodes (e.g., Comparative Example 1), the perovskite solar cell with the silver-carbon composite electrode structure of this application has a significantly improved initial photoelectric conversion efficiency. Compared with existing perovskite solar cells based on silver electrodes (e.g., Comparative Example 2), the perovskite solar cell with the silver-carbon composite electrode structure of this application has a significantly improved photoelectric conversion efficiency after 2000 hours of operation, and the Eta1 / Eta0 ratio is higher, indicating that the perovskite solar cell of this application has a lower performance degradation degree, reflecting excellent corrosion resistance. In addition, the thickness of the second electrode layer of this application is significantly reduced compared with the silver electrode thickness of Comparative Example 2, thereby significantly reducing the amount of silver used, thus reducing the manufacturing cost of the perovskite solar cell.

[0153] As can be seen from Examples 1 to 5, by adjusting the thickness of the second electrode layer within the scope of this application, the solar cell exhibits excellent photoelectric conversion efficiency and low performance degradation, thus possessing good photoelectric conversion performance and anti-degradation performance.

[0154] The thickness of the first electrode layer and the width of the composite electrode also typically affect the performance of the solar cell. As can be seen from Examples 1, 6 and 7, by adjusting the above parameters within the scope of this application, it is beneficial to obtain a solar cell with excellent photoelectric conversion performance and corrosion resistance.

[0155] As can be seen from Examples 1, 8 and 9, by controlling the molar concentration of protic acid within the range of this application, it is beneficial to obtain protic acid-acidified polyaniline with excellent conductivity, thereby enabling the prepared perovskite solar cell to exhibit excellent photoelectric conversion performance and corrosion resistance.

[0156] As can be seen from Examples 1, 10 and 11, by controlling the annealing temperature of the first annealing treatment and the annealing temperature of the second annealing treatment within the range of this application, it is beneficial to form a first electrode layer and a second electrode layer with excellent conductivity, that is, to form the silver-carbon composite electrode structure of this application, so that the perovskite solar cell prepared exhibits excellent photoelectric conversion performance and corrosion resistance.

[0157] As can be seen from Example 12, the inverted perovskite solar cell with the silver-carbon composite electrode structure of this application also exhibits excellent photoelectric conversion performance and corrosion resistance.

[0158] The above provides a detailed description of a solar cell and its preparation method, as well as a photovoltaic module, disclosed in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core inventive points of the embodiments of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A solar cell, characterized in that, The system includes a substrate and a first transport layer, a perovskite layer, a second transport layer, and a silver-carbon composite electrode sequentially disposed on the substrate. The silver-carbon composite electrode is located on the surface of the second transport layer. The silver-carbon composite electrode includes a first electrode layer and a second electrode layer. The first electrode layer includes a conductive polymer and a carbon material, and the second electrode layer includes silver. The thickness of the second electrode layer is 10 nm to 20 nm.

2. The solar cell according to claim 1, characterized in that, The thickness of the first electrode layer is 2μm to 5μm, and the width of the silver-carbon composite electrode is 0.04mm to 0.2mm.

3. The solar cell according to claim 1, characterized in that, The conductive polymer has a mass percentage content of 5% to 15% in the first electrode layer, and the carbon material has a mass percentage content of 85% to 95% in the first electrode layer.

4. The solar cell according to claim 1, characterized in that, The first transport layer is an electron transport layer, and the second transport layer is a hole transport layer; Alternatively, the first transport layer may be a hole transport layer, and the second transport layer may be an electron transport layer.

5. The solar cell according to claim 1, characterized in that, The conductive polymer includes at least one of polyaniline and polythiophene.

6. The solar cell according to claim 1, characterized in that, The carbon material includes a first carbon material and a second carbon material, wherein the first carbon material is carbon black and the second carbon material is selected from at least one of graphite and graphene.

7. The solar cell according to claim 4, characterized in that, The substrate includes a bottom cell and a carrier recombination layer stacked on the bottom cell, wherein the first transport layer is disposed on the carrier recombination layer; Alternatively, the substrate may be a transparent conductive substrate, and the first transport layer may be disposed on the transparent conductive substrate; the first transport layer may be a hole transport layer or an electron transport layer.

8. A method for preparing a solar cell according to any one of claims 1 to 7, characterized in that, Includes the following steps: Provide a base; A first transport layer, a perovskite layer, a second transport layer, and a silver-carbon composite electrode are sequentially fabricated on the surface of the substrate. The preparation process of the silver-carbon composite electrode includes: The first electrode layer is prepared on the surface of the second transport layer; A second electrode layer is prepared on the surface of the first electrode layer to form the silver-carbon composite electrode.

9. The preparation method according to claim 8, characterized in that, The fabrication steps of the first electrode layer include: A first electrode slurry containing conductive polymer and carbon material is coated on the surface of the second transport layer, and the first electrode layer is obtained after drying and a first annealing treatment. The fabrication steps of the second electrode layer include: Silver is vapor-deposited onto the surface of the first electrode layer, and after a second annealing treatment, the second electrode layer is formed. The temperature of the first annealing treatment is 140℃~160℃, and the temperature of the second annealing treatment is 130℃~160℃.

10. The preparation method according to claim 8, characterized in that, The mass ratio of proton-acidified polyaniline to the first carbon material in the first electrode slurry is 1:10-15.

11. The preparation method according to claim 9, characterized in that, If the conductive polymer is polyaniline, then the preparation process of the first electrode slurry includes: Polyaniline, ammonium salt and protic acid are mixed and reacted to obtain protic acid-acidified polyaniline; The proton-acidified polyaniline, carbon material, dispersant, and binder are mixed and dissolved in a solvent to obtain the first electrode slurry.

12. The preparation method according to claim 11, characterized in that, The molar concentration of the protic acid is 0.1 mol / L to 0.5 mol / L.

13. The preparation method according to claim 11, characterized in that, The protic acid is selected from at least one of hydrochloric acid, sulfuric acid, and phosphoric acid, and the ammonium salt is selected from at least one of ammonium sulfate and ammonium chloride.

14. The preparation method according to claim 11, characterized in that, The dispersant is selected from at least one of polyvinylpyrrolidone, polyvinyl alcohol, hexadecanetrimethylammonium bromide and sodium dodecylbenzenesulfonate; the binder is selected from at least one of hydroxymethyl cellulose, polyacrylic acid and polyvinyl alcohol; the solvent is selected from at least one of isopropanol, diethyl ether, ethanol and chloroform.

15. A photovoltaic module, characterized in that, The photovoltaic module comprises the solar cell according to any one of claims 1 to 7, or the photovoltaic module comprises the solar cell prepared by the preparation method according to any one of claims 8 to 14.

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