Perovskite-silicon laminated solar cell, preparation method thereof and photovoltaic module

Abstract

The invention discloses a perovskite-silicon laminated solar cell, a preparation method thereof and a photovoltaic module, the perovskite-silicon laminated solar cell comprises a silicon bottom cell and a perovskite top cell arranged on the silicon bottom cell, the exposed side surface of the silicon bottom cell is provided with a first hydrogen enrichment layer, and the perovskite top cell is provided with a second hydrogen enrichment layer; wherein the perovskite top cell comprises a transparent conductive layer arranged away from the silicon bottom cell, and the second hydrogen enrichment layer at least comprises a first sub-layer arranged on the top surface, away from the silicon bottom cell, of the transparent conductive layer. The passivation effect of the outer edge region of the perovskite-silicon laminated cell can be effectively improved, so that the photoelectric conversion efficiency of the cell is improved.

Description

Technical Field

[0001] This application relates to the field of solar cells, and more particularly to a perovskite-silicon tandem solar cell and its fabrication method, as well as a photovoltaic module. Background Technology

[0002] Perovskite-silicon tandem solar cells have become a research hotspot due to their theoretical efficiency exceeding 45%. However, perovskite-silicon tandem solar cells still contain many defects, limiting further improvements in their photoelectric conversion efficiency. Summary of the Invention

[0003] To further improve the photoelectric conversion efficiency of perovskite-silicon tandem solar cells, this application provides a perovskite-silicon tandem solar cell, its fabrication method, and a photovoltaic module.

[0004] In a first aspect, embodiments of this application provide a perovskite-silicon tandem solar cell.

[0005] A perovskite-silicon tandem solar cell includes: a silicon base cell and a perovskite top cell disposed on the silicon base cell, wherein the exposed surface of the silicon base cell has a first hydrogen enrichment layer and the perovskite top cell has a second hydrogen enrichment layer.

[0006] The perovskite top cell includes a transparent conductive layer disposed away from the silicon bottom cell, and the second hydrogen enrichment layer includes at least a first sub-layer disposed on the top surface of the transparent conductive layer away from the silicon bottom cell.

[0007] As an optional implementation, in an embodiment of this application, the second hydrogen enrichment layer further includes a second sub-layer disposed on the exposed side surface of the transparent conductive layer, wherein the H element concentration of the second sub-layer is greater than the H element concentration of the first sub-layer.

[0008] As an optional implementation, in the embodiments of this application, the concentration of H element in the first sublayer is 0.1 at.% to 1 at.%; and / or, the concentration of H element in the second sublayer is 5 at.% to 15 at.%.

[0009] As an optional implementation, in the embodiments of this application, the H element concentration of the first hydrogen enrichment layer is greater than the H element concentration of the first sublayer.

[0010] As an optional implementation, in the embodiments of this application, the concentration of H element in the first hydrogen enrichment layer is 5 at.% to 15 at.%.

[0011] As an optional implementation, in an embodiment of this application, along a first direction, the perovskite top solar cell includes a composite layer, a first transport layer, a perovskite layer, a second transport layer, the transparent conductive layer, and a first electrode sequentially stacked on the silicon bottom solar cell. One of the first transport layer and the second transport layer is a nickel oxide hole transport layer, and the other is an electron transport layer. The first direction is the thickness direction of the silicon bottom solar cell.

[0012] The second hydrogen enrichment layer further includes a third sublayer disposed on the exposed side surface of the nickel oxide hole transport layer;

[0013] And / or,

[0014] The second transport layer is the electron transport layer, and a tin oxide buffer layer is further disposed between the electron transport layer and the transparent conductive layer. The second hydrogen enrichment layer also includes a fourth sub-layer disposed on the exposed surface of the tin oxide buffer layer.

[0015] As an optional implementation, in the embodiments of this application, Ni in the third sublayer 2+ The proportion is greater than that of Ni in the internal region of the nickel oxide hole transport layer. 2+ Percentage;

[0016] And / or,

[0017] Sn in the fourth sub-layer 2+ / Sn 4+ The ratio is greater than that of Sn in the internal region of the tin oxide buffer layer. 2+ / Sn 4+ ratio.

[0018] As an optional implementation, in the embodiments of this application, the silicon-based solar cell is a sliced ​​solar cell;

[0019] And / or,

[0020] In the second direction, the side surface of the perovskite top cell is recessed inward relative to the side surface of the silicon bottom cell to form a stepped structure, and the second direction is perpendicular to the thickness direction of the silicon bottom cell.

[0021] Secondly, this application provides a method for preparing a perovskite-silicon tandem solar cell.

[0022] A method for fabricating a perovskite-silicon tandem solar cell, as mentioned in the first aspect, includes the following steps:

[0023] The perovskite top cell, including the transparent conductive layer, is fabricated on the surface of the silicon bottom cell;

[0024] When the transparent conductive layer is exposed, hydrogen treatment is performed, the hydrogen treatment including:

[0025] A hydrogen source is introduced to perform edge coating and surface coating treatments, so that the exposed surface of the silicon bottom cell forms the first hydrogen enrichment layer, and the exposed surface of the perovskite top cell forms the second hydrogen enrichment layer, which includes at least the first sublayer.

[0026] As an optional implementation, in the embodiments of this application, the hydrogen treatment is performed using atomic layer deposition, and the edge coating treatment and the surface coating treatment are performed sequentially. The flow rate, temperature, and time of the hydrogen source used in the edge coating treatment step are greater than those of the hydrogen source used in the surface coating treatment step.

[0027] As an optional implementation, in the embodiments of this application, in the edge coating treatment step, the flow rate of the hydrogen source is 5 mL / min to 7 mL / min, the treatment temperature is 80℃ to 100℃, and the time is 40 min to 60 min; in the surface coating treatment step, the flow rate of the hydrogen source is 1 mL / min to 3 mL / min, the treatment temperature is 80℃ to 100℃, and the time is 20 min to 30 min.

[0028] As an optional implementation, in the embodiments of this application, the hydrogen source includes formic acid and / or acetic acid;

[0029] And / or,

[0030] The edge coating process and the surface coating process are performed in the same reaction chamber.

[0031] As an optional implementation, in the embodiments of this application, the perovskite top solar cell includes a composite layer, a first transport layer, a perovskite layer, a second transport layer, and a transparent conductive layer stacked sequentially. One of the first transport layer and the second transport layer is a nickel oxide hole transport layer, and the other is an electron transport layer. The first direction is the thickness direction of the silicon bottom solar cell.

[0032] After the hydrogen treatment, the second hydrogen enrichment layer includes a third sublayer formed on the exposed side surface of the nickel oxide hole transport layer;

[0033] The second transport layer is an electron transport layer, and a tin oxide buffer layer is further disposed between the electron transport layer and the transparent conductive layer. The second hydrogen enrichment layer includes a fourth sub-layer formed on the exposed side surface of the tin oxide buffer layer.

[0034] And / or,

[0035] The perovskite top cell also includes a first electrode disposed on the transparent conductive layer, and the hydrogen treatment is performed before or after the preparation of the first electrode.

[0036] Thirdly, embodiments of this application provide a photovoltaic module.

[0037] A photovoltaic module includes a solar cell as mentioned in the first aspect or a solar cell prepared by the preparation method mentioned in the second aspect.

[0038] Compared with the prior art, the beneficial effects of this application are as follows:

[0039] This application provides a perovskite-silicon tandem solar cell. By introducing a first hydrogen enrichment layer and a second sublayer on the exposed surface of the silicon base cell and the surface of the transparent conductive layer, respectively, hydrogen (H) is enriched on the exposed surface of the silicon base cell and the surface of the transparent conductive layer. This effectively suppresses edge leakage in the perovskite-silicon tandem solar cell, significantly improving its photoelectric conversion efficiency and stability. Specifically, the hydrogen enrichment layer, with its H enriched on the exposed surface of the silicon base cell, effectively passivates dangling bond defects on the exposed surface, suppressing non-radiative recombination and leakage. Simultaneously, the second hydrogen enrichment layer includes at least the first sublayer disposed on the top surface of the transparent conductive layer. This not only reduces the surface roughness of the transparent conductive layer, reducing leakage, but also improves carrier mobility and reduces carrier recombination losses, thereby effectively reducing the overall edge leakage of the perovskite-silicon solar cell and improving its stability and photoelectric conversion efficiency. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying 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.

[0041] Figure 1 This is a schematic diagram of the structure of the perovskite-silicon tandem solar cell disclosed in the embodiments of this application;

[0042] Figure 2 This is a schematic diagram illustrating the distribution structure of hydrogen elements in a transparent conductive layer, as disclosed in the embodiments of this application.

[0043] Figure 3 This is a schematic diagram of the stepped structure formed by the inward contraction of the perovskite top cell relative to the silicon bottom cell, as disclosed in the embodiments of this application.

[0044] Figure 4This is a schematic diagram of the structure of the first type of transparent conductive layer with the exposed state disclosed in the embodiments of this application;

[0045] Figure 5 This is a schematic diagram of the structure of the second type of transparent conductive layer in an exposed state disclosed in the embodiments of this application.

[0046] Icons: 100, Silicon substrate cell; 11, First hydrogen enrichment layer; 12, Second electrode;

[0047] 200. Perovskite top cell; 21. Second hydrogen enrichment layer; 211. First sublayer; 212. Second sublayer; 213. Third sublayer; 214. Fourth sublayer; 22. Transparent conductive layer; 23. Composite layer; 24. Nickel oxide hole transport layer; 25. Perovskite layer; 26. Electron transport layer; 27. First electrode; 28. Tin oxide buffer layer; 29. ​​Antireflection layer. Detailed Implementation

[0048] 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.

[0049] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] In perovskite-silicon tandem solar cells, silicon bottom cells, such as heterojunction bottom cells, are typically used for long-wavelength absorption. The perovskite top cell complements the silicon bottom cell to better improve the photoelectric conversion efficiency of the solar cell. Due to limitations in perovskite layer equipment development, the fabrication process of perovskite-silicon tandem solar cells generally involves first dividing the entire heterojunction cell into fixed small-area units using laser cutting to serve as bottom cells. However, the inventors discovered that the exposed surface of the silicon bottom cell is prone to dangling bond defects, especially those introduced into the cut surfaces created by the cutting process, leading to severe non-radiative recombination on the exposed surface. Furthermore, the inventors also noted that defects easily form on the surfaces of various functional layers in the perovskite top cell (e.g., unpassivated oxides or microcracks are easily introduced into the nickel oxide hole transport layer and tin oxide hole transport layer). These defects can easily cause leakage at the cell edges, resulting in reduced photoelectric conversion efficiency and stability of the perovskite-silicon tandem solar cell.

[0054] Defect passivation treatment for perovskite-silicon tandem solar cells is usually performed on specific functional films (such as using solution passivating agents), and mainly focuses on passivating the bulk defects of the functional film or the interface contact defects between the functional film and adjacent functional films. It does not pay attention to the outer edge area that needs to be covered by the multilayer stacked structure (i.e., the surface defects of the exposed side of the silicon bottom cell, the surface defects of the functional film of the perovskite top cell, etc., mentioned above).

[0055] In order to reduce the defects of perovskite tandem solar cells and provide better passivation effect for perovskite-silicon tandem solar cells, this application provides a perovskite-silicon tandem solar cell.

[0056] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.

[0057] In a first aspect, embodiments of this application provide a perovskite-silicon tandem solar cell.

[0058] Reference Figure 1 A perovskite-silicon tandem solar cell includes: a silicon bottom cell 100 and a perovskite top cell 200 disposed on the silicon bottom cell 100. The exposed surface of the silicon bottom cell 100 has a first hydrogen enrichment layer 11, and the perovskite top cell 200 has a second hydrogen enrichment layer 21.

[0059] The perovskite top cell 200 includes a transparent conductive layer 22 disposed away from the silicon bottom cell 100, and the second hydrogen enrichment layer 21 includes at least a first sub-layer 211 disposed on the top surface of the transparent conductive layer 22 away from the silicon bottom cell 100.

[0060] This application introduces a first hydrogen enrichment layer 11 and a second sub-layer 212 on the exposed surface of the silicon base cell 100 and the surface of the transparent conductive layer 22, respectively, so that hydrogen (H) is enriched on the exposed surface of the silicon base cell 100 and the surface of the transparent conductive layer 22, effectively suppressing the edge leakage problem of the perovskite-silicon tandem solar cell and greatly improving the photoelectric conversion efficiency and stability of the perovskite-silicon tandem solar cell. Specifically, the H element in the first hydrogen enrichment layer 11 is enriched on the exposed surface of the silicon base cell 100, which can effectively passivate dangling bond defects on the exposed surface of the silicon base cell 100 and suppress non-radiative recombination and leakage. Simultaneously, the H element in the second hydrogen enrichment layer 21 is also enriched on the top surface of the transparent conductive layer 22, which not only reduces the surface roughness of the transparent conductive layer 22 and reduces leakage, but also improves carrier mobility and reduces carrier mobility recombination loss, thereby effectively reducing the overall edge leakage of the perovskite-silicon solar cell and improving its stability and photoelectric conversion efficiency.

[0061] In the embodiments of this application, the hydrogen-enriched layer is a region where hydrogen atoms are relatively abundant, with a higher hydrogen atom concentration than adjacent regions. Hydrogen atoms exist in this region in interstitial or bonded forms, filling lattice defects or dangling bonds, thus passivating defects. For example, in... Figure 1 In the above, the exposed surface of the silicon bottom cell 100 has a first hydrogen enrichment layer 11, which means that the hydrogen atom concentration on the exposed surface of the silicon bottom cell 100 is higher than the hydrogen atom concentration inside the silicon bottom cell 100.

[0062] In this embodiment, the second hydrogen enrichment layer 21 of the perovskite top cell 200 includes at least a first sub-layer 211 disposed on the top surface of the transparent conductive layer 22. This means that the second hydrogen enrichment layer 21 can be disposed only on the top surface of the transparent conductive layer 22, or it can be disposed at other locations of the perovskite top cell 200. For example, the second hydrogen enrichment layer 21 can be disposed on the entire exposed surface of the perovskite top cell 200.

[0063] In the embodiments of this application, the top surface refers to the surface region of any functional film layer away from its bottom. The side surface refers to the perimeter region of any functional film layer, located between the top surface and the bottom surface (i.e., the bottom surface opposite to the top surface). For example, in Figure 1In this context, the top surface of the transparent conductive layer 22 refers to its upper surface. Furthermore, the top surface of the transparent conductive layer 22 can be either an exposed top surface or a non-exposed top surface. For example, when the transparent conductive layer 22 is the outermost layer of a perovskite-silicon tandem solar cell, its top surface is an exposed top surface; when the outermost layer of the perovskite-silicon tandem solar cell is another functional layer (e.g., an anti-reflection layer is provided on the top surface of the transparent conductive layer 22), the top surface of the transparent conductive layer 22 is not an exposed top surface.

[0064] Reference Figure 2 In some embodiments, the second hydrogen enrichment layer 21 further includes a second sub-layer 212 disposed on the exposed side surface of the transparent conductive layer 22, wherein the H element concentration of the second sub-layer 212 is greater than the H element concentration of the first sub-layer 211.

[0065] like Figure 2 As shown, by setting hydrogen enrichment layers of different concentrations on the side and top surfaces of the transparent conductive layer 22, the defect passivation effect can be effectively improved. The second sub-layer 212 has a higher hydrogen concentration, which can more effectively passivate dangling bonds and defects on the exposed side surface of the transparent conductive layer 22, improving the stability of the edge region; while the relatively low hydrogen concentration of the first sub-layer 211 can ensure a certain passivation effect while forming a good bandgap match with the subsequent electrode, reducing the interface contact resistance. This design optimizes the edge passivation effect while taking into account the interface performance between the electrode and the transparent conductive layer 22, further improving the overall performance of the battery.

[0066] In some embodiments, the concentration of H element in the first sublayer 211 is 0.1 at.% to 1 at.% (at.% is atomic percentage); and / or, the concentration of H element in the second sublayer 212 is 5 at.% to 15 at.%.

[0067] By controlling the hydrogen concentration within the aforementioned range, targeted defect passivation can be achieved in different regions. For example, optimizing the hydrogen concentration in the first sublayer 211 ensures an optimal balance in the defect passivation effect on the top surface; while setting a higher hydrogen concentration in the second sublayer 212 further enhances the stability of the side surfaces. This limitation of the concentration range not only improves the passivation effect but also avoids the decomposition of the perovskite layer 25 or other negative impacts that may result from excessively high hydrogen concentrations, thereby maximizing battery efficiency and stability while protecting the structure of the perovskite layer 25.

[0068] For example, the H element concentration in the first sublayer 211 can be 0.1 at.%, 0.5 at.%, 0.7 at.%, 0.9 at.%, or 1 at.%, etc., and the H element concentration in the second sublayer 212 can be 5 at.%, 7 at.%, 10 at.%, 13 at.%, or 15 at.%, etc.

[0069] In some embodiments, the H element concentration of the first hydrogen enrichment layer 11 is greater than the H element concentration of the first sublayer 211.

[0070] By setting hydrogen enrichment layers of different concentrations on the exposed surface of the silicon bottom cell 100 and the surface of the transparent conductive layer 22 of the perovskite top cell 200, a layered passivation effect is achieved, satisfying the different hydrogen concentration requirements for passivation in different regions. Simultaneously, this arrangement allows for a lower hydrogen source concentration acting on the perovskite layer 25 during hydrogen treatment, which helps reduce the potential decomposition of the perovskite layer 25 caused by excessively high hydrogen concentrations.

[0071] In some embodiments, the concentration of H in the first hydrogen enrichment layer 11 is 5 at.% to 15 at.%.

[0072] By controlling the hydrogen concentration on the exposed surface of the silicon substrate 100 within the aforementioned range, the passivation effect of dangling bonds on the exposed surface of the silicon substrate 100 is optimized. A higher hydrogen concentration can more effectively passivate dangling bonds on the side surface of the silicon substrate 100, reducing non-radiative recombination, while avoiding other potential problems caused by excessive concentration (such as over-passivation or material performance degradation). This optimized concentration range design provides a stable passivation effect for the edge region of the silicon substrate 100, significantly improving the overall performance of the cell.

[0073] For example, the H element concentration in the first hydrogen enrichment layer 11 can be 5 at.%, 7 at.%, 10 at.%, 13 at.%, or 15 at.%, etc.

[0074] Reference Figure 1 In some embodiments, along a first direction, the perovskite top solar cell 200 includes a composite layer 23, a first transport layer, a perovskite layer 25, a second transport layer, a transparent conductive layer 22, and a first electrode 27 sequentially stacked on a silicon bottom solar cell 100. One of the first and second transport layers is a nickel oxide hole transport layer 24, and the other is an electron transport layer 26. The first direction is the thickness direction of the silicon bottom solar cell 100. Figure 1 In the X direction, where:

[0075] The second hydrogen enrichment layer 21 also includes a third sublayer 213 disposed on the exposed side surface of the nickel oxide hole transport layer 24;

[0076] And / or,

[0077] The second transport layer is an electron transport layer 26. A tin oxide buffer layer 28 is also provided between the electron transport layer 26 and the transparent conductive layer 22. The second hydrogen enrichment layer 21 also includes a fourth sub-layer 214 provided on the exposed surface of the tin oxide buffer layer 28.

[0078] By introducing a third sublayer 213 and a fourth sublayer 214 on the exposed surfaces of the nickel oxide hole transport layer 24 and the tin oxide buffer layer 28, the surface defect passivation effect of these films can be further optimized.

[0079] Furthermore, the thickness of the nickel oxide hole transport layer 24 can be 10 nm to 20 nm, and the thickness of the tin oxide buffer layer 28 can be 10 nm to 20 nm.

[0080] The silicon-based solar cell 100 may be a heterojunction solar cell, etc. This silicon-based solar cell 100 can be a textured solar cell with a pyramidal textured surface, the pyramid height of which can be 2μm to 3μm. The silicon-based solar cell 100 has a second electrode 12 corresponding to the first electrode 27. Both the first electrode 27 and the second electrode 12 are made of a metallic material with good electrical conductivity, such as silver, copper, or zinc. The first electrode 27 and the second electrode 12 are also used to collect photogenerated carriers, ensuring that the charge can be smoothly discharged from the interior of the solar cell, promoting the efficient operation of the solar cell.

[0081] The composite layer 23 can be made of any one of indium tin oxide, indium tungsten oxide, and indium cadmium oxide, with a thickness of 20 nm to 50 nm, and can be prepared by physical vapor deposition.

[0082] The hole transport layer is made of inorganic materials, such as nickel oxide (NiO). x It can be an organic material, such as Spiro-TTB (2,2',7,7'-tetra(N,N-di-tolyl)aMino-spiro-bifluor,2,2',7,7'-tetra(di-p-tolylamino)spiro-9,9'-difluorene), with a thickness of 10 nm to 30 nm, which can be deposited by PVD or vacuum deposition.

[0083] The perovskite layer 25 is prepared by first depositing a framework layer by evaporation, and then coating the framework layer with a cationic solution. When depositing the framework layer, a dual-source co-evaporation process is used to deposit PbI2 and CsBr, with an evaporation rate ratio of (7:1) to (10:1). The evaporation rate error during the evaporation process should be less than 5%, and the film thickness uniformity should be less than 5%. On the framework layer, a cationic solution is spin-coated onto the surface of the framework layer using a spin-coating process. The cationic solution material is a mixed solution of formamidine, methyl bromide, and chloromethylamine, or a mixed solution of formamidine, methyl bromide, and chloromethylamine. The solvent can be anhydrous ethanol, isopropanol, etc. Preferably, in the cationic solution, the concentration of formamidine is 0.3M to 0.6M, the concentration of methyl bromide is 0.1M to 0.2M, and the concentration of chloromethylamine is 0.05M to 0.15M. The spin-coating speed is 3000rpm to 6000rpm, the spin-coating time is 30s, the humidity of the spin-coating environment is less than 10%, and the temperature is 25℃. After spin-coating, annealing is performed under conditions of 5% to 40% humidity, the annealing temperature is 100℃ to 150℃, and the annealing time is 15min to 30min. During the annealing process, the cationic solution reacts with the framework layer to crystallize and form a perovskite layer 25 with a thickness of 450nm to 600nm.

[0084] The material of electron transport layer 26 can be C 60 The thickness is 15nm to 20nm, and the electron transport layer 26 can be prepared by vapor deposition at a rate of [missing information].

[0085] The transparent conductive layer 22 can be made of indium tin oxide, indium tungsten oxide, or indium cadmium oxide, with a thickness of 50 nm to 120 nm, and can be prepared by physical vapor deposition.

[0086] In addition, a passivation layer may be provided between the electron transport layer 26 and the perovskite layer 25 or between the hole transport layer and the perovskite layer 25, and an anti-reflection layer 29 may be provided on the side of the transparent conductive layer 22 away from the silicon bottom cell 100 to further optimize the performance of the perovskite top cell 200.

[0087] Furthermore, in some embodiments, Ni in the third sublayer 213 2+ The proportion is greater than that of Ni in the internal region of nickel oxide hole transport layer 24. 2+ Proportion. Ni in the third sublayer 213 2+ The increased proportion can improve the stability of the nickel oxide hole transport layer 24 and reduce edge leakage.

[0088] In some embodiments, Sn in the fourth sublayer 214 2+ / Sn 4+ The ratio is greater than that of Sn in the internal region of the tin oxide buffer layer 28. 2 + / Sn 4+ Ratio. Sn in the fourth sublayer 2142+ / Sn 4+ Optimizing the ratio can improve the performance of the tin oxide buffer layer 28, reduce surface roughness, and increase carrier mobility.

[0089] These improvements further enhance the photoelectric conversion efficiency and stability of perovskite-silicon tandem solar cells.

[0090] In some embodiments, the silicon-based solar cell 100 is a sliced ​​cell.

[0091] Sliced ​​solar cells refer to solar cells that are cut into smaller or more specific shapes during manufacturing. The exposed surfaces of sliced ​​solar cells have more new dangling bonds and higher rates of non-radiative recombination, resulting in a higher risk of leakage. This application addresses this by creating a first hydrogen enrichment layer 11 on the exposed surfaces of the sliced ​​solar cells, effectively passivating the dangling bonds, significantly reducing leakage risk, and improving solar cell performance.

[0092] Reference Figure 3 In some embodiments, in the second direction, the side surface of the perovskite top cell 200 is recessed inward relative to the side surface of the silicon bottom cell 100 to form a stepped structure. The second direction is perpendicular to the thickness direction of the silicon bottom cell 100. Figure 3 in the Y direction.

[0093] Figure 3 The stepped structure shown enables synergistic optimization of the silicon bottom cell 100 and the perovskite top cell 200 during the passivation process. During hydrogen treatment, the side surface of the silicon bottom cell 100 is directly exposed to a high-concentration hydrogen source environment, allowing hydrogen atoms to diffuse sufficiently to the exposed surface defects of the silicon bottom cell 100, passivating dangling bonds and improving surface electrical performance. Simultaneously, the inward-curving side surface of the perovskite top cell 200 helps to extend the lateral diffusion path of hydrogen atoms to the perovskite layer 25, significantly reducing the hydrogen concentration gradient near the side surface of the perovskite top cell 200, thereby preventing excessive hydrogen infiltration into the perovskite lattice and causing structural decomposition or ion migration. This design ensures the passivation effect of the exposed surface of the silicon bottom cell 100 while also considering the compatibility requirements of the perovskite material with hydrogen sensitivity, ultimately achieving a stable improvement in the overall performance of the perovskite-silicon tandem solar cell.

[0094] The inventors also discovered that while traditional passivation techniques such as plasma treatment used in hydrogen passivation can repair some defects, high-energy particle bombardment or high-temperature environments easily lead to the decomposition of the perovskite layer 25 (e.g., MA). + FA +Ion migration, lattice distortion, and even phase separation can occur. For example, conventional hydrogen passivation at temperatures above 200°C directly causes an efficiency degradation of more than 5% in the perovskite layer 25. It is evident that in perovskite-silicon tandem solar cells, there is a certain contradiction between the need to passivate defects in the outer edge region and the thermochemical sensitivity of the perovskite layer 25, making it difficult to balance defect repair and protection of the perovskite layer 25, thus leading to a bottleneck in efficiency improvement. Therefore, in a second aspect, this application provides a method for fabricating a perovskite-silicon tandem solar cell to overcome the aforementioned shortcomings.

[0095] The perovskite-silicon tandem solar cell fabrication method mentioned in the first aspect includes the following steps:

[0096] A perovskite top cell 200 including a transparent conductive layer 22 is fabricated on the surface of a silicon bottom cell 100;

[0097] When the transparent conductive layer 22 is exposed, hydrogen treatment is performed, which includes:

[0098] A hydrogen source is introduced to perform edge coating and surface coating treatments, so that a first hydrogen enrichment layer 11 is formed on the exposed surface of the silicon bottom cell 100, and a second hydrogen enrichment layer 21, including at least a first sublayer 211, is formed on the exposed surface of the perovskite top cell 200.

[0099] The hydrogen treatment in this application includes two processes: edge-wrapping coating and surface coating. After hydrogen treatment, a first hydrogen enrichment layer 11 is formed on the exposed surface of the silicon bottom cell 100, and a second hydrogen enrichment layer 21 is formed on the perovskite top cell 200. The edge-wrapping coating mainly repairs dangling bonds and defects on the exposed surface of the silicon bottom cell 100. Some of the hydrogen source will further diffuse to the exposed surfaces of other films in the perovskite top cell 200, thereby improving the passivation performance of some films in the perovskite top cell 200, such as the nickel oxide hole transport layer 24. The surface coating mainly optimizes the surface performance of the transparent conductive layer 22. During the surface coating process, some of the hydrogen source will also further diffuse to the exposed surfaces of other films in the perovskite top cell 200, thereby improving the passivation performance of some films in the perovskite top cell 200, such as the nickel oxide hole transport layer 24. This processing technology not only improves the passivation effect, but also avoids potential damage to the perovskite layer 25 from high-energy particle bombardment or high-temperature environments, ensuring the integrity of the battery structure and significantly improving the photoelectric conversion efficiency and stability of the battery.

[0100] In some embodiments, hydrogen treatment is performed using atomic layer deposition, with edge coating and surface coating performed sequentially. In the edge coating step, the hydrogen source flow rate is 5 mL / min to 7 mL / min, the temperature is 80°C to 100°C, and the time is 40 min to 60 min. In the surface coating step, the hydrogen source flow rate is 1 mL / min to 3 mL / min, the temperature is 80°C to 100°C, and the time is 20 min to 30 min.

[0101] Atomic layer deposition (ALD) is used to deposit hydrogen sources, which fully leverages the advantages of ALD in precisely controlling the flow path, distribution, and reaction kinetics of reactant gases within the chamber. This allows for stepwise control of the hydrogen source flow field, enabling selective deposition in specific regions. Therefore, without damaging the perovskite layer 25 structure, effective passivation of specific regions in the silicon substrate 100 and the transparent conductive layer 22 can be achieved, resulting in a significant improvement in the photoelectric conversion efficiency of the solar cell.

[0102] Furthermore, this embodiment of the application defines the hydrogen source flow rate, temperature, and time for edge-to-edge coating and surface coating. By precisely controlling these process parameters, targeted defect passivation can be achieved in different regions. For example, the high hydrogen flow rate and longer processing time of the edge-to-edge coating process can more effectively passivate the dangling bonds on the exposed surface of the silicon bottom cell 100; while the low hydrogen flow rate and shorter processing time of the surface coating process avoid over-processing of the perovskite layer 25, protecting its structural stability. This optimized design of process parameters ensures that the effect of hydrogen treatment is maximized, while taking into account process efficiency and cost.

[0103] In some embodiments, the hydrogen source includes formic acid and / or acetic acid.

[0104] By selecting a hydrogen source that can provide protonated hydrogen at low temperatures, the high-temperature conditions (above 200°C) required for traditional hydrogen processing are avoided, thus preventing the decomposition and efficiency degradation of the perovskite layer 25. Formic acid and acetic acid can effectively provide protonated hydrogen at temperatures below 100°C, allowing hydrogen processing to be carried out at lower temperatures and protecting the structural integrity of the perovskite layer 25. This choice of hydrogen source not only improves the passivation effect but also reduces process energy consumption and increases the fabrication efficiency of the battery.

[0105] In some embodiments, the edge coating process and the surface coating process are performed in the same reaction chamber.

[0106] By reducing equipment changeover time and avoiding the introduction of impurities, process efficiency and passivation effects are significantly improved. Sequential edge coating and surface coating within the same reaction chamber maintain a consistent process environment, avoiding potential contamination caused by chamber changes or cleaning, and ensuring the uniformity and stability of the first hydrogen enrichment layer 11 and the second hydrogen enrichment layer 21. This design not only simplifies the process flow but also reduces production costs and improves battery fabrication efficiency.

[0107] In some embodiments, along a first direction, the perovskite top solar cell 200 includes a composite layer 23, a first transport layer, a perovskite layer 25, a second transport layer, and a transparent conductive layer 22 stacked sequentially. One of the first and second transport layers is a nickel oxide hole transport layer 24, and the other is an electron transport layer 26. The first direction is the thickness direction of the silicon bottom solar cell 100.

[0108] After hydrogen treatment, the second hydrogen enrichment layer 21 includes a third sublayer 213 formed on the exposed side surface of the nickel oxide hole transport layer 24.

[0109] The second transport layer is an electron transport layer 26. A tin oxide buffer layer 28 is also disposed between the electron transport layer 26 and the transparent conductive layer 22. The second hydrogen enrichment layer 21 includes a fourth sublayer 214 formed on the exposed surface of the tin oxide buffer layer 28.

[0110] During the edge coating and surface coating processes, the hydrogen source also partially acts on the exposed surface of the perovskite top cell 200, thereby passivating the exposed surfaces of the nickel oxide hole transport layer 24 and the tin oxide buffer layer 28, forming a third sub-layer 213 on the exposed surface of the nickel oxide hole transport layer 24 and a fourth sub-layer 214 on the exposed surface of the tin oxide buffer layer 28.

[0111] In some embodiments, the perovskite top cell 200 further includes a first electrode 27 disposed on the transparent conductive layer 22, wherein hydrogen treatment is performed before or after the preparation of the first electrode 27.

[0112] In the fabrication process of perovskite-silicon tandem solar cells, after the silicon bottom cell 100 is fabricated, a composite layer 23, a first transport layer, a perovskite layer 25, a second transport layer, a transparent conductive layer 22, and a first electrode 27 are sequentially fabricated on its surface. These layers together constitute the perovskite top cell 200. For example... Figure 4 As shown, after the transparent conductive layer 22 is fabricated, the layer is exposed, or as... Figure 5As shown, after the first electrode 27 is fabricated, most of the transparent conductive layer 22 is exposed. At this point, hydrogen treatment allows the hydrogen source to act on the surface of the transparent conductive layer 22, optimizing its passivation effect. After hydrogen treatment, an antireflection layer 29, such as a LiF layer or a MgF2 layer, can be further deposited on the surface of the transparent conductive layer 22 to optimize the antireflection effect and further improve the overall performance of the perovskite-silicon tandem solar cell.

[0113] By flexibly adjusting the timing of hydrogen treatment, the interface performance between the first electrode 27 and the transparent conductive layer 22 can be optimized. Performing hydrogen treatment after electrode fabrication protects the electrode material (such as a silver electrode) from oxidation, improving electrode stability; while performing hydrogen treatment before electrode fabrication further optimizes the surface properties of the transparent conductive layer 22 and reduces interfacial contact resistance. This provides more options for actual production, ensuring optimal battery performance.

[0114] Thirdly, embodiments of this application provide a photovoltaic module.

[0115] A photovoltaic module includes a solar cell as mentioned in the first aspect or a solar cell prepared by the preparation method mentioned in the second aspect.

[0116] The technical solution of this application will be further described below with reference to more specific embodiments.

[0117] Example 1

[0118] This application provides a method for fabricating a perovskite-silicon tandem solar cell, comprising the following steps:

[0119] Provides sliced ​​heterojunction bottom cells;

[0120] Fabricating a perovskite top cell on the light-receiving side of a sliced ​​heterojunction bottom cell includes:

[0121] The composite layer was prepared by magnetron sputtering and deposited on the surface of the sliced ​​heterojunction bottom cell. The composite layer was made of indium tin oxide and had a thickness of 20 nm.

[0122] A hole transport layer was prepared by magnetron sputtering and deposited on the surface of the composite layer-away slice heterojunction bottom cell. The hole transport layer was made of nickel oxide and had a thickness of 15 nm.

[0123] Hole modification was prepared by solution method, in which an ethanol solution of 2PACz was spin-coated onto the surface of the hole transport layer opposite to the sliced ​​heterojunction bottom cell to form a monolayer;

[0124] A two-step method was used to prepare the perovskite layer. A framework layer with a thickness of 400 nm was prepared by thermal evaporation at a co-evaporation rate of PbI2:CsBr = 10:1. A cationic solution was then coated onto the framework layer for reaction. The cationic solution was formed by dissolving FAI, MABr, and MACl in 1 mL of ethanol at a mass ratio of 10:1:0.2. The mixture was then annealed at 150 °C for 20 min to form the perovskite layer.

[0125] A passivation layer was prepared by thermal evaporation and deposited on the side of the perovskite layer away from the sliced ​​silicon heterojunction bottom cell. The material of the passivation layer was LiF and the thickness was 2 nm.

[0126] The electron transport layer was prepared by thermal evaporation and deposited on the side of the passivation layer away from the bottom of the heterojunction cell. The material of the electron transport layer was C. 60 The thickness is 15nm;

[0127] A buffer layer was prepared by atomic layer deposition and deposited on the side of the electron transport layer away from the sliced ​​heterojunction bottom cell. The buffer layer was made of tin oxide and had a thickness of 25 nm.

[0128] A transparent conductive layer was prepared by magnetron sputtering and deposited on the side of the buffer layer away from the bottom cell of the sliced ​​heterojunction. The transparent conductive layer was made of indium zinc oxide and had a thickness of 110 nm.

[0129] Hydrogen treatment using atomic layer deposition includes the following steps:

[0130] Edge coating treatment: Formic acid is introduced as a hydrogen source, and the hydrogen source is used to coat the exposed surface of the sliced ​​heterojunction bottom cell. The flow rate of the hydrogen source is 5 mL / min, the temperature is 100℃, and the treatment time is 50 min.

[0131] Surface coating treatment: Formic acid is then introduced as a hydrogen source, and the hydrogen source is used to coat the surface of the transparent conductive layer. The flow rate of the hydrogen source is 3 mL / min, the temperature is 100℃, and the treatment time is 20 min.

[0132] A first electrode is prepared, which is a silver electrode, and an ohmic contact is formed between the first electrode and the indium tin oxide transparent conductive layer.

[0133] Prepare lithium fluoride antireflection layer.

[0134] Example 2

[0135] This application provides a method for preparing a perovskite-silicon tandem solar cell. The difference from Example 1 is that after the first electrode is prepared, hydrogen treatment is performed. The rest is the same as in Example 1.

[0136] Example 3

[0137] This application provides a method for fabricating a perovskite-silicon tandem solar cell, which differs from Example 1 in that the process conditions for edge coating and surface coating are changed. Specifically:

[0138] During the edge coating process, the hydrogen source flow rate was 3 mL / min, the temperature was 100℃, and the processing time was 20 min.

[0139] During the surface coating process, the hydrogen source flow rate was 5 mL / min, the temperature was 100℃, and the treatment time was 50 min.

[0140] Everything else remains the same as in Example 1.

[0141] Comparative Example 1

[0142] This application provides a comparative method for preparing a perovskite-silicon tandem solar cell. The difference between this method and Example 1 is that hydrogen treatment is not performed, while the rest remains the same as Example 1.

[0143] Experiment 1

[0144] The average hydrogen concentration of the first sublayer and the second sublayer in the first hydrogen enrichment layer and the second hydrogen enrichment layer was detected by FIB (Focused Ion Beam)-mass spectrometry. The detection results are shown in Table 1.

[0145] XPS (X-ray photoelectron spectroscopy) was used to study the exposed surface region (i.e., the third sublayer) and the internal region of the Ni oxide hole transport layer. 2+ The content was tested.

[0146] XPS was used to analyze the Sn content in the exposed surface region (i.e., the fourth sublayer) of the tin oxide buffer layer. 2+ / Sn 4+ The content was tested.

[0147] The test results of the above embodiments and comparative examples are shown in Table 1.

[0148] Table 1

[0149]

[0150]

[0151] Compared to Comparative Example 1 without hydrogen treatment, Examples 1 and 2 showed a significant increase in hydrogen concentration in the first hydrogen enrichment layer, the first sublayer, and the second sublayer. This demonstrates that hydrogen treatment on the solar cell surface successfully constructs the first and second hydrogen enrichment layer structures. Furthermore, in the nickel oxide hole transport layer, the exposed surface region of Ni... 2+The nickel content is significantly higher compared to the internal region, indicating that hydrogen treatment not only effectively introduces the first and second hydrogen enrichment layers, but also significantly alters the chemical state of the exposed surface of the nickel oxide hole transport layer, leading to Ni... 2 + Accumulation in the surface region. This demonstrates that hydrogen treatment effectively improves the stability of the nickel oxide hole transport layer. This enhanced stability, especially in exposed surface regions susceptible to environmental influences, is key to reducing edge leakage in solar cells.

[0152] Experiment 2

[0153] Solar cell performance testing

[0154] The performance of perovskite solar cells was tested using the Wavelabs solar simulator under the following conditions: AM1.5, 1000 W / m. 2 The test environment temperature was 25℃. Before testing, the light source was calibrated to simulate sunlight intensity using a standard silicon solar cell. The open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency of the corresponding perovskite solar cells were recorded.

[0155] The test results of the above embodiments and comparative examples are shown in Table 2.

[0156] Table 2

[0157]

[0158] A comparison of the data from Example 1 and Comparative Example 1 in Table 2 shows that, compared to Comparative Example 1, Example 1 exhibits significant improvements in open-circuit voltage, fill factor, and photoelectric conversion efficiency. This comparison fully demonstrates that treating the surface of a solar cell with hydrogen to form a first hydrogen-rich layer and a second hydrogen-rich layer can effectively passivate surface defects, thereby improving the overall performance of the cell.

[0159] Further comparison of the data from Example 1 and Example 2 reveals that although Example 2 also underwent hydrogen treatment, its fill factor and final photoelectric conversion efficiency were slightly lower than those of Example 1. This indicates that hydrogen treatment in Example 1, performed before the first electrode fabrication was completed, could better improve the electrical performance of the solar cell. However, hydrogen treatment performed after the first electrode fabrication was completed resulted in a relatively large contact resistance between the first electrode and the transparent conductive layer, leading to a decrease in the first electrode's carrier collection efficiency.

[0160] Comparing the data from Examples 1 and 3 reveals that the open-circuit voltage and fill factor of the solar cell in Example 1 are improved compared to Example 3. This indicates that using a higher concentration of hydrogen source for edge-coating and a lower concentration for surface coating can better improve the passivation performance of the heterojunction bottom cell and the transparent conductive layer. When a higher concentration of hydrogen source is used for surface coating and a lower concentration for edge-coating, the passivation effect of the heterojunction bottom cell and the transparent conductive layer is reduced, and the performance of the perovskite layer is impaired. Ultimately, the photoelectric conversion efficiency improvement of the solar cell in Example 3 is significantly less than that in Example 1.

[0161] The perovskite-silicon tandem solar cell, its preparation method, and photovoltaic module disclosed in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the perovskite-silicon tandem solar cell, its preparation method, photovoltaic module, and its core ideas 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 perovskite-silicon tandem solar cell, characterized in that, include: A silicon-based solar cell and a perovskite-based solar cell disposed on the silicon-based solar cell, wherein the exposed surface of the silicon-based solar cell has a first hydrogen enrichment layer and the perovskite-based solar cell has a second hydrogen enrichment layer. The perovskite top cell includes a transparent conductive layer disposed away from the silicon bottom cell, and the second hydrogen enrichment layer includes at least a first sub-layer disposed on the top surface of the transparent conductive layer away from the silicon bottom cell.

2. The perovskite-silicon tandem solar cell according to claim 1, characterized in that, The second hydrogen enrichment layer further includes a second sub-layer disposed on the exposed side surface of the transparent conductive layer, wherein the H element concentration of the second sub-layer is greater than that of the first sub-layer.

3. The perovskite-silicon tandem solar cell according to claim 2, characterized in that, In the first sublayer, the concentration of H element is 0.1 at.% to 1 at.%; and / or, in the second sublayer, the concentration of H element is 5 at.% to 15 at.%.

4. The perovskite-silicon tandem solar cell according to claim 1, characterized in that, The H element concentration of the first hydrogen enrichment layer is greater than that of the first sublayer.

5. The perovskite-silicon tandem solar cell according to claim 4, characterized in that, In the first hydrogen enrichment layer, the concentration of H element is 5 at.% to 15 at.%.

6. The perovskite-silicon tandem solar cell according to claim 1, characterized in that, Along the first direction, the perovskite top solar cell includes a composite layer, a first transport layer, a perovskite layer, a second transport layer, the transparent conductive layer, and a first electrode, sequentially stacked on the silicon bottom solar cell. One of the first and second transport layers is a nickel oxide hole transport layer, and the other is an electron transport layer. The first direction is the thickness direction of the silicon bottom solar cell. The second hydrogen enrichment layer further includes a third sublayer disposed on the exposed side surface of the nickel oxide hole transport layer; And / or, The second transport layer is the electron transport layer, and a tin oxide buffer layer is further disposed between the electron transport layer and the transparent conductive layer. The second hydrogen enrichment layer also includes a fourth sub-layer disposed on the exposed surface of the tin oxide buffer layer.

7. The perovskite-silicon tandem solar cell according to claim 6, characterized in that, Ni in the third sublayer 2+ The proportion is greater than that of Ni in the internal region of the nickel oxide hole transport layer. 2+ Percentage; And / or, Sn in the fourth sub-layer 2+ / Sn 4+ The ratio is greater than that of Sn in the internal region of the tin oxide buffer layer. 2+ / Sn 4+ ratio.

8. The perovskite-silicon tandem solar cell according to any one of claims 1-7, characterized in that, The silicon-based battery is a sliced ​​battery; And / or, In the second direction, the side surface of the perovskite top cell is recessed inward relative to the side surface of the silicon bottom cell to form a stepped structure, and the second direction is perpendicular to the thickness direction of the silicon bottom cell.

9. A method for fabricating a perovskite-silicon tandem solar cell, characterized in that, The method for fabricating a perovskite-silicon tandem solar cell as described in any one of claims 1-8 includes the following steps: The perovskite top cell, including the transparent conductive layer, is fabricated on the surface of the silicon bottom cell; When the transparent conductive layer is exposed, hydrogen treatment is performed, the hydrogen treatment including: A hydrogen source is introduced to perform edge coating and surface coating treatments, so that the exposed surface of the silicon bottom cell forms the first hydrogen enrichment layer, and the exposed surface of the perovskite top cell forms the second hydrogen enrichment layer, which includes at least the first sublayer.

10. The method for preparing a perovskite-silicon tandem solar cell according to claim 9, characterized in that, The hydrogen treatment is performed using atomic layer deposition, and the edge coating treatment and the surface coating treatment are performed sequentially. The flow rate, temperature and time of the hydrogen source used in the edge coating treatment step are greater than those of the hydrogen source used in the surface coating treatment step.

11. The method for preparing a perovskite-silicon tandem solar cell according to claim 10, characterized in that, In the edge coating process, the flow rate of the hydrogen source is 5 mL / min to 7 mL / min, the processing temperature is 80℃ to 100℃, and the time is 40 min to 60 min. In the surface coating process, the flow rate of the hydrogen source is 1 mL / min to 3 mL / min, the processing temperature is 80℃ to 100℃, and the time is 20 min to 30 min.

12. The method for preparing a perovskite-silicon tandem solar cell according to claim 11, characterized in that, The hydrogen source includes formic acid and / or acetic acid; And / or, The edge coating process and the surface coating process are performed in the same reaction chamber.

13. The method for preparing a perovskite-silicon tandem solar cell according to any one of claims 9-12, characterized in that, The perovskite top solar cell includes a composite layer, a first transport layer, a perovskite layer, a second transport layer, and a transparent conductive layer stacked sequentially. One of the first and second transport layers is a nickel oxide hole transport layer, and the other is an electron transport layer. The first direction is the thickness direction of the silicon bottom solar cell. After the hydrogen treatment, the second hydrogen enrichment layer includes a third sublayer formed on the exposed side surface of the nickel oxide hole transport layer; The second transport layer is an electron transport layer, and a tin oxide buffer layer is further disposed between the electron transport layer and the transparent conductive layer. The second hydrogen enrichment layer includes a fourth sub-layer formed on the exposed side surface of the tin oxide buffer layer. And / or, The perovskite top cell also includes a first electrode disposed on the transparent conductive layer, and the hydrogen treatment is performed before or after the preparation of the first electrode.

14. A photovoltaic module, characterized in that, This includes solar cells as described in any one of claims 1-8 or solar cells prepared by the method described in any one of claims 9-13.

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