Intrinsic passivation layer of solar cells and its preparation method, solar cells, photovoltaic modules

Abstract

This application relates to the field of solar cells, disclosing an intrinsic passivation layer for a solar cell, its fabrication method, a solar cell, and a photovoltaic module. The intrinsic passivation layer includes: a first passivation sublayer; a barrier layer comprising a first surface and a second surface disposed opposite to each other, the first surface being in contact with the surface of the first passivation sublayer, the structure factor of the barrier layer being 2%~5%; and a second passivation sublayer disposed on the second surface of the barrier layer, the second passivation sublayer being the main passivation layer; wherein the second surface of the barrier layer is a surface treated with plasma cleaning. The intrinsic passivation layer of this application has a higher passivation effect, which is more conducive to improving the photoelectric conversion efficiency of the solar cell.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to an intrinsic passivation layer for a solar cell and its preparation method, a solar cell, and a photovoltaic module. Background Technology

[0002] When preparing a second passivation sublayer on the first passivation sublayer of a solar cell, the interface cleanliness of the first passivation sublayer will affect its interfacial bonding effect with the second passivation sublayer.

[0003] While plasma cleaning can improve the surface cleanliness of the first passivation sublayer, it can also negatively impact the film, affecting the passivation effect of the intrinsic passivation layer and consequently the photoelectric conversion efficiency of the solar cell. Summary of the Invention

[0004] This application discloses an intrinsic passivation layer for a solar cell, its fabrication method, a solar cell, and a photovoltaic module. The intrinsic passivation layer of this application has a higher passivation effect, which is more conducive to improving the photoelectric conversion efficiency of the solar cell.

[0005] In a first aspect, this application discloses an intrinsic passivation layer for a solar cell, the intrinsic passivation layer comprising: First passivation sublayer; A barrier layer, comprising a first surface and a second surface disposed opposite to each other, wherein the first surface is in contact with the surface of the first passivation sublayer, and the structure factor of the barrier layer is 2% to 5%; The second passivation sublayer is disposed on the second surface of the barrier layer, and the second passivation sublayer is the main passivation layer; The second surface of the barrier layer is a surface that has undergone plasma cleaning treatment.

[0006] Furthermore, the thickness of the barrier layer is 1.2 nm to 1.5 nm.

[0007] Furthermore, the passivation layer satisfies at least one of the following conditions: (1) The ratio of the thickness of the first passivation sublayer to the thickness of the barrier layer is 1:2.4 to 1:15; (2) The refractive index of the barrier layer is 6.0~6.5; (3) The contact resistivity between the second passivation sublayer and the barrier layer is 10 Ω·cm. 2 ~15 Ω·cm 2 ; (4) The refractive index of the first passivation sublayer is 4.2~4.5; (5) The extinction coefficient of the first passivation sublayer is 0.04~0.06; (6) The structure factor of the first passivation sublayer is 15%~18%; (7) The thickness of the first passivation sublayer is 0.1 nm to 0.5 nm; (8) The thickness of the second passivation sublayer is 1.8 nm to 2.5 nm.

[0008] Furthermore, the passivation layer also includes a third passivation sub-layer, which is disposed on the side surface of the first passivation sub-layer facing away from the barrier layer; The passivation layer further includes a fourth passivation sublayer disposed on the side of the second passivation sublayer facing away from the barrier layer.

[0009] Secondly, this application discloses a method for preparing an intrinsic passivation layer for a solar cell, the method comprising the following steps: A barrier layer is prepared on a first passivation sublayer. The barrier layer includes a first surface and a second surface disposed opposite to each other. The first surface is in contact with the surface of the first passivation sublayer. The structure factor of the barrier layer is 2% to 5%. The second surface of the barrier layer is subjected to plasma cleaning treatment; A second passivation sublayer is prepared on the second surface; Post-processing is performed to obtain the intrinsic passivation layer.

[0010] Furthermore, in the step of preparing the barrier layer on the first passivation sublayer, the reaction gas source is silane, the flow rate is 500 sccm~1000 sccm, the power is 200 W~400 W, and the pressure is 0.1 Torr~0.12 Torr.

[0011] Furthermore, in the step of performing plasma cleaning treatment on the second surface of the barrier layer, inert gas and hydrogen are used for the plasma cleaning treatment.

[0012] Furthermore, the flow rate ratio of the inert gas to hydrogen is 1:1 to 1:2.5; and / or, The inert gas includes at least one of argon and helium; and / or, In the plasma cleaning process, the pressure is 1.4 Torr to 1.6 Torr, the ignition power is 100 W to 2000 W, and the time is 10 s to 20 s.

[0013] Further, in the step of preparing the second passivation sublayer on the second surface, the flow rate ratio of silane to hydrogen in the reaction gas source is 1:0.5 to 1:4, the power is 500 W to 8400 W, and the pressure is 0.5 Torr to 0.75 Torr; and / or, The post-processing steps include: preparing a fourth passivation sublayer on the second passivation sublayer; and / or, Before the step of preparing a barrier layer on the first passivation sublayer, the preparation method further includes: preparing a third passivation sublayer on a substrate, and preparing the first passivation sublayer on the third passivation sublayer.

[0014] Thirdly, this application discloses a solar cell, which includes an intrinsic passivation layer as described in any one of the first aspects, or an intrinsic passivation layer prepared by the preparation method described in any one of the second aspects.

[0015] Furthermore, the solar cell is a heterojunction solar cell, which includes: a substrate, and the intrinsic passivation layer, the doped silicon layer, the transparent conductive layer, and the electrode sequentially stacked on at least one surface of the substrate; The first passivation sublayer of the intrinsic passivation layer is disposed on the surface of the substrate.

[0016] Fourthly, this application discloses a photovoltaic module, which includes: the solar cell described in any one of the third aspects.

[0017] Compared with the prior art, the beneficial effects of this application are as follows: This application provides an intrinsic passivation layer for a solar cell, a method for preparing the same, a solar cell, and a photovoltaic module. The intrinsic passivation layer of this application has a higher passivation effect and is more conducive to improving the photoelectric conversion efficiency of the solar cell.

[0018] The second surface of the barrier layer in this application is the surface after plasma cleaning with process gas. The surface cleanliness of the second surface after plasma cleaning is high, resulting in a high interfacial bonding performance between the barrier layer and the second passivation sublayer. Simultaneously, the barrier layer in this application is disposed on the first passivation sublayer, and the structure factor of this barrier layer is 2% to 5%. Controlling the structure factor of the barrier layer within this specific range ensures, on the one hand, that the barrier layer has high structural density, effectively blocking ions generated during plasma cleaning from entering the first passivation sublayer, thereby effectively reducing etching caused by ion entry and ensuring a more complete film structure in the first passivation sublayer. On the other hand, controlling the structure factor within the aforementioned range largely avoids excessively high crystallinity due to an excessively small structure factor, thus fully preserving the excellent passivation performance achieved by the intrinsic passivation layer through its microcrystalline or amorphous structure. Thus, this application effectively improves the passivation effect of the intrinsic passivation layer through the two aforementioned effects of the barrier layer with a specific structure factor range. Attached Figure Description

[0019] 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.

[0020] Figure 1 This is a schematic diagram of the structure of an intrinsic passivation layer provided in an embodiment of this application; Figure 2 This is a schematic diagram of another intrinsic passivation layer structure provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of the first type of solar cell provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of the second type of solar cell provided in the embodiments of this application; Figure 5 This is a schematic diagram of the structure of the third type of solar cell provided in the embodiments of this application.

[0021] Icons: 1. Intrinsic passivation layer; 11. First passivation sublayer; 12. Barrier layer; 121. First surface; 122. Second surface; 13. Second passivation sublayer; 14. Third passivation sublayer; 15. Fourth passivation sublayer; 2. Substrate; 21. Light-receiving surface; 22. Backlight-receiving surface; 3. Doped silicon layer; 31. First doped layer; 32. Second doped layer; 4. Transparent conductive layer; 5. Electrode; 6. Intrinsic silicon passivation layer. Detailed Implementation

[0022] 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.

[0023] 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.

[0024] 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.

[0025] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (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, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0026] The technical solutions provided in this application will be further described below with reference to the embodiments and accompanying drawings.

[0027] When preparing a second passivation sublayer on the first passivation sublayer of a solar cell, the surface cleanliness of the first passivation sublayer after treatment with plasma cleaning process is high, resulting in good interfacial bonding with the second passivation sublayer and fewer interfacial defects, which can effectively reduce the recombination rate of charge carriers.

[0028] However, the applicant discovered that ions such as hydrogen ions generated during plasma cleaning migrate into the first passivation sublayer, thereby etching the first passivation sublayer, resulting in poor film integrity, more internal defects, and thus difficulty in effectively exerting its passivation performance.

[0029] Based on the above problems, this application discloses an intrinsic passivation layer for a solar cell and its preparation method, a solar cell, and a photovoltaic module. The intrinsic passivation layer of this application has a higher passivation effect and is more conducive to improving the photoelectric conversion efficiency of the solar cell.

[0030] This application discloses an intrinsic passivation layer 1 for a solar cell, such as... Figure 1 As shown, the intrinsic passivation layer 1 includes: First passivation sublayer 11; Barrier layer 12 includes a first surface 121 and a second surface 122 disposed opposite to each other. The first surface 121 is in contact with the surface of the first passivation sublayer 11. The structure factor of barrier layer 12 is 2% to 5%. The second passivation sub-layer 13 is disposed on the second surface 122 of the barrier layer 12, and the second passivation sub-layer 13 is the main passivation layer; The second surface 122 of the barrier layer 12 is a surface that has been treated with plasma cleaning.

[0031] In this context, the second passivation sublayer 13 being the primary passivation layer means that it is the film layer in the intrinsic passivation layer 1 that bears the main hydrogen passivation capability and contributes the most to the overall hydrogen passivation capability of the intrinsic passivation layer 1. Additionally, the first passivation sublayer 11 can, for example, be an anti-yellowing powder layer. The primary function of the anti-yellowing powder layer is to prevent powder shedding; its passivation function is secondary, and its passivation capability is weaker than that of the second passivation sublayer 13.

[0032] The second surface 122 of the barrier layer 12 in this application is the surface after plasma cleaning treatment with process gas. The surface cleanliness of the second surface 122 after plasma cleaning treatment is high. The high cleanliness makes the barrier layer 12 and the second passivation sublayer 13 have high interfacial bonding performance, fewer interface defects, and more conducive to reducing the recombination loss of charge carriers at the interface.

[0033] Furthermore, the structure factor of this application was measured using a Bruker ALPHA II Fourier transform infrared spectrometer. This application does not limit the specific testing method, as long as it achieves the purpose of this application.

[0034] Meanwhile, the applicant's research found that the smaller the structure factor of the barrier layer 12, the higher the compactness of the film layer, and the higher the compactness, the better it helps to block the diffusion of ions generated during plasma cleaning to the first passivation sublayer 11. However, if the structure factor is too small, it will lead to an increase in the crystallinity of the barrier layer 12. The increase in crystallinity will weaken the microcrystalline or amorphous structural characteristics on which the intrinsic passivation layer 1 depends for passivation, thereby leading to a decrease in the passivation effect of the intrinsic passivation layer 1.

[0035] Therefore, this application controls the structure factor of the barrier layer 12 within a specific range. On the one hand, this ensures that the barrier layer 12 has high density, effectively preventing ions generated during plasma cleaning from diffusing into the first passivation sublayer 11, thereby reducing the etching damage to the first passivation sublayer 11 and ensuring the structural integrity of the first passivation sublayer 11 to a high extent, thus effectively ensuring the performance of the first passivation sublayer 11. On the other hand, this structure factor range avoids excessively high crystallinity due to an excessively small structure factor, allowing the barrier layer 12 to maintain microcrystalline or amorphous properties, which further helps to improve the passivation effect of the intrinsic passivation layer 1. For example, the structure factor of the barrier layer 12 is 2%, 2.8%, 3.5%, 4.2%, or 5%, etc.

[0036] In summary, the above-mentioned configuration of this application, while ensuring a high bonding ability between the barrier layer 12 and the second passivation sub-layer 13, can reduce the etching effect of ions on the first passivation sub-layer 11, effectively ensuring the structural integrity of the first passivation sub-layer 11, and can also control the crystal content in the intrinsic passivation layer 1, thereby further improving the passivation effect of the intrinsic passivation layer 1.

[0037] Furthermore, the thickness of the barrier layer 12 is 1.2 nm to 1.5 nm. By setting the thickness of the barrier layer 12 within the above range, the barrier layer 12's blocking ability can be effectively ensured, thereby more effectively preventing ions generated during plasma cleaning from entering the first passivation sublayer 11, which in turn helps to ensure the integrity of the first passivation sublayer 11. Moreover, the aforementioned thickness can also effectively control the stress accumulation of the barrier layer 12, thereby preventing excessive stress accumulation from causing a decrease in the interfacial bonding force between the barrier layer 12 and the first passivation sublayer 11, and between the barrier layer 12 and the second passivation sublayer 13, thus effectively ensuring the interfacial bonding capability of the multilayer film structure. For example, the thickness of the barrier layer 12 is 1.2 nm, 1.28 nm, 1.36 nm, 1.42 nm, or 1.5 nm, etc.

[0038] In addition, the thickness refers to the average thickness. Taking the thickness of the barrier layer 12 as an example, it is a value obtained by calculating the thickness values ​​of the barrier layer 12 measured at multiple locations. It reflects the overall thickness level of the barrier layer 12 in the thickness direction.

[0039] Furthermore, when using an ellipsometer to test the thickness of the barrier layer 12, at least five points are taken on the barrier layer 12, and the thickness values ​​at these five points are measured respectively to obtain the average value of the measurement data. For example, an ellipsometer manufactured by Sentch GmbH, Germany, model SE-800, can be used to test the film thickness. This application does not limit the specific testing method, as long as it achieves the purpose of this application.

[0040] Furthermore, the intrinsic passivation layer 1 of this application has an additional barrier layer 12 compared to existing methods. This additional barrier layer 12 negatively impacts the conductivity and light transmittance of the intrinsic passivation layer 1. Therefore, this application can control the ratio of the thickness of the first passivation sub-layer 11 to the thickness of the barrier layer 12 to be 1:2.4 to 1:15. This allows for the synergistic optimization of the overall light transmittance and conductivity of the intrinsic passivation layer 1 while maintaining the passivation effect, thereby improving the photoelectric conversion efficiency of the solar cell. For example, the thickness ratio can be 1:2.4, 1:5, 1:9, 1:10, or 1:15.

[0041] Furthermore, the refractive index of the barrier layer 12 is 6.0 to 6.5. By controlling the refractive index of the barrier layer 12 within the above range, the absorption capacity of sunlight can be effectively improved, thereby further contributing to improving the photoelectric conversion efficiency of the solar cell. For example, the refractive index is 6.0, 6.1, 6.2, 6.3, or 6.5, etc.

[0042] Furthermore, the arrangement of the barrier layer 12 in this application ensures good interfacial bonding between the second passivation sublayer 13 and the barrier layer 12, thereby reducing the contact resistivity between the second passivation sublayer 13 and the barrier layer 12 from 20 Ω·cm. 2 ~30Ω·cm 2 Reduced to 10 Ω·cm 2 ~15 Ω·cm 2 This helps to significantly reduce carrier transport losses at the contact interface, thereby further improving the photoelectric conversion efficiency of the solar cell. For example, the contact resistivity is 10 Ω·cm. 2 11 Ω·cm 2 12 Ω·cm 2 13 Ω·cm 2 Or 15 Ω·cm 2 wait.

[0043] The contact resistivity was measured using a Keysight B2901A TLM tester. This application does not limit the specific testing method; any method that achieves the desired effect is acceptable.

[0044] Furthermore, the design of the barrier layer 12 in this application results in higher film performance for the first passivation sublayer 11, thereby increasing the refractive index of the first passivation sublayer 11 from 3.6~4.0 to 4.2~4.5. This effectively improves the absorption capacity of sunlight, thus further enhancing the photoelectric conversion efficiency of the solar cell. For example, the refractive index may be 4.2, 4.28, 4.32, 4.41, or 4.5.

[0045] Furthermore, the design of the barrier layer 12 in this application results in higher film performance for the first passivation sublayer 11, thereby reducing the extinction coefficient of the first passivation sublayer 11 from 0.07~0.09 to 0.04~0.06. An extinction coefficient of 0.04~0.06 for the first passivation sublayer 11 further enhances the absorption of sunlight and improves the photoelectric conversion efficiency of the solar cell. For example, the extinction coefficient can be 0.04, 0.045, 0.05, 0.055, or 0.06.

[0046] The refractive index and extinction coefficient can be measured using an ellipsometer (model SE-800) manufactured by Sentch GmbH, Germany. This application does not limit the specific testing method; any method that achieves the desired effect is acceptable.

[0047] Furthermore, the design of the barrier layer 12 in this application results in a lower degree of corrosion of the first passivation sublayer 11 and a higher integrity of the film layer. Therefore, the structure factor of the first passivation sublayer 11 can be reduced from 20%~25% to 15%~18%, thereby better ensuring the passivation effect of the first passivation sublayer 11. For example, the structure factor can be 15%, 15.6%, 16.3%, 17.2%, or 18%, etc.

[0048] The thickness of the first passivation sublayer 11 is 0.1 nm to 0.5 nm. By controlling the thickness of the first passivation sublayer 11 within the above range, its anti-yellowing effect can be effectively improved, and the overall passivation performance of the intrinsic passivation layer 1 can be optimized to a higher extent. For example, the thickness of the first passivation sublayer 11 is 0.1 nm, 0.2 nm, 0.3 nm, 0.4 nm, or 0.5 nm, etc.

[0049] Furthermore, the thickness of the second passivation sublayer 13 is 1.8 nm to 2.5 nm. By controlling the thickness of the second passivation sublayer 13 within the above range, it is more helpful to ensure the passivation performance of the second passivation sublayer 13, thereby helping to improve the passivation performance of the intrinsic passivation layer 1 to a greater extent. For example, the thickness of the second passivation sublayer 13 is 1.8 nm, 2.0 nm, 2.2 nm, 2.4 nm, or 2.5 nm, etc.

[0050] Furthermore, such as Figure 2 As shown, the passivation layer also includes a third passivation sublayer 14, which is disposed on the side surface of the first passivation sublayer 11 facing away from the barrier layer 12. The passivation layer also includes a fourth passivation sublayer 15 disposed on the side of the second passivation sublayer 13 facing away from the barrier layer 12.

[0051] In this application, the third passivation sublayer 14 is in direct contact with the substrate, which can prevent epitaxial growth. By setting a fourth passivation sublayer 15 on the second passivation sublayer 13, the fourth passivation sublayer 15 can serve as a connecting layer between the intrinsic passivation layer 1 and other films located on the intrinsic passivation layer 1, thereby improving the interface bonding effect and increasing the photoelectric conversion efficiency of the solar cell.

[0052] Furthermore, the thickness of the third passivation sublayer 14 is 0.5 nm to 1.5 nm. By controlling the thickness of the third passivation sublayer 14 within the above range, it is more helpful to ensure the anti-epitaxial effect of the third passivation sublayer 14, thereby helping to improve the passivation performance of the intrinsic passivation layer 1 to a greater extent. For example, the thickness of the third passivation sublayer 14 is 0.5 nm, 1.0 nm, 1.36 nm, 1.42 nm, or 1.5 nm, etc.

[0053] The thickness of the fourth passivation sublayer 15 is 1.5 nm to 2.2 nm. By controlling the thickness of the fourth passivation sublayer 15 within the above range, it is more helpful to improve the interfacial bonding effect between the intrinsic passivation layer 1 and other film layers, thereby helping to improve the photoelectric conversion efficiency of the solar cell to a greater extent. For example, the thickness of the second passivation sublayer 13 is 1.5 nm, 1.6 nm, 1.7 nm, 1.9 nm, or 2.2 nm, etc.

[0054] This application discloses a method for preparing an intrinsic passivation layer for a solar cell, the method comprising the following steps: A barrier layer is prepared on the first passivation sublayer. The barrier layer includes a first surface and a second surface disposed opposite to each other. The first surface is in contact with the surface of the first passivation sublayer. The structure factor of the barrier layer is 2% to 5%. The second surface of the barrier layer is subjected to plasma cleaning treatment; A second passivation sublayer is prepared on the second surface; Post-processing yields an intrinsic passivation layer.

[0055] Furthermore, in the step of preparing the barrier layer on the first passivation sublayer, the reaction gas source is silane, with a flow rate of 500 sccm to 1000 sccm, a power of 200 W to 400 W, and a pressure of 0.1 Torr to 0.12 Torr. By controlling the preparation parameters within the above range, the quality of the first passivation sublayer is high, which helps to improve the passivation effect of the intrinsic passivation layer to a greater extent.

[0056] Furthermore, in the step of plasma cleaning the second surface of the barrier layer, inert gas and hydrogen are used for plasma cleaning. By using inert gas and hydrogen for plasma cleaning, the inert gas has a dilution effect on the hydrogen, which can effectively reduce the etching effect of hydrogen on the first passivation sublayer; in addition, the ionization energy of the inert gas is low, and the generated plasma has higher stability, which is more conducive to achieving a good cleaning effect on the barrier layer.

[0057] Furthermore, the flow rate ratio of inert gas to hydrogen is 1:1 to 1:2.5. By controlling the flow rate ratio of inert gas to hydrogen within the above range, the cleaning effect on the second surface of the barrier layer can be further ensured, and the dilution effect can be effectively achieved, reducing the degree of etching of the first passivation sublayer by hydrogen. For example, the flow rate ratio is 1:1, 1:1.4, 1:1.7, 1:2, or 1:2.5, etc.

[0058] The inert gas includes at least one of argon and helium. When this gas is used, there is no chemical reaction between it and the barrier layer or the first passivation sublayer, which helps to ensure the passivation effect of the intrinsic passivation layer to a high degree.

[0059] Furthermore, in the plasma cleaning step, the pressure is 1.4 Torr to 1.6 Torr, the ignition power is 100 W to 2000 W, and the time is 10 s to 20 s. By controlling the preparation parameters within the above range, the structure factor of the barrier layer can be kept within the above range, which can more effectively improve the passivation effect of the intrinsic passivation layer.

[0060] Furthermore, in the step of preparing the second passivation sublayer on the second surface, the flow rate ratio of silane to hydrogen in the reaction gas source is 1:0.5 to 1:4, the power is 500 W to 8400 W, and the pressure is 0.5 Torr to 0.75 Torr. By controlling the parameters for preparing the second passivation sublayer within the above range, it is easier to ensure the quality of the prepared second passivation sublayer, thereby helping to improve the passivation effect of the intrinsic passivation layer to a greater extent.

[0061] Further, the post-processing step includes preparing a fourth passivation sublayer on the second passivation sublayer. During the preparation of the fourth passivation sublayer, the reaction gas source is silane and hydrogen, with a silane to hydrogen flow rate ratio of 1:1 to 1:15, a pressure of 0.5 Torr to 1 Torr, and a power of 2000 W to 2500 W. By controlling the preparation parameters of the fourth passivation sublayer within the above range, the preparation effect of the fourth passivation sublayer can be effectively ensured, thereby further improving the passivation effect of the intrinsic passivation layer.

[0062] Furthermore, prior to the step of preparing a barrier layer on the first passivation sublayer, the preparation method further includes: preparing a third passivation sublayer on a substrate, and preparing a first passivation sublayer on the third passivation sublayer.

[0063] In the preparation of the first passivation sublayer, the reaction gas source is silane, with a flow rate of 1500 sccm~2500 sccm, a pressure of 0.3 Torr~0.45 Torr, and a power of 600 W~1000 W. By controlling the preparation parameters of the first passivation sublayer within the above range, the film quality of the first passivation sublayer can be more effectively ensured, thereby enabling it to effectively exert the anti-yellowing effect.

[0064] In addition, during the preparation of the third passivation sublayer, the reaction gas source was silane, with a flow rate of 1500 sccm to 2500 sccm, a pressure of 0.4 Torr to 0.7 Torr, and a power of 1000 W to 1500 W. By controlling the preparation parameters of the third passivation sublayer within the above range, the film quality of the third passivation sublayer can be more effectively ensured, thereby enabling it to effectively perform its anti-epitaxy effect.

[0065] This application discloses a solar cell, which includes the intrinsic passivation layer described above, or includes an intrinsic passivation layer prepared by the above-described preparation method.

[0066] Furthermore, the solar cell is a heterojunction solar cell, such as... Figures 3 to 5 As shown, the heterojunction solar cell includes: a substrate 2, and an intrinsic passivation layer 1, a doped silicon layer 3, a transparent conductive layer 4, and an electrode 5, which are sequentially stacked on at least one surface of the substrate 2. The first passivation sublayer 11 of the intrinsic passivation layer 1 is disposed on the surface of the substrate 2.

[0067] For heterojunction solar cells, the intrinsic passivation layer 1 is in direct contact with the substrate 2, which can form a heterojunction interface. The presence of the heterojunction interface helps to reduce the recombination rate of charge carriers at the interface and improve the photoelectric conversion efficiency of the solar cell.

[0068] Additionally, structures such as the blocking layer 12 can be disposed on the light-receiving surface 21 and / or the backlight surface 22 of the substrate 2. In an optional embodiment, see reference [link to previous section]. Figure 3 A barrier layer 12 and other structures are disposed on the light-receiving surface 21 of the substrate 2. At this time, an intrinsic silicon passivation layer 6 is disposed on the back surface 22 of the substrate 2. This intrinsic silicon passivation layer 6 is neither subjected to plasma cleaning nor has a barrier layer 12 been fabricated. In another optional embodiment, refer to [reference needed]. Figure 4A barrier layer 12 and other structures are disposed on the back surface 22 of the substrate 2. At this time, an intrinsic silicon passivation layer 6 is disposed on the light-receiving surface 21 of the substrate 2. This intrinsic silicon passivation layer 6 is neither subjected to plasma cleaning nor has a barrier layer 12 been fabricated. In a third optional embodiment, refer to [reference needed]. Figure 5 Structures such as the blocking layer 12 are disposed on the light-receiving surface 21 and the backlight surface 22 of the substrate 2.

[0069] It should be noted that in heterojunction solar cells, the passivation layer on the light-receiving surface 21 is thinner than the passivation layer on the back surface 22. When structures such as the blocking layer 12 are disposed on the back surface 22 of the substrate 2, their improvement on the passivation performance of the back surface 22 is more significant.

[0070] The doped silicon layer 3 further includes a first doped layer 31 and a second doped layer 32, one of which is an N-type doped layer and the other is a P-type doped layer. The thickness of the N-type doped layer is 15 nm to 25 nm. By controlling its thickness within this range, the degree of parasitic absorption can be effectively controlled, and it also helps to improve the carrier transport efficiency.

[0071] Furthermore, the gases used in preparing the N-type doped layer include silane, nitrous oxide, phosphine, and hydrogen. The process gas pressure is 4 Torr to 6 Torr, and the ignition power is 6000 W to 12000 W. The gas flow ratio of silane, nitrous oxide, phosphine, and hydrogen is 1:(0 to 8):(0 to 8):(180 to 350), and the ignition time is 100 s to 250 s.

[0072] By controlling the preparation parameters of the N-type doped layer within the above range, it is easier to ensure the preparation of a film layer with higher quality, thereby helping to improve the photoelectric conversion efficiency of solar cells to a greater extent.

[0073] In addition, the thickness of the p-type doped layer is 18 nm to 35 nm. By controlling its thickness within the above range, the degree of parasitic absorption can be effectively controlled, and it can also help improve the carrier transport efficiency.

[0074] Furthermore, the gases used in preparing the P-type doped layer include silane, nitrous oxide, a dopant source, and hydrogen. The process gas pressure is 5 Torr to 7 Torr, and the ignition power is 6000 W to 12000 W. The gas flow rate ratio of silane, nitrous oxide, dopant source, and hydrogen is 1:0.1:0.2:100 to 1:0.5:0.8:400, and the ignition time is 220 s to 360 s. The dopant source includes at least one of B₂H₆, BH₃, BCl₃, and TMB.

[0075] By controlling the preparation parameters of the P-type doped layer within the above range, it is easier to ensure the preparation of a film layer with higher quality, thereby helping to improve the photoelectric conversion efficiency of solar cells to a greater extent.

[0076] This application discloses a photovoltaic module, which includes the aforementioned solar cell.

[0077] The technical solution of this application will be further explained below with reference to more specific embodiments and experimental test results.

[0078] Example 1: This application provides a heterojunction solar cell, which includes an intrinsic passivation layer. The fabrication method of the heterojunction solar cell includes the following steps: Texturing of N-type silicon substrates.

[0079] Intrinsic passivation layers were fabricated on the back surface of a silicon substrate using PECVD. The steps for fabricating the intrinsic passivation layers included: A third passivation sublayer was prepared on an N-type silicon substrate; wherein the reaction gas was SiH4, the flow rate was 2000 sccm, the pressure was 0.5 Torr, the power was 1000 W, and the thickness of the first passivation sublayer was 1.0 nm. A first passivation sublayer was prepared on the third passivation sublayer; wherein the reaction gas was SiH4, the flow rate was 2000 sccm, the pressure was 0.35 Torr, the power was 800 W, and the thickness of the first passivation sublayer was 0.3 nm, the structure factor was 16%, the refractive index was 4.3, and the extinction coefficient was 0.05. A barrier layer is prepared on the first passivation sublayer, and the first surface of the barrier layer is in contact with the first passivation sublayer. The reaction gas is SiH4, the flow rate is 800 sccm, the ignition power is 300 W, the pressure is 0.11 Torr, and the obtained barrier layer has a thickness of 1.35 nm, a structure factor of 2.5%, and a refractive index of 6.2. The second surface of the barrier layer was plasma cleaned using argon and hydrogen; the flow ratio of Ar to H2 was 1:1.5, the process gas pressure was 1.5 Torr, the ignition power was 1000 W, and the treatment time was 15 s. A second passivation sublayer is prepared on the second surface; wherein the reactant gases are SiH4 and H2, the flow ratio of silane to hydrogen is 1:2, the pressure is 0.6 Torr, the power is 700 W, the film thickness is 2.0 nm, and the contact resistivity between the second passivation sublayer and the barrier layer is 12 Ω·cm. 2 ; A fourth passivation sublayer is prepared on the second passivation sublayer to obtain the intrinsic passivation layer; wherein the gas used is SiH4 and H2, the flow ratio is 1:12, the pressure is 0.8 Torr, the power is 2200 W, and the thickness of the obtained intrinsic passivation layer is 2.0 nm.

[0080] An intrinsic silicon passivation layer is prepared on the light-receiving surface. The process gases used include SiH4, N2O and H2. The flow rate ratio of SiH4, N2O and H2 is 1:(0~1 / 10):(0~25). The process gas pressure is 0.5 Torr~0.7 Torr. The ignition power is 200 W~2500 W. The film thickness is 10 nm.

[0081] An N-type doped layer was deposited on an intrinsic silicon passivation layer using PECVD. The process gases were SiH4, N2O, PH3, and H2, with a process gas pressure of 5 Torr and an ignition power of 10,000 W. The gas flow ratio of SiH4, N2O, PH3, and H2 was 1:1:1:200, the ignition time was 150 s, and the thickness of the resulting N-type doped layer was 20 nm.

[0082] A P-type doped layer was deposited on the intrinsic passivation layer of the light-receiving surface using PECVD. The process gases were SiH4, N2O, B2H6, and H2, with a process gas pressure of 6 Torr, an ignition power of 10000 W, a flow ratio of SiH4, N2O, B2H6, and H2 of 1:0.1:0.2:100, an ignition time of 300 s, and a film thickness of 20 nm for the obtained P-type doped layer.

[0083] Transparent conductive layers are deposited on the N-type doped layer and the P-type doped layer, respectively.

[0084] Silver electrodes are printed on a transparent conductive layer.

[0085] Example 2: The only difference between this embodiment and Embodiment 1 is that the structure factor of the barrier layer is 2%.

[0086] Example 3: The only difference between this embodiment and Embodiment 1 is that the structure factor of the barrier layer is 5%.

[0087] Example 4: The only difference between this embodiment and Embodiment 1 is that the thickness of the barrier layer is 1.2 nm and the thickness of the first passivation sublayer is 0.3 nm.

[0088] Example 5: The only difference between this embodiment and Embodiment 1 is that the thickness of the barrier layer is 1.5 nm and the thickness of the first passivation sublayer is 0.1 nm.

[0089] Example 6: The only difference between this embodiment and Embodiment 1 is that the thickness of the barrier layer is 2 nm and the thickness of the first passivation sublayer is 1.5 nm.

[0090] Example 7: The only difference between this embodiment and Embodiment 1 is that the thickness of the barrier layer is 1 nm and the thickness of the first passivation sublayer is 1 nm.

[0091] Example 8: The only difference between this embodiment and Embodiment 1 is that the flow ratio of argon to hydrogen is 1:1.

[0092] Example 9: The only difference between this embodiment and Embodiment 1 is that the flow rate ratio of argon to hydrogen is 1:2.5.

[0093] Example 10: The only difference between this embodiment and Embodiment 1 is that the flow rate ratio of argon to hydrogen is 1:0.1.

[0094] Example 11: The only difference between this embodiment and Embodiment 1 is that the flow rate ratio of argon to hydrogen is 1:3.

[0095] Comparative Example 1: The only difference between this comparative example and Example 1 is that no barrier layer was set and no plasma cleaning treatment was performed.

[0096] Comparative Example 2: The only difference between this comparative example and Example 1 is that no barrier layer was provided, and the surface of the third passivation sublayer was subjected to plasma cleaning treatment.

[0097] Comparative Example 3: The only difference between this comparative example and Example 1 is that the structure factor of the barrier layer is 1%.

[0098] Comparative Example 4: The only difference between this comparative example and Example 1 is that the structure factor of the barrier layer is 6%.

[0099] Performance testing The solar cells prepared in Examples 1 to 11 and Comparative Examples 1 to 4 were subjected to the following related tests: This application describes the performance testing of a solar cell using a GIV-60 testing machine manufactured by Zhongsen Electric Technology Co., Ltd., covering aspects such as open-circuit voltage, short-circuit current, and fill factor. The tested solar cell has a silicon wafer size of 210.6 mm × 71 mm, and the calibrated light intensity is 1000 ± 5 W / m². The experimental test results are shown in Table 1, which presents the performance test results of the solar cell.

[0100] Table 1 Performance test results of solar cells

[0101] Analysis of the data from Examples 1 to 3 and Comparative Examples 1 to 5 shows that the photoelectric conversion efficiency of Examples 1 to 3 is better than that of Comparative Examples 1 to 4. It is evident that by setting a barrier layer with a structure factor of 2% to 5% and cleaning the second surface of the barrier layer, while ensuring a high bonding capacity between the barrier layer and the second passivation sublayer, the etching effect of ions on the first passivation sublayer can be reduced, and the crystal content in the intrinsic passivation layer can be controlled, thereby further improving the passivation effect of the intrinsic passivation layer.

[0102] Analysis of the data from Examples 1, 4 to 7 shows that the photoelectric conversion efficiency of Examples 1, 4, and 5 is better than that of Examples 6 and 7. This indicates that the thickness matching between the barrier layer and the first passivation sublayer is higher in Examples 1, 4, and 5, thus contributing more to improving the photoelectric conversion efficiency of the solar cell.

[0103] Analysis of the data from Examples 1, 8 to 11 shows that the photoelectric conversion efficiency of Examples 1, 8, and 9 is better than that of Examples 10 and 11. This indicates that the argon to hydrogen flow ratio in Examples 1, 8, and 9 is more suitable. This more suitable flow ratio can effectively improve the interface cleaning effect and suppress the etching effect of hydrogen on the first passivation sublayer to a greater extent.

[0104] The intrinsic passivation layer of the solar cell and its preparation method, as well as the solar cell 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 description of the above embodiments is only for the purpose of helping to understand the intrinsic passivation layer of the solar cell and its preparation method, as well as the solar cell and photovoltaic module. 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. An intrinsic passivation layer for a solar cell, characterized in that, The intrinsic passivation layer includes: First passivation sublayer; A barrier layer, comprising a first surface and a second surface disposed opposite to each other, wherein the first surface is in contact with the surface of the first passivation sublayer, and the structure factor of the barrier layer is 2% to 5%; The second passivation sublayer is disposed on the second surface of the barrier layer, and the second passivation sublayer is the main passivation layer; The second surface of the barrier layer is a surface that has undergone plasma cleaning treatment.

2. The intrinsic passivation layer according to claim 1, characterized in that, The thickness of the barrier layer is 1.2 nm to 1.5 nm.

3. The intrinsic passivation layer according to claim 1, characterized in that, The passivation layer must satisfy at least one of the following conditions: (1) The ratio of the thickness of the first passivation sublayer to the thickness of the barrier layer is 1:2.4 to 1:15; (2) The refractive index of the barrier layer is 6.0~6.5; (3) The contact resistivity between the second passivation sublayer and the barrier layer is 10 Ω·cm. 2 ~15 Ω·cm 2 ; (4) The refractive index of the first passivation sublayer is 4.2~4.5; (5) The extinction coefficient of the first passivation sublayer is 0.04~0.06; (6) The structure factor of the first passivation sublayer is 15%~18%; (7) The thickness of the first passivation sublayer is 0.1 nm to 0.5 nm; (8) The thickness of the second passivation sublayer is 1.8 nm to 2.5 nm.

4. The intrinsic passivation layer according to claim 1, characterized in that, The passivation layer further includes a third passivation sublayer, which is disposed on the side surface of the first passivation sublayer facing away from the barrier layer; The passivation layer further includes a fourth passivation sublayer disposed on the side of the second passivation sublayer facing away from the barrier layer.

5. A method for preparing an intrinsic passivation layer for a solar cell, characterized in that, The preparation method includes the following steps: A barrier layer is prepared on a first passivation sublayer. The barrier layer includes a first surface and a second surface disposed opposite to each other. The first surface is in contact with the surface of the first passivation sublayer. The structure factor of the barrier layer is 2% to 5%. The second surface of the barrier layer is subjected to plasma cleaning treatment; A second passivation sublayer is prepared on the second surface; Post-processing is performed to obtain the intrinsic passivation layer.

6. The preparation method according to claim 5, characterized in that, In the step of preparing the barrier layer on the first passivation sublayer, the reaction gas source is silane, the flow rate is 500 sccm~1000 sccm, the power is 200 W~400 W, and the pressure is 0.1 Torr~0.12 Torr.

7. The preparation method according to claim 5, characterized in that, In the step of performing plasma cleaning treatment on the second surface of the barrier layer, inert gas and hydrogen are used for the plasma cleaning treatment.

8. The preparation method according to claim 6, characterized in that, The flow rate ratio of the inert gas to hydrogen is 1:1 to 1:2.5; and / or, The inert gas includes at least one of argon and helium; and / or, In the plasma cleaning process, the pressure is 1.4 Torr to 1.6 Torr, the ignition power is 100 W to 2000 W, and the time is 10 s to 20 s.

9. The preparation method according to claim 5, characterized in that, In the step of preparing the second passivation sublayer on the second surface, the flow rate ratio of silane to hydrogen in the reaction gas source is 1:0.5 to 1:4, the power is 500 W to 8400 W, and the pressure is 0.5 Torr to 0.75 Torr. And / or, The post-processing steps include: preparing a fourth passivation sublayer on the second passivation sublayer; and / or, Before the step of preparing a barrier layer on the first passivation sublayer, the preparation method further includes: preparing a third passivation sublayer on a substrate, and preparing the first passivation sublayer on the third passivation sublayer.

10. A solar cell, characterized in that, The solar cell includes the intrinsic passivation layer as described in any one of claims 1 to 4, or includes the intrinsic passivation layer prepared by the preparation method described in any one of claims 5 to 9.

11. The solar cell according to claim 10, characterized in that, The solar cell is a heterojunction solar cell, which includes: a substrate, and an intrinsic passivation layer, a doped silicon layer, a transparent conductive layer, and an electrode sequentially stacked on at least one surface of the substrate. The first passivation sublayer of the intrinsic passivation layer is disposed on the surface of the substrate.

12. A photovoltaic module, characterized in that, The photovoltaic module includes: the solar cell according to any one of claims 10 to 11.

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