Solar cell, method of manufacturing the same, and photovoltaic module
By setting an isolation structure between the tunneling layer and the first doped layer, the problem of reduced passivation effect of the tunneling oxide layer caused by the diffusion of doped ions during the annealing process is solved, thereby improving the performance and competitiveness of solar cells.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TRINA SOLAR CO LTD
- Filing Date
- 2024-09-18
- Publication Date
- 2026-05-22
AI Technical Summary
In the annealing process, the diffusion of dopant ions in the polycrystalline silicon layer leads to a decrease in the passivation effect of the tunnel oxide layer, which affects the performance of solar cells.
An isolation structure is provided between the tunneling layer and the first doped layer. The isolation structure consists of alternating layers of silicon oxide and doped buffer layers. The doping concentration of the doped buffer layer is lower than that of the first doped layer, which blocks the diffusion of doped ions and reduces the impact on the passivation effect of the tunneling layer.
It improves the open-circuit voltage and fill factor of solar cells, expands the process window of annealing, enhances the product competitiveness of solar cells, and reduces the impact of annealing on passivation performance.
Smart Images
Figure CN119153550B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of solar cell technology, and in particular to a solar cell, a method for preparing the same, and a photovoltaic module. Background Technology
[0002] The core structure of TOPCon (Tunnel Oxide Passivated Contact) solar cells consists of a tunnel oxide layer and a doped polycrystalline silicon layer on the surface of the tunnel oxide layer. The tunnel oxide layer can provide a high-quality chemical passivation effect to passivate defects on the substrate surface. During the annealing process, dopants in the doped polycrystalline silicon layer diffuse toward the substrate. Excessive diffusion can lead to strong Auger recombination, reducing the passivation effect of the tunnel oxide layer and affecting the performance of the solar cell. Summary of the Invention
[0003] The embodiments of this disclosure provide a solar cell, a method for preparing the same, and a photovoltaic module, which can reduce the impact of the annealing process on the passivation effect and improve the performance and competitiveness of the solar cell.
[0004] A solar cell, comprising:
[0005] Base;
[0006] A tunneling layer located on the surface of the substrate;
[0007] An isolation structure is located on the surface of the tunneling layer away from the substrate, the isolation structure comprising alternating layers of silicon oxide and doped buffer layers along a first direction perpendicular to the substrate;
[0008] The first doped layer is located on the surface of the isolation structure away from the substrate;
[0009] Wherein, the doping concentration of the first doped layer is greater than the doping concentration of the doped buffer layer.
[0010] In one embodiment, the top layer of the isolation structure away from the substrate is a doped buffer layer.
[0011] In one embodiment, the doped buffer layer includes one of an intrinsic layer and a second doped layer; or the buffer layer includes an intrinsic layer and a second doped layer stacked along the first direction.
[0012] The second doped layer and the first doped layer have the same conductivity type, and the doping concentration of the second doped layer is less than that of the first doped layer.
[0013] In one embodiment, the bottom layer of the isolation structure near the substrate is a doped buffer layer that includes at least a second doped layer adjacent to the surface of the tunneling layer away from the substrate.
[0014] In one embodiment, the material of the silicon oxide layer includes silicon dioxide.
[0015] A method for preparing a solar cell, comprising:
[0016] Provide a base;
[0017] A tunneling layer is formed on the surface of the substrate;
[0018] An isolation structure is formed on the surface of the tunneling layer away from the substrate, the isolation structure comprising alternating layers of silicon oxide and doped buffer layers along a first direction perpendicular to the substrate;
[0019] A first doped layer is formed on the surface of the isolation structure away from the substrate;
[0020] Wherein, the doping concentration of the first doped layer is greater than the doping concentration of the doped buffer layer.
[0021] In one embodiment, the step of forming a first doped layer on the surface of the isolation structure away from the substrate includes:
[0022] The first doped layer is formed on the surface of the doped buffer layer on the top layer of the isolation structure.
[0023] In one embodiment, the doped buffer layer includes one of an intrinsic layer and a second doped layer; or the buffer layer includes an intrinsic layer and a second doped layer stacked along the first direction.
[0024] The second doped layer and the first doped layer have the same conductivity type, and the doping concentration of the second doped layer is less than that of the first doped layer.
[0025] In one embodiment, forming an isolation structure on the surface of the tunneling layer away from the substrate includes:
[0026] A second doped layer is formed on the surface of the tunneling layer away from the substrate, adjacent to the tunneling layer;
[0027] The bottom layer of the isolation structure is a doped buffer layer that includes at least the second doped layer adjacent to the tunneling layer.
[0028] A photovoltaic module includes a plurality of solar cells as described above, and / or a plurality of solar cells made using the solar cell preparation method described above.
[0029] In the aforementioned solar cell, an isolation structure is provided between the first doped layer and the tunneling layer. The doping concentration of the doping buffer layer in the isolation structure is lower than that of the first doped layer, allowing dopant ions in the first doped layer to diffuse into the doping buffer layer before diffusing into the tunneling layer. Furthermore, the silicon oxide layer in the isolation structure can block the diffusion of dopant ions in the first doped layer into the tunneling layer and the substrate, thus avoiding the impact on the passivation effect of the tunneling layer, reducing the influence of internal diffusion, improving the open-circuit voltage and fill factor of the solar cell, increasing the product competitiveness of the solar cell, expanding the process window for annealing to activate dopant ions in the first doped layer, and reducing the impact of annealing process matching on the passivation performance of the solar cell.
[0030] In the above-mentioned method for fabricating solar cells, an isolation structure is formed between the first doped layer and the tunneling layer. The doping concentration of the doping buffer layer in the isolation structure is lower than that of the first doped layer, so that the dopant ions in the first doped layer diffuse into the doping buffer layer before diffusing into the tunneling layer. Furthermore, the silicon oxide layer in the isolation structure can block the diffusion of dopant ions in the first doped layer into the tunneling layer and the substrate, thus avoiding the impact on the passivation effect of the tunneling layer, reducing the impact of internal diffusion, improving the open-circuit voltage and fill factor of the solar cell, increasing the product competitiveness of the solar cell, expanding the process window of the annealing process for activating the dopant ions in the first doped layer, and reducing the impact of annealing process matching on the passivation performance of the solar cell. Attached Figure Description
[0031] To more clearly illustrate the technical solutions in the embodiments or related technologies of this disclosure, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 This is a schematic flowchart of the solar cell fabrication method in some embodiments;
[0033] Figure 2 This is a schematic cross-sectional view of the solar cell after the formation of the first doped layer in some embodiments;
[0034] Figure 3 This is a schematic cross-sectional view of the solar cell after the formation of the first doped layer in some embodiments;
[0035] Figure 4 This is a cross-sectional schematic diagram of a solar cell after the formation of the first doped layer in some other embodiments.
[0036] Explanation of reference numerals in the attached figures:
[0037] The substrate is 102, the isolation structure is 104, the first doped layer is 106, the tunneling layer is 108, the silicon oxide layer is 202, the doped buffer layer is 204, the second doped layer is 302, and the intrinsic layer is 304. Detailed Implementation
[0038] To facilitate understanding of the embodiments of this disclosure, a more complete description of the embodiments of this disclosure will be provided below with reference to the accompanying drawings. Preferred embodiments of the embodiments of this disclosure are shown in the drawings. However, the embodiments of this disclosure can be implemented in many different forms and are not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of this disclosure belong. The terminology used herein in the description of embodiments of this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments of this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0040] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, parts, regions, layers, doping types, and / or portions, these elements, parts, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, part, region, layer, doping type, or portion from another element, part, region, layer, doping type, or portion. Therefore, without departing from the teachings of this invention, the first element, component, region, layer, doping type, or portion discussed below may be represented as a second element, component, region, layer, or portion; for example, the first doping type may be referred to as the second doping type, and similarly, the second doping type may be referred to as the first doping type; the first doping type and the second doping type are different doping types, for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.
[0041] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.
[0042] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that when the terms “comprise” and / or “comprising” are used in this specification, the presence of the stated feature, integer, step, operation, element, and / or part is established, but the presence or addition of one or more other features, integers, steps, operations, elements, parts, and / or groups is not excluded. Meanwhile, when used herein, the term “and / or” includes any and all combinations of the associated listed items.
[0043] Embodiments of the invention are described herein with reference to cross-sectional views illustrating ideal embodiments (and intermediate structures) of the invention, thus allowing for variations in the illustrated shape due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the invention should not be limited to the specific shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing techniques. For instance, implantation regions shown as rectangular typically have rounded or curved features at their edges and / or implantation concentration gradients, rather than a binary change from implantation regions to non-implantation regions. Similarly, the buried regions formed by implantation can result in some implantation in the region between the buried region and the surface traversed during implantation. Therefore, the regions shown in the figures are substantially schematic, and their shapes do not represent the actual shapes of regions of the device and do not limit the scope of the invention.
[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified. In the description of this disclosure, "several" means at least one, such as one, two, etc., unless otherwise expressly specified.
[0045] Figure 1 This is a schematic flowchart illustrating the fabrication method of solar cells in some embodiments, such as... Figure 1 As shown, in this embodiment, a method for preparing a solar cell is provided, comprising:
[0046] S102 provides the substrate.
[0047] A substrate for fabricating solar cells is provided. This substrate is a doped substrate containing doped ions that can provide charge carriers. The material of the doped substrate includes a doped semiconductor substrate made of silicon or germanium, or a doped compound semiconductor substrate made of silicon carbide, silicon-germanium, gallium arsenide, indium phosphide, zinc oxide, or gallium oxide. As an example, in this embodiment, the substrate is made of doped single-crystal silicon.
[0048] S104, a tunneling layer is formed on the surface of the substrate.
[0049] Specifically, a tunneling layer is formed on the surface of the substrate, and the surface of the substrate is passivated by the tunneling layer.
[0050] S106, an isolation structure comprising alternating layers of silicon oxide and doped buffer layers is formed on the surface of the tunneling layer away from the substrate.
[0051] Specifically, an isolation structure is deposited on the surface of the tunneling layer away from the substrate. The isolation structure includes silicon oxide layers and doped buffer layers alternately stacked along a first direction perpendicular to the substrate. The silicon oxide layers have an isolation function, which can block the diffusion of ions from one side of the silicon oxide layer to the other side under heating, thus reducing the diffusion of ions from one side of the silicon oxide layer to the other side under heating. The doped buffer layer can act as a buffer zone for ion diffusion. Ions diffuse and remain in the doped buffer layer, reducing the diffusion of ions from one side of the doped buffer layer to the other side under heating. The isolation structure can reduce the diffusion of ions from one side of the isolation structure to the tunneling layer on the other side of the isolation structure, thus avoiding affecting the passivation effect of the tunneling layer.
[0052] By setting alternating layers of silicon oxide and doped buffer layers, the diffusion of doped ions from the first doped layer into the tunneling layer during heating is blocked, while the impact on the transport of charge carriers in the first direction of the doped buffer layer in the solar cell is reduced.
[0053] It is understandable that the bottom layer of the isolation structure near the substrate and the top layer away from the substrate can be either a silicon oxide layer or a doped buffer layer. The bottom layer of the isolation structure near the substrate and the top layer away from the substrate can be the same or different.
[0054] S108, a first doped layer is formed on the surface of the isolation structure away from the substrate.
[0055] Specifically, a first doped layer is formed on the surface of the isolation structure away from the substrate. The doping concentration of the first doped layer is greater than that of the doping buffer layer. This means that either the first doped layer contains dopant ions, or the doping buffer layer contains dopant ions, or the doping buffer layer does not contain dopant ions. If dopant ions are present in the doping buffer layer, the concentration of dopant ions in the first doped layer is greater than that in the doping buffer layer. An isolation structure exists between the first doped layer and the tunneling layer. During the annealing process of the first doped layer, the presence of this isolation structure reduces the diffusion of dopant ions from the first doped layer to the tunneling layer on the side of the isolation structure closer to the substrate. This reduces the impact of annealing process matching on the passivation performance of the solar cell and increases the process window of the annealing process.
[0056] In the above-mentioned method for fabricating solar cells, an isolation structure is formed between the first doped layer and the tunneling layer. The doping concentration of the doping buffer layer in the isolation structure is lower than that of the first doped layer, so that the dopant ions in the first doped layer diffuse into the doping buffer layer before diffusing into the tunneling layer. Furthermore, the silicon oxide layer in the isolation structure can block the diffusion of dopant ions in the first doped layer into the tunneling layer and the substrate, thus avoiding the impact on the passivation effect of the tunneling layer, reducing the impact of internal diffusion, improving the open-circuit voltage and fill factor of the solar cell, increasing the product competitiveness of the solar cell, expanding the process window of the annealing process for activating the dopant ions in the first doped layer, and reducing the impact of annealing process matching on the passivation performance of the solar cell.
[0057] Figure 2 This is a schematic cross-sectional view of the solar cell after the formation of the first doped layer in some embodiments, such as... Figure 2 As shown, an isolation structure 104 comprising alternating layers of silicon oxide layer 202 and doped buffer layer 204 is formed on the first surface of substrate 102, thereby reducing doped ions that diffuse to the tunneling layer 108 on the first surface of substrate 102 under heating conditions.
[0058] It is understood that the substrate 102 includes a light-receiving surface and a back-lighting surface disposed opposite to each other in a first direction perpendicular to the substrate 102. The light-receiving surface is the surface of the solar cell that faces the sunlight (light-facing surface), and the back-lighting surface is the surface of the solar cell that faces away from the sunlight. The first surface includes at least one of the light-receiving surface and the back-lighting surface.
[0059] For example, the first surface is a backlight surface, and the method for fabricating a solar cell further includes: forming a front surface structure on the light-receiving surface of the substrate 102, wherein the front surface structure includes a tunneling oxide layer and a polycrystalline silicon doped layer sequentially disposed from the substrate 102 toward the direction away from the substrate 102.
[0060] like Figure 2 As shown, in one embodiment, the step of forming a first doped layer 106 on the surface of the isolation structure 104 away from the substrate 102 includes: forming the first doped layer 106 on the surface of the doped buffer layer 204 on the top layer of the isolation structure 104. Compared with the top layer of the isolation structure 104 being a silicon oxide layer 202, setting the top layer of the isolation structure 104 to be a doped buffer layer 204 can avoid the problem that, when the silicon oxide layer 202 is in contact with the first doped layer 106, dopants in the first doped layer 106 diffuse through the silicon oxide layer 202 under the action of heating and a high concentration gradient, affecting the isolation effect of the silicon oxide layer 202. This improves the isolation effect of the silicon oxide layer 202 in the isolation structure 104, further reducing the impact of internal diffusion and improving the performance of the solar cell.
[0061] Figure 3 This is a schematic cross-sectional view of the solar cell after the formation of the first doped layer in some embodiments. Figure 4 This is a cross-sectional schematic diagram of the solar cell after the formation of the first doped layer in some embodiments, such as... Figure 3 , Figure 4 As shown, in one embodiment, the doped buffer layer 204 includes either a second doped layer 302 or an intrinsic layer 304; wherein the doping concentration of the second doped layer 302 is lower than the doping concentration of the first doped layer 106. A concentration difference exists between the first doped layer 106 and the second doped layer 302 and intrinsic layer 304. Dopants in the first doped layer 106 can diffuse into the doped buffer layer 204 (either the second doped layer 302 or the intrinsic layer 304), thereby reducing the dopants diffusing to the substrate 102 and reducing the impact of heating on the performance of the solar cell. Furthermore, the second doped layer 302 and the first doped layer 106 have the same conductivity type, including N-type and P-type, where N-type dopants include phosphorus and P-type dopants include boron.
[0062] like Figure 4As shown, in one embodiment, the buffer layer 204 includes a second doped layer 302 and an intrinsic layer 304 stacked along the first direction X; wherein the doping concentration of the second doped layer 302 is less than the doping concentration of the first doped layer 106. A concentration difference exists between the first doped layer 106 and the second doped layer 302 and the intrinsic layer 304 in the buffer layer 204. Doped ions in the first doped layer 106 can diffuse into the doped buffer layer 204 (the second doped layer 302 and the intrinsic layer 304), thereby reducing the doped ions diffusing to the tunneling layer 108 and the substrate 102, and reducing the impact of heating on the performance of the solar cell. Furthermore, the second doped layer 302 and the first doped layer 106 have the same conductivity type, including N-type and P-type.
[0063] It is understandable that the second doped layer 302 in the buffer layer 204 is close to the substrate 102, and the intrinsic layer 304 in the buffer layer 204 is far away from the substrate 102; or the second doped layer 302 in the buffer layer 204 is far away from the substrate 102, and the intrinsic layer 304 in the buffer layer 204 is close to the substrate 102.
[0064] Furthermore, the buffer layer 204 includes a second doped layer 302 and an intrinsic layer 304 alternately stacked along the first direction X. This reduces the impact on the transport of charge carriers in the solar cell along the first direction X while preventing doped ions in the first doped layer 106 from diffusing into the tunneling layer 108 and the substrate 102 during heating.
[0065] like Figure 3 , Figure 4 As shown, in one embodiment, an isolation structure 106 is formed on the surface of the tunneling layer 108 away from the substrate 102, including: forming a second doped layer 302 adjacent to the tunneling layer 108 on the surface of the tunneling layer 108 away from the substrate 102; wherein, the bottom layer of the isolation structure 104 near the substrate 102 is a doped buffer layer 204 including at least the second doped layer 302 adjacent to the tunneling layer 108. This arrangement facilitates carrier collection, improves the performance of the solar cell, and the isolation structure 104 reduces the impact of the annealing process on the passivation performance of the tunneling layer 108, thereby improving the performance of the solar cell.
[0066] It is understandable that when the bottom layer of the isolation structure 104 is a doped buffer layer 204 including a second doped layer 302 and an intrinsic layer 304, the second doped layer 302 is adjacent to the substrate 102, and the intrinsic layer 304 is adjacent to the surface of the second doped layer 302 away from the substrate 102.
[0067] For example, the material of the tunneling layer 108 and the silicon oxide layer 202 includes silicon dioxide; the material of the second doped layer 302 and the material of the first doped layer 304 includes doped polycrystalline silicon; and the material of the intrinsic layer 304 includes intrinsic polycrystalline silicon.
[0068] For example, along the direction away from the substrate 102, the surface of the substrate 102 is sequentially provided with a tunneling layer 108 (e.g., with a thickness of 2nm-3nm), a second doped layer 302 (e.g., with a thickness of 5nm-15nm), a silicon oxide layer 202 (e.g., with a thickness of 1nm-2nm), an intrinsic layer 304 (e.g., with a thickness of 5nm-10nm) and / or a second doped layer 302 (e.g., with a thickness of 5nm-10nm) and a first doped layer 106 (e.g., with a thickness of 50nm-80nm).
[0069] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.
[0070] This application also provides a solar cell, the parts of which are the same as or corresponding to the embodiments in the above-described method for preparing solar cells, and will not be repeated below. Figure 2 As shown, in some embodiments, the solar cell includes: a substrate 102, an isolation structure 104, a first doped layer 106, and a tunneling layer 108; the tunneling layer 108 is located on the surface of the substrate 102, and the isolation structure 104 is located on the surface of the tunneling layer 108 away from the substrate 102. The isolation structure 104 includes a silicon oxide layer 202 and a doping buffer layer 204 alternately stacked along a first direction X perpendicular to the substrate 102; the first doped layer 106 is located on the surface of the isolation structure 104 away from the substrate 102; wherein the doping concentration of the first doped layer 106 is greater than the doping concentration of the doping buffer layer 204.
[0071] By setting alternating layers of silicon oxide layer 202 and doped buffer layer 204, the diffusion of doped ions in the first doped layer 106 to the tunneling layer 108 during the heating process is blocked, while the impact on the transport of charge carriers in the solar cell in the first direction of the doped buffer layer 204 is reduced.
[0072] It is understood that the bottom layer of the isolation structure 104 near the substrate 102 and the top layer away from the substrate 102 are either the silicon oxide layer 202 or the doped buffer layer 204, and the bottom layer of the isolation structure 104 near the substrate 102 and the top layer away from the substrate 102 can be the same or different.
[0073] In the aforementioned solar cell, an isolation structure 104 is provided between the first doped layer 106 and the tunneling layer 108. The doping concentration of the doping buffer layer 204 in the isolation structure 104 is lower than that of the first doped layer 106, so that the doped ions in the first doped layer 106 diffuse into the doping buffer layer 204 before diffusing into the tunneling layer 108. Furthermore, the silicon oxide layer 202 in the isolation structure 104 can block the diffusion of the doped ions in the first doped layer 106 into the tunneling layer 108 and the substrate 102, thereby avoiding the impact on the passivation effect of the tunneling layer 108, reducing the impact of internal diffusion, improving the open-circuit voltage and fill factor of the solar cell, increasing the product competitiveness of the solar cell, expanding the process window of the annealing process for activating the doped ions in the first doped layer, and reducing the impact of annealing process matching on the passivation performance of the solar cell.
[0074] like Figure 2 As shown, in one embodiment, the top layer of the isolation structure 104 away from the substrate 102 is a doped buffer layer 204. Compared to the top layer of the isolation structure 104 being a silicon oxide layer 202, setting the top layer of the isolation structure 104 to a doped buffer layer 204 can prevent doped ions in the first doped layer 106 from penetrating the silicon oxide layer 202 under the action of heating and a high concentration gradient when the silicon oxide layer 202 is in contact with the first doped layer 106, thus affecting the isolation effect of the silicon oxide layer 202. This improves the isolation effect of the silicon oxide layer 202 in the isolation structure 104, further reducing the impact of internal diffusion and improving the performance of the solar cell.
[0075] like Figure 3 , Figure 4 As shown, in one embodiment, the doped buffer layer 204 includes one of an intrinsic layer 304 and a second doped layer 302; wherein the doping concentration of the second doped layer 302 is less than the doping concentration of the first doped layer 106. A concentration difference exists between the first doped layer 106 and the second doped layer 302, as well as the intrinsic layer 304. Doped ions in the first doped layer 106 can diffuse into the doped buffer layer 204 (either the second doped layer 302 or the intrinsic layer 304), thereby reducing the doped ions diffusing to the tunneling layer 108 and the substrate 102, and reducing the impact of heating on the performance of the solar cell. Furthermore, the second doped layer 302 and the first doped layer 106 have the same conductivity type, including N-type and P-type.
[0076] like Figure 2 As shown, in one embodiment, the buffer layer 204 includes an intrinsic layer 304 and a second doped layer 302 stacked along the first direction X; wherein the doping concentration of the second doped layer 302 is less than the doping concentration of the first doped layer 106. A concentration difference exists between the first doped layer 106 and the second doped layer 302 and the intrinsic layer 304 in the buffer layer 204. Doped ions in the first doped layer 106 can diffuse into the doped buffer layer 204 (the second doped layer 302 and the intrinsic layer 304), thereby reducing the doped ions diffusing to the tunneling layer 108 and the substrate 102, and reducing the impact of heating on the performance of the solar cell. Furthermore, the second doped layer 302 and the first doped layer 106 have the same conductivity type, including N-type and P-type.
[0077] like Figure 4 As shown, in one embodiment, the doped buffer layer 204 of the isolation structure 104 near the bottom layer of the substrate 102 includes at least a second doped layer 302 adjacent to the surface of the tunneling layer 108 away from the substrate 102. This arrangement facilitates carrier collection, improves the performance of the solar cell, and the isolation structure 104 reduces the impact of the annealing process on the passivation performance of the tunneling layer 108, thereby improving the performance of the solar cell.
[0078] It is understood that when the doped buffer layer 204 includes a second doped layer 302 and an intrinsic layer 304, the second doped layer 302 is adjacent to the substrate 102, and the intrinsic layer 304 is adjacent to the surface of the second doped layer 302 away from the substrate 102.
[0079] In one embodiment, the material of the silicon oxide layer 202 includes silicon dioxide.
[0080] This disclosure also provides a photovoltaic module, including a plurality of solar cells as described above, and / or a plurality of solar cells made using the solar cell preparation method described above.
[0081] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0082] The above-described embodiments are merely illustrative of several implementation methods of the present disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present disclosure embodiments, and these modifications and improvements all fall within the protection scope of the present disclosure embodiments.
Claims
1. A solar cell, characterized in that, include: Base; A tunneling layer is located on the surface of the substrate; An isolation structure is located on the surface of the tunneling layer away from the substrate. The isolation structure includes silicon oxide layers and doped buffer layers alternately stacked along a first direction perpendicular to the substrate. The doped buffer layer includes a second doped layer and an intrinsic layer stacked along the first direction. The bottom layer of the isolation structure near the substrate is the doped buffer layer, and the second doped layer in the doped buffer layer is adjacent to the substrate, while the intrinsic layer in the doped buffer layer is adjacent to the surface of the second doped layer away from the substrate. The first doped layer is located on the surface of the isolation structure away from the substrate; the top layer of the isolation structure away from the substrate is a doped buffer layer, and the intrinsic layer in the doped buffer layer is adjacent to the first doped layer. Wherein, the doping concentration of the first doped layer is greater than the doping concentration of the doped buffer layer; the second doped layer and the first doped layer have the same conductivity type, and the doping concentration of the second doped layer is less than the doping concentration of the first doped layer.
2. The solar cell according to claim 1, characterized in that, The tunneling layer is located on at least one of the light-receiving and back-light-receiving surfaces of the substrate; wherein the light-receiving and back-light-receiving surfaces are arranged opposite to each other in the first direction.
3. The solar cell according to claim 2, characterized in that, The tunneling layer is located on the back surface of the substrate; the solar cell further includes: A front surface structure is located on the light-receiving surface; the front surface structure includes a tunneling oxide layer and a polycrystalline silicon doped layer sequentially disposed from the substrate away from the substrate.
4. The solar cell according to claim 1, characterized in that, In the isolation structure, the second doped layer of the doped buffer layer is located away from the substrate, while the intrinsic layer is located close to the substrate.
5. The solar cell according to claim 1, characterized in that, The material of the silicon oxide layer includes silicon dioxide.
6. A method for preparing a solar cell, characterized in that, include: Provide a base; A tunneling layer is formed on the surface of the substrate; An isolation structure is formed on the surface of the tunneling layer away from the substrate, the isolation structure comprising alternating layers of silicon oxide and doped buffer layers along a first direction perpendicular to the substrate; A first doped layer is formed on the surface of the isolation structure away from the substrate; The doped buffer layer includes a second doped layer and an intrinsic layer stacked along the first direction; the doping concentration of the first doped layer is greater than the doping concentration of the doped buffer layer; the second doped layer and the first doped layer have the same conductivity type, and the doping concentration of the second doped layer is less than the doping concentration of the first doped layer. The formation of an isolation structure on the surface of the tunneling layer away from the substrate includes: A second doped layer is formed on the surface of the tunneling layer away from the substrate, adjacent to the tunneling layer; An intrinsic layer adjacent to the second doped layer is formed on the surface of the second doped layer away from the substrate; The step of forming a first doped layer on the surface of the isolation structure away from the substrate includes: The first doped layer is formed on the surface of the intrinsic layer in the doped buffer layer at the top of the isolation structure.
7. The method for preparing a solar cell according to claim 6, characterized in that, The tunneling layer is located on at least one of the light-receiving and backlighting surfaces of the substrate; The light-receiving surface and the backlighting surface are arranged opposite each other in the first direction.
8. The method for preparing a solar cell according to claim 7, characterized in that, The tunneling layer is located on the back surface of the substrate; the method for fabricating the solar cell further includes: A front surface structure is formed on the light-receiving surface of the substrate, wherein the front surface structure includes a tunneling oxide layer and a polycrystalline silicon doped layer sequentially disposed from the substrate away from the substrate.
9. The method for preparing a solar cell according to claim 6, characterized in that, In the isolation structure, the second doped layer of the doped buffer layer is located away from the substrate, while the intrinsic layer is located close to the substrate.
10. A photovoltaic module, characterized in that, It includes several solar cells as described in any one of claims 1-5, and / or includes several solar cells made using the method for preparing solar cells as described in any one of claims 6-9.