Solar cell, preparation method thereof and photovoltaic module

Abstract

The invention discloses a solar cell, a preparation method thereof and a photovoltaic module, and relates to the technical field of solar cells. The solar cell includes: a substrate; the tunneling layer is located on the surface of the substrate; the isolation structure is located on the surface, away from the substrate, of the tunneling layer, and the isolation structure comprises silicon oxide layers and doped buffer layers which are alternately stacked in the first direction perpendicular to the substrate; the first doping layer is located on the surface of the isolation structure away from the substrate; wherein the doping concentration of the first doped layer is greater than that of the doped buffer layer. The doping ions diffused to the tunneling layer are integrally reduced, the influence of internal expansion is reduced, the open-circuit voltage and the filling factor of the solar cell are improved, the product competitiveness of the solar cell is improved, the process window of the annealing process is expanded, and the influence of the annealing process matching on the performance of the solar cell is reduced.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the technical field of solar cells, and in particular to a solar cell and a preparation method thereof, and a photovoltaic module. Background Art

[0002] The core structure of the TOPCon (Tunnel Oxide Passivated Contact) cell consists of a tunnel oxide layer and a doped polysilicon layer located on the surface of the tunnel oxide layer. The tunnel oxide layer can provide high-quality chemical passivation to passivate defects on the substrate surface. During the annealing process, the doped ions in the doped polysilicon layer will diffuse toward the substrate. Excessive diffusion will lead to strong Auger recombination, reducing the passivation effect of the tunnel layer and affecting the performance of the solar cell. Summary of the invention

[0003] The embodiments of the present disclosure provide a solar cell and a method for preparing the same, and a photovoltaic module, which can reduce the influence of the annealing process on the passivation effect and improve the performance of the solar cell and the product competitiveness.

[0004] A solar cell, comprising:

[0005] substrate;

[0006] A tunneling layer, located on the surface of the substrate;

[0007] An isolation structure, located on a surface of the tunneling layer away from the substrate, the isolation structure comprising silicon oxide layers and doped buffer layers alternately stacked along a first direction perpendicular to the substrate;

[0008] A first doping layer is located on a surface of the isolation structure away from the substrate;

[0009] Wherein, the doping concentration of the first doping layer is greater than the doping concentration of the doping 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 doping layer and the first doping layer have the same conductivity type, and the doping concentration of the second doping layer is less than the doping concentration of the first doping layer.

[0013] In one embodiment, the bottom layer of the isolation structure close to the substrate is a doped buffer layer including at least the 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] providing a substrate;

[0017] forming a tunneling layer on the surface of the substrate;

[0018] forming an isolation structure on a surface of the tunneling layer away from the substrate, the isolation structure comprising silicon oxide layers and doped buffer layers alternately stacked along a first direction perpendicular to the substrate;

[0019] forming a first doping layer on a surface of the isolation structure away from the substrate;

[0020] Wherein, the doping concentration of the first doping layer is greater than the doping concentration of the doping buffer layer.

[0021] In one embodiment, the step of forming a first doping layer on a surface of the isolation structure away from the substrate includes:

[0022] The first doping layer is formed on the surface of the doping buffer layer at 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 doping layer and the first doping layer have the same conductivity type, and the doping concentration of the second doping layer is less than the doping concentration of the first doping layer.

[0025] In one embodiment, forming an isolation structure on a surface of the tunneling layer away from the substrate includes:

[0026] forming the second doping layer adjacent to the tunneling layer on a surface of the tunneling layer away from the substrate;

[0027] Wherein, the bottom layer of the isolation structure is a doped buffer layer which at least includes the second doped layer adjacent to the tunneling layer.

[0028] A photovoltaic assembly comprises a plurality of solar cells as described above, and / or a plurality of solar cells manufactured by the method for manufacturing a solar cell as described above.

[0029] In the above solar cell, an isolation structure is arranged between the first doping layer and the tunneling layer, and the doping concentration of the doping buffer layer in the isolation structure is lower than the doping concentration of the first doping layer, so that the doping ions in the first doping layer diffuse into the doping buffer layer before diffusing into the tunneling layer, and the silicon oxide layer in the isolation structure can block the diffusion of the doping ions in the first doping layer into the tunneling layer and the substrate, thereby avoiding the influence on the passivation effect of the tunneling layer, reducing the influence of the 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 doping ions in the first doping layer, and reducing the influence of the annealing process matching on the passivation performance of the solar cell.

[0030] In the above-mentioned method for preparing the solar cell, an isolation structure is formed between the first doping layer and the tunneling layer, and the doping concentration of the doping buffer layer in the isolation structure is less than the doping concentration of the first doping layer, so that the doping ions in the first doping layer diffuse into the doping buffer layer before diffusing into the tunneling layer, and the silicon oxide layer in the isolation structure can block the diffusion of the doping ions in the first doping layer into the tunneling layer and the substrate, avoiding the influence on the passivation effect of the tunneling layer, reducing the influence of the 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 doping ions in the first doping layer, and reducing the influence of the annealing process matching on the passivation performance of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or related technologies, the drawings required for use in the embodiments or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] FIG1 is a schematic diagram of a process for preparing a solar cell in some embodiments;

[0033] FIG2 is a schematic cross-sectional view of a solar cell after a first doping layer is formed in some embodiments;

[0034] Figure 3 is a schematic cross-sectional view of a solar cell after a first doping layer is formed in some embodiments;

[0035] Figure 4 Schematic cross-sectional view of a solar cell after the first doping layer is formed in some other embodiments.

[0036] Description of reference numerals:

[0037] The substrate 102 , the isolation structure 104 , the first doped layer 106 , the tunneling layer 108 , the silicon oxide layer 202 , the doped buffer layer 204 , the second doped layer 302 , and the intrinsic layer 304 . DETAILED DESCRIPTION

[0038] In order to facilitate understanding of the embodiments of the present disclosure, the embodiments of the present disclosure will be described more fully below with reference to the relevant drawings. The preferred embodiments of the embodiments of the present disclosure are shown in the drawings. However, the embodiments of the present disclosure can be implemented in many different forms and are not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the embodiments of the present disclosure more thorough and comprehensive.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the disclosed embodiments belong. The terms used herein in the specification of the disclosed embodiments are only for the purpose of describing specific embodiments and are not intended to limit the disclosed embodiments. The term "and / or" used herein includes any and all combinations of one or more of the related 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 can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, 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. can be used to describe various elements, components, regions, layers, doping types and / or parts, these elements, components, regions, layers, doping types and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, doping type or part from another element, component, region, layer, doping type or part. Therefore, without departing from the teachings of the present 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] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0042] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that when the terms "consisting of" and / or "comprising" are used in this specification, the presence of the features, integers, steps, operations, elements and / or parts can be determined, but the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups is not excluded. At the same time, when used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0043] Embodiments of the invention are described herein with reference to cross-sectional views which are schematic diagrams of ideal embodiments (and intermediate structures) of the invention, such that variations in the shapes shown due to, for example, manufacturing techniques and / or tolerances are anticipated. Thus, embodiments of the invention should not be limited to the specific shapes of the regions shown herein, but rather include deviations in shapes due to, for example, manufacturing techniques. For example, an implanted region shown as a rectangle typically has rounded or curved features and / or an implant concentration gradient at its edges rather than a binary change from an implanted region to a non-implanted region. Similarly, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation is performed. Thus, the regions shown in the figures are schematic in nature, their shapes do not represent the actual shape of the region of the device, and do not limit the scope of the invention.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of the present disclosure, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0045] FIG. 1 is a schematic flow chart of a method for preparing a solar cell in some embodiments. As shown in FIG. 1 , in this embodiment, a method for preparing a solar cell is provided, comprising:

[0046] S102, providing a substrate.

[0047] A substrate for preparing a solar cell is provided, wherein the substrate is a doped substrate having doped ions that can provide carriers, and 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, gallium oxide, etc. As an example, in this embodiment, the constituent material of the substrate is doped single crystal silicon.

[0048] S104, forming a tunneling layer 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, forming an isolation structure including alternately stacked silicon oxide layers and doped buffer layers on a surface of the tunneling layer away from the substrate.

[0051] Specifically, an isolation structure is deposited on a surface of the tunneling layer away from the substrate, and the isolation structure includes silicon oxide layers and doped buffer layers alternately stacked along a first direction perpendicular to the substrate, wherein the silicon oxide layer has an isolation effect, which can block the diffusion of ions from one side of the silicon oxide layer to the other side of the silicon oxide layer under heating, and reduce the diffusion of ions from one side of the silicon oxide layer to the other side of the silicon oxide layer under heating; the doped buffer layer can serve as a buffer zone for ion diffusion, and ions diffuse and stay in the doped buffer layer, which reduces the diffusion of ions from one side of the doped buffer layer to the other side of the doped buffer layer 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, thereby avoiding affecting the passivation effect of the tunneling layer.

[0052] By providing alternately stacked silicon oxide layers and doped buffer layers, the diffusion of doped ions in the first doped layer to the tunnel layer during heating is blocked, while the impact on the transport of carriers in the solar cell in the first direction of the doped buffer layer is reduced.

[0053] It can be understood that the bottom layer close to the substrate and the top layer far from the substrate of the isolation structure are respectively any one of a silicon oxide layer and a doped buffer layer, and the bottom layer close to the substrate and the top layer far from the substrate of the isolation structure can be the same or different.

[0054] S108, forming a first doping layer on a surface of the isolation structure away from the substrate.

[0055] Specifically, a first doping layer is formed on the surface of the isolation structure away from the substrate, and the doping concentration of the first doping layer is greater than the doping concentration of the doping buffer layer. It can be understood that when there are doping ions in the first doping layer and doping ions in the doping buffer layer, or when there are no doping ions in the doping buffer layer and there are doping ions in the doping buffer layer, the concentration of doping ions in the first doping layer is greater than the concentration of doping ions in the doping buffer layer. There is an isolation structure between the first doping layer and the tunneling layer. During the process of annealing the first doping layer by an annealing process, the existence of the isolation structure can reduce the diffusion of doping ions in the first doping layer to the tunneling layer on the side of the isolation structure close to the substrate, reduce the influence of the annealing process matching on the passivation performance of the solar cell, and increase the process window of the annealing process.

[0056] In the above-mentioned method for preparing the solar cell, an isolation structure is formed between the first doping layer and the tunneling layer, and the doping concentration of the doping buffer layer in the isolation structure is less than the doping concentration of the first doping layer, so that the doping ions in the first doping layer diffuse into the doping buffer layer before diffusing into the tunneling layer, and the silicon oxide layer in the isolation structure can block the diffusion of the doping ions in the first doping layer into the tunneling layer and the substrate, avoiding the influence on the passivation effect of the tunneling layer, reducing the influence of the 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 doping ions in the first doping layer, and reducing the influence of the annealing process matching on the passivation performance of the solar cell.

[0057] Figure 2 is a cross-sectional schematic diagram of a solar cell after the first doping layer is formed in some embodiments. As shown in Figure 2, an isolation structure 104 including an alternating stack of silicon oxide layers 202 and doped buffer layers 204 is formed on the first surface of the substrate 102, thereby reducing the doping ions in the tunneling layer 108 that diffuse to the first surface of the substrate 102 under heating.

[0058] It can be understood that the substrate 102 includes a light-receiving surface and a backlight surface that are arranged opposite to each other in a first direction perpendicular to the substrate 102. The light-receiving surface is the surface of the solar cell facing the sunlight (the light-facing surface), and the backlight surface is the surface of the solar cell facing away from the sunlight. The first surface includes at least one of the light-receiving surface and the backlight surface.

[0059] Exemplarily, the first surface is the backlight surface, and the method for preparing the solar cell also 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 polysilicon doping layer arranged in sequence from the substrate 102 to a direction away from the substrate 102.

[0060] As shown in FIG2 , in one embodiment, the step of forming the first doping layer 106 on the surface of the isolation structure 104 away from the substrate 102 includes: forming the first doping layer 106 on the surface of the doped buffer layer 204 at the top of the isolation structure 104. Compared with the top layer of the isolation structure 104 being the silicon oxide layer 202, setting the top layer of the isolation structure 104 as the doped buffer layer 204 can avoid the problem that the doped ions in the first doping layer 106 diffuse through the silicon oxide layer 202 under the action of heating and high concentration gradient when the silicon oxide layer 202 is in contact with the first doping layer 106, thereby affecting the isolation effect of the silicon oxide layer 202, and improving the isolation effect of the silicon oxide layer 202 in the isolation structure 104, so as to further reduce the influence of the internal diffusion and improve the performance of the solar cell.

[0061] Figure 3 is a schematic cross-sectional view of a solar cell after forming a first doping layer in some embodiments, Figure 4 Schematic cross-sectional view of a solar cell after forming a first doping layer in some other embodiments, such as Figure 3 , Figure 4 As shown, in one embodiment, the doped buffer layer 204 includes one of a second doped layer 302 and an intrinsic layer 304; wherein the doping concentration of the second doped layer 302 is less than the doping concentration of the first doped layer 106. There is a concentration difference between the first doped layer 106 and the second doped layer 302 and the intrinsic layer 304. The doped ions in the first doped layer 106 can diffuse into the doped buffer layer 204 (the second doped layer 302 or the intrinsic layer 304), thereby reducing the doped ions diffused into 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, wherein the conductivity type includes N-type and P-type, the N-type doped ions include phosphorus, and the P-type doped ions include boron.

[0062] like Figure 4 As shown, in one embodiment, the buffer layer 204 includes a second doping layer 302 and an intrinsic layer 304 stacked along the first direction X; wherein the doping concentration of the second doping layer 302 is less than the doping concentration of the first doping layer 106. There is a concentration difference between the first doping layer 106 and the second doping layer 302 and the intrinsic layer 304 in the buffer layer 204, and the doping ions in the first doping layer 106 can diffuse into the doped buffer layer 204 (the second doping layer 302 and the intrinsic layer 304), thereby reducing the doping ions diffused into the tunneling layer 108 and the substrate 102, and reducing the influence of heating on the performance of the solar cell. Furthermore, the second doping layer 302 and the first doping layer 106 have the same conductivity type, wherein the conductivity type includes 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. While preventing the doped ions in the first doped layer 106 from diffusing to the tunneling layer 108 and the substrate 102 during heating, the impact on the transport of carriers in the solar cell in the first direction X is reduced.

[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 the second doping 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 close to the substrate 102 is a doped buffer layer 204 including at least the second doping layer 302 adjacent to the tunneling layer 108. This arrangement is conducive to the collection of carriers and improves the performance of solar cells. The isolation structure 104 reduces the influence of the annealing process on the passivation performance of the tunneling layer 108, thereby improving the performance of solar cells.

[0066] It is understandable that when the bottom layer of the isolation structure 104 is the doped buffer layer 204 including the second doped layer 302 and the 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] Exemplarily, the material of the tunneling layer 108 and the material of the silicon oxide layer 202 include silicon dioxide; the material of the second doping layer 302 and the material of the first doping layer 304 include doped polysilicon; and the material of the intrinsic layer 304 includes intrinsic polysilicon.

[0068] Exemplarily, along the direction away from the substrate 102, the surface of the substrate 102 is sequentially provided with a tunneling layer 108 (for example, with a thickness of 2nm-3nm), a second doping layer 302 (for example, with a thickness of 5nm-15nm), a silicon oxide layer 202 (for example, with a thickness of 1nm-2nm), an intrinsic layer 304 (for example, with a thickness of 5nm-10nm) and / or a second doping layer 302 (for example, with a thickness of 5nm-10nm) and a first doping layer 106 (for example, with a thickness of 50nm-80nm).

[0069] It should be understood that, although the various steps in the flowchart of FIG. 1 are shown in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in FIG. 1 may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the sub-steps or stages of other steps.

[0070] The present application also provides a solar cell, and the parts that are the same or corresponding to the embodiments in the above-mentioned method for preparing the solar cell will not be described in detail below. As shown in Figure 2, in some embodiments, the solar cell includes: a substrate 102, an isolation structure 104, a first doping layer 106 and a tunneling layer 108; the tunneling layer 108 is located on the surface of the substrate 102, the isolation structure 104 is located on the surface of the tunneling layer 108 away from the substrate 102, and the isolation structure 104 includes a silicon oxide layer 202 and a doped buffer layer 204 alternately stacked along a first direction X perpendicular to the substrate 102; the first doping layer 106 is located on the surface of the isolation structure 104 away from the substrate 102; wherein the doping concentration of the first doping layer 106 is greater than the doping concentration of the doped buffer layer 204.

[0071] By providing the alternately stacked silicon oxide layers 202 and doped buffer layers 204 , the doped ions in the first doped layer 106 are blocked from diffusing to the tunnel layer 108 during heating, while reducing the impact on the transport of carriers in the solar cell in the first direction of the doped buffer layer 204 .

[0072] It is understandable that the bottom layer of the isolation structure 104 close to 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 close to the substrate 102 and the top layer away from the substrate 102 can be the same or different.

[0073] In the above-mentioned solar cell, an isolation structure 104 is arranged between the first doping layer 106 and the tunneling layer 108, and the doping concentration of the doped buffer layer 204 in the isolation structure 104 is lower than the doping concentration of the first doping layer 106, so that the doped ions in the first doping layer 106 diffuse into the doped buffer layer 204 before diffusing into the tunneling layer 108, and the silicon oxide layer 202 in the isolation structure 104 can block the diffusion of the doped ions in the first doping layer 106 into the tunneling layer 108 and the substrate 102, thereby avoiding the influence on the passivation effect of the tunneling layer 108, reducing the influence of the 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 doping layer, and reducing the influence of the annealing process matching on the passivation performance of the solar cell.

[0074] As shown in FIG2 , in one embodiment, the top layer of the isolation structure 104 away from the substrate 102 is a doped buffer layer 204. Compared with the case where the top layer of the isolation structure 104 is the silicon oxide layer 202, the top layer of the isolation structure 104 is the doped buffer layer 204, so that the problem that the doped ions in the first doped layer 106 diffuse through the silicon oxide layer 202 under the action of heating and high concentration gradient when the silicon oxide layer 202 is in contact with the first doped layer 106, and the isolation effect of the silicon oxide layer 202 is improved, so as to further reduce the influence of the internal diffusion and improve 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. There is a concentration difference between the first doped layer 106, the second doped layer 302, and the intrinsic layer 304. The doped ions in the first doped layer 106 can diffuse into the doped buffer layer 204 (the second doped layer 302 or the intrinsic layer 304), thereby reducing the doped ions diffused into 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, wherein the conductivity type includes N-type and P-type.

[0076] As shown in FIG. 2 , in one embodiment, the buffer layer 204 includes an intrinsic layer 304 and a second doping layer 302 stacked along the first direction X; wherein the doping concentration of the second doping layer 302 is less than the doping concentration of the first doping layer 106. There is a concentration difference between the first doping layer 106 and the second doping layer 302 and the intrinsic layer 304 in the buffer layer 204. The doping ions in the first doping layer 106 can diffuse into the doped buffer layer 204 (the second doping layer 302 and the intrinsic layer 304), thereby reducing the doping ions diffused into the tunneling layer 108 and the substrate 102, and reducing the influence of heating on the performance of the solar cell. Furthermore, the second doping layer 302 and the first doping layer 106 have the same conductivity type, wherein the conductivity type includes N-type and P-type.

[0077] like Figure 4 As shown, in one embodiment, the doped buffer layer 204 at the bottom of the isolation structure 104 close to the substrate 102 includes at least the second doped layer 302 adjacent to the surface of the tunneling layer 108 away from the substrate 102. This arrangement is conducive to the collection of carriers and improves the performance of the solar cell. The isolation structure 104 reduces the influence of the annealing process on the passivation performance of the tunneling layer 108, thereby improving the performance of the solar cell.

[0078] It can be understood that when the doped buffer layer 204 includes the second doped layer 302 and the 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] The present disclosure also provides a photovoltaic assembly, comprising a plurality of solar cells as described above, and / or a plurality of solar cells manufactured using the method for manufacturing a solar cell as described above.

[0081] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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-mentioned embodiments only express several implementation methods of the embodiments of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the embodiments of the present disclosure, and these all belong to the protection scope of the embodiments of the present disclosure.

Claims

1. A solar cell, characterized in that: include: substrate; A tunneling layer, located on the surface of the substrate; An isolation structure, located on a surface of the tunneling layer away from the substrate, the isolation structure comprising silicon oxide layers and doped buffer layers alternately stacked along a first direction perpendicular to the substrate; A first doping layer is located on a surface of the isolation structure away from the substrate; Wherein, the doping concentration of the first doping layer is greater than the doping concentration of the doping buffer layer.

2. The solar cell according to claim 1, characterized in that The top layer of the isolation structure away from the substrate is a doped buffer layer.

3. The solar cell according to claim 1 or 2, characterized in that: 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; The second doping layer and the first doping layer have the same conductivity type, and the doping concentration of the second doping layer is less than the doping concentration of the first doping layer.

4. The solar cell according to claim 3, characterized in that: The bottom layer of the isolation structure close to the substrate is a doped buffer layer including at least the second doped layer adjacent to the surface of the tunneling layer away from 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: providing a substrate; forming a tunneling layer on the surface of the substrate; forming an isolation structure on a surface of the tunneling layer away from the substrate, the isolation structure comprising silicon oxide layers and doped buffer layers alternately stacked along a first direction perpendicular to the substrate; forming a first doping layer on a surface of the isolation structure away from the substrate; Wherein, the doping concentration of the first doping layer is greater than the doping concentration of the doping buffer layer.

7. The method for preparing a solar cell according to claim 6, characterized in that: The step of forming a first doping layer on a surface of the isolation structure away from the substrate comprises: The first doping layer is formed on the surface of the doping buffer layer at the top layer of the isolation structure.

8. The method for preparing a solar cell according to claim 6 or 7, characterized in that: 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; The second doping layer and the first doping layer have the same conductivity type, and the doping concentration of the second doping layer is less than the doping concentration of the first doping layer.

9. The method for preparing a solar cell according to claim 8, characterized in that: The step of forming an isolation structure on a surface of the tunneling layer away from the substrate comprises: forming the second doping layer adjacent to the tunneling layer on a surface of the tunneling layer away from the substrate; Wherein, the bottom layer of the isolation structure is a doped buffer layer which at least includes the second doped layer adjacent to the tunneling layer.

10. A photovoltaic module, characterized in that: The invention comprises a plurality of solar cells according to any one of claims 1 to 5, and / or a plurality of solar cells manufactured by the method for manufacturing a solar cell according to any one of claims 6 to 9.

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