Solar cell, preparation method thereof and photovoltaic module

Abstract

The invention relates to a solar cell, a preparation method thereof and a photovoltaic module, and the solar cell comprises a first doping layer which is located on a substrate; the barrier layer is located on the top surface, away from the substrate, of the first doping layer; the second doping layer is located on the top surface, away from the substrate, of the barrier layer, penetrates through the barrier layer and the first doping layer in the first direction perpendicular to the substrate and is adjacent to the first doping layer; wherein the first doped layer and the second doped layer have the same conduction type, and the doping concentration of the first doped layer is smaller than that of the second doped layer. The production period of the solar cell is shortened, and the manufacturing cost is reduced.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a solar cell and a preparation method thereof, and a photovoltaic module. Background Art

[0002] Solar cells can convert solar energy into electrical energy and are pollution-free. With the development of solar cell technology, how to balance the performance and cost of solar cells has become an urgent problem to be solved. Summary of the invention

[0003] Based on this, the present disclosure provides a solar cell and a preparation method thereof, and a photovoltaic module, which can improve the performance of the solar cell.

[0004] In a first aspect, a solar cell is provided, comprising:

[0005] A first doped layer, located on the substrate;

[0006] a barrier layer, located on a top surface of the first doped layer away from the substrate;

[0007] A second doping layer, located on a top surface of the barrier layer away from the substrate, penetrates the barrier layer and the first doping layer along a first direction perpendicular to the substrate, and is adjacent to the first doping layer;

[0008] The first doping layer and the second doping layer have the same conductivity type, and the doping concentration of the first doping layer is less than the doping concentration of the second doping layer.

[0009] In one embodiment, the second doped layer comprises:

[0010] a first portion, located in the first doped layer and adjacent to the first doped layer;

[0011] a second portion, located on a top surface of the barrier layer away from the substrate, penetrating the barrier layer along the first direction, and extending to be adjacent to the first portion;

[0012] The first portion and the first doping layer are formed by doping the same film layer.

[0013] In one embodiment, the solar cell further comprises:

[0014] The first electrode is located on a top surface of the second doping layer away from the substrate and is connected to the second doping layer.

[0015] In one of the embodiments, an orthographic projection of a portion of the second doped layer penetrating through the barrier layer on the substrate covers an orthographic projection of the first electrode on the substrate.

[0016] In one embodiment, the solar cell further comprises:

[0017] a third doping layer, in a second direction parallel to the substrate, the third doping layer being spaced apart from the first doping layer and the second doping layer respectively;

[0018] A second electrode is located on a top surface of the third doped layer away from the substrate and connected to the third doped layer;

[0019] The third doping layer and the first doping layer have opposite conductivity types, and the first doping layer and the third doping layer are located on the same side of the substrate.

[0020] In a second aspect, a method for preparing a solar cell is provided, comprising:

[0021] providing a substrate;

[0022] forming a stacked structure on the substrate, the stacked structure comprising a first doping layer, a barrier layer, and a second doping layer which are sequentially adjacently arranged in a direction away from the substrate;

[0023] The second doping layer penetrates the barrier layer and the first doping layer along a first direction perpendicular to the substrate and is adjacent to the first doping layer; the first doping layer and the second doping layer have the same conductivity type, and the doping concentration of the first doping layer is less than the doping concentration of the second doping layer.

[0024] In one embodiment, forming a stacked structure on the substrate includes:

[0025] forming a first semiconductor layer and a barrier material layer in sequence on the substrate, wherein the barrier material layer is located on a top surface of the first semiconductor layer away from the substrate;

[0026] forming a first groove in the barrier material layer, wherein the first groove at least penetrates the barrier material layer along the first direction to form a barrier layer composed of the remaining barrier material layer;

[0027] forming a second semiconductor layer in the first trench, wherein the second semiconductor layer is adjacent to the first semiconductor layer and extends along the sidewall of the first trench to a top surface of the barrier layer away from the substrate;

[0028] performing a doping process on the second semiconductor layer and the first semiconductor layer;

[0029] The doped second semiconductor layer forms the second doped layer, and the doped first semiconductor layer between the barrier layer and the substrate forms the first doped layer.

[0030] In one embodiment, the first trench is formed in the barrier material layer by using laser patterning technology.

[0031] In one embodiment, the first semiconductor layer is exposed at the bottom of the first trench, and the second doped layer includes a first portion and a second portion. The doped first semiconductor layer at the bottom of the first trench forms the first portion, and the doped second semiconductor layer forms the second portion.

[0032] In one embodiment, the second semiconductor layer and the first semiconductor layer are doped using a diffusion process.

[0033] In a third aspect, a photovoltaic module is provided, comprising the solar cell as described above, and / or a solar cell manufactured using the method for manufacturing a solar cell as described above.

[0034] In the above solar cell, the barrier layer can block the doping elements in the second doping layer from entering the first doping layer, weakening the influence of the diffusion speed of the doping elements in the second doping layer on the passivation effect of the first doping layer, removing the restriction of the diffusion speed of the doping elements in the second doping layer on the deposition speed of the second doping layer, shortening the production cycle of the solar cell and reducing the manufacturing cost without affecting the solar cell. In addition, the top layer far away from the substrate is the second doping layer with a high doping concentration, which can achieve good contact.

[0035] In the above-mentioned method for preparing solar cells, the barrier layer in the laminated structure can block the doping elements in the second doping layer from entering the first doping layer, weakening the influence of the diffusion speed of the doping elements in the second doping layer on the passivation effect of the first doping layer, removing the restriction of the diffusion speed of the doping elements in the second doping layer on the deposition speed of the second doping layer, shortening the production cycle of the solar cell without affecting the solar cell, and reducing the manufacturing cost. In addition, the top layer of the laminated structure away from the substrate is the second doping layer with a high doping concentration, which can achieve good contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 is a schematic diagram of a process for preparing a solar cell in some embodiments;

[0038] Figure 2is a cross-sectional schematic diagram of a solar cell in some embodiments;

[0039] Figure 3 is a schematic cross-sectional view of a solar cell after a first groove is formed in some embodiments;

[0040] Figure 4 is a schematic cross-sectional view of a solar cell after a second semiconductor layer is formed in some embodiments;

[0041] Figure 5 is a schematic cross-sectional view of a solar cell after a second doping layer is formed in some embodiments;

[0042] Figure 6 Schematic cross-sectional views of solar cells in other embodiments.

[0043] Description of reference numerals:

[0044] Substrate 102, stacked structure 104, first doped layer 106, barrier layer 108, second doped layer 110, first tunneling layer 112, first semiconductor layer 202, barrier material layer 204, first tunneling layer 206, first trench 208, second semiconductor layer 210, barrier layer 302, second doped layer 304, first doped layer 306, first portion 308, second portion 310, stacked structure 312, first electrode 314, first tunneling layer 402, first doped layer 404, barrier layer 406, second doped layer 408, stacked structure 410, third doped layer 412, second tunneling layer 414, second electrode 416, passivation layer 418, anti-reflection layer 420, first electrode 422. DETAILED DESCRIPTION

[0045] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0046] 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 this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0047] 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, a first doped layer may be referred to as a second doped layer, and similarly, a second doped layer may be referred to as a first doped layer, and both the first doped layer and the second doped layer are doped layers, but they are not the same doped layer.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] Figure 1 is a schematic diagram of a process for preparing a solar cell in some embodiments, Figure 2 is a schematic cross-sectional view of a solar cell in some embodiments, such as Figure 1 , Figure 2 As shown, in this embodiment, a method for preparing a solar cell is provided, comprising:

[0052] S102, providing a substrate.

[0053] A substrate 102 is provided, and the substrate 102 has a light-receiving surface and a backlight surface which are arranged opposite to each other. 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 substrate 102 which is arranged opposite to the light-receiving surface. The substrate 102 includes a semiconductor doped 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 constituent material of the substrate 102 is doped single crystal silicon.

[0054] S104, forming a stacked structure on the substrate, the stacked structure comprising a first doping layer, a barrier layer, and a second doping layer that are sequentially adjacently disposed in a direction away from the substrate.

[0055] A stacked structure 104 is formed on a substrate 102, and the stacked structure 104 includes a first doping layer 106, a barrier layer 108, and a second doping layer 110 which are adjacently arranged in sequence along a direction away from the substrate 102, wherein the second doping layer 110 penetrates the barrier layer 108 and the first doping layer 106 along a first direction perpendicular to the substrate 102, and is adjacent to the first doping layer 106; the first doping layer 106 and the second doping layer 110 have the same conductivity type, and the doping concentration of the first doping layer 106 is less than the doping concentration of the second doping layer 110.

[0056] It is understandable that the laminated structure 104 is located on the light-facing side and / or the backlight side of the substrate 102. When the laminated structure 104 is located on the backlight side of the substrate 102, the area of ​​the solar cell receiving sunlight is not affected, thereby improving the photoelectric conversion efficiency of the solar cell.

[0057] The top surface of the first doping layer 106 away from the substrate 102 is adjacent to the bottom surface of the barrier layer 108 close to the substrate 102 , and the second doping layer 110 includes a portion adjacent to the top surface of the barrier layer 108 away from the substrate 102 and a portion penetrating the barrier layer 108 . Adjacent means adjacent and in contact.

[0058] The conductivity types include N-type and P-type. The first doped layer 106 and the second doped layer 110 are both N-type or both P-type. The conductivity types of the substrate 102 and the first doped layer 106 are the same or opposite. The same conductivity type means that the conductivity types of the substrate 102 and the first doped layer 106 are both N-type or both P-type. The opposite conductivity types means that one of the substrate 102 and the first doped layer 106 is N-type and the other is P-type.

[0059] Exemplarily, the N-type doping element includes one or more of phosphorus, arsenic and antimony, and the P-type doping element includes one or more of boron, aluminum, gallium and indium. As an example, in this embodiment, the N-type doping element is phosphorus, and the P-type doping element is boron.

[0060] In the above-mentioned method for preparing solar cells, the barrier layer 108 in the stacked structure 104 can block the doping elements in the second doping layer 110 from entering the first doping layer 106, weakening the influence of the diffusion speed of the doping elements in the second doping layer 110 on the passivation effect of the first doping layer 106, removing the restriction of the diffusion speed of the doping elements in the second doping layer 110 on the deposition speed of the second doping layer 110, shortening the production cycle of the solar cell without affecting the solar cell, and reducing the manufacturing cost. In addition, the top layer of the stacked structure 104 away from the substrate 102 is the second doping layer 110 with a high doping concentration, which can achieve good contact.

[0061] like Figure 2 As shown, in one embodiment, the stacked structure further includes a first tunneling layer 112, the first tunneling layer 112 is located between the substrate 102 and the first doped layer 106, and the surfaces of the first tunneling layer 112 that are arranged opposite to each other are respectively adjacent to the substrate 102 and the bottom surface of the first doped layer 106 close to the substrate 102. By providing the first tunneling layer 112, the recombination of electrons and holes can be prevented, the current collection and transmission efficiency can be improved, and the conversion efficiency of the solar cell can be improved. Exemplarily, the material of the first tunneling layer 112 includes silicon dioxide.

[0062] Figure 3 is a schematic cross-sectional view of a solar cell after a first groove is formed in some embodiments, Figure 4 is a schematic cross-sectional view of a solar cell after forming a second semiconductor layer in some embodiments, Figure 5 is a schematic cross-sectional view of a solar cell after forming a second doping layer in some embodiments, such as Figure 3-Figure 5 As shown, in one embodiment, forming the stacked structure 104 on the substrate 102 includes steps S202 - S208 .

[0063] S202, forming a first semiconductor layer and a barrier material layer in sequence on the substrate.

[0064] like Figure 3 As shown, a substrate 102 is provided, and the surface of the substrate 102 is polished. A deposition process, such as a low-pressure chemical vapor deposition process or a plasma enhanced chemical vapor deposition process, is used to sequentially form a first semiconductor layer 202 and a barrier material layer 204 on the substrate 102, wherein the top surface of the first semiconductor layer 202 away from the substrate 102 is adjacent to the bottom surface of the barrier material layer 204 close to the substrate 102.

[0065] Exemplarily, the material of the first semiconductor layer 202 includes intrinsic amorphous silicon and / or intrinsic polysilicon, and the material of the barrier material layer 204 includes oxide (eg, silicon dioxide) and nitride (eg, silicon nitride).

[0066] In one embodiment, before forming the first semiconductor layer 202 on the substrate 102, the method for preparing a solar cell further includes: forming a first tunneling layer 206 on the surface of the substrate 102, wherein the first tunneling layer 206 is away from the top surface of the substrate 102 and is adjacent to the bottom surface of the first semiconductor layer 202 close to the substrate 102. Exemplarily, the first tunneling layer 206 is formed on the surface of the substrate 102 by a plasma enhanced chemical vapor deposition process.

[0067] As an example, in a first direction perpendicular to the substrate 102, the thickness of the first tunneling layer 206 includes 1nm-1.5nm, for example, 1nm, 1.2nm, 1.5nm, etc.; the thickness of the first semiconductor layer 202 includes 60nm-100nm, for example, 60nm, 65nm, 70nm, 80nm, 100nm, etc.; the thickness of the blocking material layer 204 includes 1nm-1.5nm, for example, 1nm, 1.2nm, 1.5nm, etc.

[0068] S204, forming a first trench in the barrier material layer.

[0069] like Figure 3As shown, an etching process is used to form a first groove 208 in the barrier material layer 204. The first groove 208 penetrates the barrier material layer 204 at least along the first direction to form a barrier layer 302 composed of the remaining barrier material layer 204. The first groove 208 defines the shape and position of the portion of the second doped layer penetrating the barrier layer 302.

[0070] In one embodiment, laser patterning technology is used to form the first trench 208 in the barrier material layer 204. The method of forming the first trench 208 does not require a mask pattern layer, has a simple process, low cost, and high position accuracy of the first trench 208.

[0071] S206 , forming a second semiconductor layer in the first trench.

[0072] like Figure 4 As shown, a deposition process, such as a low pressure chemical vapor deposition process or a plasma enhanced chemical vapor deposition process, is used to form a second semiconductor layer 210 in the first trench 208. The second semiconductor layer 210 is adjacent to the first semiconductor layer 202 and extends along the sidewall of the first trench 208 to the top surface of the barrier layer 302 away from the substrate 102. Exemplarily, the material of the second semiconductor layer 210 includes intrinsic amorphous silicon and / or intrinsic polycrystalline silicon.

[0073] It can be understood that, when the first semiconductor layer 202 is exposed at the bottom of the first trench 208, the second semiconductor layer 210 in the first trench 208 is adjacent to the first semiconductor layer 202 exposed by the first trench 208. When the first trench 208 penetrates the first semiconductor layer 202, the sidewall of the second semiconductor layer 210 in the first trench 208 is adjacent to the first semiconductor layer 202 exposed by the sidewall of the first trench 208; Figure 3 and Figure 4 An example is given in which the bottom of the first trench 202 exposes the top surface of the first semiconductor layer 202 .

[0074] S208, performing doping treatment on the second semiconductor layer and the first semiconductor layer.

[0075] like Figure 5 As shown, the first semiconductor layer 202 and the second semiconductor layer 210 are doped, wherein the doped second semiconductor layer 210 forms the second doped layer 304, the first semiconductor layer 202 doped between the barrier layer 302 and the substrate 102 forms the first doped layer 306, and the stacked structure 312 includes the first tunneling layer 206, the barrier layer 302, the second doped layer 304 and the first doped layer 306.

[0076] The barrier layer 302 blocks the diffusion of doping elements from the second semiconductor layer 210 to the first semiconductor layer 202 between the barrier layer 302 and the substrate 102 and in the substrate 102 in the area covered by the orthographic projection of the barrier layer 302. Therefore, the doping concentration of the doped first semiconductor layer 202 (first doping layer 306) between the barrier layer 302 and the substrate 102 is less than the doping concentration of the doped second semiconductor layer 210 (second doping layer 304). The first doping layer 306 with low doping concentration in the solar cell is close to the substrate 102, which improves the passivation effect of the solar cell; the second doping layer 304 with high doping concentration is located on the side of the solar cell away from the substrate 102, which can form a good contact and improve the conversion efficiency of the solar cell as a whole. The existence of the barrier layer 302 makes it unnecessary to reduce the deposition rate of the second semiconductor layer 210 to increase the second semiconductor layer 210 blocking the doping elements from the first semiconductor layer 202 during the process, which can increase the deposition rate of the second semiconductor layer 210, shorten the process time, and reduce the manufacturing cost of the solar cell.

[0077] The first doping layer 306 and the second doping layer 304 are formed by doping in the same step, which simplifies the process of the solar cell, shortens the manufacturing cycle of the solar cell, and reduces the preparation cost of the solar cell.

[0078] In one embodiment, a diffusion process is used to dope the second semiconductor layer 210 and the first semiconductor layer 202. While the first semiconductor layer 202 and the second semiconductor layer 210 are doped, the first semiconductor layer 202 and the second semiconductor layer 210 are crystallized, and amorphous silicon is converted into polycrystalline silicon.

[0079] like Figure 3 , Figure 5As shown, in one embodiment, the first semiconductor layer 202 is exposed at the bottom of the first groove 208, and the second doped layer 304 includes a first portion 308 and a second portion 310. The doped first semiconductor layer 202 at the bottom of the first groove 208 forms the first portion 308, and the doped second semiconductor layer 210 forms the second portion 310. The first portion 308 is adjacent to the first doped layer 306, and the first portion 308 and the first doped layer 306 are formed by doping the same film layer (the first semiconductor layer 202). At this time, there is no obvious boundary between the first doped layer 306 and the second doped layer 304, and the first doped layer 306 and the second doped layer 304 have good contact, which increases the carrier transmission rate. In addition, the first semiconductor layer 202 is exposed at the bottom of the first groove 208, which shortens the time for forming the first groove 208 and reduces the material of the second semiconductor layer 210, thereby increasing the photoelectric conversion efficiency of the solar cell and reducing the manufacturing cost of the solar cell.

[0080] Figure 6 Schematic cross-sectional views of solar cells in other embodiments, such as Figure 6 As shown, in one embodiment, the stacked structure 410 includes a first tunneling layer 402, a first doping layer 404, a barrier layer 406 and a second doping layer 408; the first groove 208 penetrates the first semiconductor layer 202, and the second doping layer 304 in the first groove 208 is adjacent to the first doping layer 306. At this time, the second doping layer 408 is an integrated structure, which avoids the influence of natural oxidation on the surface of the first semiconductor layer on the resistance of the second doping layer 408, thereby increasing the conversion efficiency of the solar cell.

[0081] like Figure 5 As shown, in one embodiment, the method for preparing a solar cell further includes: forming a first electrode 314 on the top surface of the second doping layer 304 away from the substrate 102, the first electrode 314 is electrically connected to the second doping layer 304, collecting carriers through the first electrode 314, leading out one end of the solar cell, and providing current to the load. The doping concentration of the second doping layer 304 is relatively high, so that there is good contact between the first electrode 314 and the second doping layer 304, reducing the contact resistance in the solar cell.

[0082] Furthermore, the orthographic projection of the portion of the second doping layer 304 that penetrates the barrier layer 302 on the substrate 102 covers the orthographic projection of the first electrode 314 on the substrate 102, thereby increasing the rate at which the first electrode 314 collects carriers and improving the conversion efficiency of the solar cell.

[0083] In one of the embodiments, the method for preparing a solar cell also includes: forming a third doped layer on the substrate 102, the third doped layer having a conductivity type opposite to that of the first doped layer; forming a second electrode on a surface of the third doped layer away from the substrate 102, the second electrode being electrically connected to the third doped layer, collecting carriers through the second electrode, leading out one end of the solar cell, and providing current to a load, wherein the third doped layer and the first doped layer are respectively located on opposite surfaces of the substrate 102.

[0084] like Figure 6 As shown, in one embodiment, the substrate 102 includes a first region 1, an isolation region 2, and a second region 3 adjacent to each other in sequence, the first region 1 and the second region 3 are arranged at intervals, and the orthographic projection of the portion of the second doping layer 408 that penetrates the barrier layer 406 on the substrate 102 is located in the first region 1, and the method for preparing the solar cell further includes: performing laser grooving, etching and removing the stacked structure 410 of the isolation region 2 and the second region 3, exposing the substrate 102 of the isolation region 2 and the second region 3, and the remaining stacked structure 410 covers the first region 1.

[0085] like Figure 6 As shown, in one of the embodiments, the method for preparing a solar cell further includes: steps S302-S304.

[0086] S302 , forming a third doping layer 412 on the substrate 102 .

[0087] Specifically, a deposition process, such as a plasma enhanced chemical vapor deposition process, is used to form a third semiconductor layer on one side of the first doped layer 404 formed on the substrate 102, the third semiconductor layer is located in the second region 3, and extends to cover the isolation region 2 and the first region 1; illustratively, before forming the third semiconductor layer, it also includes forming a second tunneling layer 414 on the surface of the substrate 102, the second tunneling layer 414 is located between the substrate 102 and the third semiconductor layer, and between the stacked structure 410 and the third semiconductor layer; secondly, the third semiconductor layer is doped by a diffusion process to form a third doping material layer, the conductivity type of the third doping material layer is opposite to the conductivity type of the first doping layer 404; thirdly, laser grooving is performed to remove the third doping material layer covering the stacked structure 410 and the isolation region 2, to form a third doping layer 412 located in the second region 3, and further, the second tunneling layer 414 covering the stacked structure 410 and the isolation region 2 is removed.

[0088] In a second direction parallel to the substrate 102, the third doping layer 412 is spaced apart from the first doping layer 404 and the second doping layer 408, respectively. The third doping layer 412 is located in the second region 3 and is located on the same side of the substrate 102 as the first doping layer 404. At the same time, the conductivity types of the third doping layer 412 and the first doping layer 404 are opposite.

[0089] S302 , forming a second electrode 416 on a top surface of the third doped layer away from the substrate 102 .

[0090] Specifically, first, a passivation layer 418 and an anti-reflection layer 420 are sequentially formed on opposite surfaces of the substrate 102. The passivation layer 418 on the side of the first doped layer 402 formed on the substrate 102 is located on the top surface of the second doped layer 408 away from the substrate 102, and extends along the sidewall of the second doped layer 408 to cover the surface of the substrate 102 of the isolation region 2 and the top surface of the third doped layer 412 away from the substrate 102. As an example, the material of the passivation layer 418 includes aluminum oxide, and the material of the anti-reflection layer 420 includes silicon nitride. Secondly, a second electrode 416 is formed on the top surface of the third doped layer 412 away from the substrate 102 by a screen printing process. The second electrode 416 penetrates the passivation layer 418 and the anti-reflection layer 420, and is electrically connected to the third doped layer 412. Carriers are collected through the second electrode 416, and the other end of the solar cell is led out to provide current to the load. Furthermore, in the process of forming the second electrode 416, a first electrode 422 is formed on the top surface of the second doping layer 408 away from the substrate 102, and the first electrode 422 penetrates the passivation layer 418 and the anti-reflection layer 420, and is electrically connected to the second doping layer 408. As an example, the materials of the first electrode 422 and the second electrode 416 include metal silver, metal copper, etc.

[0091] It is understandable that when the first doping layer 408 and the third doping layer 412 are located on the backlight side of the substrate 102 , the first electrode 422 and the second electrode 416 will not block the solar energy irradiating into the solar cell, thereby increasing the conversion efficiency of the solar cell.

[0092] Exemplarily, in a first direction perpendicular to the substrate 102, the thickness of the second tunneling layer 414 includes 1nm-2nm, for example, 1nm, 1.2nm, 1.5nm, 2nm, etc.; the thickness of the third doping layer 412 includes 100nm-250nm, for example, 100nm, 120nm, 150nm, 200nm, 250nm, etc.

[0093] It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1At least part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0094] The present disclosure also provides a solar cell, and the parts that are the same or corresponding to the embodiments of the solar cell preparation method described above will not be described in detail below. Figure 2 As shown, in this embodiment, the solar cell includes: a first doping layer 106, a barrier layer 108 and a second doping layer 110; the first doping layer 106 is located on a substrate 102; the barrier layer 108 is located on a top surface of the first doping layer 106 away from the substrate 102; the second doping layer 110 is located on a top surface of the barrier layer 108 away from the substrate 102, and the second doping layer 110 penetrates the barrier layer 108 and the first doping layer 106 along a first direction perpendicular to the substrate 102, and is adjacent to the first doping layer 106; wherein the first doping layer 106 and the second doping layer 110 have the same conductivity type, and the doping concentration of the first doping layer 106 is less than the doping concentration of the second doping layer 110.

[0095] In the above solar cell, the barrier layer 108 can block the doping elements in the second doping layer 110 from entering the first doping layer 106, weakening the influence of the diffusion speed of the doping elements in the second doping layer 110 on the passivation effect of the first doping layer 106, removing the restriction of the diffusion speed of the doping elements in the second doping layer 110 on the deposition speed of the second doping layer 110, shortening the production cycle of the solar cell without affecting the solar cell, and reducing the manufacturing cost. In addition, the top layer away from the substrate 102 is the second doping layer 110 with a high doping concentration, which can achieve good contact.

[0096] like Figure 2 As shown, in one embodiment, the solar cell further includes: a first tunneling layer 112, the first tunneling layer 112 is located between the substrate 102 and the first doping layer 106, and the surfaces of the first tunneling layer 112 that are arranged opposite to each other are respectively adjacent to the substrate 102 and the bottom surface of the first doping layer 106 close to the substrate 102. By providing the first tunneling layer 112, the recombination of electrons and holes can be prevented, the current collection and transmission efficiency can be improved, and the conversion efficiency of the solar cell can be improved.

[0097] like Figure 5As shown, in one embodiment, the second doping layer 304 includes a first portion 308 and a second portion 310; the first portion 308 is located in the first doping layer 306 and is adjacent to the first doping layer 306, wherein the first portion 308 and the first doping layer 306 are formed by doping the same film layer (the first semiconductor layer 202); the second portion 310 is located on the top surface of the barrier layer 302 away from the substrate 102, penetrates the barrier layer 302 along the first direction, and extends to be adjacent to the first portion 308. There is no obvious boundary between the first doping layer 306 and the second doping layer 304 formed by doping the same film layer (the first semiconductor layer 202), so that the first doping layer 306 and the second doping layer 304 have good contact, which increases the carrier transmission rate. When the material of the second doping layer 304 is reduced and the photoelectric conversion efficiency of the solar cell is increased, the manufacturing cost of the solar cell is reduced.

[0098] like Figure 6 As shown, in one embodiment, the second doping layer 408 is an integrated structure, penetrating the barrier layer 302 and the first doping layer 402 along the first direction, avoiding the influence of natural oxidation on the resistance of the second doping layer 408, and increasing the conversion efficiency of the solar cell.

[0099] like Figure 5 As shown, in one embodiment, the solar cell further includes: a first electrode 314, the first electrode 314 is located on the top surface of the second doped layer 304 away from the substrate 102, and is connected to the second doped layer 304. Carriers are collected by the first electrode 314, and one end of the solar cell is led out to provide current to the load. The doping concentration of the second doped layer 304 is relatively high, so that there is good contact between the first electrode 314 and the second doped layer 304, thereby reducing the contact resistance in the solar cell.

[0100] like Figure 5 As shown, in one embodiment, the orthographic projection of the portion of the second doping layer 304 that penetrates the barrier layer 302 on the substrate 102 covers the orthographic projection of the first electrode 314 on the substrate 102, thereby increasing the rate at which the first electrode 314 collects carriers and improving the conversion efficiency of the solar cell.

[0101] like Figure 6As shown, in one embodiment, the solar cell further includes: a third doping layer 412 and a second electrode 416, and in a second direction parallel to the substrate 102, the third doping layer 412 is spaced apart from the first doping layer 404 and the second doping layer 408, respectively; wherein the third doping layer 412 and the first doping layer 404 have opposite conductivity types, and the first doping layer 404 and the third doping layer 412 are located on the same side of the substrate 102. The second electrode 416 is located on the top surface of the third doping layer 412 away from the substrate 102, and is connected to the third doping layer 412. Carriers are collected by the second electrode 416, and the other end of the solar cell is led out to provide current to the load. As an example, the materials of the first electrode 314 and the second electrode 416 include metal silver, metal copper, etc.

[0102] Exemplarily, the material of the first doping layer 404 , the second doping layer 408 , and the third doping layer 412 includes doped polysilicon.

[0103] The present disclosure also provides a photovoltaic module, including the solar cell as described above, and / or a solar cell manufactured using the method for manufacturing the solar cell as described above.

[0104] 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 of 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.

[0105] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A solar cell, characterized in that: include: A first doped layer, located on the substrate; a barrier layer, located on a top surface of the first doped layer away from the substrate; A second doping layer, located on a top surface of the barrier layer away from the substrate, penetrates the barrier layer and the first doping layer along a first direction perpendicular to the substrate, and is adjacent to the first doping layer; The first doping layer and the second doping layer have the same conductivity type, and the doping concentration of the first doping layer is less than the doping concentration of the second doping layer.

2. The solar cell according to claim 1, characterized in that The second doping layer comprises: a first portion, located in the first doped layer and adjacent to the first doped layer; a second portion, located on a top surface of the barrier layer away from the substrate, penetrating the barrier layer along the first direction, and extending to be adjacent to the first portion; The first portion and the first doping layer are formed by doping the same film layer.

3. The solar cell according to claim 1, characterized in that The solar cell further comprises: The first electrode is located on a top surface of the second doping layer away from the substrate and is connected to the second doping layer.

4. The solar cell according to claim 3, characterized in that: The orthographic projection of the portion of the second doping layer that penetrates the barrier layer on the substrate covers the orthographic projection of the first electrode on the substrate.

5. The solar cell according to claim 1, characterized in that: The solar cell further comprises: a third doping layer, in a second direction parallel to the substrate, the third doping layer being spaced apart from the first doping layer and the second doping layer respectively; A second electrode is located on a top surface of the third doped layer away from the substrate and connected to the third doped layer; The third doping layer and the first doping layer have opposite conductivity types, and the first doping layer and the third doping layer are located on the same side of the substrate.

6. A method for preparing a solar cell, characterized in that: include: providing a substrate; forming a stacked structure on the substrate, the stacked structure comprising a first doping layer, a barrier layer, and a second doping layer which are sequentially adjacently arranged in a direction away from the substrate; The second doping layer penetrates the barrier layer and the first doping layer along a first direction perpendicular to the substrate and is adjacent to the first doping layer; the first doping layer and the second doping layer have the same conductivity type, and the doping concentration of the first doping layer is less than the doping concentration of the second doping layer.

7. The preparation method according to claim 6, characterized in that: The forming of a stacked structure on the substrate comprises: forming a first semiconductor layer and a barrier material layer in sequence on the substrate, wherein the barrier material layer is located on a top surface of the first semiconductor layer away from the substrate; forming a first groove in the barrier material layer, wherein the first groove at least penetrates the barrier material layer along the first direction to form a barrier layer composed of the remaining barrier material layer; forming a second semiconductor layer in the first trench, wherein the second semiconductor layer is adjacent to the first semiconductor layer and extends along the sidewall of the first trench to a top surface of the barrier layer away from the substrate; performing a doping process on the second semiconductor layer and the first semiconductor layer; The doped second semiconductor layer forms the second doped layer, and the doped first semiconductor layer between the barrier layer and the substrate forms the first doped layer.

8. The preparation method according to claim 7, characterized in that: The first groove is formed in the barrier material layer by using laser patterning technology.

9. The preparation method according to claim 7, characterized in that: The first semiconductor layer is exposed at the bottom of the first trench. The second doped layer includes a first portion and a second portion. The doped first semiconductor layer at the bottom of the first trench forms the first portion, and the doped second semiconductor layer forms the second portion.

10. The preparation method according to claim 7, characterized in that: The second semiconductor layer and the first semiconductor layer are doped using a diffusion process.

11. A photovoltaic module, characterized in that: A solar cell comprising the solar cell according to any one of claims 1 to 5, and / or a solar cell manufactured by the method for manufacturing a solar cell according to any one of claims 6 to 10.

Images