Solar cell, preparation method thereof and photovoltaic module

Abstract

The embodiment of the invention relates to a solar cell, a preparation method thereof and a photovoltaic module. The solar cell comprises a substrate comprising a metal contact region and a non-metal contact region which are adjacent to each other; the first tunneling layer is located on the first surface of the substrate and covers the metal contact region and the non-metal contact region; the first doping layer is located on the surface, far away from the substrate, of the first tunneling layer, covers the metal contact region and the non-metal contact region, and comprises a carbon element and / or a nitrogen element; the second tunneling layer is located on the surface, away from the substrate, of the first doping layer and covers the metal contact region; the second doping layer is located on the surface, away from the substrate, of the second tunneling layer and covers the metal contact region; wherein the doping concentration of the doping element of the first conduction type in the second doping layer is greater than that of the doping element of the first conduction type in the first doping layer. The passivation effect of the first surface of the substrate is improved, parasitic absorption of the first surface is reduced, and the conversion efficiency of the solar cell is improved.

Description

Technical Field

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

[0002] Solar cells convert solar energy into directly usable electrical energy. The conversion efficiency of solar cells determines the efficiency of solar energy utilization. Improving the conversion efficiency of solar cells has always been the focus of solar cell research. Parasitic absorption of carriers is an important factor affecting the conversion efficiency of solar cells. Summary of the invention

[0003] The embodiments of the present disclosure provide a solar cell and a preparation method thereof, and a photovoltaic module, which can optimize the passivation effect of the solar cell, reduce the parasitic absorption of the solar cell, and improve the conversion efficiency of the solar cell.

[0004] A solar cell, comprising:

[0005] A substrate, including adjacent metallic contact areas and non-metallic contact areas;

[0006] A first tunneling layer, located on the first surface of the substrate and covering the metal contact area and the non-metal contact area;

[0007] A first doping layer, located on a surface of the first tunneling layer away from the substrate and covering the metal contact area and the non-metal contact area, wherein the first doping layer contains carbon and / or nitrogen;

[0008] A second tunneling layer is located on a surface of the first doped layer away from the substrate and covers the metal contact area;

[0009] A second doping layer is located on a surface of the second tunneling layer away from the substrate and covers the metal contact area;

[0010] The doping concentration of the doping element of the first conductivity type in the second doping layer is greater than the doping concentration of the doping element of the first conductivity type in the first doping layer.

[0011] In one embodiment, the solar cell further comprises:

[0012] a transparent conductive layer, located on a surface of the second doped layer away from the substrate and at least covering the metal contact area;

[0013] The first electrode is located on a surface of the transparent conductive layer away from the substrate and is adjacent to the transparent conductive layer. The orthographic projection of the first electrode on the substrate is located in the metal contact area.

[0014] In one embodiment, the solar cell further comprises:

[0015] an interface layer, located on a surface of the second doped layer away from the substrate and covering the metal contact area;

[0016] Wherein, opposite surfaces of the interface layer are adjacent to the second doping layer and the transparent conductive layer respectively.

[0017] In one embodiment, the first conductivity type is N type, and the solar cell further comprises:

[0018] An intrinsic passivation layer is located on a second surface of the substrate and covers the metal contact area and the non-metal contact area, wherein the second surface is disposed opposite to the first surface;

[0019] A third doping layer is located on a surface of the intrinsic passivation layer away from the substrate and covers the metal contact area and the non-metal contact area;

[0020] Wherein, the material of the third doping layer includes P-type microcrystalline silicon and / or P-type amorphous silicon.

[0021] A method for preparing a solar cell, comprising:

[0022] providing a substrate comprising a contiguous metallic contact region and a non-metallic contact region;

[0023] Forming a first tunneling layer on the first surface of the substrate, wherein the first tunneling layer covers the metal contact area and the non-metal contact area;

[0024] forming a first doping layer on a surface of the first tunneling layer away from the substrate, wherein the first doping layer comprises carbon and / or nitrogen and covers the metal contact region and the non-metal contact region;

[0025] forming a second tunneling layer and a second doping layer in sequence on a surface of the first doping layer away from the substrate, wherein the second tunneling layer and the second doping layer both cover the metal contact region;

[0026] The doping concentration of the doping element of the first conductivity type in the second doping layer is greater than the doping concentration of the doping element of the first conductivity type in the first doping layer.

[0027] In one embodiment, the forming of a second tunneling layer and a second doping layer in sequence on a surface of the first doping layer away from the substrate comprises:

[0028] forming a second tunneling material layer and a second doping material layer in sequence on a surface of the first doping layer away from the substrate, wherein the second tunneling material layer and the second doping material layer both cover the metal contact area and the non-metal contact area;

[0029] Performing laser oxidation treatment on a surface layer of the second doping material layer in the metal contact region to form a doped oxide layer covering the metal contact region;

[0030] Using the doped oxide layer as a mask, removing the second doping material layer in the non-metal contact area to form the second doping layer composed of the second doping material layer in the metal contact area;

[0031] The second tunneling material layer in the non-metal contact area is removed to form the second tunneling layer composed of the second tunneling material layer in the metal contact area.

[0032] In one embodiment, the method for preparing a solar cell further comprises:

[0033] forming a transparent conductive layer on a surface of the second doped layer away from the substrate, wherein the transparent conductive layer at least covers the metal contact area;

[0034] A first electrode is formed on a surface of the transparent conductive layer away from the substrate. The first electrode is adjacent to the transparent conductive layer, and an orthographic projection of the first electrode on the substrate is located in the metal contact area.

[0035] In one embodiment, before forming the transparent conductive layer on the surface of the second doped layer away from the substrate, the method for preparing a solar cell further comprises:

[0036] forming an interface layer on a surface of the second doped layer away from the substrate, wherein the interface layer covers the metal contact area;

[0037] Wherein, opposite surfaces of the interface layer are adjacent to the second doping layer and the transparent conductive layer respectively.

[0038] In one embodiment, the first conductivity type is N type, and the method for preparing a solar cell further includes:

[0039] forming an intrinsic passivation layer on the second surface of the substrate, the intrinsic passivation layer covering the metal contact area and the non-metal contact area, the second surface being arranged opposite to the first surface;

[0040] forming a third doping layer on a surface of the intrinsic passivation layer away from the substrate, wherein the third doping layer covers the metal contact area and the non-metal contact area;

[0041] Wherein, the material of the third doping layer includes P-type microcrystalline silicon and / or P-type amorphous silicon.

[0042] 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.

[0043] In the above solar cell, the first doping layer containing carbon and / or nitrogen covers the metal contact area and the non-metal contact area, thereby improving the passivation effect of the first surface of the substrate, increasing the optical band gap, reducing the parasitic absorption of the first surface, and improving the conversion efficiency of the solar cell. On the first doping layer, the second doping layer with a doping concentration greater than the first doping layer covers the metal contact area, thereby reducing the series resistance in the solar cell and improving the performance of the solar cell.

[0044] In the above-mentioned method for preparing solar cells, a first doping layer containing carbon and / or nitrogen elements formed on the first surface covers the metal contact area and the non-metal contact area, thereby improving the passivation effect of the first surface of the substrate, increasing the optical band gap, reducing the parasitic absorption of the first surface, and improving the conversion efficiency of the solar cell. On the first doping layer, a second doping layer with a doping concentration greater than that of the first doping layer covers the metal contact area, thereby reducing the series resistance in the solar cell and improving the performance of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] 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.

[0046] Figure 1 is a schematic diagram of a process for preparing a solar cell in some embodiments;

[0047] Figure 2 is a schematic cross-sectional view of a solar cell after a second doping layer is formed in some embodiments;

[0048] Figure 3 is a schematic cross-sectional view of a solar cell after a second doping material layer is formed in some embodiments;

[0049] Figure 4 is a schematic cross-sectional view of a solar cell after a doped oxide layer is formed in some embodiments;

[0050] Figure 5 is a schematic cross-sectional view of a solar cell after a second doping layer is formed in some embodiments;

[0051] Figure 6 is a schematic cross-sectional view of a solar cell after a transparent conductive layer is formed in some embodiments;

[0052] Figure 7 Schematic cross-sectional view of a solar cell after forming a first electrode in some other embodiments.

[0053] Description of reference numerals:

[0054] Substrate 102, first tunneling layer 104, first doped layer 106, second tunneling layer 108, second doped layer 110, transparent conductive layer 112, first electrode 114, interface layer 116, intrinsic passivation layer 118, third doped layer 120, second transparent conductive layer 122, second electrode 124, second tunneling material layer 202, second doped material layer 204, doped oxide layer 206. DETAILED DESCRIPTION

[0055] 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.

[0056] 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.

[0057] In the description of the embodiments of the present disclosure, it should be understood that the terms "upper", "lower", "vertical", "horizontal", "inside", "outside", etc. indicating orientations or positional relationships are based on the methods or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present disclosure.

[0058] It is understood that the terms "first", "second", etc. used in the present disclosure may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of the present disclosure, 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. Both the first doped layer and the second doped layer are doped layers, but they are not the same doped layer.

[0059] 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.

[0060] 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 after forming a second doping layer in some embodiments, such as Figure 1 , Figure 2 As shown, in this embodiment, a method for preparing a solar cell is provided, comprising:

[0061] S102, providing a substrate, wherein the substrate includes adjacent metal contact areas and non-metal contact areas.

[0062] A substrate 102 is provided, the substrate 102 includes adjacent metal contact areas 1 and non-metal contact areas 2, the metal contact area 1 is an area on the substrate 102 where electrodes are formed, the non-metal contact area 2 is an area on the substrate 102 other than the metal contact area 2, and adjacent means adjacent and in contact; the substrate 102 has a light-receiving surface and a light-receiving surface that are disposed opposite to each other, the light-receiving surface is a surface of the solar cell that faces the sunlight (the light-facing surface), and the light-receiving surface is a surface on the substrate that is disposed opposite to the light-receiving surface, and the substrate 102 includes a semiconductor doped substrate made of silicon or germanium, etc., 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.

[0063] S104, forming a first tunneling layer on the first surface of the substrate, wherein the first tunneling layer covers the metal contact area and the non-metal contact area.

[0064] Specifically, a first tunneling layer 104 is formed on a first surface of the substrate 102, the first surface including a light-facing surface and / or a light-receiving surface of the substrate 102; the first tunneling layer 104 covers the metal contact area 1 and the non-metal contact area 2, and structure A covering structure B means that the projection of structure A on structure B overlaps with structure B. As an example, the material of the first tunneling layer 104 includes silicon dioxide.

[0065] S106, forming a first doping layer on a surface of the first tunneling layer away from the substrate, wherein the first doping layer includes carbon elements and / or nitrogen elements and covers the metal contact region and the non-metal contact region.

[0066] A first doping layer 106 is formed on the surface of the first tunneling layer 104 away from the substrate 102. The first doping layer 106 covers the metal contact area 1 and the non-metal contact area 2. The first doping layer 106 contains carbon elements and / or nitrogen elements. The first doping layer 106 can improve the passivation effect of the first surface of the substrate 102, increase the optical band gap, reduce the parasitic absorption of the first surface, and improve the conversion efficiency of the solar cell.

[0067] S108, forming a second tunneling layer and a second doping layer in sequence on a surface of the first doping layer away from the substrate, wherein the second tunneling layer and the second doping layer both cover the metal contact region.

[0068] The second tunneling layer 108 and the second doping layer 110 are sequentially formed on the first doping layer 106 away from the substrate 102, and both the second tunneling layer 108 and the second doping layer 110 cover the metal contact area 1; wherein the doping concentration of the doping element of the first conductivity type in the second doping layer 110 is greater than the doping concentration of the doping element of the first conductivity type in the first doping layer 106. As an example, the material of the second tunneling layer 108 includes silicon dioxide. The second doping layer 110 covering the metal contact area 1 is located on the surface of the first doping layer 106 away from the substrate 102, and the doping concentration of the second doping layer 110 is greater than the doping concentration of the first doping layer 106, which reduces the series resistance in the solar cell and improves the performance of the solar cell. In addition, the second tunneling layer 108 between the second doping layer 110 and the first doping layer 106 can avoid the influence of the second doping layer 110 on the passivation effect of the first tunneling layer 104, thereby improving the performance of the solar cell.

[0069] It can be understood that the first conductivity type is N-type or P-type, and exemplary, 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 selected from doped phosphorus, and the P-type doping element is selected from doped boron.

[0070] In the above-mentioned method for preparing a solar cell, a first doping layer 106 containing carbon and / or nitrogen elements formed on the first surface covers the metal contact area 1 and the non-metal contact area 2, thereby improving the passivation effect of the first surface of the substrate 102, increasing the optical band gap, reducing the parasitic absorption of the first surface, and improving the conversion efficiency of the solar cell. On the first doping layer 106, a second doping layer 110 having a doping concentration greater than that of the first doping layer 106 covers the metal contact area 1, thereby reducing the series resistance in the solar cell and improving the performance of the solar cell.

[0071] After providing the substrate 102, the damaged layers on the light-facing side and the backlight side of the substrate 102 are removed. Again, the light-facing side and the backlight side of the substrate 102 are treated with a texturing solution including an alkaline agent and an additive to form a pyramid velvet surface. Exemplarily, the alkaline agent in the texturing solution includes one or both of sodium hydroxide and potassium hydroxide, the volume ratio of the alkaline agent includes 0.5%-2%, and the volume ratio of the additive in the texturing solution includes 0.5%-2%; the size of the pyramid structure of the pyramid velvet surface in the direction perpendicular to the substrate 102 includes 1um-5um, and the average reflectivity of the pyramid velvet surface includes 10%-15%.

[0072] Then, a deposition process, such as plasma enhanced chemical vapor deposition process, is used to form a first tunneling layer 104 on the first surface of the substrate 102, and the first tunneling layer 104 covers the metal contact area 1 and the non-metal contact area 2. As an example, the thickness of the first tunneling layer 104 perpendicular to the substrate 102 includes 1nm-2nm.

[0073] Again, a plasma enhanced chemical vapor deposition process is used in which the process gas includes a doping source of the first conductive type and ammonia and / or methane, and an in-situ doped first doping layer 106 is formed on the surface of the first tunneling layer 104 away from the substrate 102. The first doping layer 106 covers the metal contact area 1 and the non-metallic contact area 2. The process temperature of the plasma enhanced chemical vapor deposition process includes 400°C-550°C, and the thickness of the first doping layer 106 in a direction perpendicular to the substrate 102 includes 10nm-20nm.

[0074] Figure 3 is a schematic cross-sectional view of a solar cell after a second doping material layer is formed in some embodiments, Figure 4 is a schematic cross-sectional view of a solar cell after a doped oxide layer is formed in some embodiments, Figure 5 is a schematic cross-sectional view of a solar cell after forming a second doping layer in some embodiments, Figure 6 is a schematic cross-sectional view of a solar cell after a transparent conductive layer is formed in some embodiments, such as Figure 3-6 As shown, in one embodiment, the second tunneling layer 108 and the second doping layer 110 are sequentially formed on the surface of the first doping layer 106 away from the substrate 102, including: steps S202-S208.

[0075] S202 , sequentially forming a second tunneling material layer and a second doping material layer on a surface of the first doping layer away from the substrate.

[0076] A deposition process, such as a plasma enhanced chemical vapor deposition process, is used to sequentially form a second tunneling material layer 202 and a second doping material layer 204 on a surface of the first doping layer 106 away from the substrate 102, wherein the second tunneling material layer 202 and the second doping material layer 204 both cover the metal contact area 1 and the non-metallic contact area 2; wherein the second doping material layer 204 includes a doping element of a first conductive type, and the doping concentration of the doping element of the first conductive type in the second doping material layer 204 is greater than the doping concentration of the doping element in the first doping layer 106.

[0077] Exemplarily, the thickness of the second tunneling material layer 202 in a direction perpendicular to the substrate 102 includes 0.5nm-1nm, and a plasma enhanced chemical vapor deposition process is used in which the process gas includes a doping source of the first conductive type, to form an in-situ doped second doping material layer 204 on the surface of the second tunneling material layer 202 away from the substrate 102. The process temperature of the plasma enhanced chemical vapor deposition process includes 400°C-550°C, and the thickness of the second doping material layer 204 in a direction perpendicular to the substrate 102 includes 10nm-200nm.

[0078] S204, performing laser oxidation treatment on the surface layer of the second doping material layer in the metal contact region to form a doped oxide layer covering the metal contact region.

[0079] Exemplarily, the material of the second doping material layer 204 includes doped amorphous silicon of the first conductivity type. In the process of forming the second doping material layer 204, a first doping glass material is formed on the surface of the second doping material layer 204 away from the substrate 102, and the first doping glass material covers the surface of the second doping material layer 204 away from the substrate 102. In the case where the doping element of the first conductivity type in the second doping material layer 204 is an N-type phosphorus element, the first doping glass material is phosphate glass. In the case where the doping element of the first conductivity type in the second doping material layer 204 is a P-type boron element, the first doping glass material is borate glass.

[0080] Before step S204, the method for preparing a solar cell further includes: first, removing the first tunneling layer 104, the first doping layer 106, the second tunneling material layer 202, the second doping material layer 204 and the first doped glass material that are plated around the second surface of the substrate 102, wherein the second surface and the first surface are arranged opposite to each other. Using a mixed reagent including an alkaline reagent and an additive to remove the first doping layer 106 and the second doping material layer 204, the alkaline reagent includes one or more of KOH, NaOH or TMAH, the volume ratio of the alkaline reagent in the mixed reagent includes 1%-4%, and the volume ratio of the additive in the mixed reagent includes 0.5%-1.5%. Secondly, removing the first doped glass material on the first surface of the substrate 102.

[0081] like Figure 3 , Figure 4 As shown, step S204 specifically comprises: performing laser oxidation treatment on the surface layer of the second doping material layer 204 of the metal contact area 1 to form a doped oxide layer 206; the surface layer of the second doping material layer 204 of the metal contact area 1 is the portion of the second doping material layer 204 of the metal contact area 1 away from the substrate 102, the surface layer of the second doping material layer 204 of the metal contact area 1 covers the metal contact area 1, and in a direction perpendicular to the substrate 102, the doped oxide layer 206 is close to the bottom surface of the substrate 102 and there is a second doping material layer 204 between the substrate 102.

[0082] Furthermore, the thickness of the doped oxide layer 206 in the direction perpendicular to the substrate 102 is greater than the thickness of the second tunneling material layer 202, which can prevent the top surface of the second doped layer 110 covered by the doped oxide layer 206 from being exposed during the subsequent etching of the second tunneling material layer 202. Exemplarily, the thickness of the doped oxide layer 206 in the direction perpendicular to the substrate 102 includes 3nm-8nm.

[0083] S206, using the doped oxide layer as a mask, removing the second doping material layer in the non-metal contact area to form the second doping layer composed of the second doping material layer in the metal contact area.

[0084] like Figure 5 As shown, the doped oxide layer 206 is used as a mask and an etching process, such as a wet etching process, is used to remove the second doping material layer 204 of the non-metallic contact area 2, so as to form the second doping layer 110 composed of the second doping material layer 204 of the metal contact area 1. In the etching process, the doped oxide layer 206 protects the second doping material layer 204 of the metal contact area 1 as the second doping layer 110 away from the top surface of the substrate 102, and the second tunneling material layer 202 of the non-metallic contact area 2 is used as an etching stop layer for etching and removing the second doping material layer 204 of the non-metallic contact area 2.

[0085] Exemplarily, the etching solution of the wet etching process for etching the second doping material layer 204 includes an alkaline agent and an additive, wherein the alkaline agent includes one or both of sodium hydroxide and potassium hydroxide, the volume ratio of the alkaline agent includes 0.5%-2%, and the volume ratio of the additive includes 0.5%-2%.

[0086] S208 , removing the second tunneling material layer in the non-metal contact area, and forming the second tunneling layer composed of the second tunneling material layer in the metal contact area.

[0087] like Figure 6As shown, the second tunneling material layer 202 of the non-metallic contact region 2 is etched away using the doped oxide layer 206 and the second doped layer 110 as masks to form a second tunneling layer 108 composed of the second tunneling material layer 202 of the metal contact region 1. In the process of etching away the second tunneling material layer 202 of the non-metallic contact region 2, the doped oxide layer 206 and the second doped layer 110 protect the second doped material layer 204 of the metal contact region 1 as the second doped layer 110 away from the top surface of the substrate 102 to avoid etching damage to the second doped material layer 204 as the second doped layer 110. It can be understood that in the process of removing the second tunneling material layer 202 of the non-metallic contact region 2, the doped oxide layer 206 on the top surface of the second doped layer 110 is etched away; or after removing the second tunneling material layer 202 of the non-metallic contact region 2, the doped oxide layer 206 as the protective layer on the top surface of the second doped layer 110 is etched away.

[0088] In one embodiment, the material of the first doping layer 106 is amorphous silicon including carbon and / or nitrogen, and the material of the second doping layer 110 is doped amorphous silicon. The method for preparing a solar cell further includes: annealing the first doping layer 106 and the second doping layer 110 to convert the amorphous silicon including carbon and / or nitrogen into polycrystalline silicon including carbon and / or nitrogen, and convert the doped amorphous silicon into doped polycrystalline silicon. Exemplarily, the annealing process temperature includes 850°C-950°C, the doping concentration of the first conductivity type doping element in the first doping layer 106 is 5E19-1E20; the doping concentration of the first conductivity type doping element in the second doping layer 110 is 5E20-1E21.

[0089] like Figure 6 As shown, in one of the embodiments, the method for preparing a solar cell further includes steps S302-S304.

[0090] S302 , forming a transparent conductive layer 112 on a surface of the second doping layer 110 away from the substrate 102 , wherein the transparent conductive layer 112 at least covers the metal contact region 1 .

[0091] S304 , forming a first electrode 114 on a surface of the transparent conductive layer 112 away from the substrate 102 , wherein the first electrode 114 is adjacent to the transparent conductive layer 112 , and an orthographic projection of the first electrode 114 on the substrate 102 is located in the metal contact region 1 .

[0092] Steps S302-S304 are specifically to form a transparent conductive layer 112 on the surface of the second doping layer 110 away from the substrate 102, wherein the transparent conductive layer 112 at least covers the metal contact area 1. Figure 6The transparent conductive layer 112 shown covers the metal contact area 1 and the non-metal contact area 2. In other embodiments, the transparent conductive layer 112 covers the metal contact area 1 and exposes the non-metal contact area 2. Then, a first electrode 114 is formed on the surface of the transparent conductive layer 112 away from the substrate 102. The first electrode 114 is adjacent to the surface of the transparent conductive layer 112 away from the substrate 102. The orthographic projection of the first electrode 114 on the substrate 102 is located at the metal contact area 1, and one end of the solar cell is led out through the first electrode 114. The first electrode 114 contacts the surface of the transparent conductive layer 112, which can reduce the contact resistance, avoid direct contact between the first electrode 114 and the substrate, reduce metal recombination, and reduce the thickness of the second doping layer 110, reduce parasitic absorption, and improve the performance of the solar cell. Exemplarily, the first electrode 114 is formed by a printing process, and the material of the first electrode 114 includes one or a combination of more than two of aluminum, copper, gold, silver, and nickel.

[0093] Figure 7 is a cross-sectional schematic diagram of a solar cell after forming a first electrode in some other embodiments, such as Figure 7 As shown, in one embodiment, before forming the transparent conductive layer 112 on the surface of the second doped layer 110 away from the substrate 102, the method for preparing a solar cell further includes: forming an interface layer 116 on the surface of the second doped layer 110 away from the substrate 102, the interface layer 116 covering the metal contact area 1; wherein the opposite surfaces of the interface layer 116 are respectively adjacent to the second doped layer 110 and the transparent conductive layer 112. The interface layer 116 can be used to hydrogen passivate the second doped layer 110 to avoid sputtering damage, and can also achieve band control to reduce contact resistance, improve fill factor, and thus improve the performance of the solar cell.

[0094] Exemplarily, the interface layer 116 is formed by an atomic layer deposition process, the temperature of the atomic layer deposition process includes 100° C.-250° C., and the thickness of the interface layer 116 in the direction perpendicular to the substrate 102 includes 0.5 nm-10 nm. Exemplarily, the material of the interface layer 116 includes at least one of AlOx, AlxZnyO, AlOx / ZnO, and ZnO / AlOx. In the case where the interface layer 116 includes AlxZnyO, Zn doped in the middle of AlOx will reduce the work function, and the work function of the interface layer 116 can be adjusted by adjusting the ratio of Al and Zn, for example, the work function of the interface layer 116 includes 3.5eV-5.1eV.

[0095] like Figure 7 As shown, in one embodiment, the first conductivity type is N type, and the method for preparing the solar cell further includes: step S402 to step S404.

[0096] S402 , forming an intrinsic passivation layer 118 on the second surface of the substrate 102 , wherein the intrinsic passivation layer 118 covers the metal contact area 1 and the non-metal contact area 2 .

[0097] Specifically, a deposition process is used to form an intrinsic passivation layer 118 on the second surface of the substrate 102, the intrinsic passivation layer 118 covers the metal contact area 1 and the non-metal contact area 2, and the second surface is arranged opposite to the first surface. Exemplarily, the process temperature of the deposition process includes 100° C.-300° C., and the thickness of the intrinsic passivation layer 118 includes 10nm-50nm. The material of the intrinsic passivation layer 118 includes at least one of intrinsic amorphous silicon, intrinsic polycrystalline silicon, intrinsic nano-amorphous silicon and intrinsic microcrystalline silicon.

[0098] S404, forming a third doping layer on a surface of the intrinsic passivation layer away from the substrate, wherein the third doping layer covers the metal contact area and the non-metal contact area.

[0099] Specifically, a deposition process is adopted to form an in-situ doped third doping layer 120 on the surface of the intrinsic passivation layer 118 away from the substrate 102, and the third doping layer 120 covers the metal contact area 1 and the non-metal contact area 2; wherein the material of the third doping layer 120 includes P-type microcrystalline silicon and / or P-type amorphous silicon. Exemplarily, the process temperature of the deposition process includes 100°C-300°C, and the thickness of the third doping layer 120 includes 10nm-50nm. Compared with setting a P-type doping layer and a tunneling layer, setting an intrinsic passivation layer 118 and a third doping layer 120 including P-type microcrystalline silicon and / or P-type amorphous silicon P-type on the second surface of the substrate 102 can increase the doping concentration of the P-type doping element in the third doping layer 120, and the setting of the intrinsic passivation layer 118 can avoid the enrichment of the P-type doping element in the tunneling layer to affect the passivation effect, indirectly improving the passivation effect and improving the performance of the solar cell.

[0100] like Figure 7As shown, in some embodiments, the method for preparing a solar cell further includes: forming a second transparent conductive layer 122 on the surface of the third doping layer 120 away from the substrate 102, the second transparent conductive layer 122 covering the metal contact area 1 and the non-metal contact area 2; forming a second electrode 124 on the surface of the second transparent conductive layer 122 away from the substrate 102, the second electrode 124 is adjacent to the surface of the second transparent conductive layer 122 away from the substrate 102, and the orthographic projection of the second electrode 124 on the substrate 102 is located in the metal contact area 1, and the other end of the solar cell is led out through the second electrode 124. The second electrode 124 contacts the surface of the second transparent conductive layer 122, which can reduce the contact resistance, and can reduce the thickness of the third doping layer 120, reduce parasitic absorption, and improve the performance of the solar cell. Exemplarily, the second electrode 124 is formed by a printing process, and the material of the second electrode 124 includes one or a combination of more than two of aluminum, copper, gold, silver, and nickel.

[0101] 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 1 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed 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 part of the sub-steps or stages of other steps.

[0102] The present disclosure 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 2As shown, in this embodiment, the solar cell includes: a substrate 102, a first tunneling layer 104, a first doping layer 106, a second tunneling layer 108 and a second doping layer 110; the substrate 103 includes adjacent metal contact areas 1 and non-metal contact areas 2; the first tunneling layer 104 is located on the first surface of the substrate 102 and covers the metal contact areas 1 and the non-metal contact areas 2; the first doping layer 106 is located on the surface of the first tunneling layer 104 away from the substrate 102 and covers the metal contact areas 1 and the non-metal contact areas 2, and the first doping layer 106 contains carbon elements and / or nitrogen elements; the second tunneling layer 108 is located on the surface of the first doping layer 106 away from the substrate 102 and covers the metal contact area 1; the second doping layer 110 is located on the surface of the second tunneling layer 108 away from the substrate 102 and covers the metal contact area 1; wherein the doping concentration of the first conductive type doping element in the second doping layer 110 is greater than the doping concentration of the first conductive type doping element in the first doping layer 106.

[0103] In the above solar cell, the first doping layer 106 containing carbon and / or nitrogen covers the metal contact area 1 and the non-metal contact area 2, thereby improving the passivation effect of the first surface of the substrate 102, increasing the optical band gap, reducing the parasitic absorption of the first surface, and improving the conversion efficiency of the solar cell. On the first doping layer 106, the second doping layer 110 with a doping concentration greater than that of the first doping layer 106 covers the metal contact area 1, thereby reducing the series resistance in the solar cell and improving the performance of the solar cell.

[0104] In one embodiment, in a direction perpendicular to the substrate 102, the thickness of the second doping layer 110 is greater than the thickness of the first doping layer 106, and the thickness of the first tunneling layer 104 is greater than the thickness of the second tunneling layer 108. This configuration can reduce the risk of the first electrode passing through the second doping layer 110, and the thickness of the first tunneling layer 104 is greater than the thickness of the second tunneling layer 108, which can reduce the influence of the second tunneling layer 108 on the series resistance and the fill factor, thereby improving the conversion efficiency of the solar cell.

[0105] like Figure 6As shown, in one embodiment, the solar cell further includes: a transparent conductive layer 112 and a first electrode 114; the transparent conductive layer 112 is located on the surface of the second doped layer 110 away from the substrate 102, and at least covers the metal contact area 1; the first electrode 114 is located on the surface of the transparent conductive layer 112 away from the substrate 102, and is adjacent to the transparent conductive layer 112, and the orthographic projection of the first electrode 114 on the substrate 102 is located in the metal contact area 1. One end of the solar cell is led out through the first electrode 114. The first electrode 114 contacts the surface of the transparent conductive layer 112, which can reduce the contact resistance, avoid direct contact between the first electrode 114 and the substrate, reduce metal recombination, and reduce the thickness of the second doped layer 110, reduce parasitic absorption, and improve the performance of the solar cell.

[0106] like Figure 7 As shown, in one embodiment, the solar cell further includes: an interface layer 116, the interface layer 116 is located on the surface of the second doped layer 110 away from the substrate 102, and covers the metal contact area 1; wherein the opposite surfaces of the interface layer 116 are respectively adjacent to the second doped layer 110 and the transparent conductive layer 112. The interface layer 116 can be used to hydrogen passivate the second doped layer 110 to avoid sputtering damage, and at the same time, band regulation can be achieved to reduce contact resistance, improve fill factor, and thus improve the performance of the solar cell.

[0107] In one embodiment, the material of the first doping layer 106 is polycrystalline silicon of the first conductivity type containing carbon elements and / or nitrogen elements, the material of the second doping layer 110 includes doped polycrystalline silicon of the first conductivity type, and the doping concentration of the doping element of the first conductivity type in the first doping layer 106 is 5E19-1E20; the doping concentration of the doping element of the first conductivity type in the second doping layer 108 is 5E20-1E21.

[0108] like Figure 7As shown, in one embodiment, the first conductivity type is N-type, and the solar cell further includes: an intrinsic passivation layer 118 and a third doping layer 120; the intrinsic passivation layer 118 is located on the second surface of the substrate 102, and covers the metal contact area 1 and the non-metal contact area 2, and the second surface is arranged opposite to the first surface; the third doping layer 120 is located on the surface of the intrinsic passivation layer 118 away from the substrate 102, and covers the metal contact area 1 and the non-metal contact area 2; wherein the material of the third doping layer 120 includes P-type microcrystalline silicon and / or P-type amorphous silicon. Compared with setting a P-type doping layer and a tunneling layer, setting an intrinsic passivation layer 118 and a third doping layer 120 including P-type microcrystalline silicon and / or P-type amorphous silicon on the second surface of the substrate 102 can increase the doping concentration of the P-type doping element in the third doping layer 120, and the setting of the intrinsic passivation layer 118 can avoid the enrichment of the P-type doping element in the tunneling layer to affect the passivation effect, thereby indirectly improving the passivation effect and improving the performance of the solar cell.

[0109] like Figure 7 As shown, in one embodiment, the solar cell further includes: a first electrode 114, a second transparent conductive layer 122, and a second electrode 124; the first electrode 114 is located on the surface of the transparent conductive layer 112 away from the substrate 102, the first electrode 114 is adjacent to the surface of the transparent conductive layer 112 away from the substrate 102, and the projection of the first electrode 114 on the substrate 102 is located in the metal contact area 1, and one end of the solar cell is led out through the first electrode 114; the second transparent conductive layer 122 is located on the surface of the third doped layer 120 away from the substrate 102, covering the metal contact area 1 and the non-metal contact area 2; the second electrode 124 is located on the surface of the second transparent conductive layer 122 away from the substrate 102, and the projection of the second electrode 124 on the substrate 102 is located in the metal contact area 1, and the other end of the solar cell is led out through the second electrode 124. The first electrode 114 contacts the surface of the transparent conductive layer 112, which can reduce the contact resistance, and can reduce the thickness of the second doped layer 110, reduce parasitic absorption, and improve the performance of the solar cell. The second electrode 124 contacts the surface of the second transparent conductive layer 122 , which can reduce the contact resistance and reduce the thickness of the third doping layer 120 , thereby reducing parasitic absorption and improving the performance of the solar cell.

[0110] 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.

[0111] 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.

[0112] 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: A substrate, including adjacent metallic contact areas and non-metallic contact areas; A first tunneling layer, located on the first surface of the substrate and covering the metal contact area and the non-metal contact area; A first doping layer, located on a surface of the first tunneling layer away from the substrate and covering the metal contact area and the non-metal contact area, wherein the first doping layer contains carbon and / or nitrogen; A second tunneling layer is located on a surface of the first doped layer away from the substrate and covers the metal contact area; A second doping layer is located on a surface of the second tunneling layer away from the substrate and covers the metal contact area; The doping concentration of the doping element of the first conductivity type in the second doping layer is greater than the doping concentration of the doping element of the first conductivity type in the first doping layer.

2. The solar cell according to claim 1, characterized in that: Solar cells also include: a transparent conductive layer, located on a surface of the second doped layer away from the substrate and at least covering the metal contact area; The first electrode is located on a surface of the transparent conductive layer away from the substrate and is adjacent to the transparent conductive layer. The orthographic projection of the first electrode on the substrate is located in the metal contact area.

3. The solar cell according to claim 2, characterized in that: Solar cells also include: an interface layer, located on a surface of the second doped layer away from the substrate and covering the metal contact area; Wherein, opposite surfaces of the interface layer are adjacent to the second doping layer and the transparent conductive layer respectively.

4. The solar cell according to claim 1, characterized in that The first conductivity type is N type, and the solar cell further comprises: An intrinsic passivation layer is located on a second surface of the substrate and covers the metal contact area and the non-metal contact area, wherein the second surface is disposed opposite to the first surface; A third doping layer is located on a surface of the intrinsic passivation layer away from the substrate and covers the metal contact area and the non-metal contact area; Wherein, the material of the third doping layer includes P-type microcrystalline silicon and / or P-type amorphous silicon.

5. A method for preparing a solar cell, characterized in that: include: providing a substrate comprising a contiguous metallic contact region and a non-metallic contact region; Forming a first tunneling layer on the first surface of the substrate, wherein the first tunneling layer covers the metal contact area and the non-metal contact area; forming a first doping layer on a surface of the first tunneling layer away from the substrate, wherein the first doping layer comprises carbon and / or nitrogen and covers the metal contact region and the non-metal contact region; forming a second tunneling layer and a second doping layer in sequence on a surface of the first doping layer away from the substrate, wherein the second tunneling layer and the second doping layer both cover the metal contact region; The doping concentration of the doping element of the first conductivity type in the second doping layer is greater than the doping concentration of the doping element of the first conductivity type in the first doping layer.

6. The method for preparing a solar cell according to claim 5, characterized in that: The second tunneling layer and the second doping layer are sequentially formed on a surface of the first doping layer away from the substrate, comprising: forming a second tunneling material layer and a second doping material layer in sequence on a surface of the first doping layer away from the substrate, wherein the second tunneling material layer and the second doping material layer both cover the metal contact area and the non-metal contact area; Performing laser oxidation treatment on a surface layer of the second doping material layer in the metal contact region to form a doped oxide layer covering the metal contact region; Using the doped oxide layer as a mask, removing the second doping material layer in the non-metal contact area to form the second doping layer composed of the second doping material layer in the metal contact area; The second tunneling material layer in the non-metal contact area is removed to form the second tunneling layer composed of the second tunneling material layer in the metal contact area.

7. The method for preparing a solar cell according to claim 5, characterized in that: The method for preparing the solar cell further comprises: forming a transparent conductive layer on a surface of the second doped layer away from the substrate, wherein the transparent conductive layer at least covers the metal contact area; A first electrode is formed on a surface of the transparent conductive layer away from the substrate. The first electrode is adjacent to the transparent conductive layer, and an orthographic projection of the first electrode on the substrate is located in the metal contact area.

8. The method for preparing a solar cell according to claim 7, characterized in that: Before forming the transparent conductive layer on the surface of the second doped layer away from the substrate, the method for preparing a solar cell further comprises: forming an interface layer on a surface of the second doped layer away from the substrate, wherein the interface layer covers the metal contact area; Wherein, opposite surfaces of the interface layer are adjacent to the second doping layer and the transparent conductive layer respectively.

9. The method for preparing a solar cell according to claim 5, characterized in that: The first conductivity type is N type, and the method for preparing the solar cell further includes: forming an intrinsic passivation layer on the second surface of the substrate, the intrinsic passivation layer covering the metal contact area and the non-metal contact area, the second surface being arranged opposite to the first surface; forming a third doping layer on a surface of the intrinsic passivation layer away from the substrate, wherein the third doping layer covers the metal contact area and the non-metal contact area; Wherein, the material of the third doping layer includes P-type microcrystalline silicon and / or P-type amorphous silicon.

10. A photovoltaic module, characterized in that: The invention comprises a plurality of solar cells according to any one of claims 1 to 4, and / or a plurality of solar cells manufactured by the method for manufacturing a solar cell according to any one of claims 5 to 9.

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