Solar cell, method of manufacturing the same, and photovoltaic module

Abstract

The embodiment of the present disclosure relates to a solar cell, a preparation method thereof and a photovoltaic module. The solar cell comprises: a substrate comprising an adjacent metal contact region and a non-metal contact region; a first tunneling layer located on a first surface of the substrate and covering the metal contact region and the non-metal contact region; a first doped layer located on a surface of the first tunneling layer away from the substrate and covering the metal contact region and the non-metal contact region, the first doped layer comprising carbon elements and / or nitrogen elements; a second tunneling layer located on a surface of the first doped layer away from the substrate and covering the metal contact region; and a second doped layer located on a surface of the second tunneling layer away from the substrate and covering the metal contact region; wherein a doping concentration of a doped element of a first conductivity type in the second doped layer is greater than a doping concentration of the doped element of the first conductivity type in the first doped layer. The passivation effect of the first surface of the substrate is improved, the parasitic absorption of the first surface is reduced, and the conversion efficiency of the solar cell is improved.

Description

TECHNICAL FIELD

[0001] The embodiment of the present disclosure relates to the technical field of solar energy, in particular to a solar cell, a preparation method thereof and a photovoltaic module. BACKGROUND

[0002] A solar cell converts solar energy into electricity that can be directly used. The conversion efficiency of the solar cell determines the utilization efficiency of the solar energy. Improving the conversion efficiency of the solar cell has always been the focus of solar cell research. Parasitic absorption of carriers is an important factor affecting the conversion efficiency of the solar cell. SUMMARY

[0003] The embodiment of the present disclosure provides a solar cell, 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 comprises:

[0005] a substrate comprising an adjacent metal contact region and a non-metal contact region;

[0006] a first tunneling layer located on a first surface of the substrate and covering the metal contact region and the non-metal contact region;

[0007] a first doped layer located on a surface of the first tunneling layer away from the substrate and covering the metal contact region and the non-metal contact region, the first doped layer comprising carbon and / or nitrogen;

[0008] a second tunneling layer located on a surface of the first doped layer away from the substrate and covering the metal contact region;

[0009] a second doped layer located on a surface of the second tunneling layer away from the substrate and covering the metal contact region;

[0010] wherein the doping concentration of the first conductive type of the doping element in the second doped layer is greater than the doping concentration of the first conductive type of the doping element in the first doped layer.

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

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

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

[0014] In one of the embodiments, 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 region;

[0016] wherein opposite surfaces of the interface layer are adjacent to the second doped layer and the transparent conductive layer respectively.

[0017] In one of the embodiments, the first conductive type is N type, and the solar cell further comprises:

[0018] an intrinsic passivation layer located on a second surface of the substrate and covering the metal contact region and the non-metal contact region, the second surface being disposed opposite to the first surface;

[0019] a third doped layer located on a surface of the intrinsic passivation layer away from the substrate and covering the metal contact region and the non-metal contact region;

[0020] wherein the material of the third doped layer comprises P type microcrystalline silicon and / or P type amorphous silicon.

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

[0022] providing a substrate, the substrate comprising an adjacent metal contact region and a non-metal contact region;

[0023] forming a first tunneling layer on a first surface of the substrate, the first tunneling layer covering the metal contact region and the non-metal contact region;

[0024] forming a first doped layer on a surface of the first tunneling layer away from the substrate, the first doped layer containing carbon element and / or nitrogen element and covering the metal contact region and the non-metal contact region;

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

[0026] wherein the doping concentration of the doped element of the first conductive type in the second doped layer is greater than the doping concentration of the doped element of the first conductive type in the first doped layer.

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

[0028] forming a second tunneling material layer and a second doped material layer in sequence on a surface of the first doped layer away from the substrate, the second tunneling material layer and the second doped material layer both covering the metal contact region and the non-metal contact region.

[0029] performing a laser oxidation process on a surface layer of the second doped material layer of the metal contact region to form a doped oxide layer covering the metal contact region;

[0030] removing the second doped material layer of the non-metal contact region to form the second doped layer composed of the second doped material layer of the metal contact region with the doped oxide layer as a mask;

[0031] removing the second tunneling material layer of the non-metal contact region to form the second tunneling layer composed of the second tunneling material layer of the metal contact region.

[0032] In one of the embodiments, the method for manufacturing the solar cell further comprises:

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

[0034] forming a first electrode on a surface of the transparent conductive layer away from the substrate, the first electrode being adjacent to the transparent conductive layer, and a projection of the first electrode on the substrate being located in the metal contact region.

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

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

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

[0038] In one of the embodiments, the first conductive type is N-type, and the method for manufacturing the solar cell further comprises:

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

[0040] forming a third doped layer on a surface of the intrinsic passivation layer away from the substrate, the third doped layer covering the metal contact region and the non-metal contact region;

[0041] wherein, a material of the third doped layer comprises P-type microcrystalline silicon and / or P-type amorphous silicon.

[0042] A photovoltaic module comprising a plurality of the solar cells as described above, and / or comprising a plurality of the solar cells made by the method for making the solar cells as described above.

[0043] In the solar cell, the first doped layer containing carbon element and / or nitrogen element covers the metal contact region and the non-metal contact region, improves the passivation effect of the first surface of the substrate, increases the optical band gap, reduces the parasitic absorption of the first surface, and improves the conversion efficiency of the solar cell. The second doped layer on the first doped layer and having a doping concentration greater than that of the first doped layer covers the metal contact region, reduces the series resistance in the solar cell, and improves the performance of the solar cell.

[0044] In the method for making the solar cell, the first doped layer containing carbon element and / or nitrogen element formed on the first surface covers the metal contact region and the non-metal contact region, improves the passivation effect of the first surface of the substrate, increases the optical band gap, reduces the parasitic absorption of the first surface, and improves the conversion efficiency of the solar cell. The second doped layer on the first doped layer and having a doping concentration greater than that of the first doped layer covers the metal contact region, reduces the series resistance in the solar cell, and improves the performance of the solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the related art, hereinafter, a brief introduction will be given to the drawings needed to be used in the embodiments or related art descriptions. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0046] Figure 1 A flowchart of the method for making the solar cell in some embodiments;

[0047] Figure 2 A cross-sectional view of the solar cell after forming the second doped layer in some embodiments;

[0048] Figure 3 A cross-sectional view of the solar cell after forming the second doped layer in some embodiments;

[0049] Figure 4 A cross-sectional view of the solar cell after forming the doped oxide layer in some embodiments;

[0050] Figure 5 A cross-sectional view of the solar cell after forming the second doped layer in some embodiments;

[0051] Figure 6 A cross-sectional view of the solar cell after forming the transparent conductive layer in some embodiments;

[0052] Figure 7 FIG. 1 is a schematic diagram of a cross-section of a solar cell after forming a first electrode in some embodiments.

[0053] Legend of reference signs:

[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 the understanding of the embodiments of the present disclosure, the embodiments of the present disclosure will be described in more detail below with reference to the relevant drawings. The preferred 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 commonly understood by one of ordinary skill in the art to which the embodiments of the present disclosure belong. The terminology used in the description of the embodiments of the present disclosure herein is only for the purpose of describing the specific embodiments of the present disclosure, and is not intended to limit the embodiments of the present disclosure. The term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0057] In the description of the embodiments of the present disclosure, it should be understood that the terms "upper", "lower", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship based on the method or position shown in the drawings, and are only for the purpose of facilitating the description of the embodiments of the present disclosure and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present disclosure.

[0058] It can be understood that the terms "first", "second", and the like used in the present disclosure can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element. For example, without departing from the scope of the present disclosure, the first doped layer can be referred to as the second doped layer, and similarly, the second doped layer can be referred to as the 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", "second", etc. are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or an indicated number of technical features. Thus, features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly and specifically limited. In the description of the present disclosure, the meaning of "several" is at least one, such as one, two, etc., unless otherwise explicitly and specifically limited.

[0060] Figure 1 A flowchart of a method for preparing a solar cell in some embodiments, Figure 2 A cross-sectional view of a solar cell after forming a second doped layer in some embodiments, as shown in Figure 1 、 Figure 2 As shown in the figure, in the embodiment, a method for preparing a solar cell is provided, comprising:

[0061] S102, providing a substrate, the substrate comprising an adjacent metal contact region and a non-metal contact region.

[0062] A substrate 102 is provided, the substrate 102 comprising an adjacent metal contact region 1 and a non-metal contact region 2, the metal contact region 1 being a region on the substrate 102 for forming an electrode, the non-metal contact region 2 being a region on the substrate 102 except the metal contact region 2, and the adjacent means adjacent and in contact; the substrate 102 has a light-receiving surface and a back surface arranged opposite to each other, the light-receiving surface being a surface of the solar cell facing the sunlight (light-receiving surface), and the back surface being a surface of the substrate arranged opposite to the light-receiving surface, the substrate 102 comprising a semiconductor doped substrate made of silicon or germanium, a doped compound semiconductor substrate made of silicon carbide, silicon germanium, gallium arsenide, indium phosphide, zinc oxide or gallium oxide, etc. As an example, in the embodiment, the constituent material of the substrate 102 is selected as doped monocrystalline silicon.

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

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

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

[0066] The first doped layer 106 is formed on the first surface of the substrate 102 away from the first surface, the first doped layer 106 covers the metal contact region 1 and the non-metal contact region 2, and the first doped layer 106 contains carbon elements and / or nitrogen elements. The passivation effect of the first surface of the substrate 102 can be improved, the optical band gap is increased, the parasitic absorption of the first surface is reduced, and the conversion efficiency of the solar cell is improved through the first doped layer 106.

[0067] In S108, a second tunneling layer and a second doped layer are sequentially formed on the first doped layer away from the surface of the substrate, and the second tunneling layer and the second doped layer both cover the metal contact region.

[0068] The second tunneling layer 108 and the second doped layer 110 are sequentially formed on the first doped layer 106 away from the substrate 102, and the second tunneling layer 108 and the second doped layer 110 both cover the metal contact region 1. The doping concentration of the first conductive type doping element in the second doped layer 110 is greater than the doping concentration of the first conductive type doping element in the first doped layer 106. As an example, the material of the second tunneling layer 108 includes silicon dioxide. The second doped layer 110 covering the metal contact region 1 is located on the surface of the first doped layer 106 away from the substrate 102, and the doping concentration of the second doped layer 110 is greater than the doping concentration of the first doped layer 106, which reduces the series resistance in the solar cell and improves the performance of the solar cell. Moreover, the second tunneling layer 108 between the second doped layer 110 and the first doped layer 106 can avoid the influence of the second doped 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 conductive type is N-type or P-type. As an example, the N-type doping element includes one or more of phosphorus elements, arsenic elements and antimony elements, and the P-type doping element includes one or more of boron elements, aluminum elements, gallium elements and indium elements. As an example, in the present embodiment, the N-type doping element is doped with phosphorus elements, and the P-type doping element is doped with boron elements.

[0070] In the preparation method of the above solar cell, the first doped layer 106 containing carbon elements and / or nitrogen elements formed on the first surface covers the metal contact region 1 and the non-metal contact region 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. The second doped layer 110 with a doping concentration greater than that of the first doped layer 106 covers the metal contact region 1 on the first doped layer 106, 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 layer of the light-receiving surface and the back surface of the substrate 102 is removed. Again, the light-receiving surface and the back surface of the substrate 102 is treated with a texturing solution including a basic reagent and an additive to form a pyramid texture. Exemplarily, the basic reagent in the texturing solution includes one or both of sodium hydroxide and potassium hydroxide, the volume ratio of the basic reagent includes 0.5%-2%, the volume ratio of the additive in the texturing solution includes 0.5%-2%; the size of the pyramid structure of the pyramid texture in the direction perpendicular to the substrate 102 includes 1um-5um, the average reflectivity of the pyramid texture includes 10%-15%.

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

[0073] Again, a plasma-enhanced chemical vapor deposition process using a process gas including a doping source of the first conductivity type and ammonia and / or methane is used to form an in-situ doped first doped layer 106 on the surface of the first tunneling layer 104 away from the substrate 102, the first doped layer 106 covering the metal contact region 1 and the non-metal contact region 2, the process temperature of the plasma-enhanced chemical vapor deposition process including 400℃-550℃, the thickness of the first doped layer 106 in the direction perpendicular to the substrate 102 includes 10nm-20nm.

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

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

[0076] The second tunneling material layer 202 and the second doped material layer 204 are sequentially formed on the surface of the first doped layer 106 away from the substrate 102 by a deposition process, such as a plasma enhanced chemical vapor deposition process, and cover the metal contact region 1 and the non-metal contact region 2; wherein the second doped material layer 204 comprises a doped element of the first conductivity type, and the doping concentration of the doped element of the first conductivity type in the second doped material layer 204 is greater than the doping concentration of the doped element in the first doped layer 106.

[0077] For example, the thickness of the second tunneling material layer 202 in the direction perpendicular to the substrate 102 includes 0.5nm-1nm, and the in-situ doped second doped material layer 204 is formed on the surface of the second tunneling material layer 202 away from the substrate 102 by a plasma enhanced chemical vapor deposition process using a process gas comprising a doped source of the first conductivity type, the process temperature of the plasma enhanced chemical vapor deposition process includes 400℃-550℃, and the thickness of the second doped material layer 204 in the direction perpendicular to the substrate 102 includes 10nm-200nm.

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

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

[0080] Before step S204, the method for preparing a solar cell further comprises: first, removing the first tunneling layer 104, the first doped layer 106, the second tunneling material layer 202, the second doped material layer 204 and the first doped glass material plated around the second surface of the substrate 102, wherein the second surface and the first surface are oppositely arranged. The first doped layer 106 and the second doped material layer 204 are removed by using a mixed reagent comprising an alkaline reagent and an additive, the alkaline reagent comprises 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%. Second, remove the first doped glass material on the first surface of the substrate 102.

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

[0082] Further, a thickness of the doped oxide layer 206 in the direction perpendicular to the substrate 102 is greater than a thickness of the second tunneling material layer 202, which can avoid exposing a top surface of the second doped layer 110 covered by the doped oxide layer 206 in a subsequent etching process 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, removing the second doped material layer of the non-metal contact region to form the second doped layer composed of the second doped material layer of the metal contact region, with the doped oxide layer as a mask.

[0084] As shown in Figure 5 , the second doped material layer 204 of the non-metal contact region 2 is removed by using an etching process, such as a wet etching process, with the doped oxide layer 206 as a mask to form the second doped layer 110 composed of the second doped material layer 204 of the metal contact region 1. In the etching process, the doped oxide layer 206 protects the top surface of the second doped material layer 204 of the metal contact region 1 as the second doped layer 110 away from the substrate 102, and the second tunneling material layer 202 of the non-metal contact region 2 acts as an etching stop layer for etching to remove the second doped material layer 204 of the non-metal contact region 2.

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

[0086] S208, removing the second tunneling material layer of the non-metal contact region to form the second tunneling layer composed of the second tunneling material layer of the metal contact region.

[0087] As shown in Figure 6As shown, the second tunneling material layer 202 of the non-metallic contact region 2 is etched away to form a second tunneling layer 108 composed of the second tunneling material layer 202 of the metallic contact region 1, and the doped oxide layer 206 and the second doped layer 110 protect the metallic contact region 1 from the etching process. In the process of etching 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 the second tunneling material layer 202 of the non-metallic contact region 2 is etched away, the doped oxide layer 206 on the top surface of the second doped layer 110 is etched away.

[0088] In one embodiment, the material of the first doped layer 106 is amorphous silicon containing carbon and / or nitrogen, and the material of the second doped layer 110 is doped amorphous silicon. The method further comprises annealing the first doped layer 106 and the second doped layer 110 to convert the amorphous silicon containing carbon and / or nitrogen into polycrystalline silicon containing carbon and / or nitrogen, and convert the doped amorphous silicon into doped polycrystalline silicon. For example, the annealing process is performed at a temperature of 850-950°C, the first doped layer 106 has a doping concentration of 5E19-1E20 of the first conductive type, and the second doped layer 110 has a doping concentration of 5E20-1E21 of the first conductive type.

[0089] As shown in FIG. 1, in one embodiment, the method further comprises steps S302-S304. Figure 6

[0090] S302, forming a transparent conductive layer 112 on the surface of the second doped layer 110 away from the substrate 102, the transparent conductive layer 112 covering at least the metallic contact region 1.

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

[0092] S302-S304 specifically include forming a transparent conductive layer 112 on the surface of the second doped layer 110 away from the substrate 102, the transparent conductive layer 112 covering at least the metallic contact region 1, Figure 6 ​The 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, and its orthographic projection onto 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 contact between the first electrode 114 and the surface of the transparent conductive layer 112 can reduce contact resistance, prevent direct contact between the first electrode 114 and the substrate, reduce metal recombination, and reduce the thickness of the second doped layer 110, thereby reducing parasitic absorption and improving the performance of the solar cell. Exemplarily, the first electrode 114 is formed using a printing process, and the material of the first electrode 114 includes one or more combinations of aluminum, copper, gold, silver, and nickel.

[0093] Figure 7 This is a cross-sectional schematic diagram of the solar cell after the first electrode has been formed 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 fabricating the 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 region 1; wherein the opposing surfaces of the interface layer 116 are adjacent to the second doped layer 110 and the transparent conductive layer 112, respectively. The interface layer 116 can perform hydrogen passivation on the second doped layer 110, avoiding sputtering damage, and simultaneously achieve bandgap modulation to reduce contact resistance, increase the fill factor, and thus improve the performance of the solar cell.

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

[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 steps S402-S404.

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

[0097] Specifically, the intrinsic passivation layer 118 is formed on the second surface of the substrate 102 by a deposition process, the intrinsic passivation layer 118 covering the metal contact region 1 and the non-metal contact region 2, the second surface being opposite to the first surface. For example, the process temperature of the deposition process is 100-300°C, and the thickness of the intrinsic passivation layer 118 is 10-50nm. The material of the intrinsic passivation layer 118 includes at least one of intrinsic amorphous silicon, intrinsic polycrystalline silicon, intrinsic nanocrystalline silicon and intrinsic microcrystalline silicon.

[0098] S404, forming a third doped layer on the surface of the intrinsic passivation layer away from the substrate, the third doped layer covering the metal contact region and the non-metal contact region.

[0099] Specifically, the third doped layer 120 is formed on the surface of the intrinsic passivation layer 118 away from the substrate 102 by a deposition process, the third doped layer 120 covering the metal contact region 1 and the non-metal contact region 2; wherein the material of the third doped layer 120 includes P-type microcrystalline silicon and / or P-type amorphous silicon. For example, the process temperature of the deposition process is 100-300°C, and the thickness of the third doped layer 120 is 10-50nm. Compared with the P-type doped layer and the tunneling layer, the intrinsic passivation layer 118 and the third doped layer 120 including P-type microcrystalline silicon and / or P-type amorphous silicon are arranged on the second surface of the substrate 102, which can increase the doping concentration of the P-type doping element in the third doped layer 120, and the arrangement of the intrinsic passivation layer 118 can avoid the enrichment of the P-type doping element in the tunneling layer affecting the passivation effect, indirectly improving the passivation effect and improving the performance of the solar cell.

[0100] As Figure 7In some embodiments, the method for preparing a solar cell further comprises: forming a second transparent conductive layer 122 on the surface of the third doped layer 120 away from the substrate 102, the second transparent conductive layer 122 covering the metal contact regions 1 and the non-metal contact regions 2; and forming a second electrode 124 on the surface of the second transparent conductive layer 122 away from the substrate 102, the second electrode 124 being 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 being located in the metal contact regions 1, the other end of the solar cell being led out through the second electrode 124. The second electrode 124 is in contact with the surface of the second transparent conductive layer 122, which can reduce the contact resistance, and the thickness of the third doped layer 120 can be reduced, the parasitic absorption can be reduced, and the performance of the solar cell can be improved. The second electrode 124 is formed by a printing process, and the material of the second electrode 124 includes one or more than two combinations of aluminum, copper, gold, silver, and nickel.

[0101] It should be understood that, although Figure 1 the steps in the flowcharts are shown in sequence according to the arrows, the steps are not necessarily executed in sequence according to the arrows. Unless otherwise specified herein, the execution of the steps is not strictly limited in sequence, and the steps can be executed in other sequences. Moreover, Figure 1 at least part of the steps in the flowcharts can include multiple sub-steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of the sub-steps or stages is not necessarily sequential, but can be executed in rotation or alternation 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 same or corresponding parts of the embodiments of the method for preparing a solar cell described above will not be described herein. As Figure 2As shown in the embodiment, the solar cell comprises: a substrate 102, a first tunneling layer 104, a first doped layer 106, a second tunneling layer 108, and a second doped layer 110; the substrate 103 comprises an adjacent metal contact region 1 and a non-metal contact region 2; the first tunneling layer 104 is located on the first surface of the substrate 102 and covers the metal contact region 1 and the non-metal contact region 2; the first doped layer 106 is located on the surface of the first tunneling layer 104 away from the substrate 102 and covers the metal contact region 1 and the non-metal contact region 2, and the first doped layer 106 contains carbon and / or nitrogen elements; the second tunneling layer 108 is located on the surface of the first doped layer 106 away from the substrate 102 and covers the metal contact region 1; the second doped layer 110 is located on the surface of the second tunneling layer 108 away from the substrate 102 and covers the metal contact region 1; wherein the doping concentration of the first conductive type of the doping elements in the second doped layer 110 is greater than the doping concentration of the first conductive type of the doping elements in the first doped layer 106.

[0103] In the above-mentioned solar cell, the first doped layer 106 containing carbon and / or nitrogen elements covers the metal contact region 1 and the non-metal contact region 2, which improves the passivation effect of the first surface of the substrate 102, increases the optical band gap, reduces the parasitic absorption of the first surface, and improves the conversion efficiency of the solar cell. The second doped layer 110 with a doping concentration greater than that of the first doped layer 106 covers the metal contact region 1 on the first doped layer 106, which reduces the series resistance in the solar cell and improves the performance of the solar cell.

[0104] In one embodiment, the thickness of the second doped layer 110 is greater than the thickness of the first doped layer 106, and the thickness of the first tunneling layer 104 is greater than the thickness of the second tunneling layer 108 in the direction perpendicular to the substrate 102. This arrangement can reduce the risk of the first electrode penetrating the second doped layer 110, and the thickness of the first tunneling layer 104 being greater than the thickness of the second tunneling layer 108 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] As 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, at least covering the metal contact region 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 region 1. One end of the solar cell is led out through the first electrode 114. The contact between the first electrode 114 and the surface of the transparent conductive layer 112 can reduce 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, thereby reducing parasitic absorption and improving the performance of the solar cell.

[0106] like Figure 7 As shown, in one embodiment, the solar cell further includes an interface layer 116, which is located on the surface of the second doped layer 110 away from the substrate 102 and covers the metal contact region 1; wherein the opposing surfaces of the interface layer 116 are adjacent to the second doped layer 110 and the transparent conductive layer 112, respectively. The interface layer 116 can perform hydrogen passivation on the second doped layer 110 to avoid sputtering damage, while also enabling bandgap modulation to reduce contact resistance, increase the fill factor, and thus improve the performance of the solar cell.

[0107] In one embodiment, the material of the first doped layer 106 is polycrystalline silicon containing carbon and / or nitrogen of the first conductivity type, and the material of the second doped layer 110 includes doped polycrystalline silicon of the first conductivity type. The doping concentration of the doping element of the first conductivity type in the first doped layer 106 is 5E19-1E20; the doping concentration of the doping element of the first conductivity type in the second doped 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 doped layer 120; the intrinsic passivation layer 118 is located on the second surface of the substrate 102 and covers the metal contact region 1 and the non-metal contact region 2, the second surface being disposed opposite to the first surface; the third doped layer 120 is located on the surface of the intrinsic passivation layer 118 away from the substrate 102 and covers the metal contact region 1 and the non-metal contact region 2; wherein, the material of the third doped layer 120 includes P-type microcrystalline silicon and / or P-type amorphous silicon. Compared with setting a P-type doped layer and a tunneling layer, setting an intrinsic passivation layer 118 and a third doped 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 P-type dopants in the third doped layer 120. Furthermore, the setting of the intrinsic passivation layer 118 can prevent P-type dopants from accumulating in the tunneling layer and affecting the passivation effect, thereby indirectly improving the passivation effect and enhancing 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 region 1, through which one end of the solar cell is led out; 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 region 1 and the non-metal contact region 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 region 1, through which the other end of the solar cell is led out. The contact between the first electrode 114 and the surface of the transparent conductive layer 112 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 is in contact with the surface of the second transparent conductive layer 122, which can reduce the contact resistance and reduce the thickness of the third doped layer 120, thereby reducing parasitic absorption and improving the performance of the solar cell.

[0110] This disclosure also provides a photovoltaic module, including a plurality of solar cells as described above, and / or a plurality of solar cells made using the solar cell preparation method described above.

[0111] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, as long as there is no conflict, any combination of the technical features should be considered within the scope of the present disclosure.

[0112] The above-described embodiments only express several implementation manners of the present disclosure, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that, for ordinary skilled persons in the art, without departing from the concept of the present disclosure, several modifications and improvements can be made, which are within the protection scope of the present disclosure.

Claims

1. A solar cell, characterized by, The solar cell comprises: a substrate comprising an adjacent metal contact region and a non-metal contact region; a first tunneling layer located on a first surface of the substrate and covering the metal contact region and the non-metal contact region; a first doped layer located on a surface of the first tunneling layer away from the substrate and covering the metal contact region and the non-metal contact region, the first doped layer comprising carbon elements and / or nitrogen elements; a second tunneling layer located on a surface of the first doped layer away from the substrate and covering the metal contact region; a second doped layer located on a surface of the second tunneling layer away from the substrate and covering the metal contact region; a transparent conductive layer located on a surface of the second doped layer away from the substrate and covering at least the metal contact region; an interface layer located on a surface of the second doped layer away from the substrate and covering the metal contact region, for hydrogen passivation of the second doped layer; wherein a doping concentration of a first conductive type of doped elements in the second doped layer is greater than a doping concentration of the first conductive type of doped elements in the first doped layer; and opposite surfaces of the interface layer are adjacent to the second doped layer and the transparent conductive layer, respectively.

2. The solar cell according to claim 1, characterized in that, The solar cell further comprises: a first electrode located on a surface of the transparent conductive layer away from the substrate and adjacent to the transparent conductive layer, a projection of the first electrode on the substrate being located in the metal contact region.

3. The solar cell according to claim 1, characterized in that, In a direction perpendicular to the substrate, a thickness of the second doped layer is greater than a thickness of the first doped layer, and a thickness of the first tunneling layer is greater than a thickness of the second tunneling layer.

4. The solar cell of claim 1, wherein The first conductive type is N-type, and the solar cell further comprises: an intrinsic passivation layer located on a second surface of the substrate and covering the metal contact region and the non-metal contact region, the second surface being opposite to the first surface; a third doped layer located on a surface of the intrinsic passivation layer away from the substrate and covering the metal contact region and the non-metal contact region; wherein a material of the third doped layer comprises P-type microcrystalline silicon and / or P-type amorphous silicon.

5. A method for producing a solar cell, characterized by, The solar cell comprises: a substrate comprising an adjacent metal contact region and a non-metal contact region; a first tunneling layer formed on a first surface of the substrate, the first tunneling layer covering the metal contact region and the non-metal contact region; a first doped layer formed on a surface of the first tunneling layer away from the substrate, the first doped layer comprising carbon elements and / or nitrogen elements and covering the metal contact region and the non-metal contact region; a second tunneling layer and a second doped layer formed in sequence on a surface of the first doped layer away from the substrate, the second tunneling layer and the second doped layer both covering the metal contact region; a transparent conductive layer formed on a surface of the second doped layer away from the substrate, the transparent conductive layer covering at least the metal contact region; wherein a doping concentration of a first conductive type of doped elements in the second doped layer is greater than a doping concentration of the first conductive type of doped elements in the first doped layer; before the transparent conductive layer is formed on the surface of the second doped layer away from the substrate, the method further comprises: forming an interface layer on a surface of the second doped layer away from the substrate, the interface layer covering the metal contact region, for hydrogen passivation of the second doped layer; opposite surfaces of the interface layer being adjacent to the second doped layer and the transparent conductive layer, respectively.

6. The method of producing a solar cell according to claim 5, wherein forming a second tunneling layer and a second doped layer on a surface of the first doped layer away from the substrate, in sequence, comprises: forming a second tunneling material layer and a second doped material layer on a surface of the first doped layer away from the substrate, in sequence, the second tunneling material layer and the second doped material layer both covering the metal contact region and the non-metal contact region; performing laser oxidation treatment on a surface layer of the second doped material layer of 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 doped material layer of the non-metal contact region, to form the second doped layer composed of the second doped material layer of the metal contact region; removing the second tunneling material layer of the non-metal contact region, to form the second tunneling layer composed of the second tunneling material layer of the metal contact region.

7. The method of producing a solar cell according to claim 5, wherein The method for manufacturing the solar cell further comprises: forming a first electrode on a surface of the transparent conductive layer away from the substrate, the first electrode being adjacent to the transparent conductive layer, and a normal projection of the first electrode on the substrate being located in the metal contact region.

8. The method of producing a solar cell according to claim 5, wherein The interface layer is formed by an atomic layer deposition process.

9. The method of producing a solar cell according to claim 5, wherein The first conductive type is N-type, and the method for manufacturing the solar cell further comprises: forming an intrinsic passivation layer on a second surface of the substrate, the intrinsic passivation layer covering the metal contact region and the non-metal contact region, the second surface being arranged opposite to the first surface; forming a third doped layer on a surface of the intrinsic passivation layer away from the substrate, the third doped layer covering the metal contact region and the non-metal contact region; The material of the third doped layer comprises P-type microcrystalline silicon and / or P-type amorphous silicon.

10. A photovoltaic module, characterized by, The solar cell comprises a plurality of solar cells as claimed in any one of claims 1-4, and / or a plurality of solar cells manufactured by the method as claimed in any one of claims 5-9.

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