Solar cell and manufacturing method thereof, laminated cell and photovoltaic module

Abstract

The invention relates to a solar cell and a manufacturing method thereof, a laminated cell and a photovoltaic module, and the solar cell comprises a substrate which is provided with a first surface and a second surface, the first tunneling layer is located on one side of the second surface; the first doped semiconductor layer is located on the side, away from the substrate, of the first tunneling layer; wherein the first doped semiconductor layer is doped with a boron element and a gallium element, and in the direction from the first surface to the second surface, the doping concentration of the boron element is gradually reduced, and the doping concentration of the gallium element is gradually increased. The performance of the solar cell can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cell manufacturing, and in particular to a solar cell, a manufacturing method thereof, a stacked cell and a photovoltaic module. BACKGROUND

[0002] Solar energy, as a new energy, has various advantages such as inexhaustibility, cleanness and environmental protection compared with traditional fossil fuels. At present, a main way of solar energy utilization is to convert received light energy into electric energy output through a solar cell module, which can be a large-area cell module formed by packaging and arranging in a square matrix after series connection of a plurality of solar cells (or photovoltaic cells, or photovoltaic modules). Among them, the solar cell absorbs light energy, and accumulation of hetero-charges occurs at both ends of the cell, that is, a "photovoltaic effect" is generated. Under the action of the photovoltaic effect, an electromotive force is generated at both ends of the solar cell, so as to convert light energy into electric energy.

[0003] However, the performance of the solar cell still needs to be further improved. SUMMARY

[0004] Therefore, it is necessary to provide a solar cell, a manufacturing method thereof and a photovoltaic module aiming at the problem of how to improve the performance of the solar cell.

[0005] In a first aspect, the present application provides a solar cell, comprising:

[0006] a substrate having a first surface and a second surface arranged oppositely;

[0007] a first tunneling layer located on one side of the second surface;

[0008] a first doped semiconductor layer located on a side of the first tunneling layer away from the substrate;

[0009] wherein the first doped semiconductor layer is doped with boron elements and gallium elements, and in a direction in which the first surface points to the second surface, the doping concentration of the boron elements gradually decreases, and the doping concentration of the gallium elements gradually increases.

[0010] In some embodiments, the first doped semiconductor layer has a first sub-surface part close to the first surface, and a second sub-surface part away from the first surface;

[0011] In the first sub-surface part, the doping concentration of the boron elements is greater than the doping concentration of the gallium elements;

[0012] In the second sub-surface part, the doping concentration of the boron elements is greater than the doping concentration of the gallium elements.

[0013] In some embodiments, in the first doped semiconductor layer, the doping concentration of the boron element is 1×10 20 cm -3 -5×10 19 cm -3 .

[0014] In some embodiments, in the first doped semiconductor layer, the doping concentration of the gallium element is 1×10 18 cm -3 -1×10 19 cm -3 .

[0015] In some embodiments, in the first sub-surface portion, the doping concentration of the boron element is 0.7×10 20 cm -3 -1.5×10 20 cm -3 ; and / or,

[0016] In the first sub-surface portion, the doping concentration of the gallium element is 0.5×10 18 cm -3 -3×10 18 cm -3 .

[0017] In some embodiments, in the second sub-surface portion, the doping concentration of the boron element is 3×10 19 cm -3 -8×10 19 cm -3 ; and / or,

[0018] In the second sub-surface portion, the doping concentration of the gallium element is 0.7×10 19 cm -3 -2×10 19 cm -3 .

[0019] In some embodiments, the material of the first tunneling layer comprises silicon oxide, and the material of the first doped semiconductor layer comprises polysilicon; and / or,

[0020] The thickness of the first tunneling layer is 1-2 nm, and the thickness of the first doped semiconductor layer is 50-150 nm.

[0021] In some embodiments, the first doped semiconductor layer is further doped with hydrogen element, and the doping concentration of the hydrogen element is 1×10 19 cm -3 -1×10 20 cm -3 .

[0022] In a second aspect, based on the same inventive concept, the present application further provides a method for manufacturing a solar cell, comprising:

[0023] providing a substrate, the substrate having a first surface and a second surface oppositely arranged;

[0024] forming a first tunneling layer on the second surface;

[0025] forming a first preset doped semiconductor layer on a side of the first tunneling layer away from the substrate;

[0026] doping boron and gallium elements in the first preset doped semiconductor layer to form a first doped semiconductor layer, wherein a doping concentration of the boron element gradually decreases and a doping concentration of the gallium element gradually increases in a direction in which the first surface points to the second surface.

[0027] In some embodiments, the step of doping boron and gallium elements in the first preset doped semiconductor layer comprises:

[0028] doping boron elements in the first preset doped semiconductor layer by an ion implantation process with an ion implantation kinetic energy of 10 keV-30 keV;

[0029] doping gallium elements in the first preset doped semiconductor layer by an ion implantation process with an ion implantation kinetic energy of 30 keV-50 keV.

[0030] In some embodiments, the step of doping boron and gallium elements in the first preset doped semiconductor layer comprises:

[0031] simultaneously doping boron and gallium elements in the first preset doped semiconductor layer by a diffusion process of a boron source and a gallium source at a temperature of 800°C-950°C for a time of 30 min-60 min.

[0032] In some embodiments, after the step of doping boron and gallium elements in the first preset doped semiconductor layer, the method further comprises:

[0033] laser annealing, wherein the laser has a wavelength of 300 nm-1200 nm, an energy density of 1 J / cm²-3 J / cm², a scanning speed of 50 mm / s-200 mm / s, and an annealing atmosphere of nitrogen.

[0034] In some embodiments, after the step of laser annealing, the method further comprises:

[0035] hydrogen plasma passivation treatment, wherein a radio frequency power is 300 W-500 W, a time is 10 min-30 min, and a hydrogen flow rate is 50 seem-100 seem.

[0036] In a third aspect, the present application provides a laminated battery, comprising a top battery, a bonding layer and a bottom battery which are sequentially stacked, wherein the bottom battery is the solar cell according to any one of the above.

[0037] In a fourth aspect, the present application provides a photovoltaic module, comprising:

[0038] a battery string connected by a plurality of solar cells according to any one of the above, or connected by a plurality of solar cells manufactured by the manufacturing method according to any one of the above, or connected by the laminated battery according to the above;

[0039] a connecting component for electrically connecting two adjacent solar cells;

[0040] an encapsulation film for covering the surface of the battery string;

[0041] a cover plate for covering the surface of the encapsulation film away from the battery string.

[0042] In the embodiments of the present application, the first doped semiconductor layer is doped with boron elements and gallium elements, and in the direction (third direction) from the first surface to the second surface, the doping concentration of the boron elements gradually decreases, and the doping concentration of the gallium elements gradually increases. First, by introducing gallium elements to replace boron elements, the formation of B-O bond complexes in the substrate is reduced, thereby improving or solving the problem of light-induced degradation (LID). Second, through the gradient doping design, a high boron element concentration is maintained near the first tunneling layer to ensure low contact resistance, and the gallium element concentration is increased away from the first tunneling layer to suppress boron element diffusion, thereby optimizing the carrier transport performance. Third, in combination with the manufacturing method of the solar cell of the embodiments of the present application, the manufacturing process of the solar cell can be compatible with the existing production line, providing a mass-producible doping and passivation synergistic process, avoiding high equipment modification costs. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments or exemplary embodiments of the present application, the drawings needed in the description of the embodiments or exemplary embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0044] Figure 1 A schematic view of the cross-sectional structure of the first solar cell provided in some embodiments of the present application.

[0045] Figure 2 A schematic view of the cross-sectional structure of the first solar cell provided in some embodiments of the present application. Figure 1 A schematic view of the cross-sectional structure of the first solar cell provided in some embodiments of the present application.

[0046] Figure 3 A schematic diagram of a cross-sectional structure of a third solar cell provided for some embodiments of the present application.

[0047] Figure 4 A schematic diagram of a cross-sectional structure of a third solar cell provided for some embodiments of the present application.

[0048] Figure 5 A schematic diagram of a flow step of a manufacturing method of a solar cell provided for some embodiments of the present application.

[0049] Figure 6 Another schematic diagram of a flow step of a manufacturing method of a solar cell provided for some embodiments of the present application.

[0050] Figure 7 A schematic diagram of a comparison result of some embodiments of the present application and related art.

[0051] Figure 8 A schematic diagram of a structure of a photovoltaic module provided for some embodiments of the present application.

[0052] Reference signs: photovoltaic module 200; solar cell 100; substrate 11; first tunneling layer 21; first doped semiconductor layer 22; first surface 111; second surface 112; boron element a1; gallium element a2; first sub-surface part 211; second sub-surface part 212; first passivation layer 23; first electrode 24; emitter layer 12; second passivation layer 13; second electrode 14; second tunneling layer 31; second doped conductive layer 32; second passivation layer 33; second electrode 34;

[0053] First direction Y; second direction X; third direction Y1; first sub-surface 2101; second sub-surface 2102; textured structure R1; cell string 203; connecting part 204; encapsulation adhesive film 202; cover plate 201. DETAILED DESCRIPTION

[0054] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application can be practiced without some or all of these details under other conditions and / or methods. Therefore, the specific details disclosed below are not intended to limit the scope of the present application, but merely to illustrate a particular way of making and using it.

[0055] In the description of the present application, it should be understood that, if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, these terms indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply 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 a limitation on the present application.

[0056] In addition, if the terms "first", "second" appear, these terms are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, if the term "multiple" appears, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0057] In the present application, unless otherwise explicitly specified and limited, if the terms "mounting", "connecting", "connecting", "fixing" and the like appear, these terms should be broadly understood. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0058] In the present application, unless otherwise explicitly specified and limited, if the first feature is described as "on" or "under" the second feature, etc., it can mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" of the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" of the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0059] It should be noted that, if an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or there can be an intervening element. If an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be an intervening element. The terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar expressions used herein are used only for the purpose of illustration and do not indicate the only embodiment.

[0060] Referring to Figures 1 to 4 . Figure 1 A schematic diagram of a cross-sectional structure of a first solar cell provided for some embodiments of the present application. Figure 2 For Figure 1 A partial enlarged schematic diagram of the film layer on the second surface side. Figure 3 A schematic diagram of a cross-sectional structure of a second solar cell provided for some embodiments of the present application. Figure 4 A schematic diagram of a cross-sectional structure of a third solar cell provided for some embodiments of the present application.

[0061] It should be noted that, Figure 2 For Figure 1 , Figure 3 , Figure 4 A partial enlarged schematic diagram of the film layer on the second surface side.

[0062] In a first aspect, the present application provides a solar cell 100, which comprises a substrate 11, a first tunneling layer 21, and a first doped semiconductor layer 22. The substrate 11 has a first surface 111 and a second surface 112 arranged oppositely; the first tunneling layer 21 is located on one side of the second surface 112; the first doped semiconductor layer 22 is located on a side of the first tunneling layer 21 away from the substrate 11; wherein the first doped semiconductor layer 22 is doped with boron elements and gallium elements, and in a direction from the first surface 111 to the second surface 112, the doping concentration of the boron elements gradually decreases, and the doping concentration of the gallium elements gradually increases.

[0063] For example, the substrate 11 can have a doped element inside, which can be an N-type or P-type element. The N-type element can be a group V element such as phosphorus (P) element, bismuth (Bi) element, antimony (Sb) element, or arsenic (As) element. The P-type element can be a group III element such as boron (B) element, aluminum (Al) element, gallium (Ga) element, or indium (In) element. For example, when the substrate 11 is a P-type substrate, the internal doped element is a P-type element. For another example, when the substrate 11 is an N-type substrate, the internal doped element is an N-type element.

[0064] For example, the substrate 11 has a first surface 111 and a second surface 112 arranged oppositely. The first surface 111 and the second surface 112 are arranged oppositely along a thickness direction of the substrate 11. Both the first surface 111 and the second surface 112 can be used to receive incident light.

[0065] For example, in some embodiments, as shown in FIG. 1A, the first surface 111 of the substrate 11 (e.g., the first surface 111 is a front surface) is a main light-receiving surface, and the second surface 112 of the substrate 11 (e.g., the second surface 112 is a back surface) is a secondary light-receiving surface. Figure 1

[0066] For example, in some other embodiments, as shown in FIG. 1B, the second surface 112 of the substrate 11 (e.g., the second surface 112 is a front surface) is a main light-receiving surface, and the first surface 111 of the substrate 11 (e.g., the first surface 111 is a back surface) is a secondary light-receiving surface. Figure 3

[0067] It can be understood that the light-receiving surface and the back surface are relative. The light-receiving surface is specifically a surface on which the substrate 11 is mainly irradiated by sunlight in a solar cell or in a photovoltaic module. With the development of solar cell technology, the back surface will also receive energy from sunlight, mainly from reflected or scattered light in the surrounding environment.

[0068] For example, as shown in FIG. 2A, the first direction Y is a direction perpendicular to a plane on which the second surface 112 is located, and the first direction Y is also a thickness direction of the substrate 11. Figures 1 to 4

[0069] For example, as shown in FIG. 2B, the second direction X is a direction parallel to a plane on which the second surface 112 is located, and the second direction X is also perpendicular to the thickness of the substrate 11. Figures 1 to 4

[0070] For example, as shown in FIG. 3A, a direction in which the first surface 111 points to the second surface 112 is a third direction Y1, and the third direction Y1 is parallel to the first direction Y. Figures 1 to 4

[0071] For example, as shown in FIG. 4A, the first doped semiconductor layer 22 is doped with boron elements a1 and gallium elements a2. In a direction in which the first surface 111 points to the second surface 112 (the third direction Y1), the doping concentration of the boron elements a1 gradually decreases, and the doping concentration of the gallium elements a2 gradually increases. Figure 2 Figure 2

[0072] Figure 2 ​​​​​​​​As shown, the first doped semiconductor layer 22 has a first sub-surface portion 211 close to the first surface 111 / second surface 112, and a second sub-surface portion 212 away from the first surface 111 / second surface 112. The doping concentration of the boron element a1 in the first sub-surface portion 211 is greater than that of the second sub-surface portion 212. The doping concentration of the gallium element a2 in the first sub-surface portion 211 is less than that of the second sub-surface portion 212.

[0073] For example, in the related art, the first doped semiconductor layer 22 is only doped with boron element, and in the third direction Y1, the doping concentration of the boron element is uniform, however, after various process steps, B-O complex is easily formed in the substrate 11, thereby causing the problem of light-induced degradation (LID); and boron element diffusion is easily formed away from the substrate 11, thereby reducing the carrier transport performance.

[0074] In the embodiment of the present application, the first doped semiconductor layer 22 is doped with boron element and gallium element, and in the direction (third direction Y1) in which the first surface 111 points to the second surface 112, the doping concentration of the boron element gradually decreases, and the doping concentration of the gallium element gradually increases. First, by introducing the gallium element to replace the boron element, the formation of B-O bond complex in the substrate 11 is reduced, thereby improving or solving the problem of light-induced degradation (LID). Second, through the gradient doping design, high boron element concentration is maintained near the first tunneling layer 21 to ensure low contact resistance, and the gallium element concentration is increased away from the first tunneling layer 21 to inhibit boron element diffusion, thereby the carrier transport performance can be optimized. Third, in combination with the manufacturing method of the solar cell of the present application, the manufacturing process of the solar cell 100 can be compatible with the existing production line, providing a mass-producible doping and passivation synergistic process, avoiding high equipment modification cost.

[0075] In some embodiments, as shown in Figure 1 and Figure 2 As shown, the first doped semiconductor layer 22 has a first sub-surface portion 211 close to the first surface 111, and a second sub-surface portion 212 away from the first surface 111; in the first sub-surface portion 211, the doping concentration of the boron element is greater than that of the gallium element; in the second sub-surface portion 212, the doping concentration of the boron element is greater than that of the gallium element.

[0076] For example, as shown in Figure 2As shown, the first doped semiconductor layer 22 has a first sub-surface portion 211 close to the first surface 111, and a second sub-surface portion 212 away from the first surface 111. The first sub-surface portion 211 is a first end portion of the first doped semiconductor layer 22 close to the first surface 111 in the first direction Y. The second sub-surface portion 212 is a second end portion of the first doped semiconductor layer 22 away from the first surface 111 in the first direction Y. The first doped semiconductor layer 22 includes a first sub-surface 2101 close to the first surface 111, and a second sub-surface 2102 away from the first surface 111. For example, the first doped semiconductor layer 22 extends from the first sub-surface 2101 to the first sub-surface portion 211 by any value in a range of 20 nm to 30 nm. For example, the first doped semiconductor layer 22 extends from the second sub-surface 2102 to the second sub-surface portion 212 by any value in a range of 20 nm to 30 nm.

[0077] For example, as shown in FIG. 2A, the first doped semiconductor layer 22 includes a first sub-surface 2101 close to the first surface 111, and a second sub-surface 2102 away from the first surface 111. Figure 2 As shown, in the first sub-surface portion 211, the doping concentration of the boron element is greater than the doping concentration of the gallium element; in the second sub-surface portion 212, the doping concentration of the boron element is greater than the doping concentration of the gallium element, so that the main doping effect of the boron element is maintained.

[0078] For example, as shown in FIG. 2A, the first doped semiconductor layer 22 includes a first sub-surface 2101 close to the first surface 111, and a second sub-surface 2102 away from the first surface 111. Figures 1 to 4 For example, in the first doped semiconductor layer 22, the doping concentration of the boron element is 1 x 1018cm-3 to 5 x 1018cm-3, and the doping concentration of the gallium element is 1 x 1018cm-3 to 5 x 1018cm-3. 20 cm -3 -5 x 1018cm-3. 19 cm -3 .

[0079] For example, in the first doped semiconductor layer 22, the doping concentration of the boron element is 1 x 1018cm-3 to 5 x 1018cm-3, and the doping concentration of the gallium element is 1 x 1018cm-3 to 5 x 1018cm-3. 20 cm -3 -5 x 1018cm-3. 19 cm -3 , the doping concentration of the boron element can be 5 x 1018cm-3, 5.5 x 1018cm-3, 6 x 1018cm-3, 6.5 x 1018cm-3, 7 x 1018cm-3, 7.5 x 1018cm-3, 8 x 1018cm-3, 8.5 x 1018cm-3, 9 x 1018cm-3, 9.5 x 1018cm-3, or 1 x 1019cm-3. 19 cm -3 , the doping concentration of the boron element can be 5 x 1018cm-3, 5.5 x 1018cm-3, 6 x 1018cm-3, 6.5 x 1018cm-3, 7 x 1018cm-3, 7.5 x 1018cm-3, 8 x 1018cm-3, 8.5 x 1018cm-3, 9 x 1018cm-3, 9.5 x 1018cm-3, or 1 x 1019cm-3. 19 cm -3 , the doping concentration of the boron element can be 5 x 1018cm-3, 5.5 x 1018cm-3, 6 x 1018cm-3, 6.5 x 1018cm-3, 7 x 1018cm-3, 7.5 x 1018cm-3, 8 x 1018cm-3, 8.5 x 1018cm-3, 9 x 1018cm-3, 9.5 x 1018cm-3, or 1 x 1019cm-3. 19 cm -3 , the doping concentration of the boron element can be 5 x 1018cm-3, 5.5 x 1018cm-3, 6 x 1018cm-3, 6.5 x 1018cm-3, 7 x 1018cm-3, 7.5 x 1018cm-3, 8 x 1018cm-3, 8.5 x 1018cm-3, 9 x 1018cm-3, 9.5 x 1018cm-3, or 1 x 1019cm-3. 19 cm -3 , the doping concentration of the boron element can be 5 x 1018cm-3, 5.5 x 1018cm-3, 6 x 1018cm-3, 6.5 x 1018cm-3, 7 x 1018cm-3, 7.5 x 1018cm-3, 8 x 1018cm-3, 8.5 x 1018cm-3, 9 x 1018cm-3, 9.5 x 1018cm-3, or 1 x 1019cm-3. 19 cm -3 , the doping concentration of the boron element can be 5 x 1018cm-3, 5.5 x 1018cm-3, 6 x 1018cm-3, 6.5 x 1018cm-3, 7 x 1018cm-3, 7.5 x 1018cm-3, 8 x 1018cm-3, 8.5 x 1018cm-3, 9 x 1018cm-3, 9.5 x 1018cm-3, or 1 x 1019cm-3. 19 cm -3 , the doping concentration of the boron element can be 5 x 1018cm-3, 5.5 x 1018cm-3, 6 x 1018cm-3, 6.5 x 1018cm-3, 7 x 1018cm-3, 7.5 x 1018cm-3, 8 x 1018cm-3, 8.5 x 1018cm-3, 9 x 1018cm-3, 9.5 x 1018cm-3, or 1 x 1019cm-3. 19 cm -3 , the doping concentration of the boron element can be 5 x 1018cm-3, 5.5 x 1018cm-3, 6 x 1018cm-3, 6.5 x 1018cm-3, 7 x 1018cm-3, 7.5 x 1018cm-3, 8 x 1018cm-3, 8.5 x 1018cm-3, 9 x 1018cm-3, 9.5 x 1018cm-3, or 1 x 1019cm-3. 19 cm -3 , the doping concentration of the boron element can be 5 x 1018cm-3, 5.5 x 1018cm-3, 6 x 1018cm-3, 6.5 x 1018cm-3, 7 x 1018cm-3, 7.5 x 1018cm-3, 8 x 1018cm-3, 8.5 x 1018cm-3, 9 x 1018cm-3, 9.5 x 1018cm-3, or 1 x 1019cm-3. 19 cm -39.5×10 19 cm -3 1×10 20 cm -3 Any value in the range.

[0080] In some implementations, such as Figures 1 to 4 As shown, in the first doped semiconductor layer 22, the gallium doping concentration is 1×10⁻⁶. 18 cm -3 -1×10 19 cm -3 .

[0081] For example, in the first doped semiconductor layer 22, the gallium doping concentration can be 1 × 10⁻⁶. 18 cm -3 2×10 18 cm -3 3×10 18 cm -3 4×10 18 cm -3 5×10 18 cm -3 6×10 18 cm -3 7×10 18 cm -3 8×10 18 cm -3 9×10 18 cm -3 1×10 19 cm -3 Any value in the range.

[0082] For example, such as Figures 1 to 4 As shown, in the first doped semiconductor layer 22, the boron doping concentration is 1×10⁻⁶. 20 cm -3 -5×10 19 cm -3 The gallium doping concentration is 1×10⁻⁶. 18 cm -3 -1×10 19 cm -3 .

[0083] For example, such as Figures 1 to 4 As shown, in the first aspect, the boron doping concentration in the first sub-surface portion 211 is 1×10⁻⁶. 20 cm -3 Or, in the vicinity of this value, the gallium doping concentration is 1×10⁻⁶. 18 cm -3At or around this value, the boron doping concentration is high (compared to the boron doping of the second sub-surface 212), while the gallium doping concentration is low (compared to the gallium doping of the second sub-surface 212). The boron and gallium elements work synergistically. The higher concentration of boron doping ensures good electrical connection performance with the first electrode 24, guaranteeing low resistance conduction. The lower concentration of gallium doping suppresses the formation of BO pairs. This concentration of gallium is sufficient to compete with boron at the atomic scale, preferentially combining with interstitial oxygen in the substrate or occupying key positions, thereby fundamentally preventing the formation of BO pairs, the culprit of light-induced degradation (LID). Furthermore, excessively high boron concentrations can exceed the solid solubility of boron in the substrate 11, leading to defects such as boron clusters, which can become recombination centers and potentially damage the ultrathin tunneling oxide layer. Low gallium doping concentrations can avoid interfering with tunneling, while excessively high gallium doping concentrations may introduce too many defects and Coulomb scattering, interfering with the hole tunneling process and increasing resistance. Setting boron and gallium doping in the first sub-surface portion 211 within the aforementioned range or values ​​can improve or avoid these problems.

[0084] For example, such as Figures 1 to 4 As shown, in the second aspect, the boron doping concentration in the second sub-surface portion 212 is 5 × 10⁻⁶. 19 cm -3 Or, in the vicinity of this value, the gallium doping concentration is 1×10⁻⁶. 19 cm -3 At or near this value, the boron doping concentration is low (compared to the boron doping of the first sub-surface 211), while the gallium doping concentration is high (compared to the gallium doping of the first sub-surface 211). Boron and gallium work synergistically; the higher gallium concentration suppresses boron diffusion, and the higher gallium concentration further "fixes" and "stabilizes" boron atoms, forming an effective diffusion barrier layer. This prevents unfavorable diffusion of boron in any direction during long-term operation or high-temperature processes, significantly reducing boron diffusion into the bulk region of the substrate 11 during subsequent high-temperature processes. This avoids the formation of a dead layer due to boron diffusion and prevents a reduction in the minority carrier lifetime of the substrate 11's bulk region. Furthermore, this boron concentration is sufficient to ensure good lateral conductivity of the first doped semiconductor layer 22, ensuring uniform current collection. This gallium concentration is close to the solid solubility limit of gallium in the substrate 11, maximizing its "barrier" effect without generating harmful gallium clusters. This improves the thermal stability and long-term reliability of the doped structure, ensuring the durability of battery performance.

[0085] Therefore, by performing gradient co-doping of boron and gallium in the first doped semiconductor layer 22 on the third-direction Y1, the following synergistic effect is generated: using boron to achieve excellent electrical performance (conduction and field passivation), and using gallium to build a strong defense system (anti-attenuation and stable structure), the first doped semiconductor layer 22 is no longer a simple conductive layer in the traditional sense, but a "smart" composite functional layer that integrates efficient carrier transport, top-level surface passivation and intrinsic anti-attenuation functions.

[0086] In some implementations, such as Figures 1 to 4 As shown, in the first sub-surface portion 211, the boron doping concentration is 0.7 × 10⁻⁶. 20 cm -3 -1.5×10 20 cm -3 ; and / or, in the first sub-surface portion 211, the gallium doping concentration is 0.5 × 10⁻⁶. 18 cm -3 -3×10 18 cm -3 After considering process variations, the boron doping concentration in the first sub-surface portion 211 is 1×10⁻⁶. 20 cm -3 Or, near this value, the gallium doping concentration is 1×10⁻⁶. 18 cm -3 Alternatively, based on values ​​near this range, the doping concentrations of boron and gallium can be set within this range.

[0087] For example, in the first sub-surface portion 211, the boron doping concentration can be 0.7 × 10⁻⁶. 20 cm -3 0.8×10 20 cm -3 0.9×10 20 cm -3 1×10 20 cm -3 1.1×10 20 cm -3 1.2×10 20 cm -3 1.3×10 20 cm -3 1.4×10 20 cm -3 1.5×10 20 cm -3 Any value in the range.

[0088] For example, in the first sub-surface portion 211, the gallium doping concentration can be 0.5 × 10⁻⁶. 18 cm-3 0.8×10 18 cm -3 1×10 18 cm -3 1.2×10 18 cm -3 1.5×10 18 cm -3 1.8×10 18 cm -3 2×10 18 cm -3 2.3×10 18 cm -3 2.5×10 18 cm -3 2.8×10 18 cm -3 3×10 18 cm -3 Any value in the range.

[0089] In some implementations, such as Figures 1 to 4 As shown, in the second sub-surface portion 212, the boron doping concentration is 3 × 10⁻⁶. 19 cm -3 -8×10 19 cm -3 ; and / or, in the second sub-surface portion 212, the gallium doping concentration is 0.7 × 10⁻⁶. 19 cm -3 -2×10 19 cm -3 After considering process fluctuations, the boron doping concentration in the first sub-surface portion 211 is 5 × 10⁻⁶. 19 cm -3 Or, near this value, the gallium doping concentration is 1×10⁻⁶. 19 cm -3 Alternatively, based on values ​​near this range, the doping concentrations of boron and gallium can be set within this range.

[0090] For example, in the second sub-surface portion 212, the boron doping concentration can be 3 × 10⁻⁶. 19 cm -3 3.5×10 19 cm -3 4×10 19 cm -3 4.5×10 19 cm -3 5×10 19 cm -3 5.5×10 19 cm -3 6×10 19cm -3 , 6.5 x 10 19 cm -3 , 7 x 10 19 cm -3 , 7.5 x 10 19 cm -3 , 8 x 10 19 cm -3 , or any value within the range.

[0091] For example, in the second sub-surface portion 212, the doping concentration of the gallium element can be any value within the range of 0.7 x 10 19 cm -3 , 0.9 x 10 19 cm -3 , 1 x 10 19 cm -3 , 1.2 x 10 19 cm -3 , 1.5 x 10 19 cm -3 , 1.8 x 10 19 cm -3 , 2 x 10 19 cm -3 , or any value within the range.

[0092] For example, by gradiently co-doping boron and gallium in the first doped semiconductor layer 22 in the third direction Y1, the following synergistic effects can be achieved when the boron and gallium are strictly co-doped within the above-mentioned concentration ranges: the boron is used to achieve excellent electrical performance (turn-on and field passivation), and the gallium is used to build a strong defense system (anti-fading and structure stabilization), so that the first doped semiconductor layer 22 is no longer a simple conductive layer in the traditional sense, but a “smart” composite functional layer that integrates efficient carrier transport, top surface passivation, and intrinsic anti-fading functions. More specifically, including: 1) excellent anti-light-induced degradation performance: the LID degradation rate is reduced from >1% for traditional B-doped to <0.5%, or even lower; a sufficient number of gallium atoms (>5 x 10 17 cm -3 ) interact with oxygen first, fundamentally inhibiting the formation of B-O pairs. 2) High open-circuit voltage and excellent passivation effect, improving Voc: on the one hand, the introduction of gallium and hydrogen passivation (described in subsequent examples) synergistically reduces interface recombination; on the other hand, the upper limit of the surface gallium concentration (<2 x 10 19 cm -3 ) prevents the formation of gallium clusters and avoids new bulk recombination centers; at the same time, the gradient distribution of boron reduces its diffusion to the bulk of the substrate, protecting the minority carrier lifetime. 3) Low series resistance and high fill factor: high boron concentration at the interface (>7 x 10 19 cm-3 This ensures excellent ohmic contact; moderate gallium concentration (interface <3×10⁻⁶) 18 cm -3 4) Excellent process window and stability: The concentration range is set to take into account actual process fluctuations and is not a fragile "singularity"; the low diffusion coefficient and "barrier layer" effect of gallium ensure that the doping distribution remains stable during high-temperature processes and long-term operation; hydrogen passivation (described in subsequent examples) can effectively stabilize the doped structure and repair minor damage introduced during the process.

[0093] In some implementations, such as Figures 1 to 4 As shown, the material of the first tunneling layer 21 includes silicon oxide, and the material of the first doped semiconductor layer 22 includes polycrystalline silicon; and / or, the thickness of the first tunneling layer 21 is 1nm-2nm, and the thickness of the first doped semiconductor layer 22 is 50nm-150nm.

[0094] For example, the thickness of the first tunneling layer 21 is 1nm-2nm, and the thickness of the first tunneling layer 21 can be any value among 1nm, 1.1nm, 1.2nm, 1.3nm, 1.4nm, 1.5nm, 1.6nm, 1.7nm, 1.8nm, 1.9nm, and 2nm.

[0095] For example, the thickness of the first doped semiconductor layer 22 is 50nm-150nm, and the thickness of the first doped semiconductor layer 22 can be any value among 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, and 150nm.

[0096] In some implementations, such as Figure 1 As shown, the first doped semiconductor layer 22 is also doped with hydrogen, and the hydrogen doping concentration is 1×10⁻⁶. 19 cm -3 -1×10 20 cm -3 .

[0097] For example, the first doped semiconductor layer 22 can be subjected to a hydrogen passivation process to further reduce the interface state density and decrease carrier recombination losses. The hydrogen doping concentration can be 1 × 10⁻⁶. 19 cm -3 2×10 19 cm -3 3×10 19 cm -3 4×10 19 cm -3 5×10 19 cm-3 6 x 10 19 cm -3 7 x 10 19 cm -3 8 x 10 19 cm -3 9 x 10 19 cm -3 1 x 10 20 cm -3 Any of the numerical values.

[0098] It should be noted that, as shown in Figure 3 and Figure 1 , the solar cell 100 can also include a first passivation layer 23 located on the side of the first doped semiconductor layer 22 away from the substrate 11, and a first electrode 24 located on the side of the first passivation layer 23 away from the substrate 11, the first electrode 24 being electrically connected to the first doped semiconductor layer 22. The material of the first passivation layer 23 can include at least one of silicon oxide, silicon nitride, and silicon oxynitride.

[0099] It should be noted that, as shown in Figure 3 and Figure 1 , the solar cell 100 of the present application is exemplified by taking a tunnel oxide passivated contact (TOPCon) cell as an example, and the first tunnel layer 21 and the first doped semiconductor layer 22 can also be applied to other types of solar cells, for example, can be applied to a BC cell.

[0100] It should be noted that, as shown in Figure 3 and Figure 1 , the solar cell 100 further includes an emitter layer 12, a second passivation layer 13, and a second electrode 14, the emitter layer 12 being located on the side of the first surface 111, the second passivation layer 13 being located on the side of the emitter layer 12 away from the substrate 11, and the second electrode 14 being located on the side of the second passivation layer 13 away from the substrate 11, the second electrode 14 being electrically connected to the emitter layer 12.

[0101] It should be noted that, in some embodiments, as shown in Figure 3 , in a TOPCon cell, the first surface 111 of the substrate 11 is a front surface, and the first surface 111 can further have a plurality of textured structures R1, which can be a pyramid structure or an inverted pyramid structure, without being limited thereto. Figure 4 , in some embodiments, as shown in , in a TOPCon cell, the second surface 112 of the substrate 11 is a front surface, and the second surface 112 can further have a plurality of textured structures R1, which can be a pyramid structure or an inverted pyramid structure, without being limited thereto.

[0102] It should be noted that, as shown in Figure 4 The solar cell 100 also includes a second tunneling layer 31, a second doped conductive layer 32, a second passivation layer 33, and a second electrode 34. The second tunneling layer 31 is located on one side of the first surface 111. The second doped conductive layer 32 is located on the side of the second tunneling layer 31 away from the substrate 11. The second passivation layer 33 is located on the side of the second doped conductive layer 32 away from the substrate 11. The second electrode 34 is located on the side of the second passivation layer 33 away from the substrate 11. The second electrode 34 is electrically connected to the second doped conductive layer 32. That is Figure 4 The double-sided oxide passivation contact cell (double-sided TOPCon) is illustrated.

[0103] It should be noted that, in the Figure 5 The double-sided oxide passivation contact cell (double-sided TOPCon) is illustrated. The second doped conductive layer 32 can include polysilicon, and the second doped conductive layer 32 can be doped with phosphorus elements, but is not limited thereto.

[0104] Please refer to Figure 6 and Figure 5 , Figure 6 A flow step schematic diagram of a manufacturing method of a solar cell provided by an embodiment of the present application is shown. Figure 5 Another flow step schematic diagram of a manufacturing method of a solar cell provided by an embodiment of the present application is shown.

[0105] In a second aspect, based on the same application concept, as shown in Figure 6 and Figure 5 The present application also provides a manufacturing method of a solar cell. The solar cell 100 of any one of the above embodiments can be manufactured by using the manufacturing method of the solar cell. As shown in Figure 6 The manufacturing method of the solar cell includes steps S100, S200, S300, and S400.

[0106] In step S100, a substrate is provided. The substrate has a first surface and a second surface arranged opposite to each other.

[0107] For example, a substrate 11 is provided. The substrate 11 has a first surface 111 and a second surface 112 arranged opposite to each other.

[0108] In step S200, a first tunneling layer is formed on the second surface.

[0109] For example, a first tunneling layer 21 is formed on the second surface 112.

[0110] In step S300, a first pre-doped semiconductor layer is formed on the side of the first tunneling layer away from the substrate.

[0111] For example, the first preset doped semiconductor layer is formed on the side of the first tunneling layer 21 away from the substrate 11.

[0112] For example, the first preset doped semiconductor layer is a film layer of the first doped semiconductor layer 22 before being doped with boron elements and gallium elements, and can be a polysilicon film layer.

[0113] In step S400, the first doped semiconductor layer is formed by doping the first preset doped semiconductor layer with boron elements and gallium elements. In the direction in which the first surface points to the second surface, the doping concentration of the boron elements gradually decreases, and the doping concentration of the gallium elements gradually increases.

[0114] For example, the first doped semiconductor layer 22 is formed by doping the first preset doped semiconductor layer with boron elements and gallium elements. In the direction in which the first surface 111 points to the second surface 112, the doping concentration of the boron elements gradually decreases, and the doping concentration of the gallium elements gradually increases.

[0115] For example, the first doped semiconductor layer 22 is formed by doping the first preset doped semiconductor layer with boron elements and gallium elements in step S400. In the third direction Y1, the doping concentration of the boron elements gradually decreases, and the doping concentration of the gallium elements gradually increases.

[0116] It should be noted that in the method for manufacturing a solar cell, any one of the above-mentioned solar cells 100 can be manufactured, and has the beneficial effects described above.

[0117] In some embodiments, the step of doping the first preset doped semiconductor layer with boron elements and gallium elements (step S400) includes: doping the first preset doped semiconductor layer with boron elements by an ion implantation process, and the ion implantation kinetic energy is 10 keV-30 keV; and doping the first preset doped semiconductor layer with gallium elements by an ion implantation process, and the ion implantation kinetic energy is 30 keV-50 keV.

[0118] For example, the ion implantation kinetic energy for doping the first preset doped semiconductor layer with boron elements by an ion implantation process can be any one of 10 keV, 12 keV, 15 keV, 18 keV, 20 keV, 22 keV, 25 keV, 28 keV, and 30 keV.

[0119] For example, the ion implantation kinetic energy for doping the first preset doped semiconductor layer with gallium elements by an ion implantation process can be any one of 30 keV, 35 keV, 40 keV, 45 keV, and 50 keV.

[0120] For example, there is an atomic mass difference between gallium and boron elements. Under the same implantation energy, heavy gallium ions are implanted much more shallowly than light boron ions. When doping into the first preset doped semiconductor layer, it is desirable that boron and gallium are distributed in approximately the same depth range to exert a synergistic effect. Therefore, the two different / suitable ion implantation kinetic energies for boron and gallium are set to enable the heavy gallium ions to reach a similar / same depth as the light boron ions.

[0121] For example, in the ion implantation process, gradient distribution can be achieved by using oblique implantation.

[0122] In some embodiments, the step of doping boron elements and gallium elements in the first preset doped semiconductor layer (step S400) includes simultaneously doping boron elements and gallium elements in the first preset doped semiconductor layer by a diffusion process of a boron source and a gallium source, at a temperature of 800-950°C for 30-60 minutes.

[0123] For example, a mixed solid-state source of boron nitride (BN) and potassium oxide (Ga2O3) can be used to diffuse at 800-950°C for 30-60 minutes to achieve a doping gradient by controlling the temperature gradient.

[0124] In some embodiments, as shown in Figure 6 After the step of doping boron elements and gallium elements in the first preset doped semiconductor layer (step S400), the method further includes a step S500 of laser annealing, with a wavelength of 300-1200 nm, an energy density of 1-3 J / cm2, a scanning speed of 50-200 mm / s, and an annealing atmosphere of nitrogen.

[0125] For example, the above laser annealing process can activate the doping atoms. The low-temperature activation process selectively activates the dopants by laser annealing, avoids Ga aggregation caused by high-temperature processes, reduces the thermal budget, and improves production efficiency.

[0126] In some embodiments, as shown in Figure 7 After the step of laser annealing (step S500), the method further includes a step S600 of hydrogen plasma passivation treatment, with a radio frequency power of 300-500 W, a time of 10-30 minutes, and a hydrogen flow rate of 50-100 sccm.

[0127] For example, the hydrogen plasma passivation treatment is performed at a temperature of 350 o C-450 oC, the radio frequency power is 300W-500W, the time is 10min-30min, and the hydrogen flow is 50sccm-100sccm. The temperature / radio frequency power is appropriate, on the one hand, the diffusion capacity of hydrogen atoms in the silicon and polycrystalline silicon network is insufficient, which cannot effectively migrate to the interface to passivate defects (such as dangling bonds), resulting in poor passivation effect; on the other hand, the hydrogen diffusion is too fast, which can avoid the hydrogen escape (avoiding that the Si-H bond and Ga-H bond which have passivated defects can be broken due to thermal vibration, and the hydrogen atoms escape from the structure), and avoid causing the "depassivation" effect; in addition, it can avoid causing the dopant redistribution, and for the fine gradient doping structure formed by laser annealing, high temperature and the like can cause unnecessary redistribution of boron (B) and gallium (Ga) atoms, which can destroy the designed gradient distribution.

[0128] Please refer to Figure 7 , Figure 7 is a schematic diagram of the comparison results of the embodiments of the present application and related art. The solar cell 100 is obtained by using the manufacturing method of the solar cell described above in Embodiment 1 and Embodiment 2. In Embodiment 1, the ion implantation process is used to dope boron elements and gallium elements in step S400, and in Embodiment 2, the diffusion process is used to dope boron elements and gallium elements in step S400. The comparative example is a solar cell in which only boron elements are doped in the first doped semiconductor layer 22 in the related art. From Figure 8 it can be seen that, compared with the comparative example, the light-induced degradation (LID) in Embodiment 1 and Embodiment 2 is greatly improved, and the conversion efficiency is improved, which indicates that the solar cell 100 of any one of the above or the manufacturing method of the solar cell of any one of the above can well improve the light-induced degradation (LID), can improve the conversion efficiency of the solar cell, and can improve the performance of the solar cell.

[0129] In a third aspect, based on the same application concept, the present application further provides a stacked cell, which comprises a top cell, a bonding layer and a bottom cell arranged in sequence. The bottom cell is the solar cell 100 of any one of the above.

[0130] For example, in some embodiments, the top cell can be a perovskite solar cell, which comprises a laminated first transport layer, a perovskite substrate, a second transport layer, a transparent conductive layer and an anti-reflection layer. The first transport layer is opposite to the bottom cell. The first transport layer can be one of an electron transport layer or a hole transport layer, and the second transport layer can be the other one of the electron transport layer or the hole transport layer.

[0131] It should be noted that the stacked cell of the present application and the solar cell 100 of any one of the above are based on the same application concept, and the stacked cell and the solar cell 100 of any one of the above have the same or similar effects, which will not be described here.

[0132] Please refer to Figure 8 , ​ A structural schematic diagram of a photovoltaic module is provided for the embodiments of the present application.

[0133] In a fourth aspect, based on the same application concept, the present application further provides a photovoltaic module 200, which comprises: a cell string 203 connected by a plurality of solar cells 100 according to any one of the above embodiments, or connected by a plurality of solar cells 100 manufactured by the manufacturing method according to any one of the above embodiments, or connected by a laminated cell according to any one of the above embodiments; a connecting component 204 for electrically connecting two adjacent solar cells 100; an encapsulation adhesive film 202 for covering the surface of the cell string 203; and a cover plate 201 for covering the surface of the encapsulation adhesive film 202 away from the cell string 203.

[0134] For example, in some embodiments, the connecting component 204 can comprise a conductive strip, and a plurality of cell strings 203 can be electrically connected by the conductive strip. The encapsulation adhesive film 202 covers the front surface and the back surface of the solar cell or the laminated solar cell.

[0135] For example, in some embodiments, the encapsulation adhesive film 202 can be an ethylene-vinyl acetate copolymer (EVA) adhesive film, a polyethylene octene copolymer elastomer (POE) adhesive film, or a polyethylene terephthalate (PET) adhesive film, or the like organic encapsulation adhesive film.

[0136] For example, in some embodiments, the cover plate 201 can be a glass cover plate, a plastic cover plate, or the like cover plate having a light transmission function.

[0137] For example, in some embodiments, the surface of the cover plate 201 facing the encapsulation layer can be a concave-convex surface, thereby increasing the utilization rate of incident light.

[0138] It should be noted that the photovoltaic module 200 of the present application and the solar cell 100 according to any one of the above embodiments are based on the same application concept, and the photovoltaic module 200 and the solar cell 100 according to any one of the above embodiments have the same or similar effects, which will not be described here.

[0139] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0140] The above embodiments only express several implementation ways of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation to the patent scope of the application. It should be pointed out that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A solar cell, characterized in that, include: The substrate has a first surface and a second surface disposed opposite to each other; The first tunneling layer is located on one side of the second surface; The first doped semiconductor layer is located on the side of the first tunneling layer away from the substrate; In this process, the first doped semiconductor layer is doped with boron and gallium. In the direction from the first surface to the second surface, the doping concentration of boron gradually decreases and the doping concentration of gallium gradually increases.

2. The solar cell according to claim 1, characterized in that, The first doped semiconductor layer has a first sub-surface portion close to the first surface and a second sub-surface portion away from the first surface; In the first sub-surface portion, the doping concentration of boron is greater than the doping concentration of gallium. In the second sub-surface portion, the doping concentration of boron is greater than that of gallium.

3. The solar cell according to claim 1, characterized in that, In the first doped semiconductor layer, the boron doping concentration is 1 × 10⁻⁶. 20 cm -3 -5×10 19 cm -3 .

4. The solar cell according to claim 1, characterized in that, In the first doped semiconductor layer, the gallium doping concentration is 1×10⁻⁶. 18 cm -3 -1×10 19 cm -3 .

5. The solar cell according to claim 2, characterized in that, In the first sub-surface portion, the boron doping concentration is 0.7 × 10⁻⁶. 20 cm -3 -1.5×10 20 cm -3 ; and / or, In the first sub-surface portion, the gallium doping concentration is 0.5 × 10⁻⁶. 18 cm -3 -3×10 18 cm -3 .

6. The solar cell according to claim 2, characterized in that, In the second sub-surface portion, the boron doping concentration is 3 × 10⁻⁶. 19 cm -3 -8×10 19 cm -3 ; and / or, In the second sub-surface portion, the gallium doping concentration is 0.7 × 10⁻⁶. 19 cm -3 -2×10 19 cm -3 .

7. The solar cell according to claim 1, characterized in that, The material of the first tunneling layer includes silicon oxide, and the material of the first doped semiconductor layer includes polycrystalline silicon; and / or, The thickness of the first tunneling layer is 1nm-2nm, and the thickness of the first doped semiconductor layer is 50nm-150nm.

8. The solar cell according to claim 1, characterized in that, The first doped semiconductor layer is also doped with hydrogen, and the hydrogen doping concentration is 1×10⁻⁶. 19 cm -3 -1×10 20 cm -3 .

9. A method for manufacturing a solar cell, characterized in that, include: A substrate is provided, the substrate having a first surface and a second surface disposed opposite to each other; A first tunneling layer is formed on the second surface; A first pre-defined doped semiconductor layer is formed on the side of the first tunneling layer away from the substrate; Boron and gallium are doped in the first preset doped semiconductor layer to form a first doped semiconductor layer; in the direction from the first surface to the second surface, the doping concentration of boron gradually decreases and the doping concentration of gallium gradually increases.

10. The method for manufacturing a solar cell according to claim 9, characterized in that, The step of doping boron and gallium elements in the first preset doped semiconductor layer includes: Boron is doped into the first preset doped semiconductor layer by ion implantation, with an ion implantation kinetic energy of 10keV-30keV. Gallium is doped into the first preset doped semiconductor layer by ion implantation, with an ion implantation kinetic energy of 30keV-50keV.

11. The method for manufacturing a solar cell according to claim 9, characterized in that, The step of doping boron and gallium elements in the first preset doped semiconductor layer includes: In the first preset doped semiconductor layer, boron and gallium elements are simultaneously doped using diffusion processes with boron and gallium sources at a temperature of 800℃-950℃ for a time of 30min-60min.

12. The method for manufacturing a solar cell according to claim 9, characterized in that, After the step of doping boron and gallium elements in the first preset doped semiconductor layer, the method further includes: Laser annealing, wherein the wavelength of the laser is 300nm-1200nm, the energy density is 1J / cm²-3J / cm², the scanning speed is 50mm / s-200mm / s, and the annealing atmosphere is nitrogen.

13. The method for manufacturing a solar cell according to claim 12, characterized in that, Following the laser annealing step, the method further includes: Hydrogen plasma passivation treatment, with a radio frequency power of 300W-500W, a time of 10min-30min, and a hydrogen flow rate of 50sccm-100sccm.

14. A stacked battery, characterized in that, It includes a top cell, an adhesive layer, and a bottom cell stacked in sequence, wherein the bottom cell is a solar cell as described in any one of claims 1 to 8.

15. A photovoltaic module, characterized in that, include: A battery string, consisting of multiple solar cells connected as described in any one of claims 1 to 8, or multiple solar cells manufactured by the method of manufacturing solar cells as described in any one of claims 9 to 13, or multiple tandem solar cells as described in claim 14; a connecting member for electrically connecting two adjacent solar cells; An encapsulating film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulating film that faces away from the battery string.

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