Solar cells and photovoltaic modules

Abstract

The application relates to the technical field of photovoltaic solar cells, and discloses a solar cell and a photovoltaic module. The solar cell comprises a silicon substrate, the silicon substrate has a first surface and a second surface arranged oppositely, a medium layer arranged on the second surface, and a doped layer arranged on the surface of the medium layer away from the silicon substrate, wherein the surface of the doped layer away from the medium layer has a plurality of submicron particles. In the application, the roughness of the doped layer can be effectively increased through the plurality of submicron particles on the surface of the doped layer away from the medium layer, the back surface reflection of the cell sheet can be reduced through the submicron particles, the light absorption capacity of the film layer can be improved, and the contact area with metal can be increased, so that the doped layer has better metal contact performance.

Description

Technical Field

[0001] This application relates to the field of photovoltaic solar cell technology, and more particularly to a solar cell and a photovoltaic module. Background Technology

[0002] Crystalline silicon solar cells, through the photovoltaic effect, directly convert solar energy into electrical energy, effectively utilizing solar energy. Their fabrication process employs deposition techniques to prepare films using amorphous silicon, microcrystalline silicon, or polycrystalline silicon. These techniques primarily include low-pressure chemical vapor deposition (LPCVD) and plasma-enhanced chemical vapor deposition (PECVD). Both deposition techniques use silane as the reactive gas; the silane decomposes at high temperatures or under the assistance of an alternating electric field to form the film.

[0003] However, the film layer formed by the above technology has a smooth surface, which makes it impossible to form good contact with the metal, which is not conducive to the light absorption of the solar cell. Utility Model Content

[0004] This application discloses a solar cell in which a dielectric layer and a doped layer are sequentially disposed on the second surface of a silicon substrate, and multiple submicron particles are present on the surface of the doped layer away from the dielectric layer. The submicron particles can reduce back reflection of the cell, improve the light absorption capacity of the film layer, and increase the contact area with the metal, thus achieving better contact with the metal.

[0005] To achieve the above objectives, according to a first aspect disclosed in this application, a solar cell is provided, comprising: a silicon substrate having a first surface and a second surface disposed opposite to each other;

[0006] A dielectric layer is disposed on the second surface;

[0007] A doped layer is disposed on the surface of the dielectric layer opposite to the silicon substrate, and the surface of the doped layer opposite to the dielectric layer has a plurality of submicron particles.

[0008] As an optional implementation, the second surface of the silicon substrate includes an N-type passivated conductive contact region, a P-type passivated conductive contact region, and an isolation region. The isolation region is located between the N-type and P-type passivated conductive contact regions. The dielectric layer and the doped layer are disposed within the N-type and P-type passivated conductive contact regions. The N-type passivated conductive contact region is doped with pentavalent elements, such as phosphorus or arsenic, to increase the free electron concentration, giving it conductivity dominated by negative charge carriers. The P-type passivated conductive contact region is doped with trivalent elements, such as boron or gallium, to increase the hole concentration, giving it conductivity dominated by positive charge carriers. The N-type and P-type passivated conductive contact regions have different doping types, forming N-type and P-type semiconductor regions, providing the necessary electric field and channels for carrier separation and transport. The isolation region, located between the N-type and P-type regions, isolates and restricts carrier flow, preventing charge recombination caused by direct contact between different doped regions.

[0009] As an optional implementation, a plurality of the submicron particles are formed on the surface of the doped layer; or,

[0010] Multiple submicron particles are embedded in the doped layer; or,

[0011] A portion of the submicron particles are formed on the surface of the doped layer, and a portion of the submicron particles are embedded in the doped layer.

[0012] As an optional implementation, along a direction perpendicular to the first surface, the submicron particles protrude to a height greater than the thickness of the doped layer. This relationship between particle height and thickness allows for more precise control of light propagation and absorption in the vertical direction, while also optimizing the charge transport path. The relationship between the submicron particle height and the doped layer thickness optimizes the electric field distribution within the battery, which is beneficial for the separation and transport of photogenerated carriers. A larger particle protrusion height can form a more efficient charge collection channel, reducing carrier loss during transport and improving the battery's fill factor and output power.

[0013] As an optional implementation, the submicron particles protrude from the doped layer at a height of 100 nm to 1000 nm along a direction perpendicular to the first surface.

[0014] As an optional implementation, the distribution density of the submicron particles in the doped layer gradually increases from the center of the silicon substrate towards its edges. In the central region of the silicon substrate, the particle density is lower, allowing light to penetrate deeper into the cell, increasing the light propagation path and improving the absorption of long-wavelength light; while in the surrounding regions, the particle density is higher, enabling more effective scattering and absorption of short-wavelength light, reducing light reflection loss, thereby improving light utilization efficiency across the entire wavelength range and enhancing the short-circuit current and photoelectric conversion efficiency of the solar cell.

[0015] As an optional implementation, the submicron particles have a diameter of 100 nm to 1000 nm in the direction parallel to the first surface. Limiting their width in the direction parallel to the first surface can prevent them from being too narrow, which would affect the light reflection effect, and prevent them from being too wide, for example, a single particle that is too wide would affect the contact effect with metal.

[0016] As an optional implementation, both the isolation region and the first surface have a pyramidal texture structure. In the isolation region, this raised structure helps optimize the electric field distribution and reduce carrier recombination; on the first surface, it can effectively improve light incidence and absorption efficiency, working together with other internal structures to enhance the overall performance of the battery.

[0017] As an optional implementation, the doped layer is one of an amorphous silicon layer, a microcrystalline silicon layer, or a polycrystalline silicon layer. Crystalline silicon doped layers have good thermal stability and mechanical strength; amorphous silicon doped layers have good chemical stability and corrosion resistance; microcrystalline silicon doped layers, to some extent, inherit the advantages of both, and can improve the stability and reliability of solar cells under different environmental conditions, thus extending the lifespan of solar cells.

[0018] As an optional implementation, the thickness of the doped layer is 50 nm to 400 nm.

[0019] According to a second aspect disclosed in this application, a photovoltaic module is provided, comprising: the aforementioned solar cell.

[0020] Compared with the prior art, the beneficial effects of this application are:

[0021] The solar cell provided in this application embodiment has a silicon substrate with opposing first and second surfaces. A dielectric layer and a doped layer are sequentially disposed on the second surface. The silicon substrate generates photogenerated carriers, the dielectric layer reduces carrier loss on the surface, and the doped layer promotes carrier separation and transport. The three work together to improve the overall performance of the cell. Furthermore, the roughness of the doped layer can be effectively increased by multiple submicron particles on the surface of the doped layer away from the dielectric layer. The submicron particles can reduce back reflection of the cell, improve the light absorption capacity of the film layer, and increase the contact area with the metal, giving the doped layer better metal contact performance. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the cross-sectional structure of the solar cell disclosed in an embodiment of this application;

[0024] Figure 2 This is a schematic diagram of the structure of the second surface of the solar cell disclosed in the embodiments of this application under a 3D microscope.

[0025] Explanation of reference numerals in the attached figures:

[0026] 100 - Silicon substrate; 11 - First surface; 12 - Second surface; 121 - N-type passivated conductive contact region; 122 - P-type passivated conductive contact region; 123 - Isolation region; 13 - Pyramid texture structure; 200 - Dielectric layer; 300 - Doped layer; 31 - Submicron particles. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] In this application, the terms "upper," "lower," "top," "bottom," "inner," "vertical," and "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0029] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0030] Furthermore, the terms "set up," "equipped with," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0031] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0032] A solar cell is a semiconductor device that directly converts sunlight into electrical energy through the photovoltaic effect.

[0033] With the acceleration of global industrialization, the demand for energy is constantly increasing, while environmental pollution is becoming increasingly serious, prompting people to seek clean and renewable energy alternatives. Solar energy, as an inexhaustible renewable energy source, has advantages such as being pollution-free and emitting no greenhouse gases. In recent years, solar cell technology has made significant progress, with continuously improving conversion efficiency and gradually decreasing manufacturing costs. Therefore, the market demand for solar cells will continue to grow.

[0034] Solar cells work based on the photovoltaic effect of a semiconductor PN junction. When sunlight shines on a semiconductor PN junction, photon energy is absorbed by the semiconductor material, generating electron-hole pairs. These electron-hole pairs are separated under the influence of the built-in electric field of the PN junction; electrons flow to the N-region, and holes flow to the P-region, thus storing excess electrons in the N-region and excess holes in the P-region. An electromotive force is generated in the thin layer between the N-region and the P-region. When an external circuit is connected, current flows through the load, realizing the conversion of light energy into electrical energy.

[0035] In existing technologies, the deposition techniques for amorphous silicon, microcrystalline silicon, or polycrystalline silicon films mainly include low-pressure chemical vapor deposition (LPCVD) and plasma-enhanced chemical vapor deposition (PECVD). Both deposition techniques use silane as the reactive gas. Silane decomposes at high temperatures or under the assistance of an alternating electric field to form a film. Under typical deposition conditions, silane completely decomposes into silicon atoms and hydrogen gas, resulting in a smooth film surface with low roughness. However, this prevents good contact with metals, which is detrimental to light absorption in solar cells.

[0036] Based on this, this application provides a solar cell in which a dielectric layer and a doped layer are sequentially disposed on the second surface of a silicon substrate, and multiple submicron particles are present on the surface of the doped layer away from the dielectric layer. The submicron particles can reduce back reflection of the cell, improve the light absorption capacity of the film layer, and increase the contact area with the metal, thus achieving better contact with the metal.

[0037] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.

[0038] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the cross-sectional structure of the solar cell disclosed in an embodiment of this application. Figure 2 This is a schematic diagram of the structure of the second surface of the solar cell disclosed in this application under a microscope. This application discloses a solar cell comprising: a silicon substrate 100, a dielectric layer 200, and a doped layer 300. The silicon substrate 100 has a first surface 11 and a second surface 12 disposed opposite to each other; the dielectric layer 200 is disposed on the second surface 12; the doped layer 300 is disposed on the surface of the dielectric layer 200 facing away from the silicon substrate 100, and the surface of the doped layer 300 facing away from the dielectric layer 200 has a plurality of submicron particles 31.

[0039] Specifically, the silicon substrate 100, as the basic component of the solar cell, is typically made of high-purity silicon materials, such as monocrystalline silicon or polycrystalline silicon. The silicon substrate 100 has a first surface 11 and a second surface 12 arranged opposite to each other, and its crystal structure is complete, enabling it to absorb sunlight and generate photogenerated carriers.

[0040] A dielectric layer 200 is disposed on the second surface 12 of the silicon substrate 100, and is typically a uniform thin film, such as silicon dioxide or silicon nitride. The dielectric layer 200 can passivate the surface of the silicon substrate 100, reduce surface defects and dangling bonds, and lower the surface recombination rate.

[0041] A doped layer 300 is disposed on the surface of the dielectric layer 200 facing away from the silicon substrate 100. The doped layer 300, by doping with specific impurity elements, forms a suitable electric field and conductivity, promoting the separation and transport of photogenerated carriers. The surface of the doped layer 300 facing away from the dielectric layer 200 has multiple submicron particles 31. Submicron particles 31 refer to particles with a diameter between 100 nm and 1000 nm. For example... Figure 2 As shown, Figure 2 The second surface 12 is magnified, and the black dots are submicron particles 31. Submicron particles 31 can effectively increase the roughness of the doped layer 300, increase its light absorption and scattering, reduce light reflection, change the light propagation path, increase the light travel within the cell, improve the solar cell's light utilization efficiency, and enable the doped layer 300 to form good contact with the metal, and form good ohmic contact with the metal electrode, reducing contact resistance, which is beneficial for charge collection and transfer, reducing charge loss at the contact interface, and improving the electrical performance of the solar cell.

[0042] Solar cells may also include electrodes made of metallic materials for collecting and extracting photocurrent.

[0043] According to an embodiment of the present invention, the solar cell has a silicon substrate 100 with opposing first surfaces 11 and second surfaces 12. A dielectric layer 200 and a doped layer 300 are sequentially disposed on the second surface 12. The silicon substrate 100 generates photogenerated carriers, the dielectric layer 200 reduces carrier loss on the surface, and the doped layer 300 promotes carrier separation and transport. The three work together to improve the overall performance of the cell. Furthermore, the roughness of the doped layer 300 is effectively increased by multiple submicron particles 31 on the surface of the doped layer 300 away from the dielectric layer 200. The submicron particles 31 can reduce back reflection of the cell, improve the light absorption capacity of the film, and increase the contact area with the metal, thus giving the doped layer 300 better metal contact performance.

[0044] Combination Figure 1 In some embodiments, the second surface 12 of the silicon substrate 100 includes an N-type passivated conductive contact region 121, a P-type passivated conductive contact region 122, and an isolation region 123. The isolation region 123 is located between the N-type passivated conductive contact region 121 and the P-type passivated conductive contact region 122. The dielectric layer 200 and the doped layer 300 are disposed in the N-type passivated conductive contact region 121 and the P-type passivated conductive contact region 122.

[0045] Specifically, the N-type passivated conductive contact region 121 is doped with pentavalent elements, such as phosphorus and arsenic, which increases the concentration of free electrons, giving it conductivity dominated by negative charge carriers. The P-type passivated conductive contact region 122 is doped with trivalent elements, such as boron and gallium, which increases the concentration of holes, giving it conductivity dominated by positive charge carriers. The N-type and P-type passivated conductive contact regions 121 and 122 have different doping types, forming N-type and P-type semiconductor regions, providing the necessary electric field and channels for carrier separation and transport. The isolation region 123 is located between the N-type and P-type regions, serving to isolate and restrict carrier flow, preventing charge recombination caused by direct contact between different doped regions. A dielectric layer 200 and a doped layer 300 are then disposed in the N-type passivated conductive contact region 121 and the P-type passivated conductive contact region 122. The doped layer 300 has multiple submicron particles 31 facing away from the surface of the dielectric layer 200, which can effectively increase the roughness of the doped layer 300. The submicron particles 31 can reduce back reflection of the solar cell, improve the light absorption capacity of the film layer, and increase the contact area with the metal, so that the doped layer 300 has better metal contact performance.

[0046] In some embodiments, a plurality of submicron particles 31 are formed on the surface of the doped layer 300; or,

[0047] Multiple submicron particles 31 are embedded in the doped layer 300; or,

[0048] A number of submicron particles 31 are formed on the surface of the doped layer 300, and a number of submicron particles 31 are embedded in the doped layer 300.

[0049] Specifically, the submicron particles 31 can all be formed on the surface of the doped layer 300, or they can all be embedded in the doped layer 300, or a portion of them can be formed on the surface of the doped layer 300 and a portion of them can be embedded in the doped layer 300. Embedding means that a portion of the structure of the submicron particles 31 sinks into the doped layer 300, while another portion is exposed from the surface of the doped layer 300.

[0050] In some embodiments, along a direction perpendicular to the first surface 11, the height of the submicron particles 31 protruding from the doped layer 300 is greater than the thickness of the doped layer 300.

[0051] Specifically, the relationship between particle height and thickness allows for more precise control over light propagation and absorption in the vertical direction, while also optimizing the charge transport path in the vertical direction. The relationship between the height of the submicron particles 31 and the thickness of the doped layer 300 optimizes the electric field distribution inside the battery, which is beneficial for the separation and transport of photogenerated carriers. Larger particle protrusion height can form more efficient charge collection channels, reduce carrier losses during transport, and improve the battery's fill factor and output power.

[0052] In some embodiments, the height of the submicron particles 31 protruding from the doped layer 300 along a direction perpendicular to the first surface 11 is 100 nm to 1000 nm.

[0053] In some embodiments, the thickness of the doped layer 300 is 50 nm to 400 nm.

[0054] In some embodiments, the height of the submicron particles 31 protruding from the doped layer 300 along a direction perpendicular to the first surface 11 is 100 nm to 1000 nm.

[0055] Combination Figure 1 In some embodiments, both the isolation region 123 and the first surface 11 have a pyramid texture structure 13.

[0056] Specifically, the pyramidal texture structure 13 can effectively change the direction of incident light, increasing the propagation path and residence time of light within the battery, thereby improving light absorption efficiency. This effect is particularly significant for short-wavelength light, helping to increase the battery's short-circuit current and improve photoelectric conversion efficiency. This protruding structure can also act as a light scattering mechanism, causing multiple reflections and refractions of light within the battery, enhancing the light-trapping effect. This improves the battery's ability to capture light, allowing more photons to be absorbed by the silicon substrate 100 and converted into photogenerated carriers, further improving battery performance. In some embodiments, the outer surface of the submicron particles 31 is a smooth curved surface.

[0057] Specifically, the submicron particles 31 have smooth curved surfaces with continuous and smooth contours, free of sharp edges or abrupt unevenness, enabling them to effectively reduce light reflection from the solar cell. Due to their smooth surface transition, the incident light is reflected at more dispersed angles on the particle surface, avoiding light loss caused by concentrated reflection. Simultaneously, the curved surface shape allows light to undergo multiple scattering and refraction around the particles, increasing the light propagation path within the cell and thus improving light absorption efficiency. This effect is particularly significant for short-wavelength light, contributing to increased short-circuit current and photoelectric conversion efficiency.

[0058] In some embodiments, the submicron particles 31 are formed by a chemical vapor deposition process.

[0059] Specifically, submicron particles 31 can be formed simultaneously with the doped layer 300 during the chemical vapor deposition process, which can reduce the preparation cost of submicron particles 31 and help maintain the integrity of the particles during battery preparation, packaging and use, avoid performance degradation caused by particle detachment, and extend battery life.

[0060] In some embodiments, the submicron particles 31 are formed from long chains and / or cyclic silane polymers formed by the aggregation of silane groups.

[0061] Specifically, in the fabrication of submicron particles 31, the degree of silane decomposition during the chemical vapor deposition process can be controlled. During the thermal decomposition of silane, the silane is incompletely decomposed to form groups such as silane (SiH), dihydrosilane (SiH2), and trihydrosilane (SiH3); for example, SiH4 → SiH2 + H2. The formed silane groups aggregate together to form long-chain or cyclic silane polymers, ultimately forming submicron particles 31. Moreover, these submicron particles 31 are rich in hydrogen and also have a good passivation effect.

[0062] Chemical vapor deposition (CVD) is a process that utilizes gaseous or vaporous substances to react at the gas phase or gas-solid interface to form solid deposits. It can employ a thermal decomposition reaction, first heating the doped layer 300 to a temperature range of 500℃ to 700℃, preferably 550℃ to 620℃, and then forming a film layer through the thermal decomposition of silane. The partial pressure of silane during deposition can be 150 mTorr to 400 mTorr, preferably 200 mTorr to 350 mTorr, so that the thermal decomposition of silane results in incomplete decomposition, forming groups such as SiH, SiH2, and SiH3.

[0063] In some embodiments, the distribution density of submicron particles 31 in the doped layer 300 gradually increases from the center of the silicon substrate 100 toward its edge.

[0064] Specifically, the distribution density of submicron particles 31 in the doped layer 300 is the number of submicron particles 31 in a certain region. That is, the distribution density of submicron particles 31 gradually increases from the center to the edge of the silicon substrate 100. It can also be said that the distribution characteristics of submicron particles 31 from the center to the edge are increasingly dense. The number of submicron particles 31 at the edge of the silicon substrate 100 is significantly greater than the number of submicron particles at the center of the silicon substrate 100.

[0065] In some embodiments, the particle size of the submicron particles 31 is 100 nm to 1000 nm along a direction parallel to the first surface 11.

[0066] Specifically, the submicron particles 31 are not strictly spherical, but rather irregularly shaped quasi-spherical. The particle size along the direction parallel to the first surface 11 is the maximum width of the submicron particles 31 along the direction parallel to the first surface 11. Limiting the particle size of the submicron particles 31 can prevent their width from being too small, which would affect the light reflection effect, and also prevent their width from being too large, such as a single particle with an excessively large width, which would affect the contact effect with the metal.

[0067] In some embodiments, the doped layer 300 is one of an amorphous silicon layer, a microcrystalline silicon layer, or a polycrystalline silicon layer.

[0068] Specifically, the amorphous silicon layer has an amorphous structure and a wide band gap, exhibiting good absorption capability for short-wavelength light; the microcrystalline silicon layer combines the characteristics of both amorphous and polycrystalline silicon, possessing a certain crystalline structure and larger grain size, enabling it to absorb longer-wavelength light; the polycrystalline silicon layer is composed of multiple small grains, exhibiting high carrier mobility and good electrical properties. Among these, the polycrystalline silicon doped layer 300 exhibits good thermal stability and mechanical strength; the amorphous silicon doped layer 300 exhibits good chemical stability and corrosion resistance; and the microcrystalline silicon doped layer 300, to some extent, inherits the advantages of both, improving the stability and reliability of solar cells under different environmental conditions and extending their lifespan.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A solar cell, characterized in that, include: A silicon substrate (100) having a first surface (11) and a second surface (12) disposed opposite to each other; A dielectric layer (200) is disposed on the second surface (12); A doped layer (300) is disposed on the surface of the dielectric layer (200) away from the silicon substrate (100), and the surface of the doped layer (300) away from the dielectric layer (200) has a plurality of submicron particles (31).

2. The solar cell according to claim 1, characterized in that, The second surface (12) of the silicon substrate (100) includes an N-type passivated conductive contact region (121), a P-type passivated conductive contact region (122), and an isolation region (123). The isolation region (123) is located between the N-type passivated conductive contact region (121) and the P-type passivated conductive contact region (122). The dielectric layer (200) and the doped layer (300) are disposed in the N-type passivated conductive contact region (121) and the P-type passivated conductive contact region (122).

3. The solar cell according to claim 1, characterized in that, Multiple submicron particles (31) are formed on the surface of the doped layer (300); or, Multiple submicron particles (31) are embedded in the doped layer (300); or, A portion of the submicron particles (31) are formed on the surface of the doped layer (300), and a portion of the submicron particles (31) are embedded in the doped layer (300).

4. The solar cell according to claim 1, characterized in that, Along a direction perpendicular to the first surface (11), the submicron particles (31) protrude from the doped layer (300) at a height greater than the thickness of the doped layer (300).

5. The solar cell according to claim 4, characterized in that, Along a direction perpendicular to the first surface (11), the submicron particles (31) protrude from the doped layer (300) at a height of 100 nm to 1000 nm.

6. The solar cell according to claim 1, characterized in that, Along a direction parallel to the first surface (11), the particle size of the submicron particles (31) is 100 nm to 1000 nm.

7. The solar cell according to claim 2, characterized in that, The distribution density of the submicron particles (31) on the doped layer (300) gradually increases from the center of the silicon substrate (100) toward its edge.

8. The solar cell according to claim 1, characterized in that, The doped layer (300) is one of an amorphous silicon layer, a microcrystalline silicon layer, or a polycrystalline silicon layer.

9. The solar cell according to claim 1, characterized in that, The thickness of the doped layer (300) is 50 nm to 400 nm.

10. A photovoltaic module, characterized in that, include: The solar cell as described in any one of claims 1-9.

Images