Metal-semiconductor contact structure, solar cell and photovoltaic module

Abstract

The invention relates to the field of solar cells, in particular to a metal-semiconductor contact structure, a solar cell and a photovoltaic module. The metal-semiconductor contact structure comprises a doped semiconductor layer with a pyramid structure on the surface and a metal electrode in contact with the doped semiconductor layer; a contact area of the doped semiconductor layer and the metal electrode comprises a first contact area, and a plurality of first conductive microstructures are arranged in the first contact area; the first conductive microstructure is located between the metal electrode and the pyramid structure, the first conductive microstructure is arranged on the pyramid structure with the flat surface, particles of the first conductive microstructure are eutectic particles composed of metal elements and semiconductor elements, the metal elements are the same as the metal elements in the metal electrode, and the semiconductor elements are different from the metal elements in the metal electrode. The semiconductor element is the same as a main semiconductor element in the doped semiconductor layer; wherein the distribution density of the first conductive microstructures on the pyramid structure is in a decreasing change trend in the direction from the tower tip of the pyramid structure to the tower bottom of the pyramid structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a gold half contact structure, a solar cell and a photovoltaic module. BACKGROUND

[0002] In the field of solar cells, the gold half contact structure has an important influence on the photoelectric performance of the solar cell. However, when the gold half contact structure includes a doped semiconductor layer with a gold pyramid structure on the surface, the structural morphology at the contact interface between the metal electrode and the gold pyramid structure is not ideal, which can easily cause metal recombination loss, surface recombination loss and other problems. It can be seen that the structural morphology at the contact interface of such a gold half contact structure still needs to be further optimized to more effectively improve the contact performance between the metal electrode and the doped semiconductor layer and improve the photoelectric conversion efficiency of the solar cell. SUMMARY

[0003] In order to solve the above technical problems, the present application discloses a gold half contact structure, a solar cell and a photovoltaic module to more effectively improve the contact performance of the gold half contact structure and thereby improve the photoelectric conversion efficiency of the solar cell.

[0004] In a first aspect, the present application provides a gold half contact structure, which comprises:

[0005] a doped semiconductor layer, the surface of the doped semiconductor layer being a gold pyramid structure surface;

[0006] a metal electrode in contact with the doped semiconductor layer;

[0007] The contact area between the doped semiconductor layer and the metal electrode includes a first contact area, and the first contact area has a plurality of first conductive microstructures;

[0008] The first conductive microstructure is located between the metal electrode and the gold pyramid structure, and the first conductive microstructure is arranged on the gold pyramid structure with a flat surface. The particles of the first conductive microstructure are eutectic particles composed of a metal element and a semiconductor element. The metal element is the same as the metal element in the metal electrode, and the semiconductor element is the same as the main semiconductor element in the doped semiconductor layer.

[0009] The distribution density of the first conductive microstructure on the gold pyramid structure decreases from the top of the pyramid to the bottom of the pyramid.

[0010] Further, the particle size of the eutectic particles is 10-200 nm; and / or,

[0011] The number of the eutectic particles in any 10 μm x 10 μm area of the first contact area is 100-1500; and / or,

[0012] The first conductive microstructures are distributed on the surface of the pyramid structure with a spacing and are dispersedly distributed on the surface of the pyramid structure; and / or,

[0013] At least part of the first conductive microstructures are distributed in a conical shape on the pyramid structure.

[0014] Further, the side length of the base of the pyramid structure ranges from 0.35 μm to 2.5 μm; and / or,

[0015] The diagonal of the base of the pyramid structure ranges from 0.5 μm to 3.5 μm.

[0016] Further, the pyramid structure comprises a plurality of first type pyramid structures and a plurality of second type pyramid structures distributed between the first type pyramid structures;

[0017] The diagonal of the base of the first type pyramid structure ranges from 1.5 μm to 3.5 μm, and the diagonal of the base of the second type pyramid structure ranges from 0.5 μm to 1.5 μm.

[0018] Further, the first conductive microstructures have a first distribution area and a second distribution area on the surface of the first type pyramid structure, in the first distribution area, the distribution density of the first conductive microstructures is 100 / μm 2 -400 / μm 2 , in the second distribution area, the distribution density of the first conductive microstructures is 20 / μm 2 -100 / μm 2 , and the distribution of the first conductive microstructures in the first distribution area is denser than that in the second distribution area; wherein the slant edge length of the pyramid structure is L, the area with a radius less than or equal to R centered on the top of the pyramid structure is the first distribution area, and the surface of the pyramid structure outside the first distribution area is the second distribution area, R / L≤2:3;

[0019] The distribution density of the first conductive microstructures on the surface of the second type pyramid structure is 30 / μm 2 -100 / μm 2 .

[0020] Further, the contact area of the doped semiconductor layer and the metal electrode further comprises a second contact area, the second contact area is located outside the first contact area, and the second contact area has a plurality of second conductive microstructures.

[0021] The second conductive microstructure is wrapped in the glass phase of the metal electrode, and the second conductive microstructure is metal elemental particles, which are the same as the metal elements in the metal electrode.

[0022] Further, in a preset area of the contact area, the area ratio of the second contact area to the preset area is 1:5-1:3; wherein the preset area is an area with a preset width and a preset length, which is centered on the middle line of the width of the metal electrode, the preset width is perpendicular to the direction of the width of the metal electrode, and the preset width is less than or equal to 23 μm; the preset length is parallel to the direction of the width of the metal electrode, and the preset length is less than or equal to 16 μm.

[0023] Further, the doped semiconductor layer includes at least one of a doped amorphous silicon layer, a doped polysilicon layer, a doped microcrystalline silicon layer, or a doped crystalline silicon layer; and / or,

[0024] The doping element in the doped semiconductor layer includes at least one of an N-type conductive element or a P-type conductive element; and / or,

[0025] The metal element includes at least one of a silver element, a lead element, a copper element, an aluminum element, a nickel element, a cadmium element, or a bismuth element.

[0026] In a second aspect, the embodiments of the present application provide a solar cell, which includes a silicon substrate and a metal-semiconductor contact structure on the silicon substrate, the metal-semiconductor contact structure including:

[0027] A doped semiconductor layer, which is arranged on the surface of the silicon substrate, and the surface away from the silicon substrate of the doped semiconductor layer is a pyramidal structure surface;

[0028] A metal electrode, which is arranged on the side of the doped semiconductor layer away from the silicon substrate, and the metal electrode and the doped semiconductor layer are in contact with each other;

[0029] The contact area of the doped semiconductor layer and the metal electrode includes a first contact area, and the first contact area has a plurality of first conductive microstructures;

[0030] The first conductive microstructure is located between the metal electrode and the pyramidal structure, and the first conductive microstructure is arranged on the pyramidal structure with a flat surface, the particles of the first conductive microstructure are eutectic particles composed of a metal element and a semiconductor element, the metal element is the same as the metal element in the metal electrode, and the semiconductor element is the same as the main semiconductor element in the doped semiconductor layer;

[0031] The distribution density of the first conductive microstructure on the pyramid structure presents a decreasing change trend from the top of the pyramid structure to the bottom of the pyramid structure.

[0032] Further, the solar cell comprises:

[0033] The first doped semiconductor layer is opposite to the conductive type of the silicon substrate.

[0034] The back surface of the silicon substrate is sequentially provided with a passivation contact structure, a second passivation layer and a second metal electrode in the direction away from the back surface, wherein the passivation contact structure comprises a dielectric layer close to the silicon substrate and a second doped semiconductor layer away from the silicon substrate, the second doped semiconductor layer is of the same conductive type as the silicon substrate, and the second metal electrode is in ohmic contact with the second doped semiconductor layer through the second passivation layer.

[0035] Further, the first doped semiconductor layer is formed by thermal diffusion of a doping element to the silicon substrate, or the first doped semiconductor layer is a doped polysilicon layer or a doped amorphous silicon layer deposited on the light-receiving surface of the silicon substrate; and / or,

[0036] The first passivation layer is one or more of an aluminum oxide layer, a silicon oxide layer, a silicon oxynitride layer or a silicon nitride layer deposited on the PN junction region; and / or,

[0037] The dielectric layer is at least one of a silicon oxide layer, an amorphous silicon layer, a polysilicon layer and a silicon carbide layer; and / or,

[0038] The second passivation layer is one or more of a silicon oxide layer, a silicon oxynitride layer or a silicon nitride layer deposited on the second doped semiconductor layer.

[0039] In a third aspect, an embodiment of the present application provides a photovoltaic module, which comprises the solar cell of the third aspect, and a plurality of the solar cells are connected in series and / or in parallel to obtain a solar cell string.

[0040] An encapsulation structure, and the solar cell string is encapsulated in the encapsulation structure.

[0041] Compared with the prior art, the present application has at least the following beneficial effects:

[0042] The gold-semi contact structure is provided in the embodiments of the present application, which can improve the mechanical structural stability of the contact interface between the doped semiconductor layer and the metal electrode, and obtain more stable and reliable first conductive microstructures, and promote the improvement of the carrier transport capacity. On the other hand, due to the special distribution characteristics of the first conductive microstructures on the pyramid structure, the problems such as metal recombination and defect damage caused by recombination can be reduced. The ohmic contact performance between the doped semiconductor layer with a pyramid-shaped contact surface and the metal electrode is improved through the above two aspects, and the photoelectric conversion efficiency of the solar cell is further effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the 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 is a structural schematic diagram of a solar cell in the embodiments of the present application;

[0045] Figure 2 is Figure 1 is an enlarged schematic diagram of the structure at A in

[0046] Figure 3 is a schematic diagram of the distribution of the first conductive microstructure on the pyramid structure;

[0047] Figure 4 is a schematic diagram of the structural characteristics of the surface of the doped semiconductor layer in different gold-semi contact structures;

[0048] Figure 5 is an SEM image of an untreated bare silicon substrate;

[0049] Figure 6 is an SEM image of the doped semiconductor layer in the gold-semi contact structure of the embodiments of the present application, which has the first conductive microstructure distributed thereon;

[0050] Figure 7 is an SEM image of the doped semiconductor layer in the gold-semi contact structure of the embodiments of the present application, which has the first conductive microstructure distributed thereon (under another magnification);

[0051] Figure 8 is an SEM image of the doped semiconductor layer in the gold-semi contact structure of the embodiments of the present application, which has the first conductive microstructure distributed thereon (under another magnification);

[0052] Figure 9 is an SEM image of the doped semiconductor layer in the gold-semi contact structure of the embodiments of the present application, which has the first conductive microstructure distributed thereon (under another magnification);

[0053] Reference numerals:

[0054] 1 silicon substrate; 2 doped semiconductor layer; 200 pyramid structure; 201 first type of pyramid structure; 202 second type of pyramid structure; 21 first doped semiconductor layer; 22 second doped semiconductor layer; 3 metal electrode; 31 first metal electrode; 32 second metal electrode; 4 passivation layer; 41 first passivation layer; 42 second passivation layer; 5 dielectric layer; 100 metal-semiconductor contact structure; 100a first contact region; 101 first conductive microstructure. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0056] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0057] In addition, in addition to indicating the orientation or positional relationship, the above-mentioned part of the terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For a person of ordinary skill in the art, the specific meaning of these terms in the present application can be understood according to the specific situation.

[0058] In addition, the terms "mount", "set", "provided with", "connect", "connected" should be broadly understood. For example, it can be fixedly connected, detachably connected, or integrally constructed; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or internal communication between two devices, elements or components. For a person of ordinary skill in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific situation.

[0059] In addition, the terms "first", "second" and the like are used merely to distinguish different devices, elements or components (which can be identical or different), and are not intended to imply relative importance or significance of the indicated devices, elements or components. Unless otherwise specified, the meaning of "a plurality" is two or more.

[0060] In a first aspect, in combination with Figures 1 to 3 as shown, Figure 1 A solar cell with a metal-semiconductor contact structure, Figure 2 is Figure 1 is an enlarged schematic view of the structure at A, Figure 3 is a schematic view of the distribution of the first conductive microstructure on the pyramidal structure. Embodiments of the present application provide a metal-semiconductor contact structure, which is applied to a solar cell, the solar cell comprising:

[0061] a silicon substrate 1;

[0062] a doped semiconductor layer 2, which is arranged on the silicon substrate 1;

[0063] a metal electrode 3, which is in contact with the doped semiconductor layer 2.

[0064] The metal electrode 3 and the doped semiconductor layer 2 form a metal-semiconductor contact structure 100. The contact between the metal electrode 3 and the doped semiconductor layer 2 is a physical contact, i.e. the structures of the two are directly in contact.

[0065] The metal-semiconductor contact structure 100 will be described below.

[0066] The metal-semiconductor contact structure 100 comprises:

[0067] a doped semiconductor layer 2, a surface of the doped semiconductor layer 2 being a surface of a pyramidal structure 200;

[0068] a metal electrode 3, which is in contact with the doped semiconductor layer 2.

[0069] The contact area between the doped semiconductor layer 2 and the metal electrode 3 comprises a first contact area 100a, and the first contact area 100a has a plurality of first conductive microstructures 101;

[0070] The first conductive microstructure 101 is located between the metal electrode 3 and the contact surface, and the first conductive microstructure 101 is arranged on the pyramidal structure 200 with a flat surface. The first conductive microstructure 101 is a eutectic particle composed of a metal element and a semiconductor element. The metal element is the same as the metal element in the metal electrode 3, and the semiconductor element is the same as the main semiconductor element in the doped semiconductor layer 2.

[0071] The distribution density of the first conductive microstructure 101 on the pyramid structure 200 decreases from the top of the pyramid structure 200 to the bottom of the pyramid structure 200.

[0072] The surface of the doped semiconductor layer 2 is in the shape of a pyramid, that is, the surface of the doped semiconductor layer 2 is composed of a plurality of pyramid structures 200, and the surface of the doped semiconductor layer 2 is in the shape of a pyramid as a whole.

[0073] For a solar cell, the surface of the silicon substrate 1 can be changed into a pyramid-shaped surface by means of texturing, and the doped polysilicon layer is on the silicon substrate 1. The doped semiconductor layer 2 can be a film layer deposited on the silicon substrate 1, for example, a boron-doped polysilicon layer formed on the silicon substrate 1 by means of PECVD process as the doped semiconductor layer 2. In this case, the surface of the doped semiconductor layer 2 is the surface of the doped semiconductor layer 2 away from the silicon substrate 1, which is arranged in the same shape as the silicon substrate 1, so the surface of the doped polysilicon layer is in the same or similar shape as the surface of the silicon substrate 1. Alternatively, in other embodiments, the doped semiconductor layer 2 can be a diffusion layer formed by diffusing semiconductor conductive elements from the surface of the silicon substrate 1 into the silicon substrate 1, for example, a boron diffusion layer formed by high-temperature boron diffusion on the surface of the silicon substrate 1 as the doped polysilicon layer. In this case, the surface of the doped semiconductor layer 2 is actually the surface of the silicon substrate 1 into which the semiconductor conductive elements are diffused. In this case, since the surface of the silicon substrate 1 is changed into the doped semiconductor layer 2 after diffusion, the surface of the silicon substrate 1 before diffusion is in the shape of a pyramid, and after the silicon substrate 1 is diffused to form the doped semiconductor layer 2, the surface of the doped semiconductor layer 2 for contacting the metal electrode 3 is also in the shape of a pyramid.

[0074] The first conductive microstructure 101 is arranged on the surface of the pyramid structure 200, that is, although the surface of the doped semiconductor layer 2 is composed of a plurality of pyramid structures 200 and is in the shape of a pyramid as a whole, the pyramid structures 200 have no obvious structural damage such as holes and pits, so that most or all of the surface of the doped semiconductor layer 2 (for example, the top of the pyramid and the side of the pyramid) is flat and has a high degree of structural integrity. Figure 4 Figure 4 The surface of the doped semiconductor layer 2 has different states, as shown in the structural schematic diagram. Figure 4 (a) is a schematic diagram of the flat surface of the doped semiconductor layer 2, which is also the surface structure feature of the doped semiconductor layer 2 in the embodiments of the present application. Figure 4 ​(b) is a schematic diagram of the surface of the doped semiconductor layer 2 on which large pits are formed on the side of the pyramids, Figure 4 (c) is a schematic diagram of the surface of the doped semiconductor layer 2 on which the tips of the pyramids are corroded, Figure 4 (b) and Figure 4 (c) are structural features of the surface of the doped semiconductor layer 2 in the prior art gold-semiconductor contact structure 100.

[0075] For comparison, see the untreated bare silicon substrate 1 shown in Figure 5 , Figure 5 The scanning electron microscope image of the untreated bare silicon substrate 1 is shown, from which it can be seen that before being treated by printing and sintering electrode paste, etc., the surface of the silicon substrate 1 presents a pyramidal shape, and the tips and side surfaces of the pyramids, etc., all remain in a relatively high degree of integrity. See Figure 6 and Figure 7 , Figure 6 and Figure 7 The scanning electron microscope image of the distribution of the first conductive microstructure 101 on the doped semiconductor layer 2 in the gold-semiconductor contact structure 100 of an embodiment of the present application is shown, wherein the doped semiconductor layer 2 is obtained by diffusing a doped semiconductor conductive element on the silicon substrate 1, and thus can be compared with the surface structure of the bare silicon substrate 1, in addition Figure 7 and Figure 6 have different magnifications, Figure 7 50K magnification is shown. By comparison, it can be seen that although the first conductive microstructure 101 in the embodiment of the present application is arranged on the pyramidal structure 200, it does not destroy the flatness of the surface of the doped polysilicon layer, and the surface of most areas remains in a good pyramidal shape, the tips of the pyramids do not have obvious holes or corrosion, and the side surfaces of the pyramids do not have a large number of pit damages.

[0076] The first conductive microstructure 101 is a eutectic particle composed of a metal element and a semiconductor element, the metal element of the first conductive microstructure 101 is the same as the metal element in the metal electrode 3, and the semiconductor element in the first conductive microstructure 101 is the same as the main semiconductor element in the doped semiconductor layer 2. That is, the first conductive microstructure 101 as a eutectic structure, its semiconductor element comes from the doped semiconductor layer 2, and its metal element comes from the metal electrode 3. In addition, the main semiconductor element in the doped semiconductor layer 2 refers to the semiconductor element as the main component in the doped semiconductor layer 2, rather than the doping element for enhancing the conductivity of the semiconductor layer.

[0077] Optionally, the metal element includes at least one of a silver element, a lead element, a copper element, an aluminum element, a nickel element, a cadmium element or a bismuth element. Preferably, the metal electrode 3 is a silver electrode, and the metal element includes a silver element. Optionally, the doped semiconductor layer 2 includes at least one of a doped amorphous silicon layer, a doped polysilicon layer, a doped microcrystalline silicon layer or a doped monocrystalline silicon layer. Optionally, the doping element in the doped semiconductor layer 2 includes at least one of an N-type conductive element or a P-type conductive element, the N-type conductive element includes, for example, a phosphorus element, an antimony element or an arsenic element, and the P-type conductive element includes, for example, a boron element, a gallium element or an indium element. Exemplarily, the metal electrode 3 is a silver electrode, and the doped semiconductor layer 2 is a boron-doped polysilicon layer, and in the doped semiconductor layer 2, the main semiconductor element is a silicon element, the doping element is a boron element, and the first conductive microstructure 101 is a silver-silicon eutectic structure formed by chemical bonding between the silver element and the silicon element.

[0078] In the pyramid structure 200, the distribution density of the first conductive microstructure 101 on the pyramid structure 200 decreases from the top of the pyramid structure 200 to the bottom of the pyramid structure 200. This indicates that in the embodiment of the present application, the first conductive microstructure 101 is more concentrated in the region close to the top of the pyramid, and there are fewer first conductive microstructures 101 in the region close to the bottom of the pyramid.

[0079] The gold-semiconductor contact structure 100 can improve the ohmic contact performance between the doped semiconductor layer 2 with a pyramid shape and the metal electrode 3 from two aspects of improving the carrier transport capacity and reducing the recombination phenomenon, thereby effectively improving the photoelectric conversion efficiency of the solar cell.

[0080] Firstly, the gold-semiconductor contact structure 100 has a carrier transport structure with more stable structure, which can effectively improve the carrier transport capacity. Compared with the metal silver particles or silver single-element crystals simply attached to the pyramid structure 200, the eutectic particles in the embodiment of the present application are formed by chemical bonding between the main semiconductor element in the doped semiconductor layer 2 and the metal element in the metal electrode 3, so the eutectic particles have stronger adhesion and more reliable adhesion structure, thereby providing a more stable ohmic contact structure, improving the mechanical bonding force of the gold-semiconductor contact interface, and further improving the carrier transport capacity.

[0081] Secondly, the gold-semi contact structure 100 of the embodiment of the present application can not only improve the recombination phenomenon caused by defect damage, but also improve the metal recombination phenomenon. On the one hand, although the first conductive microstructure 101 is formed on the pyramid structure 200, the pyramid structure 200 as a whole still has the structure characteristics of a flat surface, neither a large-area corrosion pit is formed at the position of the pyramid side or near the top of the pyramid, nor an obvious hole damage is formed at the top of the pyramid or near the top of the pyramid. The pyramid structure 200 has high integrity and small damage degree, so that the defect recombination problem caused by the structure damage of the pyramid structure 200 is greatly reduced.

[0082] On the other hand, the first conductive microstructure 101 adopted in the embodiment of the present application has a unique distribution characteristic on the surface of the pyramid shape, that is, the first conductive microstructure 101 is more distributed near the top of the pyramid, and is more sparse near the bottom of the pyramid. Since most of the first conductive microstructure 101 is more concentrated near the top of the pyramid, the contact area of the pyramid side at this position with the metal electrode 3 is relatively small, so there is less metal recombination; although the closer to the bottom of the pyramid, the larger the contact area of the pyramid side with the metal electrode 3, but the first conductive microstructure 101 in this region is relatively less, so there is also less metal recombination. As can be seen from the above distribution characteristics of the embodiment of the present application, the first conductive microstructure 101 can not only ensure a sufficient number of first conductive microstructure 101 for improving the carrier transport capability, but also can more effectively reduce the metal recombination.

[0083] Further, referring back to FIG. 1, Figure 6 It can be seen from the dotted box area of FIG. 1 that at least part of the first conductive microstructure 101 is distributed in a conical shape on the pyramid structure 200. From the perspective of the pyramid structure 200, Figure 6 It can be seen from the dotted box area of FIG. 1 that at least part of the first conductive microstructure 101 is distributed in a conical shape on the pyramid structure 200. From the perspective of the pyramid structure 200,

[0084] Further, referring back to FIG. 1, Figure 7 It can be seen from the dotted box area of FIG. 1 that at least part of the first conductive microstructure 101 is distributed in a conical shape on the pyramid structure 200. From the perspective of the pyramid structure 200,

[0085] Further, the eutectic particles have a size in the range of 10 nm to 200 nm. Illustratively, the eutectic particles have a size of 10 nm, 20 nm, 50 nm, 80 nm, 100 nm, 120 nm, 150 nm, 180 nm or 200 nm.

[0086] Further, in any 10 μm x 10 μm area of the first contact region 100a, the number of eutectic particles is in the range of 100 to 1500. Illustratively, in any 10 μm x 10 μm area of the first contact region 100a, the number of eutectic particles is 100, 200, 500, 600, 800 or 1000. The size and number of eutectic particles in the above range are advantageous to better avoid the agglomeration of the first conductive microstructure 101, and to further reduce the contact resistance and improve the fill factor.

[0087] Further, the base of the pyramid structure 200 has a side length in the range of 0.35 μm to 2.5 μm, and a diagonal line in the range of 0.5 μm to 3.5 μm. The side length and the diagonal line of the base of the pyramid structure 200 in the above range indicate that the overall size of the pyramid structure 200 is small, which belongs to a small-size pyramid base. In such a small-size pyramid base, the first conductive microstructure 101 in a conical shape is mainly distributed in the area close to the pyramid tip, indicating that there is no large-area continuous cluster conductive structure (such as a large-area continuous silver block or silver spot) in contact with the pyramid structure 200 of the doped semiconductor layer 2. Such a structure is advantageous to reduce the metallization recombination of the metal-semiconductor contact structure 100 and to increase the open-circuit voltage.

[0088] Further, referring to Figure 9 , the pyramid structure 200 includes a plurality of first-type pyramid structures 201 and a plurality of second-type pyramid structures 202 distributed between the first-type pyramid structures 201. The base of the first-type pyramid structure 201 has a diagonal line in the range of 1.5 μm to 3.5 μm, and the base of the second-type pyramid structure 202 has a diagonal line in the range of 0.5 μm to 1.5 μm. On the basis of the small-size feature of the pyramid structure 200 as a whole, the first-type pyramid structure 201 has a relatively large size, the second-type pyramid structure 202 has a relatively small size, and the second-type pyramid structure 202 is distributed between the first-type pyramid structures 201, which can more fully utilize the space in the area close to the base of the first-type pyramid structure 201, provide more uneven surface structures, and increase the surface area of the pyramid structure 200. Such a structure arrangement can improve the light utilization rate, and provide more area of the pyramid tip and the pyramid side surface near the pyramid tip for more first conductive microstructures 101 to adhere to, further improve the carrier transport capability and the mechanical bonding strength of the metal-semiconductor contact interface.

[0089] Further, the first conductive microstructure 101 has a first distribution area and a second distribution area on the surface of the first type of pyramid structure 201. In the first distribution area, the distribution density of the first conductive microstructure 101 is 100 / μm 2 ~400 / μm 2 In the second distribution area, the distribution density of the first conductive microstructure 101 is 20 / μm 2 ~100 / μm 2 , and the distribution of the first conductive microstructure 101 in the first distribution area is denser than that in the second distribution area; wherein the slope side length of the pyramid structure 200 is L, and the area with a radius less than or equal to R centered on the tip of the pyramid structure 200 is the first distribution area, and the surface of the pyramid structure 200 outside the first distribution area is the second distribution area, R / L≤2:3.

[0090] The distribution density of the first conductive microstructure 101 on the surface of the second type of pyramid structure 202 is 30 / μm 2 ~100 / μm 2 .

[0091] The distribution density of the first conductive microstructure 101 on the surface of the first type of pyramid structure 201 and the second type of pyramid structure 202 is controlled within the above range, the number of the first conductive microstructure 101 is sufficient, the adhesion of the first conductive microstructure 101 to the pyramid structure 200 is stronger, and the contact area with the metal electrode 3 is small, which is beneficial to better improve the carrier capacity while greatly reducing the metallization recombination.

[0092] In addition to the first contact area 100a, the contact area between the doped semiconductor layer 2 and the metal electrode 3 also includes a second contact area, the second contact area is located outside the first contact area 100a, and the second contact area has a plurality of second conductive microstructures; the second conductive microstructure is wrapped in the glass phase of the metal electrode 3, the second conductive microstructure is a metal single particle, and the metal single particle is the same as the metal element in the metal electrode 3. For example, the metal electrode 3 is a silver electrode, and the second conductive microstructure is a silver single particle.

[0093] Further, in the preset area of the contact area, the area ratio of the second contact area to the preset area is 1:5-1:3; wherein the preset area is an area with a preset width and a preset length, with the center line of the width of the metal electrode 3 as the center, the preset width is perpendicular to the direction of the width of the metal electrode 3, and the preset width is less than or equal to 23 μm; the preset length is parallel to the direction of the width of the metal electrode 3, and the preset length is less than or equal to 16 μm. The area ratio of the second contact area (i.e. the area where the metal single particle is located) to the preset area is in the above range, that is, the area ratio of the first contact area 100a (i.e. the area where the eutectic particle is located) in the preset area is larger, which is beneficial to more effectively improve the contact performance and reduce the problem of recombination.

[0094] It can be understood that the metal electrode 3 in the embodiment of the application refers to the electrode used for contacting the doped semiconductor layer 2. For example, the collector electrode directly contacts the doped semiconductor layer, and the bus electrode does not directly contact the doped semiconductor layer, and the collector electrode and the doped semiconductor layer have a contact area, and at this time, the metal electrode 3 refers to the auxiliary gate electrode.

[0095] The embodiment of the application also provides a preparation method of the above-mentioned metal-semiconductor contact structure, comprising the following steps:

[0096] Printing electrode paste on the doped semiconductor layer; wherein the electrode paste comprises glass frit, metal particles and organic carrier;

[0097] Sintering in stages:

[0098] First stage heating: low-temperature drying of the electrode paste to form an electrode precursor on the doped semiconductor layer, the electrode precursor comprising glass frit distributed on the surface of the pyramid structure and metal particles wrapped in the glass frit; the sintering temperature of the low-temperature drying is less than the peak sintering temperature of the electrode paste;

[0099] Second stage heating: controlling the heating rate to be 30-45 ℃ / s to reach the peak sintering temperature of the electrode paste, so that the surface of the pyramid structure is flat;

[0100] Applying a reverse bias voltage to the electrode precursor and simultaneously performing laser-induced contact treatment to form a metal electrode and form eutectic particles on the flat-surfaced pyramid structure.

[0101] In the above preparation method, after printing the electrode paste, the electrode paste is first dried and sintered in stages, and the heating rate of the second stage is controlled to ensure that the pyramid structure remains relatively flat and maintains a high degree of structural integrity after sintering, and will not be damaged by glass phase ablation at the pyramid tip or side. Then, by applying a reverse bias voltage and laser-induced contact treatment, the main semiconductor elements in the doped semiconductor layer and the metal elements in the metal electrode form eutectic particles through chemical bonding, thereby obtaining a gold-semiconductor contact structure with better contact performance and stronger mechanical bonding ability at the gold-semiconductor contact interface.

[0102] Furthermore, a passivation layer is provided on the doped semiconductor layer, and the electrode paste is printed on the passivation layer;

[0103] In the first stage of heating, the electrode slurry is dried at low temperature to form an electrode precursor on the passivation layer.

[0104] In the second stage of heating, the heating rate is controlled at 30℃ / min to 45℃ / min until the sintering temperature reaches the peak sintering temperature of the electrode slurry, so that the electrode precursor only burns through the passivation layer and the surface of the pyramid structure 200 is smooth.

[0105] The preparation method also includes performing laser-induced contact treatment followed by light injection to form a metal electrode.

[0106] By controlling the heating rate of the second stage, the corrosion rate of the passivation layer by the glass material can be better controlled, thus avoiding severe corrosion of the pyramid structure of the doped semiconductor layer by the glass phase.

[0107] Furthermore, the conditions for the first stage of heating include: a heating temperature of 250℃~350℃ and a heating time of 5s~20s.

[0108] Furthermore, the conditions for the second stage of heating include: a heating temperature of 700℃~800℃ and a heating time of 10s~20s.

[0109] It should be noted that the above-described solar cell fabrication process is only one optional implementation method. The gold-semiconductor contact structure of the present application embodiment can also be obtained through other process technologies in the field, and the present application does not limit this.

[0110] Furthermore, the gold-semiconductor contact structure of this application embodiment can be applied to various types of solar cells. Optionally, the solar cell includes PERC cell, HJT cell, TOPCon cell, IBC cell, or perovskite-crystalline silicon tandem solar cell.

[0111] See also Figure 1 This is a type of solar cell suitable for the gold-semiconductor contact structure 100. Specifically, this solar cell includes:

[0112] a silicon substrate 1;

[0113] On the light-receiving surface of the silicon substrate 1, a first doped semiconductor layer 21, a first passivation layer 41 and a first metal electrode 31 are sequentially arranged in a direction away from the light-receiving surface, the first doped semiconductor layer 21 is opposite to the conductive type of the silicon substrate 1; the first metal electrode 31 contacts the first doped semiconductor layer 21 through the first passivation layer 41, so that the first doped semiconductor layer 21 and the first metal electrode 31 form a Schottky contact structure 100;

[0114] On the back surface of the silicon substrate 1, a passivation contact structure, a second passivation layer 42 and a second metal electrode 32 are sequentially arranged in a direction away from the back surface, wherein the passivation contact structure comprises a dielectric layer 5 arranged close to the silicon substrate 1 and a second doped semiconductor layer 22 arranged away from the silicon substrate 1, the second doped semiconductor layer 22 is the same as the conductive type of the silicon substrate 1; the second metal electrode 32 is in ohmic contact with the second doped semiconductor layer 22 through the second passivation layer 42.

[0115] Optionally, the first doped semiconductor layer 21 is formed by thermal diffusion of a doping element to the silicon substrate 1, or the first doped semiconductor layer 21 is a doped polysilicon layer or a doped amorphous silicon layer deposited on the light-receiving surface of the silicon substrate 1. Optionally, the first passivation layer 41 is one or more of an aluminum oxide layer, a silicon oxide layer, a silicon oxynitride layer or a silicon nitride layer deposited on the PN junction region. Optionally, the dielectric layer 5 is at least one of a silicon oxide layer, an amorphous silicon layer, a polysilicon layer or a silicon carbide layer. Optionally, the second passivation layer 42 is one or more of a silicon oxide layer, a silicon oxynitride layer or a silicon nitride layer deposited on the second doped semiconductor layer 22.

[0116] It should be noted that, since Figure 1 the light-receiving surface of the silicon substrate 1 is a pyramid structure, the first doped semiconductor layer 21 and the first metal electrode 31 on the light-receiving surface side can form a first conductive microstructure, and the Schottky contact structure 100 has a specific distribution density variation trend on the pyramid structure. While Figure 1 the back surface of the silicon substrate 1 is a plane, the second metal electrode 32 and the second doped semiconductor layer 22 are in ohmic contact, but do not form a Schottky contact structure with the same conductive microstructure characteristics as the light-receiving surface.

[0117] In a second aspect, the embodiments of the present application provide a photovoltaic module, which comprises the solar cell of the first aspect, and a plurality of solar cells are connected in series and / or parallel to obtain a solar cell string.

[0118] a packaging structure, and the solar cell string is packaged in the packaging structure.

[0119] The present application will be further described in conjunction with more specific embodiments.

[0120] Embodiment 1

[0121] The embodiment provides a solar cell with a gold-semiconductor contact structure, comprising:

[0122] An N-type silicon substrate, a light-receiving surface of the N-type silicon substrate being a pyramid-shaped surface;

[0123] A boron diffusion layer, an aluminum oxide passivation layer, a silicon nitride anti-reflection layer and a first metal electrode are sequentially arranged on the light-receiving surface of the N-type silicon substrate, the first metal electrode is in contact with the boron diffusion layer after passing through the silicon nitride anti-reflection layer and the aluminum oxide passivation layer, and the first metal electrode and the boron diffusion layer form a gold-semiconductor contact structure;

[0124] A silicon oxide dielectric layer, a phosphorus-doped polysilicon layer, a silicon nitride passivation layer and a second metal electrode are sequentially arranged on a back surface of the N-type silicon substrate, and the second metal electrode is in ohmic contact with the phosphorus-doped polysilicon layer after passing through the silicon nitride passivation layer.

[0125] The boron diffusion layer has a surface for contacting the light-receiving surface metal electrode, and the surface of the boron diffusion layer is a pyramid-shaped surface because the boron diffusion layer is obtained by boron diffusion on the N-type silicon substrate. In the gold-semiconductor contact structure formed by the mutual contact of the boron diffusion layer and the light-receiving surface metal electrode, the contact area of the boron diffusion layer and the light-receiving surface metal electrode includes a first contact area and a second contact area outside the first contact area. The first contact area has a plurality of first conductive microstructures, and the second contact area has a plurality of second conductive microstructures.

[0126] The first conductive microstructure is located between the metal electrode and the pyramid structure, and the first conductive microstructure is arranged on the pyramid structure with a flat surface. The light-receiving surface metal electrode is a silver electrode, and the first conductive microstructure is a eutectic particle composed of silver elements and silicon elements. From the top of the pyramid structure to the bottom of the pyramid structure, the distribution density of the plurality of conductive microstructures on the pyramid structure changes in a decreasing region.

[0127] The second conductive microstructure is included in a glass phase of the metal electrode, and the second conductive microstructure is a silver single-element particle.

[0128] The gold-semiconductor contact structure is subjected to scanning electron microscope (SEM) testing, and an SEM image obtained is as shown in Figures 6 to 8 The SEM testing method of the gold-semiconductor contact structure is described as follows:

[0129] A nitric acid solution with a mass fraction of 50% to 80% is heated to 60°C to 85°C by using a chemical etching method, then the solar cell is immersed in the nitric acid solution for 3 to 10 minutes, and after the metal electrode is removed, the solar cell is photographed by using the scanning electron microscope, and an SEM image obtained is as shown in Figure 8The image shows a SEM image. The image reveals the distribution of the glass phase beneath the electrode. The area circled in the image represents the approximate distribution of the glass phase, which includes elemental silver particles.

[0130] Next, rinse the residual chemical solution with deionized or distilled water; then immerse the cleaned solar cell in a 1%–10% hydrofluoric acid solution for 2–5 minutes to remove residual glass phase material; finally, rinse the residual chemical solution with deionized or distilled water to complete the etching process. Using a scanning electron microscope at different magnifications, images are obtained as follows: Figure 6 and Figure 7 The SEM image shows the distribution of the first conductive microstructure on the surface of the doped semiconductor layer (i.e., the surface of the pyramid structure). It is understandable that the acid concentration, etching temperature, and time used in the above etching methods can be adaptively adjusted according to the removal effect, as long as the metal electrode and glass phase material can be removed. For example, increasing the acid concentration and / or raising the temperature can appropriately shorten the etching time to achieve better removal of the metal electrode and glass phase material.

[0131] Combination Figures 6 to 7 It can be seen that in the gold-semiconductor contact structure of the light-receiving surface, the pyramid structure of the boron-expanded layer (the surface of the silicon substrate before boron expansion) has the structural characteristics of high surface integrity and relatively flat surface. There is no obvious large-area corrosion or many holes at the pyramid tip, nor is there a large number of pits or pit islands on the side of the pyramid. It can be seen that the pyramid structure surface of the doped semiconductor layer in the embodiment of this application maintains a high degree of structural integrity.

[0132] The eutectic particles have a particle size of 10 nm to 200 nm; the number of eutectic particles is 100 to 1500 within any 10 μm × 10 μm region of the first contact area. The first conductive microstructures are spaced apart and dispersed on the pyramid structure, mainly in a conical distribution near the pyramid apex. The side length of the base of the pyramid structure ranges from 0.35 μm to 2.5 μm; the diagonal of the base of the pyramid structure ranges from 0.5 μm to 3.5 μm.

[0133] Example 2

[0134] This embodiment provides a solar cell. The main difference between this embodiment and Embodiment 1 is the distribution of the first conductive microstructure on the pyramid structure.

[0135] The pyramid structure includes a plurality of first pyramid structures and a plurality of second pyramid structures distributed between the first pyramid structures; the base of the first pyramid structure has a diagonal range of 1.5 μm to 3.5 μm, and the base of the second pyramid structure has a diagonal range of 0.5 μm to 1.5 μm.

[0136] The first conductive microstructure has a first distribution area and a second distribution area on the surface of the first pyramid structure; in the first distribution area, the distribution density of the first conductive microstructure is 100 / μm 2 ~ 400 / μm 2 In the second distribution area, the distribution density of the first conductive microstructure is 20 / μm 2 ~ 100 / μm 2 , and the distribution of the first conductive microstructure in the first distribution area is denser than that in the second distribution area; wherein the slope length of the pyramid structure is L, the area with a radius less than or equal to R centered on the tip of the pyramid structure is the first distribution area, and the surface of the pyramid structure outside the first distribution area is the second distribution area, R / L = 2:3.

[0137] The distribution density of the first conductive microstructure on the surface of the second pyramid structure is 30 / μm 2 ~ 100 / μm 2 . Referring to Figure 9 , which is an SEM image of the first conductive microstructure distributed on the doped semiconductor layer in the gold-semiconductor contact structure of the embodiment, and the distribution of the first conductive microstructure on the pyramid structure.

[0138] Performance test description:

[0139] Open-circuit voltage, fill factor, and photoelectric conversion efficiency test:

[0140] The open-circuit voltage, fill factor, and photoelectric conversion efficiency are tested using a halm test sorting device. The halm machine is a device that simulates sunlight, and is equipped with an electronic load, data acquisition and calculation equipment, etc., which is used to test the electrical performance of photovoltaic devices (including solar cells). The silicon wafer of the solar cell controlled in the test is 210 size, and the calibrated light intensity is 1000±5 W / m 2 .

[0141] Contact resistance test: the contact resistance performance test is performed using a contact resistance tester (such as TLM-STD of American Energy Photovoltaic). The characteristic impedance of the transmission line is determined by measuring the current and voltage, and then the value of the contact resistance is derived according to the characteristic impedance by a calculation formula. The width of the test sample is 6 mm.

[0142] Table 1: Performance test results of each embodiment

[0143]

[0144] As can be seen from the test results in Table 1, the normalized series resistance of the solar cells in Embodiment 1 and Embodiment 2 of the present application is 0.01 Ω·cm 2 ~ 0.02 Ω·cm 2 and around, the photoelectric conversion efficiency reaches 26.35% or above, which is obviously higher than the photoelectric conversion efficiency of less than 25% of the same type of solar cells. It can be seen that the solar cells in Embodiments 1 and 2 of the present application both have excellent series resistance performance and high photoelectric conversion efficiency. In particular, the open circuit voltage, fill factor and series resistance performance of Embodiment 2 are all better than those of Embodiment 1, indicating that the cooperation of the first type of pyramid structure and the second type of pyramid structure and the distribution of the first conductive microstructure on the above pyramid structure help to further improve the photoelectric conversion efficiency of the solar cell.

[0145] The above has introduced the technical solutions disclosed in the embodiments of the present application in detail, and the principles and implementation modes of the present application have been described by applying specific examples. The above description of the embodiments is only for helping to understand the technical solutions and core invention points of the embodiments of the present application. Meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation modes and application ranges will all have changes. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A gold-semiconductor contact structure, characterized in that, The gold-semiconductor contact structure includes: A doped semiconductor layer, wherein the surface of the doped semiconductor layer has a pyramidal structure. The metal electrode is in contact with the doped semiconductor layer; The contact area between the doped semiconductor layer and the metal electrode includes a first contact area, and the first contact area has a plurality of first conductive microstructures. The first conductive microstructure is located between the metal electrode and the pyramid structure, and is disposed on the flat surface of the pyramid structure. The particles of the first conductive microstructure are eutectic particles composed of metal elements and semiconductor elements. The metal elements are the same as those in the metal electrode, and the semiconductor elements are the same as those in the doped semiconductor layer. Specifically, from the apex of the pyramid structure to the base of the pyramid structure, the distribution density of the first conductive microstructure on the pyramid structure shows a decreasing trend.

2. The gold-semiconductor contact structure according to claim 1, characterized in that, The eutectic particles have a particle size of 10 nm to 200 nm; and / or, Within any 10μm × 10μm region of the first contact area, the number of eutectic particles is 100 to 1500; and / or, A plurality of the first conductive microstructures are spaced apart and dispersedly distributed on the surface of the pyramid structure; and / or, At least a portion of the first conductive microstructures are distributed in a conical shape on the pyramid structure.

3. The gold-semiconductor contact structure according to claim 1, characterized in that, The side length of the base of the pyramid structure ranges from 0.35 μm to 2.5 μm; and / or, The diagonal range of the base of the pyramid structure is 0.5μm to 3.5μm.

4. The gold-semiconductor contact structure according to claim 3, characterized in that, The pyramid structure includes: a plurality of first-type pyramid structures and a plurality of second-type pyramid structures distributed among the first-type pyramid structures; The diagonal range of the base of the first type of pyramid structure is 1.5μm to 3.5μm, and the diagonal range of the base of the second type of pyramid structure is 0.5μm to 1.5μm.

5. The gold-semiconductor contact structure according to claim 4, characterized in that, The first conductive microstructure has a first distribution region and a second distribution region on the surface of the first type of pyramid structure. In the first distribution region, the distribution density of the first conductive microstructure is 100 per μm. 2 ~400 cells / μm 2 In the second distribution region, the distribution density of the first conductive microstructure is 20 per μm. 2 ~100 particles / μm 2 Furthermore, the first conductive microstructure is more densely distributed in the first distribution area than in the second distribution area; wherein, the slope side length of the pyramid structure is L, the area with a radius less than or equal to R centered on the pyramid apex is the first distribution area, the surface of the pyramid structure outside the first distribution area is the second distribution area, and R / L≤2:3; The distribution density of the first conductive microstructure on the surface of the second type of pyramid structure is 30 microstructures / μm. 2 ~100 particles / μm 2 .

6. The gold-semiconductor contact structure according to claim 1, characterized in that, The contact area between the doped semiconductor layer and the metal electrode further includes a second contact area, which is located outside the first contact area and has a plurality of second conductive microstructures. The second conductive microstructure is encapsulated in the glass phase of the metal electrode. The second conductive microstructure is a metal element particle, and the metal element particle is the same as the metal element in the metal electrode.

7. The gold-semiconductor contact structure according to claim 6, characterized in that, Within the preset area of ​​the contact area, the area ratio of the second contact area to the preset area is 1:5 to 1:3; wherein, the preset area is an area with any preset width × preset length centered on the centerline of the width of the metal electrode, the preset width is perpendicular to the width of the metal electrode and is less than or equal to 23μm, and the preset length is parallel to the width of the metal electrode and is less than or equal to 16μm.

8. The gold-semiconductor contact structure according to any one of claims 1 to 7, characterized in that, The doped semiconductor layer includes at least one of a doped amorphous silicon layer, a doped polycrystalline silicon layer, a doped microcrystalline silicon layer, or a doped crystalline silicon layer; and / or, The doping element in the doped semiconductor layer includes at least one of N-type or P-type conductive elements; and / or The metallic element includes at least one of silver, lead, copper, aluminum, nickel, cadmium, or bismuth.

9. A solar cell, characterized in that, The solar cell includes a silicon substrate and a gold semi-contact structure located on the silicon substrate, the gold semi-contact structure comprising: A doped semiconductor layer is disposed on the surface of the silicon substrate, and the surface of the doped semiconductor layer facing away from the silicon substrate has a pyramidal structure. A metal electrode is located on the side of the doped semiconductor layer away from the silicon substrate, and the metal electrode is in contact with the doped semiconductor layer. The contact area between the doped semiconductor layer and the metal electrode includes a first contact area, and the first contact area has a plurality of first conductive microstructures. The first conductive microstructure is located between the metal electrode and the pyramid structure, and is disposed on the flat surface of the pyramid structure. The particles of the first conductive microstructure are eutectic particles composed of metal elements and semiconductor elements. The metal elements are the same as those in the metal electrode, and the semiconductor elements are the same as those in the doped semiconductor layer. Specifically, from the apex of the pyramid structure to the base of the pyramid structure, the distribution density of the first conductive microstructure on the pyramid structure shows a decreasing trend.

10. The solar cell according to claim 9, characterized in that, The solar cell includes: On the light-receiving surface of the silicon substrate, a first doped semiconductor layer, a first passivation layer, and a first metal electrode are sequentially disposed in a direction away from the light-receiving surface. The first doped semiconductor layer has a conductivity type opposite to that of the silicon substrate. The first metal electrode passes through the first passivation layer and contacts the first doped semiconductor layer, so that the first doped semiconductor layer and the first metal electrode form the gold-semiconductor contact structure. On the backlight surface of the silicon substrate, a passivation contact structure, a second passivation layer, and a second metal electrode are sequentially provided in a direction away from the backlight surface. The passivation contact structure includes a dielectric layer disposed close to the silicon substrate and a second doped semiconductor layer disposed away from the silicon substrate. The second doped semiconductor layer has the same conductivity type as the silicon substrate. The second metal electrode passes through the second passivation layer and makes an ohmic contact with the second doped semiconductor layer.

11. The solar cell according to claim 10, characterized in that, The first doped semiconductor layer is formed by thermal diffusion of dopant elements into the silicon substrate, or the first doped semiconductor layer is a doped polycrystalline silicon layer or a doped amorphous silicon layer deposited on the light-receiving surface of the silicon substrate; and / or, The first passivation layer is one or more layers of aluminum oxide, silicon oxide, silicon oxynitride, or silicon nitride deposited on the PN junction region; and / or, The dielectric layer is at least one of a silicon oxide layer, an amorphous silicon layer, a polycrystalline silicon layer, and a silicon carbide layer; and / or, The second passivation layer is one or more layers of silicon oxide, silicon oxynitride, or silicon nitride deposited on the second doped semiconductor layer.

12. A photovoltaic module, characterized in that, The photovoltaic module includes a solar cell as described in any one of claims 9 to 11, wherein a plurality of the solar cells are connected in series and / or in parallel to form a solar cell string; The solar cell string is encapsulated within the encapsulation structure.

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