Solar cell, method for preparing same, and photovoltaic module

Abstract

The present invention relates to the technical field of solar cells, and discloses a solar cell, a preparation method thereof, and a photovoltaic module. The solar cell includes: a silicon substrate, the silicon substrate includes a light-receiving surface and a backlight surface arranged opposite to each other; a first passivation layer, the first passivation layer is disposed on the light-receiving surface of the silicon substrate; a patterned first doped silicon layer, the first doped silicon layer is located on a part of the first passivation layer; a patterned dielectric layer, the dielectric layer is located on the remaining part of the first passivation layer not covered with the first doped silicon layer; a first transparent conductive layer, the first transparent conductive layer is located on the first doped silicon layer and the dielectric layer. Under the synergistic effect of the patterned dielectric layer and the patterned first doped silicon layer, the parasitic absorption of light by the first doped silicon layer can be effectively reduced, the recombination of carriers can be reduced, the short-circuit current of the solar cell can be increased, and the photoelectric conversion efficiency of the solar cell can be optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and particularly to a solar cell, a preparation method thereof, and a photovoltaic module. Background Art

[0002] The utilization rate of sunlight by a solar cell is a key factor affecting the performance of the solar cell. Taking a heterojunction solar cell as an example, a doped silicon layer is provided on the light-receiving surface of the heterojunction solar cell. This doped silicon layer has a light-absorbing property, which will affect the light absorption of the solar cell, resulting in a relatively high parasitic absorption of light by the solar cell. This will lead to a reduction in the utilization rate of sunlight, making it difficult to more effectively improve the photoelectric conversion performance of the solar cell. Summary of the Invention

[0003] Embodiments of the present invention disclose a solar cell, a preparation method thereof, and a photovoltaic module. This solar cell can effectively reduce the parasitic absorption of light by the doped silicon layer, reduce the recombination of carriers, increase the short-circuit current of the solar cell, and optimize the photoelectric conversion efficiency of the solar cell.

[0004] In a first aspect, embodiments of the present application disclose a solar cell, which includes:

[0005] A silicon substrate, which includes a light-receiving surface and a backlight surface arranged opposite to each other;

[0006] A first passivation layer, which is disposed on the light-receiving surface of the silicon substrate;

[0007] A patterned first doped silicon layer, which is located on a part of the first passivation layer;

[0008] A patterned dielectric layer, which is located on the remaining part of the first passivation layer that is not covered with the first doped silicon layer;

[0009] A first transparent conductive layer, which is located on the first doped silicon layer and the dielectric layer.

[0010] Further, the thickness of the first doped silicon layer is greater than the thickness of the dielectric layer.

[0011] Further, the thickness of the dielectric layer is 1 nm to 2 nm; and / or,

[0012] The thickness of the first doped silicon layer is 10 nm to 30 nm.

[0013] Further, the first transparent conductive layer located on the dielectric layer and the first transparent conductive layer located on the first doped silicon layer present a stepped structure.

[0014] Furthermore, the refractive indices of the first passivation layer, the dielectric layer, and the first transparent conductive layer show a decreasing trend.

[0015] Furthermore, the refractive index of the first passivation layer is 3.5 - 4.0; and / or,

[0016] the refractive index of the dielectric layer is 1.8 - 2.2; and / or,

[0017] the refractive index of the first transparent conductive layer is 1.7 - 2.1.

[0018] Furthermore, the material of the dielectric layer includes at least one of silicon oxide, silicon nitride, and silicon oxynitride; and / or,

[0019] the doping concentration of the first doped silicon layer is 1×10 20 atoms / cm 3 ~5×10 21 atoms / cm 3 ; and / or,

[0020] Along the first direction, the width of the first doped silicon layer is 30 μm - 50 μm, and the first direction is perpendicular to the thickness direction of the solar cell.

[0021] Furthermore, along the second direction, the first doped silicon layer sequentially includes: a first doped sub - layer, a second doped sub - layer, a third doped sub - layer, and an oxygen - free contact layer, and the second direction is the direction from the silicon substrate to the first transparent conductive layer;

[0022] wherein, the thickness of the first doped sub - layer is 0.2 nm - 1 nm; and / or,

[0023] the thickness of the second doped sub - layer is 3 nm - 6 nm; and / or,

[0024] the thickness of the third doped sub - layer is 10 nm - 15 nm; and / or,

[0025] the thickness of the oxygen - free contact layer is 2 nm - 5 nm.

[0026] Furthermore, the solar cell further includes a first electrode, and the first electrode is disposed on the surface of the first transparent conductive layer facing away from the silicon substrate;

[0027] In the planar direction of the solar cell, the orthographic projection pattern of the first electrode is located within the orthographic projection pattern of the first doped silicon layer.

[0028] Further, along the second direction, the first passivation layer includes a first passivation sublayer, a second passivation sublayer, a third passivation sublayer and a fourth passivation sublayer in sequence, wherein the first passivation sublayer and the second passivation sublayer are non-hydrogenated passivation layers, and the third passivation sublayer and the fourth passivation sublayer are hydrogenated passivation layers; the second direction is the direction from the silicon substrate to the first transparent conductive layer.

[0029] Furthermore, the backlight surface of the silicon substrate is provided with a second passivation layer, and a second doped silicon layer, a second transparent conductive layer and a second electrode are sequentially provided on a surface of the second passivation layer facing away from the silicon substrate.

[0030] In a second aspect, the present application discloses a method for preparing a solar cell, the method comprising the following steps:

[0031] Preparing a first passivation layer on the light-receiving surface of the silicon substrate;

[0032] forming a patterned first doped silicon layer on a portion of the first passivation layer;

[0033] preparing a patterned dielectric layer on the remaining portion of the first passivation layer not covered by the first doped silicon layer;

[0034] A first transparent conductive layer is prepared on the dielectric layer and the first doped silicon layer.

[0035] Furthermore, the step of preparing a patterned first doped silicon layer on a portion of the first passivation layer comprises:

[0036] preparing a first doped sublayer on a portion of the first passivation layer;

[0037] preparing a second doped sublayer on the first doped sublayer;

[0038] preparing a third doped sublayer on the second doped sublayer;

[0039] An oxygen-free contact layer is prepared on the third doped sublayer.

[0040] Further, in the step of preparing the first doped sublayer, the preparation parameters include: the process gas includes SiH4, N2O and H2, and the flow ratio of SiH4, N2O and H2 is 1:1:250~1:8:350, the gas pressure is 4 Torr~6 Torr, the ignition power is 6000 W~8000 W, and the ignition time is 4 s~10 s; and / or,

[0041] In the step of preparing the second doped sub-layer, the preparation parameters include: the process gas includes SiH4, N2O, the first doping gas source and H2, and the flow rate ratio of SiH4, N2O, the first doping gas source and H2 is 1:0.5:5:200 to 1:2:10:250, the gas pressure is 4 Torr to 6 Torr, the glow power is 8000 W to 12000 W, and the glow time is 30 s to 60 s; and / or,

[0042] In the step of preparing the third doped sub-layer, the preparation parameters include: the process gas includes SiH4, N2O, the first doping gas source and H2, and the flow rate ratio of SiH4, N2O, the first doping gas source and H2 is 1:0.5:7:180 to 1:2:15:220, the gas pressure is 4 Torr to 6 Torr, the glow power is 8000 W to 12000 W, and the glow time is 100 s to 150 s; and / or,

[0043] In the step of preparing the oxygen-free contact layer, the preparation parameters include: the process gas includes SiH4, the first doping gas source and H2, and the flow rate ratio of SiH4, the first doping gas source and H2 is 1:10:180 to 1:15:220, the gas pressure is 4 Torr to 6 Torr, the glow power is 8000 W to 12000 W, and the glow time is 20 s to 50 s.

[0044] Further, in the step of preparing the patterned dielectric layer on the remaining portion of the first passivation layer not covered by the first doped silicon layer, the preparation parameters include: the process gas includes SiH4, the oxygen-containing gas and H2, and the flow rate ratio of SiH4, the oxygen-containing gas and H2 is 1:1:10 to 1:4:100, the gas pressure is 0.4 Torr to 0.7 Torr, the glow power is 500 W to 1500 W, and the glow time is 5 s to 20 s.

[0045] Further, before the step of preparing the patterned first doped silicon layer on a part of the first passivation layer and after the step of preparing the first passivation layer on the light-receiving surface of the silicon substrate, the method for manufacturing the solar cell further includes: preparing the second passivation layer on the backlight surface of the silicon substrate; and / or,

[0046] A second passivation layer is provided on the backlight surface of the silicon substrate. Before the step of preparing the patterned dielectric layer on the remaining portion of the first passivation layer not covered by the first doped silicon layer, the method for manufacturing the solar cell further includes: preparing the second doped silicon layer on the second passivation layer; and / or,

[0047] After the step of forming the first transparent conductive layer on the dielectric layer and the first doped silicon layer, the method for manufacturing the solar cell further includes:

[0048] Forming a second transparent conductive layer on the second doped silicon layer;

[0049] Forming a first electrode on the first transparent conductive layer;

[0050] Forming a second electrode on the second transparent conductive layer.

[0051] In a third aspect, an embodiment of the present application discloses a photovoltaic module, which includes: the solar cell according to any one of the first aspect, or the solar cell manufactured by the manufacturing method according to any one of the second aspect.

[0052] Compared with the prior art, the beneficial effects of the present application are as follows:

[0053] The present application provides a solar cell, a manufacturing method thereof, and a photovoltaic module. Among them, a light-receiving surface of a silicon substrate is sequentially provided with a first passivation layer, a patterned first doped silicon layer, a patterned dielectric layer, and a first transparent conductive layer. Among them, under the synergistic effect of the patterned dielectric layer and the patterned first doped silicon layer, the parasitic absorption of light by the first doped silicon layer can be effectively reduced, the recombination of carriers can be reduced, the short-circuit current of the solar cell can be increased, and the photoelectric conversion efficiency of the solar cell can be optimized.

[0054] Specifically, a patterned first doped silicon layer and a patterned dielectric layer are disposed on the first passivation layer. Therefore, due to the different energy bands of the dielectric layer and the first doped silicon layer, charge accumulation will occur at their interface, increasing the intensity of the lateral electric field, reducing the recombination of carriers at the interface, and improving the lateral transport ability of carriers. And, since the coverage area of the patterned first doped silicon layer on the silicon substrate is small, the parasitic absorption of sunlight by the first doped silicon layer can be effectively reduced, and the short-circuit current of the solar cell can be increased.

[0055] In addition, since the dielectric layer is located between the first passivation layer and the first transparent conductive layer, the dielectric layer can improve the work function mismatch problem between the first passivation layer and the first transparent conductive layer, thereby helping to reduce the transport barrier of carriers and reducing the recombination of carriers at the interface; and, the dielectric layer can also effectively prevent the first transparent conductive layer from damaging the first passivation layer, thereby ensuring the passivation effect of the first passivation layer to a high degree. In addition, the dielectric layer can also passivate the defects of the first passivation layer, thereby reducing the recombination of carriers to a high degree and improving the performance of the solar cell. Description of the Drawings

[0056] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0057] Figure 1 is a schematic structural diagram of a solar cell provided by an embodiment of the present application;

[0058] Figure 2 is a schematic structural diagram of a first doped silicon layer and a dielectric layer provided by an embodiment of the present application;

[0059] Figure 3 is another schematic structural diagram of a first doped silicon layer and a dielectric layer provided by an embodiment of the present application;

[0060] Figure 4 is a schematic structural diagram of the light-receiving surface of a silicon substrate (the first electrode is not shown) provided by an embodiment of the present application;

[0061] Figure 5 is a schematic structural diagram of a solar cell containing an enlarged view of a first doped silicon layer provided by an embodiment of the present application;

[0062] Figure 6 is a schematic structural diagram of a solar cell containing an enlarged view of a first passivation layer provided by an embodiment of the present application;

[0063] Figure 7 is a schematic structural diagram of a solar cell containing an enlarged view of a second passivation layer provided by an embodiment of the present application;

[0064] Figure 8 is a schematic structural diagram of a solar cell containing an enlarged view of a second doped silicon layer provided by an embodiment of the present application.

[0065] Reference numerals: 1, silicon substrate; 1a, light-receiving surface; 1b, backlight surface; 2, first passivation layer; 21, first passivation sub-layer; 22, second passivation sub-layer; 23, third passivation sub-layer; 24, fourth passivation sub-layer; 3, first doped silicon layer; 31, first doping sub-layer; 32, second doping sub-layer; 33, third doping sub-layer; 34, oxygen-free contact layer; 4, dielectric layer; 5, first transparent conductive layer; 6, first electrode; 7, second passivation layer; 71, fifth passivation sub-layer; 72, sixth passivation sub-layer; 73, seventh passivation sub-layer; 74, eighth passivation sub-layer; 8, second doped silicon layer; 81, fourth doping sub-layer; 82, fifth doping sub-layer; 83, sixth doping sub-layer; 84, seventh doping sub-layer; 9, second transparent conductive layer; 10, second electrode. Detailed implementation manners

[0066] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0067] In the present invention, the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit that the indicated devices, elements or components must have a specific orientation, or be constructed and operated in a specific orientation.

[0068] Moreover, in addition to being able to represent the orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0069] In addition, terms such as "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, the meaning of "a plurality" is two or more.

[0070] Next, the technical solutions provided by the present invention will be further described in conjunction with the embodiments and the accompanying drawings.

[0071] The utilization rate of sunlight by a solar cell is a key factor affecting the performance of the solar cell. Taking a heterojunction solar cell as an example, a doped silicon layer is provided on the light-receiving surface of the heterojunction solar cell. However, the existence of the doped silicon layer will cause serious parasitic absorption, which will lead to a reduction in the utilization rate of sunlight and an increase in the recombination of carriers, making it difficult to more effectively improve the optoelectronic conversion performance of the solar cell.

[0072] This is because, on the one hand, due to the existence of doping elements in the doped silicon layer, these doping elements will generate impurity energy levels, enabling carriers to transition to the impurity energy levels during transition, thereby generating parasitic absorption; on the other hand, due to the difference in the crystal lattice between the doping elements and silicon atoms, it will cause partial distortion of the silicon lattice, thereby generating parasitic absorption.

[0073] Based on the above problems, an embodiment of the present application discloses a solar cell, which can effectively reduce the parasitic absorption of light by the doped silicon layer, reduce the recombination of carriers, and improve the photoelectric conversion efficiency of the solar cell.

[0074] In the first aspect, as Figure 1 shown, an embodiment of the present application discloses a solar cell, which includes:

[0075] A silicon substrate 1, the silicon substrate 1 includes a light-receiving surface 1a and a backlight surface 1b arranged opposite to each other;

[0076] A first passivation layer 2, the first passivation layer 2 is disposed on the light-receiving surface 1a of the silicon substrate 1;

[0077] A patterned first doped silicon layer 3, the first doped silicon layer 3 is located on a part of the first passivation layer 2;

[0078] A patterned dielectric layer 4, the dielectric layer 4 is located on the remaining part of the first passivation layer 2 that is not covered with the first doped silicon layer 3;

[0079] A first transparent conductive layer 5, the first transparent conductive layer 5 is located on the first doped silicon layer 3 and the dielectric layer 4.

[0080] Wherein, the patterned first doped silicon layer 3 means that only a part of the area on the first passivation layer 2 is provided with the first doped silicon layer 3; the patterned dielectric layer 4 means that only a part of the area on the first passivation layer 2 is provided with the dielectric layer 4.

[0081] In the present application, by providing a patterned first doped silicon layer 3 and a patterned dielectric layer 4 on the first passivation layer 2, and utilizing the synergistic effect of the two, the parasitic absorption of the first doped silicon layer 3 is reduced to a high degree, the recombination of carriers is reduced, the short-circuit current of the solar cell is increased, and the photoelectric conversion efficiency of the solar cell is optimized.

[0082] In this application, by fabricating a patterned first doped silicon layer 3 on the first passivation layer 2, it helps to reduce the parasitic absorption of the first doped silicon layer 3, improve the utilization rate of sunlight, and increase the short-circuit current. However, the applicant found that reducing the area of the first doped silicon layer 3 on the first passivation layer 2 helps to reduce the parasitic absorption on the light-receiving surface. However, the patterned first doped silicon layer 3 results in an increase in the boundaries of the first doped silicon layer 3, and the increase in boundaries may generate more defects and increase the recombination of carriers at the boundaries. Moreover, the patterned first doped silicon layer 3 also causes part of the first passivation layer 2 to be in direct contact with the first transparent conductive layer 5, deteriorating the contact performance between the first transparent conductive layer 5 and the first passivation layer 2. In addition, when the first transparent conductive layer 5 is directly disposed on the first passivation layer 2, the structure of the first passivation layer 2 will also be damaged during the preparation of the first transparent conductive layer 5. Therefore, in this application, by further providing a patterned dielectric layer 4, it helps to reduce the recombination of carriers and improve the performance of the solar cell.

[0083] Among them, by respectively providing a patterned first doped silicon layer 3 and a dielectric layer 4 on the first passivation layer 2, and due to the different energy bands of the first passivation layer 2 and the first doped silicon layer 3, there is charge accumulation at their interface, increasing the intensity of the lateral electric field, reducing the recombination of carriers at the interface, and highly improving the lateral transport ability of carriers.

[0084] In addition, since the dielectric layer 4 is located between the first passivation layer 2 and the first transparent conductive layer 5, it can improve the problem of work function mismatch between the first passivation layer 2 and the first transparent conductive layer 5, help reduce the transport barrier of carriers, and reduce the recombination of carriers at the interface. Moreover, the dielectric layer 4 can also effectively prevent the first transparent conductive layer 5 from damaging the first passivation layer 2, thus highly ensuring the passivation effect of the first passivation layer 2. In addition, the dielectric layer 4 can also passivate the defects on the first passivation layer 2, thereby highly reducing the recombination of carriers and improving the performance of the solar cell.

[0085] In addition, for the first doped silicon layer 3 of this application, the first doped silicon layer 3 of this application is one of an N-type semiconductor layer or a P-type semiconductor layer, which is achieved by adding a doping element to the silicon material to change the electrical properties of the silicon material. The silicon material modified by the doping element includes at least one of a doped microcrystalline silicon layer, a doped polycrystalline silicon layer, and a doped amorphous silicon layer, and the above materials all have the property of light absorption. Therefore, in order to reduce the parasitic absorption of the first doped silicon layer 3, this application reduces the coverage area of the first doped silicon layer 3 on the first passivation layer 2 by providing a patterned first doped silicon layer 3, reducing the parasitic absorption.

[0086] However, the patterned first doped silicon layer 3 also causes part of the first passivation layer 2 to be in direct contact with the first transparent conductive layer 5, which will lead to poor contact performance between the first transparent conductive layer 5 and the first passivation layer 2; and the structure of the first passivation layer 2 will also be damaged during the preparation of the first transparent conductive layer 5. Therefore, in order to avoid additional parasitic absorption and further improve the contact performance and protect the first passivation layer 2, a dielectric layer 4 is provided between the first passivation layer 2 and the first transparent conductive layer 5 in this application.

[0087] Therefore, for the dielectric layer 4, in order to avoid parasitic absorption and improve the contact performance and protect the film structure of the first passivation layer 2, the material of the dielectric layer 4 should be different from that of the first doped silicon layer 3, so that there is a difference in the energy bands between the dielectric layer 4 and the first doped silicon layer 3.

[0088] Specifically, the material of the dielectric layer 4 includes at least one of silicon oxide, silicon nitride, and silicon oxynitride. Selecting the above materials as the dielectric layer 4, the dielectric layer 4 has the effect of protecting the first passivation layer 2; in addition, when selecting the above materials as the dielectric layer 4, the dielectric layer 4 has a high antireflection effect, which can further improve the light utilization rate and the performance of the solar cell. Preferably, when hydrogenated silicon oxide is selected, its passivation performance is higher, which helps to reduce the recombination of carriers; and the light transmittance performance is higher, which is more conducive to improving the light utilization rate.

[0089] Among them, the doped silicon layer includes at least one of a doped microcrystalline silicon layer, a doped polycrystalline silicon layer, and a doped amorphous silicon layer.

[0090] In addition, the passivation layer includes an intrinsic amorphous silicon layer; the transparent conductive layer is at least one of an indium tin oxide layer, an indium zinc oxide layer, an indium tungsten oxide layer, and an indium cerium oxide layer.

[0091] In an alternative embodiment, as Figure 2 shown, the thickness of the first doped silicon layer 3 is the same as that of the dielectric layer 4, that is, the surface of the first doped silicon layer 3 facing away from the first passivation layer 2 is flush with the surface of the dielectric layer 4 facing away from the first passivation layer 2. In another alternative embodiment, as Figure 3 shown, the thickness of the first doped silicon layer 3 is greater than that of the dielectric layer 4, that is, the surface of the first doped silicon layer 3 facing away from the first passivation layer 2 is higher than the surface of the dielectric layer 4 facing away from the first passivation layer 2, so as to form a stepped structure between the two. In this embodiment, on the one hand, since the thickness of the dielectric layer 4 is small, it helps the transport of carriers; on the other hand, the stepped structure makes part of the side surface of the first doped silicon layer 3 higher than the surface of the dielectric layer 4, and this exposed side surface is in direct contact with the first transparent conductive layer 5, increasing the contact area between the first doped silicon layer 3 and the first transparent conductive layer 5, which helps to provide more carrier transport channels.

[0092] Among them, the thickness of the dielectric layer 4 is 1 nm to 2 nm. When the dielectric layer 4 is at this thickness, it helps the tunneling of carriers and further shortens the propagation distance of light. Exemplarily, the thickness of the dielectric layer 4 is 1 nm, 1.2 nm, 1.5 nm, 1.8 nm, 2 nm, etc.

[0093] The thickness of the first doped silicon layer 3 is 10 nm to 30 nm. When the first doped silicon layer 3 is at the above thickness, it further helps the carrier transport ability and can avoid generating more parasitic absorption of light. The thickness of the first doped silicon layer 3 is 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, etc.

[0094] In addition, the thickness refers to the average thickness. Taking the thickness of the doped silicon layer as an example, it is a value obtained by calculating the thickness values measured at multiple positions of the doped silicon layer, which reflects the overall thickness level of the doped silicon layer in the thickness direction.

[0095] Furthermore, an ellipsometer is used to measure the thickness of the doped silicon layer. At least five points are taken on the doped silicon layer, and the thickness values of these five points are measured respectively, and then the average value of the measurement data is obtained. For example, an ellipsometer with the manufacturer being Sentch of Germany and the model being SE-800 can be used for the film thickness measurement. The present application does not limit the specific measurement method here, as long as the purpose of the present application can be achieved.

[0096] Furthermore, as Figure 4 shown, the first transparent conductive layer 5 located on the dielectric layer 4 and the first transparent conductive layer 5 located on the first doped silicon layer 3 present a stepped structure.

[0097] In an alternative embodiment, the formation of the stepped structure of the first transparent conductive layer 5 is affected by the structure of the first doped silicon layer 3. Among them, since the thickness of the first doped silicon layer 3 is greater than the thickness of the dielectric layer 4, the first doped silicon layer 3 and the dielectric layer 4 form a stepped structure. Therefore, when the first transparent conductive layer 5 is deposited on this stepped structure, it presents a stepped structure.

[0098] Furthermore, the refractive indices of the first passivation layer 2, the dielectric layer 4, and the first transparent conductive layer 5 show a decreasing trend. Due to the decreasing trend of the refractive index, the light utilization rate of the solar cell is improved.

[0099] In addition, the refractive index of the first passivation layer 2 is 3.5 to 4.0; the refractive index of the dielectric layer 4 is 1.8 to 2.2; the refractive index of the first transparent conductive layer 5 is 1.7 to 2.1. When the refractive indices of the first passivation layer 2, the dielectric layer 4, and the first transparent conductive layer 5 are within the above ranges, the matching degree between the layers is higher, which helps to further improve the utilization rate of sunlight.

[0100] Further, the doping concentration of the first doped silicon layer 3 is 1×10 20 atoms / cm 3 ~5×10 21 atoms / cm 3 .

[0101] When the doping concentration of the first doped silicon layer 3 is within the above range, the surface field passivation effect is relatively strong, so that the interface between the first passivation layer 2 and the first doped silicon layer 3 has a relatively high electric field effect, improving the carrier transport performance. Exemplarily, the doping concentration of the first doped silicon layer 3 is 1×10 20 atoms / cm 3 , 5×10 20 atoms / cm 3 , 1×10 21 atoms / cm 3 , 5×10 21 atoms / cm 3 etc.

[0102] The doping concentration represents the content of the doping element added to the doped silicon layer, referring to the total doping concentration in the doped silicon layer. Among them, the doping element refers to the element added to the doped silicon layer to change the conduction type of the doped silicon layer. For a solar cell, the conduction type of the doped silicon layer includes N-type or P-type. For example, the doping elements with N-type characteristics include: P, As, Sb, etc., and the doping elements with P-type characteristics include: B, Al, Ga, etc.

[0103] In addition, when the doped silicon layer is a structure of multiple sub-layers stacked, the doping concentration refers to the sum of the doping concentrations of the multiple sub-layers.

[0104] In addition, the doping concentration of the doped silicon layer can be tested by using Secondary Ion Mass Spectrometry (SIMS). The present application does not limit the specific testing method here, as long as the purpose of the present application can be achieved.

[0105] In an alternative embodiment, as Figure 5 shown, along the second direction (see the Y1 direction in Figure 5 ), the first doped silicon layer 3 sequentially includes: a first doped sub-layer 31, a second doped sub-layer 32, a third doped sub-layer 33, and an oxygen-free contact layer 34. The second direction is the direction from the silicon substrate 1 to the first transparent conductive layer 5; among them, the thickness of the first doped sub-layer 31 is 0.2 nm to 1 nm; the thickness of the second doped sub-layer 32 is 3 nm to 6 nm; the thickness of the third doped sub-layer 33 is 10 nm to 15 nm; the thickness of the oxygen-free contact layer 34 is 2 nm to 5 nm.

[0106] In the above-mentioned composite layer structure, the first doped sublayer 31 acts as a seed layer to promote the growth of the second doped sublayer 32, and the presence of the second doped sublayer 32 also helps to promote the acquisition of a high-quality third doped sublayer 33. In addition, by controlling the thickness of the first doped sublayer 31, the second doped sublayer 32 and the third doped sublayer 33, the first doped sublayer 31, the second doped sublayer 32 and the third doped sublayer 33 are highly matched, have a higher stress buffering capacity, and have a higher uniformity of electric field distribution, which helps to improve the stability and photoelectric conversion performance of the solar cell. In addition, since the oxygen-free contact layer 34 has a high contact performance with the first transparent conductive layer 5, it promotes the transmission of carriers from the oxygen-free contact layer 34 to the first transparent conductive layer 5, reduces the loss of carriers at the interface, and thus improves the transmission effect of carriers.

[0107] Further, along the first direction (see Figure 1 In the X direction in FIG. 1 ), the width of the first doped silicon layer 3 is 30 μm to 50 μm, and the first direction is perpendicular to the thickness direction of the solar cell. When the width of the first doped silicon layer 3 is within the above range, on the one hand, it helps to avoid the width of the first doped silicon layer 3 being too narrow, which limits the carrier transmission capacity; on the other hand, it helps to avoid the width of the first doped silicon layer 3 being too wide, which makes it difficult to effectively improve parasitic absorption and improve the utilization rate of sunlight.

[0108] For further information, see Figure 1 The solar cell further includes a first electrode 6, which is disposed on a surface of the first transparent conductive layer 5 facing away from the silicon substrate 1. In the plane direction of the solar cell, the orthographic projection pattern of the first electrode 6 is located within the orthographic projection pattern of the first doped silicon layer 3.

[0109] Since the orthographic projection pattern of the first electrode 6 is located within the orthographic projection pattern of the first doped silicon layer 3 , it helps to shorten the transmission path of carriers to the first electrode 6 .

[0110] The orthographic projection pattern of the first electrode 6 is located within the orthographic projection pattern of the first doped silicon layer 3, including two implementations. In the first implementation, the area of ​​the orthographic projection pattern of the first electrode 6 is smaller than the area of ​​the orthographic projection pattern of the first doped silicon layer 3, that is, the orthographic projection pattern of the first electrode 6 covers part of the orthographic projection pattern of the first doped silicon layer 3; in the second implementation, the area of ​​the orthographic projection shape of the first electrode 6 is equal to the area of ​​the orthographic projection pattern of the first doped silicon layer 3, that is, the orthographic projection pattern of the first electrode 6 coincides with the orthographic projection pattern of the first doped silicon layer 3.

[0111] In addition, when the first electrode 6 is disposed on the first transparent conductive layer 5 corresponding to the position of the first doped silicon layer 3, the width of the first electrode 6 is 20 μm to 30 μm at this time. At this time, since the width of the first doped silicon layer in the present application is 30 μm to 40 μm, by setting the width of the first electrode 6 to be smaller than the width of the first doped silicon layer 3, it helps to improve the processing accuracy and ensure the effectiveness of the preparation of the first electrode 6.

[0112] Further, as Figure 6 shown, along the second direction, the first passivation layer 2 sequentially includes a first passivation sub-layer 21, a second passivation sub-layer 22, a third passivation sub-layer 23, and a fourth passivation sub-layer 24. Among them, the first passivation sub-layer 21 and the second passivation sub-layer 22 are non-hydrogenated passivation layers, and the third passivation sub-layer 23 and the fourth passivation sub-layer 24 are hydrogenated passivation layers; the second direction is the direction from the silicon substrate 1 to the first transparent conductive layer 5.

[0113] Among them, the non-hydrogenated passivation layer refers to a film layer formed without additionally introducing a hydrogen source during the preparation process. For example, hydrogen gas is not introduced during the preparation process; the hydrogenated passivation layer refers to a film layer formed by additionally introducing a hydrogen source during the preparation process. For example, hydrogen gas is introduced as a reaction gas during the preparation process.

[0114] Therefore, since the first passivation sub-layer 21 and the second passivation sub-layer 22 are non-hydrogenated passivation layers and no additional hydrogen source is introduced during the preparation, the compactness of their film layers is relatively high. Therefore, the first passivation sub-layer 21 can effectively prevent epitaxial growth and has good contact with the silicon substrate 1; the second passivation sub-layer 22 can react with the unreacted groups in the first passivation sub-layer 21 to reduce the accumulation of yellow powder; the third passivation sub-layer 23 and the fourth passivation sub-layer 24 are hydrogenated passivation layers and contain more hydrogen elements. On the one hand, the hydrogen elements in the third passivation sub-layer 23 and the fourth passivation sub-layer 24 can be used to further improve the passivation effect, and on the other hand, the crystallization rate of the fourth passivation sub-layer 24 can be improved, so that it has good contact performance with the first doped silicon layer 3 and the second doped silicon layer 8, thereby making better use of the high field strength effect of the first doped silicon layer 3 and improving the carrier transport ability.

[0115] Further, the thickness of the first passivation sub-layer 21 is 0.5 nm to 3 nm; the thickness of the second passivation sub-layer 22 is 0.1 nm to 1 nm; the thickness of the third passivation sub-layer 23 is 2 nm to 6 nm; the thickness of the fourth passivation sub-layer 24 is 0.5 nm to 2 nm.

[0116] Further, referring back to Figure 1 , a second passivation layer 7 is provided on the backlight surface 1b of the silicon substrate 1, and a second doped silicon layer 8, a second transparent conductive layer 9, and a second electrode 10 are sequentially provided on the surface of the second passivation layer 7 facing away from the silicon substrate 1.

[0117] Further, as Figure 7 shown, along the second direction (see the Y2 direction in Figure 7 ), the second passivation layer 7 successively includes a fifth passivation sub-layer 71, a sixth passivation sub-layer 72, a seventh passivation sub-layer 73, and an eighth passivation sub-layer 74. Among them, the fifth passivation sub-layer 71 and the sixth passivation sub-layer 72 are non-hydrogenated passivation layers, and the seventh passivation sub-layer 73 and the eighth passivation sub-layer 74 are hydrogenated passivation layers; the second direction is the direction from the silicon substrate 1 to the second transparent conductive layer 9.

[0118] The effects of the sub-layers in the second passivation layer 7 are the same as those of the sub-layers in the first passivation layer 2, and are not elaborated herein again in this application.

[0119] Further, as Figure 8 shown, the second doped silicon layer 8 includes a fourth doped sub-layer 81 disposed adjacent to the second passivation layer 7, and a fifth doped sub-layer 82, a sixth doped sub-layer 83, and a seventh doped sub-layer 84 successively disposed on the surface of the fourth doped sub-layer 81 facing away from the silicon substrate 1.

[0120] Among them, the thickness of the fourth doped sub-layer 81 is 0.1 nm to 1 nm; the thickness of the fifth doped sub-layer 82 is 5 nm to 10 nm; the thickness of the sixth doped sub-layer 83 is 8 nm to 15 nm; the thickness of the seventh doped sub-layer 84 is 8 nm to 15 nm.

[0121] In a second aspect, this application discloses a method for manufacturing a solar cell. The method for manufacturing a solar cell includes the following steps:

[0122] Prepare a first passivation layer on the light-receiving surface of the silicon substrate;

[0123] Prepare a patterned first doped silicon layer on a part of the first passivation layer;

[0124] Prepare a patterned dielectric layer on the remaining part of the first passivation layer not covered by the first doped silicon layer;

[0125] Prepare a first transparent conductive layer on the dielectric layer and the first doped silicon layer.

[0126] Optionally, when preparing film layers such as a passivation layer, a doped silicon layer, a dielectric layer, and a transparent conductive layer on a silicon substrate, at least one of Plasma-Enhanced Chemical Vapor Deposition (PECVD), Catalytic Chemical Vapor Deposition (CATCVD), High-Density Plasma Chemical Vapor Deposition (HDPCVD), Microwave Plasma Chemical Vapor Deposition (MPCVD), Ultra-High Vacuum Chemical Vapor Deposition (UHVCVD), and Physical Vapor Deposition (PVD) can be used.

[0127] Among them, the step of preparing a patterned first doped silicon layer on a part of the first passivation layer includes:

[0128] Preparing a first doped sub-layer on a part of the first passivation layer;

[0129] Preparing a second doped sub-layer on the first doped sub-layer;

[0130] Preparing a third doped sub-layer on the second doped sub-layer;

[0131] Preparing an oxygen-free contact layer on the third doped sub-layer.

[0132] In addition, taking the preparation of the patterned first doped silicon layer as an example, in an optional implementation manner, when preparing the patterned first doped silicon layer, a whole-layer first doped silicon layer is first prepared, and then a part of the first doped silicon layer is etched to remove this part of the first doped silicon layer, so as to obtain a patterned structure.

[0133] In another optional implementation manner, before preparing the patterned first doped silicon layer, a mask plate is first set on the first passivation layer, and then the first doped silicon layer is directly prepared. After the preparation, the mask plate is taken out, so as to obtain a patterned structure; compared with the etching method, the method using the mask plate has a simple process preparation process and high process controllability, which helps to ensure the film quality of the first doped silicon layer.

[0134] Among them, the patterned dielectric layer can also be prepared by the above method, and the present application will not elaborate here.

[0135] Further, in the step of preparing the first doped sub-layer, the preparation parameters include: the process gas includes SiH4, N2O, and H2, and the flow rate ratio of SiH4, N2O, and H2 is 1:1:250 to 1:8:350, the gas pressure is 4 Torr to 6 Torr, the glow power is 6000 W to 8000 W, and the glow time is 4 s to 10 s.

[0136] In the step of preparing the second doped sub-layer, the preparation parameters include: the process gas includes SiH4, N2O, the first doping gas source, and H2, and the flow rate ratio of SiH4, N2O, the first doping gas source, and H2 is 1:0.5:5:200 to 1:2:10:250, the gas pressure is 4 Torr to 6 Torr, the glow power is 8000 W to 12000 W, and the glow time is 30 s to 60 s.

[0137] In the step of preparing the third doped sub-layer, the preparation parameters include: the process gas includes SiH4, N2O, the first doping gas source, and H2, and the flow rate ratio of SiH4, N2O, the first doping gas source, and H2 is 1:0.5:7:180 to 1:2:15:220, the gas pressure is 4 Torr to 6 Torr, the glow power is 8000 W to 12000 W, and the glow time is 100 s to 150 s.

[0138] In the step of preparing the oxygen-free contact layer, the preparation parameters include: the process gas includes SiH4, the first doping gas source, and H2, and the flow rate ratio of SiH4, the first doping gas source, and H2 is 1:10:180 to 1:15:220, the gas pressure is 4 Torr to 6 Torr, the glow power is 8000 W to 12000 W, and the glow time is 20 s to 50 s.

[0139] By controlling the type and flow rate ratio of the process gas, the gas pressure, the glow power, and the glow time, the reaction sufficiency between the process gases is relatively high and the reaction rate is appropriate, ensuring that the prepared film layer has a relatively high density and fewer defects, thereby helping to reduce the recombination of carriers.

[0140] Optionally, the first doping gas source includes at least one of PH3, POCl3, P2O5, and P2O3. For example, the first doping gas source is a mixed gas source containing PH3, and the mixed gas source includes PH3 and H2, and the volume ratio of PH3 to H2 is 1%.

[0141] When a mixed gas source with a volume ratio of PH3 to H2 of 1% is selected as the first doping gas source, the doping ratio of boron in the first doping sub-layer to the third doping sub-layer is 5% to 15% at this time. Among them, the doping ratio = mixed gas source × 1% ÷ SiH4, and both the mixed gas source and SiH4 refer to the flow rate of the gas introduced.

[0142] Further, in the step of preparing the patterned dielectric layer on the remaining part of the first passivation layer not covered by the first doped silicon layer, the preparation parameters include: the process gas includes SiH4, an oxygen-containing gas, and H2, and the flow rate ratio of SiH4, the oxygen-containing gas, and H2 is 1:1:10 to 1:4:100, the gas pressure is 0.4 Torr to 0.7 Torr, the glow power is 500 W to 1500 W, and the glow time is 5 s to 20 s.

[0143] By controlling the preparation parameters of the dielectric layer within the above range, it helps to ensure that the prepared dielectric layer has high quality and helps to optimize the performance of the solar cell.

[0144] Further, the step of preparing the first passivation layer on the silicon substrate includes:

[0145] Preparing a first passivation sub-layer on the light-receiving surface of the silicon substrate;

[0146] Preparing a second passivation sub-layer on the first passivation sub-layer;

[0147] Preparing a third passivation sub-layer on the second passivation sub-layer;

[0148] Preparing a fourth passivation sub-layer on the third passivation sub-layer, where the first passivation sub-layer and the second passivation sub-layer are non-hydrogenated passivation layers, and the third passivation sub-layer and the fourth passivation sub-layer are hydrogenated passivation layers.

[0149] In an optional implementation manner, in the step of preparing the first passivation sub-layer, the preparation parameters include: the process gas includes SiH4 and an oxygen-containing gas, and the flow rate ratio of SiH4 and the oxygen-containing gas is 1:0.05 to 1:0.1, the gas pressure is 0.5 Torr to 0.7 Torr, the glow power is 1000 W to 2500 W, and the glow time is 1 s to 5 s.

[0150] In the step of preparing the second passivation sub-layer, the preparation parameters include: the process gas includes SiH4, and the flow rate of SiH4 is 1500 sccm to 2500 sccm, the gas pressure is 0.5 Torr to 0.7 Torr, the glow power is 200 W to 800 W, and the glow time is 1 s to 5 s.

[0151] In the step of preparing the third passivation sub-layer, the preparation parameters include: the process gas includes SiH4 and H2, and the flow ratio of SiH4 to H2 is 1:1 to 1:4, the gas pressure is 0.5 Torr to 0.7 Torr, the glow power is 500 W to 1000 W, and the glow time is 25 s to 35 s.

[0152] In the step of preparing the fourth passivation sub-layer, the preparation parameters include: the process gas includes SiH4 and H2, and the flow ratio of SiH4 to H2 is 1:1 to 1:25, the gas pressure is 0.5 Torr to 0.7 Torr, the glow power is 2500 W to 5000 W, and the glow time is 8 s to 15 s.

[0153] Among them, the oxygen-containing gas in the preparation of the first passivation sub-layer includes at least one of N2O, CO2, and O2.

[0154] By controlling the type and flow ratio of the process gas, the gas pressure, the glow power, and the glow time, the reaction sufficiency between the process gases is ensured to be relatively high and the reaction rate is appropriate, ensuring that the prepared film layer has a relatively high density, which helps to ensure the effect of the first passivation layer.

[0155] Further, before the step of preparing the first passivation layer on the light-receiving surface of the silicon substrate, the preparation method of the solar cell further includes: preparing a second passivation layer on the backlight surface of the silicon substrate, and the step of preparing the second passivation layer includes:

[0156] Preparing a fifth passivation sub-layer on the backlight surface of the silicon substrate;

[0157] Preparing a sixth passivation sub-layer on the fifth passivation sub-layer;

[0158] Preparing a seventh passivation sub-layer on the sixth passivation sub-layer;

[0159] Preparing an eighth passivation sub-layer on the seventh passivation sub-layer, where the fifth passivation sub-layer and the sixth passivation sub-layer are non-hydrogenated passivation layers, and the seventh passivation sub-layer and the eighth passivation sub-layer are hydrogenated passivation layers.

[0160] In an optional embodiment, in the step of preparing the fifth passivation sub-layer, the preparation parameters include: the process gas includes SiH4, and the SiH4 flow rate is 1500 sccm to 2500 sccm, the gas pressure is 0.5 Torr to 0.7 Torr, the glow power is 1000 W to 2500 W, and the glow time is 2 s to 6 s.

[0161] In the step of preparing the sixth passivation sub-layer, the preparation parameters include: the process gas includes SiH4, and the flow rate of SiH4 is 1500 sccm to 2500 sccm, the gas pressure is 0.3 Torr to 0.5 Torr, the glow power is 200 W to 800 W, and the glow time is 2 s to 10 s.

[0162] In the step of preparing the seventh passivation sub-layer, the preparation parameters include: the process gas includes SiH4 and H2, and the flow rate ratio of SiH4 to H2 is 1:1 to 1:4, the gas pressure is 0.5 Torr to 0.7 Torr, the glow power is 200 W to 600 W, and the glow time is 25 s to 50 s.

[0163] In the step of preparing the eighth passivation sub-layer, the preparation parameters include: the process gas includes SiH4 and H2, and the flow rate ratio of SiH4 to H2 is 1:1 to 1:25, the gas pressure is 0.5 Torr to 0.7 Torr, the glow power is 2500 W to 5000 W, and the glow time is 8 s to 15 s.

[0164] By controlling the preparation parameters within the above ranges, it helps to ensure that the prepared film layer has a high quality, thereby ensuring the passivation effect of the second passivation layer.

[0165] Further, a second passivation layer is provided on the backlight surface of the silicon substrate. After the step of preparing the patterned dielectric layer on the remaining part of the first passivation layer not covered by the first doped silicon layer, and before the step of preparing the first transparent conductive layer on the dielectric layer and the first doped silicon layer, the method for manufacturing a solar cell further includes: preparing a second doped silicon layer on the second passivation layer, and the step of preparing the second doped silicon layer includes:

[0166] Preparing a fourth doped sub-layer on the second passivation layer;

[0167] Preparing a fifth doped sub-layer on the fourth doped sub-layer;

[0168] Preparing a sixth doped sub-layer on the fifth doped sub-layer;

[0169] Preparing a seventh doped sub-layer on the sixth doped sub-layer.

[0170] In an optional embodiment, in the step of preparing the fourth doped sub-layer, the preparation parameters include: the process gas includes SiH4, N2O, a second doping gas source, and H2, and the flow rate ratio of SiH4, N2O, the second doping gas source, and H2 is 1:0.12:0.5:250 to 1:0.16:0.8:400, the gas pressure is 5 Torr to 7 Torr, the glow power is 6000 W to 10000 W, and the glow time is 2 s to 10 s.

[0171] In the step of preparing the fifth doped sub-layer, the preparation parameters include: the process gas includes SiH4, N2O, the second doping gas source and H2, and the flow rate ratio of SiH4, N2O, the second doping gas source and H2 is 1:0.08:0.2:200 to 1:0.12:0.5:300, the gas pressure is 5 Torr to 7 Torr, the glow power is 10000 W to 15000 W, and the glow time is 50 s to 100 s.

[0172] In the step of preparing the sixth doped sub-layer, the preparation parameters include: the process gas includes SiH4, N2O, the second doping gas source and H2, and the flow rate ratio of SiH4, N2O, the second doping gas source and H2 is 1:0.09:0.3:150 to 1:0.13:0.6:250, the gas pressure is 5 Torr to 7 Torr, the glow power is 10000 W to 15000 W, and the glow time is 80 s to 120 s.

[0173] In the step of preparing the seventh doped sub-layer, the preparation parameters include: the process gas includes SiH4, N2O, the second doping gas source and H2, and the flow rate ratio of SiH4, N2O, the second doping gas source and H2 is 1:0.1:0.4:100 to 1:0.14:0.8:200, the gas pressure is 5 Torr to 7 Torr, the glow power is 10000 W to 15000 W, and the glow time is 80 s to 120 s.

[0174] By controlling the preparation parameters within the above ranges, it helps to ensure that the prepared film layer has a high quality and has a good contact effect with the second passivation layer, thereby ensuring the carrier migration ability in the third doped silicon layer.

[0175] Optionally, the second doping gas source includes at least one of B2H6, BH3, BCl3, and TMB. For example, the second doping gas source is a mixed gas source containing B2H6. Among them, the mixed gas source includes B2H6 and H2, and the volume ratio of B2H6 to H2 is 2%.

[0176] When a mixed gas source with a volume ratio of B2H6 to H2 of 2% is selected as the second doping gas source, the doping ratio of boron in the fourth doped sub-layer to the seventh doped sub-layer is 0.4% to 1.6% at this time, where the doping ratio = mixed gas source × 2% ÷ SiH4, and both the mixed gas source and SiH4 refer to the flow rate of the gas introduced.

[0177] Further, a second doped silicon layer is provided on the backlit surface of the silicon substrate. After the step of preparing the first transparent conductive layer on the dielectric layer and the first doped silicon layer, the method for preparing a solar cell further includes:

[0178] A second transparent conductive layer is prepared on the second doped silicon layer;

[0179] A first electrode is prepared on the first transparent conductive layer;

[0180] A second electrode is prepared on the second transparent conductive layer.

[0181] Wherein, the first electrode and the second electrode are silver electrodes and / or copper electrodes. When it is a silver electrode, screen printing can be used for preparation; when it is a copper electrode, electroplating can be used for preparation.

[0182] In a third aspect, an embodiment of the present application discloses a photovoltaic module, which includes: the solar cell of the first aspect, or the solar cell prepared by the preparation method of the second aspect.

[0183] The technical solution of the present application will be further explained below in conjunction with more specific embodiments and experimental test results.

[0184] Embodiment 1:

[0185] Texturing is performed on the N-type silicon substrate.

[0186] A second passivation layer is prepared on the backlight side of the silicon substrate:

[0187] A fifth passivation sub-layer is prepared, and the process gas includes SiH4, and the SiH4 flow rate is 1900 sccm, the gas pressure is 0.6 Torr, the glow power is 1500 W, and the glow time is 4 s;

[0188] A sixth passivation sub-layer is prepared, and the process gas includes SiH4, and the SiH4 flow rate is 1900 sccm, the gas pressure is 0.4 Torr, the glow power is 600 W, and the glow time is 7 s;

[0189] A seventh passivation sub-layer is prepared, and the process gas includes SiH4 and H2, and the flow rate ratio of SiH4 and H2 is 1:2.5, the gas pressure is 0.6 Torr, the glow power is 400 W, and the glow time is 35 s;

[0190] An eighth passivation sub-layer is prepared, and the process gas includes SiH4 and H2, the flow rate ratio of SiH4 and H2 is 1:10, the gas pressure is 0.6 Torr, the glow power is 3500 W, and the glow time is 10 s.

[0191] A first passivation layer is prepared on the light-receiving surface of the silicon substrate, and the refractive index of the first passivation layer is 3.8:

[0192] Prepare the first passivation sub-layer. The process gas includes SiH4 and N2O, and the flow rate ratio of SiH4 to N2O is 1:0.08. The gas pressure is 0.6 Torr, the glow power is 1500 W, and the glow time is 3 s;

[0193] Prepare the second passivation sub-layer. The process gas includes SiH4, and the flow rate of SiH4 is 1900 sccm. The gas pressure is 0.6 Torr, the glow power is 600 W, and the glow time is 3 s;

[0194] Prepare the third passivation sub-layer. The process gas includes SiH4 and H2, and the flow rate ratio of SiH4 to H2 is 1:2.5. The gas pressure is 0.6 Torr, the glow power is 800 W, and the glow time is 29 s;

[0195] Prepare the fourth passivation sub-layer. The process gas includes SiH4 and H2, and the flow rate ratio of SiH4 to H2 is 1:10. The gas pressure is 0.6 Torr, the glow power is 4000 W, and the glow time is 10 s.

[0196] Place the mask on the first passivation layer, and use the mask to prepare a patterned first doped silicon layer on the first passivation layer, where the width of the first doped silicon layer is 35 μm, the thickness of the first doped silicon layer is 20 nm, and the doping concentration of the first doped silicon layer is 1×10 21 atoms / cm 3 :

[0197] Prepare the first doped sub-layer. The process gas includes SiH4, N2O, and H2, and the flow rate ratio of SiH4, N2O, and H2 is 1:4:300. The gas pressure is 5 Torr, the glow power is 7000 W, and the glow time is 6 s;

[0198] Prepare the second doped sub-layer. The process gas includes SiH4, N2O, PH3, and H2, and the flow rate ratio of SiH4, N2O, PH3, and H2 is 1:1:8:200. The gas pressure is 5 Torr, the glow power is 10000 W, and the glow time is 40 s;

[0199] In the step of preparing the third doped sub-layer, the process gas includes SiH4, N2O, PH3, and H2, and the flow rate ratio of SiH4, N2O, PH3, and H2 is 1:1:10:200. The gas pressure is 5 Torr, the glow power is 10000 W, and the glow time is 120 s;

[0200] In the step of preparing the oxygen-free contact layer, the process gas includes SiH4, PH3, and H2, and the flow rate ratio of SiH4, PH3, and H2 is 1:12:200, the gas pressure is 5 Torr, the starting power is 10,000 W, and the starting time is 30 s.

[0201] Replace the mask plate and prepare a dielectric layer on the first passivation layer. The material of the dielectric layer is hydrogenated silicon oxide. The process gas includes SiH4, N2O, and H2, and the flow rate ratio of SiH4, N2O, and H2 is 1:2:50, the starting power is 1,000 W, the starting time is 15 s, the thickness of the second doped silicon layer is 1.5 nm, and the refractive index of the dielectric layer is 2.0.

[0202] Prepare a second doped silicon layer on the second passivation layer:

[0203] Prepare a fourth doped sub-layer. The process gas includes SiH4, N2O, a second doping gas source, and H2, and the flow rate ratio of SiH4, N2O, the second doping gas source, and H2 is 1:0.14:0.7:300, the gas pressure is 6 Torr, the starting power is 9,000 W, and the starting time is 6 s;

[0204] Prepare a fifth doped sub-layer. The process gas includes SiH4, N2O, B2H6, and H2, and the flow rate ratio of SiH4, N2O, B2H6, and H2 is 1:0.1:0.3:250, the gas pressure is 6 Torr, the starting power is 12,000 W, and the starting time is 80 s;

[0205] Prepare a sixth doped sub-layer. The process gas includes SiH4, N2O, B2H6, and H2, and the flow rate ratio of SiH4, N2O, B2H6, and H2 is 1:0.1:0.4:180, the gas pressure is 6 Torr, the starting power is 12,000 W, and the starting time is 100 s;

[0206] Prepare a seventh doped sub-layer. The process gas includes SiH4, N2O, B2H6, and H2, and the flow rate ratio of SiH4, N2O, B2H6, and H2 is 1:0.13:0.6:150, the gas pressure is 6 Torr, the starting power is 12,000 W, and the starting time is 100 s.

[0207] Prepare a first transparent conductive layer on the first doped silicon layer and the dielectric layer. The refractive index of the first transparent conductive layer is 1.9.

[0208] Prepare a second transparent conductive layer on the third doped silicon layer;

[0209] Prepare a first electrode on the first transparent conductive layer. Among them, the width of the first electrode is 30 μm and the height is 15 μm;

[0210] The second electrode is fabricated on the second transparent conductive layer.

[0211] Example 2:

[0212] The difference between this example and Example 1 is only that the doping concentration of the first doped silicon layer is 1×10 20 atoms / cm 3 .

[0213] Example 3:

[0214] The difference between this example and Example 1 is only that the doping concentration of the first doped silicon layer is 1×10 19 atoms / cm 3 .

[0215] Example 4:

[0216] The difference between this example and Example 1 is only that the material of the dielectric layer is silicon nitride.

[0217] Example 5:

[0218] The difference between this example and Example 1 is only that the refractive index of the first passivation layer is 3, the refractive index of the dielectric layer is 1.6, and the refractive index of the first transparent conductive layer is 1.

[0219] Example 6:

[0220] The difference between this example and Example 1 is only that the width of the first doped silicon layer is 60 μm.

[0221] Comparative Example 1:

[0222] The difference between this comparative example and Example 1 is only that the first doped silicon layer is disposed as a whole layer on the first passivation layer, rather than a patterned first doped silicon layer, and no dielectric layer is provided.

[0223] Comparative Example 2:

[0224] The difference between this comparative example and Example 1 is only that no dielectric layer is provided, and the first transparent conductive layer is directly disposed on the first passivation layer not covered by the patterned first doped silicon layer.

[0225] Performance Test

[0226] The following relevant tests are carried out on the solar cells prepared in Examples 1 to 7 and Comparative Examples 1 to 2:

[0227] In this application, for a provided solar cell, a testing machine with the manufacturer being Zhongsen Electric Energy Technology Co., Ltd. and the model being GIV-60 is used to conduct performance tests on the solar cell in aspects such as open-circuit voltage, short-circuit current, and fill factor. The silicon wafer of the tested solar cell has a size of 210 mm×105 mm, and the calibrated light intensity is 1000±5 W / m². The experimental test results are as follows.

[0228] Table 1 Performance Test Results of Solar Cells

[0229]

[0230] By analyzing the data of Example 1 and Comparative Example 1, it can be seen that the photoelectric conversion performance of Example 1 is better than that of Comparative Example 1 because the first doped silicon layer in Example 1 is a patterned structure. This patterned design helps to reduce the parasitic absorption of light by the doped silicon layer, thereby highly improving the utilization rate of light and the photoelectric conversion performance of the solar cell.

[0231] By analyzing the data of Example 1 and Comparative Example 2, it can be seen that the photoelectric conversion performance of Example 1 is better than that of Comparative Example 2 because a dielectric layer is provided on the first passivation layer not covered by the patterned first doped silicon layer. The existence of this dielectric layer helps to reduce the damage to the first passivation layer during the preparation of the first transparent conductive layer, thereby highly ensuring the passivation effect of the first passivation layer; in addition, charge accumulation exists at the interface between the dielectric layer and the first doped silicon layer, increasing the intensity of the lateral electric field and improving the lateral transport ability of carriers.

[0232] By analyzing the data of Example 1, Example 3, and Example 4, it can be seen that the open-circuit voltage, fill factor, and photoelectric conversion efficiency of Example 1 and Example 3 are better than those of Example 4 because the doping concentrations of the first doped silicon layers in Example 1 and Example 3 are both in the range of 1×10 20 atoms / cm 3 ~5×10 21 atoms / cm 3 . Therefore, when the doping concentration is controlled within the above range, it can not only improve the transport ability of carriers but also help to generate a high electric field effect at the interface formed by the first doped silicon layer and the first passivation layer, thereby reducing the carrier recombination at the interface by using the high electric field effect and improving the performance of the solar cell.

[0233] By analyzing the data of Example 1 and Example 5, it can be seen that the photoelectric conversion performance of Example 1 is better than that of Example 5, indicating that when using silicon oxide as the dielectric layer, compared with silicon nitride, it is more helpful to further improve the utilization rate of light, thereby helping to further improve the performance of the solar cell.

[0234] Analysis of the data of Example 1 and Example 6 shows that the optoelectronic conversion performance of Example 1 is better than that of Example 6. It can be seen that when the refractive index is controlled under the conditions of Example 1, it is more conducive to the transmission of sunlight between layers, thereby helping to improve the utilization rate of sunlight to a higher degree and further improving the performance of the solar cell.

[0235] Analysis of the data of Example 1 and Example 7 shows that the optoelectronic conversion performance of Example 1 is better than that of Example 7. It can be seen that when the first doped silicon layer is in the range of 30 μm to 50 μm, it can not only further ensure the carrier transport performance in the first doped silicon layer, but also better avoid the aggravated recombination caused by the relatively high content of unactivated doping elements, thereby helping to further improve the optoelectronic conversion performance of the solar cell.

[0236] The solar cell, its preparation method, and the photovoltaic module disclosed in the embodiments of the present application have been introduced in detail above. Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The descriptions of the above embodiments are only used to help understand the solar cell, its preparation method, and the photovoltaic module. At the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A solar cell, characterized in that: The solar cell comprises: A silicon substrate, wherein the silicon substrate comprises a light-receiving surface and a backlight surface which are arranged opposite to each other; A first passivation layer, wherein the first passivation layer is disposed on the light receiving surface of the silicon substrate; a patterned first doped silicon layer, wherein the first doped silicon layer is located on a portion of the first passivation layer; a patterned dielectric layer, the dielectric layer being located on the remaining portion of the first passivation layer not covered by the first doped silicon layer; A first transparent conductive layer is located on the first doped silicon layer and the dielectric layer.

2. The solar cell according to claim 1, characterized in that: The thickness of the first doped silicon layer is greater than the thickness of the dielectric layer.

3. The solar cell according to claim 2, characterized in that: The thickness of the dielectric layer is 1 nm to 2 nm; and / or, The thickness of the first doped silicon layer is 10 nm to 30 nm.

4. The solar cell according to claim 2, characterized in that: The first transparent conductive layer located on the dielectric layer and the first transparent conductive layer located on the first doped silicon layer present a stepped structure.

5. The solar cell according to claim 1, characterized in that: The refractive indices of the first passivation layer, the dielectric layer, and the first transparent conductive layer show a decreasing trend.

6. The solar cell according to claim 5, characterized in that: The refractive index of the first passivation layer is 3.5-4.0; and / or, The refractive index of the dielectric layer is 1.8 to 2.2; and / or, The refractive index of the first transparent conductive layer is 1.7-2.

1.

7. The solar cell according to claim 1, characterized in that: The material of the dielectric layer includes at least one of silicon oxide, silicon nitride and silicon oxynitride; and / or, The doping concentration of the first doped silicon layer is 1×10 20 atoms / cm 3 ~5×10 21 atoms / cm 3 and / or, Along a first direction, the width of the first doped silicon layer is 30 μm to 50 μm, and the first direction is perpendicular to the thickness direction of the solar cell.

8. The solar cell according to claim 7, characterized in that: Along the second direction, the first doped silicon layer includes in sequence: a first doped sublayer, a second doped sublayer, a third doped sublayer and an oxygen-free contact layer, and the second direction is from the silicon substrate to the first transparent conductive layer; Wherein, the thickness of the first doped sublayer is 0.2 nm to 1 nm; and / or, The thickness of the second doped sublayer is 3 nm to 6 nm; and / or, The thickness of the third doped sublayer is 10 nm to 15 nm; and / or, The thickness of the oxygen-free contact layer is 2 nm to 5 nm.

9. The solar cell according to claim 1, characterized in that: The solar cell further comprises a first electrode, which is arranged on a surface of the first transparent conductive layer facing away from the silicon substrate; In the plane direction of the solar cell, the orthographic projection pattern of the first electrode is located within the orthographic projection pattern of the first doped silicon layer.

10. The solar cell according to claim 1, characterized in that: Along the second direction, the first passivation layer includes a first passivation sublayer, a second passivation sublayer, a third passivation sublayer and a fourth passivation sublayer in sequence, wherein the first passivation sublayer and the second passivation sublayer are non-hydrogenated passivation layers, and the third passivation sublayer and the fourth passivation sublayer are hydrogenated passivation layers; the second direction is the direction from the silicon substrate to the first transparent conductive layer.

11. The solar cell according to any one of claims 1 to 10, characterized in that: The backlight surface of the silicon substrate is provided with a second passivation layer, and a second doped silicon layer, a second transparent conductive layer and a second electrode are sequentially arranged on a surface of the second passivation layer facing away from the silicon substrate.

12. A method for preparing a solar cell, characterized in that: The preparation method comprises the following steps: Preparing a first passivation layer on the light-receiving surface of the silicon substrate; forming a patterned first doped silicon layer on a portion of the first passivation layer; preparing a patterned dielectric layer on the remaining portion of the first passivation layer not covered by the first doped silicon layer; A first transparent conductive layer is prepared on the dielectric layer and the first doped silicon layer.

13. The preparation method according to claim 12, characterized in that: The step of preparing a patterned first doped silicon layer on a portion of the first passivation layer comprises: preparing a first doped sublayer on a portion of the first passivation layer; preparing a second doped sublayer on the first doped sublayer; preparing a third doped sublayer on the second doped sublayer; An oxygen-free contact layer is prepared on the third doped sublayer.

14. The preparation method according to claim 13, characterized in that: In the step of preparing the first doped sublayer, the preparation parameters include: the process gas includes SiH4, N2O and H2, and the flow ratio of SiH4, N2O and H2 is 1:1:250~1:8:350, the gas pressure is 4 Torr~6 Torr, the ignition power is 6000 W~8000 W, and the ignition time is 4 s~10 s; and / or, In the step of preparing the second doped sublayer, the preparation parameters include: the process gas includes SiH4, N2O, a first doping gas source and H2, and the flow ratio of SiH4, N2O, the first doping gas source and H2 is 1:0.5:5:200~1:2:10:250, the gas pressure is 4 Torr~6 Torr, the ignition power is 8000 W~12000 W, and the ignition time is 30 s~60 s; and / or, In the step of preparing the third doped sublayer, the preparation parameters include: the process gas includes SiH4, N2O, a first doping gas source and H2, and the flow ratio of SiH4, N2O, the first doping gas source and H2 is 1:0.5:7:180~1:2:15:220, the gas pressure is 4 Torr~6 Torr, the ignition power is 8000 W~12000 W, and the ignition time is 100 s~150 s; and / or, In the step of preparing the oxygen-free contact layer, the preparation parameters include: the process gas includes SiH4, a first doping gas source and H2, and the flow ratio of SiH4, the first doping gas source and H2 is 1:10:180~1:15:220, the gas pressure is 4 Torr~6Torr, the ignition power is 8000 W~12000 W, and the ignition time is 20 s~50 s.

15. The preparation method according to claim 12, characterized in that: In the step of preparing a patterned dielectric layer on the remaining portion of the first passivation layer not covered by the first doped silicon layer, preparation parameters include: process gases include SiH4, oxygen-containing gas and H2, and the flow ratio of SiH4, the oxygen-containing gas and H2 is 1:1:10~1:4:100, the gas pressure is 0.4 Torr~0.7 Torr, the ignition power is 500 W~1500 W, and the ignition time is 5 s~20 s.

16. The preparation method according to any one of claims 12 to 15, characterized in that: Before the step of preparing the first passivation layer on the light-receiving surface of the silicon substrate, the method for preparing a solar cell further comprises: preparing a second passivation layer on the backlight surface of the silicon substrate; and / or, A second passivation layer is arranged on the backlight surface of the silicon substrate, and before the step of preparing the first transparent conductive layer on the dielectric layer and the first doped silicon layer, and after the step of preparing a patterned dielectric layer on the remaining portion of the first passivation layer not covered by the first doped silicon layer, the method for preparing a solar cell further includes: preparing a second doped silicon layer on the second passivation layer; and / or, A second doped silicon layer is disposed on the backlight surface of the silicon substrate. After the step of preparing a first transparent conductive layer on the dielectric layer and the first doped silicon layer, the method for preparing a solar cell further includes: preparing a second transparent conductive layer on the second doped silicon layer; preparing a first electrode on the first transparent conductive layer; A second electrode is formed on the second transparent conductive layer.

17. A photovoltaic module, characterized in that: The photovoltaic module comprises: the solar cell according to any one of claims 1 to 11, or the solar cell prepared by the preparation method according to any one of claims 12 to 16.

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