Solar cell, preparation method thereof and photovoltaic module

Abstract

The invention relates to the technical field of solar cells, and discloses a solar cell and a preparation method thereof, and a photovoltaic module, the solar cell comprises a silicon substrate, the silicon substrate comprises a light receiving surface and a backlight surface which are arranged back to back; the first passivation layer is arranged 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 part of the first passivation layer; the dielectric layer is positioned on the rest part of the first passivation layer which is not covered with the first doped silicon layer; and the first transparent conductive layer is positioned 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 the first doped silicon layer to light can be effectively reduced, the recombination of current carriers is reduced, the short-circuit current of the solar cell is increased, and the photoelectric conversion efficiency of the solar cell is optimized.

Description

Technical Field

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

[0002] The utilization rate of sunlight by solar cells is a key factor affecting the performance of solar cells. Taking heterojunction solar cells as an example, a doped silicon layer is arranged on the light-receiving surface of heterojunction solar cells. The doped silicon layer has light absorption characteristics, which will affect the absorption of light by the solar cell, making the solar cell have a higher parasitic absorption of light, which will lead to a decrease 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] The embodiment of the present invention discloses a solar cell and a preparation method thereof, and a photovoltaic module. The solar cell can effectively reduce the parasitic absorption of light by a 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, an embodiment of the present application discloses a solar cell, the solar cell comprising: 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.

[0005] Furthermore, the thickness of the first doped silicon layer is greater than the thickness of the dielectric layer.

[0006] Further, 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.

[0007] Furthermore, 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.

[0008] Furthermore, the refractive indices of the first passivation layer, the dielectric layer, and the first transparent conductive layer show a decreasing trend.

[0009] Further, 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.

[0010] Further, 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.

[0011] Further, 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 a direction 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.

[0012] Furthermore, 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.

[0013] 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.

[0014] 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.

[0015] In a second aspect, the present application discloses a method for preparing a solar cell, the method comprising 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.

[0016] Furthermore, 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.

[0017] 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, 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 4Torr~6 Torr, the ignition power is 8000 W~12000 W, and the ignition time is 20 s~50 s.

[0018] Furthermore, 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, the preparation parameters include: the process gas includes 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 starting power is 500 W~1500 W, and the starting time is 5 s~20 s.

[0019] Furthermore, before the step of preparing a patterned first doped silicon layer on part of the first passivation layer and after the step of preparing a first passivation layer on the light-receiving surface of the silicon substrate, the method for preparing a solar cell further includes: preparing the second passivation layer on the backlight surface of the silicon substrate; and / or, A second passivation layer is disposed on the backlight surface of the silicon substrate. Before 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 comprises: preparing a second doped silicon layer on the second passivation layer; and / or, After the step of preparing the first transparent conductive layer on the dielectric layer and the first doped silicon layer, the method for preparing the 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.

[0020] In a third aspect, an embodiment of the present application discloses a photovoltaic module, which includes: the solar cell described in any one of the first aspects, or the solar cell prepared by the preparation method described in any one of the second aspects.

[0021] Compared with the prior art, the beneficial effects of this application are: The present application provides a solar cell and a preparation method thereof, and a photovoltaic module, wherein the light-receiving surface of the silicon substrate is provided with a first passivation layer, a patterned first doped silicon layer, a patterned dielectric layer, and a first transparent conductive layer in sequence. 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.

[0022] Specifically, a patterned first doped silicon layer and a patterned dielectric layer are arranged on the first passivation layer. Therefore, due to the different energy bands of the dielectric layer and the first doped silicon layer, charge accumulation occurs at their interface, which increases the strength of the lateral electric field, reduces the recombination of carriers at the interface, and improves the lateral transmission capacity of carriers. In addition, since the patterned first doped silicon layer has a small coverage area on the silicon substrate, the parasitic absorption of sunlight by the first doped silicon layer can be effectively reduced, thereby improving the short-circuit current of the solar cell.

[0023] 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 transmission barrier of carriers and reduce the recombination of carriers at the interface; and the dielectric layer can also effectively avoid 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 is a schematic diagram of the structure of a solar cell provided in an embodiment of the present application; Figure 2 is a schematic structural diagram of a first doped silicon layer and a dielectric layer provided in an embodiment of the present application; Figure 3 is a schematic diagram of the structure of another first doped silicon layer and a dielectric layer provided in an embodiment of the present application; Figure 4 is a schematic structural diagram of a light-receiving surface of a silicon substrate (the first electrode is not shown) provided in an embodiment of the present application; Figure 5is a schematic structural diagram of a solar cell including an enlarged view of a first doped silicon layer provided in an embodiment of the present application; Figure 6 is a schematic structural diagram of a solar cell including an enlarged view of a first passivation layer provided in an embodiment of the present application; Figure 7 is a schematic structural diagram of a solar cell including an enlarged view of a second passivation layer provided in an embodiment of the present application; Figure 8 It is a schematic diagram of the structure of a solar cell including an enlarged view of a second doped silicon layer provided in an embodiment of the present application.

[0026] Icons: 1. Silicon substrate; 1a. Light-receiving surface; 1b. Backlight surface; 2. First passivation layer; 21. First passivation sublayer; 22. Second passivation sublayer; 23. Third passivation sublayer; 24. Fourth passivation sublayer; 3. First doped silicon layer; 31. First doped sublayer; 32. Second doped sublayer; 33. Third doped sublayer; 34. Oxygen-free contact layer; 4. Dielectric layer; 5. First transparent conductive layer; 6. First electrode; 7. Second passivation layer; 71. Fifth passivation sublayer; 72. Sixth passivation sublayer; 73. Seventh passivation sublayer; 74. Eighth passivation sublayer; 8. Second doped silicon layer; 81. Fourth doped sublayer; 82. Fifth doped sublayer; 83. Sixth doped sublayer; 84. Seventh doped sublayer; 9. Second transparent conductive layer; 10. Second electrode. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the present invention, the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like are based on the directions or positional relationships shown in the drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0029] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0030] In addition, the terms "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, "plurality" means two or more.

[0031] The technical solution provided by the present invention will be further described below in conjunction with embodiments and drawings.

[0032] The utilization rate of sunlight by solar cells is a key factor affecting the performance of solar cells. Taking heterojunction solar cells as an example, a doped silicon layer is set on the light-receiving surface of heterojunction solar cells, but the presence of the doped silicon layer will produce serious parasitic absorption, which will lead to a decrease in the utilization rate of sunlight and an increase in the recombination of carriers, making it difficult to more effectively improve the photoelectric conversion performance of solar cells.

[0033] This is because, on the one hand, due to the presence of doping elements in the doped silicon layer, these doping elements will produce impurity energy levels, allowing carriers to transition to impurity energy levels during transitions, thereby producing parasitic absorption; on the other hand, due to the difference in the lattice between the doping elements and the silicon atoms, it will cause partial silicon lattice distortion, thereby producing parasitic absorption.

[0034] 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.

[0035] The first aspect, such as Figure 1 As shown, the embodiment of the present application discloses a solar cell, the solar cell comprising: A silicon substrate 1, wherein the silicon substrate 1 comprises a light-receiving surface 1a and a backlight surface 1b which are arranged opposite to each other; A first passivation layer 2, the first passivation layer 2 is disposed on the light receiving surface 1a of the silicon substrate 1; A patterned first doped silicon layer 3, wherein the first doped silicon layer 3 is located on a portion of the first passivation layer 2; A patterned dielectric layer 4, the dielectric layer 4 being located on the remaining portion of the first passivation layer 2 not covered by the first doped silicon layer 3; The first transparent conductive layer 5 is located on the first doped silicon layer 3 and the dielectric layer 4 .

[0036] The patterned first doped silicon layer 3 means that only a part of 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 first passivation layer 2 is provided with the dielectric layer 4 .

[0037] The present application arranges a patterned first doped silicon layer 3 and a patterned dielectric layer 4 on the first passivation layer 2, and utilizes the synergistic effect of the two to reduce the parasitic absorption of the first doped silicon layer 3 to a high degree, reduce the recombination of carriers, increase the short-circuit current of the solar cell, and optimize the photoelectric conversion efficiency of the solar cell.

[0038] The present application prepares a patterned first doped silicon layer 3 on the first passivation layer 2, thereby helping to reduce the parasitic absorption of the first doped silicon layer 3, improve the utilization rate of sunlight, and improve the short-circuit current. However, the applicant has found that reducing the area of ​​the first doped silicon layer 3 on the first passivation layer 2 helps to reduce the parasitic absorption of the light-receiving surface, but the patterned first doped silicon layer 3 causes an increase in the boundaries of the first doped silicon layer 3, and the increase in boundaries may produce more defects, increasing the recombination of carriers at the boundaries; and the patterned first doped silicon layer 3 will also cause part of the first passivation layer 2 to directly contact the first transparent conductive layer 5, so that the contact performance between the first transparent conductive layer 5 and the first passivation layer 2 deteriorates; in addition, when the first transparent conductive layer 5 is directly provided on the first passivation layer 2, the structure of the first passivation layer 2 will also be destroyed during the preparation of the first transparent conductive layer 5. Therefore, the present application further provides a patterned dielectric layer 4, thereby helping to reduce the recombination of carriers and improve the performance of solar cells.

[0039] Among them, by respectively arranging 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, charge accumulation occurs at their interface, which increases the intensity of the lateral electric field, reduces the recombination of carriers at the interface, and improves the lateral transmission capability of carriers to a greater extent.

[0040] 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 mismatching the work functions of the first passivation layer 2 and the first transparent conductive layer 5, which helps to reduce the transmission barrier of carriers and reduce the recombination of carriers at the interface; and the dielectric layer 4 can also effectively prevent the first transparent conductive layer 5 from damaging the first passivation layer 2, thereby ensuring the passivation effect of the first passivation layer 2 to a high degree. In addition, the dielectric layer 4 can also passivate the defects on the first passivation layer 2, thereby reducing the recombination of carriers to a high degree and improving the performance of the solar cell.

[0041] In addition, for the first doped silicon layer 3 of the present application, the first doped silicon layer 3 of the present application is one of an N-type semiconductor layer or a P-type semiconductor layer, which is achieved by adding doping elements to the silicon material, thereby changing 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 absorbing light. Therefore, in order to reduce the parasitic absorption of the first doped silicon layer 3, the present application reduces the coverage area of ​​the first doped silicon layer 3 on the first passivation layer 2 by setting a patterned first doped silicon layer 3, thereby reducing the parasitic absorption.

[0042] However, the patterned first doped silicon layer 3 will also make part of the first passivation layer 2 directly 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 destroyed during the preparation of the first transparent conductive layer 5. Therefore, in order to avoid additional parasitic absorption and to further improve the contact performance and protect the first passivation layer 2, the present application sets a dielectric layer 4 between the first passivation layer 2 and the first transparent conductive layer 5.

[0043] Therefore, for the dielectric layer 4, in order to avoid parasitic absorption and improve contact performance and protect the film structure of the first passivation layer 2, the material of the dielectric layer 4 should be different from the first doped silicon layer 3, so that there is a difference in the energy bands of the dielectric layer 4 and the first doped silicon layer 3.

[0044] Specifically, the material of the dielectric layer 4 includes at least one of silicon oxide, silicon nitride, and silicon oxynitride. When the above materials are selected as the dielectric layer 4, the dielectric layer 4 has the effect of protecting the first passivation layer 2; in addition, when the above materials are selected as the dielectric layer 4, the dielectric layer 4 has a higher anti-reflection effect, which can further improve the utilization rate of light and improve 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 helps to improve the utilization rate of light.

[0045] 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.

[0046] In addition, the passivation layer includes an intrinsic amorphous silicon layer; and 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.

[0047] In an optional embodiment, if Figure 2 As shown, the thickness of the first doped silicon layer 3 is the same as the thickness of the dielectric layer 4, that is, the surface of the first doped silicon layer 3 away from the first passivation layer 2 is flush with the surface of the dielectric layer 4 away from the first passivation layer 2. In another optional embodiment, as Figure 3As shown, the thickness of the first doped silicon layer 3 is greater than the thickness of the dielectric layer 4, that is, the surface of the first doped silicon layer 3 away from the first passivation layer 2 is higher than the surface of the dielectric layer 4 away from the first passivation layer 2, so that a step-like structure is formed between the two. In this embodiment, on the one hand, the dielectric layer 4 is thin, which is conducive to the transmission of carriers; on the other hand, the step-like 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 part of the 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, thereby helping to provide more carrier transmission channels.

[0048] The thickness of the dielectric layer 4 is 1 nm to 2 nm. When the dielectric layer 4 is at this thickness, it is helpful for the tunneling of carriers and further shortens the propagation distance of light. For example, the thickness of the dielectric layer 4 is 1 nm, 1.2 nm, 1.5 nm, 1.8 nm or 2 nm.

[0049] 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 contributes to the carrier transmission capability 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.

[0050] In addition, thickness refers to 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. It reflects the overall thickness level of the doped silicon layer in the thickness direction.

[0051] In addition, an ellipsometer is used to test the thickness of the doped silicon layer. At least five points are taken on the doped silicon layer, and the thickness values ​​of the five points are measured respectively, so as to obtain the average value of the measured data. For example, an ellipsometer of SE-800 manufactured by German Sentch Company can be used to test the film thickness. The present application does not limit the specific method of the test, as long as the purpose of the present application can be achieved.

[0052] Furthermore, if Figure 4 As 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.

[0053] In an optional 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, wherein, 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, and therefore when the first transparent conductive layer 5 is deposited on the stepped structure, it presents a stepped structure.

[0054] Furthermore, the refractive indexes of the first passivation layer 2, the dielectric layer 4 and the first transparent conductive layer 5 show a decreasing trend. As the refractive index shows a decreasing trend, the utilization rate of light by the solar cell is improved.

[0055] In addition, the refractive index of the first passivation layer 2 is 3.5-4.0, the refractive index of the dielectric layer 4 is 1.8-2.2, and the refractive index of the first transparent conductive layer 5 is 1.7-2.1. When the refractive indexes of the first passivation layer 2, the dielectric layer 4, and the first transparent conductive layer 5 are within the above range, the matching degree between the layers is higher, which helps to further improve the utilization rate of sunlight.

[0056] Furthermore, the doping concentration of the first doped silicon layer 3 is 1×10 20 atoms / cm 3 ~5×10 21 atoms / cm 3 .

[0057] When the doping concentration of the first doped silicon layer 3 is within the above range, the surface field passivation effect is strong, so that the interface between the first passivation layer 2 and the first doped silicon layer 3 has a higher electric field effect, thereby improving the carrier transmission performance. For example, 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 wait.

[0058] The doping concentration indicates the content of the doping elements added to the doped silicon layer, and refers to the total doping concentration in the doped silicon layer. The doping element refers to the element added to the doped silicon layer in order to change the conductivity type of the doped silicon layer. For solar cells, the conductivity 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.

[0059] In addition, when the doped silicon layer is a structure in which multiple sub-layers are stacked, the doping concentration refers to the sum of the doping concentrations of the multiple sub-layers.

[0060] 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 method of the test, as long as the purpose of the present application can be achieved.

[0061] In an optional embodiment, if Figure 5 As shown, along the second direction (see Figure 5 In the Y1 direction in the figure), the first doped silicon layer 3 includes: a first doped sublayer 31, a second doped sublayer 32, a third doped sublayer 33 and an oxygen-free contact layer 34 in sequence, and the second direction is the direction from the silicon substrate 1 to the first transparent conductive layer 5; wherein the thickness of the first doped sublayer 31 is 0.2 nm~1 nm; the thickness of the second doped sublayer 32 is 3 nm~6 nm; the thickness of the third doped sublayer 33 is 10 nm~15 nm; the thickness of the oxygen-free contact layer 34 is 2 nm~5 nm.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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 .

[0066] 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.

[0067] In addition, when the first electrode 6 is arranged 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, since the width of the first doped silicon layer of 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 is helpful to improve the accuracy of processing and ensure the effectiveness of the preparation of the first electrode 6.

[0068] Furthermore, if Figure 6 As shown, along the second direction, the first passivation layer 2 includes a first passivation sublayer 21, a second passivation sublayer 22, a third passivation sublayer 23 and a fourth passivation sublayer 24 in sequence, wherein the first passivation sublayer 21 and the second passivation sublayer 22 are non-hydrogenated passivation layers, and the third passivation sublayer 23 and the fourth passivation sublayer 24 are hydrogenated passivation layers; the second direction is the direction from the silicon substrate 1 to the first transparent conductive layer 5.

[0069] Among them, the non-hydrogenated passivation layer refers to a film layer formed by not introducing an additional hydrogen source during the preparation process, for example, no hydrogen is introduced during the preparation process; the hydrogenated passivation layer refers to a film layer formed by introducing an additional hydrogen source during the preparation process, for example, hydrogen is introduced as a reaction gas during the preparation process.

[0070] Therefore, since the first passivation sublayer 21 and the second passivation sublayer 22 are non-hydrogenated passivation layers and no additional hydrogen source is introduced during preparation, the density of the film layer is relatively high. Therefore, the first passivation sublayer 21 can effectively prevent epitaxial growth and has good contact with the silicon substrate 1; the second passivation sublayer 22 can react with the unreacted groups in the first passivation sublayer 21, thereby reducing the accumulation of yellow powder; the third passivation sublayer 23 and the fourth passivation sublayer 24 are hydrogenated passivation layers, containing more hydrogen elements. On the one hand, the hydrogen elements in the third passivation sublayer 23 and the fourth passivation sublayer 24 can be used to further improve the passivation effect, and on the other hand, the crystallization rate of the fourth passivation sublayer 24 can be improved, so that it has better contact performance with the first doped silicon layer 3 and the second doped silicon layer 8, thereby utilizing the high field strength of the first doped silicon layer 3 to a higher extent and improving the carrier transmission capacity.

[0071] Further, the thickness of the first passivation sublayer 21 is 0.5 nm to 3 nm; the thickness of the second passivation sublayer 22 is 0.1 nm to 1 nm; the thickness of the third passivation sublayer 23 is 2 nm to 6 nm; and the thickness of the fourth passivation sublayer 24 is 0.5 nm to 2 nm.

[0072] For further information, see Figure 1 The backlight surface 1 b of the silicon substrate 1 is provided with a second passivation layer 7 , 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 .

[0073] Furthermore, if Figure 7 As shown, along the second direction (see Figure 7 ), the second passivation layer 7 sequentially includes a fifth passivation sublayer 71, a sixth passivation sublayer 72, a seventh passivation sublayer 73 and an eighth passivation sublayer 74, wherein the fifth passivation sublayer 71 and the sixth passivation sublayer 72 are non-hydrogenated passivation layers, and the seventh passivation sublayer 73 and the eighth passivation sublayer 74 are hydrogenated passivation layers; the second direction is the direction from the silicon substrate 1 to the second transparent conductive layer 9.

[0074] The effects of each sublayer in the second passivation layer 7 are consistent with the effects of each sublayer in the first passivation layer 2 , and will not be described in detail in this application.

[0075] Furthermore, if Figure 8 As shown, the second doped silicon layer 8 includes a fourth doped sublayer 81 disposed close to the second passivation layer 7 , and a fifth doped sublayer 82 , a sixth doped sublayer 83 and a seventh doped sublayer 84 disposed sequentially on the surface of the fourth doped sublayer 81 facing away from the silicon substrate 1 .

[0076] Among them, the thickness of the fourth doped sublayer 81 is 0.1 nm to 1 nm; the thickness of the fifth doped sublayer 82 is 5 nm to 10 nm; the thickness of the sixth doped sublayer 83 is 8 nm to 15 nm; and the thickness of the seventh doped sublayer 84 is 8 nm to 15 nm.

[0077] In a second aspect, the present application discloses a method for preparing a solar cell, the method for preparing a solar cell comprising 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.

[0078] Optionally, when preparing a passivation layer, a doped silicon layer, a dielectric layer, a transparent conductive layer and other film layers 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.

[0079] The step of preparing a patterned first doped silicon layer on a portion of the first passivation layer includes: 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 formed on the third doped sublayer.

[0080] In addition, taking the preparation of a patterned first doped silicon layer as an example, in an optional embodiment, when preparing the patterned first doped silicon layer, a whole layer of the first doped silicon layer is first prepared, and then part of the first doped silicon layer is etched to remove the part of the first doped silicon layer, thereby obtaining a patterned structure.

[0081] In another optional embodiment, before preparing the patterned first doped silicon layer, a mask is first set on the first passivation layer, and then the first doped silicon layer is directly prepared. After the preparation, the mask is taken out to obtain a patterned structure; compared with the etching method, the method using the mask has a simple process preparation process and high process controllability, which helps to ensure the film quality of the first doped silicon layer.

[0082] Among them, the patterned dielectric layer can also be prepared by the above method, which will not be described in detail in this application.

[0083] Furthermore, 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 starting power is 6000 W~8000 W, and the starting time is 4 s~10 s.

[0084] 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 starting power is 8000 W~12000 W, and the starting time is 30 s~60 s.

[0085] 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 starting power is 8000 W~12000 W, and the starting time is 100 s~150 s.

[0086] 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 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.

[0087] By controlling the type and flow ratio of process gases, gas pressure, ignition power and ignition time, the reaction between process gases can be highly sufficient and the reaction rate can be appropriate, ensuring that the prepared film layer has high density and fewer defects, which helps to reduce carrier recombination.

[0088] 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%.

[0089] When a mixed gas source with a volume ratio of 1% of PH3 and H2 is selected as the first doping gas source, the doping ratio of boron in the first to third doping sublayers is 5%~15%, wherein the doping ratio = mixed gas source × 1% ÷ SiH4, and the mixed gas source and SiH4 both refer to the flow rate of the introduced gas.

[0090] Furthermore, 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, the preparation parameters include: the process gas includes SiH4, oxygen-containing gas and H2, and the flow ratio of SiH4, 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.

[0091] 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.

[0092] Furthermore, the step of preparing a first passivation layer on the silicon substrate includes: preparing a first passivation sublayer on the light-receiving surface of the silicon substrate; preparing a second passivation sublayer on the first passivation sublayer; preparing a third passivation sublayer on the second passivation sublayer; A fourth passivation sublayer is prepared on the third passivation sublayer, 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.

[0093] In an optional embodiment, in the step of preparing the first passivation sublayer, the preparation parameters include: the process gas includes SiH4 and oxygen-containing gas, and the flow ratio of SiH4 and the oxygen-containing gas is 1:0.05~1:0.1, the gas pressure is 0.5Torr~0.7 Torr, the starting power is 1000 W~2500 W, and the starting time is 1 s~5 s.

[0094] In the step of preparing the second passivation sublayer, the preparation parameters include: the process gas includes SiH4, and the SiH4 flow rate is 1500 sccm~2500 sccm, the gas pressure is 0.5 Torr~0.7 Torr, the ignition power is 200 W~800 W, and the ignition time is 1 s~5 s.

[0095] In the step of preparing the third passivation sublayer, the preparation parameters include: the process gas includes SiH4 and H2, and the flow ratio of SiH4 and H2 is 1:1 ~1:4, the gas pressure is 0.5 Torr ~ 0.7 Torr, the ignition power is 500 W ~ 1000 W, and the ignition time is 25 s ~ 35 s.

[0096] In the step of preparing the fourth passivation sublayer, the preparation parameters include: the process gas includes SiH4 and H2, and the flow ratio of SiH4 and H2 is 1:1~1:25, the gas pressure is 0.5 Torr~0.7 Torr, the ignition power is 2500 W~5000 W, and the ignition time is 8 s~15 s.

[0097] Wherein, the oxygen-containing gas used in preparing the first passivation sublayer includes at least one of N2O, CO2, and O2.

[0098] By controlling the type and flow ratio of process gases, gas pressure, ignition power and ignition time, the reaction between process gases can be ensured to be highly sufficient and at an appropriate reaction rate, and the density of the prepared film layer can be ensured, which helps to ensure the effect of the first passivation layer.

[0099] Furthermore, before the step of preparing the first passivation layer on the light-receiving surface of the silicon substrate, the method for preparing 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: Prepare a fifth passivation sublayer on the backlight surface of the silicon substrate; preparing a sixth passivation sublayer on the fifth passivation sublayer; preparing a seventh passivation sublayer on the sixth passivation sublayer; An eighth passivation sublayer is prepared on the seventh passivation sublayer, wherein the fifth passivation sublayer and the sixth passivation sublayer are non-hydrogenated passivation layers, and the seventh passivation sublayer and the eighth passivation sublayer are hydrogenated passivation layers.

[0100] In an optional embodiment, in the step of preparing the fifth passivation sublayer, the preparation parameters include: the process gas includes SiH4, and the SiH4 flow rate is 1500 sccm~2500 sccm, the gas pressure is 0.5 Torr~0.7 Torr, the ignition power is 1000 W~2500 W, and the ignition time is 2 s~6 s.

[0101] In the step of preparing the sixth passivation sublayer, the preparation parameters include: the process gas includes SiH4, and the SiH4 flow rate is 1500 sccm~2500 sccm, the gas pressure is 0.3 Torr~0.5 Torr, the ignition power is 200 W~800 W, and the ignition time is 2 s~10 s.

[0102] In the step of preparing the seventh passivation sublayer, the preparation parameters include: the process gas includes SiH4 and H2, and the flow ratio of SiH4 and H2 is 1:1 ~1:4, the gas pressure is 0.5 Torr ~ 0.7 Torr, the ignition power is 200 W ~ 600 W, and the ignition time is 25 s ~ 50 s.

[0103] In the step of preparing the eighth passivation sublayer, the preparation parameters include: the process gas includes SiH4 and H2, and the flow ratio of SiH4 and H2 is 1:1~1:25, the gas pressure is 0.5 Torr~0.7 Torr, the ignition power is 2500 W~5000 W, and the ignition time is 8 s~15 s.

[0104] By controlling the preparation parameters within the above range, it helps to ensure that the prepared film layer has high quality, thereby ensuring the passivation effect of the second passivation layer.

[0105] Furthermore, a second passivation layer is provided on the backlight surface of the silicon substrate, 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, and before 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 doped silicon layer on the second passivation layer, and the step of preparing the second doped silicon layer includes: preparing a fourth doped sublayer on the second passivation layer; forming a fifth doped sublayer on the fourth doped sublayer; forming a sixth doped sublayer on the fifth doped sublayer; A seventh doped sublayer is formed on the sixth doped sublayer.

[0106] In an optional embodiment, in the step of preparing the fourth doped sublayer, the preparation parameters include: the process gas includes SiH4, N2O, a second doping gas source and H2, and the flow ratio of SiH4, N2O, the second doping gas source and H2 is 1:0.12:0.5:250~1:0.16:0.8:400, the gas pressure is 5 Torr~7 Torr, the starting power is 6000 W~10000 W, and the starting time is 2 s~10 s.

[0107] In the step of preparing the fifth doped sublayer, the preparation parameters include: the process gas includes SiH4, N2O, a second doping gas source and H2, and the flow ratio of SiH4, N2O, the second doping gas source and H2 is 1:0.08:0.2:200~1:0.12:0.5:300, the gas pressure is 5 Torr~7 Torr, the starting power is 10000 W~15000 W, and the starting time is 50 s~100 s.

[0108] In the step of preparing the sixth doped sublayer, the preparation parameters include: the process gas includes SiH4, N2O, a second doping gas source and H2, and the flow ratio of SiH4, N2O, the second doping gas source and H2 is 1:0.09:0.3:150~1:0.13:0.6:250, the gas pressure is 5 Torr~7 Torr, the starting power is 10000 W~15000 W, and the starting time is 80 s~120 s.

[0109] In the step of preparing the seventh doped sublayer, the preparation parameters include: the process gas includes SiH4, N2O, a second doping gas source and H2, and the flow ratio of SiH4, N2O, the second doping gas source and H2 is 1:0.1:0.4:100~1:0.14:0.8:200, the gas pressure is 5 Torr~7 Torr, the starting power is 10000 W~15000 W, and the starting time is 80 s~120 s.

[0110] By controlling the preparation parameters within the above range, it helps to ensure that the prepared film layer has high quality and has a good contact effect with the second passivation layer, thereby ensuring the mobility of carriers in the third doped silicon layer.

[0111] 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, wherein the mixed gas source includes B2H6 and H2, and the volume ratio of B2H6 to H2 is 2%.

[0112] 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 to seventh doping sublayers is 0.4%~1.6%, wherein the doping ratio = mixed gas source × 2% ÷ SiH4, and the mixed gas source and SiH4 both refer to the flow rate of the introduced gas.

[0113] Furthermore, a second doped silicon layer is provided on the backlight surface of the silicon substrate, and after the step of preparing the first transparent conductive layer on the dielectric layer and the first doped silicon layer, the method for preparing the 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.

[0114] The first electrode and the second electrode are silver electrodes and / or copper electrodes. When they are silver electrodes, they can be prepared by screen printing; when they are copper electrodes, they can be prepared by electroplating.

[0115] 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.

[0116] The technical solution of the present application will be further explained below in conjunction with more specific embodiments and experimental test results.

[0117] Embodiment 1: The N-type silicon substrate is textured.

[0118] Prepare the second passivation layer on the backlit side of the silicon substrate: The fifth passivation sublayer is prepared, the process gas includes SiH4, and the SiH4 flow rate is 1900 sccm, the gas pressure is 0.6 Torr, the ignition power is 1500 W, and the ignition time is 4 s; The sixth passivation sublayer is prepared, the process gas includes SiH4, and the SiH4 flow rate is 1900 sccm, the gas pressure is 0.4 Torr, the ignition power is 600 W, and the ignition time is 7 s; The seventh passivation sublayer was prepared, the process gases included SiH4 and H2, and the flow ratio of SiH4 to H2 was 1:2.5, the gas pressure was 0.6 Torr, the ignition power was 400 W, and the ignition time was 35 s; The eighth passivation sublayer was prepared, the process gases included SiH4 and H2, the flow ratio of SiH4 to H2 was 1:10, the gas pressure was 0.6 Torr, the ignition power was 3500 W, and the ignition time was 10 s.

[0119] The 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: The first passivation sublayer was prepared, the process gas included SiH4 and N2O, the flow ratio of SiH4 to N2O was 1:0.08, the gas pressure was 0.6 Torr, the ignition power was 1500 W, and the ignition time was 3 s; The second passivation sublayer is prepared, the process gas includes SiH4, and the SiH4 flow rate is 1900 sccm, the gas pressure is 0.6 Torr, the ignition power is 600 W, and the ignition time is 3 s; The third passivation sublayer was prepared, the process gases included SiH4 and H2, and the flow ratio of SiH4 to H2 was 1:2.5, the gas pressure was 0.6 Torr, the ignition power was 800 W, and the ignition time was 29 s; The fourth passivation sublayer was prepared, the process gases included SiH4 and H2, the flow ratio of SiH4 to H2 was 1:10, the gas pressure was 0.6 Torr, the ignition power was 4000 W, and the ignition time was 10 s.

[0120] The mask is placed on the first passivation layer, and a patterned first doped silicon layer is prepared on the first passivation layer using the mask, wherein 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 : The first doped sublayer was prepared, the process gas included SiH4, N2O and H2, and the flow ratio of SiH4, N2O and H2 was 1:4:300, the gas pressure was 5 Torr, the ignition power was 7000 W, and the ignition time was 6 s; The second doped sublayer was prepared, the process gas included SiH4, N2O, PH3 and H2, and the flow ratio of SiH4, N2O, PH3 and H2 was 1:1:8:200, the gas pressure was 5 Torr, the ignition power was 10000 W, and the ignition time was 40 s; In the step of preparing the third doped sublayer, the process gas includes SiH4, N2O, PH3 and H2, and the flow ratio of SiH4, N2O, PH3 and H2 is 1:1:10:200, the gas pressure is 5 Torr, the ignition power is 10000 W, and the ignition time is 120 s; In the step of preparing the oxygen-free contact layer, the process gas includes SiH4, PH3 and H2, and the flow ratio of SiH4, PH3 and H2 is 1:12:200, the gas pressure is 5 Torr, the ignition power is 10000 W, and the ignition time is 30 s.

[0121] The mask was replaced and a dielectric layer was prepared on the first passivation layer. The material of the dielectric layer was hydrogenated silicon oxide. The process gases included SiH4, N2O and H2, and the flow ratio of SiH4, N2O and H2 was 1:2:50. The starting power was 1000 W, the starting time was 15 s, the thickness of the second doped silicon layer was 1.5 nm, and the refractive index of the dielectric layer was 2.0.

[0122] Preparing a second doped silicon layer on the second passivation layer: The fourth doped sublayer was prepared, the process gas included SiH4, N2O, the second doping gas source and H2, and the flow ratio of SiH4, N2O, the second doping gas source and H2 was 1:0.14:0.7:300, the gas pressure was 6 Torr, the ignition power was 9000 W, and the ignition time was 6 s; The fifth doped sublayer was prepared, the process gas included SiH4, N2O, B2H6 and H2, and the flow ratio of SiH4, N2O, B2H6 and H2 was 1:0.1:0.3:250, the gas pressure was 6 Torr, the ignition power was 12000 W, and the ignition time was 80 s; The sixth doped sublayer was prepared, the process gas included SiH4, N2O, B2H6 and H2, and the flow ratio of SiH4, N2O, B2H6 and H2 was 1:0.1:0.4:180, the gas pressure was 6 Torr, the ignition power was 12000 W, and the ignition time was 100 s; The seventh doped sublayer was prepared, and the process gases included SiH4, N2O, B2H6 and H2, and the flow ratio of SiH4, N2O, B2H6 and H2 was 1:0.13:0.6:150, the gas pressure was 6 Torr, the ignition power was 12000 W, and the ignition time was 100 s.

[0123] A first transparent conductive layer is prepared on the first doped silicon layer and the dielectric layer, and the refractive index of the first transparent conductive layer is 1.9.

[0124] preparing a second transparent conductive layer on the third doped silicon layer; Preparing a first electrode on the first transparent conductive layer, wherein the first electrode has a width of 30 μm and a height of 15 μm; A second electrode is formed on the second transparent conductive layer.

[0125] Embodiment 2: The difference between this embodiment and the first embodiment is that the doping concentration of the first doped silicon layer is 1×10 20 atoms / cm 3 .

[0126] Embodiment three: The difference between this embodiment and the first embodiment is that the doping concentration of the first doped silicon layer is 1×10 19 atoms / cm 3 .

[0127] Embodiment 4: The only difference between this embodiment and the first embodiment is that the material of the dielectric layer is silicon nitride.

[0128] Embodiment five: The only difference between this embodiment and the first embodiment is 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.

[0129] Embodiment six: The only difference between this embodiment and the first embodiment is that the width of the first doped silicon layer is 60 μm.

[0130] Comparative Example 1: The only difference between this comparative example and the first embodiment is that the first doped silicon layer is disposed on the first passivation layer as a whole layer, is not a patterned first doped silicon layer, and no dielectric layer is disposed.

[0131] Comparative Example 2: The only difference between this comparative example and the first embodiment is that no dielectric layer is provided, and the first transparent conductive layer is directly provided on the first passivation layer not covered by the patterned first doped silicon layer.

[0132] Performance Testing The following related tests were performed on the solar cells prepared in Examples 1 to 7 and Comparative Examples 1 to 2: This application uses a GIV-60 tester manufactured by Zhongsen Electric Technology Co., Ltd. to test the open circuit voltage, short circuit current, fill factor and other aspects of a solar cell. The silicon wafer of the tested solar cell is 210 mm × 105 mm in size, and the calibrated light intensity is 1000 ± 5 W / m². The experimental test results are as follows.

[0133] Table 1 Performance test results of solar cells

[0134] Analysis of the data of Example 1 and Comparative Example 1 shows 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 improving the utilization rate of light to a high degree and improving the photoelectric conversion performance of the solar cell.

[0135] Analysis of the data of Example 1 and Comparative Example 2 shows 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 presence of the dielectric layer helps to reduce the damage to the first passivation layer during the preparation of the first transparent conductive layer, thereby ensuring the passivation effect of the first passivation layer to a high degree; in addition, there is charge accumulation at the interface between the dielectric layer and the first doped silicon layer, which increases the intensity of the lateral electric field and improves the lateral transmission capability of carriers.

[0136] The data of Example 1, Example 3, and Example 4 show that the open circuit voltage, fill factor, and photoelectric conversion efficiency of Example 1 and Example 3 are better than those of Example 4. This is because the doping concentration of the first doped silicon layer of Example 1 and Example 3 is both within 1×10 20 atoms / cm 3 ~5×10 21 atoms / cm3 Therefore, when the doping concentration is controlled within the above range, it can not only improve the carrier transmission capacity, 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, and then use the high electric field effect to reduce the recombination of carriers at the interface, thereby improving the performance of the solar cell.

[0137] Analysis of the data of Example 1 and Example 5 shows that the photoelectric conversion performance of Example 1 is better than that of Example 5, indicating that using silicon oxide as the dielectric layer is more helpful in further improving the utilization rate of light than silicon nitride, thereby helping to further improve the performance of solar cells.

[0138] Analysis of the data of Example 1 and Example 6 shows that the photoelectric 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 the layers, thereby helping to further improve the utilization rate of sunlight and further improve the performance of solar cells.

[0139] Analysis of the data of Example 1 and Example 7 shows that the photoelectric 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, the carrier transmission performance in the first doped silicon layer can be further guaranteed, and the aggravation of the recombination caused by the high content of the unactivated doping elements can be better avoided, thereby helping to further improve the photoelectric conversion performance of the solar cell.

[0140] The solar cells, preparation methods and photovoltaic modules disclosed in the embodiments of the present application are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the solar cells, preparation methods and photovoltaic modules. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting 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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