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 is provided with a light receiving surface and a backlight surface which are oppositely arranged, and the light receiving surface of the silicon substrate is sequentially provided with a first composite passivation layer, a first doping layer, a first transparent conductive layer and a first electrode; the first composite passivation layer comprises a first intrinsic silicon layer, a first passivation layer, a second passivation layer and a third passivation layer along the direction from the silicon substrate to the first transparent conductive layer; the second passivation layer and the third passivation layer are configured to be prepared through hydrogen and silane, the flow ratio of the hydrogen to the silane for preparing the second passivation layer is A1, the flow ratio of the hydrogen to the silane for preparing the third passivation layer is A2, and A1 and A2 meet the conditions that A1 is larger than or equal to 5 and smaller than or equal to 10: 1, and A2 is larger than or equal to 20 and smaller than or equal to 50: 1. According to the solar cell, the transmission capacity of current carriers can be improved, and the anti-ultraviolet effect of the solar cell can be improved.

Description

Technical Field

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

[0002] Ultraviolet rays have high energy. If solar cells are exposed to ultraviolet light for a long time, not only will the solar cells have more defects and affect the carrier transmission capacity, but it will also cause the material performance of the solar cells to degrade, accelerate the aging rate of the solar cells, and make the structural stability of the solar cells worse. Summary of the invention

[0003] The embodiment of the present invention discloses a solar cell and a preparation method thereof, and a photovoltaic module, so that the solar cell not only has a high anti-ultraviolet effect, but also has a high carrier transmission capacity, thereby improving the structural stability and photoelectric conversion performance of the solar cell.

[0004] In a first aspect, the present application provides a solar cell, the solar cell comprising: a silicon substrate, the silicon substrate having a light-receiving surface and a light-receiving surface disposed opposite to each other, a first composite passivation layer, a first doping layer, a first transparent conductive layer, and a first electrode disposed in sequence on the light-receiving surface of the silicon substrate; Wherein, the first composite passivation layer comprises: a first intrinsic silicon layer, wherein the first intrinsic silicon layer is disposed on the silicon substrate; A first passivation layer, the first passivation layer is disposed on a side of the first intrinsic silicon layer away from the silicon substrate; a second passivation layer, the second passivation layer being disposed on a side of the first passivation layer away from the first intrinsic silicon layer; a third passivation layer, the third passivation layer being disposed on a side of the second passivation layer facing away from the first passivation layer; The second passivation layer and the third passivation layer are configured to be prepared by hydrogen and silane, the flow ratio of the hydrogen and the silane used to prepare the second passivation layer is A1, and the flow ratio of the hydrogen and the silane used to prepare the third passivation layer is A2, and A1 and A2 satisfy: 5:1≤A1≤10:1, 20:1≤A2≤50:1.

[0005] Furthermore, A1 and A2 satisfy: A1:A2=(1:10)~(1:2).

[0006] Further, the first passivation layer is configured to be prepared by the hydrogen and the silane, and a flow ratio of the hydrogen and the silane in the first passivation layer is A3, the A3 is less than the A1, and the A3 satisfies: A3≤5:1.

[0007] Further, the thickness of the first passivation layer is H1, the thickness of the second passivation layer is H2, the thickness of the third passivation layer is H3, and H1, H2 and H3 satisfy: H2>H1, H2>H3.

[0008] Further, H1 satisfies: 0 nm The H2 satisfies: 3 nm≤H2≤5 nm; and / or, The H3 satisfies: 0 nm<H3≤2 nm.

[0009] Furthermore, the crystallization rate of the third passivation layer is 7.5% to 10%, and the crystallization rate of the first doping layer is 10% to 40%.

[0010] Further, the crystallization rate of the first passivation layer is 1% to 5%; and / or, The crystallization rate of the second passivation layer is 5% to 7.5%; and / or, The thickness of the first intrinsic silicon layer is H4, and H4 satisfies: 0 nm<H4≤0.5 nm.

[0011] Furthermore, a second composite passivation layer, a second doping layer, a second transparent conductive layer, and a second electrode are sequentially arranged on the backlight surface of the silicon substrate; Wherein, the second composite passivation layer comprises: a second intrinsic silicon layer, wherein the second intrinsic silicon layer is disposed on the silicon substrate; a fourth passivation layer, the fourth passivation layer being disposed on a side of the second intrinsic silicon layer facing away from the silicon substrate; The fourth passivation layer is configured to be prepared by the hydrogen and the silane, and a flow ratio of the hydrogen and the silane used to prepare the fourth passivation layer is A4, and the A4 satisfies: 40:1≤A4≤70:1.

[0012] Furthermore, the second composite passivation layer further comprises: a fifth passivation layer, the fifth passivation layer being disposed on a surface of the fourth passivation layer facing away from the silicon substrate; a sixth passivation layer, the sixth passivation layer being disposed on a surface of the fifth passivation layer facing away from the silicon substrate; ​The fifth passivation layer and the sixth passivation layer are configured to be prepared by the hydrogen and the silane, the flow ratio of the hydrogen and the silane used to prepare the fifth passivation layer is A5, and the flow ratio of the hydrogen and the silane used to prepare the sixth passivation layer is A6, and the A4, the A5 and the A6 show a downward trend, and the A5 and the A6 satisfy: 30:1≤A5≤60:1, 25:1≤A6≤55:1.

[0013] Further, the thickness of the fourth passivation layer is H5, the thickness of the fifth passivation layer is H6, the thickness of the sixth passivation layer is H7, and H5, H6 and H7 satisfy: H6>H5, H6>H7.

[0014] Further, H5 satisfies: 0 nm<H5≤1 nm; and / or, The H6 satisfies: 3 nm≤H6≤5 nm; and / or, The H7 satisfies: 0 nm<H7≤1.5 nm.

[0015] Further, the thickness of the second intrinsic silicon layer is H8, and H8 satisfies: 0 nm<H8≤0.5 nm; and / or, The thickness of the sixth passivation layer is smaller than the thickness of the third passivation layer.

[0016] In a second aspect, the present application discloses a method for preparing a solar cell, the method comprising the following steps: A first intrinsic silicon layer is prepared on a light-receiving surface of a silicon substrate, a first passivation layer is prepared on the first intrinsic silicon layer, a second passivation layer is prepared on the first passivation layer by hydrogen and silane, and a third passivation layer is prepared on the second passivation layer by hydrogen and silane to obtain a first composite passivation layer; wherein the flow ratio of the hydrogen and the silane used to prepare the second passivation layer is A1, and the flow ratio of the hydrogen and the silane used to prepare the third passivation layer is A2, and A1 and A2 satisfy: 5:1≤A1≤10:1, 20:1≤A2≤50:1; preparing a first doping layer on the third passivation layer; preparing a first transparent conductive layer on the first doped layer; A first electrode is prepared on the first transparent conductive layer to obtain the solar cell.

[0017] Furthermore, in the step of preparing the first intrinsic silicon layer on the light-receiving surface of the silicon substrate, the preparation parameters include: the process gas includes SiH 4, gas pressure is 0.6 Torr~0.97 Torr, starting power is 800 W~1200 W, starting time is 1 s~2 s, starting time is 1 s~2 s, SiH 4 The flow rate is 800 sccm~1800 sccm; and / or, In the step of preparing the second passivation layer on the first passivation layer by using hydrogen and silane, the process gas includes SiH 4 and H 2 , gas pressure is 0.5 Torr~0.57 Torr, ignition power is 600 W~800 W, ignition time is 15 s~25 s, SiH 4 The flow rate is 600 sccm~1200 sccm, H 2 The flow rate is 3000 sccm~12000 sccm; and / or, In the step of preparing a third passivation layer on the second passivation layer by using the hydrogen and the silane, the preparation parameters include: the process gas includes SiH 4 and H 2 , gas pressure is 0.5 Torr~0.57 Torr, ignition power is 600 W~800 W, ignition time is 10 s~15 s, SiH 4 The flow rate is 600 sccm~1200 sccm, H 2 The flow rate is 12000 sccm~60000 sccm.

[0018] Further, the step of preparing a first passivation layer on the first intrinsic silicon layer includes: preparing a first passivation layer on the first intrinsic silicon layer by using the hydrogen and the silane, wherein the flow ratio of the hydrogen and the silane in the first passivation layer is A3, and A3 is less than A1, and A3 satisfies: A3≤5:1.

[0019] Further, the preparation parameters include: the process gas includes SiH 4 and H 2 , gas pressure is 0.5 Torr~0.57 Torr, ignition power is 400 W~600 W, ignition time is 2 s~4 s, SiH 4 The flow rate is 200 sccm~600 sccm, H 2 The flow rate is 200 sccm~3000 sccm.

[0020] Furthermore, after the step of preparing the first composite passivation layer and before the step of preparing the first doping layer on the third passivation layer, the method for preparing a solar cell also includes: preparing a second intrinsic silicon layer on the backlight side of the silicon substrate, and preparing a fourth passivation layer on the surface of the second intrinsic silicon layer facing away from the silicon substrate by using the hydrogen and the silane to prepare a second composite passivation layer; wherein the flow ratio of the hydrogen and the silane used to prepare the fourth passivation layer is A4, and A4 satisfies: 40:1≤A4≤70:1.

[0021] Furthermore, in the step of preparing the second intrinsic silicon layer on the backlight surface of the silicon substrate, the preparation parameters include: the process gas includes SiH 4 , gas pressure is 0.7 Torr~0.97 Torr, ignition power is 800 W~1200 W, ignition time is 1 s~2 s, SiH 4 The flow rate is 800 sccm~1800 sccm; and / or, In the step of preparing a fourth passivation layer on a surface of the second intrinsic silicon layer facing away from the silicon substrate by using the hydrogen and the silane, the preparation parameters include: the process gas includes SiH 4 and H 2 , gas pressure is 0.5 Torr~0.57 Torr, ignition power is 400 W~600 W, ignition time is 2 s~4 s, SiH 4 The flow rate is 200 sccm~600 sccm, H 2 The flow rate is 8000 sccm~42000 sccm.

[0022] Furthermore, after the step of preparing a fourth passivation layer on the surface of the second intrinsic silicon layer facing away from the silicon substrate by using the hydrogen and the silane, and before the step of preparing a first doped layer on the third passivation layer, the method for preparing a solar cell also includes: sequentially preparing a fifth passivation layer and a sixth passivation layer on the surface of the fourth passivation layer facing away from the silicon substrate by using the hydrogen and the silane, wherein the flow ratio of the hydrogen and the silane for preparing the fifth passivation layer is A5, and the flow ratio of the hydrogen and the silane for preparing the sixth passivation layer is A6, and A4, A5 and A6 show a downward trend, and A5 and A6 satisfy: 30:1≤A5≤60:1, 25:1≤A6≤55:1.

[0023] Furthermore, in the step of preparing the fifth passivation layer, the preparation parameters include: the process gas includes SiH 4 and H 2, gas pressure is 0.5 Torr~0.57 Torr, ignition power is 600 W~800 W, ignition time is 15 s~25 s, SiH 4 The flow rate is 600 sccm~1200 sccm, H 2 The flow rate is 18000 sccm~72000 sccm; and / or, In the step of preparing the sixth passivation layer, the preparation parameters include: the process gas includes SiH 4 and H 2 , gas pressure is 0.5 Torr~0.57 Torr, ignition power is 800 W~1000 W, ignition time is 5 s~10 s, SiH 4 The flow rate is 600 sccm~1200 sccm, H 2 The flow rate is 15000 sccm~66000 sccm.

[0024] Further, after the step of preparing the first doping layer on the third passivation layer and before the step of preparing the first transparent conductive layer on the first doping layer, the method for preparing the solar cell includes: preparing a second doping layer on the second composite passivation layer; After the step of preparing a first transparent conductive layer on the first doped layer and before the step of preparing a first electrode on the first transparent conductive layer, the method for preparing a solar cell includes: preparing a second transparent conductive layer on the second doped layer; After the step of preparing the first electrode on the first transparent conductive layer, the method for preparing the solar cell includes: preparing the second electrode on the second transparent conductive layer.

[0025] In a third aspect, an embodiment of the present application discloses a photovoltaic module, comprising the solar cell described in the first aspect, or the solar cell prepared by any preparation method described in the second aspect.

[0026] 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. A first composite passivation layer is arranged on a light-receiving surface and the first composite passivation layer includes a first intrinsic silicon layer and a first passivation layer, a second passivation layer, and a third passivation layer arranged on the first intrinsic silicon layer. The flow ratio of hydrogen and silane in the second passivation layer and the third passivation layer is regulated so that the synergy between the layers is high. Therefore, the first composite passivation layer can not only improve the carrier transmission capacity, but also increase the content of Si-H bonds in the first composite passivation layer, thereby improving the anti-ultraviolet effect of the solar cell.

[0027] The present application helps to suppress the epitaxial growth of the silicon substrate by setting a first intrinsic silicon layer. And in order to avoid the problems of powder loss and carrier recombination caused by setting a first intrinsic silicon layer. The present application further sets a first passivation layer on the first intrinsic silicon layer, and the first passivation layer can react with the unreacted groups in the first intrinsic silicon layer to avoid powder loss; and a second passivation layer is set on the first passivation layer of the present application, and by A1 in the second passivation layer being within the above range, the hydrogen in the second passivation layer can diffuse into the first passivation layer and the first intrinsic silicon layer, and combine with defects such as dangling bonds in the first passivation layer and the first intrinsic silicon layer, thereby reducing the recombination of carriers and improving the carrier transmission capacity.

[0028] In addition, by setting A1 and A2 within the above range, the second passivation layer and the third passivation layer have a higher matching effect. First, the second passivation layer and the third passivation layer can provide more hydrogen to combine with silicon, which can effectively ensure the Si-H bond content in the first composite passivation layer after ultraviolet light irradiation, so that the second passivation layer and the third passivation layer have a higher anti-ultraviolet effect; secondly, the above range makes hydrogen mainly exist in the form of Si-H bonds, reducing the existence of free hydrogen, thereby avoiding the existence of hydrogen defects caused by excessive hydrogen; finally, by setting A1 and A2 within the above range, the electric field between the second passivation layer and the third passivation layer has a higher matching degree, thereby providing a channel that is more conducive to carrier transmission, avoiding the recombination of carriers at the interface caused by electric field mutations, thereby helping to improve the performance of solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] 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.

[0030] Figure 1 is a schematic diagram of the structure of a solar cell provided in an embodiment of the present application (showing an enlarged view of the first composite passivation layer on the light-receiving surface); Figure 2 It is a schematic diagram of the structure of a solar cell provided in an embodiment of the present application (showing an enlarged view of the second composite passivation layer on the backlight side).

[0031] Icon: 1. Silicon substrate; 1a. Light-receiving surface; 1b. Backlight surface; 2. First composite passivation layer; 21. First intrinsic silicon layer; 22. First passivation layer; 23. Second passivation layer; 24. Third passivation layer; 3. First doped layer; 4. First transparent conductive layer; 5. First electrode; 6. Second composite passivation layer; 61. Second intrinsic silicon layer; 62. Fourth passivation layer; 63. Fifth passivation layer; 64. Sixth passivation layer; 7. Second doped layer; 8. Second transparent conductive layer; 9. Second electrode. DETAILED DESCRIPTION

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] The technical solution provided by the present invention will be further described below in conjunction with embodiments and drawings.

[0037] Solar cells are highly sensitive to ultraviolet rays. When solar cells are exposed to ultraviolet rays for a long time, it is easy to cause the Si-H bonds in the solar cells to break, produce more free hydrogen, lead to the existence of hydrogen defects, increase the probability of carrier recombination, and then cause the performance of solar cells to deteriorate seriously. In addition, ultraviolet light exposure will also accelerate the aging of solar cell materials and other problems, thus causing serious degradation of solar cell material performance and having a great impact on the long-term stability of solar cells.

[0038] In addition, in addition to being affected by ultraviolet light, the silicon substrate of the solar cell material will also have the problem of epitaxial growth. On the one hand, the existence of this epitaxial growth makes the crystal structure of the silicon substrate and the epitaxial layer mismatch, resulting in more defects at the interface and aggravated carrier recombination; on the other hand, certain impurity elements in the epitaxial layer will diffuse into the silicon substrate, causing the crystal structure of the silicon substrate to change, so that the material of the solar cell is seriously attenuated, affecting the long-term stability and photoelectric conversion performance of the solar cell.

[0039] Based on the above analysis, the embodiments of the present application provide a solar cell and a preparation method thereof, and a photovoltaic module. The solar cell can not only effectively improve the carrier transmission capacity, but also effectively improve the anti-ultraviolet effect of the solar cell, so as to promote the extension of the service life of the solar cell and optimize its photoelectric conversion efficiency.

[0040] In a first aspect, the present application provides a solar cell, such as Figure 1 As shown, the solar cell includes: a silicon substrate 1, the silicon substrate 1 has a light-receiving surface 1a and a backlight surface 1b arranged opposite to each other, and a first composite passivation layer 2, a first doping layer 3, a first transparent conductive layer 4, and a first electrode 5 are sequentially arranged on the light-receiving surface 1a of the silicon substrate 1.

[0041] Wherein, the first composite passivation layer 2 comprises: A first intrinsic silicon layer 21, wherein the first intrinsic silicon layer 21 is disposed on the silicon substrate 1; A first passivation layer 22, the first passivation layer 22 is disposed on a side of the first intrinsic silicon layer 21 away from the silicon substrate 1; A second passivation layer 23, the second passivation layer 23 is disposed on a side of the first passivation layer 22 away from the first intrinsic silicon layer 21; A third passivation layer 24, the third passivation layer 24 is disposed between the second passivation layers 23 and on a side away from the first intrinsic silicon layer 21; The second passivation layer 23 and the third passivation layer 24 are configured to be prepared by hydrogen and silane. The flow ratio of hydrogen and silane used to prepare the second passivation layer 23 is A1, and the flow ratio of hydrogen and silane used to prepare the third passivation layer 24 is A2. A1 and A2 satisfy: 5:1≤A1≤10:1, 20:1≤A2≤50:1.

[0042] The present application sets a first composite passivation layer 2 on the light-receiving surface of the silicon substrate and utilizes the mutual cooperation between the composite film layers in the first composite passivation layer 2, which helps to improve the anti-ultraviolet effect of the solar cell while improving the carrier transmission capacity, thereby greatly improving the photoelectric conversion performance and service life of the solar cell.

[0043] Among them, the present application suppresses the generation of an epitaxial layer on the silicon substrate 1 by setting a first intrinsic silicon layer 21, that is, the first intrinsic silicon layer 21 is used to prevent the epitaxial growth of the silicon substrate 1. However, the applicant found that there are some unreacted groups in the first intrinsic silicon layer 21, and the presence of these unreacted groups will cause powder loss; and the first intrinsic silicon layer 21 still has certain defects, resulting in carrier recombination in the first intrinsic silicon layer 21.

[0044] Therefore, in order to reduce the powder loss and carrier recombination aggravation phenomenon in the first intrinsic silicon layer 21, the present application sets a first passivation layer 22 on the first intrinsic silicon layer 21, and the first passivation layer 22 can combine with the unreacted groups in the first intrinsic silicon layer 21, thereby reducing the powder loss phenomenon of the first intrinsic silicon layer 21; in addition, since a second passivation layer 23 is set on the first passivation layer 22, the value of A1 of the second passivation layer 23 is controlled so that the hydrogen in the second passivation layer 23 can enter the first passivation layer 22 and the first intrinsic silicon layer 21, passivate the defects in the first passivation layer 22 and the first intrinsic silicon layer 21, reduce the recombination of carriers in the first passivation layer 22 and the first intrinsic silicon layer 21, and improve the carrier transmission capacity.

[0045] In addition, by setting A1 and A2 within the above range, the second passivation layer 23 and the third passivation layer 24 have a higher matching effect. First, when ultraviolet rays are irradiated from the light-receiving surface, when they irradiate the first composite passivation layer, they first act on the third passivation layer 24, which easily leads to the breaking of the Si-H bond in the third passivation layer 24. The present application controls A2 in the third passivation layer 24 within the above range, so that the third passivation layer 24 can provide sufficient hydrogen to combine with silicon, thereby ensuring the content of Si-H bonds in the third passivation layer 24; at the same time, part of the ultraviolet light will pass through the third passivation layer 24 and enter the second passivation layer 23, so by controlling A1 in the second passivation layer 23 within the above range, the second passivation layer 23 can provide sufficient hydrogen to combine with silicon, thereby ensuring the content of Si-H bonds in the second passivation layer 23, that is, the present application controls A1 and A2 in the first composite passivation layer 2 within the above range, so that the solar cell has a higher anti-ultraviolet effect. Secondly, the above range allows hydrogen to exist mainly in the form of Si-H bonds, reducing the presence of free hydrogen, thereby avoiding the presence of hydrogen defects caused by excessive hydrogen, thereby helping to ensure the carrier transmission capacity. Finally, by setting A1 and A2 within the above range, the electric field between the second passivation layer 23 and the third passivation layer 24 has a higher matching degree, thereby providing a channel that is more conducive to carrier transmission, avoiding the recombination and aggregation of carriers at the interface of the second passivation layer 23 and the third passivation layer 24 due to the sudden change of the electric field, improving the carrier transmission capacity, and thus helping to improve the performance of the solar cell.

[0046] In addition, since the second passivation layer 23 is located between the first passivation layer 22 and the third passivation layer 24, the second passivation layer 23 does not need to consider the phenomenon of powdering of the first intrinsic silicon layer 21, nor does it need to consider the matching with the first doping layer 3, so the third passivation layer 24 can effectively exert its passivation effect, thereby being used as the main passivation layer in the first composite passivation layer 2. By controlling A2 within the above range, it is helpful to further reduce defects in the third passivation layer 24 and improve the passivation effect of the third passivation layer 24.

[0047] Illustratively, A1 is 5:1, 7:1, 10:1, etc.; A2 is 20:1, 30:1, 50:1, etc.

[0048] The transparent conductive oxide 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; the doped layer includes at least one of a doped microcrystalline silicon layer, a doped polycrystalline silicon layer, and a doped amorphous silicon layer.

[0049] Furthermore, A1 and A2 satisfy: A1:A2=(1:10)~(1:2). When A1:A2 is within the above range, it helps to further improve the synergy between the second passivation layer 23 and the third passivation layer 24, making the electric field transition uniform, which helps to improve the performance of the solar cell.

[0050] Further, the first passivation layer 22 is configured to be prepared by hydrogen and silane, and the flow ratio of hydrogen to silane in the first passivation layer 22 is A3, A3 is less than A1, and A3 satisfies: A3≤5:1.

[0051] By further controlling the flow ratio of hydrogen and silane in the first passivation layer 22, the matching degree of the interfaces of each layer is made higher and the uniformity of the electric field transition is made higher, which helps to reduce the recombination of carriers at the interface and further improve the carrier transmission capacity.

[0052] In addition, when the first passivation layer 22 contains hydrogen, it is more helpful to reduce the defects of the first composite passivation layer 2 and further improve the carrier transmission capacity. Moreover, through the synergistic effect of the three passivation layers, it is also helpful to further improve the anti-ultraviolet effect. Specifically, ultraviolet light will penetrate the third passivation layer 24 and enter the second passivation layer 23 and the first passivation layer 22 in sequence. Therefore, the present application controls the contents of A1, A2, and A3 within the above range to ensure that each passivation layer contains sufficient hydrogen to combine with silicon to a high degree, which helps to further improve the anti-ultraviolet effect of the solar cell, thereby reducing the negative impact of ultraviolet rays on the solar cell.

[0053] Exemplarily, A3 is 1:1, 3:1, 5:1, etc.

[0054] The thickness of the first passivation layer 22 is H1, the thickness of the second passivation layer 23 is H2, and the thickness of the third passivation layer 24 is H3, H2>H1, H2>H3.

[0055] When the thickness relationship satisfies the above range, since the second passivation layer 23 serves as the main passivation layer, the passivation effect of the first composite passivation layer 2 is effectively ensured by setting the second passivation layer 23 to be thicker.

[0056] Among them, H1 satisfies: 0 nm

[0057] Among them, for the first passivation layer 22, when the thickness of the first passivation layer 22 is within the above-mentioned range, it can effectively act on the first intrinsic silicon layer 21, which can not only reduce the powdering phenomenon of the first intrinsic silicon layer 21 to a large extent, but also help to further reduce the series resistance of the first passivation layer 22; for the third passivation layer 24, at this thickness, the contact performance with the first doped layer 3 is better, which helps to better transmit carriers at the interface.

[0058] In addition, the thickness of the film layer mentioned in the present application refers to the average thickness of the film layer. Taking the thickness of the first passivation layer 22 as an example, it is a value obtained by calculating the thickness values ​​measured at multiple positions of the first passivation layer 22, which reflects the overall thickness level of the first passivation layer 22 in the thickness direction.

[0059] For example, an ellipsometer can be used to test the thickness of the first passivation layer 22. Taking the measurement of the thickness of the first passivation layer 22 as an example, at least five points can be taken on the first passivation layer 22, and the thickness values ​​of the five points can be measured by an ellipsometer, and then the average value of the thickness values ​​of the five points can be calculated to obtain the thickness of the first passivation layer 22. Among them, the ellipsometer can be an ellipsometer manufactured by the German company sentch, model SE-800. This application does not limit the thickness test instrument and specific method, as long as the purpose of this application can be achieved.

[0060] Furthermore, the crystallization rate of the third passivation layer 24 is 7.5% to 10%, and the crystallization rate of the first doping layer 3 is 10% to 40%.

[0061] When the crystallization rate of the third passivation layer 24 and the first doping layer 3 is within the above range, the crystal matching between the third passivation layer 24 and the first doping layer 3 is higher, and the work function matching is higher, which helps to improve the performance of the solar cell to a high degree. Exemplarily, the crystallization rate of the third passivation layer 24 is 7.5%, 8%, 9%, 10%, etc.; the crystallization rate of the first doping layer 3 is 10%, 20%, 30%, 40%, etc.

[0062] ​Furthermore, the crystallization rate of the first passivation layer 22 is 1% to 5%; the crystallization rate of the second passivation layer 23 is 5% to 7.5%. When the crystallization rates of the first passivation layer 22 and the second passivation layer 23 are within the above range, it is helpful to improve the matching degree between the first passivation layer 22, the second passivation layer 23 and the third passivation layer 24 to a high degree, and further reduce the recombination of carriers at the interface.

[0063] Exemplarily, the crystallization rate of the first passivation layer 22 is 1%, 3%, 5%, etc.; the crystallization rate of the second passivation layer 23 is 5%, 6%, 7.5%, etc.

[0064] Further, the thickness of the first intrinsic silicon layer 21 is H4, and H4 satisfies: 0 nm<H4≤0.5 nm; when the thickness of H4 is within the above range, it helps to provide a higher anti-epitaxial effect and improve the performance of the solar cell. Exemplarily, the thickness of H4 is 0.1 nm, 0.3 nm, 0.5 nm, etc.

[0065] Furthermore, if Figure 2 As shown, a second composite passivation layer 6, a second doping layer 7, a second transparent conductive layer 8, and a second electrode 9 are sequentially arranged on the backlight surface 1b of the silicon substrate 1.

[0066] Wherein, the second composite passivation layer 6 comprises: A second intrinsic silicon layer 61, wherein the second intrinsic silicon layer 61 is disposed on the silicon substrate 1; A fourth passivation layer 62, which is disposed on a side of the second intrinsic silicon layer 61 facing away from the silicon substrate 1; The fourth passivation layer 62 is configured to be prepared by hydrogen and silane, and the flow ratio of hydrogen and silane used to prepare the fourth passivation layer 62 is A4, and A4 satisfies: 40:1≤A4≤70:1.

[0067] The present application sets a second intrinsic silicon layer 61 on the backlight surface 1b of the silicon substrate 1. The existence of the second intrinsic silicon layer 61 can prevent the epitaxial growth of the silicon substrate 1. The fourth passivation layer 62 is further set on the second intrinsic silicon layer 61. The fourth passivation layer 62 can combine with the unreacted groups in the second intrinsic silicon layer 61, thereby avoiding the phenomenon of powder falling and ensuring the effect of the second intrinsic silicon layer 61. In addition, the present application sets A4 within the above range so that part of the hydrogen diffuses into the second intrinsic silicon layer 61. The hydrogen diffused into the second intrinsic silicon layer 61 can passivate the defects inside the second intrinsic silicon layer 61 and can contact the silicon substrate 1, thereby helping to passivate the silicon substrate 1 and improving the passivation effect of the backlight surface 1b of the solar cell.

[0068] According to the above records, the present application helps to ensure the anti-ultraviolet effect of the solar cell to a high degree by controlling A1 of the second passivation layer 23 of the light-receiving surface and A4 in the third passivation layer; but the above-mentioned setting of the light-receiving surface 1a may cause the passivation effect of the light-receiving surface 1a to be affected. Therefore, the present application helps to improve the passivation effect of the backlight surface 1b by further controlling A4 in the fourth passivation layer of the backlight surface 1b, thereby improving the overall performance of the solar cell. That is, the solar cell provided by the present application has improved the performance of both the light-receiving surface 1a and the backlight surface 1b, which not only optimizes the anti-ultraviolet effect of the light-receiving surface 1a and ensures the long-term stability of the solar cell material; it also improves the passivation effect of the backlight surface 1b and reduces the recombination of carriers, thereby improving the performance of the solar cell to a high degree.

[0069] The doping types of the first doping layer 3 and the second doping layer 7 are opposite, that is, one of the first doping layer 3 and the second doping layer 7 is an N-type doping layer and the other is a P-type doping layer.

[0070] For further information, see Figure 2 , the second composite passivation layer 6 further includes: A fifth passivation layer 63, the fifth passivation layer 63 is disposed on a surface of the fourth passivation layer 62 that is away from the silicon substrate 1; A sixth passivation layer 64, which is disposed on a surface of the fifth passivation layer 63 that is away from the silicon substrate 1; The fifth passivation layer 63 and the sixth passivation layer 64 are configured to be prepared by hydrogen and silane. The flow ratio of hydrogen and silane used to prepare the fifth passivation layer 63 is A5, and the flow ratio of hydrogen and silane used to prepare the sixth passivation layer 64 is A6. A4, A5, and A6 show a downward trend, and A5 and A6 satisfy: 30:1≤A5≤60:1, 25:1≤A6≤55:1.

[0071] The present application further arranges a fifth passivation layer 63 and a sixth passivation layer 64 on the fourth passivation layer 62, wherein, since the fifth passivation layer 63 is located between the sixth passivation layer 64 and the fourth passivation layer 62, the fifth passivation layer 63 does not need to consider how to avoid the yellow powder falling phenomenon of the second intrinsic silicon layer 61, nor does it need to consider the contact with the second doping layer 7, so the fifth passivation layer 63 can effectively exert its passivation effect, thereby being used as the main passivation layer in the second composite passivation layer 6, ensuring the passivation effect of the second composite passivation layer 6. And by controlling the flow ratio within the above range, the fourth passivation layer 62, the fifth passivation layer 63 and the sixth passivation layer 64 have a higher synergistic effect, which helps to further increase the passivation effect of the backlight surface 1b and improve the photoelectric conversion efficiency of the solar cell. Exemplarily, A5 is 30:1, 55:1, 60:1, etc.; A6 is 25:1, 45:1, 55:1, etc.

[0072] Further, the thickness of the fourth passivation layer 62 is H5, the thickness of the fifth passivation layer 63 is H6, and the thickness of the sixth passivation layer 64 is H7, and H5, H6 and H7 satisfy: H6>H5, H6>H7.

[0073] In addition, since the fifth passivation layer 63 serves as the main passivation layer of the second composite passivation layer 6 , providing the fifth passivation layer 63 with a relatively high thickness can help to further improve the passivation effect of the second composite passivation layer 6 .

[0074] Among them, H5 satisfies: 0 nm<H5≤1 nm; H6 satisfies: 3 nm≤H6≤5 nm; H7 satisfies: 0 nm<H7≤1.5 nm. When the thickness is within the above range, the fourth passivation layer 62 and the fifth passivation layer 63 and the sixth passivation layer 64 have a higher match and a better synergistic effect, which helps to better improve the performance of the solar cell. Exemplarily, the thickness of H5 is 0.1 nm, 0.5 nm, 1 nm, etc.; the thickness of H3 is 3 nm, 4 nm, 5 nm, etc.; the thickness of H6 is 0.1 nm, 1 nm, 1.5 nm, etc.

[0075] Further, the thickness of the second intrinsic silicon layer 61 is H8, and H8 satisfies: 0 nm<H8≤0.5 nm; the thickness of H8 within the above range is helpful to provide a higher anti-epitaxial effect. Exemplarily, H8 is 0.2 nm, 0.4 nm, 0.5 nm, etc.

[0076] Furthermore, the thickness of the sixth passivation layer 64 is less than the thickness of the third passivation layer 24. In the solution of the present application, the third passivation layer 24 is located on the light-receiving surface 1a and is arranged close to the first doping layer 3, and the third passivation layer 24 has high contact performance with the first doping layer 3; while the sixth passivation layer 64 is arranged on the backlight surface 1b and has poor contact performance with the second doping layer 7, so by setting the thickness of the sixth passivation layer 64 to be less than the thickness of the second passivation layer 23, on the one hand, it helps to reduce the poor contact performance between the sixth passivation layer 64 and the second doping layer 7 due to crystal mismatch; on the other hand, the thicker third passivation layer 24 can ensure the anti-ultraviolet effect of the solar cell to a higher degree and improve its contact performance with the first doping layer 3.

[0077] In a second aspect, the present application discloses a method for preparing a solar cell, the method comprising the following steps: A first intrinsic silicon layer is prepared on the light-receiving surface of a silicon substrate, a first passivation layer is prepared on the first intrinsic silicon layer, a second passivation layer is prepared on the first passivation layer by hydrogen and silane, and a third passivation layer is prepared on the second passivation layer by hydrogen and silane to obtain a first composite passivation layer; wherein the flow ratio of hydrogen and silane used to prepare the second passivation layer is A1, and the flow ratio of hydrogen and silane used to prepare the third passivation layer is A2, and A1 and A2 satisfy: 5:1≤A1≤10:1, 20:1≤A2≤50:1; preparing a first doping layer on the third passivation layer; preparing a first transparent conductive layer on the first doped layer; A first electrode is prepared on the first transparent conductive layer to obtain a solar cell.

[0078] In the step of preparing the first intrinsic silicon layer on the light-receiving surface of the silicon substrate, the preparation parameters include: the process gas includes SiH 4 , gas pressure is 0.6 Torr~0.97 Torr, ignition power is 800 W~1200 W, ignition time is 1 s~2s, SiH 4 The flow rate is 800 sccm~1800 sccm.

[0079] In the step of preparing the second passivation layer on the first passivation layer by using hydrogen and silane, the process gas includes SiH 4 and H 2 , gas pressure is 0.5 Torr~0.57 Torr, ignition power is 600 W~800 W, ignition time is 15 s~25 s, SiH 4 The flow rate is 600 sccm~1200 sccm, H 2 The flow rate is 3000 sccm~12000 sccm.

[0080] In the step of preparing the third passivation layer on the second passivation layer by using hydrogen and silane, the preparation parameters include: the process gas includes SiH 4 and H 2 , gas pressure is 0.5 Torr~0.57 Torr, ignition power is 600 W~800 W, ignition time is 10 s~15 s, SiH 4 The flow rate is 600 sccm~1200 sccm, H 2 The flow rate is 12000 sccm~60000sccm.

[0081] In this preparation method, compared with the first passivation layer, the first intrinsic silicon layer has a higher power during preparation, which results in a larger number of unreacted groups and a more serious powder falling phenomenon. Therefore, the first passivation layer is deposited on the first intrinsic silicon layer so that the first passivation layer is combined with the unreacted groups in the first intrinsic silicon layer, thereby avoiding the phenomenon that the unreacted groups turn into yellow powder.

[0082] By controlling the preparation parameters within the above range, the quality of the obtained film layer can be ensured to be high, so that the matching between the layers is good, which helps to improve the performance of the solar cell.

[0083] Furthermore, the step of preparing a first passivation layer on the first intrinsic silicon layer includes: preparing the first passivation layer on the first intrinsic silicon layer by hydrogen and silane, wherein the flow ratio of hydrogen and silane in the first passivation layer is A3, A3 is less than A1, and A3 satisfies: A3≤5:1.

[0084] The preparation parameters include: process gas including SiH 4 and H 2 , gas pressure is 0.5 Torr~0.57 Torr, ignition power is 400 W~600 W, ignition time is 2 s~4 s, SiH 4 The flow rate is 200 sccm~600 sccm, H 2 The flow rate is 200 sccm~3000 sccm.

[0085] By controlling the preparation parameters of the first passivation layer within the above range, the film quality of the first passivation layer is high, which helps to ensure the anti-epitaxial effect of the first passivation layer.

[0086] Furthermore, after the step of preparing the first composite passivation layer and before the step of preparing the first doped layer on the third passivation layer, the method for preparing a solar cell also includes: preparing a second intrinsic silicon layer on the backlight side of the silicon substrate, and preparing a fourth passivation layer on the surface of the second intrinsic silicon layer facing away from the silicon substrate by hydrogen and silane to obtain a second composite passivation layer; wherein the flow ratio of hydrogen and silane used to prepare the fourth passivation layer is A4, and A4 satisfies: 40:1≤A4≤70:1.

[0087] In the step of preparing the second intrinsic silicon layer on the backlight surface of the silicon substrate, the preparation parameters include: the process gas includes SiH 4 , gas pressure is 0.7 Torr~0.97 Torr, ignition power is 800 W~1200 W, ignition time is 1 s~2s, SiH 4 The flow rate is 800 sccm~1800 sccm.

[0088] In the step of preparing a fourth passivation layer on the second intrinsic silicon layer away from the silicon substrate by using hydrogen and silane, the preparation parameters include: the process gas includes SiH 4 and H 2 , gas pressure is 0.5 Torr~0.57 Torr, ignition power is 400 W~600 W, ignition time is 2 s~4 s, SiH 4 The flow rate is 200 sccm~600 sccm, H 2 The flow rate is 8000 sccm~42000 sccm.

[0089] In the preparation method, compared with the fourth passivation layer, the second intrinsic silicon layer has a higher power during preparation, so the number of unreacted groups is larger, so the first passivation layer is deposited on the second intrinsic silicon layer, so that the fourth passivation layer reacts with the unreacted groups in the second intrinsic silicon layer, thereby avoiding the phenomenon that the unreacted groups turn into yellow powder; and by controlling the preparation parameters of the fourth passivation layer within the above range, the passivation effect of the fourth passivation layer is higher, thereby improving the passivation effect of the backlight surface of the solar cell to a greater extent.

[0090] Furthermore, after the step of preparing a fourth passivation layer on the surface of the second intrinsic silicon layer facing away from the silicon substrate by using hydrogen and silane, and before the step of preparing a first doped layer on the third passivation layer, the method for preparing a solar cell also includes: sequentially preparing a fifth passivation layer and a sixth passivation layer on the surface of the fourth passivation layer facing away from the silicon substrate by using hydrogen and silane, wherein the flow ratio of hydrogen and silane used to prepare the fifth passivation layer is A5, and the flow ratio of hydrogen and silane used to prepare the sixth passivation layer is A6, A4, A5, and A6 show a downward trend, and A5 and A6 satisfy: 30:1≤A5≤60:1, 25:1≤A6≤55:1.

[0091] Among them, in the step of preparing the fifth passivation layer, the preparation parameters include: the process gas includes SiH 4 and H 2 , gas pressure is 0.5 Torr~0.57 Torr, ignition power is 600 W~800 W, ignition time is 15 s~25 s, SiH 4 The flow rate is 600 sccm~1200 sccm, H 2 The flow rate is 18000 sccm~72000 sccm.

[0092] In the step of preparing the sixth passivation layer, the preparation parameters include: the process gas includes SiH 4 and H 2 , gas pressure is 0.5 Torr~0.57 Torr, ignition power is 800 W~1000 W, ignition time is 5 s~10 s, SiH4 The flow rate is 600 sccm~1200 sccm, H 2 The flow rate is 15000 sccm~66600 sccm.

[0093] By controlling the preparation parameters within the above range, it helps to ensure that the film quality of the fifth passivation layer and the sixth passivation layer prepared is high, thereby improving the passivation effect of the backlight surface of the solar cell to a high degree.

[0094] Furthermore, after the step of preparing the first doping layer on the third passivation layer and before the step of preparing the first transparent conductive layer on the first doping layer, the method for preparing a solar cell includes: preparing a second doping layer on the second composite passivation layer; After the step of preparing a first transparent conductive layer on the first doped layer and before the step of preparing a first electrode on the first transparent conductive layer, the method for preparing a solar cell includes: preparing a second transparent conductive layer on the second doped layer; After the step of preparing the first electrode on the first transparent conductive layer, the method for preparing the solar cell includes: preparing the second electrode on the second transparent conductive layer.

[0095] In a third aspect, an embodiment of the present application further discloses a photovoltaic module, comprising: the solar cell of the first aspect, or the solar cell prepared by the preparation method of the second aspect.

[0096] The technical solution of the present application will be further explained below in conjunction with more specific embodiments and experimental test results.

[0097] Embodiment 1: The N-type silicon substrate is textured.

[0098] Prepare the first composite passivation layer on the light-receiving surface of the silicon substrate: Preparation of the first intrinsic silicon layer with a thickness of 0.3 nm: the process gas includes SiH 4 , and SiH 4 The flow rate is 1000 sccm, the gas pressure is 0.7 Torr, the ignition power is 900 W, and the ignition time is 1.5 s; Prepare the first passivation layer with a thickness of 0.7 nm and a crystallinity of 4%: the process gas includes SiH 4 and H 2 , gas pressure is 0.55 Torr, ignition power is 500 W, ignition time is 3 s, A3 is 3:1, SiH 4 The flow rate is 500 sccm, H 2 The flow rate is 1500 sccm; Preparation of the second passivation layer with a thickness of 4 nm and a crystallinity of 7%: the process gas includes SiH4 and H 2 , gas pressure is 0.55 Torr, ignition power is 700 W, ignition time is 20 s, A1 is 8:1, SiH 4 The flow rate is 1000 sccm, H 2 The flow rate is 8000 sccm; Preparation of the third passivation layer with a thickness of 1 nm and a crystallinity of 8.5%: the process gas includes SiH 4 and H 2 , gas pressure is 0.55 Torr, ignition power is 700 W, ignition time is 10 s, A2 is 40:1, SiH 4 The flow rate is 1000 sccm, H 2 The flow rate is 40000 sccm.

[0099] Prepare the second composite passivation layer on the backlight side of the silicon substrate: Preparation of a second intrinsic silicon layer with a thickness of 0.3 nm: the process gas includes SiH 4 , gas pressure is 0.85 Torr, ignition power is 1000 W, ignition time is 1.5 s, SiH 4 Flow rate: 1000 sccm; Preparation of the fourth passivation layer with a thickness of 0.5 nm: the process gas includes SiH 4 and H 2 , gas pressure is 0.56 Torr, ignition power is 500 W, ignition time is 3 s, A4 is 60:1, SiH 4 The flow rate is 500 sccm, H 2 The flow rate is 30000sccm; Preparation of a fifth passivation layer with a thickness of 4 nm: the process gases include SiH 4 and H 2 , gas pressure is 0.55 Torr, ignition power is 700 W, ignition time is 20 s, A5 is 45:1, SiH 4 The flow rate is 1000 sccm, H 2 The flow rate is 45000sccm; Preparation of the sixth passivation layer with a thickness of 1 nm: the process gas includes SiH 4 and H 2 , gas pressure is 0.55 Torr, ignition power is 900 W, ignition time is 7 s, A6 is 35:1, SiH 4 The flow rate is 1000 sccm, H 2 The flow rate is 35000 sccm.

[0100] The first doped layer is prepared on the third passivation layer: an N-type doped layer is prepared on the third passivation layer by a PECVD method, the gas pressure is 5 Torr, and the process gas contains SiH 4 , doping gas and H 2 The flow ratio is 1:3:250, the ignition power is 7000W, the ignition time is 175s, and the crystallization rate of the first doping layer is 15%.

[0101] Preparation of the second doped layer on the second composite passivation layer: A P-type doped layer was prepared on the first composite passivation layer by PECVD method, the gas pressure was 5 Torr, and SiH 4 , doping gas and H 2 The flow ratio is 1:3:250, the starting power is 7000W, and the starting time is 175s.

[0102] A first transparent conductive layer is formed on the first doping layer.

[0103] A second transparent conductive layer is formed on the second doping layer.

[0104] A first electrode is formed on the first transparent conductive layer.

[0105] A second electrode is formed on the second transparent conductive layer.

[0106] Embodiment 2: The only difference between this embodiment and the first embodiment is that A3 of the first passivation layer is 8:1.

[0107] Embodiment three: The only difference between this embodiment and the first embodiment is that the second composite passivation layer is a conventional film structure, that is, the film structure includes an intrinsic silicon layer and a passivation layer arranged on the intrinsic silicon layer, and the flow ratio of hydrogen and silane in the passivation layer is 1:1.

[0108] Embodiment 4: The only difference between this embodiment and the first embodiment is that A4 of the fourth passivation layer is 35:1.

[0109] Embodiment five: The only difference between this embodiment and the first embodiment is that A4 of the fourth passivation layer is 75:1.

[0110] Comparative Example 1: The difference between this comparative example and the first embodiment is that the ratio of A1 in the second passivation layer in the first comparative example is 4:1.

[0111] Comparative Example 2: The difference between this comparative example and Example 1 is that the ratio of A1 in the second passivation layer in Comparative Example 1 is 12:1.

[0112] Comparative Example 3: The difference between this comparative example and Example 1 is that A2 in the third passivation layer in Comparative Example 1 is 18:1.

[0113] Comparative Example 4: The difference between this comparative example and Example 1 is that A2 in the third passivation layer in Comparative Example 1 is 52:1.

[0114] Performance Testing The solar cells prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were subjected to the following related tests: 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.

[0115] Table 1 Performance test results of solar cells

[0116] Analysis of the data of Example 1, Comparative Example 1, and Comparative Example 2 shows that the photoelectric conversion performance of Example 1 is better than that of Comparative Example 1 and Comparative Example 2, because A1 of Example 1 is in the range of 5:1 to 8:1. In this range, the second passivation layer can provide sufficient hydrogen to enter the first passivation layer and the first intrinsic silicon layer, thereby passivating the defects of the first passivation layer and the first intrinsic silicon layer, and improving the carrier transmission capacity in the first passivation layer and the first intrinsic silicon layer; and the matching degree of A1 and A2 is high, which helps to improve the anti-ultraviolet effect of the solar cell to a high degree, ensure the high uniformity of the electric field transition in the second passivation layer and the third passivation layer, and promote the transmission of carriers at the interface between the second passivation layer and the third passivation layer.

[0117] Analysis of the data of Example 1, Comparative Example 3 and Comparative Example 4 shows that the photoelectric conversion performance of Example 1 is better than that of Comparative Example 3 and Comparative Example 4, because A2 in Example 1 is in the range of 20:1 to 50:1. In this range, the matching degree of A2 and A1 is high, thereby improving the anti-ultraviolet effect of the solar cell to a high degree, and ensuring high uniformity of the electric field transition in the second passivation layer and the third passivation layer.

[0118] Analysis of the data of Example 1 and Example 2 shows that the photoelectric conversion performance of Example 1 is better than that of Example 2, because the matching degree of A1 and A3 in Example 1 is higher. Therefore, the matching degree of the electric field between the first passivation layer and the second passivation layer is higher, which helps to further reduce the transmission barrier of carriers when transmitting at the interface, effectively improves the transmission performance of carriers, and thus helps to further improve the performance of solar cells.

[0119] Analysis of the data of Example 1 and Example 3 shows that the photoelectric conversion performance of Example 1 is better than that of Example 3, because the A4 in the fourth passivation layer on the backlight surface of Example 1 is 60:1. Therefore, the fourth passivation layer can provide sufficient hydrogen to enter the second intrinsic silicon layer, so that the hydrogen entering the second intrinsic silicon layer can contact the backlight surface of the silicon substrate, passivate the backlight surface of the silicon substrate, and help to further improve the passivation effect of the backlight surface, which effectively promotes the improvement of the photoelectric conversion performance of the solar cell; and the fifth passivation layer and the sixth passivation layer are also arranged on the fourth passivation layer in Example 1, so through the coordinated cooperation of these passivation layers, it is helpful to further improve the passivation effect of the backlight surface of the silicon substrate.

[0120] Analysis of the data of Example 1, Example 4 and Example 5 shows that the performance of Example 1 is better than that of Example 4 and Example 5, because A4 in Example 1 is in the range of 40:1 to 70:1. Therefore, Example 1 can provide an appropriate amount of hydrogen to enter the second intrinsic silicon layer, thereby contacting the backlight surface of the silicon substrate, further passivating the backlight surface of the silicon substrate, thereby further improving the passivation performance of the backlight surface.

[0121] 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, the silicon substrate having a light-receiving surface and a light-receiving surface arranged opposite to each other, and a first composite passivation layer, a first doping layer, a first transparent conductive layer, and a first electrode arranged in sequence on the light-receiving surface of the silicon substrate; Wherein, the first composite passivation layer comprises: a first intrinsic silicon layer, wherein the first intrinsic silicon layer is disposed on the silicon substrate; A first passivation layer, wherein the first passivation layer is disposed on a side of the first intrinsic silicon layer away from the silicon substrate; a second passivation layer, the second passivation layer being disposed on a side of the first passivation layer away from the first intrinsic silicon layer; a third passivation layer, the third passivation layer being disposed on a side of the second passivation layer facing away from the first passivation layer; The second passivation layer and the third passivation layer are configured to be prepared by hydrogen and silane, the flow ratio of the hydrogen and the silane used to prepare the second passivation layer is A1, and the flow ratio of the hydrogen and the silane used to prepare the third passivation layer is A2, and A1 and A2 satisfy: 5:1≤A1≤10:1, 20:1≤A2≤50:

1.

2. The solar cell according to claim 1, characterized in that: A1 and A2 satisfy: A1:A2=(1:10)~(1:2).

3. The solar cell according to claim 1, characterized in that: The first passivation layer is configured to be prepared by the hydrogen and the silane, and a flow ratio of the hydrogen and the silane in the first passivation layer is A3, the A3 is less than the A1, and the A3 satisfies: A3≤5:

1.

4. The solar cell according to claim 1, characterized in that: The thickness of the first passivation layer is H1, the thickness of the second passivation layer is H2, and the thickness of the third passivation layer is H3. H1, H2, and H3 satisfy: H2>H1, H2>H3.

5. The solar cell according to claim 4, characterized in that: The H1 satisfies: 0 nm<H1≤1 nm; and / or, The H2 satisfies: 3 nm≤H2≤5 nm; and / or, The H3 satisfies: 0 nm<H3≤2 nm.

6. The solar cell according to claim 1, characterized in that: The crystallization rate of the third passivation layer is 7.5% to 10%, and the crystallization rate of the first doping layer is 10% to 40%.

7. The solar cell according to any one of claims 1 to 6, characterized in that: The crystallization rate of the first passivation layer is 1% to 5%; and / or, The crystallization rate of the second passivation layer is 5% to 7.5%; and / or, The thickness of the first intrinsic silicon layer is H4, and H4 satisfies: 0 nm<H4≤0.5 nm.

8. The solar cell according to claim 1, characterized in that: A second composite passivation layer, a second doping layer, a second transparent conductive layer, and a second electrode are sequentially arranged on the backlight surface of the silicon substrate; Wherein, the second composite passivation layer comprises: a second intrinsic silicon layer, wherein the second intrinsic silicon layer is disposed on the silicon substrate; a fourth passivation layer, the fourth passivation layer being disposed on a side of the second intrinsic silicon layer facing away from the silicon substrate; The fourth passivation layer is configured to be prepared by the hydrogen and the silane, and a flow ratio of the hydrogen and the silane used to prepare the fourth passivation layer is A4, and the A4 satisfies: 40:1≤A4≤70:

1.

9. The solar cell according to claim 8, characterized in that: The second composite passivation layer further comprises: a fifth passivation layer, the fifth passivation layer being disposed on a surface of the fourth passivation layer facing away from the silicon substrate; a sixth passivation layer, the sixth passivation layer being disposed on a surface of the fifth passivation layer facing away from the silicon substrate; The fifth passivation layer and the sixth passivation layer are configured to be prepared by the hydrogen and the silane, the flow ratio of the hydrogen and the silane used to prepare the fifth passivation layer is A5, and the flow ratio of the hydrogen and the silane used to prepare the sixth passivation layer is A6, and the A4, the A5 and the A6 show a downward trend, and the A5 and the A6 satisfy: 30:1≤A5≤60:1, 25:1≤A6≤55:

1.

10. The solar cell according to claim 9, characterized in that: The thickness of the fourth passivation layer is H5, the thickness of the fifth passivation layer is H6, and the thickness of the sixth passivation layer is H7. H5, H6, and H7 satisfy: H6>H5, H6>H7.

11. The solar cell according to claim 10, characterized in that: The H5 satisfies: 0 nm<H5≤1 nm; and / or, The H6 satisfies: 3 nm≤H6≤5 nm; and / or, The H7 satisfies: 0 nm<H7≤1.5 nm.

12. The solar cell according to any one of claims 9 to 11, characterized in that: The thickness of the second intrinsic silicon layer is H8, and H8 satisfies: 0 nm<H8≤0.5 nm; and / or, The thickness of the sixth passivation layer is smaller than the thickness of the third passivation layer.

13. A method for preparing a solar cell, characterized in that: The preparation method comprises the following steps: A first intrinsic silicon layer is prepared on a light-receiving surface of a silicon substrate, a first passivation layer is prepared on the first intrinsic silicon layer, a second passivation layer is prepared on the first passivation layer by hydrogen and silane, and a third passivation layer is prepared on the second passivation layer by hydrogen and silane to obtain a first composite passivation layer; wherein the flow ratio of the hydrogen and the silane used to prepare the second passivation layer is A1, and the flow ratio of the hydrogen and the silane used to prepare the third passivation layer is A2, and A1 and A2 satisfy: 5:1≤A1≤10:1, 20:1≤A2≤50:1; preparing a first doping layer on the third passivation layer; preparing a first transparent conductive layer on the first doped layer; A first electrode is prepared on the first transparent conductive layer to obtain the solar cell.

14. The preparation method according to claim 13, characterized in that: In the step of preparing the first intrinsic silicon layer on the light-receiving surface of the silicon substrate, the preparation parameters include: the process gas includes SiH4, the gas pressure is 0.6 Torr~0.97 Torr, the ignition power is 800 W~1200 W, the ignition time is 1 s~2 s, and the flow rate of SiH4 is 800 sccm~1800 sccm; and / or, In the step of preparing the second passivation layer on the first passivation layer by hydrogen and silane, the process gas includes SiH4 and H2, the gas pressure is 0.5 Torr~0.57 Torr, the ignition power is 600 W~800 W, the ignition time is 15 s~25 s, the flow rate of SiH4 is 600 sccm~1200 sccm, and the flow rate of H2 is 3000 sccm~12000 sccm; and / or, In the step of preparing the third passivation layer on the second passivation layer by the hydrogen and the silane, the preparation parameters include: the process gas includes SiH4 and H2, the gas pressure is 0.5 Torr~0.57 Torr, the ignition power is 600 W~800 W, the ignition time is 10 s~15 s, the flow rate of SiH4 is 600 sccm~1200 sccm, and the flow rate of H2 is 12000 sccm~60000 sccm.

15. The preparation method according to claim 14, characterized in that: The step of preparing a first passivation layer on the first intrinsic silicon layer includes: preparing a first passivation layer on the first intrinsic silicon layer using the hydrogen and the silane, wherein a flow ratio of the hydrogen and the silane in the first passivation layer is A3, and A3 is less than A1, and A3 satisfies: A3≤5:

1.

16. The preparation method according to claim 15, characterized in that: The preparation parameters include: process gases include SiH4 and H2, gas pressure is 0.5 Torr~0.57 Torr, ignition power is 400 W~600 W, ignition time is 2 s~4 s, SiH4 flow rate is 200 sccm~600 sccm, and H2 flow rate is 200 sccm~3000 sccm.

17. The preparation method according to claim 13, characterized in that: After the step of preparing the first composite passivation layer and before the step of preparing the first doping layer on the third passivation layer, the method for preparing a solar cell further includes: preparing a second intrinsic silicon layer on the backlight side of the silicon substrate, and preparing a fourth passivation layer on the surface of the second intrinsic silicon layer facing away from the silicon substrate by using the hydrogen and the silane to prepare a second composite passivation layer; wherein the flow ratio of the hydrogen and the silane used to prepare the fourth passivation layer is A4, and A4 satisfies: 40:1≤A4≤70:

1.

18. The preparation method according to claim 17, characterized in that: In the step of preparing the second intrinsic silicon layer on the backlight surface of the silicon substrate, the preparation parameters include: the process gas includes SiH4, the gas pressure is 0.7 Torr~0.97 Torr, the ignition power is 800 W~1200 W, the ignition time is 1 s~2 s, and the flow rate of SiH4 is 800 sccm~1800 sccm; and / or, In the step of preparing a fourth passivation layer by using the hydrogen and the silane on the surface of the second intrinsic silicon layer facing away from the silicon substrate, the preparation parameters include: the process gas includes SiH4 and H2, the gas pressure is 0.5 Torr~0.57 Torr, the ignition power is 400 W~600 W, the ignition time is 2 s~4 s, the flow rate of SiH4 is 200 sccm~600 sccm, and the flow rate of H2 is 8000 sccm~42000 sccm.

19. The preparation method according to claim 17, characterized in that: After the step of preparing a fourth passivation layer on a surface of the second intrinsic silicon layer away from the silicon substrate by using the hydrogen and the silane, and before the step of preparing a first doped layer on the third passivation layer, the method for preparing a solar cell further includes: sequentially preparing a fifth passivation layer and a sixth passivation layer on a surface of the fourth passivation layer away from the silicon substrate by using the hydrogen and the silane, wherein a flow ratio of the hydrogen and the silane for preparing the fifth passivation layer is A5, and a flow ratio of the hydrogen and the silane for preparing the sixth passivation layer is A6, and A4, A5 and A6 show a downward trend, and A5 and A6 satisfy: 30:1≤A5≤60:1, 25:1≤A6≤55:

1.

20. The preparation method according to claim 19, characterized in that: In the step of preparing the fifth passivation layer, the preparation parameters include: the process gas includes SiH4 and H2, the gas pressure is 0.5 Torr~0.57 Torr, the ignition power is 600 W~800 W, the ignition time is 15 s~25 s, the flow rate of SiH4 is 600 sccm~1200 sccm, and the flow rate of H2 is 18000 sccm~72000 sccm; and / or, In the step of preparing the sixth passivation layer, the preparation parameters include: the process gas includes SiH4 and H2, the gas pressure is 0.5Torr~0.57 Torr, the ignition power is 800 W~1000 W, the ignition time is 5 s~10 s, the flow rate of SiH4 is 600sccm~1200 sccm, and the flow rate of H2 is 15000 sccm~66000 sccm.

21. The preparation method according to claim 19 or 20, characterized in that: After the step of preparing the first doping layer on the third passivation layer and before the step of preparing the first transparent conductive layer on the first doping layer, the method for preparing a solar cell includes: preparing a second doping layer on the second composite passivation layer; After the step of preparing a first transparent conductive layer on the first doped layer and before the step of preparing a first electrode on the first transparent conductive layer, the method for preparing a solar cell includes: preparing a second transparent conductive layer on the second doped layer; After the step of preparing the first electrode on the first transparent conductive layer, the method for preparing the solar cell includes: preparing the second electrode on the second transparent conductive layer.

22. A photovoltaic module, characterized in that: include: The solar cell according to any one of claims 1 to 12, or the solar cell prepared by the preparation method according to any one of claims 13 to 21.

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