Passivation anti-reflection layer, solar cell and photovoltaic system

Abstract

The utility model provides a passivation anti-reflection layer, a solar cell and a photovoltaic system. The passivation anti-reflection layer comprises a passivation layer, a hydrogen-rich barrier layer and an anti-reflection layer which are stacked in sequence, the passivation anti-reflection layer is applied to the front face and / or the back face of the solar cell, and the phenomenon that the hydrogen concentration in the passivation anti-reflection layer is decreased progressively from the side close to the silicon substrate layer to the side away from the silicon substrate layer can be effectively avoided; therefore, outward escape of hydrogen in the passivation layer in the direction away from the silicon substrate layer is reduced to a certain extent, hydrogen in the passivation anti-reflection layer is promoted to enter the silicon substrate layer inwards, dangling bonds on the surface of the silicon substrate are effectively hydrogenated, surface defects are reduced, the minority carrier lifetime of the silicon substrate is remarkably prolonged, the passivation effect is improved, the open-circuit voltage is increased, and the cell efficiency is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of solar cells, and in particular to a passivation anti-reflection layer, a solar cell and a photovoltaic system. Background Art

[0002] In crystalline silicon solar cells, the reflectivity of bare silicon is very high, and the light utilization rate is low, which will cause the efficiency of solar cells to decrease. In order to reduce the reflection of light on the surface of solar cells, one or more layers of thin films that effectively reduce the reflection of light, namely anti-reflection layers, are usually plated on the surface of the cell. Silicon nitride film is commonly used as an anti-reflection layer in the industry, and a refractive index gradient change design is made to better meet the anti-reflection conditions of crystalline silicon cells. The hydrogen passivation effect of silicon nitride film is related to the hydrogen content. When the refractive index of the anti-reflection layer decreases from the side close to the silicon substrate layer to the side away from the silicon substrate layer, resulting in a decrease in hydrogen content, during the post-annealing process, the concentration gradient of the hydrogen content in the anti-reflection layer will cause part of the hydrogen to passivate the interface defect state of the silicon substrate layer inward under the action of heat, and the other part of the hydrogen will escape outward along the direction of the concentration gradient, resulting in poor hydrogen passivation effect of silicon nitride film. Utility Model Content

[0003] In view of this, the utility model provides a passivation anti-reflection layer, a solar cell and a photovoltaic system. The passivation anti-reflection layer comprises a three-layer structure of a passivation layer, a hydrogen-rich barrier layer and an anti-reflection layer stacked in sequence. The passivation anti-reflection layer is applied to the front and / or back of the solar cell, which can effectively avoid the phenomenon that the hydrogen concentration in the passivation anti-reflection layer decreases from the side close to the silicon substrate layer to the side away from the silicon substrate layer, thereby reducing the hydrogen in the passivation layer to escape outward in the direction away from the silicon substrate layer to a certain extent, and promoting the hydrogen in the passivation anti-reflection layer to enter the silicon substrate layer inward, effectively hydrogenating the dangling bonds on the surface of the silicon substrate and reducing surface defects, thereby significantly improving its minority carrier lifetime, improving the passivation effect, increasing the open circuit voltage, and improving the battery efficiency.

[0004] The utility model provides a passivation anti-reflection layer in a first aspect. The passivation anti-reflection layer comprises a passivation layer, a hydrogen-rich barrier layer and an anti-reflection layer which are stacked in sequence.

[0005] Optionally, the thickness ratio of the passivation layer, the hydrogen-rich barrier layer and the anti-reflection layer is (6-8):1:(5-7).

[0006] Optionally, the thickness of the passivation anti-reflection layer is 75nm-95nm; the refractive index of the passivation anti-reflection layer is 1.9-2.1.

[0007] Optionally, the hydrogen-rich barrier layer is a stack of one or more of an intrinsic hydrogenated amorphous silicon layer and a hydrogen-rich silicon carbide layer.

[0008] Optionally, the passivation layer is a silicon nitride layer, or a stacked silicon oxide layer and a silicon nitride layer.

[0009] Optionally, the anti-reflection layer includes one or more anti-reflection sub-layers, and the anti-reflection sub-layers are silicon nitride layers, silicon oxynitride layers or silicon oxide layers.

[0010] Optionally, the anti-reflection layer includes a plurality of anti-reflection sub-layers, and the refractive index of the plurality of anti-reflection sub-layers decreases layer by layer along a direction from the passivation layer to the anti-reflection layer.

[0011] A second aspect of the utility model provides a solar cell, wherein the solar cell comprises the passivation anti-reflection layer provided by the first aspect of the utility model.

[0012] Optionally, the solar cell includes a first passivation anti-reflection layer, an aluminum oxide passivation layer, a first doped layer, a silicon substrate layer, a silicon oxide tunneling layer, a second doped layer and a second passivation anti-reflection layer which are stacked in sequence; the first passivation anti-reflection layer and / or the second passivation anti-reflection layer is the passivation anti-reflection layer, wherein the passivation layer side of the passivation anti-reflection layer is close to the silicon substrate layer.

[0013] Optionally, the first doped layer is a P-type doped layer; the silicon substrate layer is an N-type silicon substrate layer; and the second doped layer is a phosphorus-doped polysilicon layer.

[0014] Optionally, the thickness of the aluminum oxide passivation layer is 3nm-7nm; the thickness of the first doping layer is 1.3μm-1.5μm; the thickness of the silicon substrate layer is 110μm-165μm; the thickness of the silicon oxide tunneling layer is 1.0nm-1.6nm; and the thickness of the second doping layer is 40nm-120nm.

[0015] Optionally, the solar cell includes a first passivation anti-reflection layer, a silicon oxide layer, a phosphorus layer emitter, a silicon substrate layer, an aluminum oxide layer, a second passivation anti-reflection layer and an aluminum back field which are stacked in sequence; the first passivation anti-reflection layer and / or the second passivation anti-reflection layer is the passivation anti-reflection layer, wherein the passivation layer side of the passivation anti-reflection layer is close to the silicon substrate layer; the silicon substrate layer is a P-type silicon substrate layer.

[0016] A third aspect of the present invention provides a photovoltaic system, which includes the solar cell provided by the second aspect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the cross-sectional structure of a passivation anti-reflection layer provided in one embodiment of the utility model;

[0018] Figure 2 A schematic diagram of the cross-sectional structure of a passivation anti-reflection layer provided in another embodiment of the utility model;

[0019] Figure 3 A schematic diagram of the cross-sectional structure of a solar cell provided in one embodiment of the utility model;

[0020] Figure 4 A schematic diagram of the cross-sectional structure of a solar cell provided in another embodiment of the utility model;

[0021] Figure 5 A schematic diagram of the cross-sectional structure of a solar cell provided in yet another embodiment of the utility model;

[0022] Figure 6 A schematic diagram of the cross-sectional structure of a solar cell provided in yet another embodiment of the utility model;

[0023] Figure 7 A schematic diagram of the cross-sectional structure of another solar cell provided in one embodiment of the utility model.

[0024] Description of Figure Numbers

[0025] 100-passivation anti-reflection layer; 101-passivation layer; 102-hydrogen-rich barrier layer; 103-anti-reflection layer; 1031-first anti-reflection sublayer; 1032-second anti-reflection sublayer; 1033-third anti-reflection sublayer; 200-solar cell; 10-first passivation anti-reflection layer; 20-aluminum oxide passivation layer; 30-first doping layer; 40-silicon substrate layer; 50-silicon oxide tunneling layer; 60-second doping layer; 70-second passivation anti-reflection layer; 80-first electrode; 90-second electrode; 21-silicon oxide layer; 31-phosphorus layer emitter; 51-aluminum oxide layer; 61-aluminum back field; 81-front electrode. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0027] In crystalline silicon solar cells, the reflectivity of bare silicon is very high, and the light utilization rate is low, which will cause the efficiency of solar cells to decrease. In order to reduce the reflection of light on the surface of solar cells, one or more layers of thin films that effectively reduce the reflection of light, namely anti-reflection layers, are usually selected to be coated on the surface of the cell. Silicon nitride thin films are commonly used as anti-reflection layers in the industry, and a design with a gradient change in refractive index is made to better meet the anti-reflection conditions of crystalline silicon cells. Generally speaking, the higher the refractive index, the higher the corresponding hydrogen content, and the hydrogen passivation effect of silicon nitride thin films is related to the hydrogen content. The higher the hydrogen content, the better the hydrogen passivation effect. When the refractive index of the anti-reflection layer decreases from the side close to the silicon substrate layer to the side away from the silicon substrate layer, resulting in a decrease in hydrogen content, during the post-annealing process, the concentration gradient of the hydrogen content in the anti-reflection layer will cause part of the hydrogen to passivate the interface defect state of the silicon substrate layer inward under the action of thermal promotion, and the other part of the hydrogen will escape outward along the direction of the concentration gradient, resulting in poor hydrogen passivation effect of silicon nitride thin films.

[0028] In view of this, the utility model provides a passivation anti-reflection layer, a solar cell and a photovoltaic system. The passivation anti-reflection layer comprises a three-layer structure of a passivation layer, a hydrogen-rich barrier layer and an anti-reflection layer stacked in sequence. The passivation anti-reflection layer is applied to the front and / or back of the solar cell, which can effectively avoid the phenomenon that the hydrogen concentration in the passivation anti-reflection layer decreases from the side close to the silicon substrate layer to the side away from the silicon substrate layer, thereby reducing the hydrogen in the passivation layer to escape outward in the direction away from the silicon substrate layer to a certain extent, and promoting the hydrogen in the passivation anti-reflection layer to enter the silicon substrate layer inward, effectively hydrogenating the dangling bonds on the surface of the silicon substrate and reducing surface defects, thereby significantly improving its minority carrier lifetime, improving the passivation effect, increasing the open circuit voltage, and improving the battery efficiency.

[0029] See also Figure 1 and Figure 2, the embodiment of the utility model provides a passivation anti-reflection layer 100, the passivation anti-reflection layer comprises a passivation layer 101, a hydrogen-rich barrier layer 102 and an anti-reflection layer 103 which are stacked in sequence. The passivation anti-reflection layer 100 provided by the embodiment of the utility model is applied to a solar cell, one side of the passivation layer 101 is close to the silicon substrate layer of the solar cell, one side of the anti-reflection layer 103 is far away from the silicon substrate layer of the solar cell, and the hydrogen-rich barrier layer 102 is located between the passivation layer 101 and the anti-reflection layer 103. The utility model specially designs the structure of the passivation anti-reflection layer located on the front and / or back of the solar cell. Compared with the traditional three-layer silicon nitride layer structure, the utility model adds a hydrogen-rich barrier layer 102 in the passivation layer 101 with a higher refractive index and the anti-reflection layer 103 with a lower refractive index. The hydrogen-rich barrier layer can effectively avoid the phenomenon that the hydrogen concentration in the passivation anti-reflection layer decreases from the side close to the substrate to the outside, thereby effectively inhibiting the hydrogen in the passivation anti-reflection layer close to the substrate from escaping outward to a certain extent, and then promoting the hydrogen in the passivation anti-reflection layer to enter the silicon substrate inward, effectively hydrogenating the dangling bonds and reducing surface defects, thereby significantly improving its minority carrier lifetime, improving passivation, and increasing the open circuit voltage.

[0030] In some embodiments of the present invention, the thickness ratio of the passivation layer 101, the hydrogen-rich barrier layer 102 and the anti-reflection layer 103 is (6-8):1:(5-7). In some specific embodiments of the present invention, the thickness ratio of the passivation layer, the hydrogen-rich barrier layer and the anti-reflection layer can be, for example, 6:1:5, 7:1:6, 8:1:7. The passivation anti-reflection layer of the present invention controls the thickness ratio of the passivation layer, the hydrogen-rich barrier layer and the anti-reflection layer within a suitable range, so that the passivation layer can have a sufficient thickness to provide hydrogen for passivation. The hydrogen-rich barrier layer can avoid the negative impact of excessive thickness on the overall anti-reflection effect of the passivation anti-reflection layer while ensuring that it effectively blocks the escape of hydrogen. The anti-reflection layer can make better use of the sunlight reflected from the ground, thereby improving the utilization rate of sunlight by solar cells.

[0031] In an embodiment of the present invention, the thickness of the passivation anti-reflection layer is in the range of 75nm-95nm. In some embodiments of the present invention, the thickness of the passivation anti-reflection layer may be, for example, 75nm, 76nm, 78nm, 80nm, 82nm, 84nm, 85nm, 86nm, 88nm, 90nm, 92nm, 94nm, 95nm. In an embodiment of the present invention, the refractive index of the passivation anti-reflection layer is 1.9-2.1. In some embodiments of the present invention, the refractive index of the passivation anti-reflection layer may be, for example, 1.9, 1.92, 1.95, 1.96, 1.98, 2.0, 2.02, 2.05, 2.06, 2.08, 2.1. By controlling the thickness and refractive index of the passivation anti-reflection layer within a suitable range, the passivation anti-reflection layer can have both excellent passivation and anti-reflection effects.

[0032] In some embodiments of the present invention, the passivation anti-reflection layer 100 can be respectively arranged on the front and / or back of the solar cell. The passivation anti-reflection layer 100 includes a passivation layer 101, a hydrogen-rich barrier layer 102 and an anti-reflection layer 103, which are stacked in sequence from the direction close to the silicon substrate layer to the direction away from the silicon substrate layer. The passivation layer 101 in the passivation anti-reflection layer 100 is located on the side close to the silicon substrate layer, and the hydrogen content therein is relatively high, which can play a role in passivating the defects and dangling bonds at the interface of the solar cell, thereby reducing the recombination of carriers. Since there are reactive dangling bonds on the silicon atoms of the silicon substrate, these dangling bonds will affect the band gap energy of the material. The hydrogen in the passivation layer 101 of the present invention can react with these dangling bonds (Si·) to generate stable Si-H bonds, thereby playing a role in passivating the silicon substrate layer, thereby improving the stability and service life of the solar cell. In some embodiments of the present invention, the passivation layer 101 can be a silicon nitride layer. In some other embodiments of the present invention, the passivation layer 101 may also be a stacked silicon oxide layer and a silicon nitride layer, wherein the silicon oxide layer is located on the side close to the silicon substrate layer, and the silicon nitride layer is located on the side away from the silicon substrate. Compared with silicon nitride, silicon oxide has better lattice matching with the silicon substrate. By adding a silicon oxide layer in the passivation layer 101, the lattice matching between the passivation layer 101 and the silicon substrate can be better improved.

[0033] In the embodiment of the present invention, the anti-reflection layer 103 in the passivation anti-reflection layer 100 is located on the side away from the silicon substrate, which can effectively reduce the reflection of light. In the embodiment of the present invention, the anti-reflection layer 103 may include one or more anti-reflection sub-layers. In some embodiments, the anti-reflection layer 103 includes multiple anti-reflection sub-layers, and the number of anti-reflection sub-layers may be, for example, 2, 3, or 4. Figure 1 As shown, in some embodiments of the present invention, the anti-reflection layer 103 includes two anti-reflection sub-layers, namely a first anti-reflection sub-layer 1031 and a second anti-reflection sub-layer 1032. Figure 2 As shown, in some other embodiments of the present invention, the anti-reflection layer 103 includes three anti-reflection sub-layers, namely, a first anti-reflection sub-layer 1031 , a second anti-reflection sub-layer 1032 and a third anti-reflection sub-layer 1033 .

[0034] In the embodiment of the utility model, the anti-reflection layer is a silicon nitride layer, a silicon oxynitride layer or a silicon oxide layer. Figure 2Taking the anti-reflection layer provided as an example, the materials of each anti-reflection sublayer of the anti-reflection layer 103, namely the first anti-reflection sublayer 1031, the second anti-reflection sublayer 1032 and the third anti-reflection sublayer 1033, can be the same or different. In some specific embodiments of the utility model, the first anti-reflection sublayer 1031, the second anti-reflection sublayer 1032 and the third anti-reflection sublayer 1033 can all be, for example, silicon nitride layers. In some specific embodiments of the utility model, the first anti-reflection sublayer 1031 can be, for example, a silicon nitride layer, the second anti-reflection sublayer 1032 can be, for example, a silicon oxynitride layer, and the third anti-reflection sublayer 1033 can be, for example, a silicon oxide layer. In other specific embodiments of the utility model, the first anti-reflection sublayer 1031 and the second anti-reflection sublayer 1032 can be, for example, silicon nitride layers, and the third anti-reflection sublayer 1033 can be, for example, a silicon oxide layer. The structure of the anti-reflection layer 103 of the utility model includes but is not limited to the above specific examples.

[0035] In some embodiments of the present invention, the anti-reflection layer 103 includes a plurality of anti-reflection sub-layers, and the refractive index of the anti-reflection sub-layers in the anti-reflection layer 103 decreases layer by layer along the direction from the passivation layer to the anti-reflection layer. When applied to a solar cell, the refractive index of the anti-reflection sub-layers in the anti-reflection layer 103 decreases layer by layer from the side close to the silicon substrate layer of the solar cell to the side away from the silicon substrate layer of the solar cell. Figure 1 Taking the anti-reflection layer provided as an example, the anti-reflection layer 103 includes two anti-reflection sub-layers, namely a first anti-reflection sub-layer 1031 and a second anti-reflection sub-layer 1032. In some specific embodiments of the present invention, the refractive index of the first anti-reflection sub-layer 1031 may be, for example, 2.1-2.3, and the refractive index of the second anti-reflection sub-layer 1032 may be, for example, 1.9-2.05. Figure 2 Taking the anti-reflection layer provided as an example, the anti-reflection layer 103 includes three anti-reflection sub-layers, namely the first anti-reflection sub-layer 1031, the second anti-reflection sub-layer 1032 and the third anti-reflection sub-layer 1033. In some specific embodiments of the utility model, the refractive index of the first anti-reflection sub-layer 1031 can be, for example, 2.2-2.3, the refractive index of the second anti-reflection sub-layer 1032 can be, for example, 2.05-2.15, and the refractive index of the third anti-reflection sub-layer 1033 can be, for example, 1.9-2.0. In the embodiment of the utility model, the difference in refractive index between any two adjacent anti-reflection sub-layers can be the same or different. By setting an anti-reflection layer structure with a gradient refractive index change, the overall thickness and refractive index of the anti-reflection layer can meet the anti-reflection conditions of the solar cell.

[0036] In the embodiment of the utility model, the hydrogen-rich barrier layer 102 in the passivation anti-reflection layer 100 is located between the passivation layer 101 and the anti-reflection layer 103, and plays an effective role in preventing the hydrogen in the passivation anti-reflection layer from escaping outwards. In some embodiments of the utility model, the hydrogen-rich barrier layer is a stack of one or more of an intrinsic hydrogenated amorphous silicon layer and a hydrogen-rich silicon carbide layer, and the mass percentage of hydrogen atoms in the intrinsic hydrogenated amorphous silicon layer and / or the hydrogen-rich silicon carbide layer is greater than or equal to 35%. By selecting a material that can effectively prevent hydrogen from escaping as a hydrogen-rich barrier layer and adding it between the passivation layer and the anti-reflection layer, the change of the hydrogen concentration gradient in the passivation anti-reflection layer can be avoided, thereby reducing the hydrogen in the passivation anti-reflection layer from escaping outwards to a certain extent, and promoting more hydrogen to enter the silicon substrate inwards, effectively passivating dangling bonds and surface defects, reducing the interface state density, and significantly improving the minority carrier lifetime.

[0037] The present invention also provides a solar cell 200, which includes the passivation anti-reflection layer 100 described above. Figure 3 As shown, in some embodiments of the present application, the solar cell 200 can be a TOPCon (Tunnel Oxide Passivated Contact solar cell, tunnel oxide passivation contact) solar cell, including a first passivation anti-reflection layer 10, an aluminum oxide passivation layer 20, a first doping layer 30, a silicon substrate layer 40, a silicon oxide tunneling layer 50, a second doping layer 60 and a second passivation anti-reflection layer 70 stacked in sequence, wherein the first passivation anti-reflection layer 10 and / or the second passivation anti-reflection layer 70 is the passivation anti-reflection layer 100 provided in the embodiment of the utility model, and a first electrode 80 is further provided on the first passivation anti-reflection layer 10, and a second electrode 90 is further provided on the second passivation anti-reflection layer 70.

[0038] like Figure 4 As shown, in some specific embodiments of the present invention, the first passivation anti-reflection layer 10 is the passivation anti-reflection layer 100 provided in an embodiment of the present invention, wherein one side of the passivation layer 101 is close to the silicon substrate layer 40, one side of the anti-reflection layer 103 is away from the silicon substrate layer 40, and the hydrogen-rich barrier layer 102 is located between the passivation layer 101 and the anti-reflection layer 103; the second passivation anti-reflection layer 70 is a conventional anti-reflection layer in the field, including but not limited to one or more of a silicon nitride layer, a silicon oxide layer, and a silicon oxynitride layer.

[0039] like Figure 5As shown, in some other specific embodiments of the present invention, the second passivation anti-reflection layer 70 is the passivation anti-reflection layer 100 provided in an embodiment of the present invention, wherein one side of the passivation layer 101 is close to the silicon substrate layer 40, one side of the anti-reflection layer 103 is away from the silicon substrate layer 40, and the hydrogen-rich barrier layer 102 is located between the passivation layer 101 and the anti-reflection layer 103; the first passivation anti-reflection layer 10 is a conventional anti-reflection layer in the field, including but not limited to one or more of a silicon nitride layer, a silicon oxide layer, and a silicon oxynitride layer.

[0040] like Figure 6 As shown, in some specific embodiments of the present invention, the first passivation anti-reflection layer 10 and the second passivation anti-reflection layer 70 are both passivation anti-reflection layers 100 provided in embodiments of the present invention, wherein one side of the passivation layer 101 is close to the silicon substrate layer 40, and one side of the anti-reflection layer 103 is far away from the silicon substrate layer 40, and the hydrogen-rich barrier layer 102 is located between the passivation layer 101 and the anti-reflection layer 103.

[0041] In the embodiment of the utility model, the TOPCon solar cell is mainly based on an N-type silicon substrate, and an ultra-thin silicon oxide tunneling layer is prepared on the back of the cell and a doped polysilicon thin layer is deposited. The two together form a passivation contact structure, which is then annealed and recrystallized to enhance the passivation effect. Generally, during the use of solar cells, one side of the first passivation anti-reflection layer 10 faces the sunlight and is called the front side of the solar cell. Correspondingly, one side of the second passivation anti-reflection layer 70 is called the back side of the solar cell. Therefore, the first passivation anti-reflection layer 10 is also called the front passivation anti-reflection layer, and the second passivation anti-reflection layer 70 is also called the back passivation anti-reflection layer.

[0042] In the embodiment of the present invention, the thickness of the first passivation anti-reflection layer 10 and / or the second passivation anti-reflection layer 70 is in the range of 75nm-95nm. In some embodiments of the present invention, the thickness of the first passivation anti-reflection layer 10 and / or the second passivation anti-reflection layer 70 can be, for example, 75nm, 76nm, 78nm, 80nm, 82nm, 84nm, 85nm, 86nm, 88nm, 90nm, 92nm, 94nm, 95nm. The thickness of the first passivation anti-reflection layer 10 and the second passivation anti-reflection layer 70 can be the same or different.

[0043] In the embodiment of the present invention, the thickness of the aluminum oxide passivation layer 20 is 3nm-7nm. In some embodiments of the present invention, the thickness of the aluminum oxide passivation layer 20 can be, for example, 3nm, 3.5nm, 4nm, 4.5nm, 5nm, 5.5nm, 6nm, 6.5nm, 7nm. Controlling the thickness of the aluminum oxide passivation layer 20 within the above range can ensure that it brings a good passivation effect while not affecting the total thickness of the solar cell.

[0044] In an embodiment of the present invention, the first doping layer 30 is a P-type doping layer. In some embodiments of the present invention, the first doping layer 30 is a boron diffusion layer. In an embodiment of the present invention, the thickness of the first doping layer 30 is 1.3 μm-1.5 μm. In some specific embodiments of the present invention, the thickness of the first doping layer 30 can be, for example, 1.3 μm, 1.35 μm, 1.4 μm, 1.45 μm, 1.5 μm. It should be noted that in an embodiment of the present invention, the first doping layer 30 is a boron diffusion layer obtained by performing boron diffusion doping on a silicon substrate.

[0045] In an embodiment of the present invention, the silicon substrate layer 40 is an N-type silicon substrate layer. In some embodiments of the present invention, the thickness of the silicon substrate layer 40 is 110 μm-165 μm. Exemplarily, the thickness of the silicon substrate layer 40 includes but is not limited to 110 μm, 115 μm, 120 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm, 150 μm, 155 μm, 160 μm, 165 μm. In some embodiments of the present invention, the resistivity of the silicon substrate layer 40 may be 0.5 Ω·cm-2.2 Ω·cm. Exemplarily, the resistivity of the silicon substrate layer 40 includes but is not limited to 0.5Ω·cm, 0.6Ω·cm, 0.7Ω·cm, 0.8Ω·cm, 0.9Ω·cm, 1.0Ω·cm, 1.2Ω·cm, 1.3Ω·cm, 1.5Ω·cm, 1.6Ω·cm, 1.8Ω·cm, 2.0Ω·cm, 2.1Ω·cm, and 2.2Ω·cm.

[0046] In the embodiment of the present invention, the thickness of the silicon oxide tunneling layer 50 is 1.0nm-1.6nm. In some embodiments of the present invention, the thickness of the silicon oxide tunneling layer 50 can be, for example, 1.0nm, 1.1nm, 1.2nm, 1.3nm, 1.4nm, 1.5nm, 1.6nm. The embodiment of the present invention controls the thickness of the silicon oxide tunneling layer within the above range, which can better utilize the "tunneling effect", allowing electrons to pass smoothly and preventing the recombination of holes, thereby increasing the open circuit voltage of the battery through chemical passivation, thereby improving the conversion efficiency of the battery.

[0047] In an embodiment of the present invention, the second doped layer 60 is a phosphorus-doped polysilicon layer. In some embodiments of the present invention, the thickness of the second doped layer 60 is 40nm-120nm. In some specific embodiments of the present invention, the thickness of the second doped layer 60 can be, for example, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm. The phosphorus-doped polysilicon layer and the silicon oxide tunneling layer are stacked and the thickness is controlled within a suitable range, which can better achieve efficient passivation of the entire back side, improve carrier transport and charge collection capabilities, and thus improve the open circuit voltage and battery efficiency of the battery.

[0048] In some embodiments of the present invention, the first electrode 80 may be stacked on the surface of the first passivation anti-reflection layer 10, or may penetrate the first passivation anti-reflection layer 10 or be partially buried in the first passivation anti-reflection layer 10; in other embodiments of the present invention, the first electrode 80 may penetrate the first passivation anti-reflection layer 10 and extend to bury the aluminum oxide passivation layer 20 and the first doping layer 30. In some embodiments of the present invention, the second electrode 90 may penetrate the second passivation anti-reflection layer 70 and extend to bury the second doping layer 60.

[0049] like Figure 7 As shown, in some embodiments of the present application, the solar cell 200 can be a PERC (Passivated Emitter and Rear Cell) solar cell, including a first passivated anti-reflection layer 10, a silicon oxide layer 21, a phosphorus layer emitter 31, a silicon substrate layer 40, an aluminum oxide layer 51, a second passivated anti-reflection layer 70 and an aluminum back field 61 stacked in sequence; the first passivated anti-reflection layer 10 and / or the second passivated anti-reflection layer 70 is the passivated anti-reflection layer 100, and a front electrode 81 is also provided on the first passivated anti-reflection layer 10.

[0050] In some specific embodiments of the present invention, the first passivation anti-reflection layer 10 is the passivation anti-reflection layer 100 provided in an embodiment of the present invention, wherein one side of the passivation layer 101 is close to the silicon substrate layer 40, one side of the anti-reflection layer 103 is away from the silicon substrate layer 40, and the hydrogen-rich barrier layer 102 is located between the passivation layer 101 and the anti-reflection layer 103; the second passivation anti-reflection layer 70 is a conventional anti-reflection layer in the field, including but not limited to a silicon nitride layer.

[0051] In some other specific embodiments of the present invention, the second passivation anti-reflection layer 70 is the passivation anti-reflection layer 100 provided in an embodiment of the present invention, wherein one side of the passivation layer 101 is close to the silicon substrate layer 40, one side of the anti-reflection layer 103 is away from the silicon substrate layer 40, and the hydrogen-rich barrier layer 102 is located between the passivation layer 101 and the anti-reflection layer 103; the first passivation anti-reflection layer 10 is a conventional anti-reflection layer in the field, including but not limited to a silicon nitride layer.

[0052] In some specific embodiments of the present invention, the first passivation anti-reflection layer 10 and the second passivation anti-reflection layer 70 are both passivation anti-reflection layers 100 provided in embodiments of the present invention, wherein one side of the passivation layer 101 is close to the silicon substrate layer 40, one side of the anti-reflection layer 103 is far away from the silicon substrate layer 40, and the hydrogen-rich barrier layer 102 is located between the passivation layer 101 and the anti-reflection layer 103.

[0053] In the embodiment of the utility model, the PERC solar cell is mainly based on a P-type silicon substrate, that is, the silicon substrate layer 40 is a P-type silicon substrate layer. Generally, during the use of the solar cell, one side of the first passivation anti-reflection layer 10 faces the sunlight and is called the front side of the solar cell, and correspondingly, one side of the second passivation anti-reflection layer 70 is called the back side of the solar cell. Therefore, the first passivation anti-reflection layer 10 is also called the front passivation anti-reflection layer, and the second passivation anti-reflection layer 70 is also called the back passivation anti-reflection layer.

[0054] In the embodiment of the present invention, the thickness of the first passivation anti-reflection layer 10 and / or the second passivation anti-reflection layer 70 is in the range of 75nm-95nm. In some embodiments of the present invention, the thickness of the first passivation anti-reflection layer 10 and / or the second passivation anti-reflection layer 70 can be, for example, 75nm, 76nm, 78nm, 80nm, 82nm, 84nm, 85nm, 86nm, 88nm, 90nm, 92nm, 94nm, 95nm. The thickness of the first passivation anti-reflection layer 10 and the second passivation anti-reflection layer 70 can be the same or different.

[0055] It should be noted that the utility model Figure 3-Figure 7 In the figure, the first passivation anti-reflection layer 10, the aluminum oxide passivation layer 20, the silicon oxide layer 21, the first doped layer 30 and the phosphorus layer emitter 31 are wavy, which is only to cater to the pyramid-shaped light-trapping structure formed on one side surface (front side) of the silicon substrate layer 40 due to the texturing process. It is a commonly used drawing style in the field and does not constitute any limitation on the actual specific shapes of the first passivation anti-reflection layer 10, the aluminum oxide passivation layer 20, the silicon oxide layer 21, the first doped layer 30 and the phosphorus layer emitter 31 in the utility model.

[0056] In some embodiments of the present invention, the preparation of a solar cell may include the following steps:

[0057] S101, performing texturing treatment on the front and back sides of the N-type crystalline silicon substrate;

[0058] S102, performing boron diffusion treatment on the front side of the N-type crystalline silicon substrate to form a boron-doped layer and a borosilicate glass layer distributed on the surface thereof; removing all the borosilicate glass layers on the surface of the boron-doped layer, and removing the boron-doped layer on the back side of the N-type crystalline silicon substrate to obtain a first doped layer distributed only on the front side of the N-type crystalline silicon substrate;

[0059] S103, growing a silicon oxide tunneling layer on the back side of the N-type crystalline silicon substrate;

[0060] S104, depositing an amorphous silicon layer on the surface of the silicon oxide tunneling layer and then annealing the layer to obtain a second doped layer;

[0061] S105, depositing aluminum oxide on the front side of the N-type crystalline silicon substrate after the boron diffusion treatment to obtain an aluminum oxide passivation layer;

[0062] S106, depositing a passivation anti-reflection layer on the surface of the aluminum oxide passivation layer and the second doping layer; the passivation anti-reflection layer is deposited in the order of the passivation layer, the hydrogen-rich barrier layer and the anti-reflection layer;

[0063] S107, obtaining a solar cell after printing electrodes, sintering and light injection.

[0064] In some embodiments of the utility model, the diffusion temperature of the boron diffusion treatment in step S102 can be 900℃-1100℃, and the diffusion time can be 120min-240min; in step S103, the method of growing the silicon oxide tunneling layer includes but is not limited to thermal oxidation and plasma enhanced chemical vapor deposition; in step S104, the deposition temperature of the amorphous silicon layer can be 250℃-650℃, the annealing temperature can be 800℃-950℃, and the annealing time can be 30min-120min.

[0065] In some specific embodiments of the utility model, the method for depositing the passivation anti-reflection layer in step S106 is a plasma enhanced chemical vapor deposition method, and the temperature of the substrate is 350°C-450°C; the silane flow rate when depositing the passivation layer is 2000sccm-3000sccm, the power is 15kW-20kW, and the pressure is 150Pa-250 Pa; the silane flow rate when depositing the hydrogen-rich barrier layer is 1000sccm-2000sccm; when depositing the anti-reflection layer, the silane flow rate for depositing the first layer of silicon nitride is 700sccm-1000sccm, the power is 15kW-20kW, and the pressure is 150Pa-250 Pa, and the silane flow rate for depositing the second layer of silicon nitride is 700sccm-3000sccm, the power is 15kW-20kW, and the pressure is 200Pa.

[0066] The passivation anti-reflection layer provided by the utility model comprises a three-layer structure of a passivation layer, a hydrogen-rich barrier layer and an anti-reflection layer which are stacked in sequence. The passivation anti-reflection layer is applied to the front and / or back of the solar cell, which can effectively avoid the phenomenon that the hydrogen concentration in the passivation anti-reflection layer decreases from the side close to the silicon substrate layer to the side away from the silicon substrate layer, thereby reducing the hydrogen in the passivation layer to escape outward in the direction away from the silicon substrate layer to a certain extent, and promoting the hydrogen in the passivation anti-reflection layer to enter the silicon substrate layer inward, effectively hydrogenating the dangling bonds on the surface of the silicon substrate and reducing surface defects, thereby significantly improving its minority carrier lifetime, improving the passivation effect, increasing the open circuit voltage, and improving the battery efficiency.

[0067] The embodiment of the utility model further provides a photovoltaic system, which includes the solar cell provided in the utility model. The photovoltaic system improves the cell efficiency by using a solar cell with a passivation anti-reflection layer having a three-layer structure of a passivation layer, a hydrogen-rich barrier layer and an anti-reflection layer.

[0068] The above is an exemplary embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A passivation anti-reflection layer, characterized in that: The passivation anti-reflection layer comprises a passivation layer, a hydrogen-rich barrier layer and an anti-reflection layer which are stacked in sequence.

2. The passivation anti-reflection layer according to claim 1, characterized in that: The thickness ratio of the passivation layer, the hydrogen-rich barrier layer and the anti-reflection layer is (6-8):1:(5-7).

3. The passivation anti-reflection layer according to claim 1 or 2, characterized in that: The thickness of the passivation anti-reflection layer is 75nm-95nm; the refractive index of the passivation anti-reflection layer is 1.9-2.

1.

4. The passivation anti-reflection layer according to claim 1 or 2, characterized in that: The hydrogen-rich barrier layer is a stack of one or more of an intrinsic hydrogenated amorphous silicon layer and a hydrogen-rich silicon carbide layer.

5. The passivation anti-reflection layer according to claim 1 or 2, characterized in that: The passivation layer is a silicon nitride layer, or a stacked silicon oxide layer and a silicon nitride layer.

6. The passivation anti-reflection layer according to claim 1 or 2, characterized in that: The anti-reflection layer includes one or more anti-reflection sub-layers, and the anti-reflection sub-layers are silicon nitride layers, silicon oxynitride layers or silicon oxide layers.

7. The passivation anti-reflection layer according to claim 6, characterized in that: The anti-reflection layer includes a plurality of anti-reflection sub-layers, and the refractive index of the plurality of anti-reflection sub-layers decreases layer by layer along a direction from the passivation layer to the anti-reflection layer.

8. A solar cell, characterized in that: The solar cell comprises the passivation anti-reflection layer according to any one of claims 1 to 7.

9. The solar cell according to claim 8, characterized in that The solar cell includes a first passivation anti-reflection layer, an aluminum oxide passivation layer, a first doped layer, a silicon substrate layer, a silicon oxide tunneling layer, a second doped layer and a second passivation anti-reflection layer which are stacked in sequence; the first passivation anti-reflection layer and / or the second passivation anti-reflection layer is the passivation anti-reflection layer, wherein the passivation layer side of the passivation anti-reflection layer is close to the silicon substrate layer.

10. The solar cell according to claim 9, characterized in that The first doped layer is a P-type doped layer; the silicon substrate layer is an N-type silicon substrate layer; and the second doped layer is a phosphorus-doped polysilicon layer.

11. The solar cell according to claim 9 or 10, characterized in that: The thickness of the aluminum oxide passivation layer is 3nm-7nm; the thickness of the first doping layer is 1.3μm-1.5μm; the thickness of the silicon substrate layer is 110μm-165μm; the thickness of the silicon oxide tunneling layer is 1.0nm-1.6nm; and the thickness of the second doping layer is 40nm-120nm.

12. The solar cell according to claim 8, wherein: The solar cell includes a first passivation anti-reflection layer, a silicon oxide layer, a phosphorus layer emitter, a silicon substrate layer, an aluminum oxide layer, a second passivation anti-reflection layer and an aluminum back field which are stacked in sequence; the first passivation anti-reflection layer and / or the second passivation anti-reflection layer is the passivation anti-reflection layer, wherein the passivation layer side of the passivation anti-reflection layer is close to the silicon substrate layer; the silicon substrate layer is a P-type silicon substrate layer.

13. A photovoltaic system, characterized in that: The photovoltaic system comprises the solar cell according to any one of claims 8 to 12.

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