Solar cell and photovoltaic module
By introducing a phosphorus-carbon-oxygen-silicon compound dielectric layer with a thickness of less than 5 nm into the doped polycrystalline silicon layer, the problem of dopant elements damaging the tunneling oxide layer is solved, the open-circuit voltage and fill factor are improved, and the photoelectric conversion efficiency of the solar cell is enhanced.
Patent Information
- Application Number
- CN202423149650.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-19
- Publication Date
- 2026-02-27
- Estimated Expiration
- 2034-12-19
AI Technical Summary
In existing technologies, during the high-temperature annealing process of TOPCon solar cells, doping elements damage the tunneling oxide layer, leading to passivation failure, reducing open-circuit voltage and fill factor, and thus reducing cell efficiency.
Introducing a doped dielectric layer, particularly a phosphorus-carbon-oxygen silicon compound, with a thickness of less than 5 nm, into a doped polycrystalline silicon layer is used for field passivation and chemical passivation, preventing phosphorus atom diffusion, protecting the tunneling oxide layer, and improving electron mobility.
It improves the open-circuit voltage and fill factor, enhances the passivation effect, and improves the photoelectric conversion efficiency.
Smart Images
Figure CN223957905U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of photovoltaic, in particular to a solar cell and a photovoltaic module. BACKGROUND
[0002] TOPCon solar cell is full name of tunneling oxide passivated contact cell, the core of which is to form a tunneling oxide layer and a doped polysilicon layer on the back. PECVD deposition method has the advantages of fast deposition speed, large output and in-situ doping compared with LPCVD deposition method, and in-situ doping can further improve the doping concentration and conductivity to improve the efficiency of the cell.
[0003] However, in the related art, too high doping concentration in the polysilicon layer will cause the doping element (such as phosphorus) to damage the tunneling oxide layer in the subsequent high-temperature annealing and crystallization process, resulting in passivation failure, thereby reducing the open-circuit voltage and fill factor and reducing the efficiency. UTILITY MODEL CONTENT
[0004] The purpose of the present application is to provide a solar cell and a photovoltaic module, which has a higher open-circuit voltage and fill factor, thereby realizing efficiency improvement.
[0005] In order to achieve the above-mentioned purpose, in a first aspect, the present application provides a solar cell, comprising:
[0006] a silicon substrate;
[0007] a passivation contact structure, the passivation contact structure being arranged on the surface of the silicon substrate, the passivation contact structure comprising a first dielectric layer, a third doped polysilicon layer and a second dielectric layer arranged in sequence, wherein the first dielectric layer is connected with the silicon substrate;
[0008] a first doped polysilicon layer, the first doped polysilicon layer being arranged on the surface of the passivation contact structure away from the silicon substrate;
[0009] a doped dielectric layer, the doped dielectric layer being arranged on the surface of the first doped polysilicon layer away from the silicon substrate; and
[0010] a second doped polysilicon layer, the second doped polysilicon layer being arranged on the surface of the doped dielectric layer away from the silicon substrate.
[0011] In an optional embodiment, the doped dielectric layer is a phosphorus-carbon-oxygen-silicon compound.
[0012] In an optional embodiment, the thickness of the doped dielectric layer is less than 5 nm.
[0013] In an optional embodiment, the first doped polysilicon layer, the second doped polysilicon layer and the third doped polysilicon layer are of the same doping type.
[0014] In an optional embodiment, the doping concentration of the third doped polysilicon layer is less than the doping concentration of the first doped polysilicon layer and the second doped polysilicon layer respectively; and the doping concentration of the first doped polysilicon layer and the second doped polysilicon layer is the same.
[0015] In an optional embodiment, the thickness of the first dielectric layer is 1nm-2nm.
[0016] The thickness of the third doped polysilicon layer is 10nm-30nm.
[0017] The thickness of the second dielectric layer is 0.5nm-1nm.
[0018] In an optional embodiment, the thickness of the second doped polysilicon layer is 10nm-30nm.
[0019] In an optional embodiment, the thickness of the first doped polysilicon layer is 50nm-80nm.
[0020] In an optional embodiment, the silicon substrate, the first doped polysilicon layer, the second doped polysilicon layer and the third doped polysilicon layer are all N-type doped; the doping concentration of the first doped polysilicon layer and the second doped polysilicon layer is 1x10 20 cm -3 -7x10 20 cm -3 ; and the doping concentration of the third doped polysilicon layer is 1x10 17 cm -3 -1x10 19 cm -3 .
[0021] In a second aspect, the present application provides a photovoltaic module comprising the solar cell according to any one of the preceding embodiments.
[0022] The solar cell and the photovoltaic module provided by the embodiments of the present application have the following advantages:
[0023] The present application provides a solar cell, comprising a silicon substrate, a passivation contact structure, a first doped polysilicon layer, a doped dielectric layer and a second doped polysilicon layer which are sequentially stacked. The passivation contact structure comprises a first dielectric layer, a third doped polysilicon layer and a second dielectric layer. By arranging the doped dielectric layer in the doped polysilicon layer, the electron mobility can be improved, the passivation effect can be increased, the open circuit voltage and the fill factor can be improved, and thus the photoelectric conversion efficiency can be improved.
[0024] Other features and advantages of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS
[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.
[0026] Figure 1 A schematic diagram of a solar cell in the related art;
[0027] Figure 2 A schematic diagram of a structure of a solar cell in an embodiment of the present application;
[0028] Figure 3 A schematic diagram of a structure of a solar cell in another embodiment of the present application;
[0029] Figure 4 A doping concentration curve of a doped polysilicon layer after annealing deposited by PECVD deposition method.
[0030] Legend: 100-silicon substrate; 200-passivated contact structure; 210-first dielectric layer; 220-third doped polysilicon layer; 230-second dielectric layer; 310-first doped polysilicon layer; 320-doped dielectric layer; 330-second doped polysilicon layer; 400-emitter layer; 510-first anti-reflection layer; 520-second anti-reflection layer; 610-first electrode; 620-second electrode. DETAILED DESCRIPTION
[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.
[0032] In the description of the present application, it should be noted that the positions or location relationships indicated by the terms "inner", "outer" and the like are based on the positions or location relationships shown in the drawings, or the positions or location relationships of the products of the present application when they are usually placed, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements must have a particular position, be constructed and operated in a particular position, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only used for differentiation and description, and cannot be understood as indicating or implying relative importance.
[0033] In the description of the present application, it is also necessary to explain that, unless otherwise explicitly specified and limited, the terms "set", "connected" should be understood broadly, for example, it can be fixedly connected, or detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0034] Tunnel Oxide Passivated Contact (TOPCon) has high photoelectric conversion efficiency and long-term stability. The presence of the tunneling oxide layer allows electrons to pass through the oxide layer by tunneling effect, thereby achieving efficient current transmission. By tunneling through the oxide layer and the doped polysilicon layer, the passivation performance of the cell surface can be improved, the metal contact recombination current can be reduced, and the open circuit voltage and short circuit current of the cell can be effectively improved. Figure 1 is a schematic diagram of a solar cell in the related art. As shown in Figure 1 The solar cell in the related art includes a silicon substrate and a tunnel oxide layer, a lightly doped polysilicon layer, and a heavily doped polysilicon layer deposited on the silicon substrate in sequence. PECVD deposition method (plasma enhanced chemical vapor deposition) has the advantages of fast deposition speed, large output, and in-situ doping compared with LPCVD deposition method (low pressure chemical vapor deposition) and is widely used. In-situ doping can further improve the doping concentration to improve the conductivity and thus improve the cell efficiency. However, too high doping concentration will cause the doping element (such as P) to damage the tunnel oxide layer in the subsequent high-temperature annealing and crystallization process, resulting in passivation failure and thus reducing the photoelectric conversion efficiency.
[0035] To improve the poor passivation effect of the TOPCon cell in the related art, the present application provides a solar cell, which adds a doped dielectric layer in the doped polysilicon layer to improve the passivation effect and improve the photoelectric conversion efficiency of the cell.
[0036] Figure 2 is a structure schematic diagram of a solar cell in an embodiment of the present application. As shown in Figure 2As shown, the solar cell provided by the embodiment of the present application comprises a silicon substrate 100, a passivation contact structure 200, a first doped polysilicon layer 310, a doped dielectric layer 320 and a second doped polysilicon layer 330 which are sequentially stacked. The passivation contact structure 200 is arranged on the surface of the silicon substrate 100, the first doped polysilicon layer 310 is arranged on the surface of the passivation contact structure 200 away from the silicon substrate 100, the doped dielectric layer 320 is arranged on the surface of the first doped polysilicon layer 310 away from the silicon substrate 100, and the second doped polysilicon layer 330 is arranged on the surface of the doped dielectric layer 320 away from the silicon substrate 100. By arranging the doped dielectric layer 320 between the first doped polysilicon layer 310 and the second doped polysilicon layer 330, the field passivation and chemical passivation effects can be increased, thereby improving the efficiency.
[0037] In the embodiment, the thickness of the doped dielectric layer 320 is less than 5 nm. The doped dielectric layer 320 can achieve the field passivation and chemical passivation effects without being too thick, thereby improving the open voltage and fill factor and thus improving the efficiency. In the embodiment, the thickness of the doped dielectric layer 320 is less than 5 nm, which can achieve the corresponding effects without increasing the process cost too much. Further, the thickness of the doped dielectric layer 320 is 2 nm to 4 nm.
[0038] In the embodiment, the doped dielectric layer 320 is a phosphorus-carbon-oxygen-silicon compound. Specifically, the doped dielectric layer 320 comprises phosphorus-doped silicon oxide and phosphorus-doped silicon carbide. The high electron mobility of silicon carbide can strengthen the field passivation effect on the surface of the polysilicon film layer, and the silicon oxide can increase the chemical passivation effect, thereby improving the open voltage and fill factor and thus improving the photoelectric conversion efficiency.
[0039] Further, the atomic ratio of phosphorus to carbon in the doped dielectric layer 320 is 1:1 to 5:1, the atomic ratio of oxygen to silicon is 1:2.5 to 1:15, and the atomic ratio of carbon to oxygen is 1:1.5 to 1:2.5.
[0040] In the embodiment, the passivation contact structure 200 comprises a first dielectric layer 210, a third doped polysilicon layer 220 and a second dielectric layer 230 which are sequentially stacked. The first dielectric layer 210 is connected to the silicon substrate 100, and the second dielectric layer 230 is connected to the first doped polysilicon layer 310. The second dielectric layer 230 can block a part of the high-concentration phosphorus atoms in the first doped polysilicon layer 310 from advancing into the third doped polysilicon layer 220 with low doping concentration during high-temperature annealing, thereby reducing the probability of the phosphorus atoms in the third doped polysilicon layer 220 penetrating through the first dielectric layer 210 and reducing the destructive effect of the phosphorus atoms on the first dielectric layer 210.
[0041] In other optional embodiments, the passivation contact structure 200 can also only include one tunneling oxide layer, such as only including the first dielectric layer 210 and the third doped polysilicon layer 220 in the present embodiment, and omitting the second dielectric layer 230, so that the third doped polysilicon layer 220 is in direct contact with the first doped polysilicon layer 310. In other embodiments, the passivation contact structure 200 can also include more tunneling oxide layers.
[0042] In the present embodiment, the material of the first dielectric layer 210 and the second dielectric layer 230 is SiO x .
[0043] In the present embodiment, the doping concentration of the third doped polysilicon layer 220 is less than the doping concentration of the first doped polysilicon layer 310 and the second doped polysilicon layer 330. In other words, the third doped polysilicon layer 220 is a lightly doped polysilicon layer compared to the first doped polysilicon layer 310 and the second doped polysilicon layer 330, and the first doped polysilicon layer 310 and the second doped polysilicon layer 330 are heavily doped polysilicon layers.
[0044] In the present embodiment, the first doped polysilicon layer 310, the second doped polysilicon layer 330, and the third doped polysilicon layer 220 are all N-type doped. Optionally, the doping element is phosphorus. In other embodiments, the doping element of the first doped polysilicon layer 310, the second doped polysilicon layer 330, and the third doped polysilicon layer 220 can also be arsenic or antimony.
[0045] Further, the doping concentration of the first doped polysilicon layer 310 and the second doped polysilicon layer 330 is 1×10 20 cm -3 ~7×10 20 cm -3 ; and the doping concentration of the third doped polysilicon layer 220 is 1×10 17 cm -3 ~1×10 19 cm -3 .
[0046] Further, in the present embodiment, the thickness of the first doped polysilicon layer 310 is 50nm~80nm, and the thickness of the second doped polysilicon layer 330 is 10nm~30nm.
[0047] Further, the thickness of the first dielectric layer 210 is 1nm~2nm, the thickness of the third doped polysilicon layer 220 is 10nm~30nm, and the thickness of the second dielectric layer 230 is 0.5nm~1nm.
[0048] In the present embodiment, the silicon substrate 100 can be an N-type doped single crystal silicon or a polycrystalline silicon.
[0049] Figure 3 This is a schematic diagram of the structure of a solar cell according to another embodiment of this application. Figure 3 As shown, in Figure 2 Based on the embodiments, the solar cell further includes an emitter layer 400, a first antireflection layer 510, a first electrode 610, a second antireflection layer 520, and a second electrode 620. The emitter layer 400 is disposed on the side of the silicon substrate 100 opposite to the passivation contact structure 200. The first antireflection layer 510 is disposed on the side of the emitter layer 400 opposite to the silicon substrate 100. The first electrode 610 passes through the first antireflection layer 510 and is connected to the emitter layer 400. The second antireflection layer 520 is disposed on the side of the second doped polycrystalline silicon layer 330 opposite to the doped dielectric layer 320. The second electrode 620 passes through the second antireflection layer 520 and is connected to the second doped polycrystalline silicon layer 330. The first antireflection layer 510 and the second antireflection layer 520 can improve light absorption efficiency, thereby improving the overall photoelectric conversion efficiency of the cell. The materials of the first antireflection layer 510 and the second antireflection layer 520 can be silicon nitride, silicon oxide, etc.
[0050] In this embodiment, the first electrode 610 and the second electrode 620 can be manufactured by methods such as screen printing and electroplating.
[0051] In this embodiment, the fabrication of the doped dielectric layer 320 can be performed after the completion of the first doped polycrystalline silicon layer 310. This is achieved by simultaneously ionizing and depositing CO2, silane, phosphine, and hydrogen to form a phosphorus-carbon-oxygen silicon compound with a thickness of less than 5 nm, composed of phosphorus-containing silicon carbide and phosphorus-containing silicon oxide. That is, between the deposition of the first doped polycrystalline silicon layer 310 and the second doped polycrystalline silicon layer 330, additional CO2 is added (because silane, phosphine, and hydrogen are the raw materials required for depositing the doped polycrystalline silicon layer), thereby depositing and forming the phosphorus-carbon-oxygen silicon compound. Figure 4 This is a doping concentration curve of a PECVD-deposited doped polysilicon layer after annealing. The horizontal axis represents the thickness (in μm), with the zero point located on the side of the second doped polysilicon layer 330 furthest from the silicon substrate 100. The vertical axis represents the doping concentration. Figure 4 As shown, after annealing, the doped polycrystalline silicon layer has a high doping concentration at a depth of 20-40 nm, which then decreases rapidly. When the doped polycrystalline silicon layer and the electrode form a contact, the region with the higher doping concentration contributes the most. Therefore, adding CO2 to the 20-40 nm deep doped polycrystalline silicon layer allows for the formation of a phosphorus-carbon-oxygen-silicon compound film (i.e., the doped dielectric layer 320 in this embodiment). On one hand, the phosphorus-containing carbon-silicon compound improves electron mobility, increasing conductivity and field passivation effect; on the other hand, the phosphorus-containing oxygen-silicon compound forms chemical passivation and also prevents phosphorus atom inward diffusion, protecting the tunneling oxide layer. This improves the open-circuit voltage and fill factor, ultimately increasing the photoelectric conversion efficiency.
[0052] Table 1 is a printing test comparison of the solar cell of the embodiment of the present application and the solar cell of the comparative example; and Table 2 is a pilot test comparison of the solar cell of the embodiment of the present application and the solar cell of the comparative example. In the embodiment of the present application, the thickness of the first dielectric layer 210 is 1.4 nm, the thickness of the third doped polysilicon layer 220 is 14 nm, the thickness of the second dielectric layer 230 is 0.7 nm, the thickness of the first doped polysilicon layer 310 is 63 nm, the thickness of the doped dielectric layer 320 is 4 nm, the thickness of the second doped polysilicon layer 330 is 20 nm, and the doping concentration of the first doped polysilicon layer 310 and the second doped polysilicon layer 330 is 1×10 20 cm -3 , and the doping concentration of the third doped polysilicon layer 220 is 5×10 18 cm -3 . The solar cell of the comparative example differs from the solar cell of the embodiment of the present application in that the doped dielectric layer 320 is replaced by the same material as the first doped polysilicon layer 310 and the second doped polysilicon layer 330. The data in the table are converted to show the relative proportions of the two.
[0053] Table 1:
[0054]
[0055] Table 2:
[0056]
[0057] As can be seen from Table 1 and Table 2, the solar cell provided by the embodiment of the present application has a certain degree of improvement in efficiency, open circuit voltage, fill factor and other parameters by adding a doped dielectric layer 320 with a thickness of less than 5 nm.
[0058] The embodiment of the present application also provides a photovoltaic module comprising the solar cell provided by the above-mentioned embodiment of the present application.
[0059] In summary, the present application provides a solar cell and a photovoltaic module. The solar cell provided by the embodiment of the present application comprises a silicon substrate 100, a passivation contact structure 200, a first doped polysilicon layer 310, a doped dielectric layer 320 and a second doped polysilicon layer 330 which are sequentially stacked; wherein the passivation contact structure 200 comprises a first dielectric layer 210, a third doped polysilicon layer 220 and a second dielectric layer 230 which are sequentially stacked, and the first dielectric layer 210 is connected with the silicon substrate 100. By providing the doped dielectric layer 320 in the doped polysilicon layer, the electron mobility can be improved, the passivation effect can be increased, the open circuit voltage and the fill factor can be improved, and thus the photoelectric conversion efficiency can be improved. The photovoltaic module provided by the embodiment of the present application comprises the above-mentioned solar cell.
[0060] It should be noted that the features of the embodiments in the present application can be combined with each other in the case of no conflict.
[0061] The above only is the preferred embodiment of the present application, and is not used to limit the present application, and the present application can have various changes and changes for the person skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A solar cell, characterized in that, include: Silicon substrate; A passivated contact structure is disposed on the surface of the silicon substrate. The passivated contact structure includes a first dielectric layer, a third doped polysilicon layer, and a second dielectric layer stacked sequentially, wherein the first dielectric layer is connected to the silicon substrate. A first doped polysilicon layer is disposed on the surface of the passivated contact structure away from the silicon substrate. A doped dielectric layer, the doped dielectric layer being disposed on the surface of the first doped polysilicon layer facing away from the silicon substrate; and A second doped polysilicon layer is disposed on the surface of the doped dielectric layer opposite to the silicon substrate.
2. The solar cell according to claim 1, characterized in that, The doped dielectric layer is a phosphorus-carbon-oxygen-silicon compound.
3. The solar cell according to claim 1, characterized in that, The thickness of the doped dielectric layer is less than 5 nm.
4. The solar cell according to claim 3, characterized in that, The first doped polysilicon layer, the second doped polysilicon layer, and the third doped polysilicon layer have the same doping type.
5. The solar cell according to claim 4, characterized in that, The doping concentration of the third doped polysilicon layer is less than that of the first doped polysilicon layer and the second doped polysilicon layer, respectively; the doping concentrations of the first doped polysilicon layer and the second doped polysilicon layer are the same.
6. The solar cell according to claim 1, characterized in that, The thickness of the first dielectric layer is 1 nm to 2 nm; The thickness of the third doped polycrystalline silicon layer is 10 nm to 30 nm. The thickness of the second dielectric layer is 0.5 nm to 1 nm.
7. The solar cell according to any one of claims 1-6, characterized in that, The thickness of the second doped polycrystalline silicon layer is 10 nm to 30 nm.
8. The solar cell according to any one of claims 1-6, characterized in that, The thickness of the first doped polycrystalline silicon layer is 50nm~80nm.
9. The solar cell according to any one of claims 1-6, characterized in that, The silicon substrate, the first doped polysilicon layer, the second doped polysilicon layer, and the third doped polysilicon layer are all N-type doped.
10. A photovoltaic module, characterized in that, The solar cell includes any one of claims 1-9.