Solar cell and preparation method and application thereof

Abstract

This application provides a solar cell, its fabrication method, and its application. The solar cell includes a first film layer, a silicon substrate, and a second film layer stacked together. Along the direction from the silicon substrate to the first film layer, the first film layer includes a first emitter layer and a first electrode layer stacked sequentially. The first emitter layer is connected to the surface of the silicon substrate, and the crystallinity of the first emitter layer near the first electrode layer is greater than that of the side of the first emitter layer near the silicon substrate. And / or along the direction from the silicon substrate to the second film layer, the second film layer includes a second emitter layer and a second electrode layer stacked sequentially. The second emitter layer is connected to the surface of the silicon substrate, and the crystallinity of the second emitter layer near the second electrode layer is greater than that of the side of the second emitter layer near the silicon substrate. The first emitter layer has a first dopant element, the second emitter layer has a second dopant element, and the silicon substrate has either the first dopant element or the second dopant element, wherein the first dopant element and the second dopant element are different.

Description

Technical Field

[0001] This application relates to the field of batteries, specifically to solar cells, their preparation methods, and applications. Background Technology

[0002] Solar cells have attracted widespread attention due to their advantages such as high turn-on voltage, high bifaciality, good conversion efficiency, and simple manufacturing process. However, in the fabrication of solar cells, the addition of doping elements can affect the crystal quality of the film layers, making them prone to cracking and impacting the photoelectric performance of the solar cell. Therefore, there is a need to develop a solar cell with high structural reliability and high photoelectric conversion efficiency. Summary of the Invention

[0003] In view of this, this application provides a solar cell, its preparation method and application. The solar cell has suitable crystal quality of film layers, low probability of film bursting, and high overall structural reliability. At the same time, each film layer in the solar cell has a strong ability to collect charge carriers, which can improve the photoelectric performance of the solar cell, increase the photoelectric conversion efficiency of the solar cell, and facilitate the widespread application of solar cells.

[0004] In a first aspect, this application provides a solar cell, the solar cell comprising a silicon substrate, a first film layer disposed on the surface of the silicon substrate, and a second film layer disposed on a side surface of the silicon substrate opposite to the first film layer;

[0005] Along the direction from the silicon substrate to the first film layer, the first film layer includes a first emitter layer and a first electrode layer stacked together. The first emitter layer is connected to the surface of the silicon substrate, and the crystallinity of the first emitter layer near the first electrode layer is greater than the crystallinity of the first emitter layer near the silicon substrate; and / or

[0006] Along the direction from the silicon substrate to the second film layer, the second film layer includes a second emitter layer and a second electrode layer stacked thereon, the second emitter layer being connected to the surface of the silicon substrate, and the crystallinity of the second emitter layer on the side closer to the second electrode layer being greater than the crystallinity of the second emitter layer on the side closer to the silicon substrate.

[0007] The first emitter layer has a first doping element, the second emitter layer has a second doping element, and the silicon substrate has either the first doping element or the second doping element, wherein the first doping element and the second doping element are different.

[0008] Optionally, along the direction from the silicon substrate to the first film layer, the first emitter layer includes a first seed layer and a first emitter body layer sequentially stacked, the first seed layer being connected to the surface of the silicon substrate, the first emitter body layer being connected to the first electrode layer, the crystallinity of the first seed layer being 0.3-0.6, and the crystallinity of the first emitter body layer being greater than that of the first seed layer; and / or

[0009] Along the direction from the silicon substrate to the second film layer, the second emitter layer includes a second seed layer and a second emitter body layer stacked sequentially. The second seed layer is connected to the surface of the silicon substrate, and the second emitter body layer is connected to the second electrode layer. The crystallinity of the second seed layer is 0.3-0.6, and the crystallinity of the second emitter body layer is greater than that of the second seed layer.

[0010] Optionally, the crystallinity of the first emission layer is 0.4-0.7.

[0011] Optionally, the material of the first seed layer includes at least one of microcrystalline silicon containing the first doping element, microcrystalline silicon carbide containing the first doping element, and microcrystalline silicon oxide containing the first doping element.

[0012] Optionally, the material of the first emission layer includes at least one of microcrystalline silicon containing the first doping element, microcrystalline silicon carbide containing the first doping element, and microcrystalline silicon oxide containing the first doping element.

[0013] Optionally, the crystallinity of the second emission layer is 0.4-0.7.

[0014] Optionally, the material of the second seed layer includes at least one of microcrystalline silicon, microcrystalline silicon oxide, microcrystalline silicon carbide, microcrystalline silicon containing the second dopant element, microcrystalline silicon carbide containing the second dopant element, and microcrystalline silicon oxide containing the second dopant element.

[0015] Optionally, the material of the second emission layer includes at least one of microcrystalline silicon containing the second doping element, microcrystalline silicon carbide containing the second doping element, and microcrystalline silicon oxide containing the second doping element.

[0016] Optionally, when the second seed layer has the second dopant element, the molar ratio of the second dopant element to silicon in the second seed layer is greater than the molar ratio of the first dopant element to silicon in the first seed layer.

[0017] Optionally, the molar ratio of the first dopant element to silicon in the first emitter layer is greater than the molar ratio of the first dopant element to silicon in the first seed layer.

[0018] Optionally, a first passivation layer may be further included between the silicon substrate and the first emitter layer, and / or a second passivation layer may be further included between the silicon substrate and the second emitter layer.

[0019] Optionally, the material of the first passivation layer includes at least one of amorphous silicon, amorphous silicon oxide, and silicon carbide, and the material of the second passivation layer includes at least one of amorphous silicon, amorphous silicon oxide, and silicon carbide.

[0020] Optionally, the first film layer further includes a first transition layer disposed between the first emitter layer and the first electrode layer.

[0021] Optionally, the material of the first transition layer includes at least one of microcrystalline silicon containing the first dopant element, microcrystalline silicon oxide containing the first dopant element, and microcrystalline silicon carbide containing the first dopant element.

[0022] Optionally, the second film layer further includes a second transition layer disposed between the second emitter layer and the second electrode layer.

[0023] Optionally, the second film layer further includes a second transition layer and a buffer layer disposed between the second emission layer and the second electrode layer, wherein the second transition layer is disposed between the second emission layer and the buffer layer.

[0024] Optionally, the material of the second transition layer includes at least one of microcrystalline silicon containing the second doping element, microcrystalline silicon oxide containing the second doping element, and microcrystalline silicon carbide containing the second doping element.

[0025] Optionally, the second film layer further includes a buffer layer disposed between the second emitter layer and the second electrode layer.

[0026] Optionally, the material of the buffer layer includes at least one of amorphous silicon containing the second doping element and amorphous silicon oxide containing the second doping element.

[0027] Optionally, when the second seed layer has the second dopant element, the molar ratio of the second dopant element to silicon in the second seed layer is greater than the molar ratio of the first dopant element to silicon in the first seed layer.

[0028] Optionally, the molar ratio of the first dopant element to silicon in the first emitter layer is greater than the molar ratio of the first dopant element to silicon in the first seed layer.

[0029] Optionally, the photoelectric conversion efficiency of the solar cell is greater than 25%.

[0030] The crystallinity variation in the first and / or second emitter layers of the solar cell provided in this application results in a higher matching between the silicon substrate, the first emitter layer and the first electrode, and / or the silicon substrate, the second emitter layer and the second electrode film. This effectively avoids film bursting, improves the structural stability of the solar cell, and enhances the carrier collection capability, thereby improving the photoelectric conversion efficiency of the solar cell and facilitating its widespread application.

[0031] Secondly, this application provides a method for preparing a solar cell, comprising:

[0032] A first film layer and a second film layer are deposited on a silicon substrate to obtain a solar cell. The solar cell includes a silicon substrate, a first film layer disposed on the surface of the silicon substrate, and a second film layer disposed on a side of the silicon substrate opposite to the first film layer. Along the direction from the silicon substrate to the first film layer, the first film layer includes a first emitter layer and a first electrode layer stacked sequentially. The first emitter layer is connected to the surface of the silicon substrate, and the crystallinity of the first emitter layer near the first electrode layer is greater than the crystallinity of the first emitter layer near the silicon substrate. And / or along the direction from the silicon substrate to the second film layer, the second film layer includes a second emitter layer and a second electrode layer stacked sequentially. The second emitter layer is connected to the surface of the silicon substrate, and the crystallinity of the second emitter layer near the second electrode layer is greater than the crystallinity of the second emitter layer near the silicon substrate. The first emitter layer has a first dopant element, the second emitter layer has a second dopant element, and the silicon substrate has either the first dopant element or the second dopant element, wherein the first dopant element and the second dopant element are different.

[0033] Optionally, carbon dioxide plasma treatment may be included before preparing the first emission layer and / or the second emission layer.

[0034] Optionally, the carbon dioxide flow rate in the carbon dioxide plasma treatment is 50 sccm-200 sccm, the treatment time is 5 s-15 s, and the power is 66 W / m³. 2 -200W / m 2 .

[0035] The method for preparing solar cells provided in this application is novel and the preparation process is simple, which can produce solar cells with excellent overall performance.

[0036] Thirdly, this application provides a solar cell, which includes the solar cell described in the first aspect or the solar cell prepared by the preparation method described in the second aspect.

[0037] The solar cell provided in this application has high photoelectric conversion efficiency and excellent safety in use, which is conducive to improving the application of solar cells.

[0038] Fourthly, this application provides an electrical device that includes the solar cell described in the third aspect.

[0039] The electrical equipment provided in this application has excellent overall performance, high photoelectric utilization rate, and strong product competitiveness. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0041] Figure 1 This is a cross-sectional schematic diagram of a solar cell provided in one embodiment of this application.

[0042] Figure 2 This is a cross-sectional schematic diagram of a solar cell provided for another embodiment of this application.

[0043] Figure 3 This is a cross-sectional schematic diagram of a solar cell provided in another embodiment of this application.

[0044] Figure 4 This is a cross-sectional schematic diagram of a solar cell provided in another embodiment of this application.

[0045] Figure 5 This is a cross-sectional schematic diagram of a solar cell provided in another embodiment of this application.

[0046] Figure 6 This is a cross-sectional schematic diagram of a solar cell provided in another embodiment of this application.

[0047] Figure 7 This is a cross-sectional schematic diagram of a solar cell provided in another embodiment of this application.

[0048] Figure 8 This is a flowchart illustrating the fabrication process of a solar cell according to one embodiment of this application.

[0049] Figure 9 A flowchart illustrating the fabrication process of a solar cell according to another embodiment of this application.

[0050] Figure 10 A flowchart illustrating the fabrication process of a solar cell according to another embodiment of this application.

[0051] Figure 11A flowchart illustrating the fabrication process of a solar cell according to another embodiment of this application.

[0052] Figure 12 A flowchart illustrating the fabrication process of a solar cell according to another embodiment of this application.

[0053] Figure 13 This is a surface morphology diagram of the solar cell after coating provided in Embodiment 1 of this application.

[0054] Figure 14 This is a surface morphology diagram of the solar cell after coating provided in Comparative Example 1 of this application. Detailed Implementation

[0055] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0056] Please see Figure 1This is a cross-sectional schematic diagram of a solar cell 100 provided in one embodiment of this application. The solar cell 100 includes a silicon substrate 10, a first film layer 20 disposed on the surface of the silicon substrate 10, and a second film layer 30 disposed on the side of the silicon substrate 10 facing away from the first film layer 20. Along the direction from the silicon substrate 10 to the first film layer 20, the first film layer 20 includes a first emitting layer 23' and a first electrode layer 24 stacked together. The first emitting layer 23' is connected to the surface of the silicon substrate 10, and the crystallinity of the side of the first emitting layer 23' closer to the first electrode layer 24 is greater than that of the side of the first emitting layer 23' closer to the silicon substrate 10. The crystallinity on one side; and / or along the direction from the silicon substrate 10 to the second film layer 30, the second film layer 30 includes a second emitter layer 33' and a second electrode layer 34 stacked sequentially, the second emitter layer 33' being connected to the surface of the silicon substrate 10, the crystallinity of the second emitter layer 33' near the second electrode layer 34 being greater than the crystallinity of the second emitter layer 33' near the silicon substrate 10; the first emitter layer 23' having a first doped element, the second emitter layer 33' having a second doped element, the silicon substrate 10 having either a first doped element or a second doped element, the first doped element being different from the second doped element. The silicon substrate serves as a light-absorbing region, enhancing the light absorption efficiency of the solar cell. In the direction from the silicon substrate to the first or second film layer, the crystallinity of the first emitter layer near the first electrode layer is greater than that near the silicon substrate, and the crystallinity of the second emitter layer near the second electrode layer is greater than that near the silicon substrate. This mitigates the surge of hydrogen atoms caused by the significant increase in crystallinity, reduces film stress generated by hydrogen atoms, and minimizes the occurrence of film bursting, thus improving the structural stability, lifespan, and photoelectric conversion efficiency of the solar cell. The first and second electrode layers enhance the conductivity of the solar cell, enabling high-efficiency photoelectric conversion. Therefore, the solar cell provided in this application exhibits good structural stability and high photoelectric conversion efficiency, which is beneficial for its use.

[0057] In this application, the silicon substrate is the light-absorbing region, which can enhance the light absorption efficiency of the solar cell. In some embodiments, the silicon substrate can be made of monocrystalline silicon.

[0058] In this application, the silicon substrate and the first emitter layer have a first doping element, and the second emitter layer has a second doping element; one of the first and second doping elements can be boron, and the other can be phosphorus. In one embodiment of this application, the silicon substrate and the first emitter layer have the first doping element, which is a first doping type; the second emitter layer has the second doping element, which is a second doping type; the first doping type and the second doping type are different. Specifically, one of the first and second doping types is N-type doping, and the other is P-type doping; where N-type doping refers to semiconductor materials with N-type doping for electron transport, such as phosphorus doping, and P-type doping refers to semiconductor materials with P-type doping for hole transport, such as boron doping. In this application, the silicon substrate is the light absorption region, which improves the light absorption rate of the solar cell, provides support and growth environment for the subsequent film layer, and forms a heterojunction with the film layer to realize the photoelectric conversion of the solar cell. The different first doping elements make the silicon substrate a different type of substrate. Specifically, the silicon substrate can be, but is not limited to, an N-type silicon substrate or a P-type silicon substrate. In one embodiment of this application, the silicon substrate can be an N-type silicon substrate, which can improve the photoelectric conversion efficiency of the solar cell. In this case, the first doping element in the silicon substrate is phosphorus. In another embodiment of this application, the silicon substrate is an N-type silicon substrate, the first film layer is the light-receiving surface, the first doping type is N-type doping, and the first doping element is phosphorus; the second film layer is the back-lighting surface, the second doping type is P-type doping, and the second doping element is boron. In another embodiment of this application, the silicon substrate is a P-type silicon substrate, the first film layer is the light-receiving surface, the first doping type is P-type doping, and the first doping element is boron; the second film layer is the back-lighting surface, the second doping type is N-type doping, and the second doping element is phosphorus.

[0059] In this application, crystallinity reflects the ratio of crystalline to amorphous states in the film. A higher crystallinity indicates more complete crystallization and a greater amount of crystalline components, while a lower crystallinity indicates a higher amorphous content. Crystallinity can be measured using a Raman spectrometer. Gaussian three-peak fitting is performed on the Raman spectrum of the thin film to obtain the crystallinity Xc. The crystallinity Xc is calculated using the following formula:

[0060]

[0061] Among them, I c It is crystalline silicon, I g For crystalline silicon grain boundaries, I a It is amorphous silicon, I 516.4 The spectral peak positions of crystalline silicon, I 507.4 The spectral peak position of crystalline silicon grain boundaries, I 485.3 These represent the spectral peak positions of amorphous silicon.

[0062] In this application, crystalline silicon generally exists in a microcrystalline structure. Microcrystalline refers to a mixed state of amorphous and polycrystalline / single-crystal, which is a mixed-phase disordered material between amorphous and polycrystalline / single-crystal, with grain size typically ranging from tens to hundreds of nanometers. Among them, amorphous is a grainless state, while polycrystalline / single-crystal is composed entirely of crystal particles separated by grain boundaries. The higher the crystallinity, the closer the state is to polycrystalline / single-crystal; the lower the crystallinity, the closer it is to amorphous.

[0063] Please see Figure 2 This is a cross-sectional schematic diagram of a solar cell provided in another embodiment of this application. The first emitting layer 23' includes a first seed layer 22 and a first emitting layer 23 stacked sequentially. The first seed layer 22 is connected to the surface of the silicon substrate 10, and the first emitting layer 23 is connected to the first electrode layer 24. The crystallinity of the first seed layer 22 is 0.3-0.6, and the crystallinity of the first emitting layer 23 is equal to the crystallinity of the first seed layer 22. Controlling the crystallinity of the first seed layer between 0.3 and 0.6 reduces the occurrence of film bursting, which is beneficial to improving the structural stability, lifespan, and photoelectric conversion efficiency of the solar cell. The crystallinity of the first emitting layer is greater than that of the first seed layer. The more microcrystalline structures in the solar cell, the higher the light transmittance and carrier mobility, which can improve the carrier transport capacity and photoelectric conversion efficiency. In some embodiments, when using hydrogen passivation, the more crystalline structures, the more obvious the hydrogen passivation effect, thereby further improving the carrier transport capacity and photoelectric conversion efficiency.

[0064] Please see Figure 3 This is a cross-sectional schematic diagram of a solar cell provided in another embodiment of this application. A first passivation layer 21 is further included between the silicon substrate 10 and the first emitter layer 23'. In one embodiment of this application, the first passivation layer can be disposed between the first seed layer and the silicon substrate. The first passivation layer can reduce the impact of interface defects on cell performance and improve the stability of the solar cell.

[0065] In this application, the first seed layer provides stable growth conditions for subsequent film layers, ensuring the structural stability of the solar cell. In one embodiment of this application, the first passivation layer can reduce the impact of interface defects and improve cell efficiency and stability. In one embodiment of this application, the material of the first passivation layer includes at least one of amorphous silicon, amorphous silicon oxide, and silicon carbide. In one embodiment of this application, the material of the first passivation layer can be amorphous silicon. In another embodiment of this application, the material of the first passivation layer can be silicon carbide. In one embodiment of this application, the thickness of the first passivation layer is 7nm-10nm; a thinner first passivation layer can improve the carrier transport speed. Specifically, the thickness of the first passivation layer can be, but is not limited to, 7nm, 7.5nm, 8nm, 8.5nm, 9nm, 9.5nm, or 10nm. In one embodiment of this application, the thickness of the first passivation layer can be 7nm-8.5nm. In another embodiment of this application, the thickness of the first passivation layer can be 8nm-10nm.

[0066] In one embodiment of this application, the crystallinity of the first seed layer is 0.3-0.6, which can reduce the generation of impurity defects and film bursting, thereby avoiding the phenomenon of carrier recombination in deep energy levels and reduction of the number of carriers due to impurity defects, improving the open-circuit voltage and short-circuit current of the solar cell, and enhancing the photoelectric conversion efficiency of the solar cell. Specifically, the crystallinity of the first seed layer can be, but is not limited to, 0.3, 0.35, 0.4, 0.45, 0.5, 0.5, or 0.6. In one embodiment of this application, the crystallinity of the first seed layer can be 0.3-0.56. In another embodiment of this application, the crystallinity of the first seed layer can be 0.5-0.6.

[0067] In one embodiment of this application, the material of the first seed layer includes at least one of microcrystalline silicon containing a first dopant element, microcrystalline silicon carbide containing a first dopant element, and microcrystalline silicon oxide containing a first dopant element. In one embodiment of this application, the material of the first seed layer can be microcrystalline silicon containing a first dopant element. In another embodiment of this application, the material of the first seed layer can be microcrystalline silicon oxide containing a first dopant element. In one embodiment of this application, the thickness of the first seed layer is 3nm-5nm. Specifically, the thickness of the first seed layer can be, but is not limited to, 3nm, 3.5nm, 4nm, 4.2nm, 4.5nm, 4.8nm, or 5nm. In one embodiment of this application, the thickness of the first seed layer can be 3nm-4.5nm.

[0068] In one embodiment of this application, the molar ratio of the first dopant element to silicon in the first seed layer is 1:(20-25). Specifically, the molar ratio of the first dopant element to silicon in the first seed layer can be, but is not limited to, 1:20, 1:21, 1:22, 1:23, 1:24, or 1:25. In one embodiment of this application, the molar ratio of the first dopant element to silicon in the first seed layer can be 1:(20-23). ​​In another embodiment of this application, the molar ratio of the first dopant element to silicon in the first seed layer can be 1:(22-25).

[0069] In this application, the crystallinity of the first emitter layer is greater than that of the first seed layer. A higher crystallinity in the first emitter layer improves conductivity and carrier mobility, while a lower crystallinity in the first seed layer reduces impurities and defects generated during subsequent coating processes, preventing carrier recombination at deeper energy levels within defects and improving the open-circuit voltage and short-circuit current of the solar cell. Simultaneously, a higher crystallinity results in higher hydrogen content, a denser film structure, and greater stress generated by hydrogen atoms. The first seed layer acts as a transition between the first passivation layer and the first emitter layer, balancing the process matching between the amorphous first passivation layer and the high-crystallinity first emitter layer. This mitigates the surge in hydrogen content and increased film stress caused by the increased crystallinity, reducing the risk of film bursting in the solar cell. In one embodiment of this application, the crystallinity of the first emitter layer is 0.4-0.7, balancing the optical and electrical properties of the solar cell. This improves both the process matching between the upper and lower layers of the first emitter layer and enhances conductivity and carrier mobility, thereby increasing the photoelectric conversion efficiency of the solar cell. Specifically, the crystallinity of the first emission layer can be, but is not limited to, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, or 0.7. In one embodiment of this application, the crystallinity of the first emission layer can be 0.4-0.55. In another embodiment of this application, the crystallinity of the first emission layer can be 0.5-0.7.

[0070] In one embodiment of this application, the material of the first emission layer includes at least one of microcrystalline silicon containing a first dopant element, microcrystalline silicon carbide containing a first dopant element, and microcrystalline silicon oxide containing a first dopant element. In one embodiment of this application, the material of the first emission layer can be microcrystalline silicon oxide containing a first dopant element. Microcrystalline silicon oxide has a wide band gap and a broad absorption spectrum, allowing it to absorb photons across a wider spectrum and thus generate more charge carriers. In another embodiment of this application, the material of the first emission layer can be microcrystalline silicon containing a first dopant element. In one embodiment of this application, the thickness of the first emission layer is 15nm-20nm. Specifically, the thickness of the first emission layer can be, but is not limited to, 15nm, 16nm, 17nm, 18nm, 19nm, or 20nm. In one embodiment of this application, the thickness of the first emission layer can be 15nm-18nm. In another embodiment of this application, the thickness of the first emission layer can be 17nm-20nm.

[0071] In one embodiment of this application, the molar ratio of the first dopant element to silicon in the first emitter layer is 1:(16-19). Specifically, the molar ratio of the first dopant element to silicon in the first emitter layer can be, but is not limited to, 1:16, 1:17, 1:18, or 1:19. In one embodiment of this application, the molar ratio of the first dopant element to silicon in the first emitter layer can be 1:(16-18). In another embodiment of this application, the molar ratio of the first dopant element to silicon in the first emitter layer can be 1:(17-19).

[0072] In one embodiment of this application, the molar ratio of the first dopant element to silicon in the first emitter layer is greater than that in the first seed layer. A concentration gradient of the first dopant element is formed between the first emitter layer and the first seed layer, which can improve carrier mobility and cause more carriers to move along the direction of increasing concentration gradient (i.e., the electrode direction), thereby increasing the short-circuit current of the solar cell. Please refer to [link to relevant documentation]. Figure 4This is a cross-sectional schematic diagram of a solar cell provided in another embodiment of this application, wherein the first film layer 20 further includes a first transition layer 25 disposed between the first emitter layer 23 and the first electrode layer 24. The first transition layer can increase the number of charge carriers and improve the photoelectric conversion efficiency. In one embodiment of this application, the material of the first transition layer includes at least one of microcrystalline silicon containing a first dopant element, microcrystalline silicon oxide containing a first dopant element, and microcrystalline silicon carbide containing the first dopant element. In one embodiment of this application, the material of the first transition layer can be microcrystalline silicon containing a first dopant element. In one embodiment of this application, the thickness of the first transition layer is 1nm-2nm. Specifically, the thickness of the first transition layer can be, but is not limited to, 1nm, 1.2nm, 1.3nm, 1.5nm, 1.7nm, 1.9nm, or 2nm. In one embodiment of this application, the thickness of the first transition layer can be 1nm-1.6nm. In another embodiment of this application, the thickness of the first transition layer can be 1.4nm-2nm.

[0073] In one embodiment of this application, the molar ratio of the first dopant element to silicon in the first transition layer is 1:(10-16). Specifically, the molar ratio of the first dopant element to silicon in the first transition layer can be, but is not limited to, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, or 1:16. In one embodiment of this application, the molar ratio of the first dopant element to silicon in the first transition layer can be 1:(10-14). In one embodiment of this application, the molar ratio of the first dopant element to silicon in the first transition layer can be 1:(12-16).

[0074] In one embodiment of this application, the molar ratio of the first dopant element to silicon increases sequentially in the first seed layer, the first emitter layer, and the first transition layer. This creates a larger concentration gradient of the first dopant element within the first film layer, resulting in a more efficient carrier concentration gradient. This improves gradient guidance for hole transport, enhances hole carrier collection capability, and makes it easier for carriers to be absorbed by the outer first electrode layer, increasing short-circuit current and further improving photoelectric conversion efficiency.

[0075] Please see Figure 5This is a cross-sectional schematic diagram of a solar cell provided in another embodiment of this application, wherein the first electrode layer 24 includes a first transparent conductive layer 241 and a first metal electrode 242, and the first transparent conductive layer 241 is disposed between the first emitting layer 23 and the first metal electrode 242. The first transparent conductive layer has good optical transmittance and conductivity, which can improve the light utilization rate of the solar cell and enhance the photoelectric conversion efficiency of the solar cell. In one embodiment of this application, the material of the first metal electrode may include, but is not limited to, at least one of gold, silver and copper. In one embodiment of this application, the material of the first metal electrode may be silver. In one embodiment of this application, the first transparent conductive layer may include, but is not limited to, at least one of ITO (indium tin oxide), AZO (zinc aluminum oxide) and IZO (indium zinc oxide). In one embodiment of this application, the first transparent conductive layer may be ITO (indium tin oxide).

[0076] In one embodiment of this application, the thickness of the first transparent conductive layer is 90nm-110nm, which can improve light utilization. Specifically, the thickness of the first transparent conductive layer can be, but is not limited to, 90nm, 95nm, 100nm, 102nm, 105nm, or 110nm. In one embodiment of this application, the thickness of the first transparent conductive layer can be 90nm-108nm. In another embodiment of this application, the thickness of the first transparent conductive layer can be 100nm-110nm.

[0077] In one embodiment of this application, please refer to Figure 2 The second emitter layer 33' comprises a second seed layer 32 and a second emitter layer 33 stacked sequentially. The second seed layer 32 is connected to the surface of the silicon substrate 10, and the second emitter layer 33 is connected to the second electrode layer 34. The crystallinity of the second seed layer 32 is 0.3-0.6, and the crystallinity of the second emitter layer 33 is 0.4-0.7, with the crystallinity of the second emitter layer 33 being greater than that of the second seed layer 32. Controlling the crystallinity of the second seed layer between 0.3 and 0.6 reduces the occurrence of film bursting, which is beneficial for improving the structural stability, lifespan, and photoelectric conversion efficiency of the solar cell. A higher crystallinity of the second emitter layer compared to the second seed layer means that the more microcrystalline structures in the solar cell, the better the carrier transport capacity and photoelectric conversion efficiency. In some embodiments, when using hydrogen passivation, the more crystalline structures, the more pronounced the hydrogen passivation effect, thereby further improving the carrier transport capacity and photoelectric conversion efficiency.

[0078] In one embodiment of this application, please refer to Figure 3The second passivation layer 31 is further included between the silicon substrate 10 and the second emitter layer 33'. In one embodiment of this application, the second passivation layer can be disposed between the second seed layer and the silicon substrate. The second passivation layer can reduce the impact of interface defects on the cell performance and improve the stability of the solar cell.

[0079] In one embodiment of this application, the material of the second passivation layer includes at least one of amorphous silicon, amorphous silicon oxide, and silicon carbide. In one embodiment of this application, the material of the second passivation layer can be amorphous silicon. In another embodiment of this application, the material of the second passivation layer can be silicon carbide. In one embodiment of this application, the thickness of the second passivation layer is 10nm-15nm. Specifically, the thickness of the second passivation layer can be, but is not limited to, 10nm, 10.5nm, 11nm, 11.5nm, 12nm, 13nm, 14nm, or 15nm. In one embodiment of this application, the thickness of the second passivation layer can be 10nm-13.5nm. In another embodiment of this application, the thickness of the second passivation layer can be 12nm-15nm.

[0080] In this application, the second seed layer provides stable growth conditions for subsequent film layers. In one embodiment of this application, the material of the second seed layer includes at least one of microcrystalline silicon, microcrystalline silicon oxide, microcrystalline silicon carbide, microcrystalline silicon containing a second dopant element, microcrystalline silicon carbide containing a second dopant element, and microcrystalline silicon oxide containing a second dopant element. In one embodiment of this application, the second seed layer is microcrystalline silicon containing a second dopant element, and the second dopant element is boron. The second seed layer may contain a large number of stable boron-silicon chemical bonds, which are not easily decomposed by light, avoiding carrier recombination and reducing photoelectric conversion efficiency. In another embodiment of this application, the second seed layer may also contain silicon-hydrogen chemical bonds and boron-oxide chemical bonds. The boron-oxide chemical bonds can prevent the crystallization formation of the subsequent second film layer. In another embodiment of this application, the material of the second seed layer can be microcrystalline silicon. In this case, the second seed layer is in an intrinsic state, which can reduce the growth rate of the subsequent film layer, reduce the number of structural defects in the subsequent second film layer growth process, avoid carrier recombination with defects, and reduce the number of carriers.

[0081] In one embodiment of this application, the crystallinity of the second seed layer is 0.3-0.6, which can reduce the generation of film bursting and impurity defects, increase the number of charge carriers, improve the open-circuit voltage and short-circuit current of the solar cell, and further improve the photoelectric conversion efficiency of the solar cell. Specifically, the crystallinity of the second seed layer can be, but is not limited to, 0.3, 0.35, 0.4, 0.45, 0.5, 0.5, or 0.6. In one embodiment of this application, the crystallinity of the second seed layer can be 0.3-0.55. In another embodiment of this application, the crystallinity of the second seed layer can be 0.44-0.6. In one embodiment of this application, the thickness of the second seed layer is 1nm-3nm. Specifically, the thickness of the second seed layer can be, but is not limited to, 1nm, 1.5nm, 2nm, 2.2nm, 2.5nm, 2.8nm, or 3nm. In one embodiment of this application, the thickness of the second seed layer can be 1nm-2nm. In another embodiment of this application, the thickness of the second seed layer can be 1.5nm-3nm.

[0082] In one embodiment of this application, when the second seed layer has a second dopant element, the molar ratio of the second dopant element to silicon in the second seed layer is 1:(13-14). A higher molar ratio of the second dopant element to silicon in the second seed layer is beneficial for improving the stability of the boron-oxygen bonds in the second emitter layer. Specifically, the molar ratio of the second dopant element to silicon in the second seed layer can be, but is not limited to, 1:13, 1:13.2, 1:13.5, 1:13.6, 1:13.8, 1:13.9, or 1:14. In one embodiment of this application, the molar ratio of the second dopant element to silicon in the second seed layer can be 1:(13-13.6). In another embodiment of this application, the molar ratio of the second dopant element to silicon in the second seed layer can be 1:(13.4-14).

[0083] In one embodiment of this application, when the second seed layer has a second dopant element, the molar ratio of the second dopant element to silicon in the second seed layer is greater than the molar ratio of the first dopant element to silicon in the first seed layer. That is, the content of the dopant element in the second seed layer is greater than the content of the dopant element in the first seed layer, which helps to reduce the occurrence of film bursting and improve the structural stability of the solar cell.

[0084] In one embodiment of this application, the crystallinity of the second emitter layer is greater than that of the second seed layer. The higher crystallinity of the second emitter layer can improve conductivity and carrier mobility, while the lower crystallinity of the second seed layer can reduce impurities and defects generated during subsequent coating processes, reduce carrier recombination at deeper energy levels of defects, and improve the open-circuit voltage and short-circuit current of the solar cell. Simultaneously, the second seed layer acts as a transition between the second passivation layer and the second emitter layer, balancing the process matching between the amorphous second passivation layer and the high-crystallinity second emitter layer, and reducing the risk of film bursting in the solar cell. In one embodiment of this application, the crystallinity of the second emitter layer is 0.4-0.7, which can improve the photoelectric conversion efficiency of the solar cell. Specifically, the crystallinity of the second emitter layer can be, but is not limited to, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, or 0.7. In one embodiment of this application, the crystallinity of the second emitter layer can be 0.4-0.55. In another embodiment of this application, the crystallinity of the second emission layer can be 0.5-0.7.

[0085] In one embodiment of this application, the material of the second emitter layer includes at least one of microcrystalline silicon containing a second dopant element, microcrystalline silicon carbide containing a second dopant element, and microcrystalline silicon oxide containing a second dopant element. In another embodiment, the material of the second emitter layer can be microcrystalline silicon containing a second dopant element, which reduces the number of lattice defects, increases the number of charge carriers, improves the transport speed of charge carriers (holes), promotes the movement of charge carriers towards the electrode, and improves the photoelectric conversion efficiency of the solar cell. In another embodiment, the thickness of the second emitter layer is 20nm-25nm. Specifically, the thickness of the second emitter layer can be, but is not limited to, 20nm, 21nm, 22nm, 22.5nm, 23nm, 24nm, or 25nm. In one embodiment, the thickness of the second emitter layer can be 20nm-24nm. In another embodiment, the thickness of the second emitter layer can be 23nm-25nm.

[0086] In one embodiment of this application, the molar ratio of the second dopant element to silicon in the second emitter layer is 1:(200-300). Specifically, the molar ratio of the second dopant element to silicon in the second emitter layer can be, but is not limited to, 1:200, 1:220, 1:240, 1:260, 1:280, or 1:300. In one embodiment of this application, the molar ratio of the second dopant element to silicon in the second emitter layer can be 1:(200-270). In another embodiment of this application, the molar ratio of the second dopant element to silicon in the second emitter layer can be 1:(240-300).

[0087] In one embodiment of this application, the molar ratio of the second dopant element to silicon in the second emitter layer is greater than that in the second seed layer. A concentration gradient of the second dopant element is formed between the second emitter layer and the second seed layer, which can promote carrier collection efficiency, accelerate carrier movement, and increase the short-circuit current of the solar cell.

[0088] In one embodiment of this application, please refer to Figure 4 The second film layer 30 further includes a second transition layer 35 disposed between the second emitter layer 33 and the second electrode layer 34. The second transition layer can improve the hole carrier collection capability and enhance the carrier transport efficiency. In one embodiment of this application, the material of the second transition layer includes at least one of microcrystalline silicon containing a second doping element, microcrystalline silicon oxide containing a second doping element, and microcrystalline silicon carbide containing a second doping element. In one embodiment of this application, the material of the second transition layer can be microcrystalline silicon containing a second doping element, providing gradient guidance for hole transport and improving the hole carrier collection capability. In one embodiment of this application, the material of the second transition layer can be microcrystalline silicon oxide containing a second doping element. In one embodiment of this application, the thickness of the second transition layer is 5nm-6nm. Specifically, the thickness of the second transition layer can be, but is not limited to, 5nm, 5.2nm, 5.4nm, 5.6nm, 5.8nm, or 6nm. In one embodiment of this application, the thickness of the second transition layer can be 5nm-5.6nm. In another embodiment of this application, the thickness of the second transition layer can be 5.2nm-6nm.

[0089] In one embodiment of this application, the molar ratio of the second dopant element to silicon in the second transition layer is 1:(30-200). Specifically, the molar ratio of the second dopant element to silicon in the second transition layer can be, but is not limited to, 1:30, 1:50, 1:80, 1:100, 1:130, 1:150, 1:180, or 1:200. In one embodiment of this application, the molar ratio of the second dopant element to silicon in the second transition layer can be 1:(30-120). In another embodiment of this application, the molar ratio of the second dopant element to silicon in the second transition layer can be 1:(100-200).

[0090] In one embodiment of this application, the molar ratio of the second dopant element to silicon in the second transition layer is greater than that in the second emitter layer. In the second film layer, as the molar ratio of the dopant element to silicon gradually increases, a concentration gradient difference of the second dopant element is formed between the second transition layer and the second emitter layer. This improves gradient guidance for hole transport, enhances hole carrier collection capability, and improves the photoelectric conversion efficiency of the solar cell.

[0091] In one embodiment of this application, please refer to Figure 5 The second electrode layer 34 includes a second transparent conductive layer 341 and a second metal electrode 342, with the second transparent conductive layer 341 disposed between the second emitting layer 33 and the second metal electrode 342. The second transparent conductive layer has good optical transmittance and conductivity, which can improve the light utilization rate of the solar cell and enhance its photoelectric conversion efficiency. In one embodiment of this application, the material of the second metal electrode may include, but is not limited to, at least one of gold, silver, and copper. In one embodiment of this application, the material of the second metal electrode may be silver. In one embodiment of this application, the second transparent conductive layer may include, but is not limited to, at least one of ITO (indium tin oxide), AZO (zinc aluminum oxide), and IZO (indium zinc oxide). In one embodiment of this application, the second transparent conductive layer may be ITO (indium tin oxide).

[0092] Please see Figure 6 This is a cross-sectional schematic diagram of a solar cell provided in another embodiment of this application, wherein the second film layer 30 further includes a buffer layer 36 disposed between the second emitter layer 33 and the second electrode layer 34. The buffer layer can improve the interfacial contact between the second emitter layer and the second electrode layer, thereby improving the carrier transport efficiency. In one embodiment of this application, the material of the buffer layer includes at least one of amorphous silicon containing a second doping element and amorphous silicon oxide containing a second doping element. In another embodiment of this application, the material of the buffer layer can be amorphous silicon oxide containing a doping element. The interfacial contact between amorphous silicon oxide and the second electrode layer is better than that between amorphous silicon and the second electrode layer, thereby further improving the electrical performance of the solar cell. In one embodiment of this application, the thickness of the buffer layer is 1nm-2nm. Specifically, the thickness of the buffer layer can be, but is not limited to, 1nm, 1.2nm, 1.4nm, 1.6nm, 1.8nm, or 2nm. In one embodiment of this application, the thickness of the buffer layer can be 1nm-1.6nm. In another embodiment of this application, the thickness of the buffer layer can be 1.4nm-2nm.

[0093] In one embodiment of this application, the molar ratio of the second dopant element to silicon in the buffer layer is 1:(10-30). Specifically, the molar ratio of the second dopant element to silicon in the buffer layer can be, but is not limited to, 1:10, 1:15, 1:18, 1:20, 1:25, 1:27, or 1:30. In one embodiment of this application, the molar ratio of the second dopant element to silicon in the buffer layer can be 1:(10-20). In another embodiment of this application, the molar ratio of the second dopant element to silicon in the buffer layer can be 1:(15-30).

[0094] In one embodiment of this application, the molar ratio of the second dopant element to silicon element in the buffer layer is greater than the molar ratio of the second dopant element to silicon element in the second emitter layer, forming a concentration gradient of the second dopant element, which is beneficial to increasing the number of carriers collected in each film layer.

[0095] Please see Figure 7 This is a cross-sectional schematic diagram of a solar cell provided in another embodiment of this application, wherein the second film layer 30 further includes a second transition layer 35 and a buffer layer 36, with the buffer layer 36 disposed between the second transition layer 35 and the second electrode layer 34. The second transition layer can improve the hole carrier collection capability and enhance the carrier transport efficiency, while the buffer layer can improve the interfacial contact between the second transition layer and the second electrode layer, enhance the photoelectric conversion efficiency, and prevent the second electrode layer from damaging the second transition layer. The simultaneous presence of the second transition layer and the buffer layer can further enhance the photoelectric conversion efficiency of the solar cell and improve the structural stability of the solar cell.

[0096] In one embodiment of this application, the molar ratio of the second dopant element to silicon element in the second emitter layer, the second transition layer and the buffer layer gradually increases, so that a carrier concentration gradient is formed between the three layers, and the carriers are more easily absorbed by the outer second electrode layer, thereby increasing the short-circuit current and further improving the photoelectric conversion efficiency.

[0097] In one embodiment of this application, the photoelectric conversion efficiency of the solar cell is greater than 25%. Specifically, the photoelectric conversion efficiency of the solar cell may be, but is not limited to, greater than 25%, greater than or equal to 25.2%, greater than or equal to 25.3%, greater than or equal to 25.4%, greater than or equal to 25.5%, greater than or equal to 25.8%, or greater than or equal to 26%, etc. In one embodiment of this application, the photoelectric conversion efficiency of the solar cell is greater than or equal to 25.2%.

[0098] This application also provides a method for fabricating a solar cell, comprising: depositing a first film layer and a second film layer on a silicon substrate to obtain a solar cell; the method includes a silicon substrate, a first film layer disposed on the surface of the silicon substrate, and a second film layer disposed on a side surface of the silicon substrate opposite to the first film layer; along the direction from the silicon substrate to the first film layer, the first film layer includes a first emitter layer and a first electrode layer stacked sequentially, the first emitter layer being connected to the surface of the silicon substrate, and the crystallinity of the first emitter layer near the first electrode layer being greater than the crystallinity of the first emitter layer near the silicon substrate; and / or along the direction from the silicon substrate to the second film layer, the second film layer includes a second emitter layer and a second electrode layer stacked sequentially, the second emitter layer being connected to the surface of the silicon substrate, and the crystallinity of the second emitter layer near the second electrode layer being greater than the crystallinity of the second emitter layer near the silicon substrate; the silicon substrate and the first emitter layer have a first dopant element, the second emitter layer has a second dopant element, and the first dopant element and the second dopant element are different.

[0099] Please see Figure 8 The flowchart illustrates a method for fabricating a solar cell according to an embodiment of this application, including:

[0100] S101: A first emitter layer and a first electrode layer are sequentially deposited on the surface of a silicon substrate to obtain a first film layer. The first emitter layer is connected to the surface of the silicon substrate. The crystallinity of the first emitter layer on the side closer to the first electrode layer is greater than that on the side closer to the silicon substrate.

[0101] S102: A second emitter layer and a second electrode layer are sequentially deposited on the surface of a silicon substrate away from the first emitter layer to obtain a second film layer. The second emitter layer is connected to the surface of the silicon substrate. The crystallinity of the second emitter layer near the second electrode layer is greater than that of the side of the second emitter layer near the silicon substrate, thus obtaining a solar cell. The solar cell fabricated by the method provided in this application has good structural stability and high photoelectric conversion efficiency, which is beneficial for the widespread application of solar cells.

[0102] In this application, deposition includes chemical vapor deposition and physical vapor deposition. Specifically, deposition may include, but is not limited to, at least one of atomic layer deposition, plasma-enhanced chemical vapor deposition, sputtering deposition, electron beam deposition, and thermal evaporation deposition. In one embodiment of this application, the deposition is plasma-enhanced chemical deposition. Specifically, depending on the power source used to generate the plasma, the power source for plasma-enhanced chemical deposition may include, but is not limited to, at least one of very high frequency (VHF) and radio frequency (RF). In one embodiment of this application, the power source for plasma-enhanced chemical deposition can be very high frequency (VHF), which can improve the crystallinity of the film and reduce film defects. In one embodiment of this application, the power source for plasma-enhanced chemical deposition of the first passivation layer and the second passivation layer can be radio frequency (RF).

[0103] Please see Figure 9 The flowchart of a method for preparing a solar cell according to another embodiment of this application includes:

[0104] S201: A first seed layer, a first emitter layer, and a first electrode layer are sequentially deposited on the surface of a silicon substrate to obtain a first film layer. The first seed layer is connected to the surface of the silicon substrate, and the crystallinity of the first emitter layer is greater than that of the first seed layer.

[0105] S202: A second seed layer, a second emitter layer, and a second electrode layer are sequentially deposited on the surface of the first seed layer away from the silicon substrate to obtain a second film layer. The second seed layer is connected to the surface of the silicon substrate. The crystallinity of the second emitter layer is greater than that of the second seed layer, thus obtaining a solar cell.

[0106] In one embodiment of this application, the deposition temperature of the first seed layer is 200℃-210℃. Specifically, the deposition temperature of the first seed layer can be, but is not limited to, 200℃, 202℃, 204℃, 206℃, 208℃, or 210℃. In one embodiment of this application, the deposition temperature of the first seed layer can be 200℃-204℃. In another embodiment of this application, the deposition temperature of the first seed layer can be 202℃-210℃. In one embodiment of this application, the deposition pressure of the first seed layer is 2mbar-4mbar. Specifically, the deposition pressure of the first seed layer can be, but is not limited to, 2mbar, 2.2mbar, 2.5mbar, 2.8mbar, 3mbar, 3.5mbar, or 4mbar. In one embodiment of this application, the deposition pressure of the first seed layer can be 2mbar-3.5mbar. In another embodiment of this application, the deposition pressure of the first seed layer can be 3mbar-4mbar. In one embodiment of this application, the deposition power of the first seed layer is 660W / m. 2 -1330W / m 2 Specifically, the deposition power of the first seed layer can be, but is not limited to, 660 W / m. 2 700W / m 2 800W / m 2 900W / m 2 1000W / m 2 1100W / m 2 1200W / m 2 Or 1330W / m 2 Etc. In one embodiment of this application, the deposition power of the first seed layer can be 660 W / m. 2 -900W / m 2 In another embodiment of this application, the deposition power of the first seed layer can be 800 W / m. 2 -1330W / m 2In one embodiment of this application, the hydrogen flow rate during the deposition of the first seed layer is 10000 sccm-12000 sccm. Specifically, the hydrogen flow rate can be, but is not limited to, 10000 sccm, 10500 sccm, 11000 sccm, 11500 sccm, or 12000 sccm. In another embodiment of this application, the hydrogen flow rate during the deposition of the first seed layer can be 10000 sccm-11500 sccm. In yet another embodiment of this application, the hydrogen flow rate during the deposition of the first seed layer can be 11500 sccm-12000 sccm. In one embodiment of this application, the silane flow rate during the deposition of the first seed layer is 20 sccm-40 sccm. Specifically, the silane flow rate can be, but is not limited to, 20 sccm, 25 sccm, 30 sccm, 35 sccm, or 40 sccm. In yet another embodiment of this application, the silane flow rate during the deposition of the first seed layer can be 20 sccm-35 sccm. In another embodiment of this application, the silane flow rate can be 25 sccm-40 sccm during the deposition of the first seed layer. In one embodiment of this application, the flow rate of the phosphine-hydrogen mixture is 50 sccm-100 sccm during the deposition of the first seed layer. In the phosphine-hydrogen mixture, the phosphine gas flow rate is 1 sccm-2 ccm, and the hydrogen gas flow rate is 48 sccm-99 ccm. Specifically, the flow rate of the phosphine-hydrogen mixture can be, but is not limited to, 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm, or 100 sccm. In one embodiment of this application, the phosphine-hydrogen mixture flow rate can be 50 sccm-80 sccm during the deposition of the first seed layer. In another embodiment of this application, the phosphine-hydrogen mixture flow rate can be 65 sccm-100 sccm during the deposition of the first seed layer. In one embodiment of this application, the doping ratio of phosphine and silane during the deposition of the first seed layer is 2%-10%. Specifically, the flow rate doping ratio of phosphine and silane can be, but is not limited to, 2%, 3%, 5%, 7%, 9%, or 10%. In one embodiment of this application, the flow rate doping ratio of phosphine and silane during the deposition of the first seed layer can be 2%-5%. In another embodiment of this application, the flow rate doping ratio of phosphine and silane during the deposition of the first seed layer can be 4%-10%.

[0107] In one embodiment of this application, the deposition temperature of the first emitter layer is 200℃-210℃. Specifically, the deposition temperature of the first emitter layer can be, but is not limited to, 200℃, 202℃, 204℃, 206℃, 208℃, or 210℃. In one embodiment of this application, the deposition temperature of the first emitter layer can be 200℃-204℃. In another embodiment of this application, the deposition temperature of the first emitter layer can be 202℃-210℃. In one embodiment of this application, the deposition pressure of the first emitter layer is 2mbar-4mbar. Specifically, the deposition pressure of the first emitter layer can be, but is not limited to, 2mbar, 2.2mbar, 2.5mbar, 2.8mbar, 3mbar, 3.5mbar, or 4mbar. In one embodiment of this application, the deposition pressure of the first emitter layer can be 2mbar-3.5mbar. In another embodiment of this application, the deposition pressure of the first emitter layer can be 3mbar-4mbar. In one embodiment of this application, the deposition power of the first emission layer is 1330 W / m 2 -2000W / m 2 Specifically, the deposition power of the first emission layer can be, but is not limited to, 1330 W / m. 2 1400W / m 2 1500W / m 2 1600W / m 2 1700W / m 2 1800W / m 2 1900W / m 2 Or 2000W / m 2 Etc. In one embodiment of this application, the deposition power of the first emission layer can be 1330 W / m. 2 -1600W / m 2 In another embodiment of this application, the deposition power of the first emission layer can be 1500 W / m. 2 -2000W / m 2In one embodiment of this application, the hydrogen flow rate during the first emission layer deposition is 10000 sccm-12000 sccm. Specifically, the hydrogen flow rate can be, but is not limited to, 10000 sccm, 10500 sccm, 11000 sccm, 11500 sccm, or 12000 sccm. In another embodiment of this application, the hydrogen flow rate during the first emission layer deposition can be 10000 sccm-11500 sccm. In yet another embodiment of this application, the hydrogen flow rate during the first emission layer deposition can be 11500 sccm-12000 sccm. In one embodiment of this application, the silane flow rate during the first emission layer deposition is 50 sccm-100 sccm. Specifically, the silane flow rate can be, but is not limited to, 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm, or 100 sccm. In one embodiment of this application, the silane flow rate can be 50 sccm-85 sccm during the first emission layer deposition. In another embodiment of this application, the silane flow rate can be 65 sccm-100 sccm during the first emission layer deposition. In one embodiment of this application, the flow rate of the phosphine-hydrogen mixture is 50 sccm-100 sccm during the first emission layer deposition. In the phosphine-hydrogen mixture, the phosphine gas flow rate is 1 sccm-2 ccm, and the hydrogen gas flow rate is 48 sccm-99 ccm. Specifically, the flow rate of the phosphine-hydrogen mixture can be, but is not limited to, 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm, or 100 sccm. In one embodiment of this application, the phosphine-hydrogen mixture flow rate can be 50 sccm-80 sccm during the first emission layer deposition. In another embodiment of this application, the phosphine-hydrogen mixture flow rate can be 65 sccm-100 sccm during the first emission layer deposition. In one embodiment of this application, during the deposition of the first emission layer, the flow rate doping ratio of phosphine and silane is 2%-10%. Specifically, the flow rate doping ratio of phosphine and silane can be, but is not limited to, 2%, 3%, 5%, 7%, 9%, or 10%. In one embodiment of this application, during the deposition of the first emission layer, the flow rate doping ratio of phosphine and silane can be 2%-5%. In another embodiment of this application, during the deposition of the first emission layer, the flow rate doping ratio of phosphine and silane can be 4%-10%.

[0108] In one embodiment of this application, the deposition temperature of the second seed layer is 160℃-180℃. Specifically, the deposition temperature of the second seed layer can be, but is not limited to, 160℃, 165℃, 170℃, 175℃, or 180℃. In one embodiment of this application, the deposition temperature of the second seed layer can be 160℃-175℃. In another embodiment of this application, the deposition temperature of the second seed layer can be 170℃-180℃. In one embodiment of this application, the deposition pressure of the second seed layer is 2mbar-2.5mbar. Specifically, the deposition pressure of the second seed layer can be, but is not limited to, 2mbar, 2.1mbar, 2.2mbar, 2.3mbar, 2.4mbar, or 2.5mbar. In one embodiment of this application, the deposition pressure of the second seed layer can be 2mbar-2.3mbar. In another embodiment of this application, the deposition pressure of the second seed layer can be 2.2mbar-2.5mbar. In one embodiment of this application, the deposition power of the second seed layer is 996W / m. 2 -1662W / m 2 Specifically, the deposition power of the second seed layer can be, but is not limited to, 996 W / m. 2 1000W / m 2 1100W / m 2 1200W / m 2 1300W / m 2 1400W / m 2 1500W / m 2 Or 1662W / m 2 Etc. In one embodiment of this application, the deposition power of the second seed layer can be 996 W / m. 2 -1262W / m 2 In another embodiment of this application, the deposition power of the second seed layer can be 1100 W / m. 2 -1662W / m 2In one embodiment of this application, the hydrogen flow rate during the deposition of the second seed layer is 15000 sccm-25000 sccm. Specifically, the hydrogen flow rate can be, but is not limited to, 15000 sccm, 18000 sccm, 19000 sccm, 20000 sccm, or 25000 sccm. In one embodiment of this application, the hydrogen flow rate during the deposition of the second seed layer can be 15000 sccm-20500 sccm. In another embodiment of this application, the hydrogen flow rate during the deposition of the second seed layer can be 20000 sccm-25000 sccm. In one embodiment of this application, the silane flow rate during the deposition of the second seed layer is 25 sccm-45 sccm. Specifically, the silane flow rate can be, but is not limited to, 25 sccm, 30 sccm, 35 sccm, 40 sccm, or 45 sccm. In one embodiment of this application, the silane flow rate during the deposition of the second seed layer can be 25 sccm-35 sccm. In another embodiment of this application, the silane flow rate can be 30 sccm-45 sccm during the deposition of the second seed layer. In one embodiment of this application, the flow rate of the diborane-hydrogen mixture is 100 sccm-200 sccm during the deposition of the second seed layer. In the diborane-hydrogen mixture, the flow rate of diborane gas is 2 sccm-4 ccm, and the flow rate of hydrogen gas is 96 sccm-198 ccm. Specifically, the flow rate of the diborane-hydrogen mixture can be, but is not limited to, 100 sccm, 130 sccm, 160 sccm, 170 sccm, 180 sccm, 190 sccm, or 200 sccm. In one embodiment of this application, the flow rate of the diborane-hydrogen mixture can be 100 sccm-180 sccm during the deposition of the second seed layer. In another embodiment of this application, the flow rate of the diborane-hydrogen mixture can be 165 sccm-200 sccm during the deposition of the second seed layer.

[0109] In one embodiment of this application, the deposition temperature of the second emitter layer is 160℃-180℃. Specifically, the deposition temperature of the second emitter layer can be, but is not limited to, 160℃, 165℃, 170℃, 175℃, or 180℃. In one embodiment of this application, the deposition temperature of the second emitter layer can be 160℃-170℃. In another embodiment of this application, the deposition temperature of the second emitter layer can be 165℃-180℃. In one embodiment of this application, the deposition pressure of the second emitter layer is 1.5mbar-2.2mbar. Specifically, the deposition pressure of the second emitter layer can be, but is not limited to, 1.5mbar, 1.6mbar, 1.8mbar, 1.9mbar, 2mbar, 2.1mbar, or 2.2mbar. In one embodiment of this application, the deposition pressure of the second emitter layer can be 1.5mbar-1.9mbar. In another embodiment of this application, the deposition pressure of the second emitter layer can be 1.8mbar-2.2mbar. In one embodiment of this application, the deposition power of the second emission layer is 1662 W / m. 2 -2660W / m 2 Specifically, the deposition power of the second emission layer can be, but is not limited to, 1662 W / m². 2 1700W / m 2 1800W / m 2 1900W / m 2 2000W / m 2 2200W / m 2 2400W / m 2 Or 2660W / m 2 Etc. In one embodiment of this application, the deposition power of the second emission layer can be 1662 W / m. 2 -2160W / m 2 In another embodiment of this application, the deposition power of the second emission layer can be 2200 W / m. 2 -2660W / m 2In one embodiment of this application, the hydrogen flow rate during the deposition of the second emission layer is 30,000 sccm-50,000 sccm. Specifically, the hydrogen flow rate can be, but is not limited to, 30,000 sccm, 35,000 sccm, 40,000 sccm, 45,000 sccm, or 50,000 sccm. In another embodiment of this application, the hydrogen flow rate during the deposition of the second emission layer can be 30,000 sccm-45,500 sccm. In yet another embodiment of this application, the hydrogen flow rate during the deposition of the second emission layer can be 35,000 sccm-50,000 sccm. In one embodiment of this application, the silane flow rate during the deposition of the second emission layer is 30 sccm-160 sccm. Specifically, the silane flow rate can be, but is not limited to, 30 sccm, 80 sccm, 90 sccm, 80 sccm, 90 sccm, or 100 sccm. In one embodiment of this application, the silane flow rate can be 50 sccm-85 sccm during the deposition of the second emission layer. In another embodiment of this application, the silane flow rate can be 65 sccm-100 sccm during the deposition of the second emission layer. In one embodiment of this application, the flow rate of the diborane-hydrogen mixture is 20 sccm-30 sccm during the deposition of the second emission layer. In the diborane-hydrogen mixture, the flow rate of diborane gas is 0.4 sccm-0.6 ccm, and the flow rate of hydrogen gas is 19.4 sccm-29.6 ccm. Specifically, the flow rate of the diborane-hydrogen mixture can be, but is not limited to, 20 sccm, 22 sccm, 24 sccm, 26 sccm, 28 sccm, or 30 sccm. In one embodiment of this application, the flow rate of the diborane-hydrogen mixture can be 20 sccm-26 sccm during the deposition of the second emission layer. In another embodiment of this application, the flow rate of the diborane-hydrogen mixture during the deposition of the second emission layer can be 24 sccm-30 sccm. In one embodiment of this application, the flow rate doping ratio of diborane and silane during the deposition of the second emission layer is 0.3%-1%. Specifically, the flow rate doping ratio of diborane and silane can be, but is not limited to, 0.3%, 0.5%, 0.7%, 0.9%, or 1%. In one embodiment of this application, the flow rate doping ratio of diborane and silane during the deposition of the second emission layer can be 0.3%-0.6%. In another embodiment of this application, the flow rate doping ratio of diborane and silane during the deposition of the second emission layer can be 0.5%-1%.

[0110] Please see Figure 10 Here is a flowchart of a method for preparing a solar cell according to one embodiment of this application, including:

[0111] S301: A first passivation layer, a first seed layer, a first emitter layer, and a first electrode layer are sequentially deposited on the surface of a silicon substrate to obtain a first film layer. The first passivation layer is connected to the surface of the silicon substrate, and the crystallinity of the first emitter layer is greater than that of the first seed layer.

[0112] S302: A second passivation layer, a second seed layer, a second emitter layer, and a second electrode layer are sequentially deposited on the surface of the first passivation layer away from the silicon substrate to obtain a second film layer. The second passivation layer is connected to the surface of the silicon substrate. The crystallinity of the second emitter layer is greater than that of the second seed layer, thus obtaining a solar cell.

[0113] In one embodiment of this application, the deposition temperature of the first passivation layer is 160℃-190℃. Specifically, the deposition temperature of the first passivation layer can be, but is not limited to, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, or 190℃. In one embodiment of this application, the deposition temperature of the first passivation layer can be 160℃-180℃. In another embodiment of this application, the deposition temperature of the first passivation layer can be 170℃-190℃. In one embodiment of this application, the deposition pressure of the first passivation layer is 0.5mbar-1.5mbar. Specifically, the deposition pressure of the first passivation layer can be, but is not limited to, 0.5mbar, 0.8mbar, 0.9mbar, 1mbar, 1.2mbar, 1.4mbar, or 1.5mbar. In one embodiment of this application, the deposition pressure of the first passivation layer can be 0.5mbar-1mbar. In another embodiment of this application, the deposition pressure of the first passivation layer can be 0.8mbar-1.5mbar. In one embodiment of this application, the deposition power of the first passivation layer is 166 W / m. 2 -664W / m 2 Specifically, the deposition power of the first passivation layer can be, but is not limited to, 166 W / m. 2 200W / m 2 300W / m 2 400W / m 2 500W / m 2 600W / m 2 Or 664W / m 2 Etc. In one embodiment of this application, the deposition power of the first passivation layer can be 166 W / m. 2 -400W / m 2 In another embodiment of this application, the deposition power of the first passivation layer can be 350 W / m. 2 -664W / m 2In one embodiment of this application, the silane flow rate during the deposition of the first passivation layer is 150 sccm-500 sccm. Specifically, the silane flow rate of the first passivation layer can be, but is not limited to, 150 sccm, 200 sccm, 250 sccm, 300 sccm, 400 sccm, or 500 sccm. In another embodiment of this application, the silane flow rate of the first passivation layer can be 150 sccm-400 sccm. In yet another embodiment of this application, the silane flow rate of the first passivation layer can be 300 sccm-500 sccm. In one embodiment of this application, the hydrogen flow rate during the deposition of the first passivation layer is 1500 sccm-2500 sccm. Specifically, the hydrogen flow rate of the first passivation layer can be, but is not limited to, 1500 sccm, 1700 sccm, 1800 sccm, 1900 sccm, 2000 sccm, 2200 sccm, or 2500 sccm. In one embodiment of this application, the hydrogen flow rate of the first passivation layer can be 1500 sccm-2000 sccm. In another embodiment of this application, the hydrogen flow rate of the first passivation layer can be 1900 sccm-2500 sccm.

[0114] In one embodiment of this application, a carbon dioxide plasma treatment is performed after the first passivation layer is formed. Carbon dioxide plasma treatment can form an ultrathin amorphous silicon oxide layer on the surface of the first passivation layer, utilizing its tunneling effect to enhance carrier transport capability. In one embodiment of this application, the temperature of the carbon dioxide plasma treatment is 200℃-210℃. Specifically, the temperature of the carbon dioxide plasma treatment can be, but is not limited to, 200℃, 202℃, 204℃, 206℃, 208℃, or 210℃. In one embodiment of this application, the temperature of the carbon dioxide plasma treatment can be 200℃-204℃. In another embodiment of this application, the temperature of the carbon dioxide plasma treatment can be 202℃-210℃. In one embodiment of this application, the pressure of the carbon dioxide plasma treatment is 0.5mbar-2mbar. Specifically, the pressure of the carbon dioxide plasma treatment can be, but is not limited to, 0.5mbar, 0.8mbar, 1.2mbar, 1.5mbar, 1.8mbar, or 2mbar. In one embodiment of this application, the pressure of the carbon dioxide plasma treatment can be 0.5mbar-1.2mbar. In another embodiment of this application, the pressure of the carbon dioxide plasma treatment can be 1.1 mbar-2 mbar. In one embodiment of this application, the power of the carbon dioxide plasma treatment is 66.4 W / m. 2 -200W / m 2 Specifically, the power for carbon dioxide plasma treatment can be, but is not limited to, 66.4 W / m². 2 100W / m 2 120W / m2 140W / m 2 160W / m 2 180W / m 2 Or 200W / m 2 Etc. In one embodiment of this application, the power of the carbon dioxide plasma treatment can be 66.4 W / m. 2 -130W / m 2 In another embodiment of this application, the power of the carbon dioxide plasma treatment can be 120 W / m³. 2 -200W / m 2 In one embodiment of this application, the carbon dioxide plasma treatment time is 5s-15s. Specifically, the carbon dioxide plasma treatment time can be, but is not limited to, 5s, 6s, 7s, 8s, 10s, 12s, 14s, or 15s. In another embodiment of this application, the carbon dioxide plasma treatment time can be 5s-12s. In yet another embodiment of this application, the carbon dioxide plasma treatment time can be 10s-15s. In one embodiment of this application, the carbon dioxide flow rate in the carbon dioxide plasma treatment is 50sccm-200sccm. Specifically, the carbon dioxide flow rate in the carbon dioxide plasma treatment can be, but is not limited to, 50sccm, 80sccm, 90sccm, 120sccm, 150sccm, 180sccm, or 200sccm. In one embodiment of this application, the carbon dioxide flow rate in the carbon dioxide plasma treatment can be 50sccm-120sccm. In yet another embodiment of this application, the carbon dioxide flow rate in the carbon dioxide plasma treatment can be 100sccm-200sccm.

[0115] In one embodiment of this application, the deposition temperature of the second passivation layer is 160℃-190℃. Specifically, the deposition temperature of the second passivation layer can be, but is not limited to, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, or 190℃. In one embodiment of this application, the deposition temperature of the second passivation layer can be 160℃-180℃. In another embodiment of this application, the deposition temperature of the second passivation layer can be 170℃-190℃. In one embodiment of this application, the deposition power of the second passivation layer is 166W / m. 2 -664W / m 2 Specifically, the deposition power of the second passivation layer can be, but is not limited to, 166 W / m. 2 200W / m 2 300W / m 2 400W / m 2 500W / m 2 600W / m 2 Or 664W / m 2In one embodiment of this application, the deposition power of the second passivation layer can be 166 W / m. 2 -400W / m 2 In another embodiment of this application, the deposition power of the second passivation layer can be 350 W / m. 2 -664W / m 2 In one embodiment of this application, the deposition pressure of the second passivation layer is 0.5 mbar-1.5 mbar. Specifically, the deposition pressure of the second passivation layer can be, but is not limited to, 0.5 mbar, 0.8 mbar, 0.9 mbar, 1 mbar, 1.2 mbar, 1.4 mbar, or 1.5 mbar. In another embodiment of this application, the deposition pressure of the second passivation layer can be 0.5 mbar-1 mbar. In yet another embodiment of this application, the deposition pressure of the second passivation layer can be 0.8 mbar-1.5 mbar. In one embodiment of this application, the silane flow rate during the deposition of the second passivation layer is 150 sccm-500 sccm. Specifically, the silane flow rate of the second passivation layer can be, but is not limited to, 150 sccm, 200 sccm, 250 sccm, 300 sccm, 400 sccm, or 500 sccm. In yet another embodiment of this application, the silane flow rate of the second passivation layer can be 150 sccm-400 sccm. In another embodiment of this application, the silane flow rate of the second passivation layer can be 300 sccm-500 sccm. In one embodiment of this application, the hydrogen flow rate during the deposition of the second passivation layer is 1500 sccm-2500 sccm. Specifically, the hydrogen flow rate of the second passivation layer can be, but is not limited to, 1500 sccm, 1700 sccm, 1800 sccm, 1900 sccm, 2000 sccm, 2200, or 2500 sccm. In one embodiment of this application, the hydrogen flow rate of the second passivation layer can be 1500 sccm-2000 sccm. In another embodiment of this application, the hydrogen flow rate of the second passivation layer can be 1900 sccm-2500 sccm.

[0116] In one embodiment of this application, carbon dioxide plasma treatment is performed after the second passivation layer is formed. Carbon dioxide plasma treatment can form an ultrathin amorphous silicon oxide layer on the surface of the second passivation layer, utilizing its tunneling effect to improve carrier transport capability. In one embodiment of this application, the temperature of the carbon dioxide plasma treatment is 200℃-210℃. Specifically, the temperature of the carbon dioxide plasma treatment can be, but is not limited to, 200℃, 202℃, 204℃, 206℃, 208℃, or 210℃. In one embodiment of this application, the temperature of the carbon dioxide plasma treatment can be 200℃-204℃. In another embodiment of this application, the temperature of the carbon dioxide plasma treatment can be 202℃-210℃. In one embodiment of this application, the power of the carbon dioxide plasma treatment is 66.4 W / m. 2 -200W / m 2 Specifically, the power for carbon dioxide plasma treatment can be, but is not limited to, 66.4 W / m². 2 100W / m 2 120W / m 2 140W / m 2 160W / m 2 180W / m 2 Or 200W / m 2 In one embodiment of this application, the power of the carbon dioxide plasma treatment can be 66.4 W / m². 2 -150W / m 2 In another embodiment of this application, the power of the carbon dioxide plasma treatment can be 120 W / m³. 2 -200W / m 2In one embodiment of this application, the pressure of the carbon dioxide plasma treatment is 0.5 mbar-2 mbar. Specifically, the pressure of the carbon dioxide plasma treatment can be, but is not limited to, 0.5 mbar, 0.8 mbar, 1.2 mbar, 1.5 mbar, 1.8 mbar, or 2 mbar. In one embodiment of this application, the pressure of the carbon dioxide plasma treatment can be 0.5 mbar-1.2 mbar. In another embodiment of this application, the pressure of the carbon dioxide plasma treatment can be 1.1 mbar-2 mbar. In one embodiment of this application, the time of the carbon dioxide plasma treatment is 5 s-15 s. Specifically, the time of the carbon dioxide plasma treatment can be, but is not limited to, 5 s, 6 s, 7 s, 8 s, 10 s, 12 s, 14 s, or 15 s. In one embodiment of this application, the time of the carbon dioxide plasma treatment can be 5 s-12 s. In another embodiment of this application, the time of the carbon dioxide plasma treatment can be 10 s-15 s. In one embodiment of this application, the carbon dioxide flow rate in the carbon dioxide plasma treatment is 50 sccm-200 sccm. Specifically, the carbon dioxide flow rate for carbon dioxide plasma treatment can be, but is not limited to, 50 sccm, 80 sccm, 90 sccm, 120 sccm, 150 sccm, 180 sccm, or 200 sccm. In one embodiment of this application, the carbon dioxide flow rate for carbon dioxide plasma treatment can be 50 sccm-120 sccm. In another embodiment of this application, the carbon dioxide flow rate for carbon dioxide plasma treatment can be 100 sccm-200 sccm.

[0117] Please see Figure 11 The flowchart of a method for preparing a solar cell according to another embodiment of this application includes:

[0118] S401: A first passivation layer, a first seed layer, a first emitter layer, a first transition layer, and a first electrode layer are sequentially deposited on the surface of a silicon substrate to obtain a first film layer. The first passivation layer is connected to the surface of the silicon substrate, and the crystallinity of the first emitter layer is greater than that of the first seed layer.

[0119] S402: A second passivation layer, a second seed layer, a second emitter layer, a second transition layer, and a second electrode layer are sequentially deposited on the surface away from the silicon substrate to obtain a second film layer. The second passivation layer is connected to the surface of the silicon substrate. The crystallinity of the second emitter layer is greater than that of the second seed layer, thus obtaining a solar cell.

[0120] In one embodiment of this application, the deposition temperature of the first transition layer is 190℃-210℃. Specifically, the deposition temperature of the first transition layer can be, but is not limited to, 190℃, 195℃, 200℃, 206℃, 208℃, or 210℃. In one embodiment of this application, the deposition temperature of the first transition layer can be 190℃-204℃. In another embodiment of this application, the deposition temperature of the first transition layer can be 202℃-210℃. In one embodiment of this application, the deposition pressure of the first transition layer is 0.5mbar-1mbar. Specifically, the deposition pressure of the first transition layer can be, but is not limited to, 0.5mbar, 0.55mbar, 0.6mbar, 0.8mbar, 0.9mbar, or 1mbar. In one embodiment of this application, the deposition pressure of the first transition layer can be 0.5mbar-0.85mbar. In another embodiment of this application, the deposition pressure of the first transition layer can be 0.6mbar-1mbar. In one embodiment of this application, the deposition power of the first transition layer is 265W / m. 2 -664W / m 2 Specifically, the deposition power of the first transition layer can be, but is not limited to, 265 W / m. 2 300W / m 2 350W / m 2 400W / m 2 450W / m 2 500W / m 2 550W / m 2 600W / m 2 Or 664W / m 2 In one embodiment of this application, the deposition power of the first transition layer can be 265 W / m. 2 -400W / m 2 In another embodiment of this application, the deposition power of the first transition layer can be 350 W / m. 2 -664W / m 2In one embodiment of this application, the hydrogen flow rate is 300 sccm-500 sccm during the deposition of the first transition layer. Specifically, the hydrogen flow rate can be, but is not limited to, 300 sccm, 350 sccm, 400 sccm, 450 sccm, or 500 sccm. In another embodiment of this application, the hydrogen flow rate can be 300 sccm-450 sccm during the deposition of the first transition layer. In yet another embodiment of this application, the hydrogen flow rate can be 400 sccm-500 sccm during the deposition of the first transition layer. In one embodiment of this application, the silane flow rate is 100 sccm-200 sccm during the deposition of the first transition layer. Specifically, the silane flow rate can be, but is not limited to, 100 sccm, 120 sccm, 140 sccm, 150 sccm, 170 sccm, or 200 sccm. In yet another embodiment of this application, the silane flow rate can be 100 sccm-180 sccm during the deposition of the first transition layer. In another embodiment of this application, the silane flow rate can be 160 sccm-200 sccm during the deposition of the first transition layer. In one embodiment of this application, the flow rate of the phosphine-hydrogen mixture is 300 sccm-500 sccm during the deposition of the first transition layer. In the phosphine-hydrogen mixture, the phosphine gas flow rate is 6 sccm-10 ccm, and the hydrogen gas flow rate is 290 sccm-494 ccm. Specifically, the flow rate of the phosphine-hydrogen mixture can be, but is not limited to, 300 sccm, 320 sccm, 380 sccm, 400 sccm, 4500 sccm, or 500 sccm. In one embodiment of this application, the flow rate of the phosphine-hydrogen mixture can be 300 sccm-450 sccm during the deposition of the first transition layer. In another embodiment of this application, the flow rate of the phosphine-hydrogen mixture can be 380 sccm-500 sccm during the deposition of the first transition layer.

[0121] In one embodiment of this application, the deposition temperature of the second transition layer is 160℃-180℃. Specifically, the deposition temperature of the second transition layer can be, but is not limited to, 160℃, 165℃, 170℃, 175℃, or 180℃. In one embodiment of this application, the deposition temperature of the second transition layer can be 160℃-170℃. In another embodiment of this application, the deposition temperature of the second transition layer can be 165℃-180℃. In one embodiment of this application, the deposition power of the second transition layer is 1661W / m. 2 -2658W / m 2 Specifically, the deposition power of the second transition layer can be, but is not limited to, 1661 W / m. 2 1700W / m 2 1800W / m 2 1900W / m 2 2000W / m 22100W / m 2 2400W / m 2 2600W / m 2 Or 2658W / m 2 In one embodiment of this application, the deposition power of the second transition layer can be 2500W-2980W. In another embodiment of this application, the deposition power of the second transition layer can be 2800W-4000W. In one embodiment of this application, the deposition pressure of the second transition layer is 2mbar-4mbar. Specifically, the deposition pressure of the second transition layer can be, but is not limited to, 2mbar, 2.2mbar, 2.5mbar, 2.8mbar, 3mbar, 3.5mbar, or 4mbar. In one embodiment of this application, the deposition pressure of the second transition layer can be 2mbar-3.5mbar. In another embodiment of this application, the deposition pressure of the second transition layer can be 3mbar-4mbar. In one embodiment of this application, during the deposition of the second transition layer, the hydrogen flow rate is 30000sccm-50000sccm. Specifically, the hydrogen flow rate can be, but is not limited to, 30000sccm, 35000sccm, 40000sccm, 45000sccm, or 50000sccm. In one embodiment of this application, the hydrogen flow rate during the deposition of the second transition layer can be 30,000 sccm-45,500 sccm. In another embodiment of this application, the hydrogen flow rate during the deposition of the second transition layer can be 35,000 sccm-50,000 sccm. In one embodiment of this application, the silane flow rate during the deposition of the second transition layer is 30 sccm-160 sccm. Specifically, the silane flow rate can be, but is not limited to, 30 sccm, 80 sccm, 90 sccm, 80 sccm, 90 sccm, or 100 sccm. In one embodiment of this application, the silane flow rate during the deposition of the second transition layer can be 50 sccm-85 sccm. In another embodiment of this application, the silane flow rate during the deposition of the second transition layer can be 65 sccm-100 sccm. In one embodiment of this application, the flow rate of the diborane-hydrogen mixture during the deposition of the second transition layer is 200 sccm-300 sccm. In the diborane-hydrogen mixture, the flow rate of diborane gas is 4 sccm-6 ccm, and the flow rate of hydrogen gas is 194 sccm-296 ccm. Specifically, the flow rate of the diborane-hydrogen mixture can be, but is not limited to, 200 sccm, 220 sccm, 240 sccm, 260 sccm, 280 sccm, or 300 sccm. In one embodiment of this application, during the deposition of the second transition layer, the flow rate of the diborane-hydrogen mixture can be 200 sccm-260 sccm. In another embodiment of this application, during the deposition of the second transition layer, the flow rate of the diborane-hydrogen mixture can be 240 sccm-300 sccm.

[0122] Please see Figure 12 The flowchart of a method for preparing a solar cell according to another embodiment of this application includes:

[0123] S501: A first passivation layer, a first seed layer, a first emitter layer, a first transition layer, and a first electrode layer are sequentially deposited on the surface of a silicon substrate to obtain a first film layer. The first passivation layer is connected to the surface of the silicon substrate, and the crystallinity of the first emitter layer is greater than that of the first seed layer.

[0124] S502: A second passivation layer, a second seed layer, a second emitter layer, a second transition layer, a buffer layer, and a second electrode layer are sequentially deposited on the surface away from the silicon substrate to obtain a second film layer. The second passivation layer is connected to the surface of the silicon substrate. The crystallinity of the second emitter layer is greater than that of the second seed layer, thus obtaining a solar cell.

[0125] In one embodiment of this application, after forming the second transition layer, a buffer layer is deposited on the surface of the second transition layer to improve the contact between the upper and lower film layers, thereby increasing the short-circuit current and fill factor. During the deposition of the second electrode layer, the buffer layer can protect the second transition layer, preventing damage from the second electrode layer.

[0126] In one embodiment of this application, the deposition temperature of the buffer layer is 160℃-180℃. Specifically, the deposition temperature of the buffer layer can be, but is not limited to, 160℃, 165℃, 170℃, 175℃, or 180℃. In one embodiment of this application, the deposition temperature of the buffer layer can be 160℃-170℃. In another embodiment of this application, the deposition temperature of the buffer layer can be 165℃-180℃. In one embodiment of this application, the deposition pressure of the buffer layer is 0.3mbar-1mbar. Specifically, the deposition pressure of the buffer layer can be, but is not limited to, 0.3mbar, 0.4mbar, 0.5mbar, 0.6mbar, 0.7mbar, 0.8mbar, or 1mbar. In one embodiment of this application, the deposition pressure of the buffer layer can be 0.3mbar-0.8mbar. In another embodiment of this application, the deposition pressure of the buffer layer can be 0.5mbar-1mbar. In one embodiment of this application, the deposition power of the buffer layer is 332W / m. 2 -664W / m 2 Specifically, the deposition power of the buffer layer can be, but is not limited to, 332 W / m. 2 350W / m 2 400W / m 2 450W / m 2 500W / m 2 550W / m 2600W / m 2 Or 664W / m 2 Etc. In one embodiment of this application, the deposition power of the buffer layer can be 332 W / m. 2 -500W / m 2 In another embodiment of this application, the deposition power of the buffer layer can be 450 W / m. 2 -664W / m 2 In one embodiment of this application, the carbon dioxide flow rate during buffer layer deposition is 100 sccm-200 sccm. Specifically, the hydrogen flow rate can be, but is not limited to, 100 sccm, 120 sccm, 150 sccm, 180 sccm, or 200 sccm. In one embodiment of this application, the hydrogen flow rate during buffer layer deposition can be 100 sccm-155 sccm. In another embodiment of this application, the hydrogen flow rate during buffer layer deposition can be 120 sccm-200 sccm. In one embodiment of this application, the hydrogen flow rate during buffer layer deposition is 300 sccm-500 sccm. Specifically, the hydrogen flow rate can be, but is not limited to, 300 sccm, 350 sccm, 400 sccm, 450 sccm, or 500 sccm. In one embodiment of this application, the hydrogen flow rate during buffer layer deposition can be 300 sccm-455 sccm. In another embodiment of this application, the hydrogen flow rate during buffer layer deposition can be 350 sccm-500 sccm. In one embodiment of this application, the silane flow rate is 100 sccm-200 sccm during buffer layer deposition. Specifically, the silane flow rate can be, but is not limited to, 100 sccm, 120 sccm, 140 sccm, 160 sccm, 180 sccm, or 200 sccm. In one embodiment of this application, the silane flow rate can be 100 sccm-165 sccm during buffer layer deposition. In another embodiment of this application, the silane flow rate can be 140 ccm-200 sccm during buffer layer deposition. In one embodiment of this application, the flow rate of the diborane-hydrogen mixture is 400 sccm-600 sccm during buffer layer deposition. In the diborane-hydrogen mixture, the flow rate of diborane gas is 8 sccm-12 ccm, and the flow rate of hydrogen gas is 388 sccm-592 ccm. Specifically, the flow rate of the diborane-hydrogen mixture can be, but is not limited to, 400 sccm, 420 sccm, 450 sccm, 500 sccm, 550 sccm, or 600 sccm. In one embodiment of this application, the flow rate of the diborane-hydrogen mixture during buffer layer deposition can be 400 sccm-560 sccm. In another embodiment of this application, the flow rate of the diborane-hydrogen mixture during buffer layer deposition can be 500 sccm-600 sccm.

[0127] In one embodiment of this application, hydrogen plasma treatment is included before and / or after the formation of the first seed layer, first emitter layer, first transition layer, second passivation layer, second seed layer, second emitter layer, second transition layer, and buffer layer. This can improve the crystallinity and growth defects of each film layer. Simultaneously, the first passivation layer is not subjected to hydrogen plasma treatment, preserving the silicon oxide naturally formed on its surface, which is beneficial for carrier and electron transport and improves carrier transport efficiency. In another embodiment of this application, hydrogen plasma treatment is included after the deposition of the second passivation layer and before carbon dioxide plasma treatment. This utilizes a large amount of hydrogen plasma to compensate for the dangling bonds of surface silicon in the second emitter layer, while simultaneously providing a hydrogen-rich environment for the second transition layer, reducing the possibility of film bursting.

[0128] In one embodiment of this application, the pressure of the hydrogen plasma treatment is 0.5 mbar-1.5 mbar. Specifically, the pressure of the hydrogen plasma treatment can be, but is not limited to, 0.5 mbar, 1 mbar, 1.3 mbar, 1.35 mbar, 1.4 mbar, or 1.5 mbar. In one embodiment of this application, before the formation of the first seed layer, the pressure of the hydrogen plasma treatment can be 1.2 mbar-1.5 mbar. In another embodiment of this application, before the formation of the second seed layer, the pressure of the hydrogen plasma treatment can be 0.5 mbar-1 mbar. In one embodiment of this application, the power of the hydrogen plasma treatment is 119 W / m. 2 -332W / m 2 Specifically, the power for hydrogen plasma treatment can be, but is not limited to, 119 W / m³. 2 150W / m 2 180W / m 2 200W / m 2 220W / m 2 280W / m 2 290W / m 2 300W / m 2 Or 332W / m 2 Etc. In one embodiment of this application, the power of the hydrogen plasma treatment can be 119 W / m³. 2 -220W / m 2 In another embodiment of this application, the power of the hydrogen plasma treatment can be 210 W / m³. 2 -332W / m 2In one embodiment of this application, the hydrogen plasma treatment time is 8s-40s. Specifically, the hydrogen plasma treatment time can be, but is not limited to, 8s, 10s, 18s, 20s, 25s, 30s, or 40s. In one embodiment of this application, the hydrogen plasma treatment time before the formation of the first seed layer can be 8s-15s. In another embodiment of this application, the hydrogen plasma treatment time before the formation of the second seed layer can be 20s-40s. In one embodiment of this application, the hydrogen flow rate for hydrogen plasma treatment is 1500sccm-3000sccm. Specifically, the carbon dioxide flow rate for hydrogen plasma treatment can be, but is not limited to, 1500sccm, 1600sccm, 1850sccm, 2000sccm, 2500sccm, 2900sccm, or 3000sccm. In one embodiment of this application, the hydrogen flow rate for hydrogen plasma treatment before the formation of the first seed layer, the first emission layer, and the first transition layer can be 1500sccm-2000sccm. In another embodiment of this application, before the formation of the second seed layer, the second emission layer, the second transition layer, and / or the buffer layer, the hydrogen flow rate for hydrogen plasma treatment can be 2000 sccm-3000 sccm.

[0129] This application also provides a solar cell, which includes the solar cell wafer provided in any of the above embodiments. The solar cell provided in this application has high photoelectric conversion efficiency and good safety in use, which is beneficial to improving the application of solar cells.

[0130] This application also provides an electrical device, which includes the solar cell provided in any of the above embodiments. The electrical device provided by this application has excellent overall performance, high photoelectric conversion efficiency, and improves the market competitiveness of the electrical device.

[0131] The effects of the technical solution in this application will be further illustrated below with specific examples.

[0132] Example 1

[0133] Plasma-chemical vapor deposition (PCVDC) of the first and second passivation layers was performed on both sides of an N-type silicon substrate using a 13.56 MHz RF power supply. The deposition temperature was 190 °C, the pressure was 1.2 mbar, and the power was 531 W / m. 2 The silane flow rate is 160 sccm, and the hydrogen flow rate is 1600 sccm. The first passivation layer is made of amorphous silicon with a thickness of 7.5 nm, and the second passivation layer is made of amorphous silicon with a thickness of 13 nm.

[0134] The surface of the first passivation layer was treated with hydrogen plasma using a 40MHz VHF power supply. During the hydrogen plasma treatment, the hydrogen flow rate was 1600 sccm, the pressure was 0.7 mbar, and the power was 249 W / m³. 2 The time is 30 seconds.

[0135] The first passivation layer was treated with carbon dioxide plasma using a 40MHz VHF power supply. The carbon dioxide flow rate was 160 sccm, the pressure was 0.7 mbar, and the power was 106 W / m³. 2 The time was 10 seconds and the temperature was 205℃.

[0136] A first seed layer was deposited on the surface of the first passivation layer after carbon dioxide plasma treatment using a 40 MHz VHF power supply. The deposition temperature was 210 °C, the deposition pressure was 3 mbar, and the deposition power was 664 W / m. 2 The hydrogen flow rate is 11000 sccm, the silane flow rate is 25 sccm, and the phosphine-hydrogen mixture flow rate is 50 sccm, with the phosphine / silane flow rate doping ratio controlled at 4%. The first seed layer is made of phosphorus-doped microcrystalline silicon with a crystallinity of approximately 0.3 and a film thickness of 3 nm. The molar ratio of phosphorus to silicon is 1:25.

[0137] The surface of the first seed layer was treated with hydrogen plasma using a 40MHz VHF power supply. During the hydrogen plasma treatment, the hydrogen flow rate was 1600 sccm, the pressure was 0.7 mbar, and the power was 249 W / m³. 2 The time is 30 seconds.

[0138] A first transmitter layer was deposited on the surface of the first seed layer using a 40MHz VHF power supply. The deposition temperature was 200℃, the deposition pressure was 3mbar, and the deposition power was 1661W / m. 2 The hydrogen flow rate was 11000 sccm, the silane flow rate was 66 sccm, and the phosphine-hydrogen mixture flow rate was 180 sccm, with the phosphine / silane doping ratio controlled at 5.4%. The first emission layer was made of phosphorus-doped microcrystalline silicon oxide with a crystallinity of approximately 0.45 and a film thickness of 15 nm. The molar ratio of phosphorus to silicon was 1:18.

[0139] The surface of the first emission layer was treated with hydrogen plasma using a 40MHz VHF power supply. During the hydrogen plasma treatment, the hydrogen flow rate was 1600 sccm, the pressure was 0.7 mbar, and the power was 249 W / m³. 2 The time is 30 seconds.

[0140] A first transition layer was deposited on the surface of the first transmit layer using a 40MHz VHF power supply. The deposition temperature was 200℃, the deposition pressure was 1mbar, and the deposition power was 664W / m. 2 The hydrogen flow rate is 11000 sccm, the silane flow rate is 66 sccm, and the phosphine-hydrogen mixture flow rate is 264 sccm, with the phosphine / silane flow rate doping ratio controlled at 8%. The first transition layer is made of phosphorus-doped microcrystalline silicon with a film thickness of 2 nm and a phosphorus to silicon doping molar ratio of 1:12.5.

[0141] The surface of the second passivation layer was treated with hydrogen plasma using a 40MHz VHF power supply. During the hydrogen plasma treatment, the hydrogen flow rate was 2400 sccm, the pressure was 0.7 mbar, and the power was 249 W / m³. 2 The time is 30 seconds.

[0142] The second passivation layer after hydrogen treatment was subjected to carbon dioxide plasma treatment using a 40MHz VHF power supply. The carbon dioxide flow rate was 720 sccm, the pressure was 0.7 mbar, and the power was 106 W / m³. 2 The time was 10 seconds and the temperature was 200℃.

[0143] A second seed layer was deposited on the surface of the second passivation layer after carbon dioxide plasma treatment using a 40 MHz VHF power supply. The deposition temperature was 170 °C, the deposition pressure was 2.25 mbar, and the deposition power was 2259 W / m. 2 The hydrogen flow rate is 20,000 sccm, the silane flow rate is 40 sccm, and the flow rate of the diborane-hydrogen mixture is 100-200 sccm, controlling the diborane / silane flow rate doping ratio at 7%. The second seed layer is made of boron-doped microcrystalline silicon with a crystallinity of approximately 0.35 and a film thickness of 1-3 nm, with a boron to silicon molar ratio of 1:7.

[0144] The surface of the second seed layer was treated with hydrogen plasma using a 40MHz VHF power supply. During the hydrogen plasma treatment, the hydrogen flow rate was 2400 sccm, the pressure was 0.7 mbar, and the power was 249 W / m³. 2 The time is 30 seconds.

[0145] A second emitter layer was deposited on the surface of the second seed layer using a 40MHz VHF power supply. The deposition temperature was 170℃, the deposition pressure was 3.7mbar, and the deposition power was 2658W / m². 2The hydrogen flow rate is 40200 sccm, the silane flow rate is 120 sccm, and the flow rate of the diborane-hydrogen mixture is 20 sccm, with the diborane / silane doping ratio controlled at 0.33%. The second emission layer is made of boron-doped microcrystalline silicon with a crystallinity of approximately 0.5 and a film thickness of 25 nm. The molar ratio of boron to silicon is 1:150.

[0146] The surface of the second emitter layer was treated with hydrogen plasma using a 40MHz VHF power supply. During the hydrogen plasma treatment, the hydrogen flow rate was 2400 sccm, the pressure was 0.7 mbar, and the power was 249 W / m³. 2 The time is 30 seconds.

[0147] A second transition layer was deposited on the surface of the second transmit layer using a 40MHz VHF power supply. The deposition temperature was 170℃, the deposition pressure was 3.5mbar, and the deposition power was 3987W / m². 2 The hydrogen flow rate is 40-200 sccm, the silane flow rate is 200 sccm, and the flow rate of the diborane-hydrogen mixture is 300 sccm, with the diborane-silane flow rate and doping ratio controlled at 3%. The second transition layer is made of boron-doped microcrystalline silicon with a film thickness of 5-6 nm and a boron to silicon molar ratio of 2:33.

[0148] The surface of the second transition layer was treated with hydrogen plasma using a 40MHz VHF power supply. During the hydrogen plasma treatment, the hydrogen flow rate was 2400 sccm, the pressure was 0.7 mbar, and the power was 249 W / m³. 2 The time is 30 seconds.

[0149] A buffer layer was deposited on the surface of the second transition layer using a 40MHz VHF power supply. The deposition temperature was 170℃, the deposition pressure was 0.5mbar, and the deposition power was 531W / m. 2 The hydrogen flow rate is 675 sccm, the silane flow rate is 150 sccm, the carbon dioxide flow rate is 50 sccm, and the flow rate of the diborane-hydrogen mixture is 500 sccm, with the diborane / silane flow rate doping ratio controlled at 6%. The buffer layer is made of boron-doped amorphous silicon oxide with a film thickness of 1-2 nm and a boron to silicon molar ratio of 2:15.

[0150] The surface of the buffer layer was treated with hydrogen plasma using a 40MHz VHF power supply. During the hydrogen plasma treatment, the hydrogen flow rate was 2400 sccm, the pressure was 0.7 mbar, and the power was 249 W / m³. 2 The time is 30 seconds.

[0151] A first transparent conductive layer with a thickness of 90 nm is deposited on the surface of the first transition layer by physical vapor deposition, and then the first electrode is screen printed.

[0152] A second transparent conductive layer with a thickness of 110 nm is deposited on the surface of the buffer layer by physical vapor deposition. Then, a second electrode is screen-printed to obtain a solar cell.

[0153] Example 2

[0154] The difference from Example 1 is that the material of the second seed layer is microcrystalline silicon oxide containing boron doped elements.

[0155] Example 3

[0156] The difference from Example 1 is that the material of the second seed layer is intrinsic microcrystalline silicon oxide.

[0157] Example 4

[0158] The difference from Example 1 is that the buffer layer is made of amorphous silicon with boron doping.

[0159] Example 5

[0160] Unlike Example 1, it does not have a buffer layer.

[0161] Example 6

[0162] The difference from Example 1 is that the doping ratios of phosphine and silane in the first seed layer, the first emitter layer, and the first transition layer are the same, and the molar ratio of phosphorus to silicon is 1:25.

[0163] Example 7

[0164] The difference from Example 1 is that it does not have a first transition layer and a second transition layer.

[0165] Example 8

[0166] The difference from Example 1 is that a 13.56MHz RF power supply was used instead of a VHF power supply in all film depositions.

[0167] Example 9

[0168] The difference from Example 1 is that the crystallization rate of the first seed layer is 0.3 and the crystallization rate of the first emission layer is 0.7.

[0169] Example 10

[0170] The difference from Example 1 is that the crystallization rate of the first seed layer is 0.6 and the crystallization rate of the first emission layer is 0.7.

[0171] Example 11

[0172] The difference from Example 1 is that the first seed layer is made of microcrystalline silicon carbide.

[0173] Example 12

[0174] The difference from Example 1 is that the second passivation layer is not treated with hydrogen plasma.

[0175] Example 13

[0176] The difference from Example 1 is that the molar ratio of phosphorus to silicon in the first seed layer is 1:10, and the molar ratio of boron to silicon in the second seed layer is 1:15.

[0177] Example 14

[0178] The difference from Example 1 is that the first passivation layer and the second passivation layer are not subjected to carbon dioxide plasma treatment, and the crystallization rate of the first seed layer is 0.2 and the crystallization rate of the second seed layer is 0.2.

[0179] Example 15

[0180] The difference from Example 1 is that the crystallization rate of the first seed layer is 0.2, the crystallization rate of the first emission layer is 0.8, the crystallization rate of the second seed layer is 0.8, and the crystallization rate of the second emission layer is 0.8.

[0181] Comparative Example 1

[0182] The difference from Example 1 is that it does not have a first seed layer, a second seed layer, a first transition layer, a second transition layer and a buffer layer, the first passivation layer and the second passivation layer are not treated with carbon dioxide plasma, the first emitter layer and the second emitter layer are both made of amorphous silicon, the crystallinity of the first emitter layer and the second emitter layer does not change and the crystallinity is below 0.1.

[0183] Comparative Example 2

[0184] The difference from Example 1 is that the first seed layer and the first emitter layer have the same crystallinity, and the second seed layer and the second emitter layer have the same crystallinity.

[0185] Comparative Example 3

[0186] The difference from Example 1 is that the first emitter layer and the second emitter layer do not include the first dopant element and the second dopant element.

[0187] Performance testing

[0188] The photovoltaic current-voltage characteristics of the solar cells prepared in Examples 1-15 and Comparative Examples 1-3 were tested according to the IEC 60904-1-2020 standard to obtain the open-circuit voltage (U). oc ), short-circuit current (I) sc ), fill factor (FF), photoelectric conversion efficiency (Eta), and maximum output power (P) mpp The results are shown in Table 1, where the open-circuit voltage (U) is... oc ): This refers to the voltage that a solar cell can generate when it is open-circuited, typically the theoretical maximum voltage of the cell; short-circuit current (I): sc The following parameters are considered: 1) Current: The current a solar cell can generate under no-load conditions; generally, it is the theoretical maximum current of the cell. 2) Fill factor (FF): The ratio of the cell's maximum output power to the product of its open-circuit voltage and short-circuit current. With a fixed open-circuit voltage and short-circuit current, a higher fill factor indicates higher cell conversion efficiency. 3) Photovoltaic conversion efficiency (Eta): The ratio of the solar cell's output power to the incident solar power under the corresponding conditions (Formula I). ​​This is the most important performance parameter of a solar cell, reflecting its ability to convert light energy into electrical energy. A higher Eta is better; it is generally taken as the ratio of maximum output power to incident solar power. 4) Maximum output power (P... mpp The voltage and current corresponding to reaching maximum output power are the maximum output voltage U. mpp and maximum output current I mpp ,

[0189]

[0190] The data obtained from photovoltaic current-voltage characteristic detection are normalized using the following formula:

[0191]

[0192] For example, if the conversion efficiency of a certain embodiment is 25.3% and the conversion efficiency of Comparative Example 1 is 25%, then the normalized conversion efficiency of this embodiment is 101.2%. Normalized data (open-circuit voltage (U...) oc ), short-circuit current (I) sc ), fill factor (FF), photoelectric conversion efficiency (Eta), and maximum output power (P) mpp As shown in Table 1.

[0193] Figure 13 This is a surface morphology image of the solar cell after coating, provided in Embodiment 1 of this application. Figure 14This is a surface morphology diagram of the solar cell after coating provided in Comparative Example 1 of this application. Example 1 and Comparative Example 1 use the same coating method. It can be seen by the naked eye or microscope that there are uneven particles / powder on the surface, resulting in a film bursting phenomenon.

[0194] Table 1. Photovoltaic current-voltage characteristic test results

[0195]

[0196] As can be seen from Examples 1-15 and Comparative Examples 1-3, the solar cell film provided in this application has suitable crystal quality, a low probability of film bursting, and high overall structural reliability. Simultaneously, each film layer in the solar cell has a strong carrier collection capacity, improving the open-circuit voltage, short-circuit current, and fill factor, further enhancing the photoelectric conversion efficiency of the solar cell. As can be seen from Examples 1-15, carbon dioxide plasma treatment, hydrogen plasma treatment, suitable preparation methods, suitable dopant element content, suitable film layer design, and suitable film layer material selection can all further improve the electrochemical performance and photoelectric conversion efficiency of the solar cell. As can be seen from Examples 1 and 13, further optimizing the ratio of dopant elements to silicon can improve the electrochemical performance of the solar cell. As can be seen from the examples and Comparative Examples 1-3, the presence of dopant elements and the formation of a molar ratio gradient between dopant elements and silicon in the solar cell can reduce interface defects and contact resistance, thereby improving the electrochemical performance of the solar cell.

[0197] The above description represents the preferred embodiments of this application, but should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

Claims

1. A solar cell, characterized in that, The solar cell includes a silicon substrate, a first film layer disposed on the surface of the silicon substrate, and a second film layer disposed on a side surface of the silicon substrate opposite to the first film layer. Along the direction from the silicon substrate to the first film layer, the first film layer includes a first passivation layer, a first emitter layer, and a first electrode layer stacked sequentially. The first passivation layer is connected to the surface of the silicon substrate. The crystallinity of the first emitter layer near the first electrode layer is greater than that of the first emitter layer near the silicon substrate. Along the direction from the silicon substrate to the first film layer, the first emitter layer includes a first seed layer and a first emitter body layer stacked together. The first seed layer is connected to the surface of the first passivation layer. The crystallinity of the first seed layer is 0.3-0.6, and the crystallinity of the first emitter body layer is greater than that of the first seed layer. Along the direction from the silicon substrate to the second film layer, the second film layer includes a second passivation layer, a second emitter layer, and a second electrode layer stacked sequentially. The second passivation layer is connected to the surface of the silicon substrate. The crystallinity of the second emitter layer near the second electrode layer is greater than that of the second emitter layer near the silicon substrate. Along the direction from the silicon substrate to the second film layer, the second emitter layer includes a second seed layer and a second emitter body layer stacked sequentially. The second seed layer is connected to the surface of the second passivation layer. The crystallinity of the second seed layer is 0.3-0.6, and the crystallinity of the second emitter body layer is greater than that of the second seed layer. The first emitter layer has a first doping element, which is a first doping type; The second emitter layer has a second doping element, which is a second doping type; The silicon substrate has either the first doping element or the second doping element, wherein the first doping element is different from the second doping element; The first seed layer has the first dopant element and silicon, and the second seed layer has the second dopant element and silicon. The molar ratio of the second dopant element to silicon in the second seed layer is greater than the molar ratio of the first dopant element to silicon in the first seed layer.

2. The solar cell as described in claim 1, characterized in that, The crystallinity of the first emission layer is 0.4-0.7; The material of the first seed layer includes at least one of microcrystalline silicon containing the first doping element, microcrystalline silicon carbide containing the first doping element, and microcrystalline silicon oxide containing the first doping element. The material of the first emission layer includes at least one of microcrystalline silicon containing the first doping element, microcrystalline silicon carbide containing the first doping element, and microcrystalline silicon oxide containing the first doping element. The crystallinity of the second emission layer is 0.4-0.7; The material of the second seed layer includes at least one of microcrystalline silicon containing the second doping element, microcrystalline silicon carbide containing the second doping element, and microcrystalline silicon oxide containing the second doping element. The material of the second emission layer includes at least one of microcrystalline silicon containing the second doping element, microcrystalline silicon carbide containing the second doping element, and microcrystalline silicon oxide containing the second doping element.

3. The solar cell as described in claim 1 or 2, characterized in that, The molar ratio of the first dopant element to silicon in the first emitter layer is greater than the molar ratio of the first dopant element to silicon in the first seed layer.

4. The solar cell as described in claim 1, characterized in that, The material of the first passivation layer includes at least one of amorphous silicon, amorphous silicon oxide, and silicon carbide, and the material of the second passivation layer includes at least one of amorphous silicon, amorphous silicon oxide, and silicon carbide.

5. The solar cell as described in claim 1, characterized in that, The first film layer further includes a first transition layer disposed between the first emission layer and the first electrode layer; The material of the first transition layer includes at least one of microcrystalline silicon containing the first doping element, microcrystalline silicon oxide containing the first doping element, and microcrystalline silicon carbide containing the first doping element.

6. The solar cell as described in claim 1, characterized in that, The second film layer further includes a second transition layer disposed between the second emission layer and the second electrode layer; The material of the second transition layer includes at least one of microcrystalline silicon containing the second doping element, microcrystalline silicon oxide containing the second doping element, and microcrystalline silicon carbide containing the second doping element.

7. The solar cell as described in claim 1, characterized in that, The second film layer further includes a buffer layer disposed between the second emission layer and the second electrode layer; The material of the buffer layer includes at least one of amorphous silicon containing the second doping element and amorphous silicon oxide containing the second doping element.

8. The solar cell as described in claim 1, characterized in that, The second film layer further includes a second transition layer and a buffer layer disposed between the second emission layer and the second electrode layer, wherein the second transition layer is disposed between the second emission layer and the buffer layer.

9. The solar cell as described in claim 1, characterized in that, The photoelectric conversion efficiency of the solar cell is greater than 25%.

10. A method for preparing a solar cell, characterized in that, include: A first film layer and a second film layer are deposited on a silicon substrate to obtain a solar cell. The solar cell includes a silicon substrate, a first film layer disposed on the surface of the silicon substrate, and a second film layer disposed on the surface of the silicon substrate facing away from the first film layer. Along the direction from the silicon substrate to the first film layer, the first film layer includes a first passivation layer, a first emitter layer, and a first electrode layer stacked sequentially. The first passivation layer is connected to the surface of the silicon substrate. The crystallinity of the first emitter layer near the first electrode layer is greater than the crystallinity of the first emitter layer near the silicon substrate. Along the direction from the silicon substrate to the first film layer, the first emitter layer includes a first seed layer and a first emitter body layer stacked together. The first seed layer is connected to the surface of the first passivation layer, and the crystallinity of the first seed layer is 0.

3. -0.6, the crystallinity of the first emitter layer is greater than the crystallinity of the first seed layer; along the direction from the silicon substrate to the second film layer, the second film layer includes a second passivation layer, a second emitter layer, and a second electrode layer stacked sequentially, the second passivation layer is connected to the surface of the silicon substrate, the crystallinity of the second emitter layer near the second electrode layer is greater than the crystallinity of the second emitter layer near the silicon substrate, along the direction from the silicon substrate to the second film layer, the second emitter layer includes a second seed layer and a second emitter layer stacked, the second seed layer is connected to the surface of the second passivation layer, the crystallinity of the second seed layer is 0.3-0.6, and the crystallinity of the second emitter layer is greater than the crystallinity of the second seed layer; the first emitter layer has a first doping element, which is a first doping type; The second emitter layer has a second doping element, which is a second doping type; The silicon substrate has either the first doping element or the second doping element, wherein the first doping element is different from the second doping element; The first seed layer has the first dopant element and silicon, and the second seed layer has the second dopant element and silicon. The molar ratio of the second dopant element to silicon in the second seed layer is greater than the molar ratio of the first dopant element to silicon in the first seed layer.

11. The preparation method according to claim 10, characterized in that, The process also includes carbon dioxide plasma treatment prior to the preparation of the first and / or second emission layers.

12. The preparation method according to claim 11, characterized in that, The carbon dioxide plasma treatment uses a flow rate of 50 sccm-200 sccm, a treatment time of 5 s-15 s, and a power of 66 W / m³. 2 -200W / m 2 .

13. A solar cell, characterized in that, The solar cell includes the solar cell according to any one of claims 1-9 or the solar cell prepared by the preparation method according to any one of claims 10-12.

14. An electrical appliance, characterized in that, The electrical device includes the solar cell as described in claim 13.

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