Magnesium fluoride film crystalline silicon photovoltaic cell, preparation method thereof and electric equipment

Abstract

The invention provides a magnesium fluoride film crystalline silicon photovoltaic cell, a preparation method thereof and an electric device, and belongs to the technical field of photovoltaic cells. The magnesium fluoride thin film crystalline silicon photovoltaic cell structurally comprises a back metal electrode layer, a back SiNx passivation layer, a tunneling poly phosphorus-doped amorphous silicon layer, an N-si silicon substrate, a P + emitter layer, a positive SiNx passivation layer, a magnesium fluoride thin film and a front metal electrode layer from bottom to top in sequence. According to the magnesium fluoride thin film crystalline silicon photovoltaic cell provided by the invention, the magnesium fluoride thin film is newly added on the surface of the aluminum oxide, so that recombination of charges at an interface is effectively prevented, the service life of minority carriers is prolonged, charge transmission is enhanced, open-circuit current is improved, and a back surface field passivation effect is optimized. Besides, through optimization of a coating technology, a layer of magnesium fluoride film is additionally arranged on the front surface and the back surface, so that the conversion efficiency of the cell is remarkably improved under the condition that the manufacturing cost is not increased, and the performance is remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of photovoltaic cells, and particularly relates to a magnesium fluoride thin film crystalline silicon photovoltaic cell and a preparation method thereof and an electrical device. BACKGROUND

[0002] As a technology for directly converting solar energy into electrical energy, photovoltaic cells are increasingly becoming an important means to solve global energy problems due to their advantages of being renewable, clean, and efficient. The core component of a photovoltaic cell is a photoelectric conversion thin film, and the quality and performance of the thin film directly affect the conversion efficiency and service life of the cell. Therefore, research and improvement of the preparation technology of the photovoltaic cell thin film is of great significance to improve the overall performance of the photovoltaic cell.

[0003] Currently, the mainstream photovoltaic cell thin film preparation technology adopts PECVD, i.e. "plasma-enhanced chemical vapor deposition". PECVD is a chemical vapor deposition technology that uses microwaves to ionize a gas containing thin film component atoms (such as Si, N), forming a local plasma. Due to the high chemical activity of the plasma, a Si x N y Silicon nitride thin film is widely used in photovoltaic cells and has become an important choice for photovoltaic cell thin film materials due to its good photoelectric performance and stability.

[0004] However, the application of silicon nitride thin film in photovoltaic cells has also exposed some defects, affecting the overall performance of the cell. First, the high refractive index of silicon nitride thin film can easily lead to increased light reflection, reducing the amount of light entering the interior of the cell, thereby reducing the photoelectric conversion efficiency. Second, silicon nitride thin film may develop pinholes and cracks during long-term use, affecting the sealing performance of the thin film and thus affecting the weather resistance and service life of the cell. In addition, impurities may be introduced during the preparation of silicon nitride thin film, which can become defect centers inside the cell, affecting the stability and output performance of the cell.

[0005] In summary, although PECVD technology plays an important role in the preparation of silicon nitride thin film, the problems of high refractive index, easy formation of defects and impurities seriously restrict the improvement of the performance of photovoltaic cells. Therefore, how to overcome these defects of silicon nitride thin film and seek more optimized thin film materials and preparation processes has become an important direction for research on photovoltaic cell technology. SUMMARY

[0006] To solve the above problems, the present application provides a magnesium fluoride thin film crystalline silicon photovoltaic cell, the structure of the magnesium fluoride thin film crystalline silicon photovoltaic cell sequentially comprises from bottom to top:

[0007] a back metal electrode layer, a back SiN xPassivation layer, tunneling poly-phosphorus doped amorphous silicon layer, N-si silicon substrate, P + Emitting layer, positive SiN x Passivation layer, magnesium fluoride film and positive metal electrode layer;

[0008] Preferably, the N-si silicon substrate is an N-type original silicon wafer;

[0009] Preferably, the P + The emitting layer is obtained by doping positive trivalent boron externally;

[0010] Preferably, the tunneling poly-phosphorus doped amorphous silicon layer is prepared by depositing a layer of amorphous silicon on the surface of silicon dioxide, and then high-temperature phosphorus diffusion;

[0011] Preferably, the SiN x The passivation layer is obtained by sequentially depositing aluminum oxide and silicon oxynitride;

[0012] Preferably, the positive metal electrode layer and the back metal electrode layer are obtained by screen printing metal paste.

[0013] In addition, to solve the above problems, the application also provides a preparation method of the magnesium fluoride film crystalline silicon photovoltaic cell as described above, comprising:

[0014] The N-type original silicon wafer is subjected to etching and cleaning treatment to obtain an N-si silicon substrate with a positive metal grid line area on the front surface;

[0015] The metal grid line area on the front surface of the N-si silicon substrate is subjected to boron diffusion treatment to form a P + emitting layer on the front surface of the N-si silicon substrate;

[0016] The back surface of the N-si silicon substrate is subjected to alkaline polishing treatment, and the surface of the polished N-si silicon substrate is subjected to tunneling phosphorus poly treatment to obtain a tunneling poly-phosphorus doped amorphous silicon layer of the N-si silicon substrate, which constitutes a passivation cell;

[0017] The front surface of the N-si silicon substrate of the passivation cell is subjected to etching treatment to form a polished surface structure on the front surface of the N-si silicon substrate of the passivation cell;

[0018] The back SiN x passivation layer and positive SiN x passivation layer are prepared for the passivation cell respectively; x The magnesium fluoride film is prepared on the basis of the passivation layer and the positive SiN

[0019] The silver paste is used for metallization treatment and laser sintering treatment to form a back metal electrode layer and a positive metal electrode layer, thereby obtaining the magnesium fluoride film crystalline silicon photovoltaic cell.

[0020] Preferably, the texturing cleaning treatment on the N-type original silicon wafer obtains the N-si silicon substrate with the metal gate line area on the front side, comprising:

[0021] The N-type original silicon wafer is sequentially subjected to the pre-cleaning treatment, the alkali solution texturing treatment and the post-cleaning treatment in the texturing cleaning treatment, to obtain the N-si silicon substrate with the metal gate line area on the front side;

[0022] Preferably, the cleaning solution of the pre-cleaning treatment is a mixed solution of HCl and H2O2;

[0023] Preferably, the mass ratio of the mixed solution of HCl and H2O2 is 0.2%-0.5%;

[0024] Preferably, the cleaning solution of the alkali solution texturing treatment is NaOH or KOH;

[0025] Preferably, the mass ratio of the cleaning solution of the alkali solution texturing treatment is 0.4%-1.3%;

[0026] Preferably, the cleaning solution of the post-cleaning treatment is an HF solution;

[0027] Preferably, the mass ratio of the HF solution is 0.1%-0.3%;

[0028] Preferably, the texturing time of the texturing cleaning treatment is 40 minutes-60 minutes.

[0029] Preferably, the screening conditions of the N-type original silicon wafer include:

[0030] The resistivity ranges from 0.8Ω·cm to 1.5Ω·cm;

[0031] The minority carrier lifetime is greater than 1000μs;

[0032] The cell thickness is 100μm-180μm.

[0033] Preferably, the boron source of the boron diffusion treatment includes at least one of boron tribromide and boron trichloride;

[0034] The process conditions of the boron diffusion treatment include:

[0035] The temperature is 900℃-1000℃;

[0036] The square resistance is 350Ω-500Ω;

[0037] The doping concentration is 1×10 18 -1×10 19 ;

[0038] The PN junction depth is 0.7-0.8 μm.

[0039] Preferably, the back surface of the N-si silicon substrate is subjected to the alkaline polishing treatment, comprising:

[0040] The back surface of the N-si silicon substrate is subjected to the pre-cleaning, alkaline solution treatment and acid solution treatment in the alkaline polishing treatment in sequence;

[0041] Preferably, the cleaning solution of the pre-cleaning in the alkaline polishing treatment is a mixed solution of NaOH and H2O2 or a mixed solution of KOH and H2O2;

[0042] Preferably, the mass ratio of the cleaning solution of the pre-cleaning in the alkaline polishing treatment is 0.3%-0.5%;

[0043] Preferably, the cleaning solution of the alkaline solution treatment in the alkaline polishing treatment is a NaOH solution or a KOH solution;

[0044] Preferably, the mass ratio of the cleaning solution of the alkaline solution treatment in the alkaline polishing treatment is 4%-12%;

[0045] Preferably, the cleaning solution of the acid solution treatment in the alkaline polishing treatment is an HF solution or an HCl solution;

[0046] Preferably, the mass ratio of the cleaning solution of the acid solution treatment in the alkaline polishing treatment is 3%-10%;

[0047] Preferably, the time of the alkaline polishing treatment is 30-60 minutes.

[0048] Preferably, the surface of the polished N-si silicon substrate is subjected to the tunneling phosphorus poly treatment, comprising:

[0049] The surface of the polished N-si silicon substrate is subjected to a deposition treatment;

[0050] Then, a high-temperature tube-type thermal decomposition POCI3 technology is used for phosphorus doping treatment to obtain a tunneling poly phosphorus-doped amorphous silicon layer on the surface of the N-si silicon substrate;

[0051] Preferably, in the deposition treatment, the thickness of the tunneling oxide layer is 1-3 nm, the thickness of the amorphous silicon layer is 100-200 nm, and the reactant of the deposition treatment is silane;

[0052] Preferably, the temperature of the phosphorus doping treatment is 600-800 °C;

[0053] Preferably, the phosphorus deposition time of the phosphorus doping treatment is 5-7 minutes;

[0054] Preferably, the phosphorus doping treatment has a phosphorus diffusion resistance of 40-60 ohms, and a concentration of 3x10 19 -4x10 20 .

[0055] Preferably, the etching treatment on the front surface of the N-si silicon substrate to form the polished surface structure of the front surface of the N-si silicon substrate of the passivated battery comprises:

[0056] acid pickling treatment of the front surface of the N-si silicon substrate with an acidic solution;

[0057] the front surface etching treatment of the passivated battery to form the polished surface structure of the front surface of the N-si silicon substrate of the passivated battery;

[0058] Preferably, in the acid pickling treatment, the acidic solution is HF or HNO3;

[0059] Preferably, the mass ratio of the acidic solution is 5%-15%;

[0060] Preferably, the alkaline solution of the front surface etching treatment is NaOH or KOH;

[0061] Preferably, the mass ratio of the alkaline solution of the front surface etching treatment is 5%-10%;

[0062] Preferably, the front surface etching treatment time is 40-60 minutes.

[0063] Preferably, the preparation of the magnesium fluoride film inside the passivated battery comprises:

[0064] depositing an aluminum oxide layer on the passivated battery using atomic layer deposition (ALD) technology;

[0065] depositing the front SiN x passivation layer and the back SiN x passivation layer using PECVD technology, respectively; x Preferably, the front SiN x passivation layer comprises three layers of silicon nitride, two layers of silicon oxynitride, and one layer of silicon oxide; and the back SiN

[0066] Preferably, the magnesium fluoride film is deposited on the basis of the front SiN x passivation layer;

[0067] Preferably, the thickness of the aluminum oxide layer is 3-5 nm;

[0068] Preferably, the process temperature of the atomic layer deposition (ALD) technology is 200-300°C;

[0069] Preferably, the deposition time of the atomic layer deposition ALD technology is 20-30 minutes.

[0070] Preferably, the back SiN x Preferably, the thickness of the passivation layer and the front SiN x Preferably, the thickness of the passivation layer and the front SiN

[0071] Preferably, the process temperature of the physical vapor deposition PECVD technology is 400-550 DEG C.

[0072] Preferably, the deposition time of the physical vapor deposition PECVD technology is 15-25 minutes.

[0073] Preferably, the thickness of the magnesium fluoride thin film is 5-15 nm.

[0074] Preferably, the process temperature of the magnesium fluoride thin film is 350-500 DEG C.

[0075] In addition, to solve the above problems, the application also provides an electrical equipment, which comprises the magnesium fluoride thin film crystalline silicon photovoltaic cell as described above.

[0076] The application provides a magnesium fluoride thin film crystalline silicon photovoltaic cell, a preparation method thereof and an electrical equipment. The magnesium fluoride thin film crystalline silicon photovoltaic cell comprises, from bottom to top, a back metal electrode layer, a SiN x passivation layer, a tunneling poly phosphorus-doped amorphous silicon layer, an N-si silicon substrate, a P + emitter layer, a SiN x passivation layer, a magnesium fluoride thin film and a front metal electrode layer. The magnesium fluoride thin film crystalline silicon photovoltaic cell has the following beneficial effects:

[0077] By adding a magnesium fluoride thin film on the surface of aluminum oxide, the recombination of charges at the interface is effectively prevented, the lifetime of minority carriers is improved, the transmission of charges is enhanced, the open circuit current is improved, and the effect of back passivation is optimized.

[0078] The application optimizes the coating technology, improves the conversion efficiency of the cell by adding a magnesium fluoride thin film on the front / back surface, and improves the performance in a considerable manner without increasing the manufacturing cost. BRIEF DESCRIPTION OF DRAWINGS

[0079] Figure 1 Fig. 1 is a structure schematic diagram of a magnesium fluoride thin film crystalline silicon photovoltaic cell in an embodiment of the application;

[0080] Figure 2 Fig. 2 is a flow schematic diagram of a preparation method of a magnesium fluoride thin film crystalline silicon photovoltaic cell in an embodiment of the application.

[0081] Reference signs:

[0082] 100, fluorinated magnesium thin film crystal silicon photovoltaic cell; 1, back metal electrode layer; 2, back SiN x passivation layer; 3, tunneling poly phosphorus doped amorphous silicon layer; 4, N-si silicon substrate; 5, P + emitter layer 6, positive SiN x passivation layer; 7, fluorinated magnesium thin film; 8, front metal electrode layer. DETAILED DESCRIPTION

[0083] The technical solutions of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0084] Reference Figure 1 In the embodiments of the present application, a fluorinated magnesium thin film crystal silicon photovoltaic cell is provided, and the structure of the fluorinated magnesium thin film crystal silicon photovoltaic cell comprises, from bottom to top, in sequence:

[0085] back metal electrode layer, back SiN x passivation layer, tunneling poly phosphorus doped amorphous silicon layer, N-si silicon substrate, P + emitter layer, positive SiN x passivation layer, fluorinated magnesium thin film and front metal electrode layer;

[0086] Further, the N-si silicon substrate is an N-type original silicon wafer;

[0087] Further, the P + emitter layer is obtained by doping positive trivalent boron externally;

[0088] Further, the tunneling poly phosphorus doped amorphous silicon layer is prepared by depositing a layer of amorphous silicon on the surface of silicon dioxide, and then obtaining by high-temperature phosphorus diffusion;

[0089] Further, the SiN x passivation layer is obtained by sequentially depositing aluminum oxide and silicon oxynitride;

[0090] Further, the front metal electrode layer and the back metal electrode layer are obtained by screen printing metal paste.

[0091] The backside metal electrode layer, as the cathode of the photovoltaic cell, collects and transports current. The use of metal materials (such as silver, aluminum, etc.) can provide good electrical conductivity and low resistance, thereby improving the fill factor and overall efficiency of the cell. The frontside metal electrode layer, as the anode of the photovoltaic cell, collects and transports current. The metal electrode layer prepared by screen printing technology can provide good electrical conductivity and mechanical stability, and is easy to mass-produce, reducing manufacturing costs.

[0092] The frontside metal electrode layer and the backside metal electrode layer are obtained by screen printing metal paste. Screen printing technology can accurately control the pattern and thickness of the metal electrode, providing low resistance contact and good mechanical stability, while having the advantages of high production efficiency and low cost.

[0093] The backside SiN x The passivation layer passivates the surface defects on the backside, reduces carrier recombination, and improves the lifetime of minority carriers. Through the application of the passivation layer, the open-circuit voltage and overall efficiency of the photovoltaic cell can be significantly improved. The frontside SiN x The passivation layer is used to passivate the surface defects on the frontside, reduce the recombination of photo-generated carriers, and improve the lifetime of minority carriers. The SiN x The excellent antireflection performance and passivation effect of the SiN

[0094] The SiN x The passivation layer is obtained by sequentially depositing aluminum oxide and silicon oxynitride. The multilayer structure of the SiN x The passivation layer can provide excellent surface passivation effect and antireflection performance, further reducing surface recombination and improving the efficiency of the photovoltaic cell.

[0095] The tunneling poly-phosphorus-doped amorphous silicon layer forms a good tunneling contact on the backside, promoting the effective transport of carriers. The high electrical conductivity of amorphous silicon and the n-type characteristics provided by phosphorus doping can achieve excellent charge transport performance and low resistance contact. The high electrical conductivity of amorphous silicon and the n-type characteristics provided by phosphorus doping, combined with the insulating properties of silicon dioxide, help to form a good tunneling contact and improve the efficiency of charge transport.

[0096] The N-si silicon substrate, as the main body of the photovoltaic cell, provides the main area for photoelectric conversion. The N-type silicon wafer has high minority carrier lifetime and good electrical properties, which can improve the overall efficiency and reliability of the photovoltaic cell. The N-type silicon wafer provides high electron mobility and minority carrier lifetime, which helps to improve the photoelectric conversion efficiency and long-term stability of the photovoltaic cell.

[0097] The P +The emitter layer is used to form a PN junction, which provides p-type characteristics by doping with trivalent boron, and facilitates the separation and collection of photo-generated carriers. P + The high doping concentration and good electrical properties of the emitter layer help to improve the short-circuit current and open-circuit voltage of the photovoltaic cell. Among them, P + The emitter layer is formed by doping trivalent boron, which can optimize the electrical properties of the PN junction, improve the separation efficiency of photo-generated carriers, and thus increase the short-circuit current and open-circuit voltage.

[0098] As mentioned above, the magnesium fluoride film, as a transparent conductive layer and anti-reflection layer, enhances the transmission of incident light and reduces reflection loss. The low refractive index and high transparency of the magnesium fluoride film can significantly improve the light absorption efficiency of the photovoltaic cell, thereby improving the conversion efficiency of the cell.

[0099] In summary, the magnesium fluoride film crystalline silicon photovoltaic cell provided in the embodiments of the present application has significant beneficial effects: by adding a layer of magnesium fluoride film on the surface of aluminum oxide, the recombination of charges at the interface is effectively prevented, the lifetime of minority carriers is improved, the charge transport is enhanced, the open-circuit current is improved, and the back field passivation effect is optimized. In addition, by optimizing the plating technology, a layer of magnesium fluoride film is added on the front and back surfaces, which significantly improves the conversion efficiency of the cell without increasing the manufacturing cost, and significantly improves the performance.

[0100] In addition, with reference to Figure 2 The present application also provides a preparation method of the magnesium fluoride film crystalline silicon photovoltaic cell as described above, comprising:

[0101] Step S1: performing texturing and cleaning treatment on the N-type original silicon wafer to obtain an N-si silicon substrate with a metal grid line region on the front surface;

[0102] As mentioned above, the texturing and cleaning treatment is a process for surface treatment of silicon wafers in the manufacturing process of photovoltaic cells. The main purpose is to form a small pyramid structure (i.e. textured surface) on the surface of the silicon wafer to enhance the light trapping capability, and at the same time remove the surface oxides and other impurities.

[0103] As mentioned above, in step S1, the N-type original silicon wafer is subjected to texturing and cleaning treatment to obtain an N-si silicon substrate with a metal grid line region on the front surface. The "metal grid line region" here refers to a pre-defined area where metal grid electrodes will be formed in subsequent steps. The metal grid is used to collect and conduct photo-generated current, and is an important part of the photovoltaic cell.

[0104] Among them, the metal grid line region refers to a specific area reserved on the silicon substrate, where metal grid lines will be deposited in subsequent processes. These grid lines are usually made of highly conductive metals such as silver or aluminum, which are used to collect the current generated by the photovoltaic cell and conduct it to the external circuit.

[0105] Step S2, boron diffusion treatment is performed on the metal gate line area on the front surface of the N-si silicon substrate to form a P + emitter layer on the front surface of the N-si silicon substrate.

[0106] In the above, in the boron diffusion treatment on the metal gate line area on the front surface of the N-si silicon substrate, boron tribromide (BBr3) or boron trichloride (BCl3) is used for high-temperature diffusion to make boron atoms penetrate into the silicon substrate to form a P + emitter layer, a good PN junction is formed, and the separation efficiency of photo-generated carriers is improved, and the open-circuit voltage and short-circuit current of the photovoltaic cell are improved.

[0107] Step S3, alkaline polishing treatment is performed on the back surface of the N-si silicon substrate, and tunneling polyphosphorus doped amorphous silicon layer is prepared on the surface of the polished N-si silicon substrate to form a passivated cell.

[0108] In the above, the back surface of the N-si silicon substrate is polished with an alkaline solution to remove surface impurities and oxides, and amorphous silicon layer is prepared on the surface of the silicon dioxide by deposition technology, and then high-temperature phosphorus diffusion is performed to form the tunneling polyphosphorus doped amorphous silicon layer.

[0109] In the above, the alkaline polishing improves the flatness of the back surface, which is beneficial to the deposition of the subsequent layers. The tunneling polyphosphorus doped amorphous silicon layer provides good passivation effect and low resistance contact, and improves the cell efficiency.

[0110] Step S4, etching treatment is performed on the front surface of the N-si silicon substrate to form a polished surface structure on the front surface of the N-si silicon substrate of the passivated cell.

[0111] In the above, the front surface of the passivated cell is etched to form a polished surface structure, and specifically, the front surface can be etched with an acidic or alkaline solution to remove unnecessary materials on the surface, thereby obtaining the polished surface structure on the front surface of the N-si silicon substrate. In this step, the smoothness of the front surface is improved, the surface defects are reduced, and the light incidence and absorption are enhanced.

[0112] Step S5, back SiN x passivation layer and front SiN x passivation layer are prepared on the passivated cell, respectively. x fluorine-doped magnesium film is prepared on the basis of the front SiN

[0113] In the above, back SiN x passivation layer and front SiN xThe passivation layer is prepared on the basis of the positive SiNx passivation layer, and a magnesium fluoride film is prepared on the basis of the positive SiNx passivation layer. The SiNx passivation layer is deposited by using a gas phase deposition (PECVD) technology.

[0114] The magnesium fluoride film can be deposited on the basis of the SiNx passivation layer by using a gas phase deposition or pulse laser deposition technology, so that the SiNx passivation layer and the magnesium fluoride film with excellent anti-reflection and passivation effects are formed.

[0115] The SiNx passivation layer provides excellent surface passivation effects and reduces carrier recombination. The magnesium fluoride film has low refractive index and high transparency, enhances light transmission, and improves cell efficiency.

[0116] The magnesium fluoride crystal has good optical performance, mechanical performance, and chemical stability, is a very important optical functional crystal material, and is widely used. The magnesium fluoride crystal is often used to prepare a magnesium fluoride film.

[0117] There are several important reasons for using the magnesium fluoride crystal to prepare the magnesium fluoride film in the photovoltaic cell:

[0118] The magnesium fluoride (MgF2) film has a relatively low refractive index, usually between 1.38 and 1.45. This low refractive index makes it an excellent anti-reflection coating material, which can significantly reduce light reflection loss and improve the absorption efficiency of incident light in the photovoltaic cell, thereby improving the overall conversion efficiency of the cell.

[0119] The magnesium fluoride film has excellent transparency and can effectively transmit most of the light in the spectral range, especially in the ultraviolet and visible light regions. This property makes it very suitable as a cover layer for photovoltaic cells, maximizing the amount of light entering the photovoltaic cell, thereby enhancing the photoelectric conversion efficiency.

[0120] The magnesium fluoride film also has certain electrical conductivity, which can play a role in electron conduction in the photovoltaic cell. By adding a layer of magnesium fluoride film on the surface of aluminum oxide, the charge recombination at the interface can be effectively prevented, the lifetime of minority carriers can be improved, the charge transport can be enhanced, the open-circuit current can be improved, and the back field passivation effect can be optimized.

[0121] The magnesium fluoride film has good chemical stability and corrosion resistance under environmental conditions and is not easily affected by the external environment, and can maintain long-term stability. This is very important for the long-term use and stable operation of the photovoltaic cell.

[0122] The magnesium fluoride crystal has good mechanical strength and wear resistance, which makes the magnesium fluoride film maintain integrity and stability during the production and use of the photovoltaic cell, and reduces the performance degradation caused by mechanical damage.

[0123] By optimizing the coating technology, adding magnesium fluoride film on the front and back, the conversion efficiency of photovoltaic cells can be significantly improved without increasing the manufacturing cost. This process optimization brings considerable performance improvement, making magnesium fluoride film an economical and efficient choice.

[0124] In summary, the use of magnesium fluoride crystal in the preparation of magnesium fluoride film in photovoltaic cells is to take advantage of its low refractive index, high transparency, good electrical properties, chemical stability and mechanical properties to significantly improve the photoelectric conversion efficiency and long-term stability of photovoltaic cells while maintaining the cost economy.

[0125] Step S6, using silver paste for metallization and laser sintering treatment, forming back metal electrode layer and front metal electrode layer, i.e. the magnesium fluoride film silicon photovoltaic cell is obtained.

[0126] As mentioned above, the silver paste is used for metallization and laser sintering to form the back and front metal electrode layer. Specifically, the silver paste can be applied to the surface of the silicon wafer by screen printing technology to form the electrode pattern. The silver paste is sintered using laser sintering technology to form a metal electrode with good conductivity, thereby forming the back metal electrode layer and the front metal electrode layer, completing the structure of the photovoltaic cell.

[0127] In the above steps, the silver paste provides excellent conductivity and low resistance contact. Laser sintering technology can accurately control energy and time to improve the quality and stability of the metal electrode.

[0128] In the above steps, the metallization process can use screen printing or other printing technology to apply silver paste to the front surface of the silicon wafer to form a predetermined electrode pattern, prepare the front and back electrodes of the cell and the electric field to achieve the purpose of collecting and transporting charge carriers.

[0129] It should be noted that the silver paste contains silver particles, organic solvents and adhesives, and the metal paste includes silver, aluminum and copper.

[0130] Before laser treatment, the silver paste coated silicon wafer is pre-dried to remove most of the organic solvents to avoid gas bubbles generated by laser heating affecting the contact quality. The battery is subjected to 780-9 selection at 00℃ high temperature sintering annealing treatment to form a silver-aluminum alloy layer and good ohmic contact to improve the fill factor of the battery.

[0131] As mentioned above, laser sintering can be LECO laser sintering. Specifically, the laser can be precisely controlled in energy and irradiation time, and the laser is irradiated on the silver paste to locally heat the silver paste for sintering. The thermal effect of the laser induces the melting and connection of silver particles in the silver paste, thereby preparing the final product, i.e. the magnesium fluoride film silicon photovoltaic cell.

[0132] Further, the step S1, the N-type original silicon wafer is prepared for the cleaning treatment, the N-si silicon substrate with the front surface having the metal gate line area is obtained, comprising:

[0133] The step S11, the N-type original silicon wafer is prepared for the cleaning treatment, the N-si silicon substrate with the front surface having the metal gate line area is obtained, comprising:

[0134] Further, the cleaning solution of the pre-cleaning treatment is HCl and H2O2 mixed solution;

[0135] Further, the mass ratio of the HCl and H2O2 mixed solution is 0.2%-0.5%; for example, it can be 0.2%, 0.3%, 0.4%, 0.5% and the like.

[0136] Further, the cleaning solution of the alkali solution texturing treatment is NaOH or KOH;

[0137] Further, the mass ratio of the cleaning solution of the alkali solution texturing treatment is 0.4%-1.3%; for example, it can be 0.4%, 0.6%, 0.8%, 1.0%, 1.1%, 1.3% and the like.

[0138] Further, the cleaning solution of the post-cleaning treatment is HF solution;

[0139] Further, the mass ratio of the HF solution is 0.1%-0.3%; for example, it can be 0.1%, 0.2%, 0.3% and the like.

[0140] Further, the texturing time of the texturing cleaning treatment is 40 minutes-60 minutes. For example, it can be 40 minutes, 50 minutes, 60 minutes and the like.

[0141] Further, the screening conditions of the N-type original silicon wafer include:

[0142] The resistivity range is 0.8Ω·cm-1.5Ω·cm; for example, it can be 0.8Ω·cm, 0.9Ω·cm, 1.0Ω·cm, 1.3Ω·cm, 1.5Ω·cm and the like.

[0143] The minority carrier lifetime is greater than 1000μs;

[0144] The cell thickness is 100μm-180μm. For example, it can be 100μm, 120μm, 140μm, 160μm, 180μm and the like.

[0145] The above, first can carry out the single crystal N type raw silicon wafer screening, its screening standard is resistivity range in 0.8 Ω·cm-1.5 Ω·cm;Minority carrier lifetime is greater than 1000 μs;Battery thickness is in 100 μm-180 μm.

[0146] Then, using acid, base solution removes the mechanical damage layer and metal ions on the surface of single crystal N type raw silicon wafer, and forms "pyramid" appearance on the battery surface, improves the light trapping effect of the battery, and the texturing process includes pre-cleaning, alkali solution texturing and post-cleaning.

[0147] Among them, pre-cleaning is carried out in the pre-cleaning tank, and the cleaning solution can be HCl, H2O2 mixed solution, and the mass ratio of the solution is 0.2-0.5%;

[0148] The alkali solution texturing tank is used for alkali solution texturing treatment, and the cleaning solution can be NaOH or KOH, and the mass ratio of the solution is 0.4-1.3%.

[0149] The post-cleaning tank is used for post-cleaning treatment, and the cleaning solution is HF solution with a mass ratio of 0.1-0.3%.

[0150] The above texturing time is 40-60 min.

[0151] Further, in the step S2, the boron source of the boron diffusion treatment includes at least one of boron tribromide and boron trichloride;

[0152] The process conditions of the boron diffusion treatment include:

[0153] The temperature is 900-1000 DEG C; for example, it can be 900 DEG C, 950 DEG C, 1000 DEG C, etc.

[0154] The square resistance is 350-500 ohms; for example, it can be 350 ohms, 400 ohms, 450 ohms, 500 ohms, etc.

[0155] The doping concentration is 1×10 18 -1×10 19 ;

[0156] The PN junction depth is 0.7-0.8 μm. For example, it can be 0.7 μm, 0.75 μm, 0.8 μm, etc.

[0157] The above step is to prepare a poly layer passivation structure in the battery front metal grid line area, and the boron source includes boron tribromide (BBr3) and boron trichloride (BCl3), forming a poly / boron-doped amorphous silicon passivation structure.

[0158] The temperature is 900-1000 DEG C, the boron deposition time is 5-7 min. The process requires a square resistance of 350-500 ohms, a concentration of 1e18-1e19, and a junction depth of 0.7-0.8 μm.

[0159] Further, the step S3 of performing the alkaline polishing treatment on the back surface of the N-si silicon substrate comprises:

[0160] The step S31 of sequentially performing the pre-cleaning, the alkaline solution treatment and the acid solution treatment in the alkaline polishing treatment on the back surface of the N-si silicon substrate comprises:

[0161] Further, the cleaning solution for the pre-cleaning in the alkaline polishing treatment is a mixed solution of NaOH and H2O2 or a mixed solution of KOH and H2O2.

[0162] Further, the mass ratio of the cleaning solution for the pre-cleaning in the alkaline polishing treatment is 0.3-0.5%; for example, it can be 0.3%, 0.4%, 0.5%, etc.

[0163] Further, the cleaning solution for the alkaline solution treatment in the alkaline polishing treatment is a NaOH solution or a KOH solution.

[0164] Further, the mass ratio of the cleaning solution for the alkaline solution treatment in the alkaline polishing treatment is 4-12%; for example, it can be 4%, 5%, 8%, 10%, 11%, 12%, etc.

[0165] Further, the cleaning solution for the acid solution treatment in the alkaline polishing treatment is an HF solution or an HCl solution.

[0166] Further, the mass ratio of the cleaning solution for the acid solution treatment in the alkaline polishing treatment is 3-10%; for example, it can be 3%, 5%, 8%, 10%, etc.

[0167] Further, the time for the alkaline polishing treatment is 30-60 min; for example, it can be 30 min, 40 min, 50 min, 60 min, etc.

[0168] In the above steps, a tank cleaning device can be used to polish the back surface of the boron-doped cell, and the main process can be pre-cleaning, alkaline solution, and acid solution in sequence.

[0169] The pre-cleaning tank is used for pre-cleaning, and the cleaning solution is a mixed solution of NaOH and H2O2 or a mixed solution of KOH and H2O2, and the mass ratio of the solution is 0.3-0.5%.

[0170] The alkali solution treatment is performed in an alkali solution etching tank, and the cleaning solution is NaOH or KOH with a mass ratio of 4-12%.

[0171] The acid solution treatment is performed in an acid solution tank, and the cleaning solution is HF or HCL solution with a mass ratio of 3-10%. The backside alkali polishing time is 30-60 min.

[0172] Further, the step S3 of performing tunneling phosphorus poly treatment on the polished N-si silicon substrate surface comprises:

[0173] Step S32, depositing treatment is performed on the polished N-si silicon substrate surface;

[0174] Step S33, then high-temperature tube type thermal decomposition POCI3 technology is used for phosphorus doping treatment to obtain a tunneling poly phosphorus-doped amorphous silicon layer on the N-si silicon substrate surface.

[0175] Further, in the deposition treatment, the thickness of the tunneling oxide layer is 1-3 nm, and the thickness of the amorphous silicon layer is 100-200 nm. The reactant of the deposition treatment is silane.

[0176] Further, the temperature of the phosphorus doping treatment is 600-800℃; for example, it can be 600℃, 700℃, 800℃, etc.

[0177] Further, the phosphorus deposition time of the phosphorus doping treatment is 5-7 minutes; for example, it can be 5 minutes, 6 minutes, 7 minutes, etc.

[0178] Further, the phosphorus doping treatment has a phosphorus diffusion resistance of 40-60 ohms, and the concentration is 3×10 19 -4×10 20 .

[0179] In the above steps, the poly layer passivation structure is prepared in the backside area of the battery, and the deposition technology can include LPCVD, PECVD, and ALD.

[0180] LPCVD: Low Pressure Chemical Vapor Deposition, a chemical vapor deposition technology performed in a low-pressure environment, which deposits a thin film on the substrate through a chemical reaction. LPCVD is commonly used to deposit silicon oxide, silicon nitride, polysilicon, etc.

[0181] PECVD: Plasma Enhanced Chemical Vapor Deposition, a technology that uses plasma to promote chemical reactions, thereby depositing thin films at lower temperatures. PECVD is commonly used to deposit insulating films, semiconductor films, and hard masks, etc.

[0182] ALD: Atomic Layer Deposition, a technology that deposits thin films layer by layer, with the thickness of each layer controlled to atomic level. ALD technology achieves uniform deposition of thin films through chemical adsorption and surface saturation reactions, commonly used to deposit high-k dielectrics, metals, and metal oxides, etc.

[0183] The tunnel oxide layer is deposited to a thickness of 1-3 nm, and the amorphous silicon layer is deposited to a thickness of 100-200 nm, with silane (SiH4) as the reactant; then, phosphorus diffusion is performed, and the cell is phosphorus-doped using high-temperature tubular thermal decomposition POCI3 technology, forming a poly / phosphorus-doped amorphous silicon passivation structure, with a temperature of 600-800°C and a phosphorus deposition time of 5-7 min.

[0184] The phosphorus diffusion resistor is 40 ohms-60 ohms, with a concentration of 3e19-4e20.

[0185] Further, the step S4, etching treatment is performed on the front surface of the N-si silicon substrate to form a polished surface structure on the front surface of the N-si silicon substrate of the passivated cell, comprising:

[0186] Step S41, acid pickling treatment is performed on the front surface of the N-si silicon substrate using an acidic solution;

[0187] Step S42, front surface etching treatment is performed on the passivated cell to form a polished surface structure on the front surface of the N-si silicon substrate of the passivated cell;

[0188] Further, in the pickling treatment, the acidic solution is HF or HNO3;

[0189] Further, the mass ratio of the acidic solution is 5%-15%; for example, it can be 5%, 7%, 10%, 13%, 15%, etc.

[0190] Further, the alkaline solution for front surface etching treatment is NaOH or KOH;

[0191] Further, the mass ratio of the alkaline solution for front surface etching treatment is 5%-10%; for example, it can be 5%, 7%, 10%, etc.

[0192] Further, the time of the front etching treatment is 40-60 minutes. For example, it can be 40 minutes, 50 minutes, 60 minutes, etc.

[0193] The above steps are respectively carried out BOE and positive etching treatment, which aims to remove the BSG layer left in the non-laser SE area of the front of the battery after boron diffusion, and form a polished surface structure of the battery.

[0194] Firstly, the battery can be pickled with a high concentration of acid solution based on a chain cleaning device, and the acid solution includes HF and HNO3. The mass ratio of the solution is 5-15%.

[0195] Then, the battery is subjected to front etching treatment by using a tank cleaning device, and the solution used is an alkaline solution of 5-10% mass ratio of NAOH or KOH, and the time is 40-60 min.

[0196] Further, the step S5 of preparing a magnesium fluoride film in the passivated battery includes:

[0197] Step S51, depositing an aluminum oxide layer on the passivated battery by using atomic layer deposition (ALD) technology;

[0198] Step S52, depositing the back SiN x passivation layer and the front SiN x passivation layer by using PECVD technology respectively; x The front SiN x passivation layer includes three layers of silicon nitride, two layers of silicon oxynitride, and one layer of silicon oxide; and the back SiN

[0199] Step S53, depositing the magnesium fluoride film on the basis of the front SiN x passivation layer;

[0200] The above steps are used for preparing an anti-reflection film, which aims to suspend the key and enhance the reflection of incident light in the passivated battery.

[0201] Firstly, an aluminum oxide layer is deposited by using atomic layer deposition (ALD) technology, with a thickness of 3-5 nm, a process temperature of 200-300°C, and a deposition time of 20-30 min.

[0202] Then, the front film is deposited by using PECVD technology, including three layers of silicon nitride, two layers of silicon oxynitride, and one layer of silicon oxide, and the back film is three layers of silicon nitride, with a thickness of 60-80 nm, a process temperature of 400-550°C, and a deposition time of 15-25 min. And a magnesium fluoride film is deposited on the basis of the above, with a thickness of 5-15 nm and a process temperature of 350-500°C.

[0203] Further, the thickness of the aluminum oxide layer is 3-5nm; for example, it can be 3nm, 4nm, 5nm, etc.

[0204] Further, the process temperature of the atomic layer deposition ALD technology is 200-300℃; for example, it can be 200℃, 250℃, 300℃, etc.

[0205] Further, the deposition time of the atomic layer deposition ALD technology is 20-30 minutes; for example, it can be 20 minutes, 25 minutes, 30 minutes, etc.

[0206] Further, the thickness of the back SiN x The thickness of the passivation layer and the positive SiN x The thickness of the passivation layer and the positive SiN

[0207] Further, the process temperature of the gas phase deposition PECVD technology is 400-550℃; for example, it can be 400℃, 450℃, 500℃, 550℃, etc.

[0208] Further, the deposition time of the gas phase deposition PECVD technology is 15-25 minutes; for example, it can be 15 minutes, 20 minutes, 25 minutes, etc.

[0209] Further, the thickness of the magnesium fluoride film is 5-15nm; for example, it can be 5nm, 10nm, 15nm, etc.

[0210] Further, the process temperature of the magnesium fluoride film is 350-500℃. For example, it can be 350℃, 400℃, 450℃, 500℃, etc.

[0211] In addition, the application also provides a power-related device comprising the magnesium fluoride film crystalline silicon photovoltaic cell as described above.

[0212] The application will be further described in the following specific examples, but it should be understood that these examples are only used for more detailed description, and should not be understood as limiting the application in any form.

[0213] Example 1:

[0214] In this embodiment, a magnesium fluoride film crystalline silicon photovoltaic cell is prepared by the following method, and the parameters of each component in the preparation are shown in Table 1.

[0215] Experimental method:

[0216] (1) Screening criteria: resistivity 0.8-1.5 Ω·cm, minority carrier lifetime greater than 1000 μs, and cell thickness 130 μm. The pre-cleaning tank contained a mixed solution of HCl and H₂O₂ at a mass ratio of 0.3%. The alkaline texturing tank contained NaOH at a mass ratio of 0.4%. The post-cleaning tank contained HF solution at a mass ratio of 0.2%. The texturing time was 60 min.

[0217] (2) Boron diffusion: N(P) type impurities are diffused onto a P(N) type substrate to form a PN junction, achieving a suitable doping concentration ρ / sheet resistance R. This yields the junction depth, doping concentration ρ, and sheet resistance R required for a solar cell PN junction.

[0218] Boron source: boron trichloride (BCl3), forming a poly / boron-doped amorphous silicon passivation structure at a temperature of 1200℃ and a boron deposition time of 7 min.

[0219] (3) Backside alkaline polishing: The pre-cleaning tank is a mixed solution of NaOH and H2O2 with a mass ratio of 0.3%. The alkaline solution texturing tank is NaOH with a mass ratio of 8%. The acid solution tank is HF solution with a mass ratio of 8%, and the backside alkaline polishing time is 45 min.

[0220] (4) Tunneling phosphorus poly: The deposition technology is LPCVD, the thickness of the tunneling oxide layer is 2nm, the thickness of the amorphous silicon layer is 120nm, and the reactant is silane (SiH4). The high-temperature tubular thermal decomposition of POCL3 phosphorus diffusion temperature is 600℃ and the phosphorus deposition time is 7min.

[0221] (5) BOE and positive engraving: The acidic solution for chain cleaning is HF, with a mass ratio of 12%. The tank cleaning solution is 8% NaOH by mass, and the time is 50 min.

[0222] (6) Preparation of antireflection film: A layer of aluminum oxide was deposited using atomic layer deposition (ALD) technology with a thickness of 4 nm, a process temperature of 300 °C, and a deposition time of 30 min.

[0223] Then, a positive film (positive SiN) was deposited using PECVD (phase vapor deposition) technology. x Passivation layer: three layers of silicon nitride + two layers of silicon oxynitride and one layer of silicon oxide; back film: back SiN x The passivation layer consists of three layers of silicon nitride, 70 nm thick, processed at 500 °C for 20 min. A magnesium fluoride film, 5 nm thick, is then deposited on top of this layer at 450 °C.

[0224] (7) Metallization and sintering: The metal slurry is silver and aluminum. The high-temperature sintering annealing temperature is 860℃.

[0225] (8) LECO laser sintering: By precisely controlling the energy of the laser and the irradiation time, the laser is irradiated on the silver paste to locally heat the silver paste for sintering. The thermal effect of the laser induces the melting and connection of silver particles in the silver paste.

[0226] Example 2:

[0227] In this example, a magnesium fluoride thin film crystalline silicon photovoltaic cell was prepared by the method of Example 1, and the preparation method was basically the same as that of Example 1, except that:

[0228] The thickness of the magnesium fluoride thin film deposited in step (6) was 10 nm.

[0229] Example 3:

[0230] In this example, a magnesium fluoride thin film crystalline silicon photovoltaic cell was prepared by the method of Example 1, and the preparation method was basically the same as that of Example 1, except that:

[0231] The thickness of the magnesium fluoride thin film deposited in step (6) was 15 nm.

[0232] Comparative Example 1: (Conventional Cell)

[0233] In this example, a magnesium fluoride thin film crystalline silicon photovoltaic cell was prepared by the method of Example 1, and the preparation method was basically the same as that of Example 1, except that:

[0234] In step (6), no magnesium fluoride thin film was deposited.

[0235] Lateral comparison test:

[0236] Experimental method:

[0237] In the above Examples 1-3 and Comparative Example 1, the same batch of materials was controlled, and different thicknesses of magnesium fluoride thin films were deposited after the deposition of silicon nitride. In Example 1, after the deposition of silicon nitride, the required 5 nm magnesium fluoride thin film was deposited; in Example 2, after the deposition of silicon nitride, the required 10 nm magnesium fluoride thin film was deposited; in Example 3, after the deposition of silicon nitride, the required 15 nm magnesium fluoride thin film was deposited; and in Comparative Example 1, no magnesium fluoride thin film was deposited.

[0238] The magnesium fluoride thin film crystalline silicon photovoltaic cells prepared in the above Examples 1-3 and Comparative Example 1 were subjected to the following experiments:

[0239] Different groups measured the thickness and refractive index of the prepared magnesium fluoride, and the blue film sheet passivation difference and the electrical performance parameters after printing were tested by sinton.

[0240] The electrical performance parameters of the finished battery sheet are obtained by IV test: the principle of photovoltaic cell IV test mainly involves measuring the current and voltage characteristics of solar cells to evaluate their performance. This process is based on the principle of photovoltaic effect, by simulating the current and voltage output under different light conditions, to draw the current-voltage (IV) curve. These curves reflect the performance of photovoltaic devices under different light and load conditions, and are an important basis for evaluating the performance of photovoltaic devices.

[0241] Basic principle: photovoltaic IV tester evaluates the performance of solar cells by measuring their current and voltage under specific conditions. This includes measuring the current and voltage output of solar cells when exposed to sunlight, as well as calculating parameters such as power, efficiency, etc. based on these data. The tester measures the current by connecting the battery circuit, usually using a current amplifier and a measurement resistor, while measuring the voltage by connecting the positive and negative terminals of the battery, using a high-impedance amplifier and an analog-to-digital converter to ensure measurement accuracy.

[0242] Isc measurement: by connecting the battery circuit, using a current amplifier and a measurement resistor to measure the current. The current amplifier amplifies the current signal and sends it to the measurement resistor, and the current value is calculated by measuring the voltage on the measurement resistor.

[0243] Uoc measurement: by connecting the positive and negative terminals of the battery, directly measuring the voltage, using a weak current through a voltage amplifier to amplify the voltage signal for measurement.

[0244] FF, Rs, Rsh, IRev1, Jo1_(A / cm 2 ), Jo2_(A / cm 2 ) data analysis: by analyzing the shape and characteristics of the IV curve, the working state and potential problems of the photovoltaic module can be determined, such as panel aging, thermal effects or connection problems.

[0245] Experimental results and analysis:

[0246] Table 2, performance test results of the batteries prepared in examples and comparative examples

[0247]

[0248] In the above table, "average" is the average of the test results of each index of Examples 1-3; "difference" is the difference between the average and the test results of Comparative Example 1; "comp1" represents "Comparative Example 1"; "real" represents examples, such as "real1" represents Example 1.

[0249] From the above table, it can be seen that the superimposed magnesium fluoride film battery has no difference in Uoc compared with the conventional battery (comparative example 1), the main difference is that the Isc is 152 mA higher and the FF is 0.45% lower. The reason is that the magnesium fluoride material has a certain influence on the contact of the metal electrode, and the contact resistance is relatively large.

[0250] The magnesium fluoride battery provided by the application has obvious advantages in Isc, increases the photoelectric conversion efficiency of the photovoltaic cell, and obviously improves the benefit.

[0251] The above is the preferred embodiment and the corresponding example of the application. It should be pointed out that for ordinary skilled persons in the art, without departing from the inventive concept, a number of modifications and improvements can be made, including but not limited to the adjustment of the ratio, the process, the amount and the reaction container, which are all within the protection scope of the application.

Claims

1. A magnesium fluoride thin-film crystalline silicon photovoltaic cell, characterized in that, The structure of the magnesium fluoride thin-film crystalline silicon photovoltaic cell, from bottom to top, includes: Back metal electrode layer, back SiN x Passivation layer, tunneling polyphosphorus-doped amorphous silicon layer, N-Si silicon substrate, P + Emitter layer, positive SiN x Passivation layer, magnesium fluoride thin film and front metal electrode layer; Preferably, the N-Si silicon substrate is an N-type primary silicon wafer; Preferably, the P + The emitter layer is obtained by external doping with trivalent boron; Preferably, the tunneling polyphosphorus-doped amorphous silicon layer is obtained by depositing an amorphous silicon layer on the surface of silicon dioxide using a deposition technique, followed by high-temperature phosphorus diffusion. Preferably, the SiN x The passivation layer was obtained by sequentially depositing aluminum oxide and silicon oxynitride; Preferably, the front metal electrode layer and the back metal electrode layer are obtained by screen printing metal paste.

2. A method for preparing a magnesium fluoride thin-film crystalline silicon photovoltaic cell as described in claim 1, characterized in that, include: The N-type silicon wafer is texturized and cleaned to obtain an N-si silicon substrate with a metal gate area on the front side. Boron diffusion is performed on the metal gate region on the front side of the N-Si silicon substrate to form P on the front side of the N-Si silicon substrate. + Emitter layer; The back side of the N-si silicon substrate is subjected to alkaline polishing, and the surface of the polished N-si silicon substrate is subjected to tunneling phosphorus poly treatment to obtain a tunneling poly phosphorus-doped amorphous silicon layer of the N-si silicon substrate, which constitutes a passivated cell. The front side of the N-si silicon substrate is etched to form a polished surface structure on the front side of the N-si silicon substrate of the passivated cell; Backside SiN was prepared for the passivated cells respectively. x Passivation layer and positive SiN x Passivation layer, and in the positive SiN x Magnesium fluoride thin films were prepared on the basis of the passivation layer; The magnesium fluoride thin-film crystalline silicon photovoltaic cell is obtained by metallizing with silver paste and laser sintering to form a back metal electrode layer and a front metal electrode layer.

3. The method for preparing magnesium fluoride thin-film crystalline silicon photovoltaic cells as described in claim 2, characterized in that, The texturing and cleaning process of the N-type silicon wafer to obtain an N-Si silicon substrate with a metal gate line region on the front side includes: The N-type silicon wafer is subjected to pre-cleaning, alkaline solution texturing, and post-cleaning processes in the texturing and cleaning process to obtain an N-Si silicon substrate with the metal gate line region on the front side. Preferably, the cleaning solution for the pre-cleaning treatment is a mixed solution of HCl and H2O2; Preferably, the mass ratio of the HCl and H2O2 mixed solution is 0.2%-0.5%; Preferably, the cleaning solution for the alkaline texturing treatment is NaOH or KOH; Preferably, the mass ratio of the cleaning solution in the alkaline solution texturing treatment is 0.4%-1.3%; Preferably, the cleaning solution for the post-cleaning treatment is an HF solution; Preferably, the HF solution contains 0.1%-0.3% by mass; Preferably, the texturing time for the texturing and washing process is 40-60 minutes.

4. The method for preparing magnesium fluoride thin-film crystalline silicon photovoltaic cells as described in claim 3, characterized in that, The screening criteria for the N-type primary silicon wafers include: The resistivity ranges from 0.8 Ω·cm to 1.5 Ω·cm; Minority carrier lifetime greater than 1000 μs; The battery thickness is between 100μm and 180μm.

5. The method for preparing magnesium fluoride thin-film crystalline silicon photovoltaic cells as described in claim 2, characterized in that, The boron source for the boron diffusion treatment includes at least one of boron tribromide and boron trichloride; The process conditions for the boron diffusion treatment include: The temperature is 900℃-1000℃; The sheet resistance is 350 ohms-500 ohms; Doping concentration of 1×10 18 -1×10 19 ; The PN junction depth is 0.7μm-0.8μm.

6. The method for preparing magnesium fluoride thin-film crystalline silicon photovoltaic cells as described in claim 2, characterized in that, The alkaline polishing treatment of the back side of the N-Si silicon substrate includes: The back side of the N-Si silicon substrate is subjected to pre-cleaning, alkaline solution treatment, and acid solution treatment in sequence as described in the alkaline polishing process; Preferably, the cleaning solution used for pre-cleaning in the alkaline polishing treatment is a mixed solution of NaOH and H2O2, or a mixed solution of KOH and H2O2; Preferably, the mass ratio of the cleaning solution used in the pre-cleaning process during alkaline polishing is 0.3%-0.5%; Preferably, the cleaning solution used in the alkaline polishing process is a NaOH solution or a KOH solution; Preferably, the mass ratio of the cleaning solution treated with alkali in the alkaline polishing process is 4%-12%; Preferably, the cleaning solution used in the alkaline polishing process is an HF solution or an HCl solution; Preferably, the mass ratio of the cleaning solution treated with acid in the alkaline polishing process is 3%-10%; Preferably, the alkaline polishing treatment takes 30-60 minutes.

7. The method for preparing magnesium fluoride thin-film crystalline silicon photovoltaic cells as described in claim 2, characterized in that, The process of tunneling phosphorus poly treatment on the polished N-si silicon substrate surface includes: The polished N-Si silicon substrate surface is subjected to deposition treatment; Then, phosphorus doping is performed using high-temperature tubular thermal decomposition POCl3 technology to obtain a tunneling polyphosphorus-doped amorphous silicon layer on the surface of the N-si silicon substrate. Preferably, in the deposition process, the thickness of the tunneling oxide layer is 1 nm-3 nm; the thickness of the amorphous silicon layer is 100 nm-200 nm; and the reactant in the deposition process is silane. Preferably, the temperature for the phosphorus doping treatment is 600℃-800℃; Preferably, the phosphorus deposition time for the phosphorus doping treatment is 5-7 minutes; Preferably, the phosphorus doping treatment has a sheet resistance of 40 ohms-60 ohms and a concentration of 3 × 10⁻⁶ ohms. 19 -4×10 20 .

8. The method for preparing magnesium fluoride thin-film crystalline silicon photovoltaic cells as described in claim 2, characterized in that, The etching process on the front side of the N-si silicon substrate to form the polished surface structure of the front side of the N-si silicon substrate for the passivated cell includes: The front side of the N-Si silicon substrate is acid-washed with an acidic solution; The passivated cell is subjected to front-side etching to form a polished surface structure on the front side of the N-si silicon substrate of the passivated cell; Preferably, in the pickling process, the acidic solution is HF or HNO3; Preferably, the mass ratio of the acidic solution is 5%-15%; Preferably, the alkaline solution for the front etching treatment is NaOH or KOH; Preferably, the mass ratio of the alkaline solution for the front etching treatment is 5%-10%; Preferably, the etching process on the front side takes 40-60 minutes.

9. The method for preparing a magnesium fluoride thin-film crystalline silicon photovoltaic cell as described in claim 2, characterized in that, The preparation of a magnesium fluoride thin film inside the passivated battery includes: An aluminum oxide layer was deposited on the passivated battery using atomic layer deposition (ALD) technology; The back SiN was deposited using PECVD (Prepared Chemical Vapor Deposition) technology. x passivation layer and the positive SiN x Passivation layer; wherein the positive SiN x The passivation layer comprises three layers of silicon nitride, two layers of silicon oxynitride, and one layer of silicon oxide; the back SiN x The passivation layer is a three-layer silicon nitride layer; In the positive SiN x The magnesium fluoride film is deposited on top of the passivation layer; Preferably, the thickness of the alumina layer is 3nm-5nm; Preferably, the process temperature of the atomic layer deposition (ALD) technology is 200℃-300℃; Preferably, the deposition time of the atomic layer deposition (ALD) technique is 20-30 minutes; Preferably, the back SiN x passivation layer and the positive SiN x The thickness of the passivation layer is 5-15 nm; Preferably, the process temperature of the PECVD vapor deposition technology is 400℃-550℃; Preferably, the deposition time of the PECVD (phase vapor deposition) technology is 15-25 minutes; Preferably, the thickness of the magnesium fluoride film is 5nm-15nm; Preferably, the process temperature of the magnesium fluoride film is 350℃-500℃.

10. An electrical-related device, characterized in that, Including the magnesium fluoride thin-film crystalline silicon photovoltaic cell as described in claim 1.

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