Passivation method of silicon battery piece, preparation method of silicon-calcium laminated battery and device

Abstract

The invention relates to a passivation method of a silicon battery piece, which comprises the following steps of: placing the silicon battery piece in a reaction cavity, and exposing a to-be-passivated region on the silicon battery piece in the reaction cavity; a gaseous passivation material is conveyed into the reaction cavity, the passivation material is tris (2, 2-dimethyl propyl) aluminum, and the passivation material is input into the reaction cavity through carrier gas; an oxygen source is conveyed into the reaction cavity in a pulse mode, and the oxygen source and the passivation material interact to passivate the to-be-passivated area; after an oxygen source, tri (2, 2-dimethyl propyl) aluminum and a silicon dangling bond interact, passivating the dangling bond and generating aluminum oxide in a passivation region; and circularly passivating, taking out the silicon battery piece, and annealing to obtain the passivated silicon battery piece. According to the method, the defect state density of the silicon battery piece is effectively reduced, and the battery efficiency is further improved. The passivation method provided by the invention not only can be used for passivating a silicon battery piece in a silicon-calcium laminated battery, but also can be used for a crystalline silicon battery or other silicon battery piece products needing passivation of dangling bonds.

Description

Technical Field

[0001] The present invention relates to a passivation method for a silicon solar cell, a preparation method for a silicon-calcium stacked battery and a device, and belongs to the field of new energy. Background Art

[0002] As global energy demand continues to grow, the development and utilization of solar energy as a clean, renewable energy source has garnered widespread attention. Currently, crystalline silicon solar cells (including monocrystalline and polycrystalline silicon) are the dominant technology in the market, with their photoelectric conversion efficiency approaching its theoretical limit. The highest laboratory efficiency for monocrystalline silicon cells is 26%-27%, while the efficiency of polycrystalline silicon cells generally ranges from 20%-22%. However, in practice, these efficiencies are often lower due to manufacturing processes, material defects, and environmental factors. Furthermore, crystalline silicon cells experience photodegradation (PID) under prolonged sunlight, leading to a gradual decline in performance and limiting their long-term stability and power generation capacity.

[0003] In recent years, perovskite solar cells have become a research hotspot due to their excellent photovoltaic properties. The theoretical efficiency of a single-junction perovskite cell can reach 31%, and by combining it with a crystalline silicon cell to form a stacked structure, the theoretical efficiency is expected to exceed 45%. Perovskite materials have the advantages of abundant raw materials and low cost. The preparation cost of their core components (such as metal halides) is far lower than that of high-purity silicon materials. Furthermore, perovskite cells can be prepared using solution methods (such as spin coating, inkjet printing, and slit coating), which are simple and energy-efficient, making them suitable for large-scale industrial production and significantly reducing manufacturing costs.

[0004] However, practical applications of perovskite / crystalline silicon tandem cells still face challenges. On silicon substrates, dangling bonds and defect states generated during the slicing process can trigger non-radiative recombination of charge carriers, reducing the open-circuit voltage (Voc) and fill factor (FF), thereby impacting the overall performance of the cell. Therefore, effectively suppressing interfacial recombination and improving carrier collection efficiency have become key technical challenges in improving the efficiency of perovskite / crystalline silicon tandem cells. Summary of the Invention

[0005] To passivate dangling bonds or defects at the edges of silicon cells, this paper proposes a passivation method for silicon cells. This passivation effectively reduces the defect state density, thereby improving cell efficiency. The passivation method can be used not only to passivate silicon cells in silicon-calcium tandem cells, but also in crystalline silicon cells or other silicon cell products requiring dangling bond passivation.

[0006] One solution adopted by the present invention is: a passivation method for silicon solar cells, comprising the following steps: S01 placing the silicon cell in the reaction chamber, with the area to be passivated of the silicon cell exposed in the reaction chamber; S02 delivers a passivation material into the reaction chamber. The passivation material is tris(2,2-dimethylpropyl)aluminum. The passivation material is delivered into the reaction chamber via a carrier gas. SO3 is delivered into the reaction chamber in a pulsed form. The oxygen source and tris(2,2-dimethylpropyl)aluminum react in the passivation zone to generate aluminum oxide. S04 cyclically operates S02 and S03 to a set number of times or a set time; S05: Take out the silicon cell, anneal it, and obtain the passivated silicon cell.

[0007] As a preferred method, the passivation material is delivered into the reaction chamber via a carrier gas in pulses of 0.05-0.2 seconds, followed by a purge with an inert gas or carrier gas. During the pulses, the concentration of the aluminum source in the reaction chamber is 0.1-0.5 mg / cycle·cm², and the aluminum source is introduced at a rate of 10-50 sccm.

[0008] As a preferred embodiment, the oxygen source is O3 or H2O, which is input into the reaction chamber in the form of pulses with a pulse time of 0.02-0.1s. After the pulse ends, an inert gas or carrier gas is used for purging.

[0009] As a preferred embodiment, step S02 is specifically to heat tri(2,2-dimethylpropyl)aluminum to 80° C.-100° C. and then introduce it into the reaction chamber, so that tri(2,2-dimethylpropyl)aluminum is adsorbed on the surface of the passivation area.

[0010] As a preferred embodiment, the number of cycles of step S02 and step S03 is 50-200, and the thickness of the aluminum oxide film formed in the passivation area is 5-20 nm.

[0011] As a preferred embodiment, the annealing temperature in step S05 is 0-150°C.

[0012] The second solution is: a device comprising a silicon cell obtained by the passivation method of the first solution.

[0013] The third solution is: a method for preparing a silicon-calcium stack battery, comprising the following steps: S01 Obtaining silicon solar cells: The silicon solar cells are processed by a passivation method in one of the schemes; S02 Preparation of hole transport layer: depositing a hole transport layer on the silicon cell, wherein the hole transport layer contains at least one hole transport material, and the hole transport layer is deposited by a combination of one or more of spin coating, doctor blade coating, printing, magnetron sputtering, evaporation, and atomic deposition; S03 preparing a perovskite layer: depositing a perovskite layer on the hole transport layer, wherein the hole transport layer is in direct or indirect contact with the perovskite layer, wherein the indirect contact is through an intermediate layer, and the perovskite layer contains at least one perovskite light absorbing material; S04 preparing an electron transport layer: depositing an electron transport layer on the perovskite layer, wherein the electron transport layer is in direct or indirect contact with the perovskite layer, wherein the indirect contact is through an intermediate layer, and the electron transport layer contains at least one electron transport material; S05 prepares the electrode layer.

[0014] As a preferred embodiment, the hole transport material is MeO-2PACz, and the perovskite light absorbing material of the perovskite layer is Cs x1 FA x2 MA （1-x1-x2） Pb(I y1 Br （1-y1） )3, 0<x1<1, 0<x2<1, 0<x1+x2<1, 0<y1<1.

[0015] As a preferred embodiment, the area of the silicon solar cell to be passivated is a cutting surface generated when the silicon solar cell is cut, and the dangling bonds are dangling bonds on the cutting surface.

[0016] As a preferred method, the hole transport layer is prepared by: a. Mixing MeO-2PACz with ethanol solution to obtain MeO-2PACz solution; b Spin-coat the MeO-2PACz solution on the silicon cell to obtain the MeO-2PACz hole transport layer.

[0017] The preparation method of the perovskite layer is: a. Dissolve FAI, FABr, MAI, MABr, PbI2, PbBr2, and CsI in N-dimethylformamide and dimethyl sulfoxide to obtain a precursor solution. b. Heat the precursor solution to completely dissolve and obtain Cs x1 FA x2 MA （1-x1-x2） Pb(I y1 Br （1-y1） ) 3 solution; c will Cs x1 FA x2 MA （1-x1-x2） Pb(I y1 Br （1-y1） ) 3. Spin-coat the solution onto the hole transport layer and add toluene dropwise when the spin-coating time is set; d Annealing in a nitrogen atmosphere to obtain a perovskite layer.

[0018] The beneficial effects of the present invention are as follows: the present invention uses TDMAP-Al as a passivation material precursor. The aluminum atoms in this material are surrounded by three tert-butyl groups, which has low steric hindrance, thereby reducing the reaction rate of each ALD cycle, allowing O3 to fully oxidize the aluminum atomic center. In addition, the low-temperature reactivity of this material is controllable, and it can generate a dense and low-interface aluminum oxide layer under low temperature conditions, which is suitable for uniform coverage of steep-edge structures. DETAILED DESCRIPTION

[0019] The present invention will be described in more detail below, but it should not be construed that protection scope of the present invention is subject to the following description. Unless otherwise specified, any scope described in the present invention includes any sub-range consisting of any numerical value between the end value and the end value and any numerical value between the end value or the end value. All raw materials of the present invention are not particularly limited in purity, and the present invention preferably adopts analytical pure. All raw materials of the present invention, their source and abbreviation all belong to conventional sources and abbreviations in this area, are all clear and definite in the field of their related uses, and those skilled in the art can purchase or prepare by conventional methods from commercially available sources according to abbreviations and corresponding uses.

[0020] "At least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b, c can be single or plural.

[0021] Those skilled in the art will appreciate that perovskite materials can be represented by the general formula [A][B][X]3, where [A] is at least one monovalent cation, [B] is at least one divalent cation, and [X] is at least one anion. When the perovskite includes more than one A cation, the different A cations can be distributed on the A sites in an ordered or disordered manner. When the perovskite includes more than one B cation, the different B cations can be distributed on the B sites in an ordered or disordered manner. When the perovskite includes more than one X anion, the different X anions can be distributed on the X sites in an ordered or disordered manner.

[0022] The present invention proposes a passivation method for dangling bonds in silicon solar cells, with the aim of reducing the defect state density of silicon solar cells, increasing carrier transfer efficiency, and improving cell efficiency. The proposed silicon cell passivation method is preferably processed in an atomic deposition device, comprising the following steps: S01 placing the silicon cell in a reaction chamber of the atomic deposition device and exposing the area to be passivated. If the silicon cell generates dangling bonds during the cutting process, the area to be passivated is the cut surface; S02 starting the device, delivering a passivation material tri(2,2-dimethylpropyl)aluminum into the reaction chamber, preferably the passivation material is a powder, mixed with a carrier gas, heated and vaporized, and then delivered to the reaction chamber. The carrier gas is a protective gas, preferably nitrogen, and the passivation material is adsorbed on the surface to be passivated to form a single layer coverage; S03 stopping the delivery of tri(2,2-dimethylpropyl)aluminum and delivering an oxygen source into the reaction chamber. The oxygen source reacts with the passivation material on the passivation surface to form aluminum oxide and passivates the dangling bonds; S04 repeating steps S02 and S03 for a certain number of times or until passivation is completed; S05 taking out the passivated silicon cell and annealing it in a nitrogen atmosphere to obtain the desired silicon cell. The annealing temperature is preferably 100-150° C., more preferably 140-150° C. At this temperature, the perovskite structure will not be destroyed, and the incompletely decomposed TDMAP-Al will be secondary decomposed to avoid defects.

[0023] In one embodiment, the passivation material is heated to 70-90°C, preferably 80°C, before being introduced into the reaction chamber for reaction. At this temperature, the vapor pressure of TDMAP-Al in the carrier gas N2 forms a stable flow, allowing the passivation material and carrier gas mixture to be delivered into the reaction chamber in pulses. The pulse duration is 0.05-0.2 seconds. In specific implementations, the pulse duration can be set to 0.05 seconds, 0.07 seconds, 0.09 seconds, 0.1 seconds, 0.12 seconds, 0.18 seconds, and 0.2 seconds. After the pulse, an inert gas or carrier gas is introduced to purge and remove unreacted passivation material. After the purge is completed, an oxygen source is introduced in pulses. The oxygen source in the present invention can be O3 or H2O. O3 or H2O is introduced in gaseous form. If it is O3, 200g / Nm³ of O3 is introduced during the reaction. The pulse time is 0.02-0.1s. In specific implementation, the pulse time can be 0.02s, 0.06s, 0.09s or 0.1s. After the end, an inert gas or carrier gas is introduced to purge and remove by-products. The purge time is 5-10s, which can be 5s, 6s, 7s, 9s, or 10s. The passivation material and oxygen source are circulated to fully passivate the silicon solar cell. The reaction process involved in this process is: (1) Main reaction: Al(CH2C(CH3)3)3(g)+O3(g)→Al-O*+(CH2C(CH3)3)2O(g)+by-product (2) Subsequent O3 pulses further oxidize Al-O* to Al2O3: 2Al-O*+O3→Al2O3+O2(g) The overall reaction equation is: 2Al(CH2C(CH3)3)3+3O3→Al2O3+6(CH3)2C=CH2↑+3H2↑+O2↑. After multiple cycles, a 5-20nm thick layer of Al2O3 is finally formed. After the reaction is complete, the silicon cell is removed and annealed at 100-150°C to obtain the finished silicon cell.

[0024] The silicon cell of the present invention can be used to prepare silicon cells and silicon-calcium tandem solar cells. When used as the silicon substrate in silicon-calcium tandem solar cells, it is beneficial to reduce the non-radiative recombination of carriers and improve cell efficiency. The silicon-calcium tandem solar cell can be a two-terminal cell or a four-terminal cell, with the silicon cell arranged on the light-facing side and the perovskite cell arranged on the backlight side, or the silicon cell arranged on the backlight side and the perovskite cell arranged on the light-facing side. The silicon cell can be an HJT cell, a PERC cell or a TOPCON cell, and the perovskite cell can be a positive perovskite cell or an inverted perovskite cell. The preparation method is specifically described below using a two-terminal tandem cell as an example. The two-terminal tandem cell uses a silicon cell as the bottom cell and an inverted perovskite cell as the top cell.

[0025] The preparation method of the two-terminal stacked battery is as follows: S01 Obtaining silicon solar cells: Cutting silicon solar cells into required sizes as needed, and passivating them using the passivation method for silicon solar cells of the present invention; S02 Preparation of hole transport layer: Prepare a hole transport layer on a silicon cell, or prepare a hole transport layer after preparing a first intermediate layer. The first intermediate layer can be one or more layers, such as a tunneling layer, a conductive layer, a modification layer, a passivation layer, etc. The hole transport layer contains one or more hole transport materials, and the hole transport material may or may not contain additives. The hole transport material can be nickel oxide, copper oxide, SAM-type materials, carbazole-type materials, thiophene-type materials, etc. The deposition method can be a combination of one or more of spin coating, doctor blade coating, printing, magnetron sputtering, evaporation, and atomic deposition. The preferred preparation method is: a. Mix MeO-2PACz with an ethanol solution to obtain a MeO-2PACz solution; b. Spin-coat the MeO-2PACz solution on a silicon cell to obtain a MeO-2PACz hole transport layer; S03 Preparation of perovskite layer: preparing a perovskite layer on the hole transport layer, or preparing a perovskite layer after preparing a second intermediate layer, the second intermediate layer can be one or more layers, such as one or more layers of an energy level transition layer, a modification layer, a passivation layer, and a light adjustment layer, the perovskite layer contains at least one perovskite material, the perovskite material generates electrons and holes under light excitation, the electrons are extracted and exported by the electron transport layer, and the holes are extracted and exported by the hole transport layer, the perovskite layer may contain additives in addition to the perovskite material, the perovskite layer may be one or more layers, and when there are multiple perovskite layers, perovskite layers with different band gaps may be included to improve the light absorption rate, the preparation method of the perovskite layer may be a combination of one or more of spin coating, doctor blading, printing, magnetron sputtering, evaporation, and atomic deposition, such as preparing an inorganic layer by evaporation and preparing an organic layer by spin coating, thereby obtaining a high-quality perovskite layer. The preferred preparation method is as follows: a. dissolving FAI, FABr, MAI, MABr, PbI2, PbBr2, and CsI in a set ratio in N-N-dimethylformamide and dimethyl sulfoxide to obtain a precursor solution; b. heating the precursor solution until it is completely dissolved to obtain Cs x1 FA x2 MA （1-x1-x2） Pb(I y1 Br （1-y1） ) 3 solution; c. Spin-coat the solution on the hole transport layer and add toluene dropwise when the spin-coating time is set; d. Anneal under a nitrogen atmosphere to obtain a perovskite layer. Cs x1 FA x2 MA （1-x1-x2） Pb(I y1 Br （1-y1） )3 is preferably Cs 0.1 FA 0.2 MA 0.7 Pb(I 0.76 Br 0.24 )3; S04 Preparation of an electron transport layer: An electron transport layer is prepared on the perovskite layer, or after preparing a third intermediate layer on the perovskite layer. The third intermediate layer can be one or more types, such as an energy level transition layer, a modification layer, a passivation layer, and a light modulation layer. The electron transport layer can contain only one electron extraction material or multiple different types of electron extraction materials, such as fullerene, PCBM, TiO2, SnO2, etc. In addition to the electron extraction material, the electron transport layer may also contain additives. The electron transport layer can be prepared by a combination of one or more of spin coating, doctor blade coating, printing, magnetron sputtering, evaporation, and atomic deposition. S05 Preparation of the Electrode Layer: The electrode layer is formed directly on the electron transport layer or after the fourth intermediate layer. The fourth intermediate layer can be a single layer or multiple layers, such as a hole blocking layer, a light regulating layer, a modification layer, a passivation layer, etc. The electrode layer is a transparent conductive layer and a metal grid line layer, which collects electrons introduced by the electron transport layer. Example 1

[0026] The passivation method of the silicon solar cell in this embodiment is: 1. Obtain silicon cells Cutting the silicon solar cell into required sizes and ultrasonically cleaning the cut silicon solar cell; 2. Load the silicon cell into the passivation device The passivation equipment is an ALD equipment (atomic deposition equipment). The silicon cell is fixed in the reaction chamber of the ALD equipment so that the passivation area of the silicon cell is exposed. The passivation area is the cutting surface by default. 3. TDMAP-Al pulse stage Tris(2,2-dimethylpropyl)aluminum (TDMAP-Al, Al(CH2CH2C(CH3)2)3) was used as the passivation material. After the passivation material was heated to 80°C and vaporized, the carrier gas N2 was started to be supplied with a pulse time of 0.1 s. 4. First purge After the TDMAP-Al pulse, N2 was purged for 5s to remove the unreacted passivation material; 5. Oxygen source (O3) pulse stage O3 (concentration of 200g / Nm³, temperature of 120°C) was introduced into the reaction chamber through an ozone generator. The pulse time of this stage was 0.05s. 6. Second purge After the oxygen source pulse stage, N2 was purged for 5s to remove unreacted passivation materials and reaction byproducts; 7. Repeat steps 3 to 6 for 100 cycles. 8. Post-processing: Take out the silicon cell from the reaction chamber and anneal it at 150°C for 10 minutes to obtain a stable silicon cell.

[0027] An ITO tunneling layer is prepared on the passivated silicon cell, and then a silicon-calcium two-terminal stacked cell is prepared, with the silicon cell as the bottom cell and the perovskite cell as the top cell. The preparation method is as follows: 1. Mix 1 mg of MeO-2PACz with 1 mL of ethanol solution to obtain a 1 mg / mL MeO-2PACz solution. After filtering to remove large particles, the solution was spin-coated on the side of the silicon cell with the tunneling layer at a spin coating rate of 3300 rpm for 30 seconds. Anneal at 120°C for 10 minutes to obtain a MeO-2PACz hole transport layer approximately 3 nm thick. 2. Preparation of Cs 0.1 FA 0.2 MA 0.7 Pb(I 0.76 Br 0.24 ) 3) Solution: Dissolve 27.5152 mg of FAI, 19.9949 mg of FABr, 120.8172 mg of MAI, 40.3092 mg of MABr, 691.515 mg of PbI2, 36.701 mg of PbBr2, and 41.5696 mg of CsI in 0.80 mL of DMF (NN-dimethylformamide) and 0.2 mL of DMSO (dimethyl sulfoxide). Heat to 70 °C and stir for 2 hours until completely dissolved. Filter through a 0.45 μm filter cartridge to remove larger particles in the solution to obtain 1.6 M CsI. 0.1 FA 0.2 MA 0.7 Pb(I 0.76 Br 0.24 ) 3) Solution. 0.1 FA 0.2 MA 0.7 Pb(I 0.76 Br 0.24 3) Spin-coat the solution onto the hole transport layer at a speed of 3000 rpm for 30 seconds. At the 10th second mark of spin-coating, evenly add 150 μL of the antisolvent toluene onto the film. Anneal the film at 100°C for 30 minutes under a nitrogen atmosphere, cool, and set aside to form a 450 nm thick perovskite layer. 3. Use vacuum evaporation equipment to evaporate C by thermal evaporation. 60 material, forming a 20nm electron transport layer on the perovskite layer; 4. Preparation of hole blocking layer: Using ALD atomic layer deposition equipment, a 10nm hole blocking layer is formed on the electron transport layer by atomic layer deposition of SnO2; 5. Preparation of electrodes: A layer of ITO is deposited on the surface of the hole blocking layer by thermal evaporation, and then a silver electrode is prepared. Example 2

[0028] The difference from Example 1 is that the process parameters are different. The passivation method of the silicon cell in this comparative example is: 1. Obtain silicon cells Cutting the silicon cell material into silicon cell slices of a desired size, and ultrasonically cleaning the cut silicon cell slices; 2. Load the silicon cell into the passivation device The passivation equipment is an ALD equipment (atomic deposition equipment). The silicon cell is fixed in the reaction chamber of the ALD equipment so that the passivation area of the silicon cell is exposed. The passivation area is the cutting surface by default. 3. TDMAP-Al pulse stage Tris(2,2-dimethylpropyl)aluminum (TDMAP-Al, Al(CH2CH2C(CH3)2)3) was used as the precursor passivation material. After the material was heated to 100°C and vaporized, the carrier gas N2 was started to be supplied with a pulse time of 0.15s. 4. First purge After the TDMAP-Al pulse, N2 was purged for 5s to remove the unreacted precursor; 5. Oxygen source (O3) pulse stage O3 (concentration of 200g / Nm³, temperature of 120°C) was introduced into the reaction chamber through an ozone generator. The pulse time of this stage was 0.1s. 6. Second purge After the oxygen source pulse stage, N2 was purged for 7s to remove unreacted precursors and reaction byproducts; 7. Repeat steps 3 to 6 for a total of 150 times and then end; 8. Post-processing: Take out the silicon cell from the reaction chamber and anneal it at 100°C for 10 minutes to obtain a stable silicon cell.

[0029] The silicon cell obtained by the above passivation method is used to prepare a silicon-calcium stacked battery. The preparation method of the battery is the same as that of Example 1. Example 3

[0030] The difference between Example 3 and Example 1 is that the process parameters are different. The passivation method of the silicon solar cell in this comparative example is: 1. Obtain silicon cells Cutting the silicon cell material into silicon cell slices of a desired size, and ultrasonically cleaning the cut silicon cell slices; 2. Load the silicon cell into the passivation device The passivation equipment is an ALD equipment (atomic deposition equipment). The silicon cell is fixed in the reaction chamber of the ALD equipment so that the passivation area of the silicon cell is exposed. The passivation area is the cutting surface by default. 3. TDMAP-Al pulse stage Tris(2,2-dimethylpropyl)aluminum (TDMAP-Al, Al(CH2CH2C(CH3)2)3) was used as the precursor material. After the precursor material was heated to 95°C and vaporized, the carrier gas N2 was started to be supplied with a pulse time of 0.2s. 4. First purge After the TDMAP-Al pulse, N2 was purged for 5s to remove the unreacted precursor; 5. Oxygen source (O3) pulse stage O3 (concentration of 200g / Nm³, temperature of 120°C) was introduced into the reaction chamber through an ozone generator. The pulse time of this stage was 0.1s. 6. Second purge After the oxygen source pulse stage, N2 was purged for 7s to remove unreacted precursors and reaction byproducts; 7. Repeat steps 3 to 6 for 100 cycles. 8. Post-processing: Take out the silicon cell from the reaction chamber and anneal it at 100°C for 10 minutes to obtain a stable silicon cell.

[0031] The silicon cell obtained by the above passivation method is used to prepare a silicon-calcium stacked battery. The preparation method of the battery is the same as that of Example 1.

[0032] Comparative Example The only difference from the embodiment is the passivation method of the silicon solar cell. The passivation method of the silicon solar cell in this comparative example is: 1. Obtain silicon cells Cutting the silicon cell material into silicon cell slices of a desired size, and ultrasonically cleaning the cut silicon cell slices; 2. Load the silicon cell into the passivation device The passivation equipment is an ALD equipment (atomic deposition equipment). The silicon cell is fixed in the reaction chamber of the ALD equipment so that the passivation area of the silicon cell is exposed. The passivation area is the cutting surface by default. 3. TMA pulse stage TMA was used as the precursor material. After the precursor material was vaporized at room temperature, the carrier gas N2 was supplied with a pulse time of 0.1 s. 4. First purge After the TMA pulse, N2 was purged for 5 s to remove the unreacted precursor; 5. Oxygen source (H2O) pulse stage Vaporized H2O (vaporized after passing through the heating pipe) is introduced into the reaction chamber. The pulse time of this stage is 0.05s. 6. Second purge After the oxygen source pulse stage, N2 was purged for 5s to remove unreacted precursors and reaction byproducts; 7. Repeat steps 3 to 6 for 100 cycles. 8. Post-processing: Take out the silicon cell from the reaction chamber and anneal it at 200°C for 10 minutes to obtain a stable silicon cell.

[0033] The silicon cell obtained by the above passivation method is used to prepare a silicon-calcium stacked battery. The preparation method of the battery is the same as that of Example 1.

[0034] Data testing: The performance parameters of the silicon-calcium stacked cells in Example 1 and the comparative example are tested, as shown in Table 1. It can be seen that the cells passivated by TDMAP-Al-ALD in the example show significantly excellent performance in open circuit voltage Voc (V), fill factor FF (%), short circuit current Js (mA / cm²), and cell efficiency.

[0035] Table 1 IV test data of batteries in Examples and Comparative Examples parameter TMA-ALD passivated cell (comparative example) TDMAP-Al-ALD passivation cell (Example 1) TDMAP-Al-ALD passivation cell (Example 2) TDMAP-Al-ALD passivation cell (Example 3) Voc (V) 1.820 1.838 1.825 1.827 FF (%) 81.2 83.4 83.1 82.9 Jsc (mA / cm²) 18.8 19.0 19.0 19.0 efficiency(%) 27.8 29.1 28.81 28.77 The C content and Al2O3 interface density of the silicon cell in Example 1 and the silicon cell in the comparative example after passivation treatment were tested. The results are shown in Table 2. It can be seen that the quality of the interface film layer formed after passivation is optimized, showing low defects and high density.

[0036] Table 2 XPS and CV tests (carbon residue and interface state density) index TMA process (comparative example) TDMAP-Al process (Example 1) TDMAP-Al process (Example 2) TDMAP-Al process (Example 3) C content (at%) 5.8 0.7 0.68 0.69 <![CDATA[Interface state density (eV -1 cm -2 )]]> 5.2×10¹¹ 0.8×10¹¹ 0.87×10¹¹ 0.83×10¹¹ The interface between the Al2O3 film formed in Example 1 and the Al2O3 film formed in the comparative example was observed by SEM, and the uniformity and edge coverage of the film were analyzed. The results are shown in Table 3.

[0037] Table 3 Film uniformity and edge coverage index TMA process (comparative example) TDMAP-Al process (Example 1) TDMAP-Al process (Example 2) TDMAP-Al process (Example 3) Surface film thickness (nm) 8.2±2.19 (uneven) 10.5±0.3 (even) 10.5±0.3 (even) 10.5±0.3 (even) Surface coverage ~75% >95% >95% >95% The minority carrier lifetime was tested by QSSPC, and the results are shown in Table 4.

[0038] Table 4 QSSPC test results area TMA process (comparative example) TDMAP-Al process (example) TDMAP-Al process (Example 2) TDMAP-Al process (Example 3) Silicon cell center (μs) 185 220 215 210 Silicon cell edge (μs) 48 85 82 80 Through testing, it was found that the silicon solar cells processed by the TDMAP-Al passivation process in the present invention have the following advantages: 1. Significantly Improved Edge Passivation Performance: The minority carrier lifetime at the edge of the silicon cell (the minority carrier lifetime is the average lifetime of non-equilibrium minority carriers in a semiconductor from generation to recombination) has been increased from 50μs in the TMA process to 85μs (as measured by the quasi-steady-state photoconductivity decay method), reducing the carrier surface recombination rate. Testing the open-circuit voltage of the stacked cell under AM1.5G illumination shows a 15-25mV improvement with the TDMAP-Al passivation process.

[0039] 2. Excellent low temperature annealing performance Compared to the TMA passivation process in the comparative example, which requires annealing at temperatures of 200°C or above, the TDMAP-Al in the example maintains high reaction efficiency at low temperatures (50-150°C), preventing thermal degradation of the perovskite top layer. Furthermore, the mild reaction kinetics of TDMAP-Al with O₃ are well-suited to low-temperature ALD, eliminating the need for high-temperature activation.

[0040] 3. The obtained film has low carbon residue, high coverage, low defects and high density In the examples, the tert-butyl groups of TDMAP-Al generate volatile isobutylene, leaving very little carbon residue. However, the three methyl groups (-CH3) of TMA directly bond to the aluminum (Al) center. However, the C-Al bond is weak (~70 kcal / mol) and easily breaks during the ALD reaction. However, some methyl groups cannot be completely oxidized and removed, resulting in carbon residue. SEM cross-sectional measurements revealed that the surface coverage of the silicon cell after TDMAP-Al passivation reached >95%.

[0041] 4. High process stability and repeatability At 80°C, the vapor pressure of TDMAP-Al in the example is stably maintained at 0.1 Torr (about 13.3 Pa), while the vapor pressure of TMA in the comparative example is higher than 10 Torr. This property enables controllable vapor transport during the ALD process, thereby controlling the passivation effect.

[0042] During the oxygen source supply process, the O3 pulse duration in the embodiment can be adjusted within a range of 0.02-0.1s, while the comparative example requires strict control of the oxygen source pulse duration within a range of ±0.01s. Exceeding this control range results in a sharp decline in the passivation effect. Therefore, compared with the comparative example, the passivation method in the embodiment is more stable and highly repeatable. After 30 batches of experiments, the efficiency standard deviation of the battery in the embodiment was less than 0.3%, while the efficiency standard deviation of the battery in the comparative example was as high as 0.8%.

[0043] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A passivation method for a silicon solar cell, characterized in that: The following steps are included S01 placing the silicon cell in the reaction chamber, with the area to be passivated of the silicon cell exposed in the reaction chamber; S02 delivers gaseous passivation material into the reaction chamber, the passivation material is tris(2,2-dimethylpropyl)aluminum; S03 delivers an oxygen source into the reaction chamber in a pulsed form, and the oxygen source and the passivation material interact to passivate the area to be passivated; S04 cyclically operates S02 and S03 to a set number of times or a set time; S05: Take out the silicon cell, anneal it, and obtain the passivated silicon cell.

2. The passivation method according to claim 1, characterized in that: The passivation material is transported into the reaction chamber in the form of pulses by a carrier gas, with a pulse time of 0.05-0.2s. After the pulse ends, an inert gas or a carrier gas is used for purging.

3. The passivation method according to claim 1, characterized in that: The oxygen source is O3 or H20, and the oxygen source is delivered to the reaction chamber in the form of pulses with a pulse time of 0.02-0.1s. After the pulse ends, an inert gas or carrier gas is used for purging.

4. The passivation method according to claim 1, characterized in that: Step S02 is specifically to heat tri(2,2-dimethylpropyl)aluminum to a set temperature and then introduce it into the reaction chamber, tri(2,2-dimethylpropyl)aluminum is adsorbed on the surface of the passivation area, and the set temperature is 80°C-100°C.

5. The passivation method according to claim 1, characterized in that: The number of cycles of step S02 and step S03 is 50-200. After passivation, an aluminum oxide film is formed in the area to be passivated. The thickness of the aluminum oxide film is 5-20 nm.

6. The passivation method according to claim 1, characterized in that: The annealing temperature in step S05 is 0-150°C.

7. A device, characterized in that: It comprises a silicon solar cell produced by the passivation method according to any one of claims 1 to 6.

8. A method for preparing a silicon-calcium stack battery, characterized in that: The following steps are involved: S01 Obtaining a silicon solar cell: The silicon solar cell is treated by the passivation method according to any one of claims 1 to 6; S02: preparing a hole transport layer: depositing a hole transport layer on the silicon cell, wherein the hole transport layer contains at least one hole transport material; S03 preparing a perovskite layer: depositing a perovskite layer on the hole transport layer, wherein the hole transport layer is in direct or indirect contact with the perovskite layer, and the perovskite layer contains at least one perovskite light absorbing material; S04 preparing an electron transport layer: depositing an electron transport layer on the perovskite layer, the electron transport layer being in direct or indirect contact with the perovskite layer, and the electron transport layer containing at least one electron transport material; S05 prepares the electrode layer.

9. The method for preparing a silicon-calcium stacked battery according to claim 8, characterized in that: The hole transport material is MeO-2PACz, and the perovskite light absorbing material is Cs x1 FA x2 MA （1-x1-x2） Pb(I y1 Br （1-y1） )3, 0<x1<1, 0<x2<1, 0<x1+x2<1, 0<y1<1.

10. The method for preparing a silicon-calcium stacked battery according to claim 9, characterized in that: The preparation method of the hole transport layer is as follows: a. Mixing MeO-2PACz with ethanol solution to obtain MeO-2PACz solution; b. Coating the MeO-2PACz solution on the silicon cell to obtain the MeO-2PACz hole transport layer; The preparation method of the perovskite layer is: a. Dissolve FAI, FABr, MAI, MABr, PbI2, PbBr2, and CsI in N-N-dimethylformamide and dimethyl sulfoxide in a set ratio to obtain a precursor solution; b. heating the precursor solution until it is completely dissolved; c. coating the precursor solution on the hole transport layer and adding toluene dropwise at a set time; d Annealing in a nitrogen atmosphere to obtain a perovskite layer.